全文获取类型
| 收费全文 | 3364058篇 |
| 免费 | 255735篇 |
| 国内免费 | 6643篇 |
专业分类
| 耳鼻咽喉 | 49829篇 |
| 儿科学 | 104745篇 |
| 妇产科学 | 92811篇 |
| 基础医学 | 469936篇 |
| 口腔科学 | 100048篇 |
| 临床医学 | 300607篇 |
| 内科学 | 650697篇 |
| 皮肤病学 | 71697篇 |
| 神经病学 | 275492篇 |
| 特种医学 | 136187篇 |
| 外国民族医学 | 1316篇 |
| 外科学 | 513068篇 |
| 综合类 | 78974篇 |
| 现状与发展 | 7篇 |
| 一般理论 | 1308篇 |
| 预防医学 | 263948篇 |
| 眼科学 | 80867篇 |
| 药学 | 251873篇 |
| 9篇 | |
| 中国医学 | 6462篇 |
| 肿瘤学 | 176555篇 |
出版年
| 2018年 | 34440篇 |
| 2017年 | 27745篇 |
| 2016年 | 29722篇 |
| 2015年 | 34403篇 |
| 2014年 | 47291篇 |
| 2013年 | 69823篇 |
| 2012年 | 97074篇 |
| 2011年 | 98356篇 |
| 2010年 | 57631篇 |
| 2009年 | 56821篇 |
| 2008年 | 92055篇 |
| 2007年 | 99071篇 |
| 2006年 | 100220篇 |
| 2005年 | 104220篇 |
| 2004年 | 102210篇 |
| 2003年 | 95696篇 |
| 2002年 | 90632篇 |
| 2001年 | 151165篇 |
| 2000年 | 155274篇 |
| 1999年 | 133352篇 |
| 1998年 | 37565篇 |
| 1997年 | 34128篇 |
| 1996年 | 33297篇 |
| 1995年 | 32187篇 |
| 1994年 | 30153篇 |
| 1993年 | 28056篇 |
| 1992年 | 107956篇 |
| 1991年 | 104755篇 |
| 1990年 | 101996篇 |
| 1989年 | 98704篇 |
| 1988年 | 91671篇 |
| 1987年 | 90369篇 |
| 1986年 | 86126篇 |
| 1985年 | 82075篇 |
| 1984年 | 61879篇 |
| 1983年 | 52622篇 |
| 1982年 | 31549篇 |
| 1981年 | 28208篇 |
| 1979年 | 58961篇 |
| 1978年 | 41531篇 |
| 1977年 | 35391篇 |
| 1976年 | 32750篇 |
| 1975年 | 36017篇 |
| 1974年 | 43893篇 |
| 1973年 | 41917篇 |
| 1972年 | 39759篇 |
| 1971年 | 37248篇 |
| 1970年 | 35186篇 |
| 1969年 | 33042篇 |
| 1968年 | 30409篇 |
排序方式： 共有10000条查询结果，搜索用时 31 毫秒
221.
222.
223.
224.
225.
Background
Many patients undergoing below knee amputations (BKA) return for subsequent unplanned operations, hospital readmission, or postoperative complications. This unplanned medical management negatively impacts both patient outcomes and our healthcare system. This study primarily investigates the risk factors for unplanned reoperation following BKA.Methods
Below knee amputations from the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database from the years 2012–2014 were identified by CPT code 27880 for amputation through the tibia and fibula. Our query identified 4631 BKA cases, including 30 day complications. Multivariate logistic regression modeling was performed on several patient demographic and disease factors to assess for independent predictors of unplanned reoperation. Secondary outcomes of unplanned and related readmissions (related to the procedure), major complications, minor complications, and mortality were also included in the analysis.Results
Of 4631 BKAs identified, 9.63% (446/4631) underwent unplanned reoperations and 8.75% (405/4631) had unplanned and related readmissions. Major complications were experienced by 12.8% (593/4631) and minor complications by 8.7% (401/4631). Thirty day mortality rate was 5.14% (238/4631). The most common procedures for unplanned operations were thigh amputations (128/446, 28.7%), debridement/secondary closure (114/446, 25.6%), and revision leg amputations (46/446, 10.32%). Factors associated with an increased risk of unplanned reoperation included patients transferred from another facility (Adjusted Odds Ratio [AOR]?=?1.28; p?=?.04), recent smokers (AOR?=?1.34; p?=?.02), bleeding disorder (AOR?=?1.30; p?=?.02), and preoperative ventilator use (AOR?=?2.38; p?=?.01).Conclusion
Patients that were ongoing/recent smokers, had diagnosed bleeding disorders, required preoperative ventilator use, or were transferred in from another facility were associated with the highest risks of reoperation following BKA. This patient population experiences high rates of reoperation, readmission, complication, and mortality. 相似文献226.
Objectives: The steeling effect suggests that early-life adversity can have a beneficial impact later in life. However, little is known about its underlying mechanisms and long-term outcomes . The study aimed to examine the role of early-life adversity (ELA) on successful aging, and whether this relationship can be explained by mental and physical health.
Method: Socio-demographics, early-life adversity (ELA), individual quality of life (iQoL), and mental and physical health of 270 individuals (Mage = 66.82 years, 71.5% female) were assessed. Polynomial regressions and mediation analyses were conducted.
