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   148710篇
  免费   5139篇
  国内免费   921篇
  154770篇
  2022年   623篇
  2021年   1146篇
  2020年   852篇
  2019年   921篇
  2018年   12740篇
  2017年   11426篇
  2016年   9000篇
  2015年   3093篇
  2014年   2818篇
  2013年   3424篇
  2012年   7811篇
  2011年   15878篇
  2010年   13797篇
  2009年   9989篇
  2008年   11999篇
  2007年   13524篇
  2006年   2463篇
  2005年   2993篇
  2004年   3423篇
  2003年   3074篇
  2002年   2437篇
  2001年   1767篇
  2000年   1583篇
  1999年   1315篇
  1998年   601篇
  1997年   572篇
  1996年   622篇
  1995年   471篇
  1994年   481篇
  1993年   477篇
  1992年   970篇
  1991年   888篇
  1990年   790篇
  1989年   788篇
  1988年   791篇
  1987年   717篇
  1986年   656篇
  1985年   640篇
  1984年   605篇
  1983年   469篇
  1982年   343篇
  1981年   340篇
  1980年   322篇
  1979年   445篇
  1978年   365篇
  1975年   310篇
  1974年   307篇
  1973年   303篇
  1972年   463篇
  1971年   466篇
排序方式: 共有10000条查询结果,搜索用时 6 毫秒
91.
92.
93.
Systems biology is an approach to explain the behaviour of a system in relation to its individual components. Synthetic biology uses key hierarchical and modular concepts of systems biology to engineer novel biological systems. In my opinion the next step in biology is to use molecule-to-phenotype data using these approaches and integrate them in the form a periodic table. A periodic table in biology would provide chassis to classify, systematize and compare diversity of component properties vis-a-vis system behaviour. Using periodic table it could be possible to compute higher-level interactions from component properties. This paper examines the concept of building a bio-periodic table using protein fold as the fundamental unit.  相似文献   
94.
Ferruh Aşçi 《Biologia》2009,64(6):1146-1149
In this study, the structural characteristics, unique features, various organ measurements of males and females of the water mite Atractides (Atractides) turcicus sp. n. from Turkey are described. In addition, the study compares their characteristics with related species.  相似文献   
95.
I. ALBESA, P. BOGDANOV, A. ERASO, N.R. SPERANDEO AND M.M. DE BERTORELLO. 1995. The antibiotic activity of new synthetic isoxazolylnaphthoquinone imines was studied. Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922 were resistant to the four compounds studied (MIC > 128 µg ml−1), but Staphylococcus aureus ATCC 25923, ATCC 29213 and 30 clinical isolates of Staph. aureus were inhibited by 2-hydroxy- N -(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinone-4-imine (I). This compound diminished bloodstream infection of mice injected i.m. with Staph. aureus; septicaemia decayed significantly when I was applied at the beginning of the infection while when I was given 3 d after bacterial challenge, a significant protection was afforded. Bactericidal activity in serum increased during the 5 h after I was administered i.p.
The acetyl derivative of I had a high MIC but when inoculated orally in mice decreased the Staph. aureus counts in circulation. This protection occurred only when the schedule of administration started close to the bacterial challenge. Antibiotic activity in vivo may be associated with in vitro effects.  相似文献   
96.
Biosorption is becoming an important component in the integrated approach to the treatment of aqueous effluents. The economics of biomass technical applications are improved by using waste biomass instead of purposely-produced biomass. Biomass derived from an alginate extraction industry - Sargassum sp. - was examined for its ability to function as a biosorbent for metals such as cadmium, zinc and copper. For use in column applications, biomass should be immobilized. To the algae reinforcement, the biomass was embedded in polyethleneimine (PEI), followed by glutaraldehyde crosslinking. Equilibrium Zn and Cu isotherms were analysed using the immobilization ratio that showed the best Cd performance. Either Freundlich or Langmuir models can describe the passive biosorption equilibrium of cadmium, zinc and cooper. The preference for this series of metals by the biomass was found to be Cd > Zn > Cu, with maximum uptake values of 157.8, 118.5 and 77.4 mg/g dry weight biomass for Cd, Zn and Cu. respectively. The metal binding capacity by non-living biomass is an important quality for industrial use.  相似文献   
97.
98.
99.
100.
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