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   7917篇
  免费   479篇
  国内免费   31篇
耳鼻咽喉   120篇
儿科学   244篇
妇产科学   102篇
基础医学   1096篇
口腔科学   805篇
临床医学   545篇
内科学   1912篇
皮肤病学   122篇
神经病学   526篇
特种医学   227篇
外国民族医学   2篇
外科学   726篇
综合类   46篇
一般理论   3篇
预防医学   823篇
眼科学   117篇
药学   566篇
中国医学   42篇
肿瘤学   403篇
  2023年   71篇
  2022年   180篇
  2021年   265篇
  2020年   170篇
  2019年   223篇
  2018年   273篇
  2017年   190篇
  2016年   230篇
  2015年   263篇
  2014年   335篇
  2013年   416篇
  2012年   655篇
  2011年   644篇
  2010年   373篇
  2009年   310篇
  2008年   473篇
  2007年   471篇
  2006年   412篇
  2005年   347篇
  2004年   294篇
  2003年   250篇
  2002年   228篇
  2001年   135篇
  2000年   153篇
  1999年   138篇
  1998年   68篇
  1997年   61篇
  1996年   49篇
  1995年   31篇
  1994年   31篇
  1993年   22篇
  1992年   63篇
  1991年   52篇
  1990年   50篇
  1989年   54篇
  1988年   54篇
  1987年   38篇
  1986年   40篇
  1985年   47篇
  1984年   37篇
  1983年   21篇
  1982年   15篇
  1981年   20篇
  1980年   20篇
  1979年   14篇
  1978年   14篇
  1977年   15篇
  1976年   18篇
  1975年   17篇
  1968年   12篇
排序方式: 共有8427条查询结果,搜索用时 500 毫秒
11.
12.
A case of Bonnet syndrome associated with blindness due to bilateral eye disease and a posterior parasagittal meningioma is reported. It is assumed that visual afferent deprivation alone is not enough to produce the syndrome and that, in most instances, a 'cerebral factor' must be operative if hallucinoses are to occur. The distinction between hallucinosis and hallucinations is favored and a common neural circuit for the mediation of hallucinotic imageries in general is suggested. One should not immediately put the blame on obvious eye or visual pathways affections when facing cases of Bonnet syndrome, as they are not likely to explain the complex array of images perceived by any given patient. On the contrary, the possibility of a clinically covert intracranial disease should be always raised and intensively looked for.  相似文献   
13.
Background. The European Community Respiratory Health Survey (ECRHS) questionnaire was planned to answer questions about the distribution of asthma. Our objective was to determine the cultural equivalence of the ECRHS into the Brazilian-Portuguese language. Methods. We translated the ECRHS according to international criteria. Results. Small cultural adaptations were necessary. Among the 80 participating patients, the Cronbach indices were higher (0.98-1.00) and the Kappa indices varied from 0.77 to 1.00. Conclusion. The study suggests that the Brazilian version of the ECRHS is conceptually equivalent to the original and similarly reliable and may be used in international studies involving Portuguese-speaking respiratory patients.  相似文献   
14.

Background  

Due to marginalization, trafficking violence, conflicts with the police and organic and social psychological problems associated with the drug, crack is one of the most devastating drugs currently in use. However, there is evidence that some users manage to stay alive and active while using crack cocaine for many years, despite the numerous adversities and risks involved with this behavior. In this context, the aim of the present study was to identify the strategies and tactics developed by crack users to deal with the risks associated with the culture of use by examining the survival strategies employed by long-term users.  相似文献   
15.
16.
17.
An important aspect of preventive medicine is to identify subjects at risk as soon as possible, so preventive strategies can be introduced at early ages. The justification for this strategy is twofold: firstly, the assumption that children maintain a particular high value of a risk factor for disease throughout life; and secondly, the assumption that lowering the level of the risk factor in early life will have a greater impact on the disease than will risk factor changes in later life. In epidemiology the analysis of such factors over time is referred to as tracking. Tracking analysis has been applied to risk factors for cardiovascular diseases (CVD) in pediatric years. The aims of this study were: I) to analyze the stability of biological risk factors [high blood pressure (BP), high percentage of fat mass (%FM) and high total cholesterol (TC)] and lifestyle risk factors [low physical activity index (PAI)] in isolation; and II) to analyze the stability of zero, one, two or three biological risk factors. There were two evaluations in 692 children and adolescents (325 boys and 367 girls), aged between 8 and 15 years. The quartiles, adjusted for age and gender, were the criterion used to identify subjects with biological risk factors (fourth quartile) and with lifestyle risk factors (first quartile) for CVD. The stability was calculated through the relative frequency of subjects who maintained or changed quartile between the two evaluations. There is stability for biological risk factors as well as for behavioral and/or lifestyle risk factors. However, the highest stability is seen in biological risk factors.  相似文献   
18.
The effects of HgCl2 on the epidermis of Trichomycterus brasiliensis were studied by histological, histochemical, and ultrastructural methods. First, the normal organization of the tissue was described in order to study the HgCl2 effects on the skin structure. The epithelial cells presented a typical structural organization found in many fishes. Basically five types of cells could be detailed: goblet cells, club cells, germinative stratum cells, intermediate layer cells, and epithelial cells in the superficial layer. The goblet cells in the superficial layer present evidence of secretory activity by positive histochemical reactions. In cells exposed to HgCl2, different morphological alterations were observed in the epithelium structure, such as an increase in the lymphocyte number, hypertrophied epithelial cells at the surface, modified taste buds, obstruction of the goblet cells pore, and high cellular proliferation. Moreover, the chemical nature of the goblet cells was not modified by the presence of the HgCl2 dissolved in water. All animals died within 24 hr after the contamination with inorganic mercury at concentrations of 0.2 and 0.1 mg HgCl2/liter.  相似文献   
19.
20.
The authors describe their experience with methyl tertiary butyl ether (MTBE) in a larger series of patients than previously reported in order to acquaint physicians with both its effectiveness for dissolution of common bile duct calculi and the limitations of its use. Ten patients with 13 biliary calculi underwent percutaneous stone dissolution treatment with the experimental cholesterol solvent, MTBE. Three stones completely dissolved within 30 minutes, seven were reduced in size, and three were visibly unaffected. All stones not completely dissolved were easily extracted by means of a stone basket except for one in a patient taken to surgery. Although MTBE perfusion is an effective technique for management of biliary calculi, practitioners should be aware that its use is quite time consuming and its odor difficult to control.  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