全文获取类型
收费全文 | 6052篇 |
免费 | 481篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 51篇 |
儿科学 | 164篇 |
妇产科学 | 173篇 |
基础医学 | 785篇 |
口腔科学 | 50篇 |
临床医学 | 827篇 |
内科学 | 1212篇 |
皮肤病学 | 134篇 |
神经病学 | 568篇 |
特种医学 | 130篇 |
外科学 | 541篇 |
综合类 | 104篇 |
一般理论 | 5篇 |
预防医学 | 851篇 |
眼科学 | 178篇 |
药学 | 368篇 |
中国医学 | 3篇 |
肿瘤学 | 396篇 |
出版年
2023年 | 55篇 |
2022年 | 86篇 |
2021年 | 176篇 |
2020年 | 144篇 |
2019年 | 217篇 |
2018年 | 186篇 |
2017年 | 155篇 |
2016年 | 176篇 |
2015年 | 163篇 |
2014年 | 246篇 |
2013年 | 304篇 |
2012年 | 479篇 |
2011年 | 476篇 |
2010年 | 214篇 |
2009年 | 198篇 |
2008年 | 395篇 |
2007年 | 359篇 |
2006年 | 349篇 |
2005年 | 329篇 |
2004年 | 341篇 |
2003年 | 290篇 |
2002年 | 241篇 |
2001年 | 64篇 |
2000年 | 60篇 |
1999年 | 54篇 |
1998年 | 54篇 |
1997年 | 45篇 |
1996年 | 34篇 |
1995年 | 23篇 |
1994年 | 35篇 |
1993年 | 25篇 |
1992年 | 38篇 |
1991年 | 45篇 |
1990年 | 35篇 |
1989年 | 31篇 |
1988年 | 28篇 |
1987年 | 33篇 |
1986年 | 26篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 17篇 |
1982年 | 14篇 |
1980年 | 18篇 |
1979年 | 22篇 |
1978年 | 17篇 |
1977年 | 18篇 |
1975年 | 16篇 |
1974年 | 17篇 |
1973年 | 14篇 |
1966年 | 14篇 |
排序方式: 共有6540条查询结果,搜索用时 15 毫秒
61.
Economic Stressors and Psychological Distress: Exploring Age Cohort Variation in the Wake of the Great Recession 下载免费PDF全文
This study examined processes linking age cohort, economic stressors, coping strategies and two indicators of psychological distress (i.e. depressive symptoms and anxiety symptoms). Structural equation models were conducted utilizing data from a national survey that was undertaken in order to understand life change consequences of the period of economic downturn from 2007 to 2009 known as the Great Recession. Findings revealed that the associations between economic stressors and symptoms of both depression and anxiety were significantly greater for members of the millennial cohort compared with baby boomers. These effects are partly explained by the greater tendency of members of the baby boomer cohort to use active coping strategies. These findings clarify the circumstances in which age matters most for the associations among economy‐related stressors, coping strategies and psychological well‐being. They highlight how difficult economic circumstances influence the availability of coping strategies and, in turn, psychological well‐being—and differently for younger and older age cohorts. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
62.
Background
Peritoneal dialysis (PD) is preferred over hemodialysis. The aim of this study was to evaluate our experience with laparoscopic PD catheter placement and omentectomy in children.Methods
We reviewed all children (N = 21) who underwent laparoscopic placement of PD catheters and omentectomy. Ages ranged from 3 months to 16 years. Five children had previous major abdominal surgery and required extensive lysis of adhesions. During the same intervention, other surgical procedures were performed using laparoscopy or open technique, including umbilical hernia repair in 3, bilateral inguinal hernia repair in 3, ventral hernia repair in 2, gastrostomy in 4, kidney biopsy in 2, and cholecystectomy in 1.Results
Thirteen children received successful kidney transplantation and no longer needed dialysis. Two children still have functioning PD catheters. One patient developed membrane failure and was converted to hemodialysis. Four patients recovered enough renal function and no longer need dialysis. There were no complications related to the laparoscopic procedure.Conclusion
Laparoscopy is ideal for PD catheter placement. It facilitates omentectomy, and it allows for the catheter to be placed in the proper position under direct vision and for lysis of adhesions to increase peritoneal surface. Other abdominal procedures can be performed laparoscopically at the same time. 相似文献63.
