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   61600篇
  免费   6001篇
  国内免费   310篇
耳鼻咽喉   657篇
儿科学   2048篇
妇产科学   1606篇
基础医学   8145篇
口腔科学   1095篇
临床医学   8410篇
内科学   13516篇
皮肤病学   1390篇
神经病学   6798篇
特种医学   1310篇
外科学   5805篇
综合类   300篇
现状与发展   1篇
一般理论   43篇
预防医学   6217篇
眼科学   1274篇
药学   4110篇
中国医学   136篇
肿瘤学   5050篇
  2024年   169篇
  2023年   1144篇
  2022年   1515篇
  2021年   2624篇
  2020年   1746篇
  2019年   1914篇
  2018年   2582篇
  2017年   2278篇
  2016年   2379篇
  2015年   2543篇
  2014年   3214篇
  2013年   3858篇
  2012年   4784篇
  2011年   4785篇
  2010年   2884篇
  2009年   2681篇
  2008年   3659篇
  2007年   3578篇
  2006年   3269篇
  2005年   2950篇
  2004年   2698篇
  2003年   2403篇
  2002年   2188篇
  2001年   426篇
  2000年   255篇
  1999年   427篇
  1998年   581篇
  1997年   524篇
  1996年   488篇
  1995年   391篇
  1994年   392篇
  1993年   301篇
  1992年   223篇
  1991年   192篇
  1990年   131篇
  1989年   153篇
  1988年   138篇
  1987年   131篇
  1986年   118篇
  1985年   99篇
  1984年   122篇
  1983年   94篇
  1982年   111篇
  1981年   83篇
  1980年   82篇
  1979年   43篇
  1978年   46篇
  1977年   46篇
  1976年   28篇
  1975年   28篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Despite orientation and mobility (O&M) being a significant factor determining quality of life of people with low vision or blindness, there are no gold standard measures or agreement on how to measure O&M performance. In the first part of this systematic review, an inventory of O&M outcome measures used by recent studies to assess the performance of orientation and/or mobility of adults with vision impairment (low vision and blindness) is presented. A wide variety of O&M outcome measures have been implemented in different fields of study, such as epidemiologic research and interventional studies evaluating training, assistive technology, vision rehabilitation and vision restoration. The most frequent aspect of outcome measures is efficiency such as time, distance, speed and percentage of preferred walking speed, followed by obstacle contacts and avoidance, and dis/orientation and veering. Other less commonly used aspects are target identification, safety and social interaction and self-reported outcome measures. Some studies employ sophisticated equipment to capture and analyse O&M performance in a laboratory setting, while others carry out their assessment in real-world indoor or outdoor environments. In the second part of this review, the appropriateness of implementing the identified outcome measures to assess O&M performance in clinical and functional O&M practice is evaluated. Nearly a half of these outcome measures meet all four criteria of face validity (either clinical or functional), responsiveness, reliability and feasibility and have the potential to be implemented in clinical or functional O&M practice. The findings of this review confirm the complicated and dynamic nature of O&M. Multiple measures are required in any evaluation of O&M performance to facilitate holistic assessment of O&M abilities and limitations of each individual.  相似文献   
2.
3.
Abstract

Supporting patients in making informed healthcare decisions is a cornerstone of ethical medical practice. Surgeons frequently draw for and show images to patients when consenting them for operations but the value of this practice in informed decision-making is unclear. An audit was conducted in a General Surgery Department. 244 patients completed questionnaires on the value of visual materials when giving consent for surgery. The complexity of the operations was classified into “simple”, “moderate” or “complex”. 100% of patients felt they had given informed consent to surgery. 62% of patients received at least one form of visual material during the consenting process. All patients who received a drawing, and 99% of those provided with other images, valued these resources. Visual materials were considered more useful to patients when giving consent for moderate or complex operations than simple ones. Approximately one third of patients who did not receive visual materials would have appreciated these when making an informed decision. This research highlights the value of surgeons drawing for, and providing other visual resources to, their patients as part of the consent process. There is a role for further research and training materials in drawing skills for surgeons.  相似文献   
4.
5.
6.

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   
7.
8.
9.

Background

Rosacea is a chronic inflammatory skin condition whose etiology has been linked to mast cells and the antimicrobial peptide cathelicidin LL-37. Individuals with refractory disease have demonstrated clinical benefit with periodic injections of onabotulinum toxin, but the mechanism of action is unknown.

Objectives

To investigate the molecular mechanism by which botulinum toxin improves rosacea lesions.

Methods

Primary human and murine mast cells were pretreated with onabotulinum toxin A or B or control. Mast cell degranulation was evaluated by β-hexosaminidase activity. Expression of botulinum toxin receptor Sv2 was measured by qPCR. The presence of SNAP-25 and VAMP2 was established by immunofluorescence. In vivo rosacea model was established by intradermally injecting LL-37 with or without onabotulinum toxin A pretreatment. Mast cell degranulation was assessed in vivo by histologic counts. Rosacea biomarkers were analyzed by qPCR of mouse skin sections.

Results

Onabotulinum toxin A and B inhibited compound 48/80-induced degranulation of both human and murine mast cells. Expression of Sv2 was established in mouse mast cells. Onabotulinum toxin A and B increased cleaved SNAP-25 and decreased VAMP2 staining in mast cells respectively. In mice, injection of onabotulinum toxin A significantly reduced LL-37-induced skin erythema, mast cell degranulation, and mRNA expression of rosacea biomarkers.

Conclusions

These findings suggest that onabotulinum toxin reduces rosacea-associated skin inflammation by directly inhibiting mast cell degranulation. Periodic applications of onabotulinum toxin may be an effective therapy for refractory rosacea and deserves further study.  相似文献   
10.
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