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   7843篇
  免费   145篇
  国内免费   2篇
电工技术   23篇
综合类   11篇
化学工业   759篇
金属工艺   36篇
机械仪表   22篇
建筑科学   68篇
矿业工程   9篇
能源动力   51篇
轻工业   247篇
水利工程   18篇
石油天然气   11篇
无线电   101篇
一般工业技术   366篇
冶金工业   6029篇
原子能技术   3篇
自动化技术   236篇
  2023年   45篇
  2022年   128篇
  2021年   160篇
  2020年   78篇
  2019年   65篇
  2018年   87篇
  2017年   67篇
  2016年   89篇
  2015年   82篇
  2014年   85篇
  2013年   145篇
  2012年   125篇
  2011年   153篇
  2010年   100篇
  2009年   90篇
  2008年   89篇
  2007年   86篇
  2006年   74篇
  2005年   62篇
  2004年   60篇
  2003年   52篇
  2002年   42篇
  2001年   15篇
  2000年   21篇
  1999年   193篇
  1998年   1928篇
  1997年   1110篇
  1996年   710篇
  1995年   388篇
  1994年   285篇
  1993年   372篇
  1992年   53篇
  1991年   47篇
  1990年   61篇
  1989年   49篇
  1988年   41篇
  1987年   45篇
  1986年   39篇
  1985年   52篇
  1984年   5篇
  1983年   13篇
  1982年   21篇
  1981年   42篇
  1980年   54篇
  1979年   8篇
  1978年   16篇
  1977年   132篇
  1976年   294篇
  1975年   15篇
  1955年   5篇
排序方式: 共有7990条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
AM Lacy 《Canadian Metallurgical Quarterly》1998,10(3):279-86; quiz 288
Due to aesthetic and periodontal factors, patients often seek treatment to close diastemata. This condition may be eliminated by either direct or indirect techniques. Indirect techniques generally require multiple visits to facilitate the placement of laminate, crown, or bridge restorations, and involve significant financial expense. Direct techniques can be economical and successful, although they present unique challenges in the achievement of satisfactory proximal contacts and contours. This article describes three clinical techniques that may be employed to treat anterior and posterior diastemata in a single appointment.  相似文献   
5.
6.
7.
The level of blood lipids and apolipoproteins in subjects being screened for abdominal aortic aneurysms have been investigated. As part of an ultrasound screening programme in a population of 65- to 75-year-olds, blood samples were collected from 1460 of 1504 subjects with a normal aorta (97.1%) and 69 of 70 patients with an abdominal aortic aneurysm > 29 mm (99%). Samples were also taken from 22 of 27 patients (81%) with an ectatic aorta (26-29 mm). Total cholesterol, HDL-cholesterol, LDL-cholesterol, Apo-AI and Apo-B levels were significantly higher in women than in men (P < 0.01). Levels of HDL-cholesterol and Apo-AI were significantly lower in patients with an abdominal aortic aneurysm than in normal subjects (P < 0.001). The mean(s.d.) body mass index was 25.1(3.9) in women and 25.5(3.2) in men with aneurysms and not significantly greater than that of normal subjects (25.2(3.61) and 25.2(3.38) respectively).  相似文献   
8.
The role of clinical pharmacology in improving the prevention and treatment of malaria is reviewed. A series of general and specific issues is discussed, concentrating on risk-benefit and cost-effectiveness. The techniques of clinical pharmacokinetics play an important role in the optimal use of drugs and this is illustrated by studies on quinine and proguanil. In discussing amodiaquine toxicity, the role of the pharmacologist and the chemist in designing out drug toxicity lends hope for producing a new generation of antimalarial drugs.  相似文献   
9.
cABL is a protooncogene, activated in a subset of human leukemias, whose protein product is a nonreceptor tyrosine kinase of unknown function. cABL has a complex structure that includes several domains and motifs found in proteins implicated in signal transduction pathways. An approach to elucidate cABL function is to identify proteins that interact directly with cABL and that may serve as regulators or effectors of its activity. To this end, a protein-interaction screen of a phage expression library was undertaken to identify proteins that interact with specific domains of cABL. An SH3-domain-containing protein has been identified that interacts with sequences in the cABL carboxyl terminus. The cDNA encoding ALP1 (amphiphysin-like protein 1) was isolated from a 16-day mouse embryo. ALP1 has high homology to BIN1, a recently cloned myc-interacting protein, and also shows significant homology to amphiphysin, a neuronal protein cloned from human and chicken. The amino terminus has homology to two yeast proteins, Rvs167 and Rvs161, which are involved in cell entry into stationary phase and cytoskeletal organization. ALP1 binds cABL in vitro and in vivo. Expression of ALP1 results in morphological transformation of NIH 3T3 fibroblasts in a cABL-dependent manner. The properties of ALP1 suggest that it may be involved in possible cytoskeletal functions of the cABL kinase. Additionally, these results provide further evidence for the importance of the cABL carboxyl terminus and its binding proteins in the regulation of cABL function.  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