全文获取类型
收费全文 | 34223篇 |
免费 | 2425篇 |
国内免费 | 55篇 |
学科分类
医药卫生 | 36703篇 |
出版年
2024年 | 44篇 |
2023年 | 302篇 |
2022年 | 526篇 |
2021年 | 1135篇 |
2020年 | 690篇 |
2019年 | 1049篇 |
2018年 | 1173篇 |
2017年 | 845篇 |
2016年 | 990篇 |
2015年 | 1039篇 |
2014年 | 1364篇 |
2013年 | 1917篇 |
2012年 | 2779篇 |
2011年 | 3002篇 |
2010年 | 1578篇 |
2009年 | 1322篇 |
2008年 | 2417篇 |
2007年 | 2418篇 |
2006年 | 2224篇 |
2005年 | 2099篇 |
2004年 | 1871篇 |
2003年 | 1622篇 |
2002年 | 1630篇 |
2001年 | 237篇 |
2000年 | 205篇 |
1999年 | 229篇 |
1998年 | 316篇 |
1997年 | 246篇 |
1996年 | 178篇 |
1995年 | 186篇 |
1994年 | 138篇 |
1993年 | 129篇 |
1992年 | 81篇 |
1991年 | 66篇 |
1990年 | 66篇 |
1989年 | 61篇 |
1988年 | 54篇 |
1987年 | 57篇 |
1986年 | 43篇 |
1985年 | 24篇 |
1984年 | 37篇 |
1983年 | 43篇 |
1982年 | 34篇 |
1981年 | 22篇 |
1980年 | 18篇 |
1979年 | 19篇 |
1976年 | 13篇 |
1974年 | 14篇 |
1973年 | 12篇 |
1972年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Belinda Garner Andrew M. Chanen Lisa Phillips Dennis Velakoulis Stephen J. Wood Henry J. Jackson Christos Pantelis Patrick D. McGorry 《Psychiatry Research: Neuroimaging》2007,156(3):257-261
This study used magnetic resonance imaging to examine pituitary gland volume (PGV) in teenage patients with a first presentation of borderline personality disorder (BPD). No difference in PGV was observed between healthy controls (n = 20) and the total BPD cohort (n = 20). However, within the BPD cohort, those exposed to childhood trauma (n = 9) tended to have smaller pituitaries (− 18%) than those with no history of childhood trauma (n = 10). These preliminary findings suggest that exposure to childhood trauma, rather than BPD, per se, might be associated with reduced PGV, possibly reflecting hypothalamic–pituitary–adrenal axis dysfunction. 相似文献
82.
83.
Lisa Day RN MSN Theresa Drought RN MSN Anne J Davis RN PhD DNSc FAAN 《Journal of advanced nursing》1995,21(2):295-298
Nurses often institute artificial feeding for patients who would otherwise starve Recently, the courts in the United States have favoured withholding or withdrawing feedings from patients who currently refuse or previously gave some indication they would refuse artificial nutrition and hydration This paper investigates under what circumstances nurses feel justified in withholding artificial nutrition and hydration Structured interviews were conducted with 40 cancer care nurses from two sites, and 40 dementia care nurses from two sites The interviews were based on two vignettes, one involving an alert patient with terminal cancer, the other a patient suffering end-stage Alzheimer's dementia, and were analysed for themes coinciding with principles of deontological ethics Investigators found that autonomy, beneficence and non-maleficence most often guided nurses' decisions to withhold or implement artificial feeding 相似文献
84.
John D Morris Elizabeth T Golub Shruti H Mehta Lisa P Jacobson Stephen J Gange 《AIDS research and therapy》2007,4(1):12-8
Background
Sustained use of antiretroviral therapy has been consistently shown to be one of the primary predictors of long-term effectiveness. Switching and discontinuation reflect patient and provider decisions that may limit future treatment options. In this study, we utilize data reported at semi-annual study visits from three prospective cohort studies, the AIDS Link to IntraVenous Exposure (ALIVE), the Women's Interagency HIV Study (WIHS), and the Multicenter AIDS Cohort Study (MACS), to investigate determinants of HAART modification with a particular focus on reported injection drug use (IDU). 相似文献85.
86.