Extracorporeal Life Support Bridge to Ventricular Assist Device: The Double Bridge Strategy 下载免费PDF全文
Silvana F. Marasco Casey Lo Deirdre Murphy Robyn Summerhayes Margaret Quayle Adam Zimmet Michael Bailey 《Artificial organs》2016,40(1):100-106
In patients requiring left ventricular assist device (LVAD) support, it can be difficult to ascertain suitability for long‐term mechanical support with LVAD and eventual transplantation. LVAD implantation in a shocked patient is associated with increased morbidity and mortality. Interest is growing in the utilization of extracorporeal life support (ECLS) as a bridge‐to‐bridge support for these critically unwell patients. Here, we reviewed our experience with ECLS double bridging. We hypothesized that ECLS double bridging would stabilize end‐organ dysfunction and reduce ventricular assist device (VAD) implant perioperative mortality. We conducted a retrospective review of prospectively collected data for 58 consecutive patients implanted with a continuous‐flow LVAD between January 2010 and December 2013 at The Alfred Hospital, Melbourne, Victoria, Australia. Twenty‐three patients required ECLS support pre‐LVAD while 35 patients underwent LVAD implantation without an ECLS bridge. Preoperative morbidity in the ECLS bridge group was reflected by increased postoperative intensive care duration, blood loss, blood product use, and postoperative renal failure, but without negative impact upon survival when compared with the no ECLS group. ECLS stabilization improved end‐organ function pre‐VAD implant with significant improvements in hepatic and renal dysfunction. This series demonstrates that the use of ECLS bridge to VAD stabilizes end‐organ dysfunction and reduces VAD implant perioperative mortality from that traditionally reported in these “crash and burn” patients. 相似文献
64.
Analyzing treatment aggressiveness and identifying high‐risk patients in diabetic foot ulcer return to care 下载免费PDF全文
Austin C. Remington BA Tina Hernandez‐Boussard PhD Nicholus M. Warstadt BS Micaela A. Finnegan BA Robyn Shaffer BA Jereen Z. Kwong BA Catherine Curtin MD 《Wound repair and regeneration》2016,24(4):731-736
Rates of diabetes and its associated comorbidities have been increasing in the United States, with diabetic foot ulcer treatment representing a large cost to the patient and healthcare system. These ulcers often result in multiple hospital admissions. This study examined readmissions following inpatient care for a diabetic foot ulcer and identified modifiable factors associated with all‐cause 30‐day readmissions to the inpatient or emergency department (ED) setting. We hypothesized that patients undergoing aggressive treatment would have lower 30‐day readmission rates. We identified patient discharge records containing International Classification of Disease ninth revision codes for both diabetes mellitus and distal foot ulcer in the State Inpatient and Emergency Department databases from the Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project in Florida and New York, 2011–2012. All‐cause 30‐day return to care visits (ED or inpatient) were analyzed. Patient demographics and treatment characteristics were evaluated using univariate and multivariable regression models. The cohort included 25,911 discharges, having a mean age of 63 and an average of 3.8 comorbidities. The overall rate of return to care was 30%, and 21% of subjects underwent a toe or midfoot amputation during their index stay. The most common diagnosis codes upon readmission were diabetes mellitus (19%) and infection (13%). Patients with a toe or midfoot amputation procedure were less likely to be readmitted within 30 days (odds ratio: 0.78; 95% confidence interval: 0.73, 0.84). Presence of comorbidities, black and Hispanic ethnicities, and Medicare and Medicaid payer status were also associated with higher odds of readmission following initial hospitalization (p < 0.05). The study suggests that there are many factors that affect readmission rates for diabetic foot ulcer patients. Understanding patients at high‐risk for readmission can improve counseling and treatment strategies for this fragile patient population. 相似文献
65.
