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   3939篇
  免费   243篇
  国内免费   75篇
耳鼻咽喉   25篇
儿科学   144篇
妇产科学   92篇
基础医学   380篇
口腔科学   88篇
临床医学   341篇
内科学   908篇
皮肤病学   97篇
神经病学   146篇
特种医学   406篇
外科学   570篇
综合类   89篇
一般理论   1篇
预防医学   335篇
眼科学   62篇
药学   250篇
中国医学   9篇
肿瘤学   314篇
  2023年   26篇
  2022年   54篇
  2021年   133篇
  2020年   72篇
  2019年   87篇
  2018年   130篇
  2017年   125篇
  2016年   119篇
  2015年   102篇
  2014年   124篇
  2013年   186篇
  2012年   195篇
  2011年   213篇
  2010年   152篇
  2009年   116篇
  2008年   153篇
  2007年   186篇
  2006年   181篇
  2005年   189篇
  2004年   134篇
  2003年   118篇
  2002年   120篇
  2001年   57篇
  2000年   59篇
  1999年   63篇
  1998年   79篇
  1997年   63篇
  1996年   67篇
  1995年   52篇
  1994年   52篇
  1993年   48篇
  1992年   51篇
  1991年   68篇
  1990年   47篇
  1989年   52篇
  1988年   84篇
  1987年   55篇
  1986年   48篇
  1985年   62篇
  1984年   34篇
  1983年   20篇
  1982年   24篇
  1981年   21篇
  1980年   21篇
  1979年   22篇
  1978年   25篇
  1977年   19篇
  1976年   21篇
  1974年   18篇
  1973年   15篇
排序方式: 共有4257条查询结果,搜索用时 31 毫秒
1.
2.
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   
3.
Psychoactive medication use in intermediate-care facility residents   总被引:2,自引:0,他引:2  
M Beers  J Avorn  S B Soumerai  D E Everitt  D S Sherman  S Salem 《JAMA》1988,260(20):3016-3020
  相似文献   
4.
A thirty six week gestation male baby weighing three kilogram was born to a twenty five year old mother by spontaneous vaginal delivery. At four hours of life, the baby developed respiratory distress with cyanosis and was admitted to the neonatal intensive care unit. There was clinical and radiological evidence of bilateral pleural effusion. Thoracentesis revealed a transudate. Repeated thoracentesis was necessary to relieve the respiratory distress. Subsequently, multi resistant Klebsiella aerogenes was isolated from the blood. The baby expired due to gram negative sepsis.  相似文献   
5.
Cancer mortality in the elderly has rarely been analyzed. It is most notably characterized by the level of diagnostic accuracy at ages prone to comorbidities. Trend analysis over the last thirty years and disparities in mortality have underscored the increasing cancer mortality in the over-65 age bracket as well as the relevance of local health context in understanding the significant differences seen throughout France.  相似文献   
6.
BACKGROUND: Vitiligo is the most common pigmentary disorder with a global incidence from 0.1% to 2% in different geographical areas. Histopathology and histochemistry have shown the reduction of melanocytes in achromic patches, but microscopic changes of lesional and non-lesional skin are still not completely understood. Reflectance confocal microscopy (RCM), based on the different light reflectance index of cutaneous structures, allowed in vivo, en face microscopic evaluation of superficial skin layers with a resolution similar to skin histology. AIM: The purpose of this study was to evaluate RCM features of lesional and non-lesional skin of vitiligo patients. Moreover, re-pigmented areas were taken into consideration in order to evaluate melanocyte response to ultraviolet B (UVB) radiation. SUBJECTS AND METHODS: Sixteen patients of different phototypes affected by active non-segmental vitiligo and 10 controls were enrolled in the study. In vivo skin imaging was done using a commercially available RCM (Lucid, Vivascope 1500. Re-pigmented areas from 6 to 16 patients (after UVB narrow-band therapy) were also examined. RESULTS: Vitiligo lesions showed the disappearance of the bright rings normally seen at the dermo-epidermal junction. Moreover, non-lesional skin of vitiligo patients showed unexpected changes as the presence of half-rings or scalloped border-like features of the bright papillary rings. In re-pigmented areas after UVB narrow band therapy, the presence of activated, dendritic melanocytes was seen. CONCLUSIONS: Considering our results, and following further studies, RCM clinical applications could be used in the therapeutic monitoring and evaluation of the evolution of vitiligo.  相似文献   
7.
8.
9.
A procedure for the determination of methotrexate in human plasma is reported. The analysis involved extraction of methotrexate as an ion pair in ethyl acetate. Reconstituted residue was analyzed using reverse phase C-18 column and a mobile phase consisting of acetate buffer (87%), methanol (6.5%), and acetonitrile (6.5%). The methotrexate recovery range was 95-97%. Theophylline was used as internal standard with a recovery of 96%. The intraday coefficient of variation for the assay ranged from 1.8-3.0%, while interday variation coefficient range was 3.5-3.7%. The method is selective, reproducible, and covers a wide range of methotrexate concentrations in patient's plasma.  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