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   5740篇
  免费   533篇
  国内免费   51篇
耳鼻咽喉   94篇
儿科学   164篇
妇产科学   104篇
基础医学   760篇
口腔科学   519篇
临床医学   667篇
内科学   1147篇
皮肤病学   233篇
神经病学   435篇
特种医学   173篇
外科学   560篇
综合类   118篇
现状与发展   30篇
预防医学   534篇
眼科学   98篇
药学   401篇
中国医学   34篇
肿瘤学   253篇
  2024年   26篇
  2023年   246篇
  2022年   148篇
  2021年   269篇
  2020年   217篇
  2019年   219篇
  2018年   301篇
  2017年   195篇
  2016年   232篇
  2015年   261篇
  2014年   358篇
  2013年   327篇
  2012年   452篇
  2011年   511篇
  2010年   315篇
  2009年   275篇
  2008年   299篇
  2007年   350篇
  2006年   226篇
  2005年   191篇
  2004年   151篇
  2003年   105篇
  2002年   111篇
  2001年   20篇
  2000年   22篇
  1999年   31篇
  1998年   46篇
  1997年   53篇
  1996年   51篇
  1995年   39篇
  1994年   36篇
  1993年   38篇
  1992年   13篇
  1991年   8篇
  1990年   15篇
  1989年   23篇
  1988年   21篇
  1987年   14篇
  1986年   7篇
  1985年   12篇
  1984年   7篇
  1982年   9篇
  1981年   11篇
  1980年   14篇
  1979年   3篇
  1978年   5篇
  1977年   4篇
  1976年   13篇
  1975年   10篇
  1974年   4篇
排序方式: 共有6324条查询结果,搜索用时 31 毫秒
1.
2.
Prevention Science - This study aimed to evaluate the effectiveness of the drug and violence resistance educational program (PROERD) on short-term secondary outcomes, such as intentions to use...  相似文献   
3.
This study was designed to characterize a collection of 60 enteropathogenic Escherichia coli (EPEC) isolates from diarrheic feces of patients in the Ribeirão Preto metropolitan area regarding different phenotypic and molecular features. We examined antibiotic resistance profiles, occurrence of virulence factors‐encoding genes, intimin subtypes and the correlation of serotypes among typical (tEPEC) and atypical (aEPEC) EPEC isolates. The results demonstrated that atypical EPEC was more heterogeneous than typical EPEC concerning the characteristics investigated and 45.2% do not belong to classical EPEC serogroups. Intimin subtype β was the most frequent among the EPEC isolates (46.7%), being detected in both tEPEC and aEPEC. The majority of aEPEC isolates presented localized adherence‐like (LAL) pattern to HEp‐2 cells, although aEPEC isolates displaying diffuse adherence (DA) or non‐adherent were also detected. High prevalence of antimicrobial resistance was found for ampicillin, cephalothin, sulfonamide and tetracycline. In general, tEPEC isolates were more resistant to the antimicrobials tested than aEPEC isolates.  相似文献   
4.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  相似文献   
5.
Bacterial ghosts (BGs) are empty bacterial envelopes of Gram-negative bacteria produced by controlled expression of cloned gene E, forming a lysis tunnel structure within the envelope of the living bacteria. BGs are devoid of cytoplasmic content and possess all bacterial bio-adhesive surface properties in their original state while not posing any infectious threat. BGs are ideally suited as an advanced drug delivery system (ADDS) for toxic substances in tumor therapy. The inner space of BGs can be loaded with either single components or combinations of peptides, drugs or DNA which provides an opportunity to design new types of (polyvalent) drug delivery vehicles. Uptake of BGs loaded with Doxorubicin (Dox) by CaCo2 cells led to effective Dox release from endo-lysosomal compartments and accumulation in the nucleus. Viability and proliferative capacity of the cells were significantly decreased (2–3 orders of magnitude) after internalization of Dox loaded BGs as compared to cells incubated with free Dox. The same effect was observed with leukemia cells. Melanoma cells also revealed a high capability to internalize BGs. These results indicate that BGs are able to target a range of types of cancer. BGs have also been investigated as DNA delivery vectors. Studies show DNA loaded BGs are efficiently phagocytosed and internalized by both professional APCs and tumor cells with up to 82% of cells expressing the plasmid-encoded reporter gene. Our studies with BGs as an ADDS system contribute (i) to optimize drug delivery for the treatment of cancer; (ii) define specific conditions for selection and preparation of BG formulations; (iii) and provide a background for the clinical application of BGs in cancer therapy.  相似文献   
6.
7.
8.
Defecography in multiple sclerosis patients with severe constipation   总被引:3,自引:0,他引:3  
Gill  KP; Chia  YW; Henry  MM; Shorvon  PJ 《Radiology》1994,191(2):553
  相似文献   
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