全文获取类型
收费全文 | 1992篇 |
免费 | 114篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 73篇 |
妇产科学 | 61篇 |
基础医学 | 239篇 |
口腔科学 | 6篇 |
临床医学 | 329篇 |
内科学 | 257篇 |
皮肤病学 | 18篇 |
神经病学 | 220篇 |
特种医学 | 55篇 |
外科学 | 178篇 |
综合类 | 11篇 |
预防医学 | 246篇 |
眼科学 | 110篇 |
药学 | 104篇 |
中国医学 | 1篇 |
肿瘤学 | 157篇 |
出版年
2023年 | 12篇 |
2022年 | 15篇 |
2021年 | 37篇 |
2020年 | 27篇 |
2019年 | 44篇 |
2018年 | 47篇 |
2017年 | 47篇 |
2016年 | 35篇 |
2015年 | 49篇 |
2014年 | 60篇 |
2013年 | 92篇 |
2012年 | 167篇 |
2011年 | 166篇 |
2010年 | 88篇 |
2009年 | 62篇 |
2008年 | 128篇 |
2007年 | 146篇 |
2006年 | 145篇 |
2005年 | 121篇 |
2004年 | 101篇 |
2003年 | 97篇 |
2002年 | 97篇 |
2001年 | 25篇 |
2000年 | 16篇 |
1999年 | 26篇 |
1998年 | 19篇 |
1997年 | 11篇 |
1996年 | 18篇 |
1995年 | 15篇 |
1994年 | 7篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 13篇 |
1987年 | 9篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 12篇 |
1977年 | 10篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1971年 | 3篇 |
1968年 | 4篇 |
排序方式: 共有2110条查询结果,搜索用时 15 毫秒
101.
Nair N Oka RK Waring LD Umoh EM Taylor CB Cooke JP 《Vascular medicine (London, England)》2005,10(4):275-283
Cardiovascular risk factors are associated with impaired endothelium dependent vasodilation and reduced vascular compliance. In this study, the correlation with cardiovascular risk factor score of two common techniques for assessing vascular function was compared. Risk factors and vascular function were evaluated in a study population of 122 people with peripheral arterial disease (PAD) or with risk factors for PAD (73 men and 49 women; mean age 69 years). A risk factor score was determined using Framingham criteria. Vascular compliance was assessed by pulse waveform analysis and simultaneous blood pressure measurement. Flow-mediated vasodilation of the brachial artery was measured using duplex ultrasonography. Participants with a high risk factor score had significantly reduced vascular compliance of large and small vessels. By contrast, the difference in flow-mediated vasodilation between those with a high or low risk factor score did not reach statistical significance. There was a significant negative correlation between vascular compliance and risk factor score. There was a similar trend between flow-mediated vasodilation and risk factor score, but this did not reach statistical significance. A measure of vascular compliance was more significantly correlated with cardiovascular risk factor score than was a measure of flow-mediated vasodilation in the study population. Neither technique provided values that were highly correlated with risk factor burden. Although flow-mediated vasodilation is a preferred research tool for assessing vascular function, technical limitations and biological variability may reduce its clinical application in assessing individual cardiovascular risk. 相似文献
102.
103.
104.
On February 2, 2004, the Food and Drug Administration organized a joint meeting of the Neuro-Psychopharmacologic Advisory Committee and Pediatric Subcommittee of the Anti-Infective Drugs Advisory Committee to examine the occurrence of suicidality in clinical trials that investigate the use of the newer antidepressant drugs in pediatric patients. Committee members reconvened on September 13-14, 2004, and concluded that there was a causal link between the newer antidepressants and pediatric suicidality. This article provides a summary of the Food and Drug Administration deliberations for the pediatric clinician. We also provide research, regulation, education, and practice implications for care for children and adolescents who may be eligible for treatment with these medications. 相似文献
105.
The label "learning disabilities" is all-embracing; it describes a syndrome, not a specific child with specific problems. Parent involvement in and collaboration with pediatricians and schools in navigating service systems, accessing appropriate services, and case management are particularly relevant for children with LD. Comprehensive service delivery in school settings requires the interface of other service sectors, such as primary care, mental health,and other community agencies that also recognize and address children's problems. To date, marked differences exist among the assessment, classification and diagnostic, and treatment practices of these service systems, despite the fact that they address the same patient population--school-aged youth. Additionally, many of these agencies and systems operate in isolation with limited cross-sector communication or service collaboration. Parent involvement and advocacy, with assistance from pediatricians and knowledgeable school personnel, is necessary to ensure that appropriate resources available from these sectors are well coordinated and provided for children with an LD to improve their school performance and ongoing educational experience. 相似文献
106.
