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   9817篇
  免费   811篇
  国内免费   27篇
电工技术   156篇
综合类   13篇
化学工业   2393篇
金属工艺   305篇
机械仪表   574篇
建筑科学   174篇
矿业工程   5篇
能源动力   349篇
轻工业   1034篇
水利工程   27篇
石油天然气   7篇
无线电   1752篇
一般工业技术   2078篇
冶金工业   620篇
原子能技术   102篇
自动化技术   1066篇
  2023年   116篇
  2022年   181篇
  2021年   309篇
  2020年   234篇
  2019年   256篇
  2018年   333篇
  2017年   335篇
  2016年   388篇
  2015年   335篇
  2014年   491篇
  2013年   645篇
  2012年   662篇
  2011年   775篇
  2010年   524篇
  2009年   559篇
  2008年   530篇
  2007年   407篇
  2006年   413篇
  2005年   320篇
  2004年   307篇
  2003年   287篇
  2002年   293篇
  2001年   212篇
  2000年   212篇
  1999年   190篇
  1998年   283篇
  1997年   204篇
  1996年   133篇
  1995年   114篇
  1994年   90篇
  1993年   81篇
  1992年   59篇
  1991年   44篇
  1990年   43篇
  1989年   37篇
  1988年   29篇
  1987年   31篇
  1986年   25篇
  1985年   30篇
  1984年   24篇
  1983年   15篇
  1982年   5篇
  1981年   5篇
  1980年   11篇
  1979年   9篇
  1978年   5篇
  1977年   13篇
  1976年   20篇
  1975年   6篇
  1974年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
International Journal of Information Security - This paper deals with a well-known problem in the area of the smudge attacks: when a user draws a pattern to unlock the pattern lock on a smartphone...  相似文献   
2.
The germline carrier of the BRCA1 pathogenic mutation has been well proven to confer an increased risk of breast and ovarian cancer. Despite BRCA1 biallelic pathogenic mutations being extremely rare, they have been reported to be embryonically lethal or to cause Fanconi anemia (FA). Here we describe a patient who was a 48-year-old female identified with biallelic pathogenic mutations of the BRCA1 gene, with no or very subtle FA-features. She was diagnosed with ovarian cancer and breast cancer at the ages of 43 and 44 and had a strong family history of breast and gynecological cancers.  相似文献   
3.
4.
5.
6.
The mammalian cell cycle is important in controlling normal cell proliferation and the development of various diseases. Cell cycle checkpoints are well regulated by both activators and inhibitors to avoid cell growth disorder and cancerogenesis. Cyclin dependent kinase 20 (CDK20) and p21Cip1/Waf1 are widely recognized as key regulators of cell cycle checkpoints controlling cell proliferation/growth and involving in developing multiple cancers. Emerging evidence demonstrates that these two cell cycle regulators also play an essential role in promoting cell survival independent of the cell cycle, particularly in those cells with a limited capability of proliferation, such as cardiomyocytes. These findings bring new insights into understanding cytoprotection in these tissues. Here, we summarize the new progress of the studies on these two molecules in regulating cell cycle/growth, and their new roles in cell survival by inhibiting various cell death mechanisms. We also outline their potential implications in cancerogenesis and protection in heart diseases. This information renews the knowledge in molecular natures and cellular functions of these regulators, leading to a better understanding of the pathogenesis of the associated diseases and the discovery of new therapeutic strategies.  相似文献   
7.
We demonstrate the structural evolution of polymorphic phases in Al2O3-inserted SrMnO3 ceramics synthesized by solid state reaction. While the 4H-hexagonal phase is predominant in pure SrMnO3 ceramics, a small amount of 6H-hexagonal polymorph is identified in addition to the primary 4H-hexagonal SrMnO3 and the secondary hexagonal SrAl2O4 phases in the as-sintered ceramics, evidenced by x-ray diffraction and subsequent Rietveld refinement analyses. The existence of the 6H-hexagonal SrMnO3 phase is corroborated using Raman spectroscopy. The chemical compositions and electronic structures of the Al2O3-inserted SrMnO3 compounds are also examined using energy dispersive spectroscopy and x-ray photoelectron spectroscopy, respectively. The first-principles calculations reveal that there is no clear difference between the total energies of 4H- and 6H-hexagonal polymorphs regardless of the presence/absence of Sr and oxygen vacancies. Possible origins are discussed with the estimation of actual strain based on the refined lattice parameter of 6H SrMnO3.  相似文献   
8.
9.
10.
Food Science and Biotechnology - To determine the physiochemical properties of the 4-α-glucanotransferase from Bifidobacterium sp., the bllj_0114 gene encoding 4-α-glucanotransferase was...  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