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   46686篇
  免费   5247篇
  国内免费   64篇
耳鼻咽喉   634篇
儿科学   1314篇
妇产科学   1538篇
基础医学   7068篇
口腔科学   1077篇
临床医学   6915篇
内科学   8511篇
皮肤病学   644篇
神经病学   3637篇
特种医学   1695篇
外国民族医学   1篇
外科学   6073篇
综合类   963篇
一般理论   29篇
预防医学   4756篇
眼科学   680篇
药学   3672篇
中国医学   61篇
肿瘤学   2729篇
  2021年   622篇
  2020年   440篇
  2019年   716篇
  2018年   857篇
  2017年   663篇
  2016年   792篇
  2015年   849篇
  2014年   1131篇
  2013年   1669篇
  2012年   2136篇
  2011年   2219篇
  2010年   1312篇
  2009年   1181篇
  2008年   1922篇
  2007年   1996篇
  2006年   1947篇
  2005年   1892篇
  2004年   1807篇
  2003年   1768篇
  2002年   1789篇
  2001年   1592篇
  2000年   1601篇
  1999年   1422篇
  1998年   703篇
  1997年   615篇
  1996年   533篇
  1995年   560篇
  1994年   499篇
  1993年   452篇
  1992年   1137篇
  1991年   1074篇
  1990年   1039篇
  1989年   979篇
  1988年   903篇
  1987年   917篇
  1986年   892篇
  1985年   914篇
  1984年   717篇
  1983年   614篇
  1982年   445篇
  1981年   360篇
  1980年   376篇
  1979年   582篇
  1978年   456篇
  1977年   376篇
  1976年   381篇
  1974年   379篇
  1973年   334篇
  1972年   338篇
  1971年   304篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
43.
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   
44.
45.
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   
46.
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   
47.
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   
48.
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   
49.
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   
50.
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