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   2275021篇
  免费   162792篇
  国内免费   5617篇
耳鼻咽喉   30464篇
儿科学   68294篇
妇产科学   59173篇
基础医学   330003篇
口腔科学   64561篇
临床医学   210236篇
内科学   444150篇
皮肤病学   46911篇
神经病学   186152篇
特种医学   84039篇
外国民族医学   511篇
外科学   334104篇
综合类   44548篇
现状与发展   2篇
一般理论   726篇
预防医学   180160篇
眼科学   50374篇
药学   171246篇
  9篇
中国医学   5446篇
肿瘤学   132321篇
  2021年   18002篇
  2019年   19207篇
  2018年   28956篇
  2017年   21396篇
  2016年   23086篇
  2015年   26321篇
  2014年   34532篇
  2013年   53148篇
  2012年   75874篇
  2011年   79346篇
  2010年   45146篇
  2009年   41049篇
  2008年   73374篇
  2007年   77474篇
  2006年   77275篇
  2005年   74696篇
  2004年   71346篇
  2003年   67725篇
  2002年   65517篇
  2001年   107950篇
  2000年   111471篇
  1999年   93457篇
  1998年   24058篇
  1997年   21570篇
  1996年   21356篇
  1995年   20124篇
  1994年   18732篇
  1993年   17421篇
  1992年   72455篇
  1991年   70248篇
  1990年   67994篇
  1989年   65364篇
  1988年   60239篇
  1987年   58600篇
  1986年   55349篇
  1985年   52898篇
  1984年   38907篇
  1983年   33052篇
  1982年   18647篇
  1979年   35058篇
  1978年   24249篇
  1977年   20335篇
  1976年   18939篇
  1975年   20064篇
  1974年   24488篇
  1973年   23587篇
  1972年   22094篇
  1971年   20877篇
  1970年   19536篇
  1969年   18128篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
121.
122.
123.
124.
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   
125.
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   
126.
Reactive lymphoid infiltrates of the skin composed predominantly of gamma‐delta (γδ) T cells are not well described in the literature. Herein we report a case of an otherwise healthy 4‐year‐old male who presented with a waxing and waning papular rash characterized by small, discrete crusted papules spread across his trunk, face and extremities. Clinical evaluation revealed no evidence of systemic disease. Microscopic examination revealed a dermal, perivascular infiltrate of highly atypical lymphocytes with a γδ T cell phenotype, worrisome for primary cutaneous γδ T cell lymphoma. The clinical course, however, was that of a reactive condition and prompted consideration of a diagnosis of pityriasis lichenoides et varioliformis acuta (PLEVA) and lymphomatoid papulosis (LyP). In many ways, this case defies current classification schemes and seems to expand the spectrum of reactive γδ T cell infiltrates of the skin.  相似文献   
127.
128.
129.
130.
Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates.  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