全文获取类型
收费全文 | 11380篇 |
免费 | 863篇 |
国内免费 | 542篇 |
专业分类
12785篇 |
出版年
2024年 | 22篇 |
2023年 | 113篇 |
2022年 | 276篇 |
2021年 | 442篇 |
2020年 | 326篇 |
2019年 | 399篇 |
2018年 | 445篇 |
2017年 | 353篇 |
2016年 | 480篇 |
2015年 | 708篇 |
2014年 | 755篇 |
2013年 | 903篇 |
2012年 | 1066篇 |
2011年 | 930篇 |
2010年 | 546篇 |
2009年 | 507篇 |
2008年 | 592篇 |
2007年 | 519篇 |
2006年 | 443篇 |
2005年 | 387篇 |
2004年 | 355篇 |
2003年 | 294篇 |
2002年 | 253篇 |
2001年 | 201篇 |
2000年 | 187篇 |
1999年 | 169篇 |
1998年 | 86篇 |
1997年 | 97篇 |
1996年 | 92篇 |
1995年 | 76篇 |
1994年 | 72篇 |
1993年 | 72篇 |
1992年 | 89篇 |
1991年 | 87篇 |
1990年 | 66篇 |
1989年 | 53篇 |
1988年 | 47篇 |
1987年 | 48篇 |
1986年 | 36篇 |
1985年 | 39篇 |
1984年 | 22篇 |
1983年 | 21篇 |
1982年 | 12篇 |
1981年 | 12篇 |
1979年 | 11篇 |
1978年 | 15篇 |
1975年 | 7篇 |
1974年 | 7篇 |
1972年 | 12篇 |
1971年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
福氏痢疾菌膜成分与细菌抗原性和毒力的关系 总被引:1,自引:0,他引:1
应用免疫转移技术,用从感染福氏痢疾菌的病人获取的恢复期血清分析了福氏痢疾菌膜成分与细菌抗原性和毒力的关一。发现福氏痢疾菌的膜蛋白67kD和63kD均含有两种成分,一种和膜蛋白60kD都可能是保护性抗原,而另一种与膜蛋白78kD和35kD一样与福氏痢疾菌的毒力有关。采用微细胞同位素掺入示踪显示这些与病人恢复期血清反应的膜蛋白由质粒编码。 相似文献
103.
DNA polymerase alpha from the nuclear matrix of cells infected with simian virus 40. 总被引:7,自引:1,他引:6 下载免费PDF全文
The nuclear matrix prepared from normal, simian virus 40 (SV40)-infected, and SV40-transformed cells contained DNA polymerase activities. Approximately 12% of the total DNA polymerase activities in isolated nuclei remained with the nuclear matrix. alpha-polymerase was the major matrix DNA polymerase activity as judged by sensitivity to various inhibitors: aphidicolin, dideoxy-TTP, and N-ethylmaleimide. Approximately 2-4 fold higher DNA polymerase activity was detected in matrices obtained from lytically infected and virus-transformed cells than that found in normal cells. In lytically infected cells, 30-50% of the matrix-bound DNA polymerase activity solubilized by sonication co-sedimented with majority of the matrix T-antigen, and was co-precipitated with anti-T sera. The results suggest that alpha-polymerase and viral T-antigen may form a functional complex in the matrix. 相似文献
104.
Simian virus 40-Chinese hamster kidney cell interaction. V. Cooperative effect of 5-iodo-2''-deoxyuridine and mitomycin C in the enhancement of virus replication in infected cells. 总被引:1,自引:0,他引:1 下载免费PDF全文
A cooperative effect of 5-iodo-2'-deoxyuridine and mitomycin C which amplified (10- to 50-fold) their stimulating effect on simian virus 40 replication was obtained in infected Chinese hamster kidney cells. The results indicate that these drugs act at different levels to modify the permissiveness of cells to simian virus 40. 相似文献
105.
Fatty acids in phospholipids of cells, cysts, and germinating cysts of Azotobacter vinelandii. 下载免费PDF全文
Cyclopropane fatty acids constitute 25% of the phospholipid acyl groups in cysts of Azotobacter vinelandii. These are lost by dilution during germination when the synthesis of the fatty acids characteristic of vegetative cell phospholipids commences. 相似文献
106.
107.
108.
109.
The primary objective of this study was to construct an immune-related long noncoding RNAs (IRLs) classifier to precisely predict the prognosis and immunotherapy response of patients with thymic epithelial tumors (TET). Based on univariable Cox regression analysis and Lasso regression, six prognosis-related IRLs (AC004466.3, , AC138207.2, AC148477.2, HOXB-AS1 and SNHG8) were selected to build an IRL classifier. Importantly, results of qRT-PCR validated that higher expression levels of AL450270.1, AC138207.2, AC148477.2 and SNHG8 as well as lower expression levels of AC004466.3, and HOXB-AS1 in TETs samples compared with normal controls. The IRL classifier could effectively classify patients into the low-risk and high-risk groups based on the different survival parameters. In terms of predictive ability and clinical utility, the IRL classifier was superior to Masaoka staging system. Additionally, IRL classifier is significantly associated with immune cells infiltration (dendritic cells, activated CD4 memory T cells and tumor-infiltrating lymphocyte (TIL), T cell subsets in particular), immune microenvironment (immune score and immune checkpoint inhibitors) and immunogenicity (TMB) in TETs, which hints that IRL classifier is tightly correlated with immune characteristics and might guide more effective immunotherapy strategies for TETs patients. Encouragingly, according to TIDE algorithm, there were more immunotherapy responders in the low-risk IRL subgroup and the IRL score was robustly negatively linked to the immunotherapeutic response. To sum up, the IRL classifier was established, which can be used to predict the prognosis, immune infiltration status, immunotherapy response in TETs patients, and may facilitate personalized counseling for immunotherapy. AL450270.1相似文献