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   33505篇
  免费   3935篇
  国内免费   1282篇
  2023年   189篇
  2022年   404篇
  2021年   1008篇
  2020年   659篇
  2019年   798篇
  2018年   927篇
  2017年   802篇
  2016年   1027篇
  2015年   1384篇
  2014年   1661篇
  2013年   1887篇
  2012年   2162篇
  2011年   2140篇
  2010年   1291篇
  2009年   1201篇
  2008年   1394篇
  2007年   1253篇
  2006年   1224篇
  2005年   1027篇
  2004年   924篇
  2003年   822篇
  2002年   808篇
  2001年   2547篇
  2000年   2324篇
  1999年   1707篇
  1998年   582篇
  1997年   572篇
  1996年   508篇
  1995年   466篇
  1994年   393篇
  1993年   310篇
  1992年   805篇
  1991年   648篇
  1990年   555篇
  1989年   443篇
  1988年   355篇
  1987年   269篇
  1986年   210篇
  1985年   155篇
  1984年   104篇
  1983年   76篇
  1982年   52篇
  1981年   43篇
  1980年   29篇
  1979年   31篇
  1978年   27篇
  1976年   31篇
  1974年   24篇
  1973年   30篇
  1970年   24篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
51.
Detection of Infectious Astroviruses in Water   总被引:3,自引:2,他引:1       下载免费PDF全文
A method based on the infection of CaCo-2 cells and molecular hybridization with a specific cDNA probe has been developed for the detection of infectious astroviruses in environmental samples. By this procedure wild-type astroviruses have been detected in water from an area where a concurrent gastroenteritis outbreak was reported.  相似文献   
52.
53.
54.
55.
Journal of Plant Biochemistry and Biotechnology - The dried buds of Lonicera hypoglauca Miq. have antipyretic, antidotal and anti-inflammatory properties and as Flos lonicerae are widely used in...  相似文献   
56.
This study examines the role of neural inhibition in auditory spatial selectivity of inferior collicular neurons of the big brown bat, Eptesicus fuscus, using a two-tone inhibition paradigm. Two-tone inhibition decreases auditory spatial response areas but increases the slopes of directional sensitivity curves of inferior collicular neurons. Inferior collicular neurons have either directionally-selective or hemifield directional sensitivity curves. A directionally-selective curve always has a peak which is at least 50% larger than the minimum. A hemifield directional sensitivity curve rises from an ipsilateral angle by more than 50% and either reaches a plateau or declines by less than 50% over a range of contralateral angles. Two-tone inhibition does not change directionally-selective curves but changes most hemifield directional sensitivity curves into directionally-selective curves. Auditory spatial selectivity determined both with and without two-tone inhibition increases with increasing best-excitatory frequency. Sharpening of auditory spatial selectivity by two-tone inhibition is larger for neurons with smaller differences between excitatory and inhibitory best frequencies. The effect of two-tone inhibition on auditory spatial selectivity increases with increasing inhibitory tone intensity but decreases with increasing intertone interval. The implications of these findings in bat echolocation are discussed. Accepted: 18 January 2000  相似文献   
57.
RIG-1 signalling is responsible for the detection of cytoplasmic viral RNA molecules. DEXH (Asp-Glu-X-His) box polypeptide 58 (encoded by DHX58) is a negative regulator of the RIG-1 signalling pathway. In human, the DHX58 gene can be upregulated and can inhibit the RIG-1 signalling pathway during viral infection. In this study, porcine DHX58 gene expression patterns were studied. According to our results, the porcine DHX58 gene was upregulated not only by the stimulation of Poly I:C but also by the stimulation of 1ipopolysaccharides (LPS). One polymorphism (g.4919G>C), detected in the ninth intron, was significantly associated with some blood parameters including the red cell distribution width of 1-day-old pigs and white blood cell counts, lymphocyte absolute counts, and platelet distribution width of 17-day-old pigs (P < 0.05). Moreover, the individuals with the genotype GG have a significantly higher mean white blood cell count than individuals with genotype CC or GC (P < 0.05). Our study indicates that DHX58 is an important gene that is associated with the immune response in swine.  相似文献   
58.
59.
60.
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