全文获取类型
收费全文 | 1580篇 |
免费 | 169篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 57篇 |
妇产科学 | 18篇 |
基础医学 | 237篇 |
口腔科学 | 24篇 |
临床医学 | 194篇 |
内科学 | 443篇 |
皮肤病学 | 18篇 |
神经病学 | 90篇 |
特种医学 | 53篇 |
外科学 | 179篇 |
综合类 | 44篇 |
预防医学 | 113篇 |
眼科学 | 147篇 |
药学 | 90篇 |
肿瘤学 | 58篇 |
出版年
2021年 | 31篇 |
2020年 | 17篇 |
2019年 | 16篇 |
2018年 | 19篇 |
2016年 | 16篇 |
2015年 | 36篇 |
2014年 | 40篇 |
2013年 | 52篇 |
2012年 | 53篇 |
2011年 | 62篇 |
2010年 | 56篇 |
2009年 | 42篇 |
2008年 | 45篇 |
2007年 | 80篇 |
2006年 | 49篇 |
2005年 | 49篇 |
2004年 | 47篇 |
2003年 | 31篇 |
2002年 | 27篇 |
2001年 | 53篇 |
2000年 | 32篇 |
1999年 | 36篇 |
1998年 | 37篇 |
1997年 | 26篇 |
1996年 | 38篇 |
1995年 | 15篇 |
1994年 | 16篇 |
1993年 | 25篇 |
1992年 | 27篇 |
1991年 | 30篇 |
1990年 | 25篇 |
1989年 | 32篇 |
1988年 | 34篇 |
1987年 | 36篇 |
1986年 | 30篇 |
1985年 | 35篇 |
1984年 | 30篇 |
1983年 | 25篇 |
1981年 | 16篇 |
1978年 | 22篇 |
1976年 | 17篇 |
1975年 | 20篇 |
1974年 | 14篇 |
1973年 | 14篇 |
1970年 | 16篇 |
1959年 | 17篇 |
1958年 | 16篇 |
1957年 | 14篇 |
1955年 | 15篇 |
1954年 | 19篇 |
排序方式: 共有1768条查询结果,搜索用时 15 毫秒
91.
Sears SF Serber ER Alvarez LG Schwartzman DS Hoyt RH Ujhelyi MR 《Pacing and clinical electrophysiology : PACE》2005,28(8):801-807
BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with a variety of symptoms such as dizziness, palpitations, shortness of breath, and other signs of heart failure, which in turn impact quality of life (QOL). Implantable cardioverter defibrillators with atrial therapies (ICDs-ATs) have been shown to reduce AF symptoms and improve QOL in select AF samples. METHOD: This study examined the strength of relationships between objective (device-detected AF events) versus subjective (emotional symptoms) data and AF symptoms (number) reported as part of the Patient Atrial Shock Survey of Acceptance and Tolerance Study (N = 96, 72% men, M age = 65, SD = 12). Depression and anxiety were assessed via the Center for Epidemiological Studies--Depression Scale and the-State Trait Anxiety Inventory. AF disease burden was measured via a number of device-detected AF episodes and the Atrial Tachyarrhythmia Symptom Severity Scale. RESULTS: Hierarchical multiple regression analysis indicated that negative emotions accounted for a significant 13.2% of unique variance in AF symptom score (F change (1, 54) = 9.625, P = 0.003). On the other hand, the number of device-detected AF episodes accounted for non-significant 8.2% of unique variance in the AF symptom score (P = 0.167). The full model explained 25.7% of the variance in AF symptom score (F(6, 54) = 3.110, P = 0.011). Specifically, greater number of treated AF episodes (beta= 0.251, P = 0.043) and higher levels of negative emotions (beta= 0.369, P = 0.003) predicted greater number of reported AF symptoms. CONCLUSION: Therefore, psychological distress may be a significant confounding factor affecting patient's report of AF symptoms rather than the actual experience of recurrent AF episodes. 相似文献
92.
INTRODUCTION: Patient acceptance of implantable device therapy has been established as an important outcome but the operationalization and validation of a measure of patient acceptance of implantable device therapy has not been fully completed. This study sought to validate a new measure of patient acceptance of cardiac implantable devices called the Florida Patient Acceptance Survey (FPAS). METHODS: The sample consisted of implantable cardioverter defibrillator (ICD; n = 58), and implantable atrioverter defibrillator (ICD-AT; n = 96), and pacemaker (PM, n = 84) patients. Mean age of all participants was 69 years; they were mostly male (62%) and married (75%). The final FPAS comprised 15 items with four consistent factors: Return to Function, Device-Related Distress, Positive Appraisal, and Body Image Concerns. RESULTS: The total FPAS demonstrated good internal consistency (Cronbach's alpha = 0.83), and internal consistency for each of the subscales ranged from 0.74 to 0.89. The FPAS demonstrated convergent, divergent, and discriminant validity when compared to other self-report measures of QOL, atrial symptoms, depression, and anxiety. A total FPAS score can be formed and between group comparisons with this sample indicated that ICD patients report a high level of acceptance (mean = 76), ICD-AT patients report a significantly higher level of acceptance (mean = 81.1), and PM patients reported the highest level of patient acceptance (mean = 85.4) of these implantable device groups. CONCLUSION: This initial psychometric investigation of the FPAS suggests that the FPAS may be useful in both clinical and research settings to assess patient acceptance of implantable cardiac devices. 相似文献
93.
