全文获取类型
收费全文 | 2089篇 |
免费 | 220篇 |
国内免费 | 300篇 |
出版年
2024年 | 5篇 |
2023年 | 58篇 |
2022年 | 71篇 |
2021年 | 158篇 |
2020年 | 113篇 |
2019年 | 125篇 |
2018年 | 122篇 |
2017年 | 75篇 |
2016年 | 105篇 |
2015年 | 148篇 |
2014年 | 174篇 |
2013年 | 158篇 |
2012年 | 198篇 |
2011年 | 194篇 |
2010年 | 96篇 |
2009年 | 92篇 |
2008年 | 107篇 |
2007年 | 66篇 |
2006年 | 72篇 |
2005年 | 63篇 |
2004年 | 53篇 |
2003年 | 49篇 |
2002年 | 60篇 |
2001年 | 21篇 |
2000年 | 26篇 |
1999年 | 24篇 |
1998年 | 17篇 |
1997年 | 17篇 |
1996年 | 21篇 |
1995年 | 9篇 |
1994年 | 18篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 10篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1950年 | 1篇 |
排序方式: 共有2609条查询结果,搜索用时 31 毫秒
1.
Bioprocess and Biosystems Engineering - To overcome the contamination in open pond, microalgal strain selection should focus on species with tolerability to extreme environments. In this study, a... 相似文献
2.
Bioprocess and Biosystems Engineering - A substantial amount of organic matter is wasted in current wastewater treatment processes. To reclaim the value of organic matter, a two-stage... 相似文献
3.
The cicada genus Nipponosemia Kato is reviewed. Four species are illustrated, photographed and described, including three known species and one new species. A key to all species of this genusis presented, and information on the biology of Nipponosemia are provided. The systematic status of the tribe Cicadatrini and biogeography of Nipponosemia are discussed. 相似文献
4.
5.
Cong Wang Liping Jiang Saiqi Wang Hongge Shi Junwei Wang Ran Wang Yongmei Li Yinhui Dou Ying Liu Guiqin Hou Yu Ke Hongmin Liu 《PloS one》2015,10(6)
Jesridonin, a small molecule obtained through the structural modification of Oridonin, has extensive antitumor activity. In this study, we evaluated both its in vitro activity in the cancer cell line EC109 and its in vivo effect on tumor xenografts in nude mice. Apoptosis induced by Jesridonin was determined using an MTT assay, Annexin-V FITC assay and Hoechest 33258 staining. Apoptosis via mitochondrial and death receptor pathways were confirmed by detecting the regulation of MDM2, p53, and Bcl-2 family members and by activation of caspase-3/-8/-9. In addition, vena caudalis injection of Jesridonin showed significant inhibition of tumor growth in the xenograft model, and Jesridonin-induced cell apoptosis in tumor tissues was determined using TUNEL. Biochemical serum analysis of alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transferase (GGT), total protein (TP) and albumin (ALB) indicated no obvious effects on liver function. Histopathological examination of the liver, kidney, lung, heart and spleen revealed no signs of JD-induced toxicity. Taken together, these results demonstrated that Jesridonin exhibits antitumor activity in human esophageal carcinomas EC109 cells both in vitro and in vivo and demonstrated no adverse effects on major organs in nude mice. These studies provide support for new drug development. 相似文献
6.
Assignment of the human CD9 gene to chromosome 12 (region P13) by use of human specific DNA probes 总被引:2,自引:0,他引:2
P. Benoit M. S. Gross P. Frachet J. Frézal G. Uzan C. Boucheix Nguyen Van Cong 《Human genetics》1991,86(3):268-272
Summary We have used human specific DNA probes and somatic hybrid cell analysis to localize the human CD 9 gene to chromosome 12 (region p13). 相似文献
7.
The present investigation provides comparative morphometrics of the final instar nymphs of three dominant cicada species, i.e., Cryptotympana atrata (Fabricius), Meimuna mongolica (Distant) and Platypleura kaempferi (Fabricius), in Guanzhong Plain, China. Particularly, characters on the antennae, legs, and apex of abdomen of both males and females of these three species were investigated and analyzed. In addition, the numbers of hind tibial spines of the final instar nymphs of 21 representatives of Cicadoidea were compared. The results provide useful characteristics for nymph identification of related species and for further taxonomic and phylogenetic analysis of Cicadoidea. 相似文献
8.
9.
10.