全文获取类型
收费全文 | 2703篇 |
免费 | 259篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 97篇 |
妇产科学 | 21篇 |
基础医学 | 343篇 |
口腔科学 | 39篇 |
临床医学 | 361篇 |
内科学 | 565篇 |
皮肤病学 | 27篇 |
神经病学 | 220篇 |
特种医学 | 193篇 |
外科学 | 263篇 |
综合类 | 44篇 |
预防医学 | 308篇 |
眼科学 | 28篇 |
药学 | 180篇 |
中国医学 | 10篇 |
肿瘤学 | 239篇 |
出版年
2021年 | 28篇 |
2020年 | 40篇 |
2019年 | 40篇 |
2018年 | 56篇 |
2017年 | 45篇 |
2016年 | 46篇 |
2015年 | 54篇 |
2014年 | 57篇 |
2013年 | 80篇 |
2012年 | 91篇 |
2011年 | 116篇 |
2010年 | 67篇 |
2009年 | 69篇 |
2008年 | 83篇 |
2007年 | 96篇 |
2006年 | 105篇 |
2005年 | 88篇 |
2004年 | 91篇 |
2003年 | 85篇 |
2002年 | 82篇 |
2001年 | 70篇 |
2000年 | 86篇 |
1999年 | 66篇 |
1998年 | 53篇 |
1997年 | 79篇 |
1996年 | 57篇 |
1995年 | 51篇 |
1994年 | 70篇 |
1993年 | 46篇 |
1992年 | 54篇 |
1991年 | 71篇 |
1990年 | 45篇 |
1989年 | 74篇 |
1988年 | 60篇 |
1987年 | 65篇 |
1986年 | 54篇 |
1985年 | 46篇 |
1984年 | 43篇 |
1983年 | 38篇 |
1982年 | 19篇 |
1981年 | 25篇 |
1980年 | 19篇 |
1979年 | 35篇 |
1978年 | 39篇 |
1977年 | 34篇 |
1976年 | 31篇 |
1975年 | 22篇 |
1973年 | 21篇 |
1972年 | 20篇 |
1969年 | 20篇 |
排序方式: 共有2973条查询结果,搜索用时 15 毫秒
1.
Well‐being,health and fitness of children who use wheelchairs: Feasibility study protocol to develop child‐centred ‘keep‐fit’ exercise interventions
下载免费PDF全文
![点击此处可从《Journal of advanced nursing》网站下载免费的PDF全文](/ch/ext_images/free.gif)
2.
Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography 总被引:2,自引:0,他引:2
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study. 相似文献
3.
An ecologically based examination of barriers to physical activity in students from grade seven through first-year university 总被引:1,自引:0,他引:1
Nancy C. Gyurcsik Ph.D. Kevin S. Spink Ph.D. Steven R. Bray Ph.D. Karen Chad Ph.D. Matt Kwan B.Sc. 《The Journal of adolescent health》2006,38(6):704-711
PurposeThe first purpose was to identify barriers to physical activity that students in grade seven through first-year university experienced. A second purpose was to classify barriers using an ecological framework and to examine the pattern of barrier categories (i.e., intrapersonal, interpersonal, institutional, community, public policy, and physical environmental) and specific barrier types as grade increased. The use of an ecological model addressed limitations in prior research revolving around the identification of salient barriers in a manner that makes the design of effective interventions difficult.MethodsParticipants in grades 7–8 (n = 35), 9–10 (n = 67), 11–12 (n = 80), and the freshmen year of university (n = 109) listed barriers to physical activity on an open-ended measure.ResultsFindings revealed a trend for the average number of barriers reported per student to increase as grade in school increased. First-year university students reported significantly more barriers than all other grade groupings. The frequency of barriers reported within the ecological categories was dependent on the specific grade groupings. Further, within each ecological category, distinct barriers were reported across the different grade groupings.ConclusionsFindings highlight the utility of using an ecological model to categorize barriers, rather than simply classifying barriers as internal or external to an individual, as done in prior research. Understanding the pattern of ecologically based barrier categories and specific types of barriers will help to inform the content of future research and interventions designed to alleviate salient barriers to physical activity. 相似文献
4.
R Litzenberger K M Morgan S F Marden K N Jacobs-Irvine S A Bray 《The Journal of cardiovascular nursing》1991,5(2):58-66
This case study illustrates the chronic nature of hyperlipidemia type IIa and the important contribution of the nurse in helping the client adjust life style, manage complex health regimes, and cope with the uncertainty of disease progression and its associated risks. 相似文献
5.
Paediatric dacryocystorhinostomy 总被引:1,自引:0,他引:1
KN Hakin FRCS FRCOphth TJ Sullivan FRACO FRACS A Sharma FCOphth † RAN Welham FRCS FCOphth † 《Clinical & experimental ophthalmology》1994,22(4):231-235
Of 258 cases of dacryocystorhinostomy performed on children in the period September 1981 to September 1991, 130 were for simple, unresolved congenital nasolacrimal duct obstruction. Other indications for surgery included punctal agenesis, lacrimal fistula, post-traumatic and post-inflammatory canalicular obstruction. Of 177 children without canalicular pathology, 171 (96%) were relieved of symptoms with one operation, without canalicular intubation. Of 81 cases with canalicular disease, 55 of 70 (79%) who underwent DCR plus canalicular intubation, and 10 of 11 who underwent DCR plus Lester-Jones tube, were substantially improved with one operation. No child required peroperative or postoperative blood transfusion. Dacryocystorhinostomy in childhood, in experienced surgical hands, is a safe procedure, achieving relief of symptoms in most cases, particularly in the absence of canalicular disease. 相似文献
6.
7.
Deborah Bray Preston Anthony R D'Augelli Cathy D Kassab Richard E Cain Frederick W Schulze Michael T Starks 《AIDS education and prevention》2004,16(4):291-303
Research investigating predictors of risky sexual behavior of rural MSM is sparse, even though the prevalence of HIV in rural areas has increased. This study explored two sets of predictors of 93 rural MSM's levels of risky sexual behavior: mental health variables and stigma emanating from men's family members, health care professionals, and people in the rural communities in which they live. Over 47% of the men were found to be at modified high to high risk. Logistic regression using a continuation logit model was used to test the relationship of the predictor variables and the four levels of risk. Findings indicate that self-esteem was predictive of the highest sexual risk behavior but not lower levels of risk. Stigma was predictive of modified high sexual risk when compared to low and no risk categories. No variables differentiated men at low risk from men at no risk. 相似文献
8.
9.
P P Vieyres J M de Bray J L Saumet F Patat L Pourcelot 《Journal of ultrasound in medicine》1994,13(11):887-893
A numerical model based on Navier-Stokes equations was used in conjunction with an experimental model in rabbits to study the effects of acute intracranial hypertension on basilar artery blood flow velocity. The hypertension was induced by pressure transmission via an epidural pressure sensor inserted into a parietal intracranial opening. A critical value of half of the diastolic arterial pressure for the intracranial cerebral pressure was determined by both numerical and experimental models. At this intracranial cerebral pressure level, the total input resistance and total input compliance, determined by the numerical model, exhibited an increase of 27% and 10%, respectively, and the tissular compliance a decrease of 25% from their physiologic baseline values. When the intracranial cerebral pressure reaches the level of the diastolic arterial pressure, a zero diastolic flow is observed into the cerebral vascular system. This study validates the theoretical model, which could be used in assessing intracranial cerebral pressure noninvasively in humans when O2 pressure can be stabilized. 相似文献