全文获取类型
收费全文 | 104540篇 |
免费 | 8574篇 |
国内免费 | 4768篇 |
专业分类
耳鼻咽喉 | 1471篇 |
儿科学 | 1352篇 |
妇产科学 | 1266篇 |
基础医学 | 13411篇 |
口腔科学 | 1950篇 |
临床医学 | 10877篇 |
内科学 | 16700篇 |
皮肤病学 | 2208篇 |
神经病学 | 5762篇 |
特种医学 | 5298篇 |
外国民族医学 | 21篇 |
外科学 | 11338篇 |
综合类 | 12843篇 |
现状与发展 | 28篇 |
一般理论 | 21篇 |
预防医学 | 6557篇 |
眼科学 | 3176篇 |
药学 | 10604篇 |
67篇 | |
中国医学 | 4139篇 |
肿瘤学 | 8793篇 |
出版年
2024年 | 212篇 |
2023年 | 1220篇 |
2022年 | 3021篇 |
2021年 | 4389篇 |
2020年 | 2975篇 |
2019年 | 2971篇 |
2018年 | 3313篇 |
2017年 | 2940篇 |
2016年 | 3282篇 |
2015年 | 4752篇 |
2014年 | 5889篇 |
2013年 | 5926篇 |
2012年 | 8765篇 |
2011年 | 9055篇 |
2010年 | 5834篇 |
2009年 | 5068篇 |
2008年 | 6471篇 |
2007年 | 6132篇 |
2006年 | 5735篇 |
2005年 | 5140篇 |
2004年 | 3940篇 |
2003年 | 3799篇 |
2002年 | 3142篇 |
2001年 | 2224篇 |
2000年 | 1925篇 |
1999年 | 1668篇 |
1998年 | 939篇 |
1997年 | 834篇 |
1996年 | 698篇 |
1995年 | 644篇 |
1994年 | 614篇 |
1993年 | 422篇 |
1992年 | 535篇 |
1991年 | 523篇 |
1990年 | 428篇 |
1989年 | 392篇 |
1988年 | 294篇 |
1987年 | 328篇 |
1986年 | 250篇 |
1985年 | 192篇 |
1984年 | 134篇 |
1983年 | 109篇 |
1982年 | 73篇 |
1981年 | 56篇 |
1980年 | 63篇 |
1979年 | 78篇 |
1975年 | 45篇 |
1974年 | 44篇 |
1973年 | 47篇 |
1972年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Comparative outcomes of vascular access in patients older than 70 years with end-stage renal disease
Deokbi Hwang Sujin Park Hyung-Kee Kim Seung Huh 《Journal of vascular surgery》2019,69(4):1196-1206.e5
Objective
The advantage of arteriovenous fistulas (AVFs) in older patients requiring dialysis is controversial. We reviewed our vascular access experience in patients ≥70 years of age (older group) compared with younger patients.Methods
We analyzed consecutive patients who underwent access surgery between 2013 and 2016. Primary success (PS) and primary patency (PP) data were analyzed between the older and younger groups before and after propensity score matching of the patients' characteristics and access composition. PS was defined as the achievement of access function that was amenable to two sessions of successful cannulation without early occlusion or maturation failure requiring revision. PP was defined as the time with uninterrupted patency without intervention.Results
A total of 594 consecutive accesses were created among 563 patients, of whom 119 were allocated into each group after propensity score matching. In the whole cohort, 193 accesses (32.5%) were performed in older patients. AVFs were performed in 130 (67.4%) older patients and 293 (73.1%) younger patients. Regarding AVFs, the PS rate (83.6% in the older group vs 94.3% in the younger group; P = .001) and the overall PP at 6 and 12 months (73.1% and 57.1%, respectively, in the older group vs 86.7% and 77.7%, respectively, in the younger group; P = .009) were lower in the older group than in the younger group. However, no differences were found in the PS and PP rates for arteriovenous grafts between groups. Regarding the AVF location, the PS rate for forearm AVFs was significantly lower in the older group than in the younger group (76% vs 93%; P < .001); however, the PS rate of the upper arm was not different between the groups (94% vs 97%; P = .425). In the patients with PS, the PP rate of AVFs was similar between the two groups. In the older group with forearm AVFs, the median diameter of the radial artery was larger in the patients with PS than in the patients without PS (2.20 mm with PS vs 2.00 mm without PS; P = .008). The propensity score matching results demonstrated similar trends for the whole cohort, with lower PS (P = .042) and PP rates (P = .023) for AVF in the older group.Conclusions
The outcomes after AVF were poorer in the older group than in the younger group, which was primarily due to unsatisfactory outcomes in patients with forearm AVFs. Thus, stricter criteria, especially regarding the radial artery diameter, should be applied for forearm AVFs in older patients, and additional research is necessary to delineate the risk factors for primary failure. 相似文献4.
