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   1328377篇
  免费   95979篇
  国内免费   2894篇
耳鼻咽喉   19710篇
儿科学   40251篇
妇产科学   38823篇
基础医学   185927篇
口腔科学   39760篇
临床医学   112038篇
内科学   260397篇
皮肤病学   30177篇
神经病学   105844篇
特种医学   53841篇
外国民族医学   435篇
外科学   207606篇
综合类   30988篇
现状与发展   6篇
一般理论   438篇
预防医学   91502篇
眼科学   31333篇
药学   99874篇
  2篇
中国医学   2951篇
肿瘤学   75347篇
  2018年   11773篇
  2015年   11910篇
  2014年   16736篇
  2013年   25318篇
  2012年   33091篇
  2011年   34955篇
  2010年   20780篇
  2009年   20285篇
  2008年   33654篇
  2007年   36785篇
  2006年   37343篇
  2005年   36128篇
  2004年   35148篇
  2003年   34071篇
  2002年   33582篇
  2001年   63568篇
  2000年   65220篇
  1999年   55076篇
  1998年   13873篇
  1997年   12637篇
  1996年   12117篇
  1995年   12146篇
  1994年   11414篇
  1992年   42741篇
  1991年   41289篇
  1990年   40556篇
  1989年   39570篇
  1988年   36954篇
  1987年   36410篇
  1986年   34893篇
  1985年   33106篇
  1984年   24793篇
  1983年   20999篇
  1982年   12614篇
  1981年   11506篇
  1980年   10712篇
  1979年   23873篇
  1978年   17025篇
  1977年   14770篇
  1976年   13337篇
  1975年   15233篇
  1974年   18046篇
  1973年   17544篇
  1972年   16797篇
  1971年   15701篇
  1970年   14883篇
  1969年   14330篇
  1968年   13443篇
  1967年   11995篇
  1966年   11246篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
91.
Weltweit entstehen an Feiertagen schwere Augenverletzungen durch Feuerwerkskörper. Die Datenlage für Deutschland ist bislang unklar. Wie häufig entstehen solche Verletzungen in Deutschland, wer ist gefährdet, wie schwer sind die Verletzungen, welche Therapien erfordern sie, und wie häufig treten Begleitverletzungen auf? Deutschlandweite standardisierte Online-Umfrage an bettenführenden, notdienstleistenden Augenkliniken und Auswertung der Ergebnisse über 3 Jahre. Die Beteiligung konnte von 2016 bis 2019 von 41 auf 51 Augenkliniken gesteigert werden. Von 1356 Patienten war mehr als ein Drittel (33–39 %) minderjährig, rund 60 % 25 Jahre oder jünger und rund 60 % Bystander. Ein Viertel der Verletzungen war schwer und erforderte eine stationäre Therapie. Begleitverletzungen am Partnerauge, an Händen und Gesicht waren bei Minderjährigen häufiger als bei Erwachsenen. Bulbusrupturen wurden bei 10 Kindern und 38 Erwachsenen dokumentiert. Vor allem Minderjährige und Zuschauer müssen besser geschützt werden.  相似文献   
92.
In an article in this issue of the Hastings Center Report, Aaron Wightman and his coauthors attempt to address health care providers’ moral distress about acceding to parents’ requests to provide life‐sustaining medical treatment to children who have profound cognitive disabilities. They propose combining John Arras's relational potential standard and care ethics, and they argue that the capacity for caring relationships can provide an independent moral justification for honoring such requests. This combination is, however, unstable. Wightman et al.'s language of potential and capacity opens the possibility of substantial misinterpretation. They rely on epistemological and prognostic uncertainty to argue that reciprocity and participation may be present in the parent‐child relationship even when the child's engagement cannot be observed. The terminology suggests that these are characteristics that can be gained or lost rather than characteristics of being born within certain social practices. In contrast, Eva Feder Kittay illuminates family membership as an important social relation. Her articulation of the independent moral value of parenting stands on its own without being conjoined to Arras's position.  相似文献   
93.
Bulletin of Environmental Contamination and Toxicology - This work describes the development of an analytical protocol combining cleanup by liquid–solid extraction and GC–MS for the...  相似文献   
94.

Objectives

The aim of this study was to develop a high-fidelity minimally invasive mitral valve surgery (MIMVS) simulator.

Methods

The process of industrial serial design was applied based on pre-set requirements, acquired by interviewing experienced mitral surgeons. A thoracic torso with endoscopic and robotic access and disposable silicone mitral valve apparatus with a feedback system was developed. The feedback system was based on 4 cameras around the silicone valve and an edge detection algorithm to calculate suture depth and width. Validity of simulator measurements was assessed by comparing simulator-generated values with measurements done manually on 3-dimensional reconstructed micro-computed tomography scan of the same sutures. Independent surgeons tested the simulator between 2014 and 2018, whereupon an evaluation was done through a questionnaire.

Results

The feedback system was able to provide width and depth measurements, which were subsequently scored by comparison to pre-set target values. Depth did not significantly differ between simulator and micro-computed tomography scan measurements (P = .139). Width differed significantly (P = .001), whereupon a significant regression equation was found (P < .0001) to calibrate the simulator. After calibration, no significant difference was found (P = .865). In total, 99 surgeons tested the simulator and more than agreed with the statements that the simulator is a good method for training MIMVS, and that the mitral valve and suture placement looked and felt realistic.