Results: Significant inverse U-shaped associations were found between ELA and iQoL (β = ?.59, p = .005) and between ELA and mental health (β = ?.64, p = .002), but not between ELA and physical health. Furthermore, mental health significantly mediated the relationship between ELA and iQoL (b = ?.84, BCa CI [?1.66, ?.27]).
Conclusion: Highest level of individual quality of life (i.e. successful aging) was related to a moderate amount of ELA. Additionally, mental health significantly mediated this relationship. These findings suggest that some amount of ELA could be beneficial for successful aging. Resource-focused interventions are needed to improve health and promote successful aging for an underdetected, at-risk subgroup with low early-life adversity. 相似文献
227.
Accuracy and Precision of Acetabular Component Placement With Imageless Navigation in Obese Patients
Leonard T. Buller Alexander S. McLawhorn Jose A. Romero Peter K. Sculco David J. Mayman 《The Journal of arthroplasty》2019,34(4):693-699
Background
Obesity is a risk factor for acetabular component malposition when total hip arthroplasty is performed with manual techniques. The utility of imageless navigation in obese patients remains unknown. This study compared the accuracy and precision of imageless navigation for component orientation between obese and nonobese patients.Methods
A total of 459 total hip arthroplasties performed for osteoarthritis using imageless navigation were reviewed from a single surgeon’s institutional review board–approved database. Einzel-Bild-Roentgen Analyse determined component orientation on 6-week postoperative anteroposterior radiographs. Mean orientation error (accuracy) and precision were compared between obese (body mass index ≥ 30 kg/m2) and nonobese patients. Regression analysis evaluated the influence of obesity on component position.Results
The difference in mean inclination and anteversion between obese and nonobese groups was 1.1° (43.0° ± 3.5°; range, 35.8°-57.8° vs 41.9° ± 4.4°; range, 33.0°-57.1° and 24.9° ± 6.3°; range, 14.2°-44.3° vs 23.8° ± 6.6°; range, 7.0°-38.6°, respectively). Inclination precision was better for nonobese patients. No difference in inclination accuracy or anteversion accuracy or precision was detected between groups. And 83% of components were placed within the target range. There was no relationship between obesity (dichotomized) and component placement outside the target ranges for inclination, anteversion, or both. As a continuous variable, increased body mass index correlated with higher odds of inclination outside the target zone (odds ratio, 1.06; P = .001).Conclusion
Using imageless navigation, inclination orientation was less precise for obese patients, but the observed difference is likely not clinically relevant. Accurate superficial registration of landmarks in obese patients is achievable, and the use of imageless navigation similarly improves acetabular component positioning in obese and nonobese patients.Level of Evidence
Therapeutic Level IV. 相似文献228.
Margaret H. Lauerman Karen Irizarry Clint Sliker Brandon R. Bruns Ronald Tesoriero Thomas M. Scalea Deborah M. Stein 《Injury》2019,50(1):131-136
Background
Current blunt cerebrovascular injury (BCVI) grading grossly differentiates injury characteristics such as luminal stenosis (LS) and aneurysmal disease. The effect of increasing degree of LS beyond the current BCVI grading scale on stroke formation is unknown.Study Design
BCVI over a 3-year period were retrospectively reviewed. To investigate influence of LS beyond the BCVI grading scale within aneurysmal and non-aneurysmal BCVI, grade 2 BCVI were subdivided into BCVI with ≥ 25% and ≤ 50% LS and BCVI with > 50% and ≤ 99% LS. Grade 3 BCVI were subdivided into BCVI with pseudoaneurysm (PSA) without LS and BCVI with PSA and LS. We hypothesized increased LS beyond the current BCVI grade distinctions would be associated with higher rates of stroke formation.Results
312 BCVI were included, of which 140 were carotid BCVI and 172 vertebral BCVI. Sixteen carotid BCVI underwent endovascular intervention (EI) and 19 suffered a stroke. In carotid BCVI stroke rates increased sequentially with BCVI grade except in grade 3. There was a stroke rate of 12% in grade 1 carotid BCVI, 18% in grade 2, 6% in grade 3, and 31% in grade 4. In subgroup analysis for grade 2 carotid BCVI, BCVI with > 50% and ≤ 99% LS had higher rates of stroke (22% vs. 15%, p?=?0.44) than BCVI with ≥ 25% and ≤ 50% LS. In subgroup analysis of grade 3 carotid BCVI, BCVI with PSA and LS had higher rates of stroke (9% vs. 4%, p?=?0.48) than BCVI with PSA without LS. Higher rates of EI in grade 2 carotid BCVI with > 50% and ≤ 99% LS (22% vs. 5%, p?=?0.14) and grade 3 carotid BCVI with PSA and LS (35% vs. 4%, p?=?0.01) were noted in subgroup analysis.Conclusion
Higher percentage LS beyond the currently used BCVI grading scale has a non-significantly increased rate of stroke in both aneurysmal and non-aneurysmal BCVI. Grade 3 BCVI with PSA and LS seems to be a high-risk subgroup. Use of EI confounds modern measurement of stroke risk in higher LS BCVI. 相似文献229.
230.