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   1368401篇
  免费   103408篇
  国内免费   6611篇
耳鼻咽喉   17072篇
儿科学   44067篇
妇产科学   36715篇
基础医学   201328篇
口腔科学   36587篇
临床医学   133940篇
内科学   262984篇
皮肤病学   26676篇
神经病学   113143篇
特种医学   49294篇
外国民族医学   381篇
外科学   187501篇
综合类   34746篇
现状与发展   8篇
一般理论   462篇
预防医学   116770篇
眼科学   29977篇
药学   102619篇
  30篇
中国医学   5252篇
肿瘤学   78868篇
  2021年   12782篇
  2019年   12781篇
  2018年   17540篇
  2017年   13471篇
  2016年   14311篇
  2015年   16838篇
  2014年   22860篇
  2013年   33949篇
  2012年   46867篇
  2011年   49682篇
  2010年   29000篇
  2009年   26474篇
  2008年   44593篇
  2007年   46794篇
  2006年   46866篇
  2005年   44949篇
  2004年   42604篇
  2003年   40395篇
  2002年   39075篇
  2001年   61453篇
  2000年   63116篇
  1999年   52856篇
  1998年   14976篇
  1997年   13661篇
  1996年   13453篇
  1995年   12785篇
  1994年   11920篇
  1993年   11089篇
  1992年   41746篇
  1991年   40905篇
  1990年   39554篇
  1989年   37434篇
  1988年   34685篇
  1987年   33786篇
  1986年   32230篇
  1985年   30693篇
  1984年   23057篇
  1983年   19606篇
  1982年   11758篇
  1979年   20813篇
  1978年   14816篇
  1977年   12064篇
  1976年   11877篇
  1975年   12111篇
  1974年   14800篇
  1973年   14472篇
  1972年   13357篇
  1971年   12418篇
  1970年   11485篇
  1969年   10410篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
BACKGROUND: Stressful conditions lead to formation of excessive free radicals, and lipid peroxidation is one of the major outcomes of free radical-mediated injury that directly damages membranes and generates a number of secondary products. OBJECTIVES: To determine the levels of malondialdehyde, an end product of lipid peroxidation, according to demographic and occupational variables in workers of a prehospital emergency service and to analyse the relationship between malondialdehyde levels and burnout. MATERIAL AND METHODS: One hundred and eleven healthy workers of a prehospital emergency service and eighty aged-matched healthy individuals of both sexes as a control group were surveyed. Malondialdehyde levels were measured by the Bull and Marnett method. To measure burnout, the Maslach Burnout Inventory was used. RESULTS: Professional category is associated with lipid peroxidation and burnout levels (Malondialdehyde levels were: physicians 338.10+/-14.47, nurses 329.17+/-12.62 and technicians 296.74+/-14.28; burnout levels were: physicians 41.29+/-3.59, nurses 37.38+/-6.05 and technicians 35.33+/-5.87). Working at night and in the evening increased malondialdehyde and burnout levels. Malondialdehyde levels increase with age. No significant variations with respect to sex were detected. Significant variations in malondialdehyde levels were detected between singles (303.13+/-12.74) and married people (344.43+/-13.43) but not with respect to divorcees (326.44+/-11.74). Significant differences were detected in erythrocyte malondialdehyde levels between smokers (341.37+/-17.09) and nonsmokers (302.21+/-12.38), but not for alcohol consumption. CONCLUSIONS: These findings suggest a positive correlation between malondialdehyde, a biomarker of lipid peroxidation and occupational stress, as estimated by elements of the Maslach Burnout Inventory, and oxidative stress.  相似文献   
73.
74.
The aim of the present study was to investigate the long-term incidence rate of Lyme borreliosis and, additionally, to determine whether a correlation exists between climatic factors and summer-season variations in the incidence of Lyme borreliosis. Climatic variability acts directly on tick population dynamics and indirectly on human exposure to Lyme borreliosis spirochetes. In this study, conducted in primary healthcare clinics in southeastern Sweden, electronic patient records from 1997–2003 were searched for those that fulfilled the criteria for erythema migrans. Using a multilevel Poisson regression model, the influence of various climatic factors on the summer-season variations in the incidence of erythema migrans were studied. The mean annual incidence rate was 464 cases of erythema migrans per 100,000 inhabitants. The incidence was significantly higher in women than in men, 505 and 423 cases per 100,000 inhabitants, respectively (p<0.001). The summer-season variations in the erythema migrans incidence rate correlated with the monthly mean summer temperatures (incidence rate ratio 1.12; p<0.001), the number of winter days with temperatures below 0°C (incidence rate ratio 0.97; p<0.001), the monthly mean summer precipitation (incidence rate ratio 0.92; p<0.05), and the number of summer days with relative humidity above 86% (incidence rate ratio 1.04; p<0.05). In conclusion, Lyme borreliosis is highly endemic in southeastern Sweden. The climate in this area, which is favourable not only for human tick exposure but also for the abundance of host-seeking ticks, influences the summer-season variations in the incidence of Lyme borreliosis.  相似文献   
75.
76.
77.
Primary chemotherapy administered to breast cancer patientsis the best model to identify baseline features able to predictwhich patients may be most likely to benefit or not from a cytotoxicregimen. In the March issue of Annals of Oncology two papersevaluated the predictive role of immunohistochemical p53 expressionon  相似文献   
78.
79.
80.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  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