Mandhane PJ Greene JM Cowan JO Taylor DR Sears MR 《American journal of respiratory and critical care medicine》2005,172(1):45-54
RATIONALE: Factors predicting the development of wheeze may differ between sexes and between childhood and adolescence. METHODS: A New Zealand birth cohort of 1,037 children was followed to age 26. For this analysis, those reporting recurrent wheezing at two or more assessments were classified as "wheezers." We examined risk factors for development of wheeze before age 10 (childhood) and subsequently (adolescent-onset) for males and for females separately using Cox regression modeling. RESULTS: Males more often developed childhood wheeze (p = 0.002) and females adolescent-onset wheeze (p < 0.001). Maternal atopy (asthma or hay fever) was a risk factor for childhood wheeze in both sexes (hazard ratio [HR], 1.48, p < 0.05 for males; HR, 2.37, p < 0.001 for females). Paternal atopy also influenced childhood wheeze, significantly for males (HR, 1.72; p = 0.01), and similarly but not significantly for females (HR, 1.70; p = 0.08). For adolescent-onset wheeze, neither maternal (HR, 1.41; p = 0.19) nor paternal history (HR, 0.73; p = 0.42) was a risk factor in males, but maternal history (HR, 2.08; p < 0.01) was a significant risk factor for females. When both age ranges were combined, providing greater power for analysis, paternal history was a stronger risk factor for wheeze in females (HR, 1.62; p = 0.02) than in males (HR, 1.35; p = 0.12). CONCLUSION: The influence of parental atopy on the development for wheeze differs between males and females and between childhood- and adolescent-onset wheeze. 相似文献
94.
Technique for iridocyclectomy 总被引:1,自引:0,他引:1
M L Sears 《American journal of ophthalmology》1968,66(1):42-44
95.
96.
Efferent discharges in alpha and fusimotor fibres of intercostal nerves of the cat 总被引:10,自引:7,他引:3 下载免费PDF全文
T. A. Sears 《The Journal of physiology》1964,174(2):295-315
97.
98.
Previous studies have shown that the Shaker Exercise is effective in restoring oral intake in patients with deglutitive failure due to upper esophageal sphincter (UES) dysfunction. Our aim was to determine (1) exerciser compliance among healthy older adults, (2) number of days required to attain the isometric (IM) and isokinetic (IK) exercise goals, (3) rate and reason for dropout of exercisers, and (4) complaints associated with performance of the exercise. Twenty-six nondysphagic older adults were enrolled from an independent-living community (66–93 yr) to perform the Shaker Exercise. Each participant completed a questionnaire on exercise performance and its associated difficulties three times a day for six weeks. Four randomly chosen nondysphagic participants underwent pre- and postexercise videofluoroscopic swallow studies for biomechanical measurements. Maximum anterior hyoid and laryngeal excursions, as well as maximum anteroposterior UES opening increased (p < 0.05) following exercise. Duration to attain Shaker Exercise performance goals varied among participants. IK was more easily attained than IM. Only 50% and 70% of those enrolled initially were able to complete the exercise duration and attain its IK and IM goals, respectively. However, those who stayed in the program attained the IK and IM goals (100% and 74%, respectively). Most dropouts occurred in the first two weeks of exercise. Performance of the exercise was associated with mild muscle discomfort that resolved spontaneously after a couple of weeks. We concluded that although the Shaker Exercise can be performed independently, a structured and gradually progressive program is needed to attain the exercise goals completely.Supported in part by a grant from Retirement Research Foundation. 相似文献
99.
Chronic exposure to air pollution is associated with increased mortality rates. The impact of air pollution relative to other causes of death in a population is of public health importance and has not been well established. In this study, the rate advancement periods associated with traffic pollution exposures were estimated. Study subjects underwent pulmonary function testing at a clinic in Hamilton, Ontario, Canada, between 1985 and 1999. Cox regression was used to model mortality from all natural causes during 1992-2001 in relation to lung function, body mass index, a diagnosis of chronic pulmonary disease, chronic ischemic heart disease, or diabetes mellitus, household income, and residence within 50 m of a major urban road or within 100 m of a highway. Subjects living close to a major road had an increased risk of mortality (relative risk = 1.18, 95% confidence interval: 1.02, 1.38). The mortality rate advancement period associated with residence near a major road was 2.5 years (95% confidence interval: 0.2, 4.8). By comparison, the rate advancement periods attributable to chronic pulmonary disease, chronic ischemic heart disease, and diabetes were 3.4 years, 3.1 years, and 4.4 years, respectively. 相似文献
100.
Al-Khayer K Hagstrom S Pauer G Zegarra H Sears J Traboulsi EI 《American journal of ophthalmology》2004,137(2):375-377
PURPOSE: To present long-term follow-up on a North American patient with Leber congenital amaurosis (LCA) and novel compound heterozygous mutations in the RPE65 gene. DESIGN: Case report. METHODS: RPE65 mutation screening and search for sequence changes using Single Strand Conformation Polymorphism and direct DNA sequencing. Ophthalmic examination and electrophysiologic testing. RESULTS: A 35-year-old female carried two RPE65 mutations: a maternal 961A>T (K303X) nonsense mutation and a paternal 1346A>G (Y431C) missense mutation. She had severe visual deficits and an absence of rod and cone Electroretinogram responses. Visual acuity of 20/60 both eyes and normal color recognition during early childhood declined to 2/200 in the right eye and 1/200 in the left eye at the age of 35. CONCLUSIONS: The RPE65 mutations K303X and Y431C in compound heterozygous form cause progressive visual compromise that starts in childhood and advances to severe visual loss by the fourth decade of life. 相似文献