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991.
3,4-Dimethylpyrazole phosphate (DMPP) – a new nitrification inhibitor for agriculture and horticulture 总被引:16,自引:0,他引:16
Wolfram Zerulla Thomas Barth Jürgen Dressel Klaus Erhardt Klaus Horchler von Locquenghien Gregor Pasda Matthias Rädle Alexander Wissemeier 《Biology and Fertility of Soils》2001,34(2):79-84
3,4-Dimethylpyrazole phosphate (DMPP) is a new nitrification inhibitor with highly favourable properties. It has undergone thorough toxicology and ecotoxicology tests and application-technology experiments, and has been shown to have several distinct advantages compared to the currently used nitrification inhibitors. Application rates of 0.5-1.5 kg ha-1 are sufficient to achieve optimal nitrification inhibition. DMPP can significantly reduce NO3- leaching, without being liable to leaching itself. DMPP may reduce N2O emission, apparently without a negative effect on CH4 oxidation of the soil. The use of DMPP-containing fertilizers can improve yield. This offers the possibility of saving mineral fertilizer N, reducing the number of N-application rounds, and obtaining higher crop yields with current fertilizer-N rates. 相似文献
992.
Gert Poulsen Claus Holten Roland von Bothmer 《Genetic Resources and Crop Evolution》2007,54(5):1105-1115
Dead seeds of a fodder beet cultivar ‘Elvetham’ stored under ambient conditions since 1880 were compared to a homonymous sample
preserved in an on-farm situation in Denmark. DNA was isolated from single seeds and successfully applied to Amplified Fragment
Length Polymorphism (AFLP) analysis of the accessions. Six primer pairs were used to determine the similarity between the
two accessions based on 112 polymorphic bands. Furthermore, similarity among seven cultivars of fodder beets representing
the main types used in Scandinavia at the end of the 19th century was determined. This analysis was based on 152 polymorphic
bands. Differentiation among the seven cultivars was determined to a mean G
ST value of 0.438, while G
ST between the two ‘Elvetham’ accessions was 0.266. A principal coordinate analysis based on jaccards similarity index illustrates
that the two ‘Elvetham’ accessions are different from each other. The differentiation is higher than the value found between
two separate ‘Eckerndorfer’ accessions. The results indicate that the cultivated accession has changed. Additionally, the
value of applying old dead seed material for documentation in gene banks is demonstrated.
During the analysis it was found that DNA isolated from seeds and leaves behaved differently in the AFLP process, however,
the two fractions assigned to their common accession. 相似文献
993.
A research program concerning the seedbed preparation problems in Swedish agriculture included a series of pot experiments in shallow plastic boxes. Seedbeds of well-defined characteristics were arranged, and seedling emergence was determined by daily plant countings. In the experiments reported, the main subject of study was the efficiency of the seedbed in controlling evaporation. Clay or clay loam soils were used, and the crops were mainly small grain cereals.Seven experiments with unstratified seedbeds showed that for small grains in a dry weather situation, the seed should be placed directly onto the moist bottom of a harrowed layer, which should be 4–5 cm deep and mainly consist of aggregates smaller than 4 mm. If the bottom layer contains less than 5% plant available water, or if a fine enough seedbed structure cannot be produced, the depth of both harrowing and sowing should be increased. In four experiments with stratified seedbeds, no reasons were found for sorting the coarse aggregates to the soil surface, provided the initial moisture content increased with depth.Effects of seed quality were studied in two experiments. Seed lots with equal germinability under optimum moisture conditions gave large differences in emergence in a moisture stress situation. Within a rather wide seed size range, the size as such had only minor influence on the emergence rate. 相似文献
994.
A new selective and highly sensitive medium was developed for isolation of Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial canker of tomato, from seed and latently infected plants. The new medium (BCT) proved to be superior to all published semiselective media for Cmm and is denoted as selective medium because of (i) its mean plating efficiency, amounting to ≤89% within 7 days for all 30 Cmm strains from different sources tested; (ii) the high selectivity, because accompanying bacterial species occurring on tomato plants and seed or bacteria obtained from culture collections were inhibited to an extent of 98 to 100%; and (iii) the remarkable detection sensitivity. Thus, 8 CFU of Cmm in field plant homogenates containing 12,750 CFU of accompanying saprophytes were detected on BCT. Under these extreme conditions, all of the published semiselective media (D2, KBT, D2ANX, SCM, mSCM, CMM1, mCNS, and EPPO) gave false-negative results. Either some media were rather toxic and Cmm growth was also inhibited or the other, less toxic media allowed growth of high numbers of saprophytes, so that Cmm growth was suppressed. Exclusively, BCT also supported growth of the closely related C. michiganensis subsp. insidiosus, nebraskensis, and tessellarius. The new medium is recommended for Cmm detection in tomato seed, and in symptomless tomato plantlets, to improve disease control of bacterial canker of tomato. 相似文献
995.
996.
Eric de Deckere Ward De Cooman Vicky Leloup Patrick Meire Claudia Schmitt Peter C. von der Ohe 《Journal of Soils and Sediments》2011,11(3):504-517
Purpose
The development of Sediment Quality Guidelines (SQGs) is one of the remaining challenges for a better protection of aquatic biodiversity and in particular sediment dwelling organisms. So far, sediment quality assessment in Flanders was based on a comparison of chemical concentrations to the geometric mean of the concentrations at 12 reference sites. The study described in this paper addressed the need for more science-based guidelines. The developed guidelines are already incorporated into Flemish legislation. 相似文献997.
