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   1607篇
  免费   150篇
  国内免费   17篇
耳鼻咽喉   24篇
儿科学   75篇
妇产科学   63篇
基础医学   286篇
口腔科学   23篇
临床医学   134篇
内科学   264篇
皮肤病学   26篇
神经病学   37篇
特种医学   178篇
外科学   147篇
综合类   123篇
一般理论   7篇
预防医学   139篇
眼科学   39篇
药学   85篇
中国医学   2篇
肿瘤学   122篇
  2021年   19篇
  2020年   15篇
  2019年   18篇
  2018年   24篇
  2017年   20篇
  2016年   25篇
  2015年   39篇
  2014年   45篇
  2013年   47篇
  2012年   66篇
  2011年   57篇
  2010年   62篇
  2009年   49篇
  2008年   59篇
  2007年   59篇
  2006年   60篇
  2005年   49篇
  2004年   43篇
  2003年   44篇
  2002年   46篇
  2001年   41篇
  2000年   35篇
  1999年   43篇
  1998年   60篇
  1997年   51篇
  1996年   42篇
  1995年   35篇
  1994年   35篇
  1993年   29篇
  1992年   22篇
  1991年   29篇
  1990年   18篇
  1989年   35篇
  1988年   31篇
  1987年   52篇
  1986年   30篇
  1985年   29篇
  1984年   20篇
  1983年   13篇
  1982年   22篇
  1981年   17篇
  1979年   13篇
  1978年   19篇
  1977年   12篇
  1976年   17篇
  1975年   13篇
  1969年   10篇
  1968年   11篇
  1967年   11篇
  1966年   16篇
排序方式: 共有1774条查询结果,搜索用时 15 毫秒
1.
Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography‐guided fine‐needle aspiration biopsy (EUS‐FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS‐FNAB was performed was 62 years (range 26–82 years) and the median follow‐up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS‐FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed.  相似文献   
2.
Coronary artery bypass grafts: visualization with MR imaging   总被引:1,自引:0,他引:1  
Gomes  AS; Lois  JF; Drinkwater  DC  Jr; Corday  SR 《Radiology》1987,162(1):175
  相似文献   
3.
4.
5.
6.
The normal leakage flow in modern technical heart valve prostheses can be visualized by color-coded Doppler-echocardiography, provided that an adequate ultrasonic image quality can be achieved. Sometimes it may be difficult, however, to distinguish such a normal leakage flow from pathological regurgitation. We therefore mounted new specimens of five different types of prostheses (Bj?rk-Shiley monostrut, Medtronic-Hall, Omnicarbon, Saint Jude Medical, Duromedics) into an invitro model, where the leakage flows could directly be visualized as emerging water jets. When the system was completely filled, the jets could also be registered by two-dimensional Doppler-echocardiography. For each valve, characteristic patterns for the localization of the principal jets were found. Besides the relative broad central jet in the Medtronic-Hall valve, all other jets arose mainly at the ring. They were detected at the hinges or the basis of the larger struts, respectively, and with asymmetrical mono-disc valves at the side of the smaller opening. The length and the orientation of the jets were found to change significantly with minimal variations of the position of the closing discs. This variability could be confirmed, when in a separate model the overall leakage flows were repeatedly measured. For patient examinations it seems useful to refer mainly to the localization of the jet origins. The comparison with reference values of jet-dimensions in Doppler images will rarely enable the examiner to distinguish between normal and pathological jets.  相似文献   
7.
When medical students become involved in patient care, concerns are raised that have ethical and possibly legal implications. In order to determine compliance with the guidelines of the U.S. government and the Joint Committee on Accreditation of Hospitals pertaining to informed consent, the authors conducted a study of hospital administrators, medical school department chairpersons, and medical school deans (with response rates ranging from 82.3 to 95.1 percent) concerning policies on student involvement in patient care. The results show that only 37.5 percent of all responding teaching hospitals specifically informed patients that students would be involved in care. Only 51 percent of the responding medical schools that specifically gave their students instruction or guidance on initial patient interaction as a matter of policy insisted that their students introduce themselves as students and clarify their role in patient care. The authors conclude that medical educators' compliance with the ethical requirements of informed consent is incomplete.  相似文献   
8.
The employment state of men living in the homes of children at the time that child abuse was diagnosed was determined. The series included a wide range of abuse, including non-accidental injury, failure to thrive, neglect, and emotional deprivation. Two cohorts of children seen during 1974-9 and 1980-5 were compared; these periods were chosen because a large increase in unemployment began in Sheffield in 1980. Although the proportion of the men without work was significantly increased during the second period, this increase could not be ascribed to the rise in either long term or short term unemployment among those who had previously been in regular employment. It was accounted for by a rise in the proportions of single parent families and families in which the resident man had never had regular employment. This may reflect an increase in pregnancies among young mothers. There was no evidence to support the belief that the loss of a job in otherwise stable families leads to an increase in child abuse.  相似文献   
9.
10.
W R Bezwoda  J D Esser  R Dansey  I Kessel  M Lange 《Cancer》1991,68(4):867-872
Four hundred fifteen patients with metastatic breast cancer with known hormone receptor status received primary treatment with tamoxifen. Measured values for the estrogen receptor (ER, i.e., with estrogen binding) followed a continuous distribution (range, 3 to 1000 fmol/mg of protein). These values correlated positively with age. The response to treatment with tamoxifen correlated with the ER level, with response rates of approximately 80% when the ER level was greater than 30.1 fmol/mg of protein. Two hundred eighteen (218 of 415, 52%) patients had progesterone receptor (PR) values greater than 10 fmol/mg. The PR positivity correlated with the ER level. Patients with PR levels greater than 10 fmol/mg of protein (124 of 226, 55%) had a significantly higher response rate than those with values less than 10 fmol/mg of protein (45 of 189, 24%). However, in a multivariate analysis including both receptor levels, age, site, and number of metastases, only the ER level was significant in predicting the response to treatment with tamoxifen. A quantitative estimation of the ER level thus is the best predictor of response to hormonal treatment with tamoxifen for advanced breast cancer.  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