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   1522435篇
  免费   121154篇
  国内免费   3712篇
耳鼻咽喉   19732篇
儿科学   49398篇
妇产科学   43128篇
基础医学   215004篇
口腔科学   40204篇
临床医学   137117篇
内科学   306850篇
皮肤病学   34832篇
神经病学   126622篇
特种医学   58149篇
外国民族医学   464篇
外科学   228207篇
综合类   34407篇
现状与发展   3篇
一般理论   649篇
预防医学   120623篇
眼科学   33982篇
药学   106365篇
  3篇
中国医学   3498篇
肿瘤学   88064篇
  2021年   12893篇
  2019年   13563篇
  2018年   18952篇
  2017年   14406篇
  2016年   16054篇
  2015年   18191篇
  2014年   25773篇
  2013年   38448篇
  2012年   52535篇
  2011年   55582篇
  2010年   32494篇
  2009年   30992篇
  2008年   51265篇
  2007年   54238篇
  2006年   54429篇
  2005年   52976篇
  2004年   50565篇
  2003年   48100篇
  2002年   46438篇
  2001年   74019篇
  2000年   75364篇
  1999年   62666篇
  1998年   18351篇
  1997年   16492篇
  1996年   16624篇
  1995年   15791篇
  1994年   14259篇
  1993年   13419篇
  1992年   46501篇
  1991年   44175篇
  1990年   42099篇
  1989年   40135篇
  1988年   36787篇
  1987年   35947篇
  1986年   33473篇
  1985年   31979篇
  1984年   24594篇
  1983年   20751篇
  1982年   13177篇
  1981年   11766篇
  1979年   21245篇
  1978年   15127篇
  1977年   12580篇
  1976年   11797篇
  1975年   12025篇
  1974年   14371篇
  1973年   13913篇
  1972年   12886篇
  1971年   11731篇
  1970年   11151篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
A new semi-empirical formula for the evaluation of (n,(3)He) reaction cross-sections at the energy of 14.6 and 20 MeV is presented. Formula was derived using the analytical expression for the evaluation of the (3)He spectrum within the frame of pre-equilibrium exciton model. The systematics obtained is compared with the empirical formula for the (n,(3)He) reaction cross-section.  相似文献   
103.
104.
Systems of care (SOCs) have been developed throughout the country to meet the needs of children with severe emotional disturbances (SED) and their families. In these SOCs, multiple agencies and disciplines are expected to work together with informal community supports to address families' needs (Stroul & Friedman, 1986a). A review of the literature on the impact of SOCs suggests: (a) communities' service delivery systems change; and (b) children experience modest improvements in symptomatology and functioning. At the same time, little is known about (a) which components of the SOC approach, at what levels, are necessary to impact child and family outcomes; (b) the degree to which SOCs affect other family members, beyond the target child; and (c) the impact of community contexts and supports in SOCs. Future research should improve measurement of key SOC constructs, examine the relation between specific levels of implementation and outcomes for the entire family, and investigate the impact of broader community systems and supports on families within SOCs. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 655–674, 2004.  相似文献   
105.
106.
107.
Liposarcomas are extremely rare in the mediastinum. They may achieve considerable size before causing any symptoms. Mediastinal liposarcomas may invade surrounding structures like the pericardium or the superior vena cava. Complete surgical excision is the optimal treatment in resectable cases. Excision of adjacent structures like the pericardium may be needed if the tumor infiltrates them. We report on a case of a giant liposarcoma of the mediastinum involving both hemithoraces and extending into the neck, which was successfully managed by complete surgical excision.  相似文献   
108.
109.
At the time of hire, 4059 of 6522 healthcare workers required a 2-step tuberculin skin test; 114 workers (2.8%) demonstrated a boosted reaction after the second step. Boosted reactions were significantly associated with male sex and older age. A verbal history of previous tuberculin skin test results was not a reliable indicator of baseline tuberculin skin test status at the time of hire.  相似文献   
110.
BACKGROUND: An augmented reality tool for computer assisted surgery named X-Scope allows visual tracking of real anatomical structures in superposition with volume rendered CT or MRI scans and thus can be used for navigated translocation of bony segments. METHODS: In a feasibility study X-Scope was used in orthognathic surgery to control the translocation of the maxilla after Le Fort I osteotomy within a bimaxillary procedure. The situation achieved was compared with the pre-operative situation by means of cephalometric analysis on lateral and frontal cephalograms. RESULTS: The technique was successfully utilized in 5 patients. Maxillary positioning using X-Scope was accomplished accurately within a range of 1mm. The tool was used in all cases in addition to the usual intra-operative splints. A stand-alone application without conventional control does not yet seem reasonable. CONCLUSION: Augmented reality tools like X-Scope may be helpful for controlling maxillary translocation in orthognathic surgery. The application to other interventions in cranio-maxillofacial surgery such as Le Fort III osteotomy, fronto-orbital advancement, and cranial vault reshaping or repair may also be considered.  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