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   10568篇
  免费   996篇
  国内免费   569篇
  2024年   18篇
  2023年   245篇
  2022年   348篇
  2021年   628篇
  2020年   638篇
  2019年   780篇
  2018年   658篇
  2017年   407篇
  2016年   352篇
  2015年   567篇
  2014年   914篇
  2013年   912篇
  2012年   609篇
  2011年   713篇
  2010年   537篇
  2009年   596篇
  2008年   545篇
  2007年   522篇
  2006年   401篇
  2005年   341篇
  2004年   270篇
  2003年   190篇
  2002年   167篇
  2001年   94篇
  2000年   63篇
  1999年   58篇
  1998年   66篇
  1997年   51篇
  1996年   55篇
  1995年   44篇
  1994年   39篇
  1993年   33篇
  1992年   51篇
  1991年   33篇
  1990年   21篇
  1989年   13篇
  1988年   16篇
  1987年   19篇
  1986年   14篇
  1985年   11篇
  1984年   17篇
  1983年   16篇
  1982年   15篇
  1981年   13篇
  1980年   9篇
  1979年   3篇
  1978年   6篇
  1974年   4篇
  1971年   2篇
  1970年   2篇
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
1.
Plant somatic cells have the capability to switch their cell fates from differentiated to undifferentiated status under proper culture conditions, which is designated as totipotency. As a result, plant cells can easily regenerate new tissues or organs from a wide variety of explants. However, the mechanism by which plant cells have such remarkable regeneration ability is still largely unknown. In this study, we used a set of meristem-specific marker genes to analyze the patterns of stem cell differentiation in the processes of somatic embryogenesis as well as shoot or root organogenesis in vitro. Our studies furnish preliminary and important information on the patterns of the de novo stem cell differentiation during various types of in vitro organogenesis.  相似文献   
2.
We previously reported the identification of DP-1 isoforms (α and β), which are structurally C-terminus-deleted ones, and revealed the low-level expression of these isoforms. It is known that wild-type DP-1 is degraded by the ubiquitin-proteasome system, but few details are known about the domains concerned with the protein stability/instability for the proteolysis of these DP-1 isoforms. Here we identified the domains responsible for the stability/instability of DP-1. Especially, the DP-1 “Stabilon” domain was a C-terminal acidic motif and was quite important for DP-1 stability. Moreover, we propose that this DP-1 Stabilon may be useful for the stability of other nuclear proteins when fused to them.  相似文献   
3.
Abstract In a 2-year field survey, the phylloplane mycoflora on the haulm base of wheat was studied by the dilution plate technique. No significant colonisation was registered before the end of May. Cladosporium spp., 'white' and 'red' yeasts were found to be the most abundant fungi.  相似文献   
4.
《Developmental cell》2022,57(5):610-623.e8
  1. Download : Download high-res image (131KB)
  2. Download : Download full-size image
  相似文献   
5.
《Cell reports》2020,30(7):2065-2074.e4
  1. Download : Download high-res image (155KB)
  2. Download : Download full-size image
  相似文献   
6.
《Cell reports》2020,30(7):2055-2064.e5
  1. Download : Download high-res image (99KB)
  2. Download : Download full-size image
  相似文献   
7.
《Cell reports》2020,30(3):739-754.e4
  1. Download : Download high-res image (99KB)
  2. Download : Download full-size image
  相似文献   
8.
The heart is one of the least regenerative organs in the body, and highly vulnerable to the increasing incidence of cardiovascular diseases in an aging world population. Cell-based approaches aimed at cardiac repair have recently caused great public excitement. But clinical trials of patients’ own skeletal myoblasts or bone marrow cells for transplantation have been disappointing. Human embryonic stem cells (hESCs) form bona fide cardiomyocytes in vitro which are readily generated in mass culture and are being tested in animal models of heart damage. The early results, while encouraging, underscore that much remains to be done. This review focuses on the many challenges that remain before hESCs-mediated repair of the human heart becomes a reality.  相似文献   
9.
Human Amniotic Epithelial Cells (hAEC) isolated from term placenta are a promising source for regenerative medicine. However, it has long been debated whether the hAEC population consists of heterogeneous or homogeneous cells. In a previous study, we investigated the characteristics of hAEC isolated from four different regions of the amniotic membrane finding significant heterogeneity. The aim of this study was to evaluate the hepatic differentiation capability of hAEC isolated from these four regions. Human term placentae were collected after caesarean section and hAEC were isolated from four regions of the amniotic membrane (R1-R4, according to their relative distance from the umbilical cord) and treated in hepatic differentiation conditions for 14 days. hAEC-derived hepatocyte-like cells showed marked differences in the expression of hepatic markers: R4 showed higher levels of Albumin and Hepatocyte Nuclear Factor (HNF) 4α whereas R1 expressed higher Cytochrome P450 enzymes, both at the gene and protein level. These preliminary results suggest that hAEC isolated from R1 and R4 of the amniotic membrane are more prone to hepatic differentiation. Therefore, the use of hAEC from a specific region of the amniotic membrane should be taken into consideration as it could have an impact on the outcome of therapeutic applications.  相似文献   
10.
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