全文获取类型
收费全文 | 59837篇 |
免费 | 6345篇 |
国内免费 | 10135篇 |
出版年
2024年 | 53篇 |
2023年 | 799篇 |
2022年 | 1139篇 |
2021年 | 2576篇 |
2020年 | 2196篇 |
2019年 | 2676篇 |
2018年 | 2418篇 |
2017年 | 1988篇 |
2016年 | 2570篇 |
2015年 | 3815篇 |
2014年 | 4696篇 |
2013年 | 4841篇 |
2012年 | 6035篇 |
2011年 | 5410篇 |
2010年 | 3724篇 |
2009年 | 3441篇 |
2008年 | 3984篇 |
2007年 | 3595篇 |
2006年 | 3295篇 |
2005年 | 2833篇 |
2004年 | 2452篇 |
2003年 | 2171篇 |
2002年 | 1871篇 |
2001年 | 1288篇 |
2000年 | 1144篇 |
1999年 | 963篇 |
1998年 | 594篇 |
1997年 | 499篇 |
1996年 | 434篇 |
1995年 | 384篇 |
1994年 | 351篇 |
1993年 | 240篇 |
1992年 | 282篇 |
1991年 | 234篇 |
1990年 | 183篇 |
1989年 | 183篇 |
1988年 | 133篇 |
1987年 | 123篇 |
1986年 | 114篇 |
1985年 | 105篇 |
1984年 | 47篇 |
1983年 | 72篇 |
1982年 | 55篇 |
1981年 | 48篇 |
1980年 | 21篇 |
1979年 | 37篇 |
1978年 | 23篇 |
1977年 | 20篇 |
1973年 | 19篇 |
1972年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Chungwen Wei Eugene Storozynsky A. J. McAdam Kun-Yun Yeh Brian R. Tilton Richard A. Willis Richard K. Barth R. John Looney Edith M. Lord J. G. Frelinger 《Cancer immunology, immunotherapy : CII》1996,42(6):362-368
Human prostate-specific antigen (PSA) has a highly restricted tissue distribution. Its expression is essentially limited
to the epithelial cells of the prostate gland. Moreover, it continues to be synthesized by prostate carcinoma cells. This
makes PSA an attractive candidate for use as a target antigen in the immunotherapy of prostate cancer. As a first step in
characterizing the specific immune response to PSA and its potential use as a tumor-rejection antigen, we have incorporated
PSA into a well-established mouse tumor model. Line 1, a mouse lung carcinoma, and P815, a mouse mastocytoma, have been transfected
with the cDNA for human PSA. Immunization with a PSA-expressing tumor cell line demonstrated a memory response to PSA which
protected against subsequent challenge with PSA-expressing, but not wild-type, tumors. Tumor-infiltrating lymphocytes could
be isolated from PSA-expressing tumors grown in naive hosts and were specifically cytotoxic against a syngeneic cell line
that expressed PSA. Immunization with tumor cells resulted in the generation of primary and memory cytotoxic T lymphocytes
(CTL) specific for PSA. The isolation of PSA-specific CTL clones from immunized animals further demonstrated that PSA can
serve as a target antigen for antitumor CTL. The immunogenicity studies carried out in this mouse tumor model provide a rationale
for the design of methods to elicit PSA-specific cell-mediated immunity in humans.
Received: 4 April 1996 / Accepted: 31 May 1996 相似文献
4.
Cun-Feng Zhao Ran Wei Xian-Chun Zhang 《Cladistics : the international journal of the Willi Hennig Society》2020,36(4):443-445
Here, we publish Lepisorus sect. Paragramma (Blume) C.F. Zhao, R. Wei & X.C. Zhang as a combinatio nova to replace the section name in Zhao et al. (2020), which was published as a status nova and turned out to be an invalid name, because we cited an incorrect basionym. A revised infrageneric classification of Lepisorus also is proposed. 相似文献
5.
Growth form and distribution of introduced plants in their native and non-native ranges in Eastern Asia and North America 总被引:1,自引:1,他引:0
There is a growing interest in understanding the influence of plant traits on their ability to spread in non-native regions. Many studies addressing this issue have been based on relatively small areas or restricted taxonomic groups. Here, we analyse a large data base involving 1567 plant species introduced between Eastern Asia and North America or from elsewhere to both regions. We related the extent of species distributions in each region to growth form and the distinction between upland and wetland habitats. We identified significant relationships between geographical distribution and plant traits in both native and exotic ranges as well as regional differences in the relationships. Range size was larger for herbaceous graminoids and forbs, especially annuals compared to perennials, than for woody species, and range size also was larger for plants of wetland compared to upland habitats. Distributions were more extensive in North America than in Eastern Asia, although native plants from both regions had broader distributions than non-natives, with exotics from elsewhere intermediate. Growth form and environment explained more of the variance in distribution of plants in North America than in Eastern Asia. The influence of growth form and habitat on distribution suggests that these traits might be related to tolerance of ecological conditions. In addition, the smaller extents of species in non-native compared to native areas suggest roles for dispersal limitation and adaptation to region-specific ecological conditions in determining distribution. 相似文献
6.
7.
<正>There is no experiencing without an experiencer,the self.Whether the experiencer knows it is"the self"that is experiencing is a different and tricky philosophical issue.Dating back to Ivan Pavlov’s dogs,the"experience"of animals has 相似文献
8.
Wei Lu 《Evolution; international journal of organic evolution》2020,74(8):1879-1880
What determines the rate at which species adapt to new climatic conditions? Weaver et al. found that the evolution of short larval periods promotes climatic niche evolution in salamanders in the genus Desmognathus. 相似文献
9.
Brucella cell surface protein (BCSP31) is potentially useful for diagnosing brucellosis. We aimed to establish a monoclonal antibody
(MAb) against Brucella melitensis BCSP31 and to investigate its distribution in diagnosis. Soluble recombinant BCSP31 was successfully expressed and purified.
Two MAbs (1F1 and 1E5) against B. melitensis BCSP31, effective in detecting both recombinant and cellular proteins, were obtained and characterized. The MAbs did not
react with Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Mycobacterium tuberculosis, or Bacillus aeruginosus, but strongly reacted with BCSP31 and B. melitensis by ELISA and Western blot analysis. We also tested different Brucella species and brucellosis using the prepared anti-BCSP31 MAbs. BCSP31 and anti-BCSP31 MAbs may play important roles in future
research in diagnosing brucellosis. 相似文献
10.