Robert C Stanton Lisa D Mayer Nancy E Oriol Katharine K Treadway Daniel C Tosteson 《Academic medicine》2007,82(5):516-520
An excellent physician must be aware of the countless issues that affect each patient's health. Many medical education programs expose students to a broad spectrum of disparate knowledge and hope they will integrate all the pieces into a coherent whole. The authors describe an explicit approach to integration used at Harvard Medical School since 2003 that aims to enhance students' learning in medical school and throughout their medical careers: the Mentored Clinical Casebook Project (MCCP). The MCCP is constructed on the premise that such integration does not occur suddenly but, rather, is an unending process. A first-year student is assigned to one clinician and follows one patient for one year. The student is expected to spend as much time with the patient as possible, in both clinical and nonclinical settings, seek help from the clinician, and consult other experts and sources to develop a complete picture of the patient's life. The student must produce a casebook that includes, but is not limited to, the patient's history; basic science, clinical, socioeconomic, and cultural issues; and self-reflection. The MCCP is intended to allow students to develop a deeper and more diverse understanding of what comprises a patient's health care life, to discern the patient as a person and the person as a patient. This educational project has been popular with students since its inception, providing them with a personal framework from which to address the needs of future patients and introducing them to how much they will continue to learn from their patients. 相似文献
87.
Keith J. Slifer Melissa Beck Adrianna Amari Tanya Diver Lisa Hilley Alana Kane Sharon McDonnell 《Children's Health Care》2003,32(2):81-101
This study investigated relationships between child/parent dissatisfaction with child facial appearance and the self-concept/social competence of 8- to 15-year-old children with (N = 34) and without (N = 34) oral clefts. Children in both groups had normative psychosocial adjustment, but also reported moderate dissatisfaction with facial appearance. Cleft group parents were more likely to agree with their child's dissatisfaction. When cleft group parents were more dissatisfied with child facial appearance, their children reported better quality of life. Results suggest that parents of children with clefts reporting greater dissatisfaction may respond in positive ways that enhance quality of life. 相似文献
88.
What Are the Etiology and Epidemiology of Out‐of‐hospital Pediatric Cardiopulmonary Arrest in Ontario,Canada? 总被引:1,自引:0,他引:1
Richard Bradley Gerein BSc MD Martin H. Osmond MDCM Ian G. Stiell MSc MD Lisa P. Nesbitt MHA Starla Burns BSc 《Academic emergency medicine》2006,13(6):653-658
Background: Pediatric cardiopulmonary arrest (CPA) outside of the hospital has a very high mortality rate. Objectives: To evaluate the etiology and initial compromise of pediatric CPA cases in hopes of developing strategies to improve out‐of‐hospital resuscitation. Methods: The Ontario Prehospital Advanced Life Support (OPALS) study was a large multicenter initiative to evaluate the impact of emergency medical services (EMS) programs on 17 communities with 40,000 critically ill and injured patients who were older than 11 years. As part of this study, the authors conducted a retrospective observational cohort study that included all children younger than 18 years of age with out‐of‐hospital CPA, during an 11‐year period from 1991–2002. CPA was defined as patient being pulseless, apneic, and requiring chest compressions. Data were collected from ambulance call reports and centralized dispatch data and were reviewed by two independent investigators. Results: There were 503 children with CPA in the sample. Mean age was 5.6 years (range, 0–17 yr); 58.4% of patients were male, and 37.8% were younger than 1 year of age. Cardiopulmonary resuscitation (CPR) first was started by a bystander in 32.4% of cases, whereas 66.0% were unwitnessed arrests. Initial rhythms were asystole 77.2% of the time, pulseless electrical activity 16.4% of the time, and ventricular fibrillation or ventricular tachycardia 4% of the time. Annual incidence was 9.1/100,000 children. CPA was witnessed in 34.0% of cases; 80.7% of these were bystander‐witnessed, and 18.1% were EMS‐witnessed. Primary pathogenic cause of arrest was medical in 61.2% of cases, trauma in 37.2% of cases, and indeterminate in 1.6% of cases. Initial underlying physiologic compromise of witnessed arrests was judged to be respiratory in 39.8% of cases, sudden collapse (presumed electrical) in 16.4% of cases, progressive shock in 1.2% of cases, and indeterminate in 42.6% of cases. Presumed etiology was trauma, 37.6%; sudden infant death syndrome (SIDS), 20.3%; and respiratory disease, 11.6%, most commonly. Survival to hospital discharge was 2.0%. Conclusions: This is one of the largest population‐based, prospective cohorts of pediatric CPA reported to date, and it reveals that most pediatric arrests are unwitnessed and receive no bystander CPR. Those that are witnessed most often are caused by respiratory arrests or trauma. Trauma, SIDS, and respiratory disease are the most common etiologies overall. These data are vital to planning large resuscitation trials looking at specific interventions (i.e., increasing bystander CPR) and highlight the need for better strategies for prevention and early recognition. 相似文献
89.
