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   6407篇
  免费   444篇
  国内免费   8篇
电工技术   92篇
综合类   5篇
化学工业   1721篇
金属工艺   147篇
机械仪表   251篇
建筑科学   214篇
矿业工程   9篇
能源动力   201篇
轻工业   1196篇
水利工程   43篇
石油天然气   40篇
无线电   413篇
一般工业技术   1117篇
冶金工业   653篇
原子能技术   31篇
自动化技术   726篇
  2024年   19篇
  2023年   74篇
  2022年   229篇
  2021年   277篇
  2020年   178篇
  2019年   217篇
  2018年   236篇
  2017年   246篇
  2016年   286篇
  2015年   183篇
  2014年   289篇
  2013年   446篇
  2012年   403篇
  2011年   433篇
  2010年   310篇
  2009年   350篇
  2008年   286篇
  2007年   268篇
  2006年   221篇
  2005年   275篇
  2004年   240篇
  2003年   187篇
  2002年   109篇
  2001年   79篇
  2000年   65篇
  1999年   70篇
  1998年   206篇
  1997年   136篇
  1996年   103篇
  1995年   58篇
  1994年   49篇
  1993年   62篇
  1992年   30篇
  1991年   25篇
  1990年   24篇
  1989年   17篇
  1988年   32篇
  1987年   15篇
  1986年   17篇
  1985年   15篇
  1984年   11篇
  1983年   7篇
  1982年   5篇
  1981年   7篇
  1980年   6篇
  1979年   8篇
  1977年   7篇
  1976年   20篇
  1974年   6篇
  1972年   4篇
排序方式: 共有6859条查询结果,搜索用时 15 毫秒
1.
2.
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   
3.
Studies related to biomaterials that stimulate the repair of living tissue have increased considerably, improving the quality of many people's lives that require surgery due to traumatic accidents, bone diseases, bone defects, and reconstructions. Among these biomaterials, bioceramics and bioactive glasses (BGs) have proved to be suitable for coating materials, cement, scaffolds, and nanoparticles, once they present good biocompatibility and degradability, able to generate osteoconduction on the surrounding tissue. However, the role of biomaterials in hard tissue engineering is not restricted to a structural replacement or for guiding tissue regeneration. Nowadays, it is expected that biomaterials develop a multifunctional role when implanted, orchestrating the process of tissue regeneration and providing to the body the capacity to heal itself. In this way, the incorporation of specific metal ions in bioceramics and BGs structure, including magnesium, silver, strontium, lithium, copper, iron, zinc, cobalt, and manganese are currently receiving enhanced interest as biomaterials for biomedical applications. When an ion is incorporated into the bioceramic structure, a new category of material is created, which has several unique properties that overcome the disadvantages of primitive material and favors its use in different biomedical applications. The doping can enhance handling properties, angiogenic and osteogenic performance, and antimicrobial activity. Therefore, this review aims to summarize the effect of selected metal ion dopants into bioceramics and silicate-based BGs in bone tissue engineering. Furthermore, new applications for doped bioceramics and BGs are highlighted, including cancer treatment and drug delivery.  相似文献   
4.
5.
Angiotensin converting enzyme 2 (ACE2) is the human receptor that interacts with the spike protein of coronaviruses, including the one that produced the 2020 coronavirus pandemic (COVID-19). Thus, ACE2 is a potential target for drugs that disrupt the interaction of human cells with SARS-CoV-2 to abolish infection. There is also interest in drugs that inhibit or activate ACE2, that is, for cardiovascular disorders or colitis. Compounds binding at alternative sites could allosterically affect the interaction with the spike protein. Herein, we review biochemical, chemical biology, and structural information on ACE2, including the recent cryoEM structures of full-length ACE2. We conclude that ACE2 is very dynamic and that allosteric drugs could be developed to target ACE2. At the time of the 2020 pandemic, we suggest that available ACE2 inhibitors or activators in advanced development should be tested for their ability to allosterically displace the interaction between ACE2 and the spike protein.  相似文献   
6.
7.
8.
9.
10.
Radiation therapy is a technology-driven cancer treatment modality that has experienced significant advances over the last decades, due to multidisciplinary contributions that include engineering and computing. Recent technological developments allow the use of noncoplanar volumetric modulated arc therapy (VMAT), one of the most recent photon treatment techniques, in clinical practice. In this work, an automated noncoplanar arc trajectory optimization framework designed in two modular phases is presented. First, a noncoplanar beam angle optimization algorithm is used to obtain a set of noncoplanar irradiation directions. Then, anchored in these directions, an optimization strategy is proposed to compute an optimal arc trajectory. The computational experiments considered a pool of twelve difficult head-and-neck tumor cases. It was possible to observe that, for some of these cases, the optimized noncoplanar arc trajectories led to significant treatment planning quality improvements, when compared with coplanar VMAT treatment plans. Although these experiments were done in a research environment treatment planning software (matRad), the conclusions can be of interest for a clinical setting: automated procedures can simplify the current treatment workflow, produce high-quality treatment plans, making better use of human resources and allowing for unbiased comparisons between different treatment techniques.  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