66.
67.
68.
Dietary lutein, zeaxanthin, and fats and the progression of age-related macular degeneration 总被引:1,自引:0,他引:1
Robman L Vu H Hodge A Tikellis G Dimitrov P McCarty C Guymer R 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》2007,42(5):720-726
BACKGROUND: To estimate the effect of dietary intake of lutein and zeaxanthin (L/Z) and fats on the progression of age-related macular degeneration (AMD). METHODS: Two hundred and fifty-four subjects identified with early age-related macular degeneration (AMD) were re-examined to determine 7-year AMD progression. Intakes of L/Z and fatty acids were estimated from food frequency questionnaires. Progression was defined by 3 different definitions, 2 quantitative and 1 qualitative, which varied in the stringency of the change required for the AMD to be deemed to have progressed. Covariates included age, smoking, AMD family history, source study, and follow-up duration. RESULTS: Energy-adjusted L/Z intake as a continuous variable was associated with AMD progression in the worse affected eye when defined by the most stringent criterion (odds ratio [OR] = 2.65, 95% confidence interval [CI] 1.13-6.22, p = 0.02). Similar associations were observed for the 2 other progression definitions (p = 0.18 and p = 0.13). Energy-adjusted omega-3 fatty acid intake modelled as a quintile median was associated with AMD progression only in the side-by-side assessment (OR = 2.56, 95% CI 1.11-5.91, p = 0.03), with borderline significance in the other 2 definitions (p = 0.05 and p = 0.08). No association of AMD progression was observed with the intake of either total fat or other subgroups: saturated, polyunsaturated, or monounsaturated fats; trans fatty acids; or omega-6 fatty acids. INTERPRETATION: The findings of the study are counterintuitive, suggesting that increased intakes of dietary L/Z and omega-3 fatty acids are associated with progression of AMD. These results may indicate that too much of a good thing might be harmful. It is possible that in this study participants adopted a more healthy diet, having been aware of their AMD status at the beginning of the study. This healthy diet was then reflected in the dietary questionnaire completed at the end of study. However, this explanation may not adequately explain why those whose AMD had progressed, on the basis of fundus signs and not symptoms such as visual acuity decline, adopted a healthier lifestyle more aggressively than those without progression. 相似文献
69.
Although second-order motion may be detected by early and automatic mechanisms, some models suggest that perceiving second-order motion requires higher-order processes, such as feature or attentive tracking. These types of attentionally mediated mechanisms could explain the motion aftereffect (MAE) perceived in dynamic displays after adapting to second-order motion. Here we tested whether there is a second-order MAE in the absence of attention or awareness. If awareness of motion, mediated by high-level or top-down mechanisms, is necessary for the second-order MAE, then there should be no measurable MAE if the ability to detect directionality is impaired during adaptation. To eliminate the subject's ability to detect directionality of the adapting stimulus, a second-order drifting Gabor was embedded in a dense array of additional crowding Gabors. We found that a significant MAE was perceived even after adaptation to second-order motion in crowded displays that prevented awareness. The results demonstrate that second-order motion can be passively coded in the absence of awareness and without top-down attentional control. 相似文献
70.
Ward KM Celebi JT Gmyrek R Grossman ME 《Journal of the American Academy of Dermatology》2002,47(4):493-496
Acute infectious purpura fulminans is a rapidly progressive syndrome of hemorrhagic skin necrosis associated with acute infection and disseminated intravascular coagulation. We report 5 cases of purpura fulminans and briefly review the literature. All cases were associated with encapsulated organisms (Streptococcus pneumoniae or Group A streptococcus), and 4 of the 5 patients had asplenism or functional hyposplenism. 相似文献