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991.
Andre Luiz Biscaia Ribeiro da Silva Daniel Tucker Price Abolfazl Hajihassani Juan Carlos Diaz-Perez Elizanilda Ramalho do Rego 《Communications in Soil Science and Plant Analysis》2020,51(13):1826-1833
ABSTRACT Root-knot nematodes (RKN; Meloidogyne spp.) cause enormous yield reductions in vegetable crops. While nematicides are the most effective method for controlling RKN in carrot (Dacatus carota), the efficacy of non-fumigant nematicides, compared to fumigants, is still not fully understood. The objective of this study was to evaluate the effect of 1,3-dichloropropene, a fumigant nematicide, and fluensulfone, a non-fumigant nematicide, on RKN control and yield of fresh market and processing carrot. Field experiments were conducted in a commercial farm in Lenox, GA. A randomized complete block design (r = 4) was used in a factorial arrangement of 3 nematicide treatments and 2 carrot cultivars. Nematicide treatments were the application of 1,3-dichloropropene, fluensulfone, and untreated control. Carrot cultivars were Baltimore (fresh marketing) and Belgrado (processing). In general, RKN population was low early season, averaging 0.8 RKN 100 cm?3 of soil. RKN populations increased with crop development and there were significant differences among nematicide treatments. At harvest, RKN populations were lower for fluensulfone (1.1 RKN 100 cm?3 of soil) and 1,3-dichloropropene (3.2 RKN 100 cm?3 of soil) compared to Control (26.4 RKN 100 cm?3 of soil); however, fluensulfone (91,278 kg ha?1) had higher yield than 1,3-dichloropropene (64,154 kg ha?1) and Control (61,908 kg ha?1). Carrot cultivars were similar for RKN population and yield. Overall, the non-fumigant nematicide was more beneficial for carrot production than the fumigant nematicide. 相似文献
992.
Fernando Shintate Galindo Marcelo Carvalho Minhoto Teixeira Filho Salatiér Buzetti José Mateus Kondo Santini Eduardo Henrique Marcandalli Boleta Willian Lima Rodrigues 《Journal of plant nutrition》2020,43(8):1057-1069
AbstractNew studies are needed to optimize the nitrogen (N) amount that can be applied to utilize the Azospirillum brasilense benefits. In addition, information regarding the interaction between the urease inhibitor and biological nitrogen fixation (BNF) and how they affect the macronutrients accumulation are also needed. We evaluate the effect of N sources and doses associated with A. brasilense regarding the macronutrients accumulation in straw and grains and wheat grain yield in tropical conditions. A randomized block experimental design was used with four replications in a 2?×?5?×?2 factorial arrangement as follows: two N sources (urea and urea with urease enzyme inhibitor NBPT; five N doses (0, 50, 100, 150, and 200?kg ha?1) applied in topdressing; with and without A. brasilense inoculation. We found that an increase in N doses positively influenced the accumulation of macronutrients in straw and grains and the wheat grain yield. N sources have similar effects. Inoculation with A. brasilense increased accumulation of Mg and S in straw and P, Ca, and Mg in grains, regardless of the N dose. The inoculation with A. brasilense associated with 140?kg ha?1 of N increased wheat grain yield. The inoculation can contribute in a more sustainable way to wheat nutrition and optimizing N fertilization. 相似文献
993.
Carlos?Wildt Oriol?Gibert José?Luis?CortinaEmail author Giuliana?Coscera 《Journal of Soils and Sediments》2004,4(3):184-191
Goal, Scope and Background The remediation of heavy-metalcontaminated soils and sediments is of significant value to industrial areas around the world.
The spread of such pollutants can result in a potential risk of entering the groundwater system and being transported to potential
receptors. Leaching techniques can be an effective treatment option for the metal removal from soils and sediments. This approach
consists of washing or leaching the contaminated soil with an appropriate reagent and the subsequent treatment of the leaching
in an above-ground installation (on-site treatment) where metals can be removed and concentrated into a smaller volume. Among
the heavy metals, chromium is a commonly identified soil contaminant, particularly in sites with intensive economic activities
including agriculture, industrial, mining and mineral,processing.
