全文获取类型
收费全文 | 5604篇 |
免费 | 471篇 |
国内免费 | 8篇 |
出版年
2024年 | 3篇 |
2023年 | 45篇 |
2022年 | 100篇 |
2021年 | 253篇 |
2020年 | 118篇 |
2019年 | 155篇 |
2018年 | 158篇 |
2017年 | 144篇 |
2016年 | 237篇 |
2015年 | 401篇 |
2014年 | 404篇 |
2013年 | 398篇 |
2012年 | 563篇 |
2011年 | 536篇 |
2010年 | 298篇 |
2009年 | 255篇 |
2008年 | 397篇 |
2007年 | 281篇 |
2006年 | 278篇 |
2005年 | 249篇 |
2004年 | 220篇 |
2003年 | 200篇 |
2002年 | 159篇 |
2001年 | 14篇 |
2000年 | 15篇 |
1999年 | 19篇 |
1998年 | 29篇 |
1997年 | 17篇 |
1996年 | 12篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 10篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1962年 | 4篇 |
排序方式: 共有6083条查询结果,搜索用时 15 毫秒
171.
172.
173.
174.
Everley PA Gartner CA Haas W Saghatelian A Elias JE Cravatt BF Zetter BR Gygi SP 《Molecular & cellular proteomics : MCP》2007,6(10):1771-1777
Activity-based protein profiling has emerged as a valuable technology for labeling, enriching, and assessing protein activities from complex mixtures. This is primarily accomplished via a two-step identification and quantification process. Here we show a highly quantitative and streamlined method, termed catch-and-release activity profiling of enzymes (CAPE), which reduces this procedure to a single step. Furthermore the CAPE approach has the ability to detect small quantitative changes that may have been missed by alternative mass spectrometry-based techniques. 相似文献
175.
Evolution, interactions, and biological networks 总被引:2,自引:0,他引:2
176.
177.
178.
Blodgett JA Thomas PM Li G Velasquez JE van der Donk WA Kelleher NL Metcalf WW 《Nature chemical biology》2007,3(8):480-485
Phosphinothricin tripeptide (PTT, phosphinothricylalanylalanine) is a natural-product antibiotic and potent herbicide that is produced by Streptomyces hygroscopicus ATCC 21705 (ref. 1) and Streptomyces viridochromogenes DSM 40736 (ref. 2). PTT has attracted widespread interest because of its commercial applications and unique phosphinic acid functional group. Despite intensive study since its discovery in 1972 (see ref. 3 for a comprehensive review), a number of steps early in the PTT biosynthetic pathway remain uncharacterized. Here we report a series of interdisciplinary experiments involving the construction of defined S. viridochromogenes mutants, chemical characterization of accumulated intermediates, and in vitro assay of selected enzymes to examine these critical steps in PTT biosynthesis. Our results indicate that early PTT biosynthesis involves a series of catalytic steps that to our knowledge has not been described so far, including a highly unusual reaction for carbon bond cleavage. In sum, we define a pathway for early PTT biosynthesis that is more complex than previously appreciated. 相似文献
179.
180.
Koen A. J. Pelsma Michiel H. in 't Zandt Huub J. M. Op den Camp Mike S. M. Jetten Joshua F. Dean Cornelia U. Welte 《Environmental microbiology》2022,24(1):82-97
Urbanised environments have been identified as hotspots of anthropogenic methane emissions. Especially urban aquatic ecosystems are increasingly recognised as important sources of methane. However, the microbiology behind these emissions remains unexplored. Here, we applied microcosm incubations and molecular analyses to investigate the methane-cycling community of the Amsterdam canal system in the Netherlands. The sediment methanogenic communities were dominated by Methanoregulaceae and Methanosaetaceae, with co-occurring methanotrophic Methanoperedenaceae and Methylomirabilaceae indicating the potential for anaerobic methane oxidation. Methane was readily produced after substrate amendment, suggesting an active but substrate-limited methanogenic community. Bacterial 16S rRNA gene amplicon sequencing of the sediment revealed a high relative abundance of Thermodesulfovibrionia. Canal wall biofilms showed the highest initial methanotrophic potential under oxic conditions compared to the sediment. During prolonged incubations the maximum methanotrophic rate increased to 8.08 mmol gDW−1 d−1 that was concomitant with an enrichment of Methylomonadaceae bacteria. Metagenomic analysis of the canal wall biofilm lead to the recovery of a single methanotroph metagenome-assembled genome. Taxonomic analysis showed that this methanotroph belongs to the genus Methyloglobulus. Our results underline the importance of previously unidentified and specialised environmental niches at the nexus of the natural and human-impacted carbon cycle. 相似文献