全文获取类型
收费全文 | 1298746篇 |
免费 | 87076篇 |
国内免费 | 2308篇 |
专业分类
耳鼻咽喉 | 17371篇 |
儿科学 | 42797篇 |
妇产科学 | 33065篇 |
基础医学 | 199574篇 |
口腔科学 | 39922篇 |
临床医学 | 112420篇 |
内科学 | 250064篇 |
皮肤病学 | 30685篇 |
神经病学 | 94795篇 |
特种医学 | 46312篇 |
外国民族医学 | 161篇 |
外科学 | 190018篇 |
综合类 | 23683篇 |
现状与发展 | 3篇 |
一般理论 | 329篇 |
预防医学 | 101624篇 |
眼科学 | 29845篇 |
药学 | 97271篇 |
3篇 | |
中国医学 | 3874篇 |
肿瘤学 | 74314篇 |
出版年
2021年 | 11711篇 |
2019年 | 11697篇 |
2018年 | 16594篇 |
2017年 | 12512篇 |
2016年 | 13373篇 |
2015年 | 15057篇 |
2014年 | 20593篇 |
2013年 | 30082篇 |
2012年 | 41601篇 |
2011年 | 44207篇 |
2010年 | 25319篇 |
2009年 | 23405篇 |
2008年 | 39777篇 |
2007年 | 42687篇 |
2006年 | 42544篇 |
2005年 | 40943篇 |
2004年 | 39764篇 |
2003年 | 37464篇 |
2002年 | 35171篇 |
2001年 | 60587篇 |
2000年 | 62083篇 |
1999年 | 51432篇 |
1998年 | 13910篇 |
1997年 | 11856篇 |
1996年 | 12416篇 |
1995年 | 11562篇 |
1994年 | 10741篇 |
1992年 | 38529篇 |
1991年 | 38607篇 |
1990年 | 37785篇 |
1989年 | 37045篇 |
1988年 | 33773篇 |
1987年 | 33080篇 |
1986年 | 31219篇 |
1985年 | 29631篇 |
1984年 | 21827篇 |
1983年 | 18520篇 |
1982年 | 10307篇 |
1979年 | 20285篇 |
1978年 | 14451篇 |
1977年 | 12175篇 |
1976年 | 11647篇 |
1975年 | 13118篇 |
1974年 | 15465篇 |
1973年 | 14739篇 |
1972年 | 14015篇 |
1971年 | 13230篇 |
1970年 | 12629篇 |
1969年 | 11811篇 |
1968年 | 11013篇 |
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
51.
AIMS: To examine the effects of agents that alter potassium adenosine triphosphate (KATP) channel activity in beta-cells on cognitive function and counterregulatory hormone responses during acute hypoglycaemia, given the physiological similarities between the pancreatic beta-cell and the hypothalamic glucose-sensitive neurones (GSN) and the widespread distribution of sulphonylurea receptors in neuronal cells throughout the brain. METHODS: Ten healthy males were studied on four occasions and in random order underwent three stepped hypoglycaemic (plasma glucose aims: 3.4, 2.8, 2.4 mmol/l) and one euglycaemic (plasma glucose aim: 5 mmol/l) insulin clamps. Prior to each hypoglycaemic study, volunteers received either 10 mg glibenclamide, or 5 mg/kg diazoxide or placebo orally. Cognitive function, symptom scores and counterregulatory hormone responses were measured at each glycaemic level. RESULTS: There was no statistically significant effect of either drug on the symptoms generated or the counterregulatory hormonal response during hypoglycaemia. However, cognitive function was better preserved during hypoglycaemia in the glibenclamide-treated arm, particularly four-choice reaction time which deteriorated at a plasma glucose 2.5 mmol/l compared with 3.0 mmol/l with diazoxide (P = 0.015) and 2.9 mmol/l with placebo (P = 0.114). CONCLUSIONS: Single doses of pharmacological agents which alter membrane KATP channel activity do not affect the counterregulatory response to hypoglycaemia but may modify cognitive function during cerebral glucopenia. The unexpected effects of glibenclamide on cortical function suggest a novel action of sulphonylureas that warrants further investigation. 相似文献
52.
D Gröne† R Treudler† EM de Villiers‡ R Husak† CE Orfanos† ChC Zouboulis†§ 《Journal of the European Academy of Dermatology and Venereology》2006,20(2):202-205
Cidofovir is an acyclic nucleoside phosphonate with broad-spectrum activity against DNA viruses, including human papilloma virus (HPV). However, data on the efficacy of cidofovir in an immunosuppressive setting remain contradictory. We report for the first time on the promotion of the healing of recalcitrant warts in a patient with myelodysplastic syndrome with intravenous cidofovir treatment. 相似文献
53.