5.
Fluid is usually restricted during thoracic surgery, and vasoactive agents are often administered to maintain blood pressure. One-lung ventilation (OLV) decreases arterial oxygenation; thus oxygen delivery to the brain can be decreased. In this study, we compared phenylephrine and dopamine with respect to maintaining cerebral oxygenation during OLV in major thoracic surgery.Sixty-three patients undergoing lobectomies were randomly assigned to the dopamine (D) or phenylephrine (P) group. The patients’ mean arterial pressure was maintained within 20% of baseline by a continuous infusion of dopamine or phenylephrine. Maintenance fluid was kept at 5 mL/kg/h. The depth of anesthesia was maintained with desflurane 1MAC and remifentanil infusion under bispectral index guidance. Regional cerebral oxygen saturation (rScO2) and hemodynamic variables were recorded using near-infrared spectroscopy and esophageal cardiac Doppler.The rScO2 was higher in the D group than the P group during OLV (OLV 60 min: 71 ± 6% vs 63 ± 12%; P = 0.03). The number of patients whose rScO2 dropped more than 20% from baseline was 0 and 6 in the D and P groups, respectively (P = 0.02). The D group showed higher cardiac output, but lower mean arterial pressure than the P group (4.7 ± 1.0 vs 3.9 ± 1.2 L/min; 76.7 ± 8.1 vs 84.5 ± 7.5 mm Hg; P = 0.02, P = 0.02). Among the variables, age, hemoglobin concentration, and cardiac output were associated with rScO2 by correlation analysis.Dopamine was superior to phenylephrine in maintaining cerebral oxygenation during OLV in thoracic surgery. 相似文献
6.
7.
Recent studies have reported an association between gastroesophageal reflux disease (GERD) and atrial fibrillation (AF). The objective of the present study was to evaluate whether AF is one of the risk factors for GERD occurrence.In this hospital-based, retrospective, case–control study, the patients were classified into 2 groups. The patients diagnosed with new AF were assigned to the AF group (n = 1612); those diagnosed without AF and GERD were assigned to the control group (n = 1612). The subjects in the control group were selected from outpatients of total healthcare center without a history of AF or GERD, and matched for age and gender. We evaluated the incidence of GERD and risk factors for GERD occurrence between the 2 groups.The number of patients experiencing occurrence of GERD during the follow-up period was significantly higher in the AF group than those in the control group, respectively (129 patients vs 98 subjects, P = 0.037). The incidence of GERD was significantly higher in the AF group than in the control group by Kaplan–Meier analysis with log-rank test (P = 0.008). The AF group''s adjusted hazard ratio of GERD occurrence against that of the control group was 1.37 (95% confidence interval [CI]: 1.16–1.57; P = 0.009) according to Cox''s proportional hazard model.The presence of AF appears to increase the incidence of GERD and may be considered a risk factor for the development of GERD. Further, large prospective and cohort studies will be required to better establish the correlation of GERD with AF. 相似文献
8.
9.
10.