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991.
For the selection of donors with valuable characteristics for breeding, 39 thyme accessions were evaluated in three years
according to a staggered schedule. The criteria investigated were: winter hardiness, beginning of flowering, growth height,
yield of the dry herb, content of essential oil, composition of the essential oil, DNA content of cell nuclei and number of
chromosomes. The most strongly varying traits between the populations were the yield of dry herb, the content of essential
oil and the content of volatile phenols with coefficients of variation (CV) between CV 40% and 50%. The largest variation
within a population was detected for the yield of dry herb (CV 25–46%) and the content of essential oil (CV 17–48%). The homogeneity
of the populations was different. The minimal average coefficient of variation of all traits (CV 19%) was determined in the
population of the cultivar ‘Varico II’ and in a population from Lithuania. The ploidy level of T. vulgaris was diploid (2n = 30). 相似文献
992.
Luigi Pane Elisabetta Giacco Christian Corrà Giuliano Greco Gian Luigi Mariottini Franco Varisco Marco Faimali 《Journal of Soils and Sediments》2008,8(2):74-79
Background, Aim and Scope The toxicity of contaminated sediments should be evaluated considering the direct exposure of laboratory organisms to whole
sediments and the indirect exposure to elutriates or extracts (Tay et al. 1992, Byrne and Halloran 1999, Nendza 2002). The
alga Dunaliella tertiolecta is indicated for the use in toxicity bioassays because it is highly sensitive to several xenobiotics. Harpacticoid copepods
have been already used for toxicity testing and Tigriopus fulvus is a promising Mediterranean target-species in ecotoxicology (Todaro et al. 2001, Faraponova et al. 2003, Pane et al. 2005a).
In this study, the toxicity of sediments collected in harbour sites of the Northeastern Adriatic Sea was evaluated by growth
inhibition test with free living and alginate-immobilized Dunaliella tertiolecta and acute toxicity test with nauplii and adult Tigriopus fulvus with the aim of pointing out the importance to utilize model organisms from different trophic levels in sediment ecotoxicology.
Methodology Elutriates and whole sediments were tested on free living and immobilized (Pane et al. 1998) algal cells, and on laboratory
reared copepods. Free-living D. tertiolecta were exposed to diluted elutriates in a static, multi-well plate system. Naalginate immobilized D. tertiolecta were placed in polystyrene inserts fitted with polyester mesh bottoms and exposed to a thin layer (2 mm) of whole sediments
in multi-well plates (EPS 1992, Pane and Bertino 1999). Toxicity tests with copepods were carried out on Tigriopus fulvus nauplii (elutriates) and adults (whole sediments and elutriates). Same-aged nauplii useful for toxicity tests were obtained
by egg sac detaching and consequent hatching stimulation (Pane et al. 2006). Newborn nauplii (I–II stage) were exposed to
elutriates in multi-well plates provided with polystyrene inserts. Adult T. fulvus maintained in polystyrene inserts fitted with polyester mesh bottoms were placed in contact with a thin layer (2 mm) of whole
sediment placed on multi-well plate bottoms. All end-points were evaluated after 96 h.
Results In general, the effects increased with the increasing of elutriate concentration up to 50%; the stimulation or inhibition
of algal growth was statistically significant in comparison to the control. The inhibiting elutriates induced EC50 variations of algal growth ranging from 66.9% to 74.3%. The mortality of T. fulvus nauplii was always < 25% after treatment with 100% elutriates and < 10% after treatment with 50% dilution; no effect was
shown up with 25% dilution; therefore LC50 was not calculable. The effect of elutriates was negligible on adult copepods and LC50 values were never calculable; percent mortality always resulted in < 10% after treatment with whole sediments.
