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   16182篇
  免费   803篇
  国内免费   89篇
耳鼻咽喉   110篇
儿科学   191篇
妇产科学   178篇
基础医学   1963篇
口腔科学   406篇
临床医学   1043篇
内科学   3667篇
皮肤病学   1096篇
神经病学   1606篇
特种医学   633篇
外科学   2672篇
综合类   97篇
预防医学   422篇
眼科学   129篇
药学   1504篇
中国医学   35篇
肿瘤学   1322篇
  2023年   86篇
  2022年   164篇
  2021年   296篇
  2020年   163篇
  2019年   224篇
  2018年   294篇
  2017年   207篇
  2016年   294篇
  2015年   300篇
  2014年   370篇
  2013年   412篇
  2012年   656篇
  2011年   684篇
  2010年   381篇
  2009年   315篇
  2008年   667篇
  2007年   705篇
  2006年   652篇
  2005年   654篇
  2004年   672篇
  2003年   667篇
  2002年   639篇
  2001年   594篇
  2000年   668篇
  1999年   622篇
  1998年   248篇
  1997年   158篇
  1996年   160篇
  1995年   150篇
  1994年   118篇
  1993年   103篇
  1992年   441篇
  1991年   392篇
  1990年   408篇
  1989年   424篇
  1988年   400篇
  1987年   370篇
  1986年   322篇
  1985年   288篇
  1984年   172篇
  1983年   154篇
  1982年   80篇
  1979年   166篇
  1978年   82篇
  1977年   90篇
  1974年   74篇
  1973年   80篇
  1972年   88篇
  1970年   77篇
  1969年   74篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.

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   
2.
3.
4.
5.
neurogenetics - Mediator (MED) is a key regulator of protein-coding gene expression, and mutations in MED subunits are associated with a broad spectrum of diseases. Because mutations in MED17...  相似文献   
6.
We report a 53-year-old woman with severe Graves' ophthalmopathy accompanied by uncontrolled myasthenia gravis. She presented remarkable exophthalmos, chemosis, and restriction of eye movement. Despite plasma exchange, steroid pulse therapy, local injection of steroid, and irradiation, ocular symptoms did not ameliorate. Since optic neuropathy was seen, orbital decompression surgery was performed in the left eye. Bilateral chemosis was improved after the surgery. Five years after surgery, there was no ocular palsy in the operated left eye, but in the contralateral eye. For the good prognosis of the eye movement, orbital decompression might be recommended in the severe Graves' ophthalmopathy accompanied by the optic neuropathy and/or ophthalmoplegia with proptosis.  相似文献   
7.
Objective: Impacts of mediastinal lymph node dissection on a patient’s course after pulmonary resection is unclear in octogenarians with non-small cell lung cancer. Methods: Retrospectively identified subjects included 39 octogenarians and 1 nonagenarian, with grades according to the Charlson Comorbidity Index ranging from only 0 to 2. We performed mediastinal lymph node dissection in 19 patients (D group), and just lymph node sampling biopsy in the other 21 (S group). We compared clinicopathologic features and outcome after surgery between both groups. Results: Deterioration of performance status at the time of discharge, evident in 17 patients overall, was significantly more frequent in the D group. Postoperative complications occurred in 27 patients overall and there was no significant difference between the two groups. Survival rates in younger patients at 1, 3, and 5 years were 86, 59, and 49%, respectively; in octogenarians these were 83, 58, and 42% (no significant difference). Nor did survival differ significantly by surgical management of mediastinal lymph nodes; 1-, 3-, and 5-year survival rates were 94, 63, and 40%, respectively in the D group and 78, 66, and 43%, respectively in the S group. Conclusion: Octogenarians with non-small cell lung cancer should be treated by urgent pulmonary resection whenever possible. Since mediastinal lymph node dissection has little effect on long-term survival or the carried risk of worsening performance status at discharge, pulmonary resection without complete mediastinal lymph node dissection should be considered.  相似文献   
8.
9.
A nationwide survey of transient hyperammonemia in newborns was carried out in Japan. A total of 18 patients, consisting of 12 male and 6 female infants, were reported from 11 facilities. These neonates exhibited hyperammonemia with plasma ammonia levels in the range from 124 to 6256 micrograms/dl. Four newborn infants of the 18 died in the neonatal period, and an additional one died in the early infancy. Among the 13 infants who were alive at the time of this survey, 6 had neurological sequelae, including mental retardation, spastic quadriplegia and epilepsy. The multivariate analysis revealed that the Apgar score at 1 minute, peak plasma ammonia concentration, birth weight and sex were significant factors affecting the prognosis of life.  相似文献   
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