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   8859篇
  免费   941篇
  国内免费   20篇
耳鼻咽喉   65篇
儿科学   193篇
妇产科学   240篇
基础医学   1547篇
口腔科学   178篇
临床医学   1183篇
内科学   1832篇
皮肤病学   78篇
神经病学   769篇
特种医学   235篇
外国民族医学   1篇
外科学   1160篇
综合类   141篇
一般理论   7篇
预防医学   941篇
眼科学   121篇
药学   432篇
中国医学   10篇
肿瘤学   687篇
  2022年   67篇
  2021年   154篇
  2020年   92篇
  2019年   144篇
  2018年   153篇
  2017年   134篇
  2016年   157篇
  2015年   171篇
  2014年   234篇
  2013年   355篇
  2012年   491篇
  2011年   505篇
  2010年   319篇
  2009年   278篇
  2008年   473篇
  2007年   486篇
  2006年   491篇
  2005年   417篇
  2004年   436篇
  2003年   458篇
  2002年   403篇
  2001年   185篇
  2000年   183篇
  1999年   169篇
  1998年   122篇
  1997年   98篇
  1996年   103篇
  1995年   74篇
  1994年   73篇
  1993年   70篇
  1992年   142篇
  1991年   150篇
  1990年   153篇
  1989年   124篇
  1988年   143篇
  1987年   111篇
  1986年   147篇
  1985年   125篇
  1984年   88篇
  1983年   97篇
  1982年   58篇
  1981年   62篇
  1979年   78篇
  1978年   59篇
  1977年   59篇
  1976年   58篇
  1974年   61篇
  1973年   69篇
  1971年   52篇
  1970年   55篇
排序方式: 共有9820条查询结果,搜索用时 15 毫秒
51.
52.
In a prospective cohort study of the long-term sequelae of induced abortion, a comparison is made between a group of 6418 women who had an induced abortion (cases) and a control group of 8059 women recruited with an unplanned pregnancy which was not terminated with an induced abortion (controls). The present paper reports on 729 cases and 1754 controls who had a post-recruitment pregnancy. In general, prior induced abortion had no material effect on the rate of pregnancy-related morbidity, nor on the rate of congenital abnormalities and neonatal death in the offspring. There was, however, a significant difference in two specific conditions. In the post-index pregnancy in the cases there was an increased relative risk (RR 2.26) of the occurrence of urinary tract infection and a decreased risk (RR 0.25) of pregnancy-related anaemia.  相似文献   
53.
R E O''Hehir  D B Young  A B Kay    J R Lamb 《Immunology》1987,62(4):635-640
In this report, T-cell and B-cell recognition of the house dust mite Dermatophagoides farinae (D. far.) is compared. Nitrocellulose immunoblots of polyacrylamide gel electrophoresis (SDS-PAGE)-fractionated D. far. were added to proliferation assays to map the antigen specificity of cloned human helper T cells and a long-term line induced with D. far. T-cell recognition was of a polypeptide of molecular weight 9000-13,000, that migrates with the serologically defined allergen Der fII (12,500 MW). Since the cloned T cells, unlike the polyclonal response, failed to respond to Dermatophagoides pteronyssinus (D. pter.), this suggests that they recognize a species-specific epitope. In contrast, analysis of the B-cell response using Western blotting demonstrated that, in addition to Der fII, antibodies reactive with the major allergens Der fI (26,000 MW) and Der fIII (29,000 MW) were present in the serum. Similar specificities were seen in the antibody response to D. pter., and while it has been reported that the B-cell response to D. far. and D. pter. are predominantly cross-reactive, our observations suggest that species-specific CD4-positive T cells are present in the overall cellular response to D. far.  相似文献   
54.
55.
The postoperative care of stoma patients is truly life long. With the excellent stoma equipment available, no patient should be a "stoma cripple." New advances in continent reservoirs will improve patient acceptance and lessen the fear associated with stomas. Finally, close follow-up by both the enterostomal therapy nurse and the surgeon is essential for the complete care of the stoma patient.  相似文献   
56.
57.
The term "health state utility" implies the assigning of a numerical value to a state of health. Assessment of the success of health care procedures, using health state utilities, enables evaluation of available treatments and procedures in terms of differing health outcomes and therefore facilitates cost-benefit analyses. Although measurement of general health state utilities has become increasingly common in medicine using a variety of techniques, few attempts have as yet been made in dentistry to place valuations on different dental health states. The absence of tried and tested methods for measuring tooth quality make the benefits gained from preventive and restorative dental programmes difficult to quantify. The aim of this study was to assess the average utility values, held by a group of dentists and a group of members of the general public, for four different tooth states which it was hypothesised would have different values. These were 1) a decayed and painful posterior tooth; 2) a decayed and non-painful posterior tooth; 3) a posterior tooth which had been restored and would need further restorative treatment and 4) a permanently restored posterior tooth. A standard gamble questionnaire was used to elicit the utility values which were then substituted as "weightings" in a modified version of the "T-health" index (1). The results show that it is possible to assess dental health state utility values using the standard gamble method and that the average utility values of the dentists in the study were consistently higher than those of the general public.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
58.
With the use of monoclonal antibodies (mAb) and immunohistology, the numbers of phenotypically distinct cells infiltrating lung tissue from 15 postmortem (PM) cases of fatal asthma were quantified and compared with 6 cases of cystic fibrosis (CF) (three postmortem, three transplant) and 10 nonasthmatic cases of sudden death matched for age and sex. Tissue eosinophilia was significantly greater (p less than 0.001) in the fatal asthma group than in the CF or sudden death controls. In asthma, approximately 40% of the eosinophilic infiltrate was EG2 positive (an indication of eosinophil activation and secretion of eosinophil cationic protein). The numbers of eosinophils and EG2 positive cells were significantly elevated in the subjects with acute severe asthma who had had a duration of terminal illness exceeding, as compared with less than, 24 h (p less than 0.05). When compared with the sudden death controls, there were increases in the numbers of Dako L C positive cells (i.e., CD45 positive "total leukocytes") in both fatal asthma and CF (p less than 0.01 and 0.05, respectively). The mean number of MT-1 positive (T) cells in the asthma and CF groups was approximately twice that of the control (p less than 0.05 and 0.01, respectively). The mean number of MB2 positive (B) cells was similar for both the asthma and sudden death control groups but was significantly increased in CF (p less than 0.05). The average T:B cell ratios were 6:1, 1:1, and 2:1 in the fatal asthma, CF, and control groups, respectively. The results support a role for the T lymphocyte in the pathogenesis of fatal asthma and CF.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
59.
60.
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