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   7955篇
  免费   163篇
电工技术   26篇
综合类   1篇
化学工业   837篇
金属工艺   55篇
机械仪表   53篇
建筑科学   108篇
矿业工程   4篇
能源动力   95篇
轻工业   550篇
水利工程   26篇
石油天然气   25篇
无线电   272篇
一般工业技术   426篇
冶金工业   5301篇
原子能技术   17篇
自动化技术   322篇
  2023年   25篇
  2022年   67篇
  2021年   100篇
  2020年   68篇
  2019年   65篇
  2018年   95篇
  2017年   70篇
  2016年   111篇
  2015年   83篇
  2014年   133篇
  2013年   199篇
  2012年   161篇
  2011年   210篇
  2010年   166篇
  2009年   150篇
  2008年   171篇
  2007年   152篇
  2006年   104篇
  2005年   83篇
  2004年   83篇
  2003年   87篇
  2002年   57篇
  2001年   49篇
  2000年   46篇
  1999年   205篇
  1998年   1633篇
  1997年   977篇
  1996年   601篇
  1995年   339篇
  1994年   302篇
  1993年   332篇
  1992年   47篇
  1991年   86篇
  1990年   67篇
  1989年   73篇
  1988年   75篇
  1987年   74篇
  1986年   75篇
  1985年   49篇
  1984年   8篇
  1983年   14篇
  1982年   34篇
  1981年   30篇
  1980年   34篇
  1979年   10篇
  1978年   18篇
  1977年   139篇
  1976年   299篇
  1975年   10篇
  1974年   8篇
排序方式: 共有8118条查询结果,搜索用时 0 毫秒
91.
This paper describes an automated medical record designed to allow providers to enter patient data at the point of care. The system runs on PCs and Macintoshes and uses a graphical user interface and object-oriented programming to take advantage of current mouse and pen technologies. The provider acquires all relevant patient data by pointing and clicking at selections on input screens, many of which contain anatomical drawings to help the provider quickly and accurately describe patient findings. The system also generates a grammatically correct progress note using the problem-oriented structure. Furthermore, items identified in the assessment and plans portion of the program can be ported to expert systems for medical decisions assistance or to billing systems. The system allows the provider to obtain the necessary information on a focused patient visit in less than 5 min or to enter a complete history and physical.  相似文献   
92.
The oxidation of iodide, guaiacol and 2,2'-azino-di[3-ethyl-benzthiazoline-(6)-sulphonic acid] and the iodination of tyrosyl residues in bovine serum albumin, catalysed by partly purified thyroid peroxidase, were studied. The enzyme showed pH optima with all electron donors. With the exception of guaiacol, the position of the pH optima depended upon both the electron donor and hydrogen peroxide concentrations. With increased hydrogen peroxide concentrations the optima shifted to lower pH, and with increased iodide concentration to higher pH. For monoiodotyrosine (MIT) formation in bovine serum albumin the position of the pH optimum was also dependent on the hydrogen peroxide concentrations. The position of the pH optimum of the oxidation of guaiacol was pH 9 and independent of substrate and hydrogen peroxide concentrations. It is obvious from these findings that iodination reactions must be studied under well-defined conditions.  相似文献   
93.
The immunoglobulin heavy chain (VH) gene family usage in experimental autoimmune myasthenia gravis (EAMG) model was investigated by RNA slot blot hybridization using VH gene family specific probes. Anti-acetylcholine receptor (AChR) monoclonal antibodies (mAbs) isolated from susceptible C57BL/6 and resistant BALB/c mice were found to be encoded by VH genes from at least six different families. The Vgam3.8 family was overrepresented in alpha-bungarotoxin blocking mAbs. Expression of cross-reactive idiotypes by anti-AChR mAbs was irrespective of the VH gene family usage. Strain dependent differences in susceptibility for EAMG were not reflected in an aberrant VH gene family usage of anti-AChR mAbs.  相似文献   
94.
95.
96.
97.
The synthesis and antithrombotic activity of a series of nonpeptide bicyclic thrombin inhibitors is described. We have explored the SAR with modifications to the P1 site. The introduction of arginine mimetics at the P1 site led to potent and selective thrombin inhibitors.  相似文献   
98.
STUDY DESIGN: Prospective comparative study of pain drawings with findings on lumbar spine magnetic resonance imaging. OBJECTIVES: To assess the ability of the pain drawing to predict the presence of nerve root compression. SUMMARY OF BACKGROUND DATA: Most research work has concentrated on the ability of the pain drawing to act as a screening method for psychological distress with less work directed at the influence the anatomic abnormality has on the pain drawing. METHODS: One hundred thirty-four consecutive outpatients attending for lumbar magnetic resonance imaging in the investigation of back and leg pain completed pain drawings and psychological testing immediately before the examination. The pain drawing was analyzed by previously reported criteria, and the magnetic resonance imaging was assessed independently for the presence of nerve compression by three radiologists. Multivariate stepwise discriminant analysis was used to identify patients with nerve compression on the basis of their pain drawing. RESULTS: Nerve compression was predicted by numbness in the anterolateral aspect of the foot. There was considerable overlap in the appearances of the pain drawings between patients with and without nerve compression, and the pain drawing correctly classified only 58% of patients with nerve compression. CONCLUSIONS: The pain drawing is not a good predictor of nerve compression on magnetic resonance imaging in a group of patients investigated for back and leg pain. It should be interpreted with caution and in light of the full clinical picture.  相似文献   
99.
In 1994, as a result of both programme evaluations which identified students' fears and apprehensions about their practical ability, and a review of the literature on skill acquisition, experiential skills teaching was resumed within the faculty. Having invested considerable finance into the reconstruction of a skills centre to teach skills, it is now imperative that its use be formally evaluated. Part of the evaluative process includes a review of the empirical literature on the acquisition of psychomotor skills in nursing. This paper summarizes this review.  相似文献   
100.
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