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   3456篇
  免费   174篇
  2024年   4篇
  2023年   27篇
  2022年   53篇
  2021年   87篇
  2020年   90篇
  2019年   104篇
  2018年   117篇
  2017年   102篇
  2016年   149篇
  2015年   226篇
  2014年   219篇
  2013年   248篇
  2012年   285篇
  2011年   260篇
  2010年   169篇
  2009年   149篇
  2008年   209篇
  2007年   179篇
  2006年   178篇
  2005年   138篇
  2004年   154篇
  2003年   113篇
  2002年   94篇
  2001年   29篇
  2000年   22篇
  1999年   24篇
  1998年   22篇
  1997年   14篇
  1996年   23篇
  1995年   12篇
  1994年   6篇
  1993年   8篇
  1992年   6篇
  1991年   4篇
  1990年   7篇
  1989年   11篇
  1988年   9篇
  1986年   8篇
  1985年   4篇
  1984年   9篇
  1983年   4篇
  1982年   6篇
  1981年   3篇
  1980年   3篇
  1979年   5篇
  1978年   6篇
  1975年   3篇
  1972年   3篇
  1966年   3篇
  1965年   6篇
排序方式: 共有3630条查询结果,搜索用时 15 毫秒
31.
Musashi comprises an evolutionarily conserved family of RNA‐binding proteins (RBP) that regulate cell fate decisions during embryonic development and play key roles in the maintenance of self‐renewal and differentiation of stem cells and adult tissues. More recently, several studies have shown that any dysregulation of MSI1 and MSI2 can lead to cellular dysfunctions promoting tissue instability and tumorigenesis. Moreover, several reports have characterized many molecular interactions between members of the Musashi family with ligands and receptors of the signaling pathways responsible for controlling normal embryonic development: Notch, Transforming Growth Factor Beta (TGF‐β), Wingless (Wnt) and Hedgehog Signaling (Hh); all of which, when altered, are strongly associated with cancer onset and progression, especially in pediatric tumors. In this context, the present review aims to compile possible cross‐talks between Musashi proteins and members of the above cited molecular pathways for which dysregulation plays important roles during carcinogenesis and may be modulated by these RBP.  相似文献   
32.
Prenatal and neonatal exposure to estrogenic compounds, such as ethinylestradiol (EE), promotes a variety of developmental disorders, including malformations and alterations in the morphology of glands, such as the prostate gland. Therefore, the aim of this study was to evaluate the morphological effects of neonatal exposure to EE on prostatic tissue and on the identification and quantification of gerbil gland macrophages in adult and senile Mongolian gerbils. The animals were exposed to EE (10 μg/kg/day) and to the vehicle, mineral oil (100 μL) (control group) during the first 10 days of postnatal life (lactation period). Adult gerbils were euthanized at 120 days and senile gerbils at 12 months of age. Our findings permitted verification of the presence of areas with proliferative foci in the prostate glandular portions in the adult and senile animals exposed to EE. There was also an increase in macrophages in the prostate tissue of adult and senile gerbils; these cell types alter the stromal microenvironment and possibly modify the interactions between the epithelium and stroma. Neonatal exposure to EE changes the pattern of prostatic development, leading to alterations in the arrangement of cells, including macrophages, and may be related to the onset of proliferative disorders in the prostate of adult gerbils and during aging.  相似文献   
33.
34.
35.
Environmental Biology of Fishes - This study evaluated how the plasma steroid hormones testosterone (T) and 17β-estradiol (E2) are related to follicular development in regenerating females of...  相似文献   
36.
Journal of Plant Growth Regulation - The rising demand for agricultural commodities in developing countries has put increasing pressure on land resources for higher yields, with associated growth...  相似文献   
37.

Salicylic acid (SA) is a plant hormone that stimulates the growth and metabolism of plants, also acting as an abiotic elicitor. This study aimed to evaluate the effect of SA on leaf production, leaf area and synthesis of secondary compounds in yarrow plants. The experiments were conducted under field conditions in two consecutive years and f-received SA foliar applications (T1-control; T2-1.0 mmol L−1 applications at 20, 60 and 100 days after planting (DAP) and T3-1.0 mmol L−1 applications at 100 DAP during 3 days). The exogenous application of SA resulted in increases in leaf area (total and specific), number of leaves and leaf mass ratio of yarrow plants, polyphenolic compounds, phenylalanine ammonia-lyase and chalcone synthase enzymes and the antioxidant activity of the plant extract. The HPLC–DAD–MS/MS analysis of phenolic compounds revealed increases in the amounts of quinic acid and rutin. The results of this research lead us to affirm that SA exerted both the hormonal effect on number of leaves and leaf area, and also acted as eliciting substance.

  相似文献   
38.
39.
40.
Hydrobiologia - Biological invasions and climate change are important drivers of biodiversity loss. In freshwater ecosystems, golden and zebra mussels are two highly aggressive invasive species...  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