A double blind, placebo controlled trial of nicardipine in the treatment of high Doppler Flow Velocity (DFV) following severe head injury (Glasgow Coma Score (GSC) less than or equal to 8) was performed. Thirty patients with high DFV (greater than or equal to 100 cm/s for 6 h duration) on transcranial Doppler ultrasound, were treated with nicardipine or placebo for 24 h (2.5 mg/h, increasing in steps of 2.5 mg/h at 2 h intervals (maximum rate 7.5 mg/h) depending on response of DFV). DFV was measured hourly for 24 h and then every 12 h for 2 days. Nicardipine significantly reduced DFV below the threshold of 100 cm/s (16/19 cf placebo 3/11, chi-square p less than 0.001). In the nicardipine treated group maximum DFV was significantly reduced (p less than 0.001) and time with DFV below 100 was significantly longer. Rises in DFV were significantly reduced by the drug if the DFV was normal at the time of entry. High DFV returned on cessation of the infusion. No unexpected or adverse side effects were seen. No clinical benefit was demonstrable. 相似文献
90.
Resorption rate and biocompatibility characteristics of two polyester ventilation tubes in a guinea pig model 总被引:5,自引:0,他引:5
Becky L. Massey MD Xuejun Wen PHD L. Ralph Rohr MD Patrick A. Tresco PHD Lisa Dahlstrom MS Albert H. Park MD 《Otolaryngology--head and neck surgery》2004,131(6):921-925
OBJECTIVES: Determine the resorption rate and biocompatibility characteristics of 2 polyester ventilation tubes, and to determine whether soap and water exposure accelerates polyester tube degradation. STUDY DESIGN AND SETTING: 50/50 poly (D, L-lactide-co-glycolide; PLGA-50) and poly (L-lactide; PLA) polymers were placed into the tympanic membranes of Hartley pigmented guinea pigs. Integrity of the tubes was determined by weekly otoscopic examination. Biocompatibility was assessed by comparing auditory brainstem response (ABR) thresholds and by examining tympanic membrane changes following tube resorption. Shah minigrommet ventilation tubes were used as controls. In the second portion of this study, implanted PLGA-50 and PLA tubes were exposed weekly to a mixture of soap and water (1:5) until complete resorption was observed. Biocompatibility was assessed by periodic ABR testing and tympanic membrane examination. RESULTS: The PLA tubes remained in the tympanic membrane for a longer period (63.2 +/- 19.3 days) than the PLGA-50 (18.8 +/- 8.1 days). The tympanic membrane and resorbable tube interface demonstrated equivalent findings for auditory thresholds and tissue histopathology at the implant site compared to nonresorbable controls. The resorption behavior was not altered by exposure to soap and water. Tympanic membranes of all animals following tube degradation and soap water exposure were intact with minimal scarring and no signs of persistent foreign body response. The histological analysis showed that implantation of resorbable tubes was not accompanied by secondary infection with otorrhea through the tube, did not result in a permanent perforation or dislocation of the tube into the middle ear cavity, and was not followed by excess tympanosclerosis or localized or diffuse membrane atrophy. CONCLUSIONS AND SIGNIFICANCE: Resorbable polyester pressure equalization tubes demonstrate predictable resorption behavior and similar biocompatibility characteristics when compared with nonresorbable Shah minigrommet ventilation tubes. Exposure to soap water does not accelerate polyester tube degradation nor change the host tissue response during the indwelling period or after complete resorption. The data suggests that resorbable ventilation tubes are substantially equivalent to other FDA-approved tympanostomy devices with regard to safety and biocompatibility in the guinea pig model examined and may provide improved clinical performance by combining this approach with sustained release technology. EBM RATING: B-2. 相似文献