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681.
682.
Duncan McGregor 《Land Degradation \u0026amp; Development》1990,2(4):325-327
683.
Ru-Qiang Xu Norihiko Tomooka Duncan A. Vaughan Koji Doi 《Genetic Resources and Crop Evolution》2000,47(2):123-134
The present study, using RAPD analysis, was undertaken to characterize genetic variation in three forms of V. angularis, cultivated, wild and weedy forms, and their relationships. The materials used consisted of 171 individuals (plants) or cultivars from 23 populations including 5 wild populations, 6 weedy populations, 6 cultivated populations and 6 populations with plants having wild and weedy or intermediate morphology, denoted here as complex populations. The materials used were collected on Honshu Island, Japan and seeds collected directly from the field were germinated for DNA extraction. In addition, 6 landrace accessions of V. angularis from the genebank were also analyzed. Genetic variation was highest in the wild form (Hg= 0.132; GD = 0.388), followed by the weedy form (Hg= 0.124; GD = 0.341) and the least in the cultivated form (Hg= 0.079; GD = 0.274). Intra-population genetic variation was high in the weedy and in the wild populations. However, inter-population was greater than intra-population genetic variation for all groups of populations studied in the V. angularis complex. 93% of the total diversity in the present study was exhibited by plants from complex populations and specific RAPD bands were found in these populations. Our results provide evidence that complex populations would be a logical focus for efforts to conserve the V. angularis complex in situ. Our results suggest that weedy populations are usually an ecotype of the wild form adapted to a different habitat. 相似文献
684.
Kefeng Zhang Duncan J. Greenwood Clive R. Rahn Philip J. White 《Agricultural Water Management》2010,97(10):1411-123
Agro-hydrological models have widely been used for optimizing resources use and minimizing environmental consequences in agriculture. SMCR_N is a recently developed sophisticated model which simulates crop response to nitrogen fertilizer for a wide range of crops, and the associated leaching of nitrate from arable soils. In this paper, we describe the improvements of this model by replacing the existing approximate hydrological cascade algorithm with a new simple and explicit algorithm for the basic soil water flow equation, which not only enhanced the model performance in hydrological simulation, but also was essential to extend the model application to the situations where the capillary flow is important. As a result, the updated SMCR_N model could be used for more accurate study of water dynamics in the soil-crop system. The success of the model update was demonstrated by the simulated results that the updated model consistently out-performed the original model in drainage simulations and in predicting time course soil water content in different layers in the soil-wheat system. Tests of the updated SMCR_N model against data from 4 field crop experiments showed that crop nitrogen offtakes and soil mineral nitrogen in the top 90 cm were in a good agreement with the measured values, indicating that the model could make more reliable predictions of nitrogen fate in the crop-soil system, and thus provides a useful platform to assess the impacts of nitrogen fertilizer on crop yield and nitrogen leaching from different production systems. 相似文献
685.
Over the last two decades transgenic plants have moved from being solely laboratory vehicles for basic research work to providing new varieties grown on large areas throughout the world.…… 《分子植物育种》2007,5(2):273
Over the last two decades, transgenic plants have moved from being solely laboratory vehicles for basic research work to providing new varieties grown on large areas throughout the world. 相似文献
686.
CH. Iben 《Journal of animal physiology and animal nutrition》1999,82(2-3):66-79
Introduction Carnitine (trimethyl-γ-amino-β-hydroxybutyrate; molecular weight 161 g) is not only essential for the transport and utilization of long-chain fatty acids, it also occurs as a medium and short-chain ester and serves as an acetyl and acyl pool. Short-term muscle exercise causes an increase of acetyl-carnitine levels in the serum and in the liver. It prevents the accumulation of acyl-coenzyme A (CoA) and provides the organism with CoA by producing acetyl-carnitine from acetyl-CoA. Human muscle tissue contains approximately 10 μmol CoA/kg, whereas carnitine levels range between 2000 and 5000 μmol/kg. 相似文献
687.
