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   29037篇
  免费   6330篇
  国内免费   177篇
耳鼻咽喉   718篇
儿科学   767篇
妇产科学   784篇
基础医学   1312篇
口腔科学   2871篇
临床医学   4664篇
内科学   7160篇
皮肤病学   596篇
神经病学   2419篇
特种医学   1300篇
外科学   5075篇
综合类   98篇
现状与发展   12篇
预防医学   2856篇
眼科学   588篇
药学   753篇
中国医学   24篇
肿瘤学   3547篇
  2024年   171篇
  2023年   1161篇
  2022年   472篇
  2021年   847篇
  2020年   1349篇
  2019年   636篇
  2018年   1505篇
  2017年   1434篇
  2016年   1658篇
  2015年   1749篇
  2014年   2166篇
  2013年   2627篇
  2012年   1203篇
  2011年   1180篇
  2010年   1628篇
  2009年   2196篇
  2008年   1185篇
  2007年   982篇
  2006年   1082篇
  2005年   871篇
  2004年   692篇
  2003年   657篇
  2002年   642篇
  2001年   642篇
  2000年   515篇
  1999年   582篇
  1998年   592篇
  1997年   550篇
  1996年   621篇
  1995年   457篇
  1994年   353篇
  1993年   294篇
  1992年   291篇
  1991年   258篇
  1990年   230篇
  1989年   232篇
  1988年   219篇
  1987年   209篇
  1986年   199篇
  1985年   164篇
  1984年   133篇
  1983年   128篇
  1982年   102篇
  1981年   85篇
  1980年   68篇
  1979年   66篇
  1978年   43篇
  1977年   58篇
  1975年   54篇
  1974年   49篇
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
1.
2.
3.

Purpose

Suppression of respiratory movement of the liver would be desirable for high-precision radiation therapy for liver tumors. We aimed to investigate the effect of our original device-free compressed shell fixation method and breathing instruction on suppression of respiratory movement. The characteristics of liver motion based on the movement of a fiducial marker were also analyzed.

Methods and Materials

First, respiratory amplitudes of the liver with the device-free compressed shell were analyzed from the data of 146 patients. The effect of this shell fixing method on liver movement was evaluated. Second, as another cohort study with 166 patients, interfractional internal motion of the liver for patients fixed in the shell was calculated using the fiducial marker coordinate data of images for position setting before daily irradiation. Third, in another 12 patients, intrafractional internal motion was calculated from the fiducial marker coordinate data using x-ray images before and after irradiation.

Results

The median respiratory movement without the shell, after fixing with the shell, and after instructing on the breathing method with the shell was 14.2 (interquartile range, 10.7-19.8), 11.5 (8.6-17.5), and 10.4 mm (7.3-15.8), respectively. Systematic and random errors of interfractional internal motion were all ≤2 mm in the left-right and anteroposterior directions and 3.7 and 3.0 mm, respectively, in the craniocaudal direction. Systematic and random errors of intrafractional internal motion were all ≤1.3 mm in the left-right and anteroposterior directions and 0.8 and 2.4 mm, respectively, in the craniocaudal direction.

Conclusions

The device-free compressed shell fixation method was effective in suppressing the respiratory movement of the liver. Irradiation position matching using the fiducial marker can correct the interfractional internal motion on each day, which would contribute to the reduction of the margin to be given around the target.  相似文献   
4.
The association between asbestos exposure, mainly in occupational settings, and malignant mesothelioma has been well established; this has prompted several countries to establish mesothelioma epidemiologic surveillance programs often at the request of national agencies. This review compares currently existing mesothelioma registries worldwide to develop a concept model for a US real-time case capture mesothelioma registry. Five countries were identified with a mesothelioma specific registry, including Italy, France, UK, Australia, and South Korea. All, except the UK, used interviews to collect exposure data. Linkage with the national death index was available or was in future plans for all registries. The registries have limited information on treatment, quality of life, and other patient-centered outcomes such as symptoms and pain management. To thoroughly collect exposure data, “real-time” enrollment is preferable; to maximize the capture of mesothelioma cases, optimal coverage, and a simplified consent process are needed.  相似文献   
5.
6.
Our aim was to evaluate the long-term skeletal stability of the mandible in 21 patients after orthognathic surgery with physiological positioning. The measurement points SNB, B point (X, Y), Pog (X, Y), and the angle of the ramus were measured on cephalometric photographs to assess skeletal stability preoperatively, immediately after operation, and one and two years postoperatively. In addition, we evaluated the clinical symptoms of disorders of the temporomandibular joint (TMJ). The analysis of the cephalometric photographs showed that SNB, B point X, and Pog X showed no significant differences among the postoperative time points. On the other hand, B point Y and Pog Y showed no significant differences throughout the study period. We compared the angle of the ramus before operation and two years postoperatively, and no significant difference was found. In addition, no cases showed any pathological symptoms of disorders of the TMJ two years postoperatively. The long-term stability after orthognathic surgery with physiological positioning was confirmed, and it seems to be a reliable orthognathic treatment in patients with mandibular prognathism.  相似文献   
7.
8.
9.
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