全文获取类型
收费全文 | 2264篇 |
免费 | 110篇 |
国内免费 | 63篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 99篇 |
妇产科学 | 23篇 |
基础医学 | 238篇 |
口腔科学 | 27篇 |
临床医学 | 257篇 |
内科学 | 564篇 |
皮肤病学 | 64篇 |
神经病学 | 91篇 |
特种医学 | 332篇 |
外科学 | 201篇 |
综合类 | 31篇 |
一般理论 | 2篇 |
预防医学 | 129篇 |
眼科学 | 14篇 |
药学 | 158篇 |
中国医学 | 2篇 |
肿瘤学 | 203篇 |
出版年
2023年 | 8篇 |
2021年 | 31篇 |
2020年 | 21篇 |
2019年 | 32篇 |
2018年 | 43篇 |
2017年 | 9篇 |
2016年 | 26篇 |
2015年 | 27篇 |
2014年 | 35篇 |
2013年 | 82篇 |
2012年 | 66篇 |
2011年 | 58篇 |
2010年 | 57篇 |
2009年 | 78篇 |
2008年 | 60篇 |
2007年 | 108篇 |
2006年 | 57篇 |
2005年 | 68篇 |
2004年 | 64篇 |
2003年 | 53篇 |
2002年 | 56篇 |
2001年 | 55篇 |
2000年 | 57篇 |
1999年 | 61篇 |
1998年 | 90篇 |
1997年 | 93篇 |
1996年 | 114篇 |
1995年 | 69篇 |
1994年 | 64篇 |
1993年 | 61篇 |
1992年 | 51篇 |
1991年 | 42篇 |
1990年 | 47篇 |
1989年 | 62篇 |
1988年 | 66篇 |
1987年 | 62篇 |
1986年 | 62篇 |
1985年 | 64篇 |
1984年 | 15篇 |
1983年 | 25篇 |
1982年 | 22篇 |
1981年 | 20篇 |
1980年 | 18篇 |
1979年 | 25篇 |
1978年 | 20篇 |
1977年 | 19篇 |
1976年 | 18篇 |
1975年 | 27篇 |
1974年 | 10篇 |
1973年 | 12篇 |
排序方式: 共有2437条查询结果,搜索用时 31 毫秒
101.
102.
Objective:To investigate the wound healing properly of Napoleona vogelii leaf extract in folkloric medicine.Methods:Roth sexes of adult albino rats(n=25) were used in this study and another group(n=30) were subjected to acute toxicity test(LD_(50)) of the plant extract.For the LD_(50),three randomized groups of 5 rats were first treated with 10,100,1 000 mg/kg body weight(bw),orally.This w as followed by a second treatment of 1500,3000,and 5 000 mg/kg bw of the leaf extract with continual monitoring of the animals for mortality or non-mortality.Incision wounds(1.3cm) were created on the skin of five groups of 5 rals using surgical blade under anesthesia.The first group was topically treated with petroleum jelly alone,group 2 was topically applied 400 mg/mL w/v of the reference drug,Neobaein,while group 3-5 were topically treated with 5-50 mg/mL w/v of the plant extract,respectively.Results:The percentage yield of the extract was 49.80%w/w dry matter.The phytochemical analysis revealed several bioactive constituents including glycosides,tannins,alkaloids,perpenoids.saponins,steroids,proteins,and carbohydrates.The LD_(50) was beyond our experimental limit and was not determined.Increased concentrations(5,20,and 50mg/mL w/v) of the extract had significant(ANOVA,P0.05) healing effect on the incision wounds giving rise to 125%-140% while treatmentawith Neobacin resulted in 150% healing effect on the third treatment regimen compared to the control(100%).Conclusions:These data indicate that Napoleona vogelii leaf extract contains potent bioactive compounds containing wound healing activity,substantiating its use as a wound healer in folkloric medicine. 相似文献
103.
