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   11099篇
  免费   2622篇
  国内免费   135篇
耳鼻咽喉   379篇
儿科学   226篇
妇产科学   279篇
基础医学   480篇
口腔科学   188篇
临床医学   3150篇
内科学   2134篇
皮肤病学   338篇
神经病学   813篇
特种医学   406篇
外科学   1526篇
综合类   389篇
现状与发展   2篇
一般理论   2篇
预防医学   1977篇
眼科学   159篇
药学   371篇
  1篇
中国医学   111篇
肿瘤学   925篇
  2024年   81篇
  2023年   432篇
  2022年   178篇
  2021年   371篇
  2020年   565篇
  2019年   248篇
  2018年   654篇
  2017年   653篇
  2016年   677篇
  2015年   766篇
  2014年   799篇
  2013年   1134篇
  2012年   531篇
  2011年   465篇
  2010年   592篇
  2009年   689篇
  2008年   409篇
  2007年   328篇
  2006年   397篇
  2005年   296篇
  2004年   231篇
  2003年   189篇
  2002年   160篇
  2001年   220篇
  2000年   169篇
  1999年   178篇
  1998年   285篇
  1997年   301篇
  1996年   318篇
  1995年   254篇
  1994年   175篇
  1993年   125篇
  1992年   104篇
  1991年   97篇
  1990年   84篇
  1989年   99篇
  1988年   82篇
  1987年   67篇
  1986年   55篇
  1985年   66篇
  1984年   53篇
  1983年   49篇
  1982年   34篇
  1981年   48篇
  1980年   21篇
  1979年   18篇
  1978年   19篇
  1977年   18篇
  1976年   16篇
  1974年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
目的 探讨在苯妥英钠(Phenytoin,PHT)促进大鼠牙周膜干细胞(Rat periodontal ligament stem cells,rPDLSCs)、大鼠骨髓间充质干细胞(Rat Bone Marrow Mesenchymal Stem Cells,rBMMSCs)黏附于牙骨质过程中,整合素α5β1(Integrin α5β1)起到的作用。方法 提取大鼠BMMSCs和PDLSCs,培养并纯化。通过细胞鉴定后,将获得的两种细胞各分为4组:40 mg/L PHT处理组、40 mg/L PHT+整合素α5抗体处理组、40 mg/L PHT+整合素β1抗体处理组、PBS处理组,每组细胞放入置有牙骨质片的96孔板处理4 h后,检测黏附于牙骨质片上的细胞量并做以比较。最后,利用qRT-PCR和Western blot检测40 mg/L PHT组与对照组细胞的整合素α5、β1亚基的mRNA与蛋白表达量。结果 40 mg/L PHT可促进rBMMSCs及rPDLSCs黏附于牙骨质片,加入整合素α5、β1抗体后,均明显抑制了40 mg/L PHT对rBMMSCs、rPDLSCs黏附于牙骨质的促进作用(P<0.01)。qRT-PCR、Western-blot结果显示PHT处理组的整合素α5、β1亚基表达量高于空白对照组(P<0.05)。结论 40 mg/L PHT能促进rBMMSCs、rPDLSCs黏附于牙骨质,该作用与整合素α5β1的表达上调密切相关。  相似文献   
5.
6.
We present a patient with a history of coronary artery disease and exertional angina after an acute anterior myocardial infarction. Angiography and ventriculography revealed multivessel coronary artery disease and a large apical aneurysm. Echocardiography and gated SPECT studies were performed for further evaluation of ischemia and assessment of left ventricular function. Gated SPECT and echocardiography failed to detect a large apical aneurysm due to a hyperdynamic left ventricular wall at the neck of the aneurysm. This case demonstrates the importance of using multiple imaging modalities in the evaluation of ventricular function in the setting of coronary artery disease.  相似文献   
7.
8.
Stuart Cathcart  BA    Donald Pritchard  PhD 《Headache》1998,38(3):214-221
An exploratory study was conducted examining arousal-related moods and episodic tension-type headache. Twelve subjects meeting International Headache Society criteria for episodic tension-type headache and 12 headache-free controls recorded headache activity and mood eight times daily for 14 consecutive days. Moods were measured using the Activation-Deactivation Adjective Check List, a self-report list that subjectively represents general arousal along two dimensions of Tension and Energy. Headache subjects had higher Tension levels than controls even in the absence of pain, and greater variation in this dimension as well. Within the headache group, Tension during pain-free periods was significantly lower than when experiencing headache, and was correlated with headache activity. The results were taken to support Thayer's (1989) biopsychological model of mood and arousal, and are discussed in terms of the model's heuristic value for general arousal and headache research.  相似文献   
9.
Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects.  相似文献   
10.
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