全文获取类型
收费全文 | 9481篇 |
免费 | 1000篇 |
国内免费 | 6篇 |
出版年
2021年 | 114篇 |
2020年 | 86篇 |
2019年 | 89篇 |
2018年 | 117篇 |
2017年 | 98篇 |
2016年 | 183篇 |
2015年 | 301篇 |
2014年 | 329篇 |
2013年 | 419篇 |
2012年 | 563篇 |
2011年 | 509篇 |
2010年 | 318篇 |
2009年 | 310篇 |
2008年 | 429篇 |
2007年 | 480篇 |
2006年 | 387篇 |
2005年 | 397篇 |
2004年 | 403篇 |
2003年 | 373篇 |
2002年 | 388篇 |
2001年 | 204篇 |
2000年 | 237篇 |
1999年 | 202篇 |
1998年 | 142篇 |
1997年 | 97篇 |
1996年 | 92篇 |
1995年 | 104篇 |
1994年 | 86篇 |
1993年 | 87篇 |
1992年 | 167篇 |
1991年 | 147篇 |
1990年 | 188篇 |
1989年 | 137篇 |
1988年 | 122篇 |
1987年 | 120篇 |
1986年 | 109篇 |
1985年 | 125篇 |
1984年 | 103篇 |
1983年 | 84篇 |
1982年 | 107篇 |
1981年 | 92篇 |
1980年 | 72篇 |
1979年 | 102篇 |
1978年 | 91篇 |
1977年 | 80篇 |
1976年 | 60篇 |
1975年 | 75篇 |
1974年 | 60篇 |
1973年 | 68篇 |
1971年 | 60篇 |
排序方式: 共有10000条查询结果,搜索用时 29 毫秒
991.
Redko F Clavin ML Weber D Ranea F Anke T Martino V 《Zeitschrift für Naturforschung. C, Journal of biosciences》2007,62(3-4):164-168
The isoflavonoids coumestrol, genistein and daidzein have been isolated and identified by bioassay-guided fractionation from the acetone extract of Erythrina crista galli young twigs infected with Phomopsis sp. These compounds showed antimicrobial activity against Bacillus brevis (MIC values 16.3, 64.8 and 137.8 microM, respectively). This is the first time that coumestrol, besides lutein and n-nonacosane, are reported in this species. 相似文献
992.
Meister J Weber D Martino V Sterner O Anke T 《Zeitschrift für Naturforschung. C, Journal of biosciences》2007,62(1-2):11-15
The medicinal plant Eupatorium arnottianum can be found in the Northeast and center of Argentina and the South of Bolivia. From plant material collected in Argentina an endophytic Phomopsis was isolated. The fungus was identified by microscopic features and analysis of its ITS sequence. Cultures yielded, besides mellein and nectriapyrone, a novel depsidone derivative for which we propose the name phomopsidone (1). The structure of 1 was determined from its spectroscopic data. 相似文献
993.
994.
Slevogt H Seybold J Tiwari KN Hocke AC Jonatat C Dietel S Hippenstiel S Singer BB Bachmann S Suttorp N Opitz B 《Cellular microbiology》2007,9(3):694-707
Moraxella catarrhalis is an important pathogen in patients with chronic obstructive lung disease (COPD). While M. catarrhalis has been categorized as an extracellular bacterium so far, the potential to invade human respiratory epithelium has not yet been explored. Our results obtained by electron and confocal microscopy demonstrated a considerable potential of M. catarrhalis to invade bronchial epithelial (BEAS-2B) cells, type II pneumocytes (A549) and primary small airway epithelial cells (SAEC). Moraxella invasion was dependent on cellular microfilament as well as on bacterial viability, and characterized by macropinocytosis leading to the formation of lamellipodia and engulfment of the invading organism into macropinosomes, thus indicating a trigger-like uptake mechanism. In addition, the cells examined expressed TLR2 as well as NOD1, a recently found cytosolic protein implicated in the intracellular recognition of bacterial cell wall components. Importantly, inhibition of TLR2 or NOD1 expression by RNAi significantly reduced the M. catarrhalis-induced IL-8 secretion. The role of TLR2 and NOD1 was further confirmed by overexpression assays in HEK293 cells. Overall, M. catarrhalis may employ lung epithelial cell invasion to colonize and to infect the respiratory tract, nonetheless, the bacteria are recognized by cell surface TLR2 and the intracellular surveillance molecule NOD1. 相似文献
995.
996.
Co-localization of CENP-C and CENP-H to discontinuous domains of CENP-A chromatin at human neocentromeres 总被引:4,自引:0,他引:4
Alonso A Fritz B Hasson D Abrusan G Cheung F Yoda K Radlwimmer B Ladurner AG Warburton PE 《Genome biology》2007,8(7):R148
Background
Mammalian centromere formation is dependent on chromatin that contains centromere protein (CENP)-A, which is the centromere-specific histone H3 variant. Human neocentromeres have acquired CENP-A chromatin epigenetically in ectopic chromosomal locations on low-copy complex DNA. Neocentromeres permit detailed investigation of centromeric chromatin organization that is not possible in the highly repetitive alpha satellite DNA present at endogenous centromeres. 相似文献997.
998.
Junctional adhesion molecules (JAMs) of the immunoglobulin superfamily are important in the control of vascular permeability and leukocyte transmigration across endothelial-cell surfaces, by engaging in homophilic, heterophilic and lateral interactions. Through their localization on the endothelial-cell surface and expression by platelets, JAMs contribute to adhesive interactions with circulating leukocytes and platelets. Antibody-blocking studies and studies using genetically modified mice have implicated these functions of JAMs in the regulation of leukocyte recruitment to sites of inflammation and ischaemia-reperfusion injury, in growth-factor-mediated angiogenesis, atherogenesis and neointima formation. The comparison of different JAM-family members and animal models, however, shows that the picture remains rather complex. This Review summarizes recent progress and future directions in understanding the role of JAMs as 'gate keepers' in inflammation and vascular pathology. 相似文献
999.
1000.
Annemarie MM Vlaar Angela EP Bouwmans Marinus JPG van Kroonenburgh Werner H Mess Selma C Tromp Piet GWM Wuisman Alfons GH Kessels Ania Winogrodzka Wim EJ Weber 《BMC neurology》2007,7(1):28