Objective The objective of this work was the evaluation and development of a leaching process for the remediation of soils and sediments
polluted with chromium at laboratory scale. Chromium soil pollution was generated after the breakdown of a channel containing
chromium wastes from a tannery plant. The pollution extension has been estimated to be on the order of thousands of tonnes
of soil to be treated, with chromium contents ranging from 500 to 17,000 mg kg-1 soil.
Methods The whole process investigated in this study integrates three stages; a) chromium leaching from a sediment using a diluted
sulphuric acid solution, b) treatment of the leaching effluents with a magnesium oxide/limestone mixture for the precipitation
of chromium hydroxide after acidity neutralisation, and c) polishing step to remove the eventual remaining chromium by adsorption
onto natural zeolite. The amount of contaminated sediment treated ranged from 0.5 to 2 kg with chromium contents of between
2000 and 17,000 mg kg-1.
Results and Discussion The paper describes results on the performance of the process and the optimisation of steps including influence of acid sulphuric
concentration, chromium removal efficiency as well as alkaline reactive mixture proportions. Effluents from the leaching cells
showed a significant decay on the chromium concentration with the increase of leaching runs and a high content of acidity
(pH values close to 0.5). The treatment of these effluents in a second cell containing magnesium oxide/ limestone mixtures
resulted in a high efficiency in neutralisation of acidity (pH values around 7) and chromium removal (concentrations below
5 mg 1-1). The passage through a third compartment containing zeolite as an adsorbent decreased the chromium concentration below 0.5
mg 1-1,
Conclusions From the results obtained on the chromium leaching and immobilisation with magnesium oxide/limestone mixture at a laboratory
scale, it could be pointed out that: (a) diluted sulphuric acid solutions (3%) demonstrated a high efficiency on chromium
removal from sandy polluted soils on the kilogram scale, (b) mixtures of magnesium oxide/limestone demonstrated a high capacity
to neutralise the residual high acidity present on the effluents and to remove chromium by precipitation and (c) between the
limestone and caustic magnesia mixtures, those containing more than 60% of caustic magnesia provide the higher efficiency.
Recommendation and Outlook Future work would be directed to the evaluation of the integrated process of leaching and chromium precipitation on column
at a scale of 100 to 1000 kg. 相似文献
994.
Javier M. Gonzalez Douglas R. Smith Stan Livingston Elizabeth Warnemuende-Pappas Martha Zwonitzer 《Journal of Soils and Sediments》2016,16(7):1921-1932
Purpose
In a 6-year study, we investigated the effectiveness of blind inlets as a conservation practice in reducing pesticide losses compared to tile risers from two closed farmed depressional areas (potholes) in the US Midwest under a 4-year cropping rotation.Materials and methods
In two adjacent potholes within the same farm and having similar soils, a conventional tile riser and blind inlet were installed. Each draining practice could be operated independent of each other in order to drain and monitor each depression with either practice. Sampling events (runoff events) were collected from the potholes from 2008 to 2013 using autosamplers. The samples were analyzed for atrazine, metolachlor, 2,4-D, glyphosate, and deethylatrazine.Results and discussion
The results of this study demonstrated that the blind inlet reduced analyzed pesticide losses; however, the level of reduction was compound dependent: atrazine (57 %), 2,4-D (58 %), metolachlor (53 %), and glyphosate (11 %).Conclusions
Results from this study corroborate previous research findings that blind inlets are an effective conservation practice to reduce discharge and pollutants, including pesticides from farmed pothole surface runoff in the US Midwest.995.
