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   8481篇
  免费   254篇
  国内免费   3篇
  2023年   44篇
  2022年   55篇
  2021年   74篇
  2020年   66篇
  2019年   93篇
  2018年   69篇
  2017年   87篇
  2016年   81篇
  2015年   148篇
  2014年   292篇
  2013年   854篇
  2012年   296篇
  2011年   326篇
  2010年   352篇
  2009年   331篇
  2008年   437篇
  2007年   349篇
  2006年   327篇
  2005年   347篇
  2004年   400篇
  2003年   405篇
  2002年   378篇
  2001年   313篇
  2000年   310篇
  1999年   251篇
  1998年   164篇
  1997年   132篇
  1996年   125篇
  1995年   85篇
  1994年   113篇
  1993年   131篇
  1992年   92篇
  1991年   77篇
  1990年   79篇
  1989年   83篇
  1988年   54篇
  1987年   59篇
  1986年   51篇
  1985年   75篇
  1984年   73篇
  1983年   89篇
  1982年   79篇
  1981年   72篇
  1980年   70篇
  1979年   51篇
  1978年   53篇
  1977年   50篇
  1975年   33篇
  1974年   37篇
  1973年   35篇
排序方式: 共有8738条查询结果,搜索用时 15 毫秒
21.

Background  

A reliable extraction technique for resolving multiple spots in light or electron microscopic images is essential in investigations of the spatial distribution and dynamics of specific proteins inside cells and tissues. Currently, automatic spot extraction and characterization in complex microscopic images poses many challenges to conventional image processing methods.  相似文献   
22.
23.
24.
25.
This study considered the physiological modulation of liver proteins due to the supplementation with fish oils under two dietary backgrounds: standard or high in fat and sucrose (HFHS), and their combination with grape polyphenols. By using a quantitative proteomics approach, we showed that the capacity of the supplements for regulating proteins depended on the diet; namely, 10 different proteins changed into standard diets, while 45 changed into the HFHS diets and only scarcely proteins were found altered in common. However, in both contexts, fish oils were the main regulatory force, although the addition of polyphenols was able to modulate some fish oils' effects. Moreover, we demonstrated the ability of fish oils and their combination with grape polyphenols in improving biochemical parameters and reducing lipogenesis and glycolysis enzymes, enhancing fatty acid beta-oxidation and insulin signaling and ameliorating endoplasmic reticulum stress and protein oxidation when they are included in an unhealthy diet.  相似文献   
26.
Multidrug resistance (MDR) is a major problem in cancer chemotherapy. As P-glycoprotein is the key molecule in MDR, many investigators have constructed anti-P-glycoprotein monoclonal antibodies (MAbs). Those antibodies, including MRK16 and C219, were used for elucidation of the mechanism of MDR and for overcoming of MDR. This article describes the characterization of the antibodies against the P-glycoprotein and other proteins of multidrug-resistant tumor cells, and discusses the therapeutic implication of the antibodies.Abbreviation ADCC antibody-dependent cell-mediated cytotoxicity  相似文献   
27.
Three new isopimarane-type diterpenoids, named callicapene M1 (1), callicapene M2 (2), and callicapene M3 (3), together with four known isopimarane-type diterpenoids (4, 5, 6, 7), were isolated from the Callicarpa macrophylla Vahl. Their structures were elucidated by spectroscopic techniques (IR, UV, MS, 1D, 2D NMR). The isolated compounds 6 and 7 exhibited potent inhibitory activity with inhibition rates of 40.23–46.78% on NO production in LPS-activated RAW 264.7 macrophage cells by using MTT assays.  相似文献   
28.
29.
Thelohanellus hovorkai (Myxosporea: Myxozoa) was transmitted to common carp Cyprinus carpio by exposing fish to Aurantiactinomyxon spores collected from the oligochaete Branchiura sowerbyi. The morphological characteristics of the actinosporean stage are described in detail. B. sowerbyi were exposed to T. hovorkai spores isolated from the experimentally infected carp, and after 3 and 4 months the worms exhibited prevalences of the actinosporean stage at 19.47% (7/36) and 14.6% (6/41), respectively. Control, unexposed worms were negative for the actinosporean infection. This is the first report of an Aurantiactinomyxon transforming into a myxosporean belonging to the suborder Platysporina.  相似文献   
30.
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