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   2278414篇
  免费   168624篇
  国内免费   3682篇
耳鼻咽喉   33517篇
儿科学   77697篇
妇产科学   65217篇
基础医学   328524篇
口腔科学   63397篇
临床医学   197952篇
内科学   446889篇
皮肤病学   48983篇
神经病学   177762篇
特种医学   90005篇
外国民族医学   973篇
外科学   350706篇
综合类   49081篇
现状与发展   1篇
一般理论   632篇
预防医学   171039篇
眼科学   51962篇
药学   171416篇
  3篇
中国医学   4406篇
肿瘤学   120558篇
  2018年   22331篇
  2016年   18832篇
  2015年   21445篇
  2014年   29829篇
  2013年   45640篇
  2012年   62516篇
  2011年   66671篇
  2010年   39718篇
  2009年   37662篇
  2008年   64153篇
  2007年   69207篇
  2006年   69878篇
  2005年   68268篇
  2004年   66341篇
  2003年   64196篇
  2002年   63133篇
  2001年   105758篇
  2000年   109217篇
  1999年   92952篇
  1998年   26151篇
  1997年   23500篇
  1996年   23879篇
  1995年   22643篇
  1994年   21434篇
  1993年   19864篇
  1992年   74445篇
  1991年   73141篇
  1990年   71733篇
  1989年   68999篇
  1988年   64021篇
  1987年   62915篇
  1986年   59284篇
  1985年   56801篇
  1984年   42685篇
  1983年   36389篇
  1982年   21558篇
  1981年   19342篇
  1980年   17746篇
  1979年   39329篇
  1978年   27500篇
  1977年   23641篇
  1976年   22265篇
  1975年   24258篇
  1974年   28498篇
  1973年   27454篇
  1972年   25783篇
  1971年   23733篇
  1970年   22269篇
  1969年   20860篇
  1968年   19381篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
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   
62.
Leocani  L.  Comi  G. 《Neurological sciences》2006,27(1):s27-s29
Neurological Sciences - Brain plasticity, intended as the pattern of functional and structural changes in responses to environmental physiological or pathological events, is underlined by several...  相似文献   
63.
64.
AIM: The intention was to investigate cerebrospinal fluid pressure (CSFP) and volume of cerebrospinal fluid (CSF) drained during and after thoracic- and thoracoabdominal aneurysm repair. The findings were related to the occurrence of postoperative neurologic deficits. METHODS: Twenty-nine patients (12 with thoracic and 17 with thoracoabdominal aortic aneurysm) were operated without shunting or extracorporeal circulation. For monitoring of CSFP an intrathecal catheter was placed in all patients. The volume of CSF withdrawn intraoperatively, on the day of operation as well as on the 1st and 2nd postoperative day was recorded. RESULTS: Twenty-six patients had no postoperative neurologic sequelae. One patient had postoperative paraplegia while 2 had paraparesis. The three patients with neurologic sequelae had higher CSFP intraoperatively than those without neurologic symptoms (P=0.04). Median CSFP during aortic cross-clamping was 19 mmHg and 10 mmHg and the median volumes of CSF drained on the day of operation 210 and 85 mL in the two groups, respectively. There was a significant positive correlation between CSFP and central venous pressure. CONCLUSIONS: A higher intraoperative CSFP was observed in patients with neurologic sequelae following thoracic- and thoracoabdominal aneurysm repair. Further, there was a tendency of higher volumes of CSF drained in this group of patients. Although, the series is too small to allow firm conclusions, it supports the view that CSFP monitoring and drainage is beneficial during thoracic- and thoracoabdominal aneurysm repair.  相似文献   
65.
66.
67.
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   
68.
69.
70.
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   
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