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   22492篇
  免费   1324篇
  国内免费   139篇
耳鼻咽喉   163篇
儿科学   371篇
妇产科学   212篇
基础医学   2712篇
口腔科学   533篇
临床医学   1441篇
内科学   5527篇
皮肤病学   1411篇
神经病学   1900篇
特种医学   977篇
外科学   3797篇
综合类   109篇
一般理论   1篇
预防医学   557篇
眼科学   212篇
药学   1843篇
中国医学   44篇
肿瘤学   2145篇
  2023年   162篇
  2022年   116篇
  2021年   630篇
  2020年   338篇
  2019年   454篇
  2018年   583篇
  2017年   490篇
  2016年   585篇
  2015年   568篇
  2014年   729篇
  2013年   767篇
  2012年   1276篇
  2011年   1312篇
  2010年   702篇
  2009年   577篇
  2008年   1084篇
  2007年   1180篇
  2006年   1083篇
  2005年   1033篇
  2004年   993篇
  2003年   911篇
  2002年   817篇
  2001年   607篇
  2000年   665篇
  1999年   631篇
  1998年   261篇
  1997年   174篇
  1996年   149篇
  1995年   151篇
  1994年   126篇
  1993年   111篇
  1992年   445篇
  1991年   395篇
  1990年   401篇
  1989年   423篇
  1988年   399篇
  1987年   368篇
  1986年   319篇
  1985年   287篇
  1984年   171篇
  1983年   152篇
  1982年   80篇
  1979年   164篇
  1978年   81篇
  1977年   84篇
  1974年   71篇
  1973年   83篇
  1972年   83篇
  1970年   74篇
  1969年   69篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
International Journal of Clinical Oncology - The practice of cancer diagnosis disclosure to children has been changed with the times. The regulations of clinical trials in the 2000s might change...  相似文献   
2.
3.
4.

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   
5.
6.
The accumulation of abnormal prion protein (PrPSc) produced by the structure conversion of PrP (PrPC) in the brain induces prion disease. Although the conversion process of the protein is still not fully elucidated, it has been known that the intramolecular chemical bridging in the most fragile pocket of PrP, known as the “hot spot,” stabilizes the structure of PrPC and inhibits the conversion process. Using our original structure-based drug discovery algorithm, we identified the low molecular weight compounds that predicted binding to the hot spot. NPR-130 and NPR-162 strongly bound to recombinant PrP in vitro, and fragment molecular orbital (FMO) analysis indicated that the high affinity of those candidates to the PrP is largely dependent on nonpolar interactions, such as van der Waals interactions. Those NPRs showed not only significant reduction of the PrPSc levels but also remarkable decrease of the number of aggresomes in persistently prion-infected cells. Intriguingly, treatment with those candidate compounds significantly prolonged the survival period of prion-infected mice and suppressed prion disease-specific pathological damage, such as vacuole degeneration, PrPSc accumulation, microgliosis, and astrogliosis in the brain, suggesting their possible clinical use. Our results indicate that in silico drug discovery using NUDE/DEGIMA may be widely useful to identify candidate compounds that effectively stabilize the protein.Electronic supplementary materialThe online version of this article (10.1007/s13311-020-00903-9) contains supplementary material, which is available to authorized users.  相似文献   
7.
8.
9.
Kohmoto  Tomohiro  Masuda  Kiyoshi  Shoda  Katsutoshi  Takahashi  Rizu  Ujiro  Sae  Tange  Shoichiro  Ichikawa  Daisuke  Otsuji  Eigo  Imoto  Issei 《Gastric cancer》2020,23(3):403-417
Gastric Cancer - We aimed to identify novel tumor-promoting drivers highly expressed in gastric cancer (GC) that contribute to worsened prognosis in affected patients. Genes whose expression was...  相似文献   
10.
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   
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