A Mocroft B Neesgard R Zangerle A Rieger A Castagna V Spagnuolo A Antinori FC Lampe M Youle JJ Vehreschild C Mussini V Borghi J Begovac C Duvivier HF Gunthard A Rauch J Tiraboschi N Chkhartishvili N Bolokadze F Wit JC Wasmuth S De Wit C Necsoi C Pradier V Svedhem C Stephan K Petoumenos H Garges F Rogatto L Peters L Ryom 《HIV medicine》2020,21(9):599-606
104.
105.
Toze CL Dalal CB Nevill TJ Gillan TL Abou Mourad YR Barnett MJ Broady RC Forrest DL Hogge DE Nantel SH Power MM Song KW Sutherland HJ Smith CA Narayanan S Young SS Connors JM Shepherd JD 《British journal of haematology》2012,158(2):174-185
The curative potential of allogeneic haematopoietic stem cell transplant (allo HSCT) in chronic lymphocytic leukaemia CLL is established, with a demonstrated role for graft-versus-leukaemia and less certainty for other factors in determining outcome. The first two decades of CLL patients proceeding to allo HSCT at the Leukaemia/Bone Marrow Transplant Program of British Columbia (n = 49 consecutive, 1991-2009) were studied to clarify factors predicting outcome. The donor was related in 29 (59%) and unrelated in 20 (41%). Conditioning was reduced-intensity in 27 (55%) and myeloablative in 22 (45%). Thirty-one of 49 patients survive with median follow-up of 5 years (0·2-15). Cumulative incidence of non-relapse mortality; complete remission (CR); clearance of fluorescence in situ hybridization (FISH) abnormality and progression at 10 years was 36%; 69%; 55% and 22%. Overall survival (OS) was 63% at 2 years; 55% at 5 years and beyond. Factors predicting OS (P value by log rank <0·05) were: comorbidity index <3, FISH rank (Dohner) and 17p deletion, alemtuzumab pre-HSCT, achievement of CR post-HSCT, donor chimerism >90%, clearance of FISH abnormality post-HSCT and absence of high-grade (3-4) graft-versus-host disease. Results from this province-wide, two-decade cohort demonstrated that a substantial proportion of patients with high-risk CLL become long term disease-free survivors. 相似文献
106.
Fiona?J?CharlsonEmail author Andrew?E?Moran Greg?Freedman Rosana?E?Norman Nicolas?JC?Stapelberg Amanda?J?Baxter Theo?Vos Harvey?A?Whiteford 《BMC medicine》2013,11(1):250
Background
Cardiovascular disease and mental health both hold enormous public health importance, both ranking highly in results of the recent Global Burden of Disease Study 2010 (GBD 2010). For the first time, the GBD 2010 has systematically and quantitatively assessed major depression as an independent risk factor for the development of ischemic heart disease (IHD) using comparative risk assessment methodology.Methods
A pooled relative risk (RR) was calculated from studies identified through a systematic review with strict inclusion criteria designed to provide evidence of independent risk factor status. Accepted case definitions of depression include diagnosis by a clinician or by non-clinician raters adhering to Diagnostic and Statistical Manual of Mental Disorders (DSM) or International Classification of Diseases (ICD) classifications. We therefore refer to the exposure in this paper as major depression as opposed to the DSM-IV category of major depressive disorder (MDD). The population attributable fraction (PAF) was calculated using the pooled RR estimate. Attributable burden was calculated by multiplying the PAF by the underlying burden of IHD estimated as part of GBD 2010.Results
The pooled relative risk of developing IHD in those with major depression was 1.56 (95% CI 1.30 to 1.87). Globally there were almost 4 million estimated IHD disability-adjusted life years (DALYs), which can be attributed to major depression in 2010; 3.5 million years of life lost and 250,000 years of life lived with a disability. These findings highlight a previously underestimated mortality component of the burden of major depression. As a proportion of overall IHD burden, 2.95% (95% CI 1.48 to 4.46%) of IHD DALYs were estimated to be attributable to MDD in 2010. Eastern Europe and North Africa/Middle East demonstrate the highest proportion with Asia Pacific, high income representing the lowest.Conclusions
The present work comprises the most robust systematic review of its kind to date. The key finding that major depression may be responsible for approximately 3% of global IHD DALYs warrants assessment for depression in patients at high risk of developing IHD or at risk of a repeat IHD event.107.