Jörgen Rudolphi Alexandro CarusoMaria von Cräutlein Sanna Laaka-LindbergRiitta Ryömä Håkan Berglund 《Forest Ecology and Management》2011,261(11):1911-1918
The interest in harvesting logging residues in the form of stumps has recently increased markedly in the Nordic countries of Europe due to the steadily growing market for bio-fuel from forestry. Yet, stumps are currently harvested without a solid knowledge of their importance for forest organisms. To assess the relative importance of thinned, clear-cut, and burned clear-cut stands for the diversity of bryophytes on stumps we investigated bryophyte species composition and richness on 755 spruce stumps in 27 forest stands in southern-boreal Finland. Stumps were sampled within both wet and dry sites. For comparison we also surveyed bryophytes on 669 ground plots in the same stands to assess if patterns were consistent regardless of substrate type.Stand type (i.e. thinned, clear-cut, or burned clear-cut) was the main predictor of both species richness and composition on stumps. Stumps in thinned stands were more species rich than in clear-cuts, and the lowest richness was found on stumps in burned clear-cuts. Differences in species composition were explained by higher frequency of occurrence of species in thinned than in clear-cut stands. Thus, stumps in clear-cut stands tended to host a subset of species from the thinned stands, but there was also a pattern of turnover where different species were present in thinned and clear-cut stands, respectively. The results were similar for bryophytes on ground indicating that canopy cover strongly affected the diversity of bryophytes regardless of substrate.We conclude that stump harvest in open, clear-cut stands will probably have minor effects on bryophyte diversity on dead wood in the managed forest landscape. Conservation efforts in thinned stands (e.g. retention and creation of dead wood) may be important for promoting the diversity of bryophytes in managed forests. 相似文献
998.
999.
Christoph von Horst 《Anatomia, histologia, embryologia》2019,48(6):577-583
Vacuum forced tissue impregnation is the signature step of the plastination process. It requires polymers with a low vapour pressure, low viscosity and a long pot life. Plastination polymers are a compromise between these mandatory requirements on the one hand and various secondary demands such as specimen stability, resistance to UV light and defined light refraction index on the other hand. Combining different polymers in one plastinate instead of using one plastination polymer alone can result in improved specimens for exhibitions and teaching including hands‐on use for students. The aim of this study was to assess the range of possible sheet plastinate modifications and how the resulting multiple polymer plastinates can fulfil the secondary requirements of user‐friendly plastinates. Adding sub‐steps of tissue impregnation and processing to the standard plastination protocol allows combining different polymer properties including the use of substances which are not suitable for conventional plastination as such but have better properties than plastination polymers. Advantages like resistance to UV light and mechanical stability can be combined and characteristic disadvantages of plastination polymers can be avoided. Acrylic protection layers (APL) offer a complete protection of the specimen in combination with advanced presentation possibilities and the option of completely refurbishing valuable specimens. Hybrid sheet plastinates provide lower preparation cost and polymer–tissue interactions for an improved visualization of fat, nerves and brain tissue. Selective impregnation is a promising approach for the clearer differentiation of various structures and tissue types. 相似文献
1000.
Müller R Schwartzkopf-Genswein KS Shah MA von Keyserlingk MA 《Journal of animal science》2008,86(5):1215-1222
The use of the neck region as an injection site in cattle is becoming routine. Use of a blind may reduce aversive behavior caused by the presence of the person administering the injection. To evaluate whether cattle react to the proximity of the stockperson or to the actual injection, one hundred twenty 10-mo-old Angus steers (298 +/- 28 kg of BW; mean +/- SD) were assigned to 1 of 4 treatment groups using a partial crossover design (neck/sham injection x blind/no blind) replicated over 2 d (3 d apart). Steers were restrained for a total of 60 s in a squeeze chute, with treatment being administered 20 s after entry. Animal reactivity was rated using 2 scoring methods, including a visual and an electronic score, for three 20-s intervals (pre-treatment, treatment, and posttreatment intervals). Flight speed (m/s) was used as a measure of aversion to the treatments and was taken upon release from the chute. No interactions (P > 0.10) were observed between the blind and injection treatments for any of the measurements taken. No treatment or day effect on flight speed (2.7 vs. 2.6 m/s; P > 0.03) was observed; however, the correlation between days (r = 0.74; P < 0.001) was significant. Visual scores indicated that injected steers were more agitated during the treatment interval than were the sham injected steers (1.9 vs. 1.6, respectively; P = 0.01). However, no differences (P > 0.10) were found between injection and sham injection treatments for any of the electronic scores. Steers exposed to the blind had lower electronic reactivity scores (P < 0.05) than those not exposed to the blind, which was in contrast to the results obtained for the visual scores (P < 0.05). Discrepancies between reactivity scores may be due to the difficulty of accurately assessing minor animal responses using the visual method. The presence of a handler during an injection procedure could be a contributor to the aversion response observed in cattle undergoing routine neck injections, and use of a blind helped to reduce the reactivity of the steers. 相似文献