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   45304篇
  免费   5125篇
  国内免费   61篇
耳鼻咽喉   634篇
儿科学   1267篇
妇产科学   1262篇
基础医学   7010篇
口腔科学   1059篇
临床医学   6150篇
内科学   8458篇
皮肤病学   593篇
神经病学   3657篇
特种医学   1648篇
外国民族医学   1篇
外科学   6067篇
综合类   916篇
一般理论   29篇
预防医学   4672篇
眼科学   676篇
药学   3639篇
中国医学   61篇
肿瘤学   2691篇
  2021年   621篇
  2020年   410篇
  2019年   699篇
  2018年   826篇
  2017年   586篇
  2016年   734篇
  2015年   770篇
  2014年   1069篇
  2013年   1615篇
  2012年   2103篇
  2011年   2174篇
  2010年   1243篇
  2009年   1124篇
  2008年   1901篇
  2007年   1963篇
  2006年   1921篇
  2005年   1879篇
  2004年   1803篇
  2003年   1744篇
  2002年   1777篇
  2001年   1567篇
  2000年   1599篇
  1999年   1382篇
  1998年   630篇
  1997年   529篇
  1996年   444篇
  1995年   480篇
  1994年   445篇
  1993年   419篇
  1992年   1121篇
  1991年   1054篇
  1990年   1037篇
  1989年   969篇
  1988年   888篇
  1987年   912篇
  1986年   874篇
  1985年   896篇
  1984年   708篇
  1983年   605篇
  1982年   436篇
  1981年   354篇
  1980年   369篇
  1979年   582篇
  1978年   443篇
  1977年   367篇
  1976年   374篇
  1974年   379篇
  1973年   333篇
  1972年   338篇
  1971年   305篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
101.
The determination of nasal airway resistance by the technique of anterior rhinomanometry is made difficult by several factors. Among these are the variability in the breath by breath measurement of airflow and pressure, the effect of under or over breathing, and the ability to produce a smooth transition between inspiration and expiration during which period the measurements are made. To overcome some of these problems a standard procedure has been developed (in our laboratory) for active anterior rhinomanometry. The nasal resistance is calculated from the mean of three sets of three readings with a rest interval between each set. To enable the procedure to be carried out with consistency it has been implemented on a BBC microcomputer. This enables a breathing guide to be provided for the subject, as well as providing a display of each flow pressure curve, a display of the mean curve, plus and minus one standard deviation, and the calculation of left, right and total nasal airway resistance.  相似文献   
102.
103.
Prevalence of smoking in a diabetic population: the need for action   总被引:1,自引:0,他引:1  
Smoking habits in insulin-treated diabetics in Nottinghamshire (UK) and clinic-attending diabetics in Nottingham have been analysed. Compared with the general population, the prevalence of current cigarette smoking is significantly less (p less than 0.001) in both diabetic men and women older than 50 years. Fewer diabetic men over 60 years have ever smoked than in the general population (p less than 0.001) but this finding does not apply to diabetic women. While intervention probably plays some part in this lower prevalence, the most likely explanation is the multiplicative effect of both smoking and diabetes to produce high mortality risks. Actuarial analysis of insulin-treated clinic attenders diagnosed after 1970 showed that at most 14% (95% confidence interval [Cl] 9-18%) of the 183 who smoked at diagnosis had given up 5 years later while a minimum of 8% (95% Cl, 6-11%) of the 313 who were non-smokers had started smoking. Information about the patterns of smoking in patients with chronic disease is incomplete and it appears that too little is being done in clinical services which provide long-term management for these patients to either discourage smoking or determine why some patients give up smoking but others do not.  相似文献   
104.
Two hydroxyl containing dithiocarbamates, sodium N-methyl-D-glucamine dithiocarbamate (NaG) and sodium dihydroxyethyl dithiocarbamate (NaY) have been examined as agents for the control of the renal dysfunction in rats given cisplatin. Of these, NaG was found to be the more effective in controlling such renal dysfunction when administered at 1 and 3 h after 5 mg cisplatin kg-1, i.p. Renal function was examined 5 days after the administration of cisplatin by measurement of serum and urinary levels of creatinine and urea, creatinine clearance, serum and urinary levels of Na+, K+, Mg2+, Ca2+, as well as the concentrations of these ions in the renal medulla and cortex. Treatment of rats given cisplatin with NaG at 1 and 3 h post cisplatin resulted in indices of renal function which were not significantly different from those of animals which had received no cisplatin. The sole difference was found to be a slight increase in renal cortical Na+ concentration.  相似文献   
105.
D A Warrell  J Shaheen  P D Hillyard  D Jones 《Toxicon》1991,29(10):1263-1265
A young woman was bitten on the shoulder by a female Steatoda nobilis spider, in Worthing on the south coast of England. She noticed intense radiating pain, local sweating (indicating parasympathetic stimulation) and feverishness. This immigrant species from the Canary Islands has established itself along the south coast of England in recent years. Like the related Mediterranean species S. paykulliana, S. nobilis may be of medical importance and deserves further study.  相似文献   
106.
