全文获取类型
收费全文 | 2885篇 |
免费 | 273篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 34篇 |
儿科学 | 154篇 |
妇产科学 | 49篇 |
基础医学 | 306篇 |
口腔科学 | 35篇 |
临床医学 | 251篇 |
内科学 | 652篇 |
皮肤病学 | 105篇 |
神经病学 | 293篇 |
特种医学 | 87篇 |
外国民族医学 | 1篇 |
外科学 | 528篇 |
综合类 | 85篇 |
一般理论 | 2篇 |
预防医学 | 208篇 |
眼科学 | 74篇 |
药学 | 131篇 |
中国医学 | 17篇 |
肿瘤学 | 156篇 |
出版年
2023年 | 19篇 |
2022年 | 41篇 |
2021年 | 88篇 |
2020年 | 40篇 |
2019年 | 74篇 |
2018年 | 89篇 |
2017年 | 69篇 |
2016年 | 69篇 |
2015年 | 68篇 |
2014年 | 115篇 |
2013年 | 143篇 |
2012年 | 210篇 |
2011年 | 185篇 |
2010年 | 94篇 |
2009年 | 121篇 |
2008年 | 143篇 |
2007年 | 165篇 |
2006年 | 134篇 |
2005年 | 132篇 |
2004年 | 115篇 |
2003年 | 95篇 |
2002年 | 81篇 |
2001年 | 82篇 |
2000年 | 89篇 |
1999年 | 70篇 |
1998年 | 40篇 |
1997年 | 55篇 |
1996年 | 35篇 |
1995年 | 27篇 |
1994年 | 38篇 |
1993年 | 34篇 |
1992年 | 43篇 |
1991年 | 29篇 |
1990年 | 46篇 |
1989年 | 39篇 |
1988年 | 30篇 |
1987年 | 19篇 |
1986年 | 20篇 |
1985年 | 17篇 |
1984年 | 19篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 11篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1973年 | 6篇 |
1952年 | 16篇 |
1951年 | 23篇 |
排序方式: 共有3168条查询结果,搜索用时 62 毫秒
11.
A female infant who presented with cyanosis and tachypnoea was found to have transposition of the great arteries, a ductus arteriosus, and a ventricular septal defect. An aortogram showed evidence of mild pulmonary regurgitation, which persisted after a Senning's operation; this is a hitherto unrecognised clinical finding. 相似文献
12.
B Qureshi 《Journal of the Royal Society of Medicine》1992,85(8):440-441
13.
14.
The prognostic impact of fluctuating levels of C-reactive protein in Brazilian haemodialysis patients: a prospective study. 总被引:5,自引:2,他引:3
Marcelo M Nascimento Roberto Pecoits-Filho A Rashid Qureshi Shirley Y Hayashi Roberto C Manfro Maria A Pachaly Luciana Renner Peter Stenvinkel Bengt Lindholm Miguel C Riella 《Nephrology, dialysis, transplantation》2004,19(11):2803-2809
BACKGROUND: A single elevated C-reactive protein (CRP) value predicts mortality in haemodialysis (HD) patients, but the relative importance of repeated vs occasional positive systemic inflammatory response findings is not known. METHODS: To assess the influence on survival of occasional inflammation, CRP, serum albumin (S-Alb) and fibrinogen were analysed bimonthly in 180 HD patients (54% male, 49+/-14 years). Clinically significant inflammation was defined as CRP >5.1 mg/l, based on the receiver operating characteristics curve for CRP as predictor of death. Based on four consecutive measurements of CRP, patients were assigned into three groups: group 1 (n = 74; 41%), no inflammation (CRP < or = 5.1 mg/l in all measurements); group 2 (n = 65; 36%), occasional inflammation (1-3 measurements of CRP > 5.1 mg/l); and group 3 (n = 41; 23%), persistent inflammation (all measurements of CRP >5.1 mg/l). The nutritional status was evaluated by subjective global assessment (SGA) and body mass index (BMI), and the survival (21 months of follow-up) by Kaplan-Meier curve and Cox model. RESULTS: The median and range of CRP values (mg/l) for group 1, 2 and 3 were: 3.2 (3.2-5.1), 3.6 (3.2-54.9) and 13.8 (5.2-82), respectively (P<0.001), whereas the prevalence of malnutrition, assessed by SGA and BMI, did not differ significantly between the groups. The survival rate by Kaplan-Meier analysis was significantly different among the groups (chi2 = 12.34; P = 0.0004). Patients in group 3 showed the highest mortality (34%; P = 0.001), compared with group 1 (8%) and group 2 (14%; P = 0.01), respectively, whereas there was no significant difference in mortality between groups 1 and 2. Age, CRP, S-Alb level and SGA were independent predictors of mortality. CONCLUSION: The patients with a persistent elevation of CRP had a higher mortality rate than the patients with occasional CRP elevation. Thus, persistent, rather than occasional, inflammation is an important predictor of death in HD patients. 相似文献
15.
