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《Saudi Journal of Biological Sciences》2017,24(8):1798-1802
ObjectiveTo study the protective effect of total flavonoid in rabdosia rubescens on BIT model by brain ischemic tolerance (hereinafter BIT) model of mice.MethodBIT model is used to block bilateral common carotid arteries and to copy BIT model of mice. After 10 min of transient ischemia for rats in preconditioning group, the mice in the nimodipine group and naoluotong capsule group were given the total flavonoid in rabdosia rubescens (300 mg/kg, 150 mg/kg, 75 mg/kg) for gavage, sham operation group, ischemia/reperfusion injury (hereinafter IRI) group and BIT group were fed with the same volume of 0.5% sodium carboxymethyl cellulose (CMC) once a day for 5 days. After administration for 1 h on day 5 (120 h), the rats in the other groups except for the sham operation group were treated with blood flow block for 30 min and reperfusion for 22 h. The serum NSE level were measured and the brain NO content and NOS activity changes was measured to observe the histopathological changes of brain tissue.ResultsBIT models of mice and in rats were both successfully replicated. The total flavonoid in rabdosia rubescens can decrease the mortality of mice, decrease serum NSE level, increase the content of NO and the activity of NOS in the brain tissue of mice, and improve the pathological damage of cortex and hippocampus of mice.ConclusionThe total flavonoid in rabdosia rubescens can stimulate an endogenous protective mechanism by inducing the release of low levels of cytokines NO and NOS, which reduces the release of serum NSE, relieves the brain tissue ischemia-reperfusion injury, and further improves the protection effect of ischemic preconditioning on brain injury. The damage of brain tissue ischemia and reperfusion, and further improve the ischemia Protective effect of preconditioning on brain injury. 相似文献
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The European Common Agricultural Policy still follows its primary goals, i.e. quality food at affordable prices and a decent standard of living for farmers, fifty years after its adoption. Moreover, this policy adapts to the changing needs of society and the new challenges, mostly preservation of the environment, nature and biodiversity in rural areas. Although the Common Agricultural Policy receives the largest share of European budget, the funds are decreasing over time, especially direct payments, which aim to provide basic income support to farmers in the European Union. On the other hand, agri-environmental payments are gaining importance. Policy decision-makers should be interested in the question of impacts of growing eco-conditionality of agricultural spending. New insights would help them to be successful in achieving the goals of sustainable agriculture. The purpose of this paper is to estimate the impacts of production support payments and rural development payments on the quality of groundwater. We use the small EU country Slovenia as an example. The baseline indicators are the level of nitrates and pesticides in groundwater, while the impacts were estimated using spatial error model. The results show that direct payments, coupled subsidies and investment grants raise the level of pesticides in groundwater, but do not have any statistically significant impact on the level of nitrates in groundwater. Furthermore, we did not find any statistically significant effects of agri-environmental payments on decrease of groundwater pollution with nitrates. However, our findings revealed that agri-environmental payments are effective in reducing pesticides in groundwater, although only to a limited extent. These results imply a problem of insufficient targeting of agri-environmental measures on the one hand, and suggest that greening of direct payments is necessary and entirely justified. 相似文献
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目的:研究白芷中有效成分欧前胡素、异欧前胡素和花椒毒酚在大鼠小肠各段的吸收特征。方法:采用大鼠在体单向肠灌流模型结合HPLC法同时测定肠灌流液中欧前胡素、异欧前胡素和花椒毒酚含量的变化,考察高、中、低三组剂量下三种成分在十二指肠、空肠和回肠的吸收特性。结果:三种成分随着剂量的增大,吸收速率常数(Ka)和有效渗透系数(Peff)逐渐增大。三种成分相同剂量下各肠段间吸收均无显著性差异,其吸收大小顺序为:欧前胡素异欧前胡素花椒毒酚。结论:白芷三种主要成分在各肠段均吸收良好,吸收大小呈剂量相关性。 相似文献
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Previous researches mainly focused on the runoff responses to landuse change based on annual, seasonal or monthly time scales, there are few studies based on daily scale. We conducted a comprehensive investigation into runoff responses on the daily scale as well as annual and monthly time scales using SWAT, and compared the impacts of time scales with different time indicators quantitatively. Jinjiang, a coastal catchment of southeast China with a humid sub-tropical climate, was used for simulations. A calibrated SWAT model produced satisfactory reproduction of annual, monthly and daily runoff processes over a nine-year (2002–2010) period at three gauging stations. Runoff was then simulated and compared using the same meteorological input but two different landuse scenarios (1985 and 2006, with reduced forest and increased cropland and urbanized area). The results showed varying change in runoff among three time scales and three catchments. The annual runoff had the smallest increase between two scenarios, monthly runoffs had medium rates (increasing in all months except October–November), and daily runoff had the largest rates with the increase in flood peaks but decrease in drought flows, because of the variable influence on interception/evapotranspiration loss, percolation and antecedent soil water storage. Indicators of different time scales (annual runoff, monthly runoff, maximum 1-day and 5-day flood runoff, minimum 1-day and 7-day runoff) proved appropriate for analysing landuse change impacts. 相似文献
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We propose a variant of the discrete Lotka–Volterra model for predator–prey interactions. A detailed stability and numerical analysis of the model are presented to explore the long time behaviour as each of the control parameter is varied independently. We show how the condition for survival of the predator depends on the natural death rate of predator and the efficiency of predation. The model is found to support different dynamical regimes asymptotically including predator extinction, stable fixed point and limit cycle attractors for co-existence of predator and prey and more complex dynamics involving chaotic attractors. We are able to locate exactly the domain of chaos in the parameter plane using a dimensional analysis. 相似文献
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Structural insights into human microsomal epoxide hydrolase by combined homology modeling,molecular dynamics simulations,and molecular docking calculations 下载免费PDF全文
Patricia Saenz‐Méndez Aline Katz María Lucía Pérez‐Kempner Oscar N. Ventura Marta Vázquez 《Proteins》2017,85(4):720-730
A new homology model of human microsomal epoxide hydrolase was derived based on multiple templates. The model obtained was fully evaluated, including MD simulations and ensemble‐based docking, showing that the quality of the structure is better than that of only previously known model. Particularly, a catalytic triad was clearly identified, in agreement with the experimental information available. Analysis of intermediates in the enzymatic mechanism led to the identification of key residues for substrate binding, stereoselectivity, and intermediate stabilization during the reaction. In particular, we have confirmed the role of the oxyanion hole and the conserved motif (HGXP) in epoxide hydrolases, in excellent agreement with known experimental and computational data on similar systems. The model obtained is the first one that fully agrees with all the experimental observations on the system. Proteins 2017; 85:720–730. © 2016 Wiley Periodicals, Inc. 相似文献