全文获取类型
收费全文 | 128018篇 |
免费 | 10290篇 |
国内免费 | 8620篇 |
出版年
2023年 | 1475篇 |
2022年 | 1679篇 |
2021年 | 6089篇 |
2020年 | 4139篇 |
2019年 | 5078篇 |
2018年 | 5049篇 |
2017年 | 3769篇 |
2016年 | 5313篇 |
2015年 | 7779篇 |
2014年 | 9125篇 |
2013年 | 9735篇 |
2012年 | 11733篇 |
2011年 | 10518篇 |
2010年 | 6532篇 |
2009年 | 5768篇 |
2008年 | 6736篇 |
2007年 | 6000篇 |
2006年 | 5347篇 |
2005年 | 4173篇 |
2004年 | 3696篇 |
2003年 | 3148篇 |
2002年 | 2735篇 |
2001年 | 2428篇 |
2000年 | 2255篇 |
1999年 | 2193篇 |
1998年 | 1258篇 |
1997年 | 1357篇 |
1996年 | 1195篇 |
1995年 | 1087篇 |
1994年 | 1129篇 |
1993年 | 784篇 |
1992年 | 1180篇 |
1991年 | 989篇 |
1990年 | 727篇 |
1989年 | 663篇 |
1988年 | 570篇 |
1987年 | 507篇 |
1986年 | 473篇 |
1985年 | 465篇 |
1984年 | 270篇 |
1983年 | 244篇 |
1982年 | 167篇 |
1981年 | 138篇 |
1980年 | 129篇 |
1979年 | 140篇 |
1978年 | 93篇 |
1976年 | 76篇 |
1975年 | 77篇 |
1974年 | 84篇 |
1972年 | 78篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
We isolated a recombinant H9N2 avian influenza virus (AIV) from fresh egret feces in the Ardeidae protection region of the Dongting Lake wetland area in China, and it was designated A/Egret/Hunan/1/2012(H9N2). This is the first report of isolating H9N2 AIV from wild birds in the Dongting Lake wetland. Its eight gene segments are generated by reassortment of gene segments of different AIV subtypes. These results are helpful for understanding the epidemiology and evolution of AIV in wild birds during migration. 相似文献
23.
24.
25.
26.
M N Lorenzo R Y Khan Y Wang S C Tai G C Chan A H Cheung P A Marsden 《Biochimica et biophysica acta》2001,1522(1):46-52
Generation of the functionally pleiotropic members of the endothelin vasoactive peptide family is critically catalyzed by unique type II metalloproteases, termed endothelin converting enzymes (ECE). Isolation of human ECE-2 (EC 3.4.24.71) cDNAs revealed deduced open reading frames of 787 and 765 amino acids with approximately 60% identity with human ECE-1. Characterization of mRNA variants revealed mRNA structural diversity at the 5'-terminus. Two mRNA species exist containing distinct first and second exons. Furthermore, in one of these species, an in-frame deletion of the intracytoplasmic domain removed 29 amino acids. Because of the previously reported human genetic diseases ascribed to germline mutations of member genes of the endothelin family, ECE2 was localized in human chromosomes with fluorescence in situ hybridization and radiation hybrid mapping to 3q28-q29 and SHGC-20171/D3S1571, respectively. 相似文献
27.
28.
<正>Aristolochic acids, mutational signature, and hepatocellular carcinoma Aristolochic acids (AA) are the etiologic agents of aristolochic acid nephropathy (AAN) and contribute to the global prevalence of chronic kidney disease and urothelial cancer (Grollman et al., 2007). DNA adducts formed by AA generate a unique AT transversions mutation spectrum at 相似文献
29.
Peng Wang Ronghua Luo Min Zhang Yaqing Wang Tianzhang Song Tingting Tao Zhongyu Li Lin Jin Hongyi Zheng Wenwen Chen Mengqian Zhao Yongtang Zheng Jianhua Qin 《Cell death & disease》2020,11(12)
COVID-19, caused by SARS-CoV-2, is an acute and rapidly developing pandemic, which leads to a global health crisis. SARS-CoV-2 primarily attacks human alveoli and causes severe lung infection and damage. To better understand the molecular basis of this disease, we sought to characterize the responses of alveolar epithelium and its adjacent microvascular endothelium to viral infection under a co-culture system. SARS-CoV-2 infection caused massive virus replication and dramatic organelles remodeling in alveolar epithelial cells, alone. While, viral infection affected endothelial cells in an indirect manner, which was mediated by infected alveolar epithelium. Proteomics analysis and TEM examinations showed viral infection caused global proteomic modulations and marked ultrastructural changes in both epithelial cells and endothelial cells under the co-culture system. In particular, viral infection elicited global protein changes and structural reorganizations across many sub-cellular compartments in epithelial cells. Among the affected organelles, mitochondrion seems to be a primary target organelle. Besides, according to EM and proteomic results, we identified Daurisoline, a potent autophagy inhibitor, could inhibit virus replication effectively in host cells. Collectively, our study revealed an unrecognized cross-talk between epithelium and endothelium, which contributed to alveolar–capillary injury during SARS-CoV-2 infection. These new findings will expand our understanding of COVID-19 and may also be helpful for targeted drug development.Subject terms: Mechanisms of disease, Viral infection 相似文献
30.
Following arteriolar occlusion, tissue oxygen concentration decreases and anoxic tissue eventually develops. Although anoxia
first appears in the region most distal to the capillary at the venous end, it eventually spreads throughout the entire region
of supply. In this paper the changing oxygen concentration, from the time of occlusion until the tissue is entirely anoxic,
is examined mathematically. The equations governing oxygen transport to tissue are solved by iterating a nonlinear integral
equation. This solution is valid until anoxia first appears. After anoxia develops it is necessary to solve a moving boundary
problem. This is done using the method of matched asymptotic expansions, and accurate solutions are obtained for a wide range
of physiological conditions. 相似文献