Susheel Verma Jawahar L. Karihaloo Shailesh K. Tiwari Rani Magotra Awtar K. Koul 《Genetic Resources and Crop Evolution》2007,54(2):221-229
Eremostachys superba Royle ex Benth. (Lamiaceae) has undergone a severe decline in population size since its discovery in the North-western Himalayas
in late 19th century. One hundred and seventy-two plants from six populations in the Indian states of Uttar Pradesh and Jammu
& Kashmir, located between 0.45 km and 455.72 km apart from each other were evaluated for RAPD polymorphism. Sixteen random
primers generated 92 bands overall, 77 of which were polymorphic. Shannon’s index of genetic diversity within populations
(H
o) ranged between 0.305 and 0.421; the average within-population diversity (H
pop) was 0.389; and the total species diversity (H
sp) was 0.478. The population from Mohand (representing the type locality) had the fewest plants, at 18, and was genetically
the most depauperate. Among the other populations, ranging in size between 52 and 1,022 individuals, no relation between population
size and genetic diversity was evident. It is suggested that these six populations represent relics of a larger, extended
population, in which the presence of perennating rootstocks has helped preserve historic patterns of genetic diversity. AMOVA
revealed that 83.01% of the variation exists within populations, which was consistent with earlier studies on the reproductive
biology of E. superba, which indicated this species is predominantly allogamous. FST distances between all populations were significant, indicating
geographic differentiation despite some of them being closely separated. Habitat restoration and protection from indiscriminate
harvesting are proposed as primary strategies for conserving E. superba. Rejuvenation of the Mohand population through intrapopulation crossing between plants bearing diverse molecular phenotypes
is also suggested. 相似文献
996.
Xiao-Ping Jia Yun-Su Shi Yan-Cun Song Guo-Ying Wang Tian-Yu Wang Yu Li 《Genetic Resources and Crop Evolution》2007,54(2):233-236
The development of EST-SSR in foxtail millet (Setaria italica) for polymorphism and transferability study was reported here. From 1213 EST sequences, 30 SSRs were obtained and primers
were designed for 26 SSRs. Among them, four pairs of SSR primers amplified polymorphic products in 12 foxtail millet cultivars
and one accession of Setaria viridis, a wild relative of foxtail millet, with 10 alleles detected for the four loci and 2.5 alleles per locus. In addition, ten
SSR markers could be transferred to other nine Gramineae species. The putative functions of 11 ESTs containing polymorphic
and transferable SSRs were also identified. 相似文献
997.
In industrial areas, heavy metals may accumulate in forest soil organic horizons, affecting soil microorganisms and causing
changes in the chemical composition of the accumulated organic matter. The objectives of this study were to test the ability
of near-infrared spectroscopy (NIRS) to detect heavy metal effects on the chemical composition of forest soil O horizons and
to test whether NIRS may be used to quantitatively determine total and exchangeable concentrations of Zn and Pb (Znt, Pbt, Znex, Pbex) and other chemical and microbial properties in forest soil O horizons polluted with heavy metals. The samples of O horizons
(n = 79) were analyzed for organic C (Corg), total N and S (Nt, St), Znt, Pbt, Znex, Pbex, basal respiration (BR), microbial biomass (Cmic) and Cmic-to-Corg ratio. Spectra of the samples were recorded in the Vis-NIR range (400–2,500 nm). To detect heavy-metal-induced changes in
the chemical composition of O horizons principal components (PC1–PC7) based on the spectral data were regressed against Znt + Pbt values. A modified partial least squares method was used to develop calibration models for prediction of various chemical
and microbial properties of the samples from their spectra. Regression analysis revealed a significant relationship between
PC3 and PC5 (r = −0.27 and −0.34, respectively) and Znt + Pbt values, indicating an effect of heavy metal pollution on the spectral properties of the O horizons and thus on their chemical
composition. For quantitative estimations, the best calibration model was obtained for Corg-to-Nt ratio (r = 0.98). The models for Corg, Nt, and microbial properties were satisfactory but less accurate. NIRS failed to accurately predict St, Corg-to-St, Znt, Pbt, Znex, and Pbex. 相似文献
998.