BO Motayo PA Akinduti FA Adeyakinu PO Okerentugba JC Nwanze CC Onoh HC Innocent-Adiele IO Okonko 《African health sciences》2013,13(4):1091-1097
Background
The increased reports of ESBL dissemination from various centres in south western, Nigeria and the recent emergence of carbapenem resistant bacteria prompted the conception of this study.Objectives
To demonstrate the relationship between high molecular weight plasmids and the expression of antibiotic multi-resistance including ESBL and carbapenemase.Methods
We investigated 97 isolates of selected organisms consisting of 67 E. coli and 30 Klebseilla spp for the presence of plasmids expressing ESBL including carbapenem-hydrolysing enzymes. Beta-lactamase was determined using acidometric method, while ESBL and carbapenemase activity was determined using the double-disk diffusion test as well as the Modified Hodge test (MHT). Plasmid profiles of ESBL and carbapenemase positive isolates were determined according to standard protocols.Results
An ESBL prevalence rate of 21.6% and carbapenem- resistance rate of 9.3% was recorded. Antibiotic susceptibility profile of ESBL isolates showed 100.0% resistance against Amoxicillin, Cotrimoxazole and Erythromycin. Moderate susceptibility was recorded against the Quinolone class of antibiotics; Meropenem remained the most active antibiotic against ESBL isolates with 62.5% against E. coli and 60% against K. pneumoniae. The plasmid profiles of our study isolates ranged from 11.8kbp to 35.5kbp.Conclusion
Due to the relationship between high molecular weight plasmids and multi-drug resistance, we hereby recommend regular molecular surveillance of this form in our study setting. 相似文献108.
BACKGROUND: Liver cirrhosis mortality differs by ethnicity in the United States. Some studies suggest alcohol sensitivity may contribute to this finding. This analysis evaluated if alcohol-associated changes in aspartate aminotransferase (AST) and alanine transaminase (ALT) differed by ethnicity among heavy drinkers. METHODS: Subjects included 1691 subjects from Project MATCH, a multicenter alcohol use disorders treatment trial. Changes in AST and ALT over 15 months were modeled as functions of ethnicity, age, gender, time, study site and alcohol use. The main focus was on ethnic differences in changes in transaminase activity occurring with changes in alcohol use. RESULTS: At all levels of alcohol consumption AST was lower in non-Hispanic whites relative to African Americans and Mexican Americans. Changes in AST associated with changes in alcohol use did not vary by ethnicity. ALT significantly differed only between Mexican Americans and non-Hispanic whites. Similar to AST, alcohol-associated ALT change did not differ by ethnicity. CONCLUSIONS: Among individuals with alcohol use disorders participating in a treatment trial, the effect of alcohol drinking on transaminase activity did not vary by ethnicity. However, in the general population, alcohol may still interact with other factors in mediating ethnic differences in cirrhosis mortality. 相似文献
109.
110.
Proportional hazard model estimation under dependent censoring using copulas and penalized likelihood 下载免费PDF全文
This paper considers Cox proportional hazard models estimation under informative right censored data using maximum penalized likelihood, where dependence between censoring and event times are modelled by a copula function and a roughness penalty function is used to restrain the baseline hazard as a smooth function. Since the baseline hazard is nonnegative, we propose a special algorithm where each iteration involves updating regression coefficients by the Newton algorithm and baseline hazard by the multiplicative iterative algorithm. The asymptotic properties for both regression coefficients and baseline hazard estimates are developed. The simulation study investigates the performance of our method and also compares it with an existing maximum likelihood method. We apply the proposed method to a dementia patients dataset. 相似文献