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   247332篇
  免费   12626篇
  国内免费   461篇
耳鼻咽喉   3254篇
儿科学   7778篇
妇产科学   5069篇
基础医学   35219篇
口腔科学   6257篇
临床医学   19922篇
内科学   54495篇
皮肤病学   6685篇
神经病学   21951篇
特种医学   7414篇
外国民族医学   101篇
外科学   30988篇
综合类   1227篇
一般理论   68篇
预防医学   22165篇
眼科学   4808篇
药学   17244篇
中国医学   749篇
肿瘤学   15025篇
  2023年   1401篇
  2022年   1244篇
  2021年   4055篇
  2020年   2491篇
  2019年   4566篇
  2018年   8169篇
  2017年   5463篇
  2016年   5532篇
  2015年   6047篇
  2014年   6397篇
  2013年   10117篇
  2012年   16933篇
  2011年   17001篇
  2010年   8581篇
  2009年   6406篇
  2008年   14412篇
  2007年   15343篇
  2006年   14082篇
  2005年   13966篇
  2004年   13069篇
  2003年   11902篇
  2002年   11246篇
  2001年   6308篇
  2000年   6374篇
  1999年   5687篇
  1998年   995篇
  1997年   817篇
  1996年   767篇
  1992年   3241篇
  1991年   2915篇
  1990年   2778篇
  1989年   2539篇
  1988年   2416篇
  1987年   2250篇
  1986年   2145篇
  1985年   1925篇
  1984年   1443篇
  1983年   1216篇
  1982年   694篇
  1979年   1229篇
  1978年   867篇
  1977年   811篇
  1975年   814篇
  1974年   990篇
  1973年   1007篇
  1972年   946篇
  1971年   932篇
  1970年   867篇
  1969年   917篇
  1968年   795篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
The increased number of lymphocytes in airways during an asthmatic response is believed to be the result of increased recruitment of these cells. However, it is possible that a decreased apoptotic rate could also contribute to the increased number. The aim of the present study was to investigate whether allergen airway provocation influences the apoptotic phenotype of lung and peripheral blood lymphocytes (PBL) in subjects with atopic asthma. Bronchoalveolar lavage (BAL) lymphocytes and PBL from 12 asthmatic subjects previously challenged with allergen (n = 7) or saline (n = 5) were exposed to the apoptotic stimulus tributyltin (TBT) in vitro and assayed for apoptosis. Airway allergen provocation resulted in decreased sensitivity of BAL lymphocytes to TBT-induced apoptosis, with 42.2% (range 33.9-62.5%) apoptotic cells before challenge versus 23.5% (range 15.3-42.4%) after challenge, while PBL were unaffected. The increased apoptosis resistance correlated with higher numbers of Bcl-2-expressing lymphocytes. Interestingly, baseline caspase-3-like activity was significantly elevated in viable BAL lymphocytes compared with viable PBL, and was unaltered by allergen exposure. In conclusion, allergen inhalation renders bronchoalveolar lavage lymphocytes more resistant to apoptosis while peripheral blood lymphocytes were not influenced at all, indicating that the apoptotic phenotype of airway lymphocytes may play a role in asthmatic inflammation.  相似文献   
13.
    
  相似文献   
14.
15.
Volume and profile of alcohol consumption among students and classmates as predictors of aggression and victimization: a multilevel analysis among Swiss adolescents

Objective:  

To test the effects of the volume of alcohol consumption and drinking patterns on alcohol-related aggression and victimization, both at the individual and class levels.  相似文献   
16.
The new treatment strategy for Peritoneal Surface Malignancy combines a cytoreductive surgery and perioperative intraperitoneal chemotherapy. Cytoreduction removes all macroscopic tumor. Intraperitoneal chemotherapy avoids implantation of microscopic residual tumor cells on intra-abdominal surfaces when it is administered intraoperatively and/or early in the postoperative period. Delivering cytotoxic drugs directly into the peritoneal cavity maximizes dose intensity and minimizes systemic toxicity. Hyperthermia is selectively cytotoxic for malignant cells and potentiates the effect of chemotherapy. Implementation of this procedure makes the perioperative personnel to face a risk of exposure to cytotoxic agents. Furthermore, peritonectomies and electro-evaporation of tumor nodules are performed with high voltage electrocautery, generating a large amount of surgical smoke during several hours. Inhalation of these fumes may be also a risk for healthcare workers. In this article, we analyse in depth these new risks of the operating room personnel, we review the literature, and we give guidelines for secure performance of cytoreductive surgery and hyperthermic intraoperative intraperitoneal chemotherapy, as well as for early postoperative intraperitoneal chemotherapy administration. These new procedures are safe techniques for patients and healthcare workers provided adequate policies are adopted to avoid occupational exposure.  相似文献   
17.
The purpose of the present study was to examine the self-image of a group of young persons with cerebral palsy. The respondents (3 girls and 4 boys, ages 12 to 17 years) were interviewed and asked to complete a personality inventory. The results from the personality inventory revealed that the respondents viewed themselves in a very positive manner and rated markedly higher than norm groups. This positive view corresponded well with the findings of the interview. The following conclusions are made: Further studies on self-image and the psychosocial development of adolescents with disabilities should (a) focus on the social interaction outside their immediate families, and (b) continue to use and develop methods where these adolescents can give voice to their own experiences and opinions.  相似文献   
18.
Social phobia, fear of negative evaluation and harm avoidance.   总被引:1,自引:0,他引:1  
This naturalistic, prospective investigation examined the role of fear of negative evaluation and the personality trait of harm avoidance in the anxiety levels of treated social phobia patients. One hundred and fifty-seven patients with DSM-IV social phobia were assessed before starting treatment and were then followed for up to two years. As expected, greater fear of negative evaluation and higher scores of harm avoidance were associated with greater anxiety at the 6 month follow-up, and harm avoidance remained a significant predictor at 24 months. However, no evidence was found for an interaction between the personality and cognitive variables examined. The findings are discussed in terms of the relative independence of these factors, as well as their potential implications for the treatment of this disorder.  相似文献   
19.
20.
OBJECTIVES: To determine whether aromatase expression in the eutopic endometrium and adenomyotic foci is affected by previous use of oral contraceptives containing gestodene, and to determine whether changes in cyclooxygenase-2 (COX-2) expression occur in adenomyosis during the menstrual cycle. PATIENT AND METHODS: This was a retrospective cohort study carried out in paraffin-embedded endometrial tissue obtained from patients with a histological diagnosis of adenomyosis obtained during the proliferative (n = 25) and luteal (n = 10) phases of the menstrual cycle and following the use of continuous oral contraception with gestodene/ethinyl estradiol (n = 7). COX-2 and aromatase expression were measured in both eutopic endometrium and adenomyotic foci using immunohistochemical methods. RESULTS: Aromatase expression was detected in 80% of the endometrial slices by immunohistochemistry. In positive cases, aromatase was mainly detected in the stromal cells of the eutopic endometrium, whereas in the adenomyotic foci this expression was negative in the majority of the cases. Oral contraceptives containing gestodene, on the other hand, were effective in suppressing aromatase expression in both eutopic and ectopic endometrium. COX-2 expression was detected by immunohistochemistry in the glandular epithelium of both eutopic endometrium and adenomyotic foci and there were no significant changes in its intensity throughout the menstrual cycle. CONCLUSION: Aromatase expression in the eutopic endometrium and adenomyotic foci is suppressed by oral contraceptives containing gestodene. Increased aromatase activity may be responsible for the persistent COX-2 expression during the luteal phase.  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