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   45300篇
  免费   3178篇
  国内免费   169篇
耳鼻咽喉   496篇
儿科学   1425篇
妇产科学   1220篇
基础医学   6260篇
口腔科学   787篇
临床医学   6417篇
内科学   8755篇
皮肤病学   753篇
神经病学   4523篇
特种医学   849篇
外国民族医学   1篇
外科学   3693篇
综合类   764篇
一般理论   42篇
预防医学   5263篇
眼科学   915篇
药学   3184篇
中国医学   112篇
肿瘤学   3188篇
  2023年   247篇
  2022年   533篇
  2021年   947篇
  2020年   542篇
  2019年   881篇
  2018年   1022篇
  2017年   786篇
  2016年   873篇
  2015年   1057篇
  2014年   1418篇
  2013年   2112篇
  2012年   3183篇
  2011年   3369篇
  2010年   1696篇
  2009年   1637篇
  2008年   2968篇
  2007年   3203篇
  2006年   3261篇
  2005年   3186篇
  2004年   3099篇
  2003年   2913篇
  2002年   2687篇
  2001年   412篇
  2000年   302篇
  1999年   411篇
  1998年   505篇
  1997年   431篇
  1996年   390篇
  1995年   370篇
  1994年   278篇
  1993年   306篇
  1992年   226篇
  1991年   231篇
  1990年   199篇
  1989年   197篇
  1988年   205篇
  1987年   165篇
  1986年   145篇
  1985年   158篇
  1984年   197篇
  1983年   194篇
  1982年   242篇
  1981年   177篇
  1980年   185篇
  1979年   122篇
  1978年   110篇
  1977年   116篇
  1976年   90篇
  1975年   76篇
  1974年   84篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
43.
BACKGROUND: Little is known about parental experience and decision making with regard to premature infants requiring intensive care in developing countries. We undertook this study to characterise parents' experience of physician counselling and their role in making life-support decisions for very low-birth-weight (VLBW) (birth weight < 1 501 g) infants born in South Africa's public-sector neonatal intensive care units (NICUs). METHODS: Parents of surviving VLBW infants treated in three Johannesburg-area public hospitals and attending follow-up clinics in August 2001 were interviewed regarding their experience of perinatal counselling on outcomes (pain, survival, disability), perception of actual and optimal decision making, and satisfaction with NICU communication. RESULTS: Parents of 51 infants were interviewed. Seventy-five per cent of parents reported antenatal counselling by physicians on at least one perinatal topic (severe disability, pain, death, finances or religious/moral considerations). The majority of parents (> 60%) who received counselling thought that these topics had been discussed adequately. Most parents reported that doctors had the primary decision-making role, either without consulting them (41%) or after consulting them (37%). Joint decision making was rare (14%). Parents wanted more input in life-support decisions than they reported being given. CONCLUSION: Counselling is not consistently provided in public-sector hospitals in Johannesburg. Parents of premature infants want a larger share in NICU decision making than they currently experience. Most parents were satisfied with communication later during their infant's hospitalisation. South Africa presents a unique opportunity to study the use of advanced medical technologies in a nation with marked disparities in access to care.  相似文献   
44.
OBJECTIVE: To describe investigation of a tightly clustered outbreak of invasive group A streptococcal (GAS) disease associated with a high mortality rate in a long-term care facility (LTCF). DESIGN: Cross-sectional carriage survey and epidemiologic investigation of LTCF resident and employee cohorts. SETTING: A 104-bed community LTCF between March 1 and April 7, 2004. PATIENTS: A cohort of LTCF residents with assigned beds at the time of the outbreak. INTERVENTIONS: Reinforcement of standard infection control measures and receipt of chemoprophylaxis by GAS carriers. RESULTS: Four confirmed and 2 probable GAS cases occurred between March 16 and April 1, 2004. Four case patients died. The final case occurred during the investigation, before the patient was determined to be a GAS carrier. No case occurred during the 6 months after the intervention. Disease was caused by type emm3 GAS; 16.5% of residents and 2.4% of employees carried the outbreak strain. Disease was clustered in 1 quadrant of the LTCF and associated with nonintact skin. GAS disease or carriage was associated with having frequent personal visitors. CONCLUSIONS: Widespread carriage of a virulent GAS strain likely resulted from inadequate infection control measures. Enhanced infection control and targeted prophylaxis for GAS carriers appeared to end the outbreak. In addition to employees, regular visitors to LTCFs should be trained in hand hygiene and infection control because of the potential for extended relationships over time, leading to interaction with multiple residents, and disease transmission in such residential settings. Specific attention to prevention of skin breaks and proper wound care may prevent disease. The occurrence of a sixth case during the investigation suggests urgency in addressing severe, large, or tightly clustered outbreaks of GAS infection in LTCFs.  相似文献   
45.
46.
47.
48.
49.
50.
Deposits of dental plaque or calculus are typically quantified using planimetric techniques. However, error is introduced into a quantitative analysis of plaque deposits using these methods, since they require a significant amount of human intervention. The purpose of this study is to describe and validate a computerized imaging routine which has the potential to objectively identify material on dental roots and measure the area covered by these deposits. Dentiform teeth with simulated plaque were videorecorded. A computer routine was developed based on a flood-fill algorithm which analyzed images of the dentiform teeth and determined the amount of simulated plaque on their root surfaces. Results showed that the dentiform teeth and their simulated plaque patterns are duplicated by the imaging routine in a rapid and reliable fashion. The system shows a high degree of accuracy with an average error factor of only 0.58%. As well, the system enables precise reproducibility with an average error factor of only 0.71%.  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