首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   625篇
  免费   32篇
  2023年   2篇
  2022年   6篇
  2021年   20篇
  2020年   8篇
  2019年   9篇
  2018年   10篇
  2017年   9篇
  2016年   23篇
  2015年   35篇
  2014年   31篇
  2013年   37篇
  2012年   37篇
  2011年   35篇
  2010年   25篇
  2009年   34篇
  2008年   39篇
  2007年   34篇
  2006年   31篇
  2005年   22篇
  2004年   26篇
  2003年   27篇
  2002年   28篇
  2001年   19篇
  2000年   12篇
  1999年   9篇
  1998年   8篇
  1997年   2篇
  1996年   3篇
  1995年   2篇
  1994年   3篇
  1993年   3篇
  1992年   10篇
  1991年   6篇
  1990年   2篇
  1989年   2篇
  1987年   5篇
  1984年   6篇
  1983年   4篇
  1980年   2篇
  1979年   3篇
  1978年   2篇
  1976年   3篇
  1975年   4篇
  1974年   7篇
  1973年   2篇
  1972年   3篇
  1970年   1篇
  1968年   1篇
  1967年   1篇
  1959年   1篇
排序方式: 共有657条查询结果,搜索用时 546 毫秒
151.
152.
153.
This study deals with the synthesis of benzophenone sulfonamides hybrids (131) and screening against urease enzyme in vitro. Studies showed that several synthetic compounds were found to have good urease enzyme inhibitory activity. Compounds 1 (N′-((4′-hydroxyphenyl)(phenyl)methylene)-4′′-nitrobenzenesulfonohydrazide), 2 (N′-((4′-hydroxyphenyl)(phenyl)methylene)-3′′-nitrobenzenesulfonohydrazide), 3 (N′-((4′-hydroxyphenyl)(phenyl)methylene)-4′′-methoxybenzenesulfonohydrazide), 4 (3′′,5′′-dichloro-2′′-hydroxy-N′-((4′-hydroxyphenyl)(phenyl)methylene)benzenesulfonohydrazide), 6 (2′′,4′′-dichloro-N′-((4′-hydroxyphenyl)(phenyl)methylene)benzenesulfonohydrazide), 8 (5-(dimethylamino)-N′-((4-hydroxyphenyl)(phenyl)methylene)naphthalene-1-sulfono hydrazide), 10 (2′′-chloro-N′-((4′-hydroxyphenyl)(phenyl)methylene)benzenesulfonohydrazide), 12 (N′-((4′-hydroxyphenyl)(phenyl)methylene)benzenesulfonohydrazide) have found to be potently active having an IC50 value in the range of 3.90–17.99?µM. These compounds showed superior activity than standard acetohydroxamic acid (IC50?=?29.20?±?1.01?µM). Moreover, in silico studies on most active compounds were also performed to understand the binding interaction of most active compounds with active sites of urease enzyme. Structures of all the synthetic compounds were elucidated by 1H NMR, 13C NMR, EI-MS and FAB-MS spectroscopic techniques.  相似文献   
154.
155.
156.
The Glacidorbidae, a family restricted to the Gondwanan realm (Tasmania, southeastern and southwestern Australia, and southern Argentina and Chile), previously included five genera with 20 identified species; 19 of them are Australian, with one genus and species, Gondwanorbis magallanicus (Meier-Brook & Smith, 1976 Meier-Brook, K. & Smith, B.J. (1976) Glacidorbis Iredale, 1943, a genus of freshwater prosobranchs with a Tasmanian-Southeast Australian-South Andean distribution. Archive für Molluskenkunde 106, 191198. [Google Scholar]), from South America. Here we describe two new species of Gondwanorbis: Gondwanorbis fueguensis n. sp. from the freshwater gastropods province of Southern Patagonia (Argentina) and Gondwanorbis tricarinatus n. sp. from Chile, and a new genus and species from the freshwater gastropods province of northern Patagonia (Argentina), Patagonorbis nahuelhuapensis n. sp and n. gen.

http://www./zoobank.org/urn:lsid:zoobank.org:pub:62EA0972-3AEF-4188-8E6D-F10895CE2BEF  相似文献   
157.
158.
159.
In the present study D. discoideum has been used as a model organism to understand the role of poly (ADP-ribose) polymerase (PARP) in caspase independent paraptotic cell death pathways. D. discoideum lacks caspases and Bcl-2 family proteins; nevertheless it has 9 potential genes for PARP. PARP has been known to get activated in various cell death associated diseases. In this study kinetics of cell death induced by staurosporine (STS), a bacterial alkaloid, was established to unravel the role of PARP. It was found that STS induced cell death in D. discoideum did not involve PARP activation, however it involved cathepsin D. Results indicated that an alternative mechanism may be existing in D. discoideum that lacks Bcl-2 family proteins for STS induced cell death that evades Bax involvement.  相似文献   
160.
Hyrtioreticulins A-E (1-5) were isolated from the marine sponge Hyrtios reticulatus, along with a known alkaloid, hyrtioerectine B (6). Structural elucidation on the basis of spectral data showed that 1, 2, and 5 are new tetrahydro-β-carboline alkaloids, while 3 and 4 are new azepinoindole-type alkaloids. Hyrtioreticulins A and B (1 and 2) inhibited ubiquitin-activating enzyme (E1) with IC(50) values of 0.75 and 11μg/mL, respectively, measured by their inhibitory abilities against the formation of an E1-ubiquitin intermediate. So far, only five E1 inhibitors, panapophenanthrine, himeic acid A, largazole, and hyrtioreticulins A and B (1 and 2), have been isolated from natural sources and, among them, 1 is the most potent E1 inhibitor.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号