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   1683篇
  免费   97篇
  2022年   6篇
  2021年   13篇
  2020年   6篇
  2019年   9篇
  2018年   19篇
  2017年   11篇
  2016年   30篇
  2015年   49篇
  2014年   35篇
  2013年   88篇
  2012年   98篇
  2011年   96篇
  2010年   73篇
  2009年   66篇
  2008年   83篇
  2007年   91篇
  2006年   89篇
  2005年   89篇
  2004年   88篇
  2003年   82篇
  2002年   72篇
  2001年   47篇
  2000年   61篇
  1999年   45篇
  1998年   21篇
  1997年   27篇
  1996年   17篇
  1995年   13篇
  1994年   9篇
  1993年   14篇
  1992年   32篇
  1991年   21篇
  1990年   28篇
  1989年   31篇
  1988年   30篇
  1987年   19篇
  1986年   16篇
  1985年   23篇
  1984年   12篇
  1983年   15篇
  1982年   15篇
  1981年   10篇
  1980年   10篇
  1979年   18篇
  1978年   6篇
  1977年   6篇
  1976年   6篇
  1975年   7篇
  1974年   5篇
  1969年   4篇
排序方式: 共有1780条查询结果,搜索用时 421 毫秒
71.
72.
A major class of disease resistance (R) genes which encode nucleotide binding and leucine rich repeat (NB-LRR) proteins have been used in traditional breeding programs for crop protection. However, it has been difficult to functionally transfer NB-LRR-type R genes in taxonomically distinct families. Here we demonstrate that a pair of Arabidopsis (Brassicaceae) NB-LRR-type R genes, RPS4 and RRS1, properly function in two other Brassicaceae, Brassica rapa and Brassica napus, but also in two Solanaceae, Nicotiana benthamiana and tomato (Solanum lycopersicum). The solanaceous plants transformed with RPS4/RRS1 confer bacterial effector-specific immunity responses. Furthermore, RPS4 and RRS1, which confer resistance to a fungal pathogen Colletotrichum higginsianum in Brassicaceae, also protect against Colletotrichum orbiculare in cucumber (Cucurbitaceae). Importantly, RPS4/RRS1 transgenic plants show no autoimmune phenotypes, indicating that the NB-LRR proteins are tightly regulated. The successful transfer of two R genes at the family level implies that the downstream components of R genes are highly conserved. The functional interfamily transfer of R genes can be a powerful strategy for providing resistance to a broad range of pathogens.  相似文献   
73.
74.
Invasive ductal adenocarcinoma (IDA) of the pancreas manifests poor prognosis due to the early invasion and distant metastasis. In contrast, intraductal papillary mucinous adenoma or carcinoma (IPMA or IPMC) reveals better clinical outcomes. Various molecular mechanisms contribute to these differences but entire picture is still unclear. Recent researches emphasized the important role of miRNA in biological processes including cancer invasion and metastasis. We previously described that miR‐126 is down‐regulated in IDA compared with IPMA or IPMC, and miR‐126 regulates the expression of invasion related molecule disintegrin and metalloproteinase domain‐containing protein 9 (ADAM9). Assessing the difference of miRNA expression profiles of IDA, IPMA, and IPMC, we newly identified miR‐197 as an up‐regulated miRNA specifically in IDA. Expression of miR‐197 in pancreatic cancer cells resulted in the induction of epithelial–mesenchymal transition (EMT) along with the down‐regulation of p120 catenin which is a putative target of miR‐197. Direct interaction between miR‐197 and p120 catenin mRNA sequence was confirmed by 3′UTR assay, and knockdown of p120 catenin recapitulated EMT induction in pancreatic cancer cells. In situ hybridization of miR‐197 and immunohistochemistry of p120 catenin showed mutually exclusive patterns suggesting pivotal role of miR‐197 in the regulation of p120 catenin. This miR‐197/p120 catenin axis could be a novel therapeutic target. J. Cell. Physiol. 228: 1255–1263, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   
75.
76.
77.
To date, there are only few reports of immediate early genes (IEGs) available in insects. Aiming at identifying a conserved IEG in insects, we characterized an Egr homolog of the honeybee (AmEgr: Apis mellifera Egr). AmEgr was transiently induced in whole worker brains after seizure induction. In situ hybridization for AmEgr indicated that neural activity of a certain mushroom body (a higher brain center) neuron subtype, which is the same as that we previously identified using another non-coding IEG, termed kakusei, is more enhanced in forager brains. These findings suggest that Egr can be utilized as an IEG in insects.  相似文献   
78.
“Nagashima-type” palmoplantar keratosis (NPPK) is an autosomal recessive nonsyndromic diffuse palmoplantar keratosis characterized by well-demarcated diffuse hyperkeratosis with redness, expanding on to the dorsal surfaces of the palms and feet and the Achilles tendon area. Hyperkeratosis in NPPK is mild and nonprogressive, differentiating NPPK clinically from Mal de Meleda. We performed whole-exome and/or Sanger sequencing analyses of 13 unrelated NPPK individuals and identified biallelic putative loss-of-function mutations in SERPINB7, which encodes a cytoplasmic member of the serine protease inhibitor superfamily. We identified a major causative mutation of c.796C>T (p.Arg266) as a founder mutation in Japanese and Chinese populations. SERPINB7 was specifically present in the cytoplasm of the stratum granulosum and the stratum corneum (SC) of the epidermis. All of the identified mutants are predicted to cause premature termination upstream of the reactive site, which inhibits the proteases, suggesting a complete loss of the protease inhibitory activity of SERPINB7 in NPPK skin. On exposure of NPPK lesional skin to water, we observed a whitish spongy change in the SC, suggesting enhanced water permeation into the SC due to overactivation of proteases and a resultant loss of integrity of the SC structure. These findings provide an important framework for developing pathogenesis-based therapies for NPPK.  相似文献   
79.
80.
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