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   1284篇
  免费   83篇
  国内免费   11篇
耳鼻咽喉   2篇
儿科学   89篇
妇产科学   11篇
基础医学   126篇
口腔科学   26篇
临床医学   147篇
内科学   250篇
皮肤病学   21篇
神经病学   38篇
特种医学   315篇
外科学   132篇
综合类   28篇
预防医学   44篇
眼科学   7篇
药学   78篇
肿瘤学   64篇
  2023年   4篇
  2021年   10篇
  2020年   6篇
  2019年   9篇
  2018年   18篇
  2017年   4篇
  2016年   10篇
  2015年   18篇
  2014年   22篇
  2013年   28篇
  2012年   14篇
  2011年   15篇
  2010年   32篇
  2009年   31篇
  2008年   18篇
  2007年   31篇
  2006年   26篇
  2005年   28篇
  2004年   23篇
  2003年   15篇
  2002年   20篇
  2001年   15篇
  2000年   22篇
  1999年   31篇
  1998年   99篇
  1997年   74篇
  1996年   81篇
  1995年   54篇
  1994年   58篇
  1993年   64篇
  1992年   16篇
  1991年   13篇
  1990年   19篇
  1989年   46篇
  1988年   32篇
  1987年   44篇
  1986年   25篇
  1985年   39篇
  1984年   25篇
  1983年   21篇
  1982年   25篇
  1981年   28篇
  1980年   30篇
  1979年   18篇
  1978年   21篇
  1977年   26篇
  1976年   29篇
  1975年   19篇
  1973年   3篇
  1968年   4篇
排序方式: 共有1378条查询结果,搜索用时 9 毫秒
51.
Doppler and direct measurements of right ventricle to right atrial pressure drop were made during cardiac catheterisation on 28 occasions in 26 infants with congenital heart disease. Age was 10 days to 12 months (median 4.5 months), and weight was 3.1 to 9.0 kg (median 4.7 kg). We measured peak velocity of tricuspid regurgitation by continuous wave Doppler, and the pressure drop was calculated using the modified Bernoulli equation (delta p = 4v2). There was a high correlation (r = 0.95) between direct and Doppler measurements. Doppler values tended to underestimate the right ventricle to right atrial pressure drop, but this was not of clinical significance (mean 2 mm Hg). The 95% confidence interval for the Doppler velocity was -0.41 to +0.26 m/sec, and was consistent across the range of pressures studied. Variability between observers was tested, by two observers performing sequential paired examinations on 16 newborn babies with tricuspid regurgitation. The coefficient of repeatability was 6.3 mm Hg (95% confidence interval 4.7 to 9.5 mm Hg) or 0.26 m/sec (0.18 to 0.50 m/sec). This method of right ventricular pressure estimation, validated previously only in older children and adults, is a reproducible and accurate technique in infants with tricuspid regurgitation.  相似文献   
52.
O'Meara A, Tormey W, Fitz Gerald RJ, Fitzgibbon M, Kenny D. Interpretation of random urinary catecholamines and their metabolites in neuroblastoma. Acta Paediatr 1994;83:88–92. Stockholm. ISSN 0803–5253
This study reports experience in the estimation of urinary catecholamines (uCATs) and their metabolites in the diagnosis and follow-up of neuroblastoma. Random urine samples were assayed for dopamine, noradrenaline and adrenaline, together with their metabolites 4-hydroxy 3-methoxyman-delic acid (HMMA) and homovanillic acid (HVA), using HPLC with electrochemical detection. Twenty of 21 patients had elevation of one or more uCATs metabolites at diagnosis. Patients were monitored serially from diagnosis and, in those patients who had delayed resection of primary tumour (n=13), particular attention was paid to levels at the pre-surgical evaluation as an indicator of persistence of viable disease at the time of surgery; dopamine proved to be the most accurate indicator of persistent disease at this time. Five of these patients developed recurrent disease, 4 of whom had elevation of two or more uCATs metabolites at the time of relapse. Several conclusions can be drawn from this study: (a) results for HMMA, HVA and dopamine in random urine samples will detect all but the most biochemically immature or inert tumours; (b) dopamine may be the most reliable indicator of persistent disease and (c) noradrenaline and adrenaline measurements were of little benefit. As results are Expressed in relation to urinary creatinine, excretion of which may be affected by dietary protein and is therefore not constant, borderline results should be repeated.  相似文献   
53.
