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   4971篇
  免费   638篇
  国内免费   746篇
  2024年   19篇
  2023年   116篇
  2022年   257篇
  2021年   340篇
  2020年   284篇
  2019年   320篇
  2018年   300篇
  2017年   204篇
  2016年   249篇
  2015年   394篇
  2014年   457篇
  2013年   413篇
  2012年   513篇
  2011年   411篇
  2010年   277篇
  2009年   204篇
  2008年   279篇
  2007年   212篇
  2006年   172篇
  2005年   125篇
  2004年   90篇
  2003年   98篇
  2002年   60篇
  2001年   59篇
  2000年   40篇
  1999年   42篇
  1998年   23篇
  1997年   23篇
  1996年   22篇
  1995年   20篇
  1994年   18篇
  1993年   11篇
  1992年   23篇
  1991年   20篇
  1990年   14篇
  1989年   18篇
  1988年   11篇
  1987年   19篇
  1986年   9篇
  1985年   17篇
  1983年   12篇
  1982年   9篇
  1980年   8篇
  1978年   10篇
  1977年   12篇
  1976年   8篇
  1974年   10篇
  1973年   10篇
  1971年   12篇
  1965年   7篇
排序方式: 共有6355条查询结果,搜索用时 203 毫秒
101.
Wang  Fubiao  Sun  Huimin  Rong  Lingling  Li  Zhaowei  An  Ting  Hu  Wenhai  Ye  Zipiao 《Plant Growth Regulation》2021,95(1):121-136
Plant Growth Regulation - To clarify the genotypic-dependent alternation in D1 protein turnover and PSII repair cycle and its relation to light intensity in senescent leaves of rice, two rice...  相似文献   
102.
103.
Lin  Xiaohui  Chen  Hongbin  Chen  Manli  Li  Ting  Lai  Yongxing  Lin  Longzai  Lin  Peiqiang  Liu  Ji  Zhang  Yixian  Chen  Ronghua  Du  Houwei  Jiang  Xinhong  Liu  Nan 《Molecular and cellular biochemistry》2021,476(5):2193-2201

Background: Transplantation of bone marrow-derived mesenchymal stem cells (BMSCs) is a potential therapy for cerebral ischemia. However, the underlying protective mechanism remains undetermined. Here, we tested the hypothesis that transplantation of BMSCs via intravenous injection can alleviate neurological functional deficits through activating PI3K/AKT signaling pathway after cerebral ischemia in rats.

Methods: A cerebral ischemic rat model was established by the 2 h middle cerebral artery occlusion (MCAO). Twenty-four hours later, BMSCs (1?×?106 in 1 ml PBS) from SD rats were injected into the tail vein. Neurological function was evaluated by modified neurological severity score (mNSS) and modified adhesive removal test before and on d1, d3, d7, d10 and d14 after MCAO. Protein expressions of AKT, GSK-3β, CRMP-2 and GAP-43 were detected by Western-bolt. NF-200 was detected by immunofluorescence.

Results: BMSCs transplantation did not only significantly improve the mNSS score and the adhesive-removal somatosensory test after MCAO, but also increase the density of NF-200 and the expression of p-AKT, pGSK-3β and GAP-43, while decrease the expression of pCRMP-2. Meanwhile, these effects can be suppressed by LY294002, a specific inhibitor of PI3K/AKT.

Conclusion: These data suggest that transplantation of BMSCs could promote axon growth and neurological deficit recovery after MCAO, which was associated with activation of PI3K/AKT /GSK-3β/CRMP-2 signaling pathway.

  相似文献   
104.
Wu  Ying  Jiang  Lisha  Zhang  Lingling  Liu  Xia  Yan  Lina  Luan  Ting  Rui  Can  Mao  Zhiyuan  Fan  Chong  Liu  Yu  Li  Ping  Zeng  Xin 《Mycopathologia》2021,186(2):177-188
Mycopathologia - Vulvovaginal candidiasis (VVC) caused by Candida spp. affects 70–75% of women at least once during their lives. We aim to elucidate the potential mechanism of VVC and...  相似文献   
105.
With the tremendous increase of publicly available single-cell RNA-sequencing (scRNA-seq) datasets, bioinformatics methods based on gene co-expression network are becoming efficient tools for analyzing scRNA-seq data, improving cell type prediction accuracy and in turn facilitating biological discovery. However, the current methods are mainly based on overall co-expression correlation and overlook co-expression that exists in only a subset of cells, thus fail to discover certain rare cell types and sensitive to batch effect. Here, we developed independent component analysis-based gene co-expression network inference (ICAnet) that decomposed scRNA-seq data into a series of independent gene expression components and inferred co-expression modules, which improved cell clustering and rare cell-type discovery. ICAnet showed efficient performance for cell clustering and batch integration using scRNA-seq datasets spanning multiple cells/tissues/donors/library types. It works stably on datasets produced by different library construction strategies and with different sequencing depths and cell numbers. We demonstrated the capability of ICAnet to discover rare cell types in multiple independent scRNA-seq datasets from different sources. Importantly, the identified modules activated in acute myeloid leukemia scRNA-seq datasets have the potential to serve as new diagnostic markers. Thus, ICAnet is a competitive tool for cell clustering and biological interpretations of single-cell RNA-seq data analysis.  相似文献   
106.
Dong  Chengya  Wen  Shaohong  Zhao  Shunying  Sun  Si  Zhao  Shangfeng  Dong  Wen  Han  Pingxin  Chen  Qingfang  Gong  Ting  Chen  Wentao  Liu  Wenqian  Liu  Xiangrong 《Neurochemical research》2021,46(4):755-769
Neurochemical Research - Cerebral ischemia leads to reactive astrogliosis and glial scar formation. Glial scarring can impede functional restoration during the recovery phase of stroke. Salidroside...  相似文献   
107.
108.
Zhang  Ting  He  Mao-Tao  Zhang  Xiao-Peng  Jing  Li  Zhang  Jian-Zhong 《Neurochemical research》2021,46(6):1359-1371
Neurochemical Research - Mitochondrial uncoupling protein 2 (UCP2) deficiency exacerbates brain damage following cerebral ischemia/reperfusion (I/R). The Nod-like receptor protein-3 (NLRP3)...  相似文献   
109.
110.
Camellia oleifera is believed to exhibit a complex intraspecific polyploidy phenomenon. Abnormal microsporogenesis can promote the formation of unreduced gametes in plants and lead to sexual polyploidy, so it is hypothesized that improper meiosis probably results in the formation of natural polyploidy in Camellia oleifera. In this study, based on the cytological observation of meiosis in pollen mother cells (PMCs), we found natural 2n pollen for the first time in Camellia oleifera, which may lead to the formation of natural polyploids by sexual polyploidization. Additionally, abnormal cytological behaviour during meiosis, including univalent chromosomes, extraequatorial chromosomes, early segregation, laggard chromosomes, chromosome stickiness, asynchronous meiosis and deviant cytokinesis (monad, dyads, triads), was observed, which could be the cause of 2n pollen formation. Moreover, we confirmed a relationship among the length–width ratio of flower buds, stylet length and microsporogenesis. This result suggested that we can immediately determine the microsporogenesis stages by phenotypic characteristics, which may be applicable to breeding advanced germplasm in Camellia oleifera.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-01002-5.  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