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   3223902篇
  免费   240803篇
  国内免费   5488篇
耳鼻咽喉   47321篇
儿科学   102362篇
妇产科学   85460篇
基础医学   453838篇
口腔科学   93118篇
临床医学   290326篇
内科学   620274篇
皮肤病学   68745篇
神经病学   264782篇
特种医学   128942篇
外国民族医学   1095篇
外科学   489258篇
综合类   72801篇
现状与发展   2篇
一般理论   1225篇
预防医学   248998篇
眼科学   76795篇
药学   245059篇
  11篇
中国医学   6596篇
肿瘤学   173185篇
  2018年   33674篇
  2017年   26116篇
  2016年   29415篇
  2015年   33072篇
  2014年   46270篇
  2013年   69519篇
  2012年   94807篇
  2011年   99694篇
  2010年   58841篇
  2009年   55508篇
  2008年   94099篇
  2007年   100823篇
  2006年   102039篇
  2005年   99249篇
  2004年   95571篇
  2003年   92252篇
  2002年   90556篇
  2001年   152092篇
  2000年   157407篇
  1999年   132999篇
  1998年   37287篇
  1997年   33513篇
  1996年   33128篇
  1995年   31704篇
  1994年   29618篇
  1993年   27654篇
  1992年   105143篇
  1991年   101352篇
  1990年   98246篇
  1989年   94869篇
  1988年   87731篇
  1987年   86047篇
  1986年   81587篇
  1985年   77735篇
  1984年   58166篇
  1983年   49432篇
  1982年   29355篇
  1981年   25985篇
  1979年   54312篇
  1978年   37722篇
  1977年   32397篇
  1976年   29762篇
  1975年   32141篇
  1974年   39068篇
  1973年   37162篇
  1972年   35041篇
  1971年   32563篇
  1970年   30575篇
  1969年   28660篇
  1968年   26000篇
排序方式: 共有10000条查询结果,搜索用时 114 毫秒
71.
72.
The clinical outcome and appropriate management for patients showing 'borderline changes' on allograft biopsy after renal transplantation is still controversial. In an attempt to identify predictive factors of clinical outcome of patients with such lesions, we reviewed the clinical course of 91 patients with borderline changes. Multivariate analysis revealed significant and independent effects of histological stage (i + t < or = or > 2) and time to borderline changes (< or = or > 3 months after transplant) on serum creatinine levels at 1 year from borderline changes episodes (respectively, p = 0.04 and p = 0.02) and only a significant effect of time to borderline changes on serum creatinine levels at 2 years (p = 0.005). Renal function at 1 year and 2 years as 5- and 8-year graft survival were not significantly different in the group of patients treated with antirejection therapy (T group, n = 49) compared with the untreated group (UT group, n = 42). This study strongly suggests that borderline changes with histological score (i + t) > 2 and late episodes of borderline changes should be considered to be of poor prognosis.  相似文献   
73.
74.
Endoscopic clips have been used mainly for control of gastrointestinal (GI) bleeding and occasionally for closure of GI perforations. However, closure of spontaneous esophageal perforation (Boerhaave's syndrome) by clipping has not been reported. We described successful non-surgical closure of spontaneous esophageal perforation by endoscopic clipping in a patient with bilateral pyopneumothorax and septicemia.  相似文献   
75.
76.
77.
78.
79.
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   
80.
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