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   29410篇
  免费   2353篇
  国内免费   12篇
  2023年   160篇
  2022年   123篇
  2021年   717篇
  2020年   482篇
  2019年   649篇
  2018年   770篇
  2017年   675篇
  2016年   1114篇
  2015年   1669篇
  2014年   1793篇
  2013年   2209篇
  2012年   2549篇
  2011年   2433篇
  2010年   1611篇
  2009年   1388篇
  2008年   1806篇
  2007年   1680篇
  2006年   1521篇
  2005年   1462篇
  2004年   1335篇
  2003年   1267篇
  2002年   1062篇
  2001年   190篇
  2000年   156篇
  1999年   222篇
  1998年   198篇
  1997年   177篇
  1996年   156篇
  1995年   142篇
  1994年   137篇
  1993年   136篇
  1992年   109篇
  1991年   93篇
  1990年   107篇
  1989年   89篇
  1988年   93篇
  1987年   74篇
  1986年   83篇
  1985年   77篇
  1984年   79篇
  1983年   75篇
  1982年   78篇
  1981年   77篇
  1980年   63篇
  1979年   62篇
  1978年   59篇
  1977年   50篇
  1976年   54篇
  1975年   49篇
  1973年   36篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
A formalin-fixed paraffin-embedded (FFPE) sample usually yields highly degraded DNA, which limits the use of techniques requiring high-quality DNA, such as Infinium Methylation microarrays. To overcome this restriction, we have applied an FFPE restoration procedure consisting of DNA repair and ligation processes in a set of paired fresh-frozen (FF) and FFPE samples. We validated the FFPE results in comparison with matched FF samples, enabling us to use FFPE samples on the Infinium HumanMethylation450 Methylation array.  相似文献   
2.
3.
4.
5.
6.
Toxoplasma gondii is a human protozoan parasite that belongs to the phylum of Apicomplexa and causes toxoplasmosis. As the other members of this phylum, T. gondii obligatory multiplies within a host cell by a peculiar type of mitosis that leads to daughter cell assembly within a mother cell. Although parasite growth and virulence have been linked for years, few molecules controlling mitosis have been yet identified and they include a couple of kinases but not the counteracting phosphatases. Here, we report that in contrast to other animal cells, type 2C is by far the major type of serine threonine phosphatase activity both in extracellular and in intracellular dividing parasites. Using wild type and transgenic parasites, we characterized the 37 kDa TgPP2C molecule as an abundant cytoplasmic and nuclear enzyme with activity being under tight regulation. In addition, we showed that the increase in TgPP2C activity significantly affected parasite growth by impairing cytokinesis while nuclear division still occurred. This study supports for the first time that type 2C protein phosphatase is an important regulator of cell growth in T. gondii.  相似文献   
7.
8.
9.
10.
The Na‐ion battery is recognized as a possible alternative to the Li‐ion battery for applications where power and cost override energy density performance. However, the increasing instability of their electrolyte with temperature is still problematic. Thus, a central question remains how to design Na‐based electrolytes. Here, the discovery of a Na‐based electrolyte formulation is reported which enlists four additives (vinylene carbonate, succinonitrile, 1,3‐propane sultone, and sodium difluoro(oxalate)borate) in proper quantities that synergistically combine their positive attributes to enable a stable solid electrolyte interphase at both negative and positive electrodes surface at 55 °C. Moreover, the role of each additive that consists in producing specific NaF coatings, thin elastomers, sulfate‐based deposits, and so on via combined impedance and X‐ray photoelectron spectroscopy is rationalized. It is demonstrated that empirical electrolyte design rules previously established for Li‐ion technology together with theoretical guidance is vital in the quest for better Na‐based electrolytes that can be extended to other chemistries. Overall, this finding, which is implemented to 18 650 cells, widens the route to the rapid development of the Na‐ion technology based on Na3V2(PO4)2F3/C chemistry.  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