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   3490605篇
  免费   281837篇
  国内免费   14593篇
耳鼻咽喉   48477篇
儿科学   106963篇
妇产科学   91333篇
基础医学   547205篇
口腔科学   96915篇
临床医学   308498篇
内科学   618532篇
皮肤病学   93076篇
神经病学   298112篇
特种医学   138912篇
外国民族医学   453篇
外科学   543499篇
综合类   107105篇
现状与发展   24篇
一般理论   2262篇
预防医学   284443篇
眼科学   79683篇
药学   243063篇
  23篇
中国医学   10347篇
肿瘤学   168110篇
  2021年   54921篇
  2020年   35044篇
  2019年   58029篇
  2018年   70845篇
  2017年   54090篇
  2016年   59848篇
  2015年   73989篇
  2014年   108180篇
  2013年   173367篇
  2012年   90135篇
  2011年   89210篇
  2010年   115526篇
  2009年   120741篇
  2008年   77137篇
  2007年   80683篇
  2006年   91543篇
  2005年   86847篇
  2004年   89086篇
  2003年   80448篇
  2002年   70755篇
  2001年   109317篇
  2000年   102438篇
  1999年   101364篇
  1998年   65239篇
  1997年   63137篇
  1996年   60654篇
  1995年   56102篇
  1994年   50330篇
  1993年   47025篇
  1992年   71749篇
  1991年   68054篇
  1990年   65032篇
  1989年   64385篇
  1988年   60255篇
  1987年   58880篇
  1986年   56363篇
  1985年   56010篇
  1984年   50512篇
  1983年   45783篇
  1982年   42330篇
  1981年   39797篇
  1980年   37637篇
  1979年   42956篇
  1978年   37366篇
  1977年   34288篇
  1976年   31042篇
  1975年   30705篇
  1974年   32426篇
  1973年   31092篇
  1972年   29526篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
The incidence of uterine cervical cancer has increased slightly in Western countries, with an increase in relatively young women. Overexpression of matrix metalloproteinases (MMPs)-2 and -9 has turned out as a prognostic factor in many cancers. We compared the expression of the proteins MMP-2 and MMP-9 in cervical primary tumors with clinical outcome and risk factors of cervical cancer. One hundred sixty-one patients with cervical cancer treated in Ume? University Hospital or Sahlgrenska University Hospital, Sweden, between 1991 and 1995 were included in the study. Paraffin-embedded tissue samples obtained prior to treatment were examined immunohistochemically by specific antibodies for MMP-2 and MMP-9. Forty-two percent of the tumors were intensively positive for MMP-2 and 31% for MMP-9. Nineteen percent of the samples were intensively positive for both proteinases and 47% negative or weak for both. Overexpression of MMP-2 seemed to predict unfavorable survival under Kaplan-Meier analysis and in the multivariate analysis. Early sexual activity and low parity seemed to correlate to overexpression of MMP-2. MMP-9 was not associated with survival or sexual behavior. Intensive MMP-9 was noted in grade 1 tumors. We conclude that MMP-2 and MMP-9 have different roles in uterine cervical cancer. MMP-2 could be associated with aggressive behavior, but MMP-9 expression diminishes in high-grade tumors.  相似文献   
982.
The purpose of this study was to predict lymphatic involvement in endometrial cancer using clinicopathologic variables of patients treated with surgical staging. Overall, 461 patients treated with an initial surgical staging procedure including complete pelvic-para-aortic lymphadenectomy were included. The mean number of resected lymph nodes was 27 (median 26; range 15-83), and 54 patients (12%) had lymphatic involvement. Of these patients, 32 had only pelvic, 15 had both pelvic and para-aortic, and 7 had isolated para-aortic metastases. In the multivariate analysis, deep myometrial invasion (P= 0.02), lymphvascular space invasion (P= 0.001), positive peritoneal cytology (P= 0.002), and cervical involvement (P= 0.003) predicted retroperitoneal lymph node metastasis (RLN) significantly. Two hundred seventy-four patients (59.4%) had at least one of these poor prognostic factors identified by multivariate analysis. In this patient population, 53 (19.3%) had lymphatic involvement compared to 1 patient in the group of 187 patients with low-risk criteria. Ninety-eight percent of patients with RLN were predicted by this model, and with the advent of accurate diagnostic techniques, 40% of patients could be saved from undergoing lymphadenectomy.  相似文献   
983.
984.
985.
In a retrospective study using univariate analysis, we identified tumor type (nonendometrioid vs endometrioid), depth of myoinvasion (MI), mode of MI (infiltrative vs cohesive), and direct anatomic invasion of the cervical wall from the isthmus as significant positive risk factors for intramyometrial lymphvascular space involvement (LVSI). On multivariate analysis, tumor grade, depth of MI, and mode of MI retained their significance. We created a grid for the relative risks of LVSI with respect to these variables individually or in combination. We suggest that our indirect estimate of the risk of LVSI can help in assessing prognosis and determining the need for adjuvant therapy whenever LVSI is important in clinical decision making, but its pathologic diagnosis is uncertain.  相似文献   
986.
987.
The main objectives of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) are to harmonise breakpoints for antimicrobial agents in Europe, and to act as the breakpoint committee for the European Medicines Agency (EMEA) during the registration of new antimicrobial agents. Detailed EUCAST procedures for harmonising and setting breakpoints for antimicrobial agents are available on the EUCAST website. Beginning with the current issue, a series of EUCAST Technical Notes will be published in CMI, based on the rationale documents produced by EUCAST for each of the antimicrobial agents studied, with the aim of highlighting important background information underlying decisions on breakpoints made by EUCAST.  相似文献   
988.
989.
990.
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