全文获取类型
收费全文 | 4806篇 |
免费 | 282篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 139篇 |
妇产科学 | 115篇 |
基础医学 | 756篇 |
口腔科学 | 74篇 |
临床医学 | 470篇 |
内科学 | 941篇 |
皮肤病学 | 223篇 |
神经病学 | 576篇 |
特种医学 | 157篇 |
外科学 | 382篇 |
综合类 | 19篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 472篇 |
眼科学 | 77篇 |
药学 | 274篇 |
中国医学 | 17篇 |
肿瘤学 | 386篇 |
出版年
2024年 | 10篇 |
2023年 | 42篇 |
2022年 | 87篇 |
2021年 | 157篇 |
2020年 | 101篇 |
2019年 | 146篇 |
2018年 | 155篇 |
2017年 | 105篇 |
2016年 | 143篇 |
2015年 | 141篇 |
2014年 | 216篇 |
2013年 | 262篇 |
2012年 | 387篇 |
2011年 | 392篇 |
2010年 | 233篇 |
2009年 | 207篇 |
2008年 | 297篇 |
2007年 | 297篇 |
2006年 | 316篇 |
2005年 | 302篇 |
2004年 | 260篇 |
2003年 | 216篇 |
2002年 | 179篇 |
2001年 | 30篇 |
2000年 | 25篇 |
1999年 | 29篇 |
1998年 | 33篇 |
1997年 | 23篇 |
1996年 | 29篇 |
1995年 | 22篇 |
1994年 | 18篇 |
1993年 | 12篇 |
1992年 | 13篇 |
1991年 | 13篇 |
1990年 | 14篇 |
1989年 | 8篇 |
1988年 | 14篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 16篇 |
1984年 | 17篇 |
1983年 | 7篇 |
1981年 | 10篇 |
1977年 | 10篇 |
1975年 | 7篇 |
1974年 | 7篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1971年 | 9篇 |
1968年 | 7篇 |
排序方式: 共有5107条查询结果,搜索用时 0 毫秒
951.
Eyal Klang Dvora Aharoni Kay-Geert Hermann Amir Herman Uri Rimon Nachshon Shazar Iris Eshed 《Skeletal radiology》2014,43(4):499-505
Objective
To assess the contribution of contrast material in detecting and evaluating enthesitis of pelvic entheses by MRI.Materials and methods
Sixty-seven hip or pelvic 1.5-T MRIs (30:37 male:female, mean age: 53 years) were retrospectively evaluated for the presence of hamstring and gluteus medius (GM) enthesitis by two readers (a resident and an experienced radiologist). Short tau inversion recovery (STIR) and T1-weighted pre- and post-contrast (T1+Gd) images were evaluated by each reader at two sessions. A consensus reading of two senior radiologists was regarded as the gold standard. Clinical data was retrieved from patients’ referral form and medical files. Cohen’s kappa was used for intra- and inter-observer agreement calculation. Diagnostic properties were calculated against the gold standard reading.Results
A total of 228 entheses were evaluated. Gold standard analysis diagnosed 83 (36 %) enthesitis lesions. Intra-reader reliability for the experienced reader was significantly (p?=?0.0001) higher in the T1+Gd images compared to the STIR images (hamstring: k?=?0.84/0.45, GM: k?=?0.84/0.47). Sensitivity and specificity increased from 0.74/0.8 to 0.87/0.9 in the STIR images and T1+Gd sequences. Intra-reader reliability for the inexperienced reader was lower (p?>?0.05).Conclusions
Evidence showing that contrast material improves the reliability, sensitivity, and specificity of detecting enthesitis supports its use in this setting. 相似文献952.
953.
954.
955.