Comparison of Asymmetry in Cerebral Blood Flow Between Brain Hemispheres Using Digital Subtraction Angiography 总被引:2,自引:0,他引:2
Afshin A. Divani PhD Adnan I. Qureshi MD Kenneth R. Hoffman PhD M. Fareed K. Suri MD Jawad F. Kirmani MD 《Journal of neuroimaging》2006,16(2):139-145
BACKGROUND AND PURPOSE: Recently, endovascular techniques have gained significant therapeutic potential for both treatment and prevention of stroke. Cerebral angiography, which is an essential component of these procedures, has been used to provide morphological information regarding condition of blood vessels. In this study, we propose to determine the possibility of acquiring information regarding cerebral blood flow (CBF) in addition to morphologic information from data routinely available during angiography. METHODS: Digital subtraction angiography sequences were obtained for eight patients having occlusive disease in internal carotid artery (ICA) territories. Two regions-of-interest (ROIs) corresponding to the two brain hemispheres on AP view were delineated. For each image, the average pixel value within each ROI was calculated and used to generate time-density curves. Indices obtained from each curve were compared with each other and with the results obtained from the single photon emission computed tomography (SPECT) studies performed a pre- or postangiography procedure. RESULTS: Comparison between ICA stenosis and cerebral perfusion measurements revealed that cerebral perfusion deficit can be independent of arterial occlusive disease. The indices obtained from the time-density curves exhibit a correlating trend with the results from SPECT studies. However, lack of sufficient sample data prevented any meaningful statistical analysis to be conducted. CONCLUSIONS: We have developed a technique for utilizing the angiographic data for the important task of routinely and easily measuring CBF. Availability of CBF measurements during cerebral angiography may favorably impact upon the appropriate use of endovascular procedures and potentially contribute to the reduction of morbidity and mortality associated with stroke. 相似文献
16.
R K Lamb S A Qureshi J L Wilkinson R Arnold C R West D I Hamilton 《The Journal of thoracic and cardiovascular surgery》1988,96(3):368-375
Between 1968 and 1985, 80 children underwent correction of total anomalous pulmonary venous drainage. There were 47 boys and 33 girls whose ages ranged from 3 days to 16 years (median 2 months, interquartile range 5 years). Seventy (87.5%) were less than 1 year of age at operation. Fifty-eight (72.5%) weighed less than 5 kg, the range being 1.6 to 42 kg (median 3.7 kg, interquartile range 2.4 kg). Forty-five (56%) patients had supracardiac, 14 (17.5%) cardiac, 15 (19%) infracardiac, and 6 (7.5%) had mixed total anomalous pulmonary venous drainage. Follow-up was complete in 78 (97.5%) and ranged from 6 to 189 months (median 58 months, interquartile range 59 months). There were 14 (17.5%) early and six (7.5%) late deaths. Analysis by various factors revealed year of operation as the only factor to affect survival at the 5% level of significance. Early mortality was 29% between 1968-1977 and 11% between 1978-1985 (p = 0.04). Postoperative pulmonary venous obstruction occurred in five (6%) patients between 6 weeks and 3 months after operation. All 5 died, three after reoperation. Five (6%) other children had reoperations, four for residual shunts and one for superior vena caval obstruction. 相似文献
17.
18.
Nazli Janjua MD Navin Verma MD Ammar Alkawi MD Jawad F. Kirmani MD Adnan I. Qureshi MD 《Journal of neuroimaging》2006,16(3):212-215
Endovascular stent-supported angioplasty is a treatment option for atherosclerotic disease of the cervical internal carotid artery in high-risk patients. The traditional transfemoral approach is not suitable for patients who suffer from common femoral artery or abdominal aorta atheropathy. We report a case of carotid stent deployment using the radial route in a 68-year-old man with type B aortic dissection, having severe right internal carotid artery origin stenosis, presenting with ipsilateral retinal ischemic events. Technical aspects of carotid stenting via the radial approach are described and the related literature is discussed. 相似文献
19.
20.
Paul C. Tang Mary Ralston Michelle Fernandez Arrigotti Lubna Qureshi Justin Graham 《J Am Med Inform Assoc》2007,14(1):10-15
New reimbursement policies and pay-for-performance programs to reward providers for producing better outcomes are proliferating. Although electronic health record (EHR) systems could provide essential clinical data upon which to base quality measures, most metrics in use were derived from administrative claims data. We compared commonly used quality measures calculated from administrative data to those derived from clinical data in an EHR based on a random sample of 125 charts of Medicare patients with diabetes. Using standard definitions based on administrative data (which require two visits with an encounter diagnosis of diabetes during the measurement period), only 75% of diabetics determined by manually reviewing the EHR (the gold standard) were identified. In contrast, 97% of diabetics were identified using coded information in the EHR.The discrepancies in identified patients resulted in statistically significant differences in the quality measures for frequency of HbA1c testing, control of blood pressure, frequency of testing for urine protein, and frequency of eye exams for diabetic patients. New development of standardized quality measures should shift from claims-based measures to clinically based measures that can be derived from coded information in an EHR. Using data from EHRs will also leverage their clinical content without adding burden to the care process. 相似文献