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   7124篇
  免费   503篇
  国内免费   5篇
  2024年   8篇
  2023年   27篇
  2022年   78篇
  2021年   146篇
  2020年   110篇
  2019年   142篇
  2018年   234篇
  2017年   199篇
  2016年   303篇
  2015年   455篇
  2014年   466篇
  2013年   536篇
  2012年   680篇
  2011年   602篇
  2010年   366篇
  2009年   332篇
  2008年   469篇
  2007年   464篇
  2006年   368篇
  2005年   348篇
  2004年   312篇
  2003年   289篇
  2002年   224篇
  2001年   105篇
  2000年   87篇
  1999年   81篇
  1998年   38篇
  1997年   35篇
  1996年   16篇
  1995年   18篇
  1994年   11篇
  1993年   7篇
  1992年   9篇
  1991年   7篇
  1990年   5篇
  1989年   5篇
  1988年   4篇
  1987年   4篇
  1986年   4篇
  1985年   4篇
  1984年   4篇
  1983年   3篇
  1982年   3篇
  1980年   6篇
  1979年   3篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1971年   2篇
排序方式: 共有7632条查询结果,搜索用时 562 毫秒
51.
Molecular Biology Reports - Plant-derived phytochemicals such as flavonoids have been explored to be powerful antioxidants that protect against oxidative stress-related diseases. In the present...  相似文献   
52.
53.
Oh  Byeong Seob  Kim  Ji-Sun  Ryu  Seoung Woo  Yu  Seung Yeob  Lee  Jung-Sook  Park  Seung-Hwan  Kang  Se Won  Lee  Jiyoung  Lee  Mi-Kyung  Lee  Kang Hyun  Jung  Won Yong  Jung  Hyunjung  Hur  Tai-Young  Kim  Hyeun Bum  Kim  Jae-Kyung  Lee  Ju-Hoon  Jeong  Jae-Ho  Lee  Ju Huck 《Antonie van Leeuwenhoek》2021,114(12):2091-2099

An obligately anaerobic, Gram-stain-positive, non-motile, non-spore-forming and rod-shaped strain AGMB00832T was isolated from swine faeces. Phylogenetic analysis based on the 16S rRNA gene, together with the housekeeping genes, gyrB and rpoD, revealed that strain AGMB00832T belonged to the genus Faecalicatena and was most closely related to Faecalicatena orotica KCTC 15331T. In biochemical analysis, strain AGMB00832T was shown to be negative for catalase, oxidase and urease. Furthermore, the isolate was positive for β-glucosidase, β-glucuronidase, glutamic acid decarboxylase, proline arylamidase, acid phosphatase and naphthol-AS-BI-phosphohydrolase. The major cellular fatty acids (>?10%) of the isolate were C14:0, C16:0 and C18:1ω11t DMA. Based on the whole genome sequence analysis, the DNA G?+?C content of strain AGMB00832T was 44.2 mol%, and the genome size and numbers of rRNA and tRNA genes were 5,175,159 bp, 11 and 53, respectively. The average nucleotide identity and digital DNA–DNA hybridization values between strain AGMB00832T and related strains were ≤?77.4 and 22.5%, respectively. Furthermore, the genome analysis revealed the presence of genes for alkaline shock protein 23 and cation/proton antiporters, which may facilitate growth of strain AGMB00832T in alkaline culture condition. On the basis of polyphasic taxonomic approach, strain AGMB00832T represents a novel species within the genus Faecalicatena, for which the name Faecalicatena faecalis sp. nov. is proposed. The type strain is AGMB00832T (=?KCTC 15946T?=?NBRC 114613T).

  相似文献   
54.
55.
