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   1064764篇
  免费   81308篇
  国内免费   7618篇
耳鼻咽喉   13357篇
儿科学   35160篇
妇产科学   29315篇
基础医学   153656篇
口腔科学   28859篇
临床医学   99369篇
内科学   203717篇
皮肤病学   23637篇
神经病学   82621篇
特种医学   40715篇
外国民族医学   346篇
外科学   156317篇
综合类   35573篇
现状与发展   17篇
一般理论   387篇
预防医学   81970篇
眼科学   24396篇
药学   79028篇
  77篇
中国医学   5694篇
肿瘤学   59479篇
  2021年   10408篇
  2019年   9625篇
  2018年   12895篇
  2017年   10248篇
  2016年   11372篇
  2015年   13658篇
  2014年   18288篇
  2013年   25179篇
  2012年   33640篇
  2011年   36374篇
  2010年   21705篇
  2009年   19859篇
  2008年   32104篇
  2007年   33851篇
  2006年   34459篇
  2005年   33007篇
  2004年   31092篇
  2003年   29936篇
  2002年   28591篇
  2001年   48454篇
  2000年   49667篇
  1999年   42129篇
  1998年   12398篇
  1997年   11414篇
  1996年   11152篇
  1995年   10652篇
  1994年   9852篇
  1993年   8965篇
  1992年   32806篇
  1991年   31952篇
  1990年   31435篇
  1989年   30247篇
  1988年   27472篇
  1987年   27577篇
  1986年   25655篇
  1985年   24753篇
  1984年   18494篇
  1983年   15579篇
  1982年   9319篇
  1979年   16893篇
  1978年   12217篇
  1977年   10314篇
  1976年   9754篇
  1975年   10178篇
  1974年   12317篇
  1973年   11843篇
  1972年   10884篇
  1971年   10113篇
  1970年   9375篇
  1969年   8724篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
The commodity model of social support and features of Nondirective Support may clarify varied results of support interventions for smoking cessation. A commodity model views social support as attractive in and of itself and as an alternative to high-risk choices such as smoking. If such support is easily accessible, a would-be quitter is less likely to choose to smoke. Consistent with the commodity model, social support interventions tend to be effective as long as support remains available, but they lose their effects when support is terminated. From a second approach, Nondirective Support entails accepting recipients' goals, cooperating without taking control, and validating recipients' feelings. In contrast, Directive Support entails taking control and telling recipients what to do and feel. Review of support interventions indicates the value of the continued availability of support suggested by the commodity model and of Nondirective Support's flexibility and responsiveness to the person.  相似文献   
92.
Background: The study reviews the anticancer properties of naturalisoflavones which occur in especially high concentration in soybeans. Itconsiders the suitability of soybean products for clinical trials aiming toreduce the progression of breast cancer.Methods: Evidence is reviewed that plant isoflavones such asgenistein show cytostatic activity against human mammary cancer cell linesin vitro and can also suppress carcinogen-induced mammary cancer inyoung and mature rats.Results: Plant isoflavones are converted in the bowel to compoundswith potential antioestrogenic and antioxidative properties. These compoundsshow cytostatic activity for both oestrogen receptor-positive and negativehuman mammary cancer cell lines, and also inhibit growth and progress of therat mammary cancer model. The high content of soybean products in the diet ofAsian women has been postulated as one reason for their relatively low breastcancer incidence.Conclusion: Preclinical studies suggest that soybean products begiven priority for clinical trials in breast cancer protection. A pilot studycould test soy protein supplements as long-term adjuvant dietary treatmentafter primary surgery for early breast cancer, looking for a decrease in therisk of recurrence or of second primary tumours.  相似文献   
93.
94.
The objectives of this study were to investigate (1) changes in consumption of alcohol among pregnant women over a period of 5 years (1984/85–1990), (2) changes of attitudes towards drinking during pregnancy in the general population over the same period of time, and (3) possible connections between (1) and (2). The investigation was designed as a cross-sectional study. Our subjects were two representative samples of pregnant women in Oslo, n = 577 and 425, and two representative samples of the Norwegian population, n = 1004 and 1204. The main outcome measures were a self-completed questionnaire for the pregnant women and a personal interview for the general population sample. There was a significant reduction (50% decrease) in alcohol consumption among the second cohort of pregnant women compared with the first. Furthermore, we found an increase during the 5-year period in the number of persons with a restrictive attitude towards alcohol use during pregnancy. There seems to be a connection between these two phenomena, but with our present state of knowledge it is hard to say anything about the causal relationship between them.  相似文献   
95.
Corpus cavernosography in a patient with erectile dysfunction revealed absence of communication between the 2 cavernous bodies. No similar case was found in a review of 100 consecutive cavernosograms or in the literature. The abnormality may be a source of error in pressure recordings or in intravenous injection of pharmaceutical agents.  相似文献   
96.
97.
98.
The urological complications of 320 consecutive renal transplants performed at our institution between October 17, 1985 and November 10, 1989 are reviewed. The Leadbetter-Politano technique of ureteroneocystostomy was used in the first 160 patients (group 1) and an anterior extravesical technique modified from the methods of Witzel, Sampson and Lich was performed in the second 160 patients (group 2). Urological complications occurred in 15 patients (9.4%) in group 1 and 6 (3.7%) in group 2 (p = 0.04). Ureterovesical junction obstruction occurred in 6 patients (3.7%) in group 1 and 1 (0.6%) in group 2 (p = 0.05). Complications of leakage, ureteral necrosis and ureteral stricture were comparable in the 2 groups. Therefore, we advocate the use of the anterior extravesical technique over Leadbetter-Politano ureteral reimplantation based on the lower incidence of urological complications and various technical advantages, including less operative time, avoidance of a separate cystotomy, less hematuria and ability to use short donor ureters.  相似文献   
99.
100.
Preservation of the breast with a good or excellent cosmetic appearance is achievable in most patients. Careful attention to the details of surgical technique allows these procedures to be carried out easily and comfortably for the patient and the surgeon alike.  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