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   2489篇
  免费   192篇
  国内免费   8篇
耳鼻咽喉   31篇
儿科学   181篇
妇产科学   53篇
基础医学   261篇
口腔科学   38篇
临床医学   226篇
内科学   626篇
皮肤病学   75篇
神经病学   128篇
特种医学   86篇
外国民族医学   1篇
外科学   352篇
综合类   73篇
一般理论   1篇
预防医学   185篇
眼科学   52篇
药学   173篇
中国医学   6篇
肿瘤学   141篇
  2023年   29篇
  2022年   23篇
  2021年   149篇
  2020年   69篇
  2019年   87篇
  2018年   92篇
  2017年   77篇
  2016年   66篇
  2015年   76篇
  2014年   100篇
  2013年   147篇
  2012年   165篇
  2011年   152篇
  2010年   84篇
  2009年   78篇
  2008年   93篇
  2007年   117篇
  2006年   136篇
  2005年   127篇
  2004年   112篇
  2003年   112篇
  2002年   113篇
  2001年   60篇
  2000年   44篇
  1999年   36篇
  1998年   13篇
  1997年   13篇
  1996年   14篇
  1995年   17篇
  1994年   9篇
  1993年   12篇
  1992年   17篇
  1991年   17篇
  1990年   14篇
  1989年   15篇
  1988年   20篇
  1987年   11篇
  1986年   16篇
  1985年   15篇
  1984年   18篇
  1983年   12篇
  1982年   7篇
  1979年   8篇
  1978年   9篇
  1976年   10篇
  1975年   7篇
  1973年   13篇
  1971年   6篇
  1970年   6篇
  1967年   6篇
排序方式: 共有2689条查询结果,搜索用时 281 毫秒
1.
PurposeTwitter is an increasingly popular social media platform within the health care community. The objective of this analysis is to characterize the profile of radiation oncology–related tweets and Twitter users over the past 6 years.Methods and MaterialsUsing the web-based social media analytics platform Symplur Signals, we filtered tweets containing at least 1 of the following hashtags or key words: #radonc, #radiationoncology, "rad onc," or "radiation oncology." We evaluated radiation oncology–related Twitter activity between October 2014 and March 2020 for tweet frequency, tweet content, and individuals or groups posting tweets. We identified the most influential Twitter users contributing to radiation oncology–related tweets.ResultsFrom 2014 to 2020, the quarterly volume of radiation oncology–related tweets increased from 5027 to 29,763. Physicians contributed the largest growth in tweet volume. Academic radiation oncologists comprise 60% of the most influential Twitter accounts responsible for radiation oncology–related content. The number of radiation-oncology resident physicians on Twitter increased from 25 to 328 over the past 6 years, and 20% of radiation-oncology residency programs have a Twitter account. Seventy-one percent of radiation oncology–related tweets generated direct communication via mentions, and 59% of tweets contain links to external sources, including scientific articles.ConclusionsThe number of physicians contributing radiation oncology–related Twitter content has increased significantly in recent years. Academic radiation oncologists are the primary influencers of radiation oncology–related Twitter activity. Twitter is used by radiation oncologists to both professionally network and discuss findings related to the field. There remains the opportunity for radiation oncologists to broaden their audience on Twitter to encompass a more diverse community, including patients.  相似文献   
2.
3.
This communication highlights scleral dellen as an unusual complication of strabismus surgery in a 55-year-old hypertensive male. The clinical significance, differential diagnosis and management of this condition has been discussed.  相似文献   
4.
5.
6.
Hazards of smoking   总被引:1,自引:0,他引:1  
A strong association exists between cigarette smoking and several diseases namely, cancer of the lung, bronchitis and emphysema, cancer of the larynx, oral cavity and oesophagus, gastric and duodenal ulcers, Crohn's disease, cancer of the bladder, coronary artery disease, macrocytosis, polycythaemia, leukaemia, etc. This is due to the harmful constituents of cigarette and other modalities smoking. Smokers not only harm themselves but also harm those around. Foetal malformations, abortions, stillbirths, prematurity and low birth weight are common in smoker mothers. These are the effects of passive smoking. There is no safer cigarette in the market even by lowering its harmful constituents. Mass education about the hazards of smoking with emphasis on complete stoppage of smoking is the only way to prevent its rising incidence.  相似文献   
7.
8.
A new method for the selective spin labeling of left- or right-sided supplying arteries of the brain without the need for additional RF coils is demonstrated. A clinical 1.5 T scanner was used. The spatial selectivity of the labeling process is based on the limited coverage of the excitation field of a standard send/receive head coil together with an oblique positioning of the labeling plane. A computer simulation was used to optimize key labeling parameters under the condition of laminar flow. The validity of the computer model results was confirmed by MRI measurements with a flow model. For human studies, a double-inversion continuous arterial spin labeling (CASL) sequence was modified to allow for arbitrary positioning of the labeling plane. The obtained perfusion-weighted images showed a clear delineation of the perfusion territories of the selected arteries in the anterior circulation of the brain and good gray/white matter contrast.  相似文献   
9.
An unusual retinal manifestation of arteriovenous communications is reported in a case showing a combination of Sturge-Weber and Kippel-Trenaunay syndromes. The arteriovenous communications are thought to be similar to those seen in the limbs in Parkes-Weber syndrome. This retinal finding indicates that the three syndromes are intricately related to each other and may be an incomplete manifestation of a single pathophysiologic entity which may be named neurocutaneous angiomatosis.  相似文献   
10.
In order to achieve a desired temperature distribution inside and outside of malignant tissues, optimization techniques could be used in phased array hyperthermia systems to control effectively the amplitude and phase of the radiating elements. The optimization of a four-element phased array hyperthermia system operating at 432 MHz is examined theoretically. The proposed technique is based on a detailed physical model of the tissue medium to be heated in terms of both electromagnetic and thermal properties. A penalty function technique using a Newton method is applied to determine the optimum phases and amplitudes of the array. Several array geometries have been studied and numerical results are presented.  相似文献   
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