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排序方式: 共有502条查询结果,搜索用时 15 毫秒
101.
Franziska Löschenberger Andreas Fleck Heinrich Grausgruber Herbert Hetzendorfer Gerhard Hof Julia Lafferty Marion Marn Anton Neumayer Georg Pfaffinger Johann Birschitzky 《Euphytica》2008,163(3):469-480
Breeding for organic agriculture (BFOA) is a strategy for a commercial breeding company based on the exploitation of the frequently
observed high correlation for many traits between conventional, low input (LI) and organic agriculture (ORG). Indirect selection
under LI can be useful to roughly divide the germplasm into the genotypes better adapted to high input and those better adapted
to LI or ORG conditions. BFOA is an evolving process, in which two methods are currently applied: early generations are either
selected following the pedigree system under LI, or grown as bulk populations on ORG fields. In the latter case the system
switches to LI after individual ear selection under ORG conditions. In both methods, the first replicated yield trial is grown
parallel under ORG and LI. Subsequently, the genotypes are grouped into conventional or ORG advanced trial series. The BFOA
strategy allows that the larger genetic variability of both the organic and conventional gene pool can be exploited in the
selection for ORG. Hitherto, seven winter wheat varieties were released in Austria after exclusive organic VCU testing. 相似文献
102.
103.
Identification of Wheat Powdery Mildew Resistance Genes by Analysing Host-Pathogen Interactions 总被引:1,自引:0,他引:1
Fifty-nine winter wheat cultivars and thirteen lines possessing known powdery mildew resistance genes were inoculated with eleven different isolates. By comparing their resistance patterns the responsible major resistance genes of the above-mentioned cultivars have been determined. The so-called “Blaukorn” resistance is conditioned by gent Pm4b. The resistance patterns of Ml-i and Pm5 being similar, the relationship between them has to be analysed by segregating populations. 相似文献
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107.
Susanne Riede Carola Lindig Hansjrg Abel Bettina Tonn Johannes Isselstein Gerhard Breves 《Journal of animal physiology and animal nutrition》2019,103(2):436-446
According to climate change scenarios, central Europe may expect extending drought periods during summer. Lower water availability may influence the ruminal digestion of individual forage legume species differently. To test this hypothesis, Lotus corniculatus L. (var. Bull), Medicago lupulina L. (var. Ekola), Medicago falcata L. (wild seeds) and Trifolium repens L. (var. Rivendel) were each grown in parallel lots of control and drought‐stressed monocultures. Rainout shelters (installed in May 2011 on a regrowth after first cut until harvest in mid of June) withheld rainfall of 40 mm in the drought stress treatment. Samples of dried (60°C) and milled (5 mm screen) forage legumes were incubated in a simulation experiment using Rusitec to assess drought effects on parameters for microbial metabolism. Degradability of dry matter and organic matter as well as methane production decreased in incubations with drought‐stressed compared to control variants of legume species. Degradability of crude protein, neutral detergent fibre, acid detergent fibre and residual organic matter including non‐fibre carbohydrates and lipids were affected by interactions between drought stress and species. Significant interactions were also found for ammonia concentrations, molar SCFA proportions and the microbial communities. It is concluded that drought stress for growing forage legumes influences their ruminal degradation and fermentation as well as the ruminal microbial communities of Bacteria and Archaea differently in a legume species‐dependent manner. 相似文献
108.
Ulrich Meyer Kristin Weigel Friedrich Schne Matthias Leiterer Gerhard Flachowsky 《Livestock Science》2008,115(2-3):219-225
The aim of the present study was to assess the influence of different levels of iodine supplementation on animal growth and the iodine content of food from beef cattle. In a dose–response experiment with 34 growing fattening bulls of the “German Holstein” breed, in the range from 223 to 550 kg body weight, three iodine dosages were tested. The animals were fed a corn silage/concentrate ration. Iodine concentration in the diet amounted to 0.79 (Group 1), 3.52 (Group 2) and 8.31(Group 3) mg I per kg dry matter (DM). After slaughtering, I was determined in blood, serum, plasma, thyroid, liver, kidneys and meat (M. longissimus dorsi, M. glutaeus medius) by ICP-MS. I-supplementation did not significantly influence DM intake, daily weight gain (1453 (1), 1419 (2) and 1343 (3) g; p > 0.05) or slaughtering performance, but the weight of the thyroid gland increased significantly with the highest I dosage (32 (1), 26 (2) and 42 (3) g animal− 1, p < 0.05). I-supplementation significantly increased I-concentration in muscle, liver, kidney and thyroid gland (p < 0.05). The contribution of beef food to I-intake of humans is relatively low, therefore there is no need to reduce the EU-upper limit (10 mg kg− 1 feed) for growing fattening cattle from the view of consumer safety. In view of animal health and performance more dose–response studies seem to be necessary. 相似文献
109.
Weighing lysimeters are valuable devices for measuring water‐balance components with high temporal resolution and high accuracy. However, some older lysimeter facilities still operate with lever‐arm‐counterbalance weighing systems that are sensitive to disturbances, e.g., forces exerted by wind. Filtering and averaging are commonly used for processing noisy raw data. We studied some data of a lever‐arm weighing system and performed additional experiments in order to (1) determine the measurement accuracy of the current weighing scheme (facility, and measuring and averaging procedure) regarding wind effects, (2) describe the oscillation behavior, (3) test the mechanical performance of the system, and (4) adapt the averaging procedure with respect to improved interpretation of the weighing data. The measurement accuracy for a wind velocity < 5 m s–1, measured in 10 m height, was ≈ ± 0.4 kg (equivalent to ± 0.14 mm); at a higher wind velocity, the accuracy was three times lower, but there was no linear relationship. Additional experiments showed that the weighing system is oscillating with more or less irregular amplitudes. A loading–unloading experiment delivered proper results of the measured loads. The mechanical system reacted immediately, and no directional effects were found. However, small changes of < 1 kg could hardly be determined due to the oscillations. A time series of raw data measured every 2 s served as basis for improving the averaging method. A moving average from 64 values was computed representing the currently used method, and serving as reference. With this procedure an accuracy of ± 0.38 kg could be reached. Averaging 150 values led to an accuracy of ± 0.28 kg (0.1 mm) for a wind velocity < 5 m s–1. 相似文献
110.