全文获取类型
收费全文 | 1631篇 |
免费 | 110篇 |
国内免费 | 1篇 |
专业分类
1742篇 |
出版年
2023年 | 16篇 |
2022年 | 36篇 |
2021年 | 65篇 |
2020年 | 27篇 |
2019年 | 37篇 |
2018年 | 35篇 |
2017年 | 37篇 |
2016年 | 37篇 |
2015年 | 88篇 |
2014年 | 76篇 |
2013年 | 88篇 |
2012年 | 139篇 |
2011年 | 122篇 |
2010年 | 90篇 |
2009年 | 55篇 |
2008年 | 87篇 |
2007年 | 102篇 |
2006年 | 72篇 |
2005年 | 73篇 |
2004年 | 58篇 |
2003年 | 63篇 |
2002年 | 63篇 |
2001年 | 11篇 |
2000年 | 18篇 |
1999年 | 15篇 |
1998年 | 12篇 |
1997年 | 14篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1982年 | 12篇 |
1981年 | 13篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 8篇 |
1967年 | 4篇 |
1965年 | 3篇 |
1964年 | 3篇 |
排序方式: 共有1742条查询结果,搜索用时 15 毫秒
81.
82.
83.
D.H. Isaac E.D.T. Atkins S. Stirm 《International journal of biological macromolecules》1981,3(3):165-170
Fibre type X-ray diffraction patterns have been obtained from oriented, semicrystalline films prepared from the sodium salt form of the bacterial capsular polysaccharide of Klebsiella serotype K9. The molecule has a pentasaccharide repeating sequence, with four neutral residues in the backbone and a glucoronic acid side chain. A novel feature of the molecule is the incorporation of α-l-rhamnose residues, one 1,2 linked and two 1,3 linked in the backbone. Analysis of the X-ray diffraction results indicate an extended three-fold helical conformation with an axially projected chemical repeat of 1.377 nm. Both left and right handed helices have been examined using linked atom least squares techniques to optimize the stereochemistry while simultaneously meeting the observed helical parameters. 相似文献
84.
Activation-induced cytidine deaminase targets DNA at sites of RNA polymerase II stalling by interaction with Spt5 总被引:1,自引:0,他引:1
Pavri R Gazumyan A Jankovic M Di Virgilio M Klein I Ansarah-Sobrinho C Resch W Yamane A Reina San-Martin B Barreto V Nieland TJ Root DE Casellas R Nussenzweig MC 《Cell》2010,143(1):122-133
Activation-induced cytidine deaminase (AID) initiates antibody gene diversification by creating U:G mismatches. However, AID is not specific for antibody genes; Off-target lesions can activate oncogenes or cause chromosome translocations. Despite its importance in these transactions little is known about how AID finds its targets. We performed an shRNA screen to identify factors required for class switch recombination (CSR) of antibody loci. We found that Spt5, a factor associated with stalled RNA polymerase II (Pol II) and single stranded DNA (ssDNA), is required for CSR. Spt5 interacts with AID, it facilitates association between AID and Pol II, and AID recruitment to its Ig and non-Ig targets. ChIP-seq experiments reveal that Spt5 colocalizes with AID and stalled Pol II. Further, Spt5 accumulation at sites of Pol II stalling is predictive of AID-induced mutation. We propose that AID is targeted to sites of Pol II stalling in part via its association with Spt5. 相似文献
85.
Protein kinase C purified from the brains of rats killed by decapitation contained isozymes -alpha, beta and -gamma, whereas brain from animals killed by CO2-anoxia contained only the -alpha and -beta forms. Immunoblotting experiments established that exposure to CO2 resulted in a selective loss of protein kinase C-gamma protein. 相似文献
86.
Isaac Chun-Hai Fung Yi Hao Jingxian Cai Yuchen Ying Braydon James Schaible Cynthia Mengxi Yu Zion Tsz Ho Tse King-Wa Fu 《PloS one》2015,10(5)
This study aimed to identify what information triggered social media users’ responses regarding infectious diseases. Chinese microblogs in 2012 regarding 42 infectious diseases were obtained through a keyword search in the Weiboscope database. Qualitative content analysis was performed for the posts pertinent to each keyword of the day of the year with the highest daily count. Similar posts were grouped and coded. We identified five categories of information that increased microblog traffic pertaining to infectious diseases: news of an outbreak or a case; health education / information; alternative health information / Traditional Chinese Medicine; commercial advertisement / entertainment; and social issues. News unrelated to the specified infectious diseases also led to elevated microblog traffic. Our study showcases the diverse contexts from which increased social media traffic occur. Our results will facilitate better health communication as causes underlying increased social media traffic are revealed. 相似文献
87.
FCRL5 Delineates Functionally Impaired Memory B Cells Associated with Plasmodium falciparum Exposure
88.
89.
Braden Kuo Manoj Bhasin Jolene Jacquart Matthew A. Scult Lauren Slipp Eric Isaac Kagan Riklin Veronique Lepoutre Nicole Comosa Beth-Ann Norton Allison Dassatti Jessica Rosenblum Andrea H. Thurler Brian C. Surjanhata Nicole N. Hasheminejad Leslee Kagan Ellen Slawsby Sowmya R. Rao Eric A. Macklin Gregory L. Fricchione Herbert Benson Towia A. Libermann Joshua Korzenik John W. Denninger 《PloS one》2015,10(4)
90.
Robert Chizimba Nicola Christofides Tobias Chirwa Isaac Singini Chineme Ozumba Simon Sikwese Hastings T. Banda Rhoda Banda Henry Chimbali Bagrey Ngwira Alister Munthali Peter Nyasulu 《PloS one》2015,10(4)