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   900760篇
  免费   62334篇
  国内免费   2338篇
耳鼻咽喉   12483篇
儿科学   28701篇
妇产科学   26190篇
基础医学   126710篇
口腔科学   24711篇
临床医学   74799篇
内科学   183430篇
皮肤病学   19012篇
神经病学   71459篇
特种医学   36491篇
外国民族医学   336篇
外科学   142268篇
综合类   19031篇
一般理论   247篇
预防医学   64609篇
眼科学   20101篇
药学   63868篇
中国医学   1801篇
肿瘤学   49185篇
  2018年   9100篇
  2017年   7203篇
  2016年   7719篇
  2015年   8757篇
  2014年   12403篇
  2013年   19284篇
  2012年   25705篇
  2011年   27298篇
  2010年   16608篇
  2009年   15814篇
  2008年   26166篇
  2007年   27772篇
  2006年   27942篇
  2005年   27486篇
  2004年   26333篇
  2003年   25488篇
  2002年   25078篇
  2001年   41375篇
  2000年   42567篇
  1999年   36287篇
  1998年   9973篇
  1997年   9150篇
  1996年   9088篇
  1995年   8450篇
  1994年   8084篇
  1993年   7587篇
  1992年   28230篇
  1991年   26994篇
  1990年   26423篇
  1989年   25362篇
  1988年   23571篇
  1987年   23194篇
  1986年   22270篇
  1985年   21164篇
  1984年   15817篇
  1983年   13485篇
  1982年   8093篇
  1979年   14595篇
  1978年   10214篇
  1977年   8634篇
  1976年   8149篇
  1975年   8965篇
  1974年   10701篇
  1973年   10186篇
  1972年   9667篇
  1971年   8920篇
  1970年   8586篇
  1969年   8035篇
  1968年   7688篇
  1967年   7092篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
71.
A case of seminoma in a monorchid adult guinea fowl (Numida meleagris) is described. Grossly, a right enlarged testis, which was soft in consistency, and white to pale in colour with few spots of haemorrhages was observed. Histologically, the testicle revealed diffusely spread sheets of tumour cells. The cells were large pleomorphic with eccentrically placed hyperchromic nuclei. Mitotic figures were evident. A scanty fibrous stroma, containing lymphocytes and histiocytes, separating the groups of tumour cells, along with few areas of haemorrhages were observed. Occurrence of seminoma in guinea fowl is unusual and hence reported.  相似文献   
72.
73.
74.
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis.  相似文献   
75.
76.
AIM: Cardiovascular risk factors can be present in children and young adults. We previously found abnormal microvascular function in children who had glucose intolerance and insulin resistance. The aim of the present study was to investigate whether they also have abnormalities in left ventricular mass (LVM) and arterial stiffness. METHODS: We measured heart dimensions and LVM using echocardiography, and arterial stiffness using pulse wave analysis in 23 children with good glucose handling (postfeeding glucose: 3.9 to 5 mmol/L) and 21 with poor glucose handling (7.7 to 11.4 mmol/L). RESULTS: The time to pulse reflection was slightly shorter in the poorer glucose handlers (mean+/-SD: 143+/-10 vs 153+/-20 ms, P=0.04), suggestive of increased arterial stiffness. Also in this group, there were significant relationships between intraventricular septal thickness, blood pressure and body mass index, but not in the normal glucose handlers. CONCLUSIONS: We have found that normal children who are in the lowest quintile of glucose tolerance in comparison with their peers are exhibiting the first signs of arterial stiffening. In addition, we have seen the beginnings of a relationship between blood pressure, body mass index and left ventricular enlargement in this group. While these changes may not yet be clinically significant, their emergence might be further evidence of early predisposition to cardiovascular disease.  相似文献   
77.
目的:描述胚胎种植前遗传诊断在1例携带Ⅰ型白细胞黏附缺陷病(LAD-1)携带者并完成健康妊娠夫妇中的应用。设计:病例报道。机构:大学医院生殖中心。患者:1例男女双方都是LAD-1携带者的夫妇,女方CD18基因的外显子4携带有G400A置换,男方的外显子5携带有C562T置换。干预:标准体外受精(IVF)后第3天行卵裂期活检和分裂球遗传分析以检测2处突变以及21号染色体标记物。主要观察指标:1个未罹患LAD-1婴儿的出生。结果:得到15个卵母细胞,其中10个受精。8个胚胎适宜胚胎活组织检查。  相似文献   
78.
Setting goals to maintain hope.   总被引:3,自引:0,他引:3  
  相似文献   
79.
80.
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