Discussion Both experimental systems gave substantially similar results after exposition to whole sediments and elutriates. During the
experiment with algal cells, the immobilization in Na-alginate and the employment of inserts which allowed the contact of
organisms with sediments and their easy counting were particularly useful. Likewise, the employment of inserts of adequate
mesh size in the tests with copepods allowed the contact of organisms with the sediment and made organism handling and counting
easy, as well as the evaluation of mortality. The methodology here described and the utilization of the proposed test-species
could have an importance also considering that the current trend in ecotoxicological research is towards finding the most
appropriate organism for specific areas of concern by using indigenous species (Mariani et al. 2006) and towards the major
significance of chronic and reproductive end-points.
Conclusions Based on the above results, it can be stated that the bioassay with Dunaliella tertiolecta could be a good estimation tool for the ecotoxicological assessment of marine sediments. The immobilization of algae in Na-alginate
was seen to be useful to evaluate the toxicity of whole sediments; the employment of polystyrene inserts allowed an improvement
of the procedures. T. fulvus nauplii and adults, as other harpacticoids such as Tigriopus japonicus (Yoon et al. 2006), satisfy the basic criteria for the employment of a standard species in marine bioassays. To date only
pelagic Acartia tonsa are utilized in the standardized procedure to evaluate the risk assessment of chemicals or wastewaters (ISO 1999). As, on
the contrary, the exposure of copepods to solid-phase contaminants it is not yet standardized, the employment of polystyrene
inserts improved the procedures for T. fulvus too. So, the rapidity and the possibility to solve practical problems could be the main attractive features of this technique
(Pane et al. 2005a) when applied to whole sediments.
Recommendations and Perspectives The methodology here developed being also applicable to long term and reproduction tests should be recommended because it
provides relevant information in comparison with other frequently applied, standardized biotests with crustaceans (ISO 1999).
The procedure has been shown to be easily applicable to selected marine organisms.
ESS-Submission Editor: Prof. Dr. Henner Hollert (henner.hollert@bio5.rwth-aachen.de) 相似文献
993.
A wild tetraploid oat Avena maroccana Gdgr. was collected from the 11 populations in the periphery of Rommani and Casablanca geographic groups of Morocco. Genetic
diversity of the species was investigated using six allozyme systems. Allelic frequencies were scored representing eight polymorphic
and five monomorphic loci. Coefficient of gene differentiation (Gst) was 0.3019, which indicated great genetic differentiation. The number of alleles per locus was 2.6154, the percentage of
polymorphic loci was 61.54, and the expected heterozygosity was 0.2462 in all populations. Genetic diversity in A. maroccana was high in comparison to self-pollinated species. In total, nine heterozygotes resulting from outcrossing were found in
the progeny from M1, M3, M4, M22 and M26. The population of M7 had peculiar alleles Pgd–2SS and Pgd-1SS in high frequency. M9 had the lowest level of diversity out of the 11 populations. Geographic and genetic distances between
all the populations were not significantly correlated with each other (r = 0.0996). Cluster analysis showed that two groups, (M1, M22, M2 and M4) and (M3, M23, M8, M5 and M26) were apparently differentiated.
Two populations of the Casablanca group, M7 and M9 were independent from each other, and were separated distinctly from the
other populations. Genetic diversity of the Rommani and Casablanca groups was almost the same in all the parameters. This
was due to the similar man-made habitat such as roadside or rich fertile soil and brown clay soils. The population size of
A. maroccana was small and restricted to the narrow central Morocco with great genetic differentiation so that genetic diversity may be
reflected from the results of genetic drift and outcrossing heterozygote segregation. 相似文献
994.
Shahla Hosseini Bai Timothy J. Blumfield Zhihong Xu Chengrong Chen Clyde Wild 《Journal of Soils and Sediments》2012,12(3):386-395
Purpose
There is considerable interest in finding a cost-effective method of site preparation that effectively controls weeds during planting and further reduces the need for recurring herbicide applications. In this study, two weed control methods, herbicide and scalping, were examined. Both methods may have implications for soil organic matter (SOM) dynamics and nitrogen (N) which could consequently affect plant survival and vegetation establishment. This study aimed to investigate the dynamics of SOM, carbon (C) and N pools under site manipulation practices and the associated early plant survival and growth in tropical Australia. 相似文献995.