Louise Willemen Xavier Scheldeman Víctor Soto Cabellos Simón Rafael Salazar Luigi Guarino 《Genetic Resources and Crop Evolution》2007,54(7):1599-1612
This study evaluates quantitatively the suitability of the use of site-specific socio-economic and environmental data as indicators
to rapidly assess patterns of diversity and genetic erosion risk in cassava. Socio-economic data as well as farmers’ estimation
of genetic erosion were collected in the study area, the Ucayali region of the Peruvian Amazon, through interviews with 285
cassava farmers in 50 communities, while diversity was assessed based on agromorphological characterization of 295 cassava
accessions. Using multivariate regression analyses, 50 and 45% of the variation in respectively diversity and genetic erosion
estimation could be explained by a selected set of socio-economic and environmental indicators. In both regression models
four out of the total of 38 variables proved to contribute significantly (at p < 0.10 level). Additionally, the study revealed that farmers are a good direct source of information on the diversity present
at community level, which can contribute to the development of methodologies to assess diversity more rapidly. The results
of this study are valuable for the development of models to rapidly assess diversity dynamics in large areas. 相似文献
999.
Verónica Nilda Ispizúa Irma Rosana Guma Sergio Feingold Andrea Martina Clausen 《Genetic Resources and Crop Evolution》2007,54(8):1833-1848
Andean potato varieties are cultivated in the northwest of Argentina and constitute the most important staple food for the
local farmers. The genetic diversity of 155 accessions conserved at the Genebank of Balcarce (INTA) was tested using four
microsatellites. Three commercial potato varieties of Tuberosum group and one accession of Curtilobum group were used as outgroups.
The presence of bands was scored for each microsatellite and for each accession and the data were analysed by principal coordinate
analysis. The polymorphism information content was obtained for each molecular marker from banding patterns. Analysis of molecular
variance was carried out with a variable number of accessions for each landrace, from different departments and sites within
departments. More than one genotype was detected in the majority of the potato landraces. Some accessions within each landrace
did not differentiate. AMOVA revealed that most of the genetic variation occurred among sites within departments and among
local varieties. These findings are discussed considering the agricultural practices carried out in the Andean farming system. 相似文献
1000.
N. P. S. Dhillon R. Ranjana Kuldeep Singh I. Eduardo A. J. Monforte M. Pitrat N. K. Dhillon P. P. Singh 《Genetic Resources and Crop Evolution》2007,54(6):1267-1283
Diversity among 36 snapmelon landraces, collected from 2 agro-ecological regions of India (9 agro-climatic sub-regions), was
assayed using RAPD primers, morphological traits of plant habit and fruit, 2 yield-associated traits, pest and disease resistance
and biochemical composition (TSS, ascorbic acid, titrable acidity). Typical differences among accessions were observed in
plant and fruit characteristics and snapmelon germplasm with high titrable acidity and possessing resistance to downy mildew,
Cucumber mosaic virus, Zucchini yellow mosaic virus, Papaya ringspot virus, Aphis gossypii and Meloidogyne incognita was noticed in the collection. RAPD based grouping analysis revealed that Indian snapmelon was rich in genetic variation
and region and sub-region approach should be followed across India for acquisition of additional melon landraces. Accessions
of var. agrestis and var. momordica clustered together and there was a separate cluster of the accessions of var. reticulatus. Comparative analysis of the genetic variability among Indian snapmelons and an array of previously characterized reference
accessions of melon from Spain, Israel, Korea, Japan, Maldives, Iraq, Pakistan and India using SSRs showed that Indian snapmelon
germplasm contained a high degree of unique genetic variability which was needed to be preserved to broaden the genetic base
of melon germplasm available with the scientific community.
N. P. S. Dhillon and Ranjana contributed equally to this work and are considered the first authors. 相似文献