OBJECTIVE: To identify risk and protective factors for violence perpetration among youth with a history of grade retention. DESIGN: Longitudinal analysis of in-home interviews of 13,781 adolescents in grades 7 through 12 conducted in 1995 and 1996. METHODS AND MEASURES: Serious interpersonal violence perpetration at time 2 by time 1 independent variables including measures of community and school context, family context, and individual characteristics. RESULTS: The 20% of girls and 28% of boys who had repeated 1 or more grades were more likely than those who had not to be in the top quintile of violence perpetration at time 2 (P <.001). For both girls and boys with a history of grade repetition, predictive risk factors with an odds ratio of 3 or greater (P <.001) included time 1 violence perpetration, violence victimization, weapon carrying, school problems, and alcohol and marijuana use. Although a high grade point average was a significant protective factor against violence perpetration for both girls (odds ratio, 0.36; P <.05) and boys (odds ratio, 0.23; P <.001), performance on a validated measure of verbal knowledge was not associated with violence perpetration over the study period. School connectedness, parent-family connectedness, and emotional well-being were also significant universal protectors against violence perpetration. CONCLUSIONS: Youth who are held back in school are at heightened risk for violence perpetration. Violence-related behaviors and substance use considerably increase the likelihood of this outcome. The findings suggest that schools can participate in violence prevention by providing youth with a positive community and academic experience. 相似文献
956.
Gomes Iris Rafaela Leão Nascimento Eduarda Helena Leandro Gaêta-Araujo Hugo Anjos Pontual Maria Luiza Ramos-Perez Flávia Maria Moraes dos Anjos Pontual Andrea 《Oral Radiology》2022,38(3):356-362
Oral Radiology - To investigate the performance of radiographic systems with automatic exposure compensation (AEC) on the caries diagnosis in images acquired with different exposure parameters and... 相似文献
957.
Niu John Yun Yin Iris Xiaoxue Wu William Ka Kei Li Quan-Li Mei May Lei Chu Chun Hung 《Clinical oral investigations》2022,26(3):2441-2451
Clinical Oral Investigations - To investigate the antibiofilm and remineralising effects of the dual-action peptide GA-KR12 on artificial enamel caries. Enamel blocks with artificial caries were... 相似文献
958.
Ribak R Harlev A Ohel I Sergienko R Wiznitzer A Sheiner E 《European journal of obstetrics, gynecology, and reproductive biology》2011,158(1):33-36
Objective
To assess pregnancy outcome in women who initially refused medically indicated caesarean delivery (CD) in cases of non-reassuring fetal heart rate (FHR) patterns.Study design
A retrospective cohort study, comparing patients who refused and did not refuse caesarean delivery (CD) due to non-reassuring FHR tracings, was conducted. Deliveries occurred between the years 1988 and 2009 in a tertiary medical center. Multivariate analysis was performed to control for confounders.Results
Out of 10,944 women who were advised to undergo CD due to non-reassuring FHR patterns, 203 women initially refused CD. Women refusing medical intervention tended to be older (30.6 ± 6.9 vs. 28.29 ± 6.1, P < 0.001) and of higher parity (46.8% vs. 19.9% had more than 5 deliveries; P < 0.001) as compared to the comparison group. Refusal of CD was significantly associated with adverse perinatal outcome. Using a multiple logistic regression model controlling for confounders such as maternal age, refusal of treatment was found as an independent risk factor for perinatal mortality (adjusted OR = 3.3, C.I. 95% 1.8-5.9, P < 0.001). A non-significant trend towards higher rates of adverse perinatal outcome was found when refusal latency time was longer than 20 min (OR = 2, 95% CI 0.36-11.95; P = 0.29).Conclusion
Refusal of CD in cases of non-reassuring FHR tracings is an independent risk factor for perinatal mortality. 相似文献959.
960.
Makkes S Montenegro-Bethancourt G Groeneveld IF Doak CM Solomons NW 《Maternal & child nutrition》2011,7(4):410-420
This analysis explores the clustering of beverage patterns in a single day in private vs. public school children in urban Guatemala. This study is based on measurements taken from 356 third- and fourth-grade pupils from the highland city of Quetzaltenango. Height, weight and body mass index were assessed, and one day's intake of all foods and beverages using a pictorial workbook and dietician assisted recall. Mean differences in beverage consumption were compared for private vs. public school children and by anthropometric outcomes (stunting, overweight and obesity). Plain water was consumed by 30.9% of the children on the day intakes were measured, with higher proportions of water drinkers among private school children. Children having reported water intake on that day consumed 154 fewer kcal (-7.7%) compared with the energy intake of children not having reported water intake (P = 0.02). Significantly more children of high socio-economic status (SES) consumed dairy, fruit juice, commercial fruit juice, fruit drink and soda whereas low SES children consumed thin gruels and infusions. A key result from this study is the finding of a lower energy intake shown by children reporting water intake. 相似文献