H Alansari R B Duncan J C Baker L N Potgieter 《Journal of veterinary diagnostic investigation》1999,11(3):215-220
Two different respiratory syncytial virus (RSV) radiolabeled probes were used to characterize the genetic heterogeneity of 25 ruminant RSV isolates by the ribonuclease protection assay. A 32P-radiolabeled antisense RNA probe was transcribed from cloned ovine and bovine RSV G glycoprotein genes and then hybridized with total RNA isolated from infected cells with various ruminant RSV isolates. The results of this study, along with previously published nucleotide sequence data of the ovine RSV G glycoprotein gene, suggest the presence of at least 2 ruminant RSV subgroups. One subgroup is represented by RSV isolated from respiratory disease outbreaks from calves and goats, and the other is represented by RSV isolated from sheep. 相似文献
688.
The use of forage brassicas, such as kale, in diets of ruminants is typically constrained by the presence of anti-metabolites that break down in the rumen to cause detrimental effects after absorption including haemolytic anaemia and tissue damage. Ensilage of kale before feeding may provide conditions that favour the degradation of potentially toxic anti-metabolites, thereby improving the nutritive value of the feed. An experiment was conducted with eighty Scottish Blackface housed lambs, in which four levels of kale silage were used to replace grass silage and in which the forage component comprised around 60% of the finishing diet. Productivity of lambs was not affected other than to increase the killing-out percentage of the lambs. Glucosinolate concentrations in kale were markedly reduced by the ensiling process. Haematological parameters, such as packed cell volume, haemoglobin concentration and the presence of Heinz−Ehrlich bodies, were not significantly affected by replacing grass silage with kale silage. Similarly, there were no significant effects arising from the dietary treatments on the blood plasma components, gamma-glutamyl transpeptidase, blood urea nitrogen, tri-iodothyroxine and thyroxine, which are conventional measures of glucosinolate toxicity.
The results indicated that the ensilage of kale reduces its toxicity and hence removes constraints on the maximum inclusion levels in the diet. Also, it was possible to reduce the potential contamination of carcasses with soil by lambs not grazing the crop and thus keeping fleeces clean. 相似文献
The results indicated that the ensilage of kale reduces its toxicity and hence removes constraints on the maximum inclusion levels in the diet. Also, it was possible to reduce the potential contamination of carcasses with soil by lambs not grazing the crop and thus keeping fleeces clean. 相似文献
689.
The commercial available diatomaceous earth Fossil Shield® and the neem product Neem Azal-T/S® are tested as single treatments and in combination as controls for the stored product pests Sitophilus oryzae (L.) and Tribolium castaneum (Herbst). The diatomaceous earth, applied in concentrations of 0.5 g, 1 g and 2 g kg-1 rice, reduced numbers of surviving beetles significantly (over a period of 3 weeks). A single treatment with the neem product, in concentrations of 0.01 g, 0.1 g, 0.2 g and 1 g azadirachtin kg-1 rice, increased the mortality rate for both species significantly. The combination of neem and diatomaceous earth (1 g diatomaceous earth with 0.2 g or 1 g azadirachtin kg-1 rice) was more effective than the single treatment in reducing numbers of surviving beetles. 相似文献
690.
J. A. M. Botermans M. S. Hedemann M. S. rhede‐Winzell CH. Erlanson‐Albertsson J. Svendsen L. Evilevitch S. G. Pierzynowski 《Journal of animal physiology and animal nutrition》2000,83(1)
The effect of night feeding and feeding frequency on exocrine pancreatic secretion was studied in five chronically catherized growing pigs (16 to 31 kg). Feeding during the night (2200 to 2400 h) as compared to the day (1000 to 1200 h) tended to stimulate cholesterol ester lipase activity and tended to lower the colipase : lipase ratio in the pancreatic juice, but no effect on volume output, protein output and the activities of trypsin, chymotrypsin, amylase, lipase and colipase could be demonstrated. Feeding 12 small meals between 0800 and 2000 h as compared to one large meal (1000 to 1200 h) daily, altered the pattern of exocrine pancreatic secretion, tended to stimulate protein output by 44 %, chymotrypsin activity by 29 % and lipase activity by 46 %. These observations strengthened the theory that exocrine pancreatic secretion is partly regulated by feed intake per se and does not only depend on the amount of feed consumed. Feeding 12 small meals versus one large meal, compared at the same total daily feed intake, lowered the colipase : lipase ratio by 32 %. It can be concluded that feed intake pattern affected exocrine pancreatic secretion. 相似文献