全文获取类型
收费全文 | 5569篇 |
免费 | 474篇 |
国内免费 | 72篇 |
专业分类
耳鼻咽喉 | 46篇 |
儿科学 | 139篇 |
妇产科学 | 91篇 |
基础医学 | 476篇 |
口腔科学 | 58篇 |
临床医学 | 652篇 |
内科学 | 1170篇 |
皮肤病学 | 29篇 |
神经病学 | 1084篇 |
特种医学 | 114篇 |
外科学 | 265篇 |
综合类 | 645篇 |
预防医学 | 431篇 |
眼科学 | 87篇 |
药学 | 479篇 |
11篇 | |
中国医学 | 241篇 |
肿瘤学 | 97篇 |
出版年
2024年 | 16篇 |
2023年 | 129篇 |
2022年 | 201篇 |
2021年 | 310篇 |
2020年 | 311篇 |
2019年 | 220篇 |
2018年 | 219篇 |
2017年 | 233篇 |
2016年 | 212篇 |
2015年 | 185篇 |
2014年 | 428篇 |
2013年 | 414篇 |
2012年 | 274篇 |
2011年 | 323篇 |
2010年 | 270篇 |
2009年 | 250篇 |
2008年 | 267篇 |
2007年 | 209篇 |
2006年 | 219篇 |
2005年 | 173篇 |
2004年 | 130篇 |
2003年 | 129篇 |
2002年 | 115篇 |
2001年 | 82篇 |
2000年 | 78篇 |
1999年 | 70篇 |
1998年 | 55篇 |
1997年 | 55篇 |
1996年 | 48篇 |
1995年 | 46篇 |
1994年 | 36篇 |
1993年 | 36篇 |
1992年 | 43篇 |
1991年 | 29篇 |
1990年 | 27篇 |
1989年 | 27篇 |
1988年 | 27篇 |
1987年 | 18篇 |
1986年 | 18篇 |
1985年 | 38篇 |
1984年 | 30篇 |
1983年 | 19篇 |
1982年 | 20篇 |
1981年 | 16篇 |
1980年 | 16篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1975年 | 5篇 |
1974年 | 6篇 |
排序方式: 共有6115条查询结果,搜索用时 15 毫秒
1.
2.
《Sleep medicine》2020
ObjectivesPrior evidence suggests that sleep duration and sleep difficulties may be associated with cognitive function in old age, but little is known about the sleep–cognition association in late mid-life. Our aim was to examine the associations of accelerometer-based sleep duration as well as subjective sleep difficulties with different domains of cognitive function among aging workers.MethodsThe study population consisted of 289 participants (mean age 62.4 years, SD 1.02; 83% women) from the Finnish Retirement and Aging Study (FIREA). Sleep difficulties were measured using Jenkins Sleep Problem Scale (difficulties falling asleep, difficulties maintaining sleep, waking up too early in the morning, and nonrestorative sleep). Sleep duration was measured with wrist-worn accelerometer and self-report, and participants were divided into short (<7 h/night), mid-range (7–9 h/night) and long (≥9 h/night) sleepers. Participants underwent extensive cognitive testing covering three domains: (1) memory, (2) executive function, and (3) attention and information processing.ResultsGreater difficulties in waking up too early in the morning were associated with poorer executive function measured with Spatial Working Memory (SWM) test (p = 0.005). Additionally, nonrestorative sleep was associated with poorer executive function measured with Trail Making Test, B–A, (p = 0.036) and borderline significantly with lower SWM (p = 0.056). Compared to mid-range sleepers, long sleepers tended to have poorer cognitive function (all memory function tests and SWM), but the associations were not statistically significant due to small number of long sleepers.ConclusionsSubjective sleep difficulties may be linked to poorer executive function in a relatively healthy population of older workers in their 60 s. Thus, promoting good sleep quality may translate into better cognitive health in late mid-life. 相似文献
3.
目的:探讨D6S1043、D12S391基因座的基因多态性对主动攻击行为的影响。方法:应用聚合酶链反应技术结合毛细管电泳法对114例男性主动攻击行为者(研究组)及120名健康男性(对照组)进行D6S1043、D12S391基因座的基因型及等位基因检测,分析D6S1043、D12S391基因座多态性与主动攻击行为的相关性。结果:研究组D6S1043基因座中12~19基因型频率(13.16%)明显高于对照组(1.67%)(P0.05);两组等位基因频率差异无统计学意义;两组D12S391基因座的基因型及等位基因频率差异无统计学意义。结论:D6S1043基因座中12~19基因型可能主动攻击行为有关。 相似文献
4.
ObjectivesTo explore the relationships among potentially modifiable factors related to childbirth and effective breastfeeding initiation at approximately 36 hours after birth and duration and exclusivity at hospital discharge, 2 weeks, 2 months, and 6 months after birth in primiparous women and to explore whether modifiable and nonmodifiable secondary factors and covariates influenced the relationships among factors related to childbirth and these breastfeeding outcomes.DesignA prospective, longitudinal, cohort study.SettingThe postpartum units of two general hospitals in eastern Canada.ParticipantsNinety-seven mother–infant dyads.MethodsWe recorded demographic, childbirth, obstetric history, and breastfeeding data through chart review. A breastfeeding observation was completed at approximately 36 hours after birth by unit nurses. Participants maintained breastfeeding logs in hospital and for 6 months after birth and completed three self-report questionnaires before discharge. We analyzed outcomes using backward stepwise linear and logistic regression.ResultsOne childbirth factor, labor induced with oxytocin, was negatively associated with effective initiation of breastfeeding, and none was related to breastfeeding duration and exclusivity at any time point. Maternal weight; professional support; and newborn’s gestational age at birth, 5-minute Apgar score, weight loss, LATCH score, and active feeds (newborn actively suckled at the breast) were significantly associated with breastfeeding outcomes.ConclusionInduction of labor with oxytocin should be used judiciously; when used, nurses must be hypervigilant to assess the mother–infant dyad for breastfeeding issues and to intervene to prevent or remediate them. 相似文献
5.
