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   3280280篇
  免费   236931篇
  国内免费   5771篇
耳鼻咽喉   47135篇
儿科学   104209篇
妇产科学   90920篇
基础医学   477599篇
口腔科学   93567篇
临床医学   292188篇
内科学   631197篇
皮肤病学   73543篇
神经病学   259562篇
特种医学   125194篇
外国民族医学   894篇
外科学   499234篇
综合类   71103篇
现状与发展   16篇
一般理论   1189篇
预防医学   247939篇
眼科学   77997篇
药学   246035篇
  13篇
中国医学   6805篇
肿瘤学   176643篇
  2018年   34481篇
  2017年   26350篇
  2016年   29478篇
  2015年   33129篇
  2014年   46746篇
  2013年   70808篇
  2012年   96090篇
  2011年   102250篇
  2010年   60922篇
  2009年   57934篇
  2008年   96739篇
  2007年   104017篇
  2006年   104864篇
  2005年   101902篇
  2004年   97900篇
  2003年   94639篇
  2002年   92077篇
  2001年   148902篇
  2000年   152790篇
  1999年   129000篇
  1998年   37134篇
  1997年   32789篇
  1996年   32450篇
  1995年   30775篇
  1994年   28470篇
  1993年   26828篇
  1992年   100507篇
  1991年   98088篇
  1990年   95954篇
  1989年   92904篇
  1988年   85921篇
  1987年   84504篇
  1986年   79857篇
  1985年   76596篇
  1984年   57040篇
  1983年   48635篇
  1982年   29103篇
  1981年   26252篇
  1979年   53442篇
  1978年   38300篇
  1977年   32491篇
  1976年   30466篇
  1975年   33620篇
  1974年   40138篇
  1973年   38531篇
  1972年   36487篇
  1971年   34434篇
  1970年   32152篇
  1969年   30728篇
  1968年   28418篇
排序方式: 共有10000条查询结果,搜索用时 781 毫秒
141.
142.
143.
144.
145.
146.
147.
148.
Porocarcinoma is an unusual, locally aggressive and potentially fatal neoplasm. Several cutaneous malignancies have been described in association with porocarcinoma, including squamous cell carcinoma, basal cell carcinoma and tricholemmal carcinoma. Previous reports have indicated that the occurrence of malignant tumours in combination with porocarcinoma is extremely rare, in particular with regard to Bowen disease (BD). We report an uncommon case of porocarcinoma occurring synchronously in a single BD lesion in a 63‐year‐old woman with multiple BD lesions. The clinical and histological findings confirmed this diagnosis.  相似文献   
149.
Children who expect they can bring about good outcomes and avoid bad outcomes tend to experience more personal successes. Little is known about factors that contribute to these ‘control expectancies’. The purpose of the present study was to determine whether children's internal control expectancies occur in the context of parents’ internal control expectancies, low family strain, and high family cohesiveness and whether these factors are more strongly related to daughters’ than sons’ control expectancies. A community sample of 85 children aged 9–11 years and their parents (85 mothers; 63 fathers) completed rating scales. Fathers’ more internal control expectancies and mothers’ reports of fewer family strains were associated with daughters’ but not sons’ greater internal control expectancies, and greater family cohesiveness was related to both daughters’ and sons’ internal control orientations. These findings suggest that family factors may contribute to children's, particularly daughters’, development of internal control expectancies.  相似文献   
150.
Objective: Polyunsaturated fatty acids n-3 (PUFA n-3) have shown effects in reducing tumor growth, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) abundantly present in fish oil (FO). When these fatty acids are provided in the diet, they alter the functions of the cells, particularly in tumor and immune cells. However, the effects of α-linolenic fatty acid (ALA), which is the precursor of EPA and DHA, are controversial. Thus, our objective was to test the effect of this parental fatty acid. Methods: Non-tumor-bearing and tumor-bearing Wistar rats (70 days) were supplemented with 1 g/kg body weight of FO or Oro Inca® (OI) oil (rich in ALA). Immune cells function, proliferation, cytokine production, and subpopulation profile were evaluated. Results: We have shown that innate immune cells enhanced phagocytosis capacity, and increased processing and elimination of antigens. Moreover, there was a decrease in production of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6)) by macrophages. Lymphocytes showed decreased proliferation capacity, increased cluster of differentiation 8 (CD8+) subpopulation, and increased TNF-α production. Conclusions: Oil rich in ALA caused similar immune modulation in cancer when compared with FO.  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