Daniela Gargano Nunzia Scotti Alessandro Vezzi Alessandra Bilardi Giorgio Valle Stefania Grillo Salvatore Cozzolino Teodoro Cardi 《Genetic Resources and Crop Evolution》2012,59(3):419-430
The plastome sequence of the European cultivated potato, Solanum tuberosum subsp. tuberosum (tbr, GenBank accession no. DQ386163), was compared with that of S. bulbocastanum, a wild potato relative (blb, GenBank accession no. DQ347958), in order to characterize the degree and type of variability
in different genomic regions, and develop molecular markers relevant to genetics, breeding and biotechnology of potato. One
hundred forty-two and 251 PICs (Potentially Informative Characters) were found in coding and non-coding sequences (NCSs),
respectively. Further, while variation in coding regions was almost exclusively due to nucleotide substitutions, 25% of PICs
in NCSs of tbr and blb were due to indels, most of them mononucleotide or longer tandem repeats (micro and minisatellites).
Four intergenic regions were selected for further analyses in other 16 tuber-bearing Solanum species. The rps16-trnQ
UUG
gene spacer was found to be the most variable, forty-six PICs in this region distinguishing 18 haplotypes. Analysis of haplotype
relationships, based on variability in the four intergenic regions, confirmed that the most primitive species from Central
America were the most distant to S. tuberosum. Finally, polymorphic sites in the same regions were used to develop a set of CAPS (Cleaved Amplified Polymorphic Sequences)
markers for species/cytoplasm identification in Solanum spp. 相似文献
996.
Watchareewan Jamboonsri Timothy D. Phillips Robert L. Geneve Joseph P. Cahill David F. Hildebrand 《Genetic Resources and Crop Evolution》2012,59(2):171-178
Chia, Salvia hispanica L., was well developed into a cultivated crop and an important component of Mesoamerican cultures and nutrition. Early Mesoamerican
breeders produced lines with well developed agronomic characteristics including good, uniform seed yield and retention. Seed
retention in particular is disadvantageous for survival in the wild. Maize, beans and squash were developed into important
crops concomitant with chia in Mesoamerica but unlike these other crops lack of photoperiodic variability in floral induction
limited the spread of chia cultivation into North America. There has been renewed interest in chia as an excellent source
of ω3 fatty acids and dietary fiber for healthy diets. Such highly unsaturated oils also are useful starting materials for
many renewable chemicals. Further we find chia grows very well in Midwestern and Eastern USA but flowers too late in the season
for seeds to mature before killing frosts. We set out to develop the genetic diversity in floral induction to provide germplasm
for production in the US and other temperate areas of the world. We demonstrate that new early flowering lines are able to
flower under a photoperiod of 15 h under greenhouse conditions. In field conditions, some selected new lines flowered at a
photoperiod of 14 h and 41 min during the 2009 growing season in Kentucky and can produce seeds in a range of environments
in temperate areas. 相似文献
997.
The Effectiveness and Feasibility of Using Ochre as a Soil Amendment to Sequester Dissolved Reactive Phosphorus in Runoff 总被引:1,自引:0,他引:1
Owen Fenton Laura Kirwan Daire Ó hUallacháin Mark Gerard Healy 《Water, air, and soil pollution》2012,223(3):1249-1261
Incidental losses of dissolved reactive phosphorus (DRP) to a surface waterbody originate from direct losses during land application
of fertilizer, or where a rainfall event occurs immediately thereafter. Another source is the soil. One way of immobilising
DRP in runoff before discharge to a surface waterbody, is to amend soil within the edge of field area with a high phosphorus
(P) sequestration material. One such amendment is iron ochre, a by-product of acid mine drainage. Batch experiments utilising
two grassland soils at two depths (topsoil and sub-soil), six ochre amendment rates (0, 0.15, 1.5, 7.5, 15 and 30 g kg−1 mass per dry weight of soil) and five P concentrations (0, 5, 10, 20 and 40 mg L−1) were carried out. A proportional equation, which incorporated P sources and losses, was developed and used to form a statistical
model. Back calculation identified optimal rates of ochre amendment to soil to ameliorate a specific DRP concentration in
runoff. Ochre amendment of soils (with no further P inputs) was effective at decreasing DRP concentrations to acceptable levels.
