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   11414篇
  免费   722篇
  国内免费   60篇
耳鼻咽喉   191篇
儿科学   183篇
妇产科学   202篇
基础医学   1724篇
口腔科学   1023篇
临床医学   955篇
内科学   2613篇
皮肤病学   252篇
神经病学   754篇
特种医学   235篇
外科学   1334篇
综合类   41篇
一般理论   5篇
预防医学   1177篇
眼科学   116篇
药学   886篇
中国医学   147篇
肿瘤学   358篇
  2023年   136篇
  2022年   236篇
  2021年   449篇
  2020年   291篇
  2019年   383篇
  2018年   477篇
  2017年   322篇
  2016年   340篇
  2015年   395篇
  2014年   513篇
  2013年   676篇
  2012年   928篇
  2011年   1082篇
  2010年   510篇
  2009年   415篇
  2008年   646篇
  2007年   673篇
  2006年   575篇
  2005年   491篇
  2004年   398篇
  2003年   332篇
  2002年   337篇
  2001年   214篇
  2000年   220篇
  1999年   170篇
  1998年   56篇
  1997年   51篇
  1996年   28篇
  1995年   35篇
  1994年   47篇
  1993年   33篇
  1992年   92篇
  1991年   55篇
  1990年   61篇
  1989年   60篇
  1988年   39篇
  1987年   30篇
  1986年   32篇
  1985年   32篇
  1984年   23篇
  1983年   16篇
  1980年   20篇
  1979年   16篇
  1978年   22篇
  1976年   19篇
  1975年   19篇
  1973年   22篇
  1971年   21篇
  1970年   17篇
  1969年   18篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
141.
Biliary endoscopic drainage using metallic self-expanded stents has become a well-established method for palliative treatment of malignant biliary obstruction. However, its occlusion, mainly by tumor overgrowth, is still the main complication without a standard treatment. We here describe a new method of treatment for biliary metallic stent occlusion, through the echo guided biliary drainage. We present a 68-year-old patient with metastatic pancreatic cancer previously treated for jaundice with ERCP and self-expandable metallic stent insertion. Four weeks later, the patient developed jaundice and symptoms of gastric outlet obstruction. A new ERCP confirmed obstruction of the second portion of the duodenum, due to diffuse tumor growth. EUS was performed, and the previous metal biliary stent was seen occluded at the distal portion in the common bile duct. A EUS-guided choledocododenostomy was performed and then, an overlapping self-expanding metal enteral stent was placed through the malignant obstruction. There were no early complications and the procedure was also clinically effective in relieving jaundice and gastric outlet obstruction symptoms. If ERCP fails in the management of occluded biliary metallic stents, EUS biliary drain can provide effective biliary decompression and should be considered an alternative to other endoscopic techniques.  相似文献   
142.
The P300 plays a key role as a method for monitoring and evaluating dementia, including Alzheimer's disease.Objective: The goal of this study was to search for articles which analyzed P300 latency and amplitude values in Alzheimer's disease.Methods: We searched in the following databases: Web of Science, Pub Med, Psyc Info, Medline, Biological Abstracts and Scielo using the following keywords: speed of information processing, processing speed, information processing, aged, older, elderly, older people, alzheimer dementia, alzheimer disease, Alzheimer and cross-references of selected articles.Results: We found eight studies matching the inclusion criteria. These studies showed that there is a consensus on a P300 latency increase of elderly patients with Alzheimer's disease compared with subjects without the disease. However, it appears that, with respect to the P300 amplitude, there is still no consensus; however, it may be related to different methodological variables adopted in the reviewed studies.Conclusion: There is a need to standardize the variables involved in P300 measurement for senior citizens with Alzheimer's disease in order to be able to compare P300 latency and amplitude values for this population.  相似文献   
143.
144.
Cardiac remodeling (CR) is a structural change of the heart due to chronic hemodynamic overload related to changes in both myocyte and extracellular matrix (ECM). We investigated that the imbalance of collagen V promotes cardiomyocyte apoptosis that contributes to heart failure and cell death. Aortic stenosis was induced surgically and male Wistar rats were randomized to 18 weeks (Sham 18?w, n?=?12; AoS 18?w, n?=?12) and severe of heart failure (Sham HF, n?=?12; AoS HF, n?=?12) groups. Functional and structural echocardiogram, immunohistochemistry for Ki-67, TUNEL assay and Immunofluorescence for collagen were performed. Our main results were: (1) Progressive reduction of cardiac functional capacity due to cardiac remodeling with decreased eject fraction in heart failure; (2) Imbalance of collagen deposition with increased, crowded and irregular collagen I in situ expression; (3) Dysregulation of dynamic control of collagen fibers with exposed epitopes of collagen V; (4) Additional apoptosis that are dependent to cardiac injury. The collagen V expression in cardiac remodeling is for the first time described and may be related to additional apoptosis and autoimmune response. Our findings suggest a critical role of collagen V in cardiac remodeling to modulate and promote heart failure and death.  相似文献   
145.
The aim of this systematic review was to evaluate the effects of mandibular advancement or setback surgery on the facial soft tissue assessed using three-dimensional images. An electronic search was performed in the MEDLINE, Cochrane Library, Scopus, Virtual Health Library (VHL), Web of Science, and OpenGrey databases. Inclusion criteria comprised studies that evaluated the soft tissues of adult patients before and after mandibular advancement or setback surgery using computed tomography or magnetic resonance imaging. The risk of bias was analyzed. A total of 3501 studies were retrieved. The titles and abstracts of 2071 studies were read and 2040 of them were excluded. Thirty-one articles were read in full and six fulfilled the eligibility criteria and were included. A meta-analysis was performed using three of these articles. The correlation was significant and strong in the chin area (r = 0.876 and r = 0.868) and moderate for the lower lip/lower incisor (r = 0.690). The ratio for lower lip/infradentale was 78% and for Pog′/Pog was 98%. Due to the limited number of articles included, there is weak evidence to infer that changes in the facial soft tissue due to mandibular advancement or setback are significant, but changes in the lower lip tend to be smaller than changes in the chin area.  相似文献   
146.
147.
Femoral non-unions are difficult to treat even for the experienced orthopaedic trauma surgeon. If the non-union follows failure of modern stable internal fixation, the complexity of the management is further increased. We report two cases of stiff hypertrophic femoral non-unions after failed locking plate fixation that were successfully treated with a new hexapod circular external fixator. In addition to providing the necessary stability for functional rehabilitation and union, the hexapod circular fixator software allows gradual correction of deformities in order to restore the normal mechanical alignment of the limb.  相似文献   
148.
Objective: Describe the use of assistive technology to enhance communication opportunities for older adults.

