全文获取类型
收费全文 | 3410篇 |
免费 | 284篇 |
国内免费 | 216篇 |
出版年
2023年 | 45篇 |
2022年 | 104篇 |
2021年 | 176篇 |
2020年 | 142篇 |
2019年 | 130篇 |
2018年 | 147篇 |
2017年 | 90篇 |
2016年 | 152篇 |
2015年 | 206篇 |
2014年 | 226篇 |
2013年 | 250篇 |
2012年 | 253篇 |
2011年 | 226篇 |
2010年 | 135篇 |
2009年 | 118篇 |
2008年 | 135篇 |
2007年 | 138篇 |
2006年 | 119篇 |
2005年 | 108篇 |
2004年 | 87篇 |
2003年 | 73篇 |
2002年 | 70篇 |
2001年 | 62篇 |
2000年 | 68篇 |
1999年 | 65篇 |
1998年 | 39篇 |
1997年 | 31篇 |
1996年 | 19篇 |
1995年 | 31篇 |
1994年 | 26篇 |
1993年 | 12篇 |
1992年 | 25篇 |
1991年 | 28篇 |
1990年 | 31篇 |
1989年 | 27篇 |
1988年 | 33篇 |
1987年 | 21篇 |
1986年 | 24篇 |
1985年 | 25篇 |
1984年 | 16篇 |
1983年 | 18篇 |
1982年 | 11篇 |
1981年 | 10篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1978年 | 12篇 |
1976年 | 12篇 |
1975年 | 16篇 |
1971年 | 12篇 |
1970年 | 12篇 |
排序方式: 共有3910条查询结果,搜索用时 250 毫秒
131.
Wu Po-Ming Lin Chih-Hao Lee Hsueh-Te Shih Hsin-I Huang Chao-Ching Tu Yi-Fang 《Neurochemical research》2020,45(11):2712-2722
Neurochemical Research - Neonatal hypoxic–ischemic encephalopathy is the most common cause of neurological disability in infancy. Superimposed inflammation may further worsen neurological... 相似文献
132.
133.
134.
135.
Ruifeng Xu Jiyun Zhou Yulan He Quan Zou Xiaolong Wang 《Journal of biomolecular structure & dynamics》2013,31(8):1720-1730
DNA-binding proteins are crucial for various cellular processes and hence have become an important target for both basic research and drug development. With the avalanche of protein sequences generated in the postgenomic age, it is highly desired to establish an automated method for rapidly and accurately identifying DNA-binding proteins based on their sequence information alone. Owing to the fact that all biological species have developed beginning from a very limited number of ancestral species, it is important to take into account the evolutionary information in developing such a high-throughput tool. In view of this, a new predictor was proposed by incorporating the evolutionary information into the general form of pseudo amino acid composition via the top-n-gram approach. It was observed by comparing the new predictor with the existing methods via both jackknife test and independent data-set test that the new predictor outperformed its counterparts. It is anticipated that the new predictor may become a useful vehicle for identifying DNA-binding proteins. It has not escaped our notice that the novel approach to extract evolutionary information into the formulation of statistical samples can be used to identify many other protein attributes as well. 相似文献
136.
Wei Guo Dong Ren Xiuting Chen Xiang'an Tu Shuai Huang Min Wang Libing Song Xuenong Zou Xinsheng Peng 《Journal of cellular biochemistry》2013,114(7):1606-1615
The principal problem arising from prostate cancer (PCa) is its propensity to metastasize to bones, and it's crucial to understand the mechanism of tumor progression to metastasis in order to develop therapies that may reduce the morbidity and mortality of PCa patients. Although we had identified that microRNA(miR)‐145 could repress bone metastasis of PCa via regulating epithelial–mesenchymal transition (EMT) in previous study, it is still unknown how miR‐145 regulated EMT. In the present study, we constructed a luciferase reporter system and identified HEF1 as a direct target of miR‐145. More importantly, HEF1 was shown to promote migration, invasion and EMT of PC‐3 cells, a human PCa cell line originated from a bone metastatic PCa specimen. And HEF1 was also shown to partially mediate miR‐145 suppression of EMT and invasion. Furthermore, inhibition of HEF1 repressed bone invasion of PC‐3 cells in vivo. Expression of HEF1 was negatively correlated with miR‐145 in primary PCa and bone metastatic specimens, but HEF1 was higher in samples which were more likely to commit to bone metastasis or those with higher free prostate‐specific antigen (fPSA) levels and Gleason scores. Taken together, these findings indicate that HEF1 promotes EMT and bone invasion in prostate cancer by directly targeted by miR‐145, and miR‐145 suppresses EMT and invasion, at least in part, through repressing HEF1. J. Cell. Biochem. 114: 1606–1615, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
137.
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are intracellular Ca2+ channels that elevate cytoplasmic Ca2+ in response to the second messenger IP3. Here, we describe the identification and in vivo functional characterization of the planarian IP3R, the first intracellular Ca2+ channel to be defined in flatworms. A single IP3R gene in Dugesia japonica encoded a 2666 amino acid protein (Dj.IP3R) that shared well conserved structural features with vertebrate IP3R counterparts. Expression of an NH2-terminal Dj.IP3R region (amino acid residues 223–585) recovered high affinity 3H-IP3 binding (0.9 ± 0.1 nM) which was abolished by a single point mutation of an arginine residue (R495L) important for IP3 coordination. In situ hybridization revealed that Dj.IP3R mRNA was most strongly expressed in the pharynx and optical nerve system as well as the reproductive system in sexualized planarians. Consistent with this observed tissue distribution, in vivo RNAi of Dj.IP3R resulted in a decreased egg-laying behavior suggesting Dj.IP3R plays an upstream role in planarian reproductive physiology. 相似文献
138.
Guanjun Shen Xianzhu Wu Qian Wang Hua Tu Yue-xing Feng Jian-xin Zhao 《Journal of human evolution》2013
Most researchers believe that anatomically modern humans (AMH) first appeared in Africa 160-190 ka ago, and would not have reached eastern Asia until ∼50 ka ago. However, the credibility of these scenarios might have been compromised by a largely inaccurate and compressed chronological framework previously established for hominin fossils found in China. Recently there has been a growing body of evidence indicating the possible presence of AMH in eastern Asia ca. 100 ka ago or even earlier. Here we report high-precision mass spectrometric U-series dating of intercalated flowstone samples from Huanglong Cave, a recently discovered Late Pleistocene hominin site in northern Hubei Province, central China. Systematic excavations there have led to the in situ discovery of seven hominin teeth and dozens of stone and bone artifacts. The U-series dates on localized thin flowstone formations bracket the hominin specimens between 81 and 101 ka, currently the most narrow time span for all AMH beyond 45 ka in China, if the assignment of the hominin teeth to modern Homo sapiens holds. Alternatively this study provides further evidence for the early presence of an AMH morphology in China, through either independent evolution of local archaic populations or their assimilation with incoming AMH. Along with recent dating results for hominin samples from Homo erectus to AMH, a new extended and continuous timeline for Chinese hominin fossils is taking shape, which warrants a reconstruction of human evolution, especially the origins of modern humans in eastern Asia. 相似文献
139.
140.