全文获取类型
收费全文 | 14656篇 |
免费 | 1173篇 |
国内免费 | 791篇 |
出版年
2023年 | 164篇 |
2022年 | 207篇 |
2021年 | 681篇 |
2020年 | 463篇 |
2019年 | 595篇 |
2018年 | 571篇 |
2017年 | 409篇 |
2016年 | 572篇 |
2015年 | 855篇 |
2014年 | 962篇 |
2013年 | 1081篇 |
2012年 | 1310篇 |
2011年 | 1196篇 |
2010年 | 747篇 |
2009年 | 659篇 |
2008年 | 743篇 |
2007年 | 698篇 |
2006年 | 591篇 |
2005年 | 520篇 |
2004年 | 459篇 |
2003年 | 371篇 |
2002年 | 327篇 |
2001年 | 308篇 |
2000年 | 253篇 |
1999年 | 229篇 |
1998年 | 145篇 |
1997年 | 142篇 |
1996年 | 145篇 |
1995年 | 110篇 |
1994年 | 111篇 |
1993年 | 81篇 |
1992年 | 134篇 |
1991年 | 102篇 |
1990年 | 78篇 |
1989年 | 78篇 |
1988年 | 63篇 |
1987年 | 71篇 |
1986年 | 64篇 |
1985年 | 50篇 |
1984年 | 48篇 |
1983年 | 41篇 |
1982年 | 24篇 |
1981年 | 13篇 |
1980年 | 16篇 |
1979年 | 19篇 |
1977年 | 14篇 |
1976年 | 11篇 |
1975年 | 9篇 |
1973年 | 10篇 |
1972年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
<正>Wide distribution and broad reactivity are cardinal features of pattern recognition receptors that allow rapid mobiliza-tion of large numbers of effectors to deal with pathogens.However, these features come with significant baggage as the receptors have been shown to interact with many intra-cellular components, collectively called danger-associated 相似文献
42.
A new method for hydrolyzing steroid conjugates (both sulfates and glucuronides conjugates) that is efficient, effective, and inexpensive is described. This method comprises incubation of the conjugates--after salting-out into ethyl acetate or elution from a C18 cartridge--with anhydrous methanolic hydrogen chloride (methanolysis) for 10 min. It has been successfully applied to our routine radioimmunoassay screening and GC/MS confirmation studies of steroids in prerace and postrace equine urine samples. Comparative GC/MS studies on entire (male horse) urine samples showed that methanolysis gave amounts of free steroids (estrone, estradiols, testosterone, estrenediols, nandrolone, androstanediols) at least as large as those obtained by solvolysis. Similar studies on urine samples from a gelding that had been administered nandrolone phenylpropionate showed that methanolysis gave larger amounts of free steroids (nandrolone, estranediols) than Helix pomatia enzymatic hydrolysis or solvolysis. Also, TLC studies on methanolysis of corticosteroid conjugates such as hydrocortisone 21-sulfate and hydrocortisone 21-phosphate showed that free corticosteroid was released in 5 min. 相似文献
43.
44.
45.
46.
Kainate receptors (KARs) are a class of ionotropic glutamate receptors that are expressed throughout the central nervous system. The function and subcellular localization of KARs are tightly regulated by accessory proteins. We have previously identified the single-pass transmembrane proteins, Neto1 and Neto2, to be associated with native KARs. In the hippocampus, Neto1, but not Neto2, controls the abundance and modulates the kinetics of postsynaptic KARs. Here we evaluated whether Neto2 regulates synaptic KAR levels in the cerebellum where Neto1 expression is limited to the deep cerebellar nuclei. In the cerebellum, where Neto2 is present abundantly, we found a ∼40% decrease in GluK2-KARs at the postsynaptic density (PSD) of Neto2-null mice. No change, however, was observed in total level of GluK2-KARs, thereby suggesting a critical role of Neto2 on the synaptic localization of cerebellar KARs. The presence of a putative class II PDZ binding motif on Neto2 led us to also investigate whether it interacts with PDZ domain-containing proteins previously implicated in regulating synaptic abundance of KARs. We identified a PDZ-dependent interaction between Neto2 and the scaffolding protein GRIP. Furthermore, coexpression of Neto2 significantly increased the amount of GRIP associated with GluK2, suggesting that Neto2 may promote and/or stabilize GluK2:GRIP interactions. Our results demonstrate that Neto2, like Neto1, is an important auxiliary protein for modulating the synaptic levels of KARs. Moreover, we propose that the interactions of Neto1/2 with various scaffolding proteins is a critical mechanism by which KARs are stabilized at diverse synapses. 相似文献
47.
48.
49.
Xiuling Li Songbai Yang Zhonglin Tang Kui Li Max F. Rothschild Bang Liu Bin Fan 《Animal genetics》2014,45(3):329-339
Due to the direction, intensity, duration and consistency of genetic selection, especially recent artificial selection, the production performance of domestic pigs has been greatly changed. Therefore, we reasoned that there must be footprints or selection signatures that had been left during domestication. In this study, with porcine 60K BeadChip genotyping data from both commercial Large White and local Chinese Tongcheng pigs, we calculated the extended haplotype homozygosity values of the two breeds using the long‐range haplotype method to detect selection signatures. We found 34 candidate regions, including 61 known genes, from Large White pigs and 25 regions comprising 57 known genes from Tongcheng pigs. Many selection signatures were found on SSC1, SSC4, SSC7 and SSC14 regions in both populations. According to quantitative trait loci and network pathway analyses, most of the regions and genes were linked to growth, reproduction and immune responses. In addition, the average genetic differentiation coefficient FST was 0.254, which means that there had already been a significant differentiation between the breeds. The findings from this study can contribute to further research on molecular mechanisms of pig evolution and domestication and also provide valuable references for improvement of their breeding and cultivation. 相似文献
50.