背景日常生活中,自闭症患者核心社交不足的表现比外在实验任务中的表现要显著得多。为了使实验测量符合临床观察,我们介绍一种新方法,即在一个模拟日常需要的设置中采用社会监测的定量非典型性策略。把增强的社会生态有效性对这两组的影响最大化,同时评估实验变量相对的社会能力成果测量的效用。方法在观察社会场景时,用眼睛追踪技术测量目测定位,对象是15个有感知能力的自闭症男人和15个年龄、性别与言语IQ相称的控制主体。我们编码4个可靠的定位区域:嘴、眼睛、身体和目标。统计学分析把这两组定位在兴趣区域上的时间和社会能力成果测量作了比较。(比如日常社会调整和自闭症患者的社会症状的标准化测量)结果在四个区域中都观察到这两组间的重大不同。自闭症的最佳预报器是眼睛区域上的定位时间减少。定位在嘴巴上还是定位在目标上与社交机能紧密相关:增加对嘴的注意预示着改良的社会适应性和较少的自闭症社会损伤,而花更多时间注意目标则预示着相反的关系。结论在观察自然社会情形时,自闭症个体表现出社会视觉追击的反常模式,即眼睛不再那么突出,而嘴巴、身体和目标却越加突出。定位在嘴巴和目标(而不是眼睛)上的时间是社会能力的强有力指示器。  相似文献   
107.
Background Dendritic cells (DC) mediate inflammation in rodent models of allergic airway disease, but the role played by human respiratory‐tract DC (hRTDC) in atopic asthma remains poorly defined. Recent data suggest that CD1 antigen presentation by hRTDC may contribute to asthma pathogenesis. Objective To investigate the influence of hRTDC on the balance between atopy and allergic asthma in human subjects and to determine whether CD1 expression by hRTDC is modulated during asthmatic inflammation. Methods Sputum cells were induced from steroid‐naïve, allergen‐challenged and allergen‐naïve subjects (atopic asthmatics, atopic non‐asthmatics and non‐atopic controls). hRTDC were identified using monoclonal antibody labelling and analysis by flow cytometry. Results hRTDC stained HLA‐DR+ (negative for markers of other cell lineages) were predominantly myeloid and comprised ∼0.5% of viable sputum cells. Sputum cells were potent stimulators of allogeneic CD4+ naïve T cells and enrichment/depletion experiments correlated stimulatory potency with DC numbers. Sputum contained cells that exhibited typical dendritic morphology when analysed by electron microscopy. Myeloid hRTDC were endocytically active, but uptake of FITC‐dextran was enhanced in cells from asthmatics (P<0.001). Despite their increased endocytic capacity, asthmatic myeloid hRTDC appeared mature and expressed increased levels of maturation markers (P<0.05–P<0.001), CD1c, CD1d and langerin (P<0.05). CD1c expression by asthmatic myeloid hRTDC was enhanced upon in vivo allergen challenge (three to ninefold within 24 h; P<0.05). CD11cCD123high hRTDC were only detected in asthmatic sputum and were increased in number following allergen challenge. Conclusion Despite limited cell numbers, it proved possible to analyse human RTDC in induced sputum, providing evidence that increased antigen uptake and enhanced CD1 presentation by activated hRTDC may contribute to allergic airway disease. CD1 presentation by hRTDC in atopic asthma may therefore constitute a novel target for future intervention strategies.  相似文献   
108.
Imipenem/cilastatin therapy of infections in cancer patients   总被引:2,自引:0,他引:2  
Imipenem/cilastatin was administered during 153 febrile episodes occurring in cancer patients and the response rate was 68%. Considering only documented infections the response rate was 71%. Patients who received imipenem as initial therapy had a higher response rate than patients who received it after failing other antibiotics (77% versus 68%). The overall response rates for septicemias and pneumonias were 75% and 58%. Among the 57 gram-negative infections 77% responded, but the response rate was substantially higher if imipenem was used as initial therapy (94% versus 69%). The poorest response rate was observed when imipenem was given as secondary therapy for Pseudomonas infections (50%), but most of these patients had failed to respond to other appropriate antibiotics. The only serious side effect was seizures which occurred in ten patients, although eight of them had other predisposing factors. Imipenem appears to be a useful antibiotic for treatment of infections, even in neutropenic cancer patients.  相似文献   
109.
Summary A randomised, comparative study is reported of single intravenous doses of cephradine 2 g or cefuroxime 1.5 g given as prophylactic cover for total hip replacements in 40 patients. The serum and bone levels of cephalosporin achieved were higher in the cephradine treated group in proportion to the higher dose employed. Both agents provided adequate bone levels on average, cephradine 25.34 mcg/g, cefuroxime 17.39 mcg/g, although bone penetration was more variable with cefuroxime.
Résumé Dans cette étude comparative randomisée, 40 patients ont reçu une dose intraveineuse unique de 2 g de céphradine ou de 1,5 g de céfuroxime en tant que couverture prophylactique d'arthroplastie totale de hanche. Les concentrations sériques et osseuses de céphalosporine ont été plus élevées dans le groupe traité par la céphradine, en rapport avec l'utilisation d'une dose plus importante. Des concentrations osseuses adéquates ont été obtenues en moyenne avec les deux produits (25,34 mcg/g avec la céphradine et 17,39 mcg/g avec le céfuroxime) bien que la pénétration osseuse ait été plus variable avec le céfuroxime.
  相似文献   
110.
A case of hospital acquired endocarditis due to Acinetobacter calcoaceticus in a severely burned patient is presented. Both aortic and mitral native valves were affected and the organism was resistant to most antimicrobial agents.  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