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   5681759篇
  免费   417151篇
  国内免费   16429篇
耳鼻咽喉   81626篇
儿科学   183027篇
妇产科学   153599篇
基础医学   833609篇
口腔科学   159939篇
临床医学   524797篇
内科学   1036059篇
皮肤病学   132455篇
神经病学   465744篇
特种医学   219756篇
外国民族医学   1412篇
外科学   851821篇
综合类   155792篇
现状与发展   24篇
一般理论   3135篇
预防医学   472580篇
眼科学   137134篇
药学   406786篇
  28篇
中国医学   14541篇
肿瘤学   281475篇
  2021年   57803篇
  2019年   59934篇
  2018年   78391篇
  2017年   60224篇
  2016年   67040篇
  2015年   78589篇
  2014年   113201篇
  2013年   178966篇
  2012年   165181篇
  2011年   178058篇
  2010年   138917篇
  2009年   135910篇
  2008年   162843篇
  2007年   176129篇
  2006年   182243篇
  2005年   176326篇
  2004年   175796篇
  2003年   165146篇
  2002年   153894篇
  2001年   226127篇
  2000年   224245篇
  1999年   199035篇
  1998年   79430篇
  1997年   72831篇
  1996年   70932篇
  1995年   66188篇
  1994年   60098篇
  1993年   55596篇
  1992年   148511篇
  1991年   143430篇
  1990年   139160篇
  1989年   135566篇
  1988年   125231篇
  1987年   122936篇
  1986年   116451篇
  1985年   112961篇
  1984年   89723篇
  1983年   78713篇
  1982年   55630篇
  1981年   51234篇
  1980年   48087篇
  1979年   80816篇
  1978年   61658篇
  1977年   53606篇
  1976年   50249篇
  1975年   52397篇
  1974年   60049篇
  1973年   57704篇
  1972年   54278篇
  1971年   50644篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
14.
Vestibular function laboratories utilize a multitude of diagnostic instruments to evaluate a dizzy patient. Caloric irrigators, oculomotor stimuli, and rotational chairs produce a stimulus whose accuracy is required for the patient response to be accurate. Careful attention to everything from cleanliness of equipment to threshold adjustments determine on a daily basis if patient data are going to be correct and useful. Instrumentation specifications that change with time such as speed and temperature must periodically be checked using calibrated instruments.  相似文献   
15.
16.
17.
18.

Background

Limited data exists demonstrating the efficacy of minimally invasive surgery (MIS) compared to median sternotomy (MS) for multiple valvular disease (MVD). This systematic review and meta-analysis aims to compare operative and peri-operative outcomes of MIS vs MS in MVD.

Methods

PubMed, Ovid, and Embase were searched from inception until August 2019 for randomized and observational studies comparing MIS and MS in patients with MVD. Clinical outcomes of intra- and postoperative times, reoperation for bleeding and surgical site infection were evaluated.

Results

Five observational studies comparing 340 MIS vs 414 MS patients were eligible for qualitative and quantitative review. The quality of evidence assessed using the Newcastle-Ottawa scale was good for all included studies. Meta-analysis demonstrated increased cardiopulmonary bypass time for MIS patients (weighted mean difference [WMD], 0.487; 95% confidence interval [CI], 0.365-0.608; P < .0001). Similarly, aortic cross-clamp time was longer in patients undergoing MIS (WMD, 0.632; 95% CI, 0.509-0.755; P < .0001). No differences were found in operative mortality, reoperation for bleeding, surgical site infection, or hospital stay.

Conclusions

MIS for MVD have similar short-term outcomes compared to MS. This adds value to the use of minimally invasive methods for multivalvular surgery, despite conferring longer operative times. However, the paucity in literature and learning curve associated with MIS warrants further evidence, ideally randomized control trials, to support these findings.
  相似文献   
19.
20.
ABSTRACT

Objective

To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline.  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