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   4357119篇
  免费   338436篇
  国内免费   14718篇
耳鼻咽喉   60291篇
儿科学   139395篇
妇产科学   114197篇
基础医学   666473篇
口腔科学   117985篇
临床医学   396858篇
内科学   790138篇
皮肤病学   107712篇
神经病学   368187篇
特种医学   169427篇
外国民族医学   753篇
外科学   655983篇
综合类   121265篇
现状与发展   24篇
一般理论   2614篇
预防医学   360276篇
眼科学   100873篇
药学   307509篇
  26篇
中国医学   11933篇
肿瘤学   218354篇
  2021年   56140篇
  2020年   35799篇
  2019年   58781篇
  2018年   74345篇
  2017年   56963篇
  2016年   63076篇
  2015年   76041篇
  2014年   110240篇
  2013年   175762篇
  2012年   124146篇
  2011年   128860篇
  2010年   125827篇
  2009年   127561篇
  2008年   115087篇
  2007年   122352篇
  2006年   131173篇
  2005年   125257篇
  2004年   126574篇
  2003年   116783篇
  2002年   106032篇
  2001年   166930篇
  2000年   162008篇
  1999年   148658篇
  1998年   71655篇
  1997年   67602篇
  1996年   65621篇
  1995年   61041篇
  1994年   54965篇
  1993年   51009篇
  1992年   106611篇
  1991年   101376篇
  1990年   97236篇
  1989年   94810篇
  1988年   87137篇
  1987年   85304篇
  1986年   80192篇
  1985年   78348篇
  1984年   65393篇
  1983年   58195篇
  1982年   47187篇
  1981年   43855篇
  1980年   41072篇
  1979年   55100篇
  1978年   44752篇
  1977年   39978篇
  1976年   36836篇
  1975年   36804篇
  1974年   39608篇
  1973年   37749篇
  1972年   35358篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
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   
994.
995.
996.
997.
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   
998.
999.
CONTEXT: Although the nonmedical use of stimulant drugs such as cocaine and methamphetamine is increasingly common in many rural areas of the United States, little is known about the health beliefs of people who use these drugs. PURPOSE: This research describes illicit stimulant drug users' views on health and health-related concepts that may affect their utilization of health care services. METHODS: A respondent-driven sampling plan was used to recruit 249 not-in-treatment, nonmedical stimulant drug users who were residing in 3 rural counties in west central Ohio. A structured questionnaire administered by trained interviewers was used to collect information on a range of topics, including current drug use, self-reported health status, perceived need for substance abuse treatment, and beliefs about health and health services. FINDINGS: Participants reported using a wide variety of drugs nonmedically, some by injection. Alcohol and marijuana were the most commonly used drugs in the 30 days prior to the interview. Powder cocaine was used by 72.3% of the sample, crack by 68.3%, and methamphetamine by 29.7%. Fair or poor health status was reported by 41.3% of the participants. Only 20.9% of the sample felt they needed drug abuse treatment. Less than one third of the sample reported that they would feel comfortable talking to a physician about their drug use, and 65.1% said they preferred taking care of their problems without getting professional help. CONCLUSIONS: Stimulant drug users in rural Ohio are involved with a range of substances and hold health beliefs that may impede health services utilization.  相似文献   
1000.
PURPOSE: In children with locally advanced or recurrent malignant tumours, prognosis can be improved by regional deep hyperthermia (RHT) in combination with platin-based chemotherapy. However, because of the increasing number of patients that achieve long-time remission with this therapy, it is necessary to evaluate long-term sequelae of thermochemotherapy. During the years 1993-2004 one has observed avascular osteonecrosis (AON) of the femoral head after RHT in seven children with pelvic germ cell tumours or rhabdomyosarcomas. METHODS: Although AON may develop in patients with malignancies treated with chemo- or radiotherapy alone, RHT might nevertheless contribute to the occurrence of AON. In order to determine potential risk factors for AON after RHT, this study analysed the relationship of AON to the patient's age, medical history and treatment parameters such as thermal dose equivalent and power output. RESULTS AND CONCLUSIONS: In the present study AON was associated with young age as well as intensity of hyperthermia indicated by high power levels that exceed 20 W per kg body weight and/or application of eight or more heat sessions as well as additional radiotherapy. Based on this observation, it was assumed that an optimized three dimensional thermal field modelling may be helpful to avoid hazardous temperatures in the femoral heads during RHT treatment and to reduce AON of the femoral heads.  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