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   313篇
  免费   11篇
  324篇
  2023年   2篇
  2022年   12篇
  2021年   28篇
  2020年   4篇
  2019年   12篇
  2018年   12篇
  2017年   6篇
  2016年   8篇
  2015年   23篇
  2014年   16篇
  2013年   15篇
  2012年   22篇
  2011年   28篇
  2010年   13篇
  2009年   13篇
  2008年   18篇
  2007年   11篇
  2006年   11篇
  2005年   18篇
  2004年   14篇
  2003年   17篇
  2002年   4篇
  2001年   2篇
  2000年   1篇
  1999年   1篇
  1998年   1篇
  1996年   2篇
  1995年   1篇
  1991年   3篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1974年   1篇
排序方式: 共有324条查询结果,搜索用时 0 毫秒
61.
62.
To evaluate the geographic distribution of Giardia intestinalis genotypes in Nablus, West Bank, Palestine, a genotyping study was performed using clinical fecal samples. Microscopic examination confirmed that 8 of 69 (11.6%) samples were G. intestinalis positive, and subsequent genotyping analyses targeting the small-subunit ribosomal RNA (18S rRNA) and glutamate dehydrogenase (GDH) genes revealed the G. intestinalis genotypes within the 8 samples. Of these 8 samples, 6 were clustered with assemblage A-II and the remaining 2 samples were clustered with assemblage B by 18S rRNA gene analysis; however, direct sequencing of the GDH gene segments from the latter 2 samples showed a mixed infection profile. To assess those samples, we employed a subcloning approach and successfully isolated 6 independent assemblage B subgenotypes. These partial GDH gene sequences (393 bp) had 15 single-nucleotide polymorphisms, all of which were synonymous transition substitutions at the third nucleotide position of codons. From the results, we concluded that the highly polymorphic gene loci such as GDH gene locus might provide us an opportunity to obtain a detailed molecular data even from the samples with multiple-subgenotype mixed infections. Therefore, subcloning approach is recommended in genotyping studies, especially in those conducted in giardiasis-endemic areas, where the repeated and cumulative infections could be commonly expected.  相似文献   
63.
A new class of CETP inhibitors was designed and prepared. These compounds are potent both in vitro and in vivo. The most active compound (12d) has shown an ability to raise HDL significantly in transgenic mouse PD model.  相似文献   
64.
65.
The current study aimed to explore the endophytic bacterial diversity of Avicennia marina and the potential roles of these endophytes in counteracting saline conditions in tomato plants. Molecular analysis revealed strains from Paenibacillus, Bacillus, Microbacterium, Citrobacter, Lysinibacillus, Halomonas, Virgibacillus, Exiguobacterium, and Vibrio. However, Bacillus pumilus AM11 and Exiguobacterium sp. AM25 showed significantly higher growth in saline media. In response to salinity stress, tomato plants treated with AM11 and AM25 showed significantly higher (~15–23%) biomass, photosynthetic rate and pigment accumulation compared to controls. Salinity-exposed plants had significantly reduced growth and increased (three-fold) lipid peroxidation, whilst glutathione, catalase, and peroxidase activities were significantly reduced. In contrast, AM11, AM25, and methionine improved these physiochemical attributes. The study concludes that the application of bacterial endophytes from plants growing in saline conditions can offer other plants similar stress-resistance potential. Such halophytic bacterial strains can be used to improve plant growth in saline conditions.  相似文献   
66.
67.
Marshall DM  Amjad I  Wolfe SA 《Plastic and reconstructive surgery》2003,111(1):56-64; discussion 65-6
Six cases that required soft-tissue replacement in the central midface are presented. The greatest number of flaps were used for large defects in patients with cleft palates who had undergone multiple previous operations. Several were for palatal defects attributable to cocaine abuse, and one was used for lining in a nasal reconstruction. There were no flap losses and, on the basis of these experiences, it is concluded that this is an excellent method for providing soft tissue in these difficult situations.  相似文献   
68.
69.
Inactivation of mitogen-activated protein kinases (MAPKs) by MAPK phosphatases (MKPs) is accomplished via substrate-induced activation of the latter enzymes; however, the structural basis for the underlying mechanism remains elusive. Here, we report the three-dimensional solution structure of the C-terminal phosphatase domain of the prototypical MKP PAC-1, determined when bound to phosphate. Structural and biochemical analyses reveal unique active site geometry of the enzyme important for binding to phosphorylated threonine and tyrosine of MAPK ERK2. Our study further demonstrates that the dynamic interaction between the N-terminal kinase binding domain and the C-terminal phosphatase domain of an MKP is directly coupled to MAPK-induced conformational change of the phosphatase active site, which is essential for eliciting its full enzymatic activity.  相似文献   
70.
Ice accumulation is a safety and operational threat in power lines,wind turbines,and transportations.Surfaces having both passive anti-icing and active deicing ...  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