The mammalian target of rapamycin complex 1 (mTORC1) integrates nutrients, growth factors, stress, and energy status to regulate cell growth and metabolism. Amino acids promote mTORC1 lysosomal localization and subsequent activation. However, the subcellular location or interacting proteins of mTORC1 under amino acid‐deficient conditions is not completely understood. Here, we identify ADP‐ribosylation factor GTPase‐activating protein 1 (ArfGAP1) as a crucial regulator of mTORC1. ArfGAP1 interacts with mTORC1 in the absence of amino acids and inhibits mTORC1 lysosomal localization and activation. Mechanistically, the membrane curvature‐sensing amphipathic lipid packing sensor (ALPS) motifs that bind to vesicle membranes are crucial for ArfGAP1 to interact with and regulate mTORC1 activity. Importantly, ArfGAP1 represses cell growth through mTORC1 and is an independent prognostic factor for the overall survival of pancreatic cancer patients. Our study identifies ArfGAP1 as a critical regulator of mTORC1 that functions by preventing the lysosomal transport and activation of mTORC1, with potential for cancer therapeutics.  相似文献   
56.
Phytochromes are plant photoreceptors that perceive red and far-red light. Upon the perception of light in Arabidopsis, light-activated phytochromes enter the nucleus and act on a set of interacting proteins, modulating their activities and thereby altering the expression levels of ~10% of the organism’s entire gene complement. Phytochromeinteracting factors (PIFs) belonging to Arabidopsis basic helix-loop-helix (bHLH) subgroup 15 are key interacting proteins that play negative roles in light responses. Their activities are post-translationally countered by light-activated phytochromes, which promote the degradation of PIFs and directly or indirectly inhibit their binding to DNA. The PIFs share a high degree of similarity, but examinations of pif single and multiple mutants have indicated that they have shared and distinct functions in various developmental and physiological processes. These are believed to stem from differences in both intrinsic protein properties and their gene expression patterns. In an effort to clarify the basis of these shared and distinct functions, we compared recently published genome-wide ChIP data, developmental gene expression maps, and responses to various stimuli for the various PIFs. Based on our observations, we propose that the biological roles of PIFs stem from their shared and distinct DNA binding targets and specific gene expression patterns.  相似文献   
57.
Cdc25B is an essential regulator for meiotic resumption in mouse oocytes. However, the role of this phosphatase during the later stage of the meiotic cell cycle is not known. In this study, we investigated the role of Cdc25B during metaphase II (MII) arrest in mouse oocytes. Cdc25B was extensively phosphorylated during MII arrest with an increase in the phosphatase activity toward Cdk1. Downregulation of Cdc25B by antibody injection induced the formation of a pronucleus-like structure. Conversely, overexpression of Cdc25B inhibited Ca2+-mediated release from MII arrest. Moreover, Cdc25B was immediately dephosphorylated and hence inactivated during MII exit, suggesting that Cdk1 phosphorylation is required to exit from MII arrest. Interestingly, this inactivation occurred prior to cyclin B degradation. Taken together, our data demonstrate that MII arrest in mouse oocytes is tightly regulated not only by the proteolytic degradation of cyclin B but also by dynamic phosphorylation of Cdk1.  相似文献   
58.
59.
60.
Since 1858, when Hitchcock first recorded dinosaur tail traces from the Jurassic of Massachusetts, USA, a number of dinosaur tail traces have been reported. Although considered rare, at least 38 records of dinosaur tail traces have previously been reported in the literature. These occurrences are herein reviewed in order to understand their geographic and stratigraphic distribution, types of tail trace makers, and characteristics of dinosaur tail traces. Several terms for dinosaur tail traces have been employed and they are divided into tail impressions (TIs) for resting traces, and tail drag impressions (TDIs) for locomotion traces. Possible criteria for distinguishing, measuring and comparing TIs and TDIs are suggested. In addition, herringbone structures, one of the characteristic features of tail traces associated with ornithopod and theropod tracks, are discussed. Estimated speeds of tail trace makers are shown to be rather low. Finally, the abundance of tail traces associated with bipedal, rather than quadrupedal, dinosaurs is considered a reflection of behavior.  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