Methods: A systematic review was conducted in two databases, PubMed and Web of Science, by using two different searches in each. The search was limited to original articles, in English language, including people aged 60 years and older that used any type of assistive technology for communication. The articles found in the initial search were filtered by title, abstracts and the remaining articles were fully read.

Results: Eighteen studies were included in this review after the reading of full-texts. Most of the studies included apparently healthy participants with communication limitations due to aging related changes and the others included people with some pathology that prevent them from normal communication.

Conclusion: Four categories of assistive technology were identified: assistive technology for people with speech problems; robot or videoconferencing systems; Information and Communication Technologies and, other types of assistive technology for communication, such as hearing aids and scrapbooks. Assistive technology for communication of older adults is not only used by people with disabilities that prevent them from usual communication. They are mostly for older adults without a pathological communication problem.  相似文献   

149.
The aim of this work was to develop a new product, port wine “caviar,” consisting of products based on red and white port wines used in different concentrations. Sample R+ consisted of red port wine at a concentration of 90%, sample R- was red port at 75%, sample W+ was white port at 90%, and sample W- was white port at 75%, all (m/m). The use of two types of port is related to different colors and the two concentrations related to the intensity. The results from the sensory analysis showed that the red port “caviar” at 90% was the best among the products tested, either in the preference test or in the evaluation of the individual characteristics. Furthermore, the market study revealed that this product can be successfully commercialized, particularly for the gourmet kitchen, which is one the main usages identified by the respondents.  相似文献   
150.
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