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   26647篇
  免费   1475篇
  国内免费   78篇
耳鼻咽喉   412篇
儿科学   1141篇
妇产科学   870篇
基础医学   4299篇
口腔科学   596篇
临床医学   2202篇
内科学   5301篇
皮肤病学   553篇
神经病学   2601篇
特种医学   1184篇
外国民族医学   14篇
外科学   3803篇
综合类   129篇
一般理论   3篇
预防医学   1396篇
眼科学   502篇
药学   1382篇
中国医学   19篇
肿瘤学   1793篇
  2022年   214篇
  2021年   371篇
  2020年   239篇
  2019年   326篇
  2018年   415篇
  2017年   354篇
  2016年   494篇
  2015年   481篇
  2014年   653篇
  2013年   840篇
  2012年   1188篇
  2011年   1268篇
  2010年   650篇
  2009年   710篇
  2008年   1157篇
  2007年   1259篇
  2006年   1171篇
  2005年   1192篇
  2004年   993篇
  2003年   980篇
  2002年   908篇
  2001年   913篇
  2000年   936篇
  1999年   794篇
  1998年   378篇
  1997年   303篇
  1996年   248篇
  1995年   230篇
  1994年   191篇
  1993年   197篇
  1992年   483篇
  1991年   513篇
  1990年   499篇
  1989年   418篇
  1988年   403篇
  1987年   416篇
  1986年   400篇
  1985年   400篇
  1984年   276篇
  1983年   218篇
  1982年   149篇
  1981年   148篇
  1979年   260篇
  1978年   190篇
  1977年   160篇
  1976年   159篇
  1975年   169篇
  1974年   192篇
  1973年   167篇
  1972年   155篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
用混合粘合剂碳糊电极测定丁螺环酮   总被引:6,自引:1,他引:5  
用混合粘合剂碳糊电极测定丁螺环酮张正奇,曾鸽鸣,刘传桂,黎艳飞(湖南大学化学化工系,长沙410082)碳糊电极无毒,制作方便,表面更新容易,应用电位范围广,在药物分析中已有应用[1~5]。我们在液体石腊中加入添加剂,组成混合粘合剂,可显著改善电极的检...  相似文献   
52.
As natural rubber latex (latex) has become more widespread in our environment, physicians have become increasingly aware of the problem of possible allergic reactions. Many fatal and near-fatal incidents have been reported (mainly during surgery) (1—3) and data has been published on groups frequently exposed to latex, such as patients with spina bifida (4—9), healthcare professionals (10—12) and occupationally exposed persons (13). The incidence of latex allergy in children seems to be increasing (14). Tests are therefore needed which can reliably detect sensitization to latex. Our aim was to compare the diagnostic accuracy of three commercial immunoassays for measuring specific IgE in serum to latex.  相似文献   
53.
Summary. In order to investigate fat metabolism and the regulation of lipolysis and blood fuel metabolites by insulin, nine patients with chronic obstructive pulmonary disease (COPD) with chronic hypoxaemia and seven healthy control subjects of similar age were investigated by determination of the turnover rate of free fatty acids (TOR), using 1-14C-oleic acid as a tracer, and arterial concentrations of FFA, glycerol and 3-hydroxybutyrate. The measurements were performed in the basal state and during insulin and glucose infusion, aiming at euglycaemia at insulin levels of 50 and 100 mU l-1. The subjects' ages were 64±2.7 and 66±1.1 (mean±SEM) years in the COPD and control groups, respectively. TOR was 0.73±0.06 and 0.52±0.02 mmol min-1 (P<0.05) in the basal state, 0.33±0.04 and 0.30±0.02 at an insulin level of 50 mU I-1 and 0.32±0.08 and 0.24±0.02 at an insulin level of 100 mU I-1, in the COPD and control groups, respectively. Arterial FFA concentration was 0.98±0.08 and 0.75±0.06 mmol 1-1 (P<0.05) in the basal state in the COPD and control groups, respectively. During the clamp, the decrease in FFA mirrored that in TOR. The results show that the state of lipolysis is increased in severe COPD patients with chronic hypoxaemia. Furthermore, the results suggest a reduced effect of insulin in lipolysis.  相似文献   
54.
A series of substituted indolyldihydropyridazinones and related compounds 1-18 were synthesized and evaluated for positive inotropic activity. In rats, most of these indole derivatives produced a dose-related increase in myocardial contractility with little effect on heart rate and blood pressure. Compound 13, 4,5-dihydro-5-methyl-6-(2-pyridin-4-yl-1H-indol-5-yl)pyrazin-3(2H) -one (BM 50.0430), was further investigated in cats. The increase in contractility in this animal model was not mediated via stimulation of beta-adrenergic receptors. After oral administration of 1 mg/kg to conscious dogs, compound 13 and pimobendan were still active after 6.5 h. However, the cardiotonic effect of 13 was at least 2-fold that of pimobendan after this period of time. The structural requirements necessary for optimal cardiotonic activity within this novel class of indole derivatives are a heterocyclic aromatic ring in position 2, a hydrogen or a methyl group in position 3, and a dihydropyridazinone ring system in position 5 of the indole.  相似文献   
55.
