全文获取类型
收费全文 | 9308篇 |
免费 | 1125篇 |
国内免费 | 5篇 |
出版年
2021年 | 141篇 |
2020年 | 68篇 |
2019年 | 100篇 |
2018年 | 96篇 |
2017年 | 98篇 |
2016年 | 209篇 |
2015年 | 370篇 |
2014年 | 380篇 |
2013年 | 431篇 |
2012年 | 607篇 |
2011年 | 613篇 |
2010年 | 344篇 |
2009年 | 329篇 |
2008年 | 514篇 |
2007年 | 542篇 |
2006年 | 490篇 |
2005年 | 543篇 |
2004年 | 489篇 |
2003年 | 497篇 |
2002年 | 464篇 |
2001年 | 164篇 |
2000年 | 127篇 |
1999年 | 166篇 |
1998年 | 143篇 |
1997年 | 106篇 |
1996年 | 114篇 |
1995年 | 98篇 |
1994年 | 106篇 |
1993年 | 125篇 |
1992年 | 114篇 |
1991年 | 117篇 |
1990年 | 139篇 |
1989年 | 120篇 |
1988年 | 113篇 |
1987年 | 119篇 |
1986年 | 88篇 |
1985年 | 92篇 |
1984年 | 94篇 |
1983年 | 88篇 |
1982年 | 107篇 |
1981年 | 69篇 |
1980年 | 71篇 |
1979年 | 72篇 |
1978年 | 68篇 |
1977年 | 75篇 |
1976年 | 49篇 |
1975年 | 42篇 |
1974年 | 38篇 |
1973年 | 32篇 |
1971年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
1.
Patrick Sullivan 《CMAJ》1996,154(12):1889-1890
2.
The Species Survival Commission (SSC) of IUCN—the World Conservation Union is the largest, most comprehensive and diverse professional conservation network in existence today. It brings together over 6000 volunteers from more than 160 countries to contribute to the conservation of biological diversity by developing and executing programmes to study, save, restore, and manage wisely species and their habitats. The SSC is organized primarily along taxonomic lines, with members distributed in 96 Specialist Groups focusing on distinct groups of species. These groups are a source of the most current and expert information on the conservation status and priorities for action for species in the wild. As such, they provide an invaluable resource in setting priorities for captive propagation and in linking ex situ actions. In addition, the SSC has five disciplinary Specialist Groups that provide expertise to both the zoo community and field conservationists in areas such as reintroductions, veterinary medicine, captive breeding as a conservation tool, and the impact of invasive species on native flora and fauna. The effectiveness of the SSC is greatly enhanced by the close connections within its network between zoo professionals, academic scientists, field conservationists, and managers of natural resources. Challenges to the SSC currently include better information management, organization at the national level, and extending coverage in areas such as marine biodiversity. 相似文献
3.
Interleukin-1βconverting enzyme: A novel cysteine protease required for IL-1β production and implicated in programmed cell death 下载免费PDF全文
Nancy A. Thornberry Susan M. Molineaux 《Protein science : a publication of the Protein Society》1995,4(1):3-12
Interleukin-1β converting enzyme is the first member of a new class of cysteine proteases. The most distinguishing feature of this family is a nearly absolute specificity for cleavage at aspartic acid. This enzyme has been the subject of intense research because of its role in the production of IL-1β, a key mediator of inflammation. These studies have culminated in the design of potent inhibitors and determination of its crystal structure. The structure secures the relationship of the enzyme to CED-3, the product of a gene required for programmed cell death in Caenorhabditis elegans, suggesting that members of this family function in cell death in vertebrates. 相似文献
4.
5.
6.
Paul C. Marker Jennifer A. King Neal G. Copeland Nancy A. Jenkins David M. Kingsley 《Genomics》1995,28(3)
Murine Bmp7 has been assigned to distal Chromosome 2 by interspecific backcross mapping. The map location suggests close linkage to classical mouse mutations and places Bmp7 within a chromosome region thought to contain one or more unidentified imprinted genes. A direct test suggests that Bmp7 is not imprinted. An examination of embryonic RNA expression patterns shows that Bmp7 is expressed in a variety of skeletal and nonskeletal tissues. Both embryonic expression patterns and the human chromosomal sublocalization inferred from its mouse location make Bmp7 a candidate for the gene affected in some patients with Holt-Oram syndrome. 相似文献
7.
8.
9.
10.