Conclusions

We successfully developed a high-fidelity MIMVS simulator for endoscopic and robotic approaches. The simulator provides a platform to train skills in an objective and reproducible manner. Future studies are needed to provide evidence for its application in training surgeons.  相似文献   
95.

Background

Bone mineral density (BMD) has been found to improve after parathyroidectomy (PTX) in patients with primary hyperparathyroidism. There are few data on the effect of PTX on BMD in normocalcemic and normohormonal primary hyperparathyroidism.

Methods

A retrospective analysis of 92 primary hyperparathyroidism patients who underwent PTX between 2004 and 2012 with pre- and post-PTX dual-energy x-ray absorptiometry was performed. Within-person changes in BMD pre- and post-PTX were analyzed using log linear mixed models, stratified by biochemical status.

Results

Bone mineral density increased post-PTX in the whole cohort at the lumbar spine (+2.5%), femoral neck (+2.1%), and total hip (+1.9%) and decreased at the one-third radius (–0.9%). On comparison of BMD changes by profile, BMD increased in those with the typical profile at the lumbar spine (3.2%), femoral neck (2.9%), and total hip (2.9%) but declined at the one-third radius (–1.5%). In contrast, BMD improved only at the femoral neck (4.3%) in the normohormonal group and did not change at any site in the normocalcemic group. The typical group had a greater increase in BMD over time at the femoral neck and total hip compared with normocalcemic patients.

Conclusion

Our results indicate that the skeletal benefit of PTX was attenuated in normocalcemic and normohormonal patients, suggesting that skeletal changes after PTX may depend on biochemical profile.  相似文献   
96.
97.
This review forms part of a series of annual updates that summarize the evidence base for atopic eczema (AE). It provides a summary of key findings from 25 systematic reviews that were published or indexed during 2017, and focuses on the treatment and prevention of AE. There is high‐quality evidence to demonstrate that dupilumab is better than placebo for the treatment of AE, is not associated with a higher incidence of adverse effects and does not increase the risk of infection compared with placebo; however, comparison studies with other systemic treatments are necessary. Topical tofacitinib is a promising treatment for mild–moderate AE, but currently lacks sufficient evidence from well‐designed randomized controlled trials (RCTs) comparing with other active treatments. Topical doxepin may be effective for pruritus in AE, but available studies have short follow‐up periods and longer‐term outcomes are needed. Bleach baths were no more effective than water baths alone at reducing AE severity. Topical antibiotics cannot be recommended for infected AE, owing to insufficient evidence of benefit. There is little comparison of different emollients in RCTs, but overall evidence indicates that they reduce AE severity, are steroid‐sparing and lead to better outcomes in combination with topical corticosteroids (TCS) than TCS alone. No clear benefit was demonstrated for vitamin D/C/E supplementation in pregnancy for eczema prevention.  相似文献   
98.

Objectives

Studies have shown that having a baseline mammogram, the first screening mammogram, available for comparison at the time of interpreting a subsequent mammogram significantly decreases the potential of a false-positive examination. Our aim was to evaluate knowledge of and perception about the significance of baseline mammograms in those women undergoing screening mammography.

Materials and Methods

A cross-sectional prospective survey study was conducted in women without a history of breast cancer presenting for their screening mammogram. Respondents were surveyed anonymously between March and April 2017. The questionnaire was developed by primary care providers and radiologists and pretested for readability and clarity.

Results

In all, 401 women (87% white, 93% educated beyond high school) completed surveys in which 77% of women reported having yearly mammograms, 31% reported having a history of an abnormal mammogram, and 45% had not heard the term baseline mammogram. Of those who had heard the term, the most commonly reported source was their primary care provider (31%). Although 74% chose the correct definition of a baseline mammogram, 67% did not think that a baseline mammogram was important for decreasing associated cost, time, and discomfort due to the number of mammograms incorrectly read as abnormal.

Conclusion

In a group of educated women who routinely get mammograms, almost one-half had not heard the term baseline mammogram. Furthermore, most women did not think baseline mammography was important for decreasing associated cost, time, and discomfort due to mammograms incorrectly read as abnormal. This study suggests that efforts to improve women’s understanding of baseline mammograms and their importance are warranted, with greatest opportunity for health care providers and radiologists.  相似文献   
99.
Due to the high relapse rates and the rise of predisposing factors, the need for curing onychomycosis is paramount. To effectively address onychomycosis, the definition of cure used in a clinical setting should be agreed upon and applied homogeneously across therapies (e.g. oral, topical and laser treatments). In order to determine what is or what should be used to define cure in a clinical setting, a literature search was conducted to identify methods used to evaluate treatment success. The limitations, strengths, prevalence and utility of each outcome measure were investigated. Seven ways to measure treatment success were identified; mycological cure, patient/investigator assessments, complete cure, quality of life instruments, severity indexes, clinical cure and temporary clearance. Despite its shortcomings, mycological cure is the most objective and consistent outcome measure used across onychomycosis studies. It is suggested that diagnostic goals of onychomycosis should be used to define cure in a clinical setting. Modifications to outcome measures such as incorporating molecular‐based techniques could be a future avenue to explore.  相似文献   
100.
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