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   1686篇
  免费   149篇
  国内免费   50篇
  2023年   25篇
  2022年   25篇
  2021年   80篇
  2020年   50篇
  2019年   66篇
  2018年   78篇
  2017年   62篇
  2016年   83篇
  2015年   84篇
  2014年   107篇
  2013年   122篇
  2012年   151篇
  2011年   154篇
  2010年   88篇
  2009年   65篇
  2008年   104篇
  2007年   81篇
  2006年   64篇
  2005年   60篇
  2004年   37篇
  2003年   33篇
  2002年   32篇
  2001年   20篇
  2000年   23篇
  1999年   26篇
  1998年   20篇
  1997年   9篇
  1996年   8篇
  1995年   2篇
  1994年   4篇
  1993年   11篇
  1992年   16篇
  1991年   7篇
  1990年   9篇
  1989年   5篇
  1988年   6篇
  1987年   7篇
  1986年   4篇
  1985年   6篇
  1984年   2篇
  1982年   4篇
  1981年   6篇
  1980年   3篇
  1979年   5篇
  1978年   5篇
  1977年   3篇
  1976年   6篇
  1975年   2篇
  1973年   5篇
  1971年   3篇
排序方式: 共有1885条查询结果,搜索用时 15 毫秒
1.
2.
Biophysics - Antibiotic resistance is a serious problem facing the world; it is increasing every year due to over or misuse of antibiotics that led to developing new mechanisms of drug resistance...  相似文献   
3.
Weng  Shaoting  Zhao  Yitian  Yu  Changhong  Wang  Xiaofan  Xiao  Xuehan  Han  Liqiang  Zhang  Kunpeng  Wang  Jiang  Yang  Guoyu 《Biotechnology letters》2021,43(11):2111-2129
Biotechnology Letters - An ideal rAAV gene editing system not only effectively edits genes at specific site, but also prevents the spread of the virus from occurring off-target or carcinogenic...  相似文献   
4.
5.
Malling-Merton 106 apple rootstocks inoculated with Pratylenchus penetrans, or uninoculated, were grown in a growth chamber in pots of loamy sand maintained at two moisture levels, 0 to -0.4 bar or 0 to -10 bars. Either inoculation or low soil moisture suppressed shoot growth and increased root necrosis. However, the nematode-soil moisture interaction was not significant.  相似文献   
6.
One of the family of voltage-gated calcium channels (VGCC), the N-type Ca2+ channel, is located predominantly in neurons and is associated with a variety of neuronal responses, including neurodegeneration. A precise mechanism for how the N-type Ca2+ channel plays a role in neurodegenerative disease, however, is unknown. In this study, we immunized N-type Ca2+ channel α1B-deficient (α1B−/−) mice and their wild type (WT) littermates with myelin oligodendrocyte glycoprotein 35–55 and analyzed the progression of experimental autoimmune encephalomyelitis (EAE). The neurological symptoms of EAE in the α1B−/− mice were less severe than in the WT mice. In conjunction with these results, sections of the spinal cord (SC) from α1B−/− mice revealed a reduction in both leukocytic infiltration and demyelination compared with WT mice. No differences were observed in the delayed-type hypersensitivity response, spleen cell proliferation, or cytokine production from splenocytes between the two genotypes. On the other hand, Western blot array analysis and RT-PCR revealed that a typical increase in the expression of MCP-1 in the SC showed a good correlation with the infiltration of leukocytes into the SC. Likewise, immunohistochemical analysis showed that the predominant source of MCP-1 was activated microglia. The cytokine-induced production of MCP-1 in primary cultured microglia from WT mice was significantly higher than that from α1B−/− mice and was significantly inhibited by a selective N-type Ca2+ channel antagonist, ω-conotoxin GVIA or a withdrawal of extracellular Ca2+. These results suggest that the N-type Ca2+ channel is involved in the pathogenesis of EAE at least in part by regulating MCP-1 production by microglia.  相似文献   
7.
Ancient argument     
Francois M. Mai 《CMAJ》1993,148(8):1344-1345
  相似文献   
8.
9.
10.
To assess the potential health risks associated with selected trace elements due to consumption of bivalves, a screening-level risk assessment was conducted through consideration of internationally accepted dietary guidelines and the calculation of hazard quotients. Seventeen edible bivalve species were collected from a local market in Dalian City, China. The ranges obtained for the trace elements analyzed in mg/kg dry weight were as follows: Cu (1.8–133), Zn (56–693), Mn (5.7–150), Se (0.2–3.8), Ni (0.56–7.67), Cd (0.04–10.3), Cr (0.48–2.23), Pb (0.01–1.63), Hg (0.07–0.35), and As (0.22–4.00). The estimated daily intake (EDI) of bivalves was 15.0–255.1 times lower than the RfD guidelines for all the trace elements studied. Further, the calculated hazard quotients (HQs) of the trace elements analyzed were well less than 1. Therefore, there were no potential human health risks to Dalian City consumers of marine bivalves.  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