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   4862267篇
  免费   382785篇
  国内免费   15836篇
耳鼻咽喉   69362篇
儿科学   153126篇
妇产科学   129437篇
基础医学   730072篇
口腔科学   137377篇
临床医学   447643篇
内科学   883511篇
皮肤病学   114213篇
神经病学   409600篇
特种医学   191646篇
外国民族医学   1127篇
外科学   729297篇
综合类   140038篇
现状与发展   24篇
一般理论   2860篇
预防医学   414848篇
眼科学   115479篇
药学   344379篇
  29篇
中国医学   12397篇
肿瘤学   234423篇
  2021年   56224篇
  2019年   58929篇
  2018年   74937篇
  2017年   57376篇
  2016年   63706篇
  2015年   76497篇
  2014年   111304篇
  2013年   176723篇
  2012年   135348篇
  2011年   142195篇
  2010年   128460篇
  2009年   129504篇
  2008年   128871篇
  2007年   138264篇
  2006年   145754篇
  2005年   141078篇
  2004年   141339篇
  2003年   131502篇
  2002年   121855篇
  2001年   181008篇
  2000年   178056篇
  1999年   161802篇
  1998年   74395篇
  1997年   69870篇
  1996年   68001篇
  1995年   63652篇
  1994年   57861篇
  1993年   53631篇
  1992年   121846篇
  1991年   117487篇
  1990年   112442篇
  1989年   109313篇
  1988年   101773篇
  1987年   99917篇
  1986年   95058篇
  1985年   92526篇
  1984年   76339篇
  1983年   67792篇
  1982年   51718篇
  1981年   48016篇
  1980年   45137篇
  1979年   68851篇
  1978年   54441篇
  1977年   47539篇
  1976年   44326篇
  1975年   44658篇
  1974年   51153篇
  1973年   49323篇
  1972年   46536篇
  1971年   42950篇
排序方式: 共有10000条查询结果,搜索用时 0 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