A 4 year old girl treated with a standard chemotherapy protocol for acute lymphoblastic leukaemia developed hepatic candidosis during the consolidation phase. This relapsed after a prolonged course of amphotericin B and flucytosine. An eight week course of liposomal amphotericin produced a marked clinical improvement which was sustained for one year. A subsequent relapse was associated with transformation to myelodysplastic leukaemia.  相似文献   
54.
A sample of three hundred and nine alcoholic and non-alcoholic women in South Carolina were asked three family-of-origin questions that were thought to relate to the development of alcoholism. Specifically the women were asked: "While you were growing up did anyone in your family: (1) drink a lot? (2) use drugs? or (3) serve a jail sentence?" Results of multivariate odds ratio analyses indicate that alcoholic women were 7.31 times more likely to indicate a family member who drank a lot, 3.57 times more likely to report a family member who used drugs, and 5.6 times more likely to report a family member who served a jail sentence in their families of origin. The prediction of alcoholism by any of these family of origin variables did not differ as a function of age or race. These data suggest that policy makers may contribute to improved outcome measures by providing attention to children passing through these difficulties.  相似文献   
55.
It is imperative to know the details of the anatomy of the nose before understanding any surgical procedure performed on the nose. The details presented in this article should help the experienced and the novice surgeon accomplish the difficult task of a rhinoplasty.  相似文献   
56.
57.
58.
59.
1. 5-Hydroxytryptamine (5-HT) exerts both contractile and relaxant effects in the marmoset isolated aorta, actions that are unaffected by the 5-HT2 antagonist ketanserin. The aim of the present study was to define the receptors mediating the contractile activity of 5-HT in the marmoset aorta.
2. Contractile responses were elicited in aortic rings that were either: (i) precontracted submaximally with the thromboxane A2 agonist U44069 in order to amplify the responses; or (ii) exposed to N ω-nitro- L -arginine (100 μmol/L) plus LY 53857 (0.1 μmol/L; a 5-HT2 receptor antagonist shown previously to inhibit relaxation). The effect of 5-HT on adenosine 3',5'-cyclic monophosphate (cAMP) formation was also investigated.
3. The effects of agonists and antagonists comprised: (i) agonist potencies in the order 5-carboxamidotryptamine > 5-HT > sumatriptan > 8-hydroxy-2-(di- n -propylamino)tetralin; (ii) inhibition of contractile action of 5-HT by the 5-HT1D antagonist GR 127935; (iii) a contractile response to methysergide; (iv) a lack of effect of tropisetron, an antagonist of 5-HT3 and 5-HT4 receptors; and (v) inhibition of forskolin-stimulated cAMP formation by 5-HT (in the presence of LY 53857), indicative of negative coupling to adenylate cyclase.
4. The above effects fulfil the criteria for a 5-HT1-like receptor. In view of the previous finding that this contractile response is insensitive to ketanserin, it is concluded that the contractile effects of 5-HT in the marmoset aorta are mediated exclusively by a 5-HT1-like receptor.  相似文献   
60.
In an outbreak of gastroenteritis affecting 43 people, cryptosporidium and campylobacter were isolated from stool specimens and in two cases dual infection was found. All the cases had drunk unboiled water from a private untreated water supply. Investigations revealed the carcasses of three lambs in a collection chamber connected with the water supply, and these, or run-off of slurry from surrounding fields, were the presumed source of contamination. Issues relating to the maintenance and monitoring of private water supplies are discussed. Problems with such supplies include old piping, proximity of livestock, inadequate knowledge of the layout and limited resources for monitoring and maintenance.  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