Ciclesonide is an onsite-activated inhaled corticosteroid (ICS) for the treatment of asthma. This study compared the efficacy, safety and effect on quality of life (QOL) of ciclesonide 160 microg (ex-actuator; nominal dose 200 microg) vs. budesonide 400 microg (nominal dose) in children with asthma. Six hundred and twenty-one children (aged 6-11 yr) with asthma were randomized to receive ciclesonide 160 microg (ex-actuator) once daily (via hydrofluoroalkane metered-dose inhaler and AeroChamber Plus spacer) or budesonide 400 microg once daily (via Turbohaler) both given in the evening for 12 wk. The primary efficacy end-point was change in forced expiratory volume in 1 s (FEV1). Additional measurements included change in daily peak expiratory flow (PEF), change in asthma symptom score sum, change in use of rescue medication, paediatric and caregiver asthma QOL questionnaire [PAQLQ(S) and PACQLQ, respectively] scores, change in body height assessed by stadiometry, change in 24-h urinary cortisol adjusted for creatinine and adverse events. Both ciclesonide and budesonide increased FEV1, morning PEF and PAQLQ(S) and PACQLQ scores, and improved asthma symptom score sums and the need for rescue medication after 12 wk vs. baseline. The non-inferiority of ciclesonide vs. budesonide was demonstrated for the change in FEV1 (95% confidence interval: -75, 10 ml, p = 0.0009, one-sided non-inferiority, per-protocol). In addition, ciclesonide and budesonide showed similar efficacy in improving asthma symptoms, morning PEF, use of rescue medication and QOL. Ciclesonide was superior to budesonide with regard to increases in body height (p = 0.003, two-sided). The effect on the hypothalamic-pituitary-adrenal axis was significantly different in favor of ciclesonide treatment (p < 0.001, one-sided). Both ciclesonide and budesonide were well tolerated. Ciclesonide 160 microg once daily and budesonide 400 microg once daily were effective in children with asthma. In addition, in children treated with ciclesonide there was significantly less reduction in body height and suppression of 24-h urinary cortisol excretion compared with children treated with budesonide after 12 wk.  相似文献   
56.
57.
58.
A patient with group B streptococcal endocarditis and large vegetations resembling mitral valve myxoma is described. Group B streptococcal endocarditis and the differential diagnosis of vegetations and cardiac tumors are briefly reviewed.  相似文献   
59.
Metastatic bone disease from occult carcinoma: a profile   总被引:3,自引:0,他引:3  
Summary To assess the general profile of metastatic bone disease from occult primary carcinoma, the records of 172 patients with skeletal metastases seen between 1965 and 1985 were reviewed. In 51 patients (30%), the origin of the primary could not be identified when bone metastases were first diagnosed. This group were predominantly male with a high incidence of spinal metastases, cord compression and pathological fractures, and a significantly shorter (P<0.1) survival compared with bony metastases when the primary was known. The site of the primary was established in 33 patients (65%), mostly at autopsy. Lung carcinoma was by far the most common primary tumour in 52% of the cases, while it accounted for only 7% of those with a diagnosed primary. We believe that the onset of bony metastases from an occult source must initially raise the possibility of lung carcinoma. If the primary remains undetected, it appears justifiable to assume it to be in the lung, since the probability of a missed lung tumour being responsible for the metastases is high.
Résumé Les auteurs ont revu les observations de 172 malades porteurs de métastases osseuses, vus entre 1965 et 1985, afin d'apprécier l'aspect général des métastases provenant d'un cancer primitif méconnu. Chez 51 malades (30%) l'origine du cancer primitif n'avait pu être découverte lors du diagnostic de métastase osseuse. Ce groupe était à prédominance masculine, comportant un nombre élevé d'atteintes vertébrales, de compressions médullaires et de fractures pathologiques, et un taux de survie significativement plus court (P<0,1) comparativement à celui des métastases d'un cancer primitif connu. La localisation du cancer primitif a été découverte dans 33 cas (65%), la plupart du temps à l'autopsie. Le cancer du poumon était le plus fréquemment en cause (52%), alors qu'il n'était responsable que de 7% des cas quand le cancer primitif était connu. Il semble que l'apparition de métastases osseuses d'origine inconnue doive faire évoquer d'emblée la possibilité d'un cancer du poumon. Si le cancer primitif ne peut être découvert il est vraisemblable qu'il siège au niveau du poumon, la probabilité d'un cancer du poumon méconnu, responsable des métastases, étant élevée.


Presented in part at the International Symposium on Bone Metastases, Rome, Italy, June 1986  相似文献   
60.
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