全文获取类型
收费全文 | 1814篇 |
免费 | 127篇 |
出版年
2023年 | 13篇 |
2022年 | 17篇 |
2021年 | 41篇 |
2020年 | 28篇 |
2019年 | 41篇 |
2018年 | 47篇 |
2017年 | 31篇 |
2016年 | 56篇 |
2015年 | 71篇 |
2014年 | 84篇 |
2013年 | 128篇 |
2012年 | 131篇 |
2011年 | 115篇 |
2010年 | 74篇 |
2009年 | 76篇 |
2008年 | 90篇 |
2007年 | 89篇 |
2006年 | 94篇 |
2005年 | 82篇 |
2004年 | 66篇 |
2003年 | 72篇 |
2002年 | 58篇 |
2001年 | 47篇 |
2000年 | 44篇 |
1999年 | 29篇 |
1998年 | 7篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1992年 | 19篇 |
1991年 | 14篇 |
1990年 | 22篇 |
1989年 | 31篇 |
1988年 | 9篇 |
1987年 | 15篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1981年 | 11篇 |
1979年 | 11篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 12篇 |
1975年 | 11篇 |
1970年 | 6篇 |
1968年 | 8篇 |
1966年 | 5篇 |
排序方式: 共有1941条查询结果,搜索用时 265 毫秒
31.
32.
Arun Agrawal 《Human ecology: an interdisciplinary journal》1993,21(3):261-279
This paper describes and then analyzes the decision-making arrangements that prevail among the Raikas—nomadic shepherds from Western India. The paper suggests, using a simple analytical framework, that the existing distribution of decision-making during migration helps the Raikasto utilize available economies of scale, represent the different interest groups in their collectives, and control their decision-makers. At the same time, the ordinary shepherds in the camp are able to extract a comfortable subsistence from a complex and harsh environment by delegating much of their decision-making responsibilities to the leaders in the camp. To the extent shepherds in other parts of the world migrate over long distances and must confront similar issues of delegation of responsibilities and control over decision-makers, the analysis holds general relevance. 相似文献
33.
34.
Arpana Agrawal Sarah J. Brislin Kathleen K. Bucholz Danielle Dick Ronald P. Hart Emma C. Johnson Jacquelyn Meyers Jessica Salvatore Paul Slesinger COGA Collaborators Laura Almasy Tatiana Foroud Alison Goate Victor Hesselbrock John Kramer Samuel Kuperman Alison K. Merikangas John I. Nurnberger Jay Tischfield Howard J. Edenberg Bernice Porjesz 《Genes, Brain & Behavior》2023,22(5):e12864
35.
Enzymatic labeling of nucleic acids is a fundamental tool in molecular biology with virtually every aspect of nucleic acid
hybridization technique involving the use of labeled probes. Different methods for enzymatic labeling of DNA, RNA and oligonucleotide
probes are available today. In this review, we will describe both radioactive and nonradioactive labeling methods, yet the
choice of system for labeling the probe depends on the application under study. 相似文献
36.
37.
38.
Sublocalization of an Ataxia-Telangiectasia Gene Distal to D11S384 by Ancestral Haplotyping In Costa Rican Families 总被引:8,自引:4,他引:4 下载免费PDF全文
Nancy Uhrhammer Ethan Lange Oscar Porras Arash Naeim Xiaoguang Chen Sepideh Sheikhavandi Sujata Chiplunkar Lan Yang Sugandha Dandekar Teresa Liang Nima Patel Sharon Teraoka Nitin Udar Nidia Calvo Patrick Concannon Kenneth Lange Richard A. Gatti 《American journal of human genetics》1995,57(1):103-111
In an effort to localize a gene for ataxia-telangiectasia (A-T), we have genotyped 27 affected Costa Rican families, with 13 markers, in the chromosome 11q22-23 region. Significant linkage disequilibrium was detected for 9/13 markers between D11S1816 and D11S1391. Recombination events observed in these pedigrees places A-T between D11S1819 and D11S1960. One ancestral haplotype is common to 24/54 affected chromosomes and roughly two-thirds of the families. Inferred (ancestral) recombination events involving this common haplotype in earlier generations suggest that A-T is distal to D11S384 and proximal to D11S1960. Several other common haplotypes were identified, consistent with multiple mutations in a single gene. When considered together with all other evidence, this study further sublocalizes the major A-T locus to ≈200 kb, between markers S384 and S535. 相似文献
39.
Myelin was found to contain five major glycoproteins with molecular weights of 120000, 95000, 88000, 43000 and 38000. Light myelin contained only 5-7% of the amount of these glycoproteins in whole myelin, whereas heavy myelin and the membrane fraction contained amounts nearly identical with whole myelin. Since all the major and minor glycoproteins, with the exception of 120000-mol-wt. glycoprotein, were detected only after treating the myelin membrane with neuraminidase, N-acetylneuraminic acid is a terminal sugar residue in these glycoproteins. 相似文献
40.
The effect of DL-7-azatryptophan, an analogue of tryptophan, has been studied on the heterocyst spacing pattern and the probability of proheterocyst regression inAnabaena doliolum. 7-azatryptophan suppressed growth and induced heterocyst differentiation in nitrogen-free medium. In ammonium (1 mM), nitrite (2 mM) and nitrate (2 mM) supplemented media, it caused proheterocyst regression with a frequency of 100%, 35% and 10% respectively. The role of azatryptophan in nitrogen metabolism has been discussed in relation to ammonia-uptake study. 相似文献