S Chinn S H Downs J M Anto M W Gerbase B Leynaert R de Marco C Janson D Jarvis N Künzli J Sunyer C Svanes E Zemp U Ackermann-Liebrich P Burney 《The European respiratory journal》2006,28(4):763-771
The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males. 相似文献
54.
M. C. van den Heuvel K. P. de Jong M. Boot M. J. H. Slooff S. Poppema A. S. H. Gouw 《American journal of transplantation》2006,6(11):2660-2671
The finer branches of the biliary tree (FBBT) contain a regenerative compartment. We hypothesized that preservation of the FBBT together with its microvasculature will lead to recovery of biliary damage and prolonged preservation of bile ductules during the development of chronic liver allograft rejection. The interlobular bile ducts, portal bile ductules and extraportal biliary cells with and without microvessels were studied in sequential biopsies in five patients who fulfilled the Banff criteria of early chronic rejection (CR) (imminence group). Biopsies of CR patients (n = 12) served as controls. Biopsies were double immunostained with CD34 (microvessels) and cytokeratin 7 (biliary structures). Proliferation and proangiogenic activity were assessed with Ki67 and VEGF-A immunostaining. Severe damage of bile ducts in the imminence group did not progress to significant bile duct loss. This was associated with a high proliferative activity in all biliary structures and preservation of the microvascular compartment. VEGF-A expression was increased in all but the reperfusion biopsies. In conclusion, both regenerative activity of the FBBT and an intact microvascular compartment are associated with less damage of the biliary tree and could therefore be prerequisites for biliary regeneration. 相似文献
55.
P F Plouin D L Clement H Boccalon J Dormandy I Durand-Zaleski G Fowkes L Norgren T Brown 《International angiology》2003,22(4):333-339
Atherosclerotic renal artery stenosis (ARAS) may cause hypertension, progressive renal failure, and recurrent pulmonary edema. It typically occurs in high risk patients with coexistent vascular disease elsewhere. Most patients with ARAS are likely to die from coronary heart disease or stroke before end-stage renal failure occurs. Recent controlled trials have shown that most patients undergoing angioplasty to treat renovascular hypertension still need antihypertensive agents 6 or 12 months after the procedure. Nevertheless, the number of antihypertensive agents required to control blood pressure adequately is lower following angioplasty than for medication alone. Trials assessing the value of revascularization for preserving renal function or preventing clinical events are only in the early recruitment phase. Revascularization should be undertaken in patients with ARAS and resistant hypertension or heart failure, and probably in those with rapidly deteriorating renal function or with an increase in plasma creatinine levels during angiotensin-converting enzyme inhibition. With or without revascularization, medical therapy using antihypertensive, hypolipidemic and antiplatelet agents is necessary in almost all cases. 相似文献
56.
57.
58.
59.
Mariela Dutra Gontijo Moura Soraya de Mattos Camargo Grossmann Linaena Méricy da Silva Fonseca Maria Inês Barreiros Senna Ricardo Alves Mesquita 《Journal of oral pathology & medicine》2006,35(6):321-326
BACKGROUND: Oral hairy leukoplakia (OHL) may be an indicator of the progression of Human Immunodeficiency Virus (HIV)-induced immuno-depression, and the evaluation of risk factors leading to OHL is important in the management of these HIV-infected patients. However, there are few studies that analyze risk factors leading to OHL in the Brazilian population. The aim of this case-control study is to present data about prevalence rates and risk factors leading to OHL in a sample of HIV-infected adults in Brazil. METHODS: This case-control study included 111 HIV-infected patients treated at a clinic for sexually transmitted diseases and HIV. In the initial examinations with dentists, variables were collected from all patients. Diagnosis of OHL was performed in accordance with the International Classification System and cytological features. The Fisher and the chi-squared tests were used for statistical analysis. The proportional prevalence and odds ratio were estimated. RESULTS: Outcome presented a positive, statistically significant association among the presence of OHL and viral load of 3000 copies/mul or greater (P = 0.0001; odds ratio (OR) = 5.8), presence of oral candidiasis (P = 0.0000; OR = 11.1), previous use of fluconazole (P = 0.0000; OR = 24.6), and use of systemic acyclovir (P = 0.032; OR = 4.3). Antiretroviral medication presented a negative, statistically significant association with the presence of OHL (P = 0.002; OR = 8.4). CONCLUSIONS: Prevalence of OHL was 28.8%. Viral load, oral candidiasis, previous use of fluconazole, and systemic acyclovir were determined to be risk factors for OHL. Antiretroviral medication proved to be protective against the development of OHL. 相似文献
60.