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   5024958篇
  免费   403643篇
  国内免费   18783篇
耳鼻咽喉   70510篇
儿科学   160874篇
妇产科学   130929篇
基础医学   754140篇
口腔科学   140396篇
临床医学   466091篇
内科学   918781篇
皮肤病学   121009篇
神经病学   421602篇
特种医学   196951篇
外国民族医学   989篇
外科学   751547篇
综合类   144835篇
现状与发展   37篇
一般理论   2824篇
预防医学   417441篇
眼科学   117899篇
药学   360048篇
  64篇
中国医学   16143篇
肿瘤学   254274篇
  2021年   60490篇
  2020年   40856篇
  2019年   66481篇
  2018年   81969篇
  2017年   64629篇
  2016年   71360篇
  2015年   84621篇
  2014年   119454篇
  2013年   185200篇
  2012年   146340篇
  2011年   154418篇
  2010年   137383篇
  2009年   135312篇
  2008年   137274篇
  2007年   146531篇
  2006年   153798篇
  2005年   147843篇
  2004年   147892篇
  2003年   137550篇
  2002年   125978篇
  2001年   198304篇
  2000年   195190篇
  1999年   175109篇
  1998年   76294篇
  1997年   70995篇
  1996年   69102篇
  1995年   64631篇
  1994年   58441篇
  1993年   54155篇
  1992年   128789篇
  1991年   123552篇
  1990年   118991篇
  1989年   115523篇
  1988年   106394篇
  1987年   104433篇
  1986年   98505篇
  1985年   95898篇
  1984年   77825篇
  1983年   68488篇
  1982年   51633篇
  1981年   47726篇
  1980年   44738篇
  1979年   67704篇
  1978年   53055篇
  1977年   46615篇
  1976年   43256篇
  1975年   44074篇
  1974年   48997篇
  1973年   46935篇
  1972年   43937篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
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   
15.
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   
16.
17.
18.
19.

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   
20.
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