6.
7.
《Sleep medicine》2020
BackgroundTo date, no previous studies have evaluated the relationship between sleep duration and quality of life (QOL) or depression in the general population after controlling for daytime sleepiness and sleep disturbances.MethodsA web-based cross-sectional survey was conducted with 8698 subjects aged 20–69 years. We examined the relationships between weekday sleep duration and daytime sleepiness, sleep disturbance, QOL and depression, using the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index (without the item for sleep duration), 8-item Short Form and Center for Epidemiological Studies Depression Scale (CES-D).ResultsDaytime sleepiness tended to increase in proportion to shorter weekday sleep durations. Sleep disturbances, physical and mental QOL, and CES-D scores were worse in both the shorter and longer sleep groups compared with the group with 7–8 h of sleep. Hierarchical logistic regression analyses revealed that short sleep duration but not long sleep duration was significantly associated with reduction of both physical and mental QOL, even after controlling for the presence of daytime sleepiness and sleep disturbance. Both short and long sleep duration were independently and significantly correlated with depression after controlling for daytime sleepiness; however, there was no statistically significant association after adjusting for the effects of sleep disturbance.ConclusionsThe results suggested adverse effects of short sleep but not long sleep on both physical and mental QOL. In addition, the negative impact of specific types of sleep disturbance on depression may be greater than the impact of shortening of sleep duration. 相似文献
8.
Shinichiro Uchiyama Takao Hoshino Leila Sissani Monteiro Tavares Linsay Kenji Kamiyama Taizen Nakase Kazuo Kitagawa Kazuo Minematsu Kenichi Todo Yasushi Okada Jyoji Nakagawara Ken Nagata Hiroshi Yamagami Takenori Yamaguchi Pierre Amarenco 《Journal of stroke and cerebrovascular diseases》2019,28(8):2232-2241
BackgroundTIAregistry.org is an international cohort of patients with transient ischemic attack (TIA) or minor stroke within 7 days before enrollment in the registry. Main analyses of 1-year follow-up data have been reported.5 We conducted subanalysis on the baseline and 1-year follow-up data of Japanese patients.MethodsThe patients were classified into 2 groups based on Japanese ethnicity, Japanese (345) and non-Japanese (3238), and their baseline data and 1-year event rates were compared. We also determined risk factors and predictors of 1-year stroke.ResultsCurrent smoking, regular alcohol drinking, intracranial arterial stenosis, and small vessel occlusion; and hypertension, dyslipidemia, coronary artery disease, and extracranial arterial stenosis were more and less common among Japanese patients, respectively. Stroke risk was higher and TIA risk was lower at 1-year follow-up among Japanese patients. The baseline risk factors for recurrent stroke were diabetes, alcohol drinking, and large artery atherosclerosis. Independent predictors of 1-year stroke risk were prior congestive heart failure and alcohol consumption.ConclusionsThe two populations of patients featured differences in risk factors, stroke subtypes, and outcome events. Predictors of recurrent stroke among Japanese patients included congestive heart failure and regular alcohol drinking. Strategies to attenuate residual risk of stroke aside from adherence to current guidelines should take our Japanese-patient specific findings into account. 相似文献
9.
S. Aslanyan C. J. Weir C. S. Johnston M. Krams A. P. Grieve K. R. Lees 《European journal of neurology》2007,14(1):1-6
We sought to simultaneously confirm that substantial recovery at day 1 and day 7 after acute ischaemic stroke onset is associated with subsequent neurological deterioration in patients of the Acute Stroke Therapy by Inhibition of Neutrophils randomized clinical trial. Substantial recovery was assessed by improvement in the National Institutes of Health Stroke Score (NIHSS). Neurological deterioration was defined as any stroke event or NIHSS worsening from recovery assessment to day 90. After adjusting for age, t-PA and day 1 NIHSS, there was a non-significant tendency of substantial (pre-specified as 75%) recovery at day 1 to be associated with later deterioration [odds ratio (OR) 2.47; 95% CI, 0.95–6.50]. The corresponding OR for substantial (pre-defined as 65%) recovery at day 7 was 1.84 (0.85–3.96). Other thresholds for recovery were significantly associated with later deterioration: >50%, 80%, 90% and 100% for day 1 and >50%, 60%, 70%, 90% and 100% for day 7. The effect of recovery at day 1 was more important than that of later recovery. This study confirms the association between recovery and subsequent neurological deterioration and is the first to indicate the greater importance of acute recovery at day 1 in comparison with later recovery. 相似文献
10.
对102例海洛因依赖患者戒毒出院后操守时间及复吸原因进行分析,发现复吸原因主要与精神依赖及对精神依赖的错误认识等有关,用药维持治疗可明显操守时间.提出在戒毒出院后应采用象治疗神经症或精神病那样的方法来长期维持治疗。 相似文献