Weckerly J Aarons GA Leslie LK Garland AF Landsverk J Hough RL 《Journal of developmental and behavioral pediatrics : JDBP》2005,26(3):201-208
The impact of caregiver education level on endorsement of attention-deficit hyperactivity disorder (ADHD) symptoms for inattention (IA) and hyperactivity-compulsivity (HA) in a sample of high-risk youths was examined. Participants were 1347 caregivers of varying educational backgrounds who completed the ADHD module of the Diagnostic Interview Schedule for Children IV. The relationship of caregiver education to ADHD symptom endorsement was examined in three sets of analyses in which IA and HA symptoms were simultaneously regressed on caregiver years of education. Both multivariate analysis of covariance and logistic regression analyses revealed significantly lower rates of IA symptom endorsement by caregivers with less education, while there was no effect for HA symptoms. A multiple indicator multiple cause (MIMIC) model analysis also revealed that caregiver years of education was significantly positively associated with IA but not with HA symptoms, even when other demographic factors were controlled. There is a clear effect of caregiver education on ADHD symptom endorsement patterns, raising concerns that demographic factors related to symptom measurement may contribute to discrepancies in the assessment and treatment of ADHD. 相似文献
107.
108.
DeRubeis RJ Hollon SD Amsterdam JD Shelton RC Young PR Salomon RM O'Reardon JP Lovett ML Gladis MM Brown LL Gallop R 《Archives of general psychiatry》2005,62(4):409-416
BACKGROUND: There is substantial evidence that antidepressant medications treat moderate to severe depression effectively, but there is less data on cognitive therapy's effects in this population. OBJECTIVE: To compare the efficacy in moderate to severe depression of antidepressant medications with cognitive therapy in a placebo-controlled trial. DESIGN: Random assignment to one of the following: 16 weeks of medications (n = 120), 16 weeks of cognitive therapy (n = 60), or 8 weeks of pill placebo (n = 60). SETTING: Research clinics at the University of Pennsylvania, Philadelphia, and Vanderbilt University, Nashville, Tenn. PATIENTS: Two hundred forty outpatients, aged 18 to 70 years, with moderate to severe major depressive disorder. INTERVENTIONS: Some study subjects received paroxetine, up to 50 mg daily, augmented by lithium carbonate or desipramine hydrochloride if necessary; others received individual cognitive therapy. MAIN OUTCOME MEASURE: The Hamilton Depression Rating Scale provided continuous severity scores and allowed for designations of response and remission. RESULTS: At 8 weeks, response rates in medications (50%) and cognitive therapy (43%) groups were both superior to the placebo (25%) group. Analyses based on continuous scores at 8 weeks indicated an advantage for each of the active treatments over placebo, each with a medium effect size. The advantage was significant for medication relative to placebo, and at the level of a nonsignificant trend for cognitive therapy relative to placebo. At 16 weeks, response rates were 58% in each of the active conditions; remission rates were 46% for medication, 40% for cognitive therapy. Follow-up tests of a site x treatment interaction indicated a significant difference only at Vanderbilt University, where medications were superior to cognitive therapy. Site differences in patient characteristics and in the relative experience levels of the cognitive therapists each appear to have contributed to this interaction. CONCLUSION: Cognitive therapy can be as effective as medications for the initial treatment of moderate to severe major depression, but this degree of effectiveness may depend on a high level of therapist experience or expertise. 相似文献
109.
Motor imagery (MI) has been associated with planning stages of motor production, and in particular, with internal models that predict the sensory consequences of motor commands and specify the motor commands required to achieve a given outcome. In this study we investigated several predictions derived from the hypothesis that ideomotor apraxia (IM), a deficit in pantomime and imitation of skilled actions, may be attributable in part to deficits in internal models for planning object-related actions, in the face of relatively intact on-line, feedback-driven control of action. This hypothesis predicts that in IM, motor imagery should be (a) strongly correlated with other motor tasks not providing strong visual, tactile, and proprioceptive feedback from objects, i.e., object-related pantomime and imitation; (b) poorly correlated with performance tasks providing strong environmental feedback about the locations of effectors and targets, i.e., actual interaction with objects; and (c) particularly deficient in conditions that are computationally difficult for the motor planning system. Eight left fronto-parietal stroke patients with IM, five stroke patients without IM, and six healthy matched controls imagined grasping dowels and widgets presented at varying orientations, and actually grasped the same objects. The experimental predictions were confirmed. In addition, patients with IM and motor imagery deficits were significantly more likely than the non-apraxic group to have lesions in the intraparietal sulcus, a region previously implicated in imagery for hand-object interactions. The findings suggest a principled explanation for the deficits of IM patients in object-related gesture pantomime, imitation, and learning of new object-related gestures. 相似文献
110.