A rate of 30 g ochre kg−1 soil was needed to decrease DRP concentrations to acceptable levels for P inputs of ≤10 mg L−1, which represents the vast majority of cases in grassland runoff experiments. However, although very quick and sustained
metal release above environmental limits occurred, which makes it unfeasible for use as a soil amendment to control P release
to a waterbody, the methodology developed within this paper may be used to test the effectiveness and feasibility of other
amendments. 相似文献
998.
Ying Yan Dandan Lu Hao Zhou Haiping Hou Ting Zhang Laiming Wu Lankun Cai 《Water, air, and soil pollution》2012,223(3):1275-1280
A polyaniline-modified quartz crystal microbalance (QCM) sensor was obtained through immobilizing the polyaniline film on
the silver electrode surface of quartz crystal resonator by an electrochemical method. The sensor was studied for detecting
the formic acid gas of different concentrations, and the results showed that the resonant frequency of QCM decreased quickly
in the beginning and tended to be constant in the end when exposed to formic acid gas. The frequency shifts decreased faster
as the concentration of formic acid gas increased. And the frequency shifts of the QCM sensors were found to be linearly related
to the concentration of formic acid gas, which might be used to estimate the concentration level of the formic acid gas within
the range of experimental concentrations. The result of on-line monitoring test fully indicated that the QCM sensor responded
effectively to the increasing concentration of formic acid and had important practical significance and broad application
prospect in real-time detection of antique conservation environment in the museum. 相似文献
999.
Ali Sdiri Teruo Higashi Rochdi Chaabouni Fakher Jamoussi 《Water, air, and soil pollution》2012,223(3):1191-1204
A batch sorption method was used to study the removal of few toxic metals onto the Late Cretaceous clays of Aleg formation
(Coniacian–Lower Campanian system), Tunisia, in single, binary and multi-component systems. The collected clay samples were
used as adsorbents for the removal of Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solutions. Results show that the natural
clay samples were mainly composed of silica, alumina, iron and magnesium oxides. N2-adsorption measurements indicated mesoporous materials with modest specific surface area of <71 m2/g. Carbonate minerals were the most influencing parameters for heavy metal removal by natural clays in both single and multi-element
systems. The affinity sequence was Pb(II)>Cu(II)>Zn(II)>Cd(II) due to the variable physical properties of the studied metals.
The maximum adsorption capacity reached 131.58 mg/g in single systems, but decreased to <50.10 mg/g in mixed systems. In single,
binary and muti-element systems, the studied clay samples removed substantial amounts of heavy metals, showing better effectiveness
than the relevant previous studies. These results suggest that the studied clay samples of the Late Cretaceous clays from
Tunisia can be effectively used as natural adsorbents for the removal of toxic heavy metals in aqueous systems. 相似文献
1000.
Carla M. Koretsky Andrew MacLeod Ryan J. Sibert Christine Snyder 《Water, air, and soil pollution》2012,223(3):1415-1427
Redox stratification, especially hypolimnetic anoxia resulting from eutrophication, and salinization resulting from application
of salts for road deicing is investigated in three kettle lakes in southwest Michigan. Two of the lakes (Asylum and Woods
Lakes) are located in urban Kalamazoo, Michigan, and the third (Brewster Lake) is located in rural Hastings, Michigan. In
summer, the water columns of all three lakes are distinctly redox stratified, with anoxic hypolimnia and significant accumulation
of reduced solutes (e.g., Mn(II), Fe(II), ammonia) in the lake bottom waters. Extremely elevated conductivity, chloride, sodium,
and potassium levels are observed in the urban Asylum and Woods Lakes compared to the rural Brewster Lake, presumably due
to runoff of road salt deicers applied in the surrounding watershed. These significant changes in water quality are of concern
because they may detrimentally impact lake mixing, biodiversity, and ecosystem function in the urban lakes. 相似文献