收费全文 | 2435068篇 |
免费 | 200734篇 |
国内免费 | 4377篇 |
耳鼻咽喉 | 35195篇 |
儿科学 | 74484篇 |
妇产科学 | 64597篇 |
基础医学 | 343624篇 |
口腔科学 | 69445篇 |
临床医学 | 219808篇 |
内科学 | 482634篇 |
皮肤病学 | 49852篇 |
神经病学 | 205765篇 |
特种医学 | 97157篇 |
外国民族医学 | 886篇 |
外科学 | 367505篇 |
综合类 | 56560篇 |
现状与发展 | 1篇 |
一般理论 | 999篇 |
预防医学 | 198544篇 |
眼科学 | 56878篇 |
药学 | 182472篇 |
4篇 | |
中国医学 | 4574篇 |
肿瘤学 | 129195篇 |
2018年 | 26659篇 |
2017年 | 20240篇 |
2016年 | 21985篇 |
2015年 | 24907篇 |
2014年 | 35194篇 |
2013年 | 53506篇 |
2012年 | 73496篇 |
2011年 | 77013篇 |
2010年 | 44884篇 |
2009年 | 42585篇 |
2008年 | 72543篇 |
2007年 | 77064篇 |
2006年 | 77693篇 |
2005年 | 75755篇 |
2004年 | 72742篇 |
2003年 | 70075篇 |
2002年 | 69134篇 |
2001年 | 113579篇 |
2000年 | 117710篇 |
1999年 | 99282篇 |
1998年 | 28083篇 |
1997年 | 25647篇 |
1996年 | 25587篇 |
1995年 | 24711篇 |
1994年 | 23254篇 |
1993年 | 21640篇 |
1992年 | 79865篇 |
1991年 | 76900篇 |
1990年 | 74059篇 |
1989年 | 71291篇 |
1988年 | 66239篇 |
1987年 | 65219篇 |
1986年 | 61748篇 |
1985年 | 58802篇 |
1984年 | 44524篇 |
1983年 | 37921篇 |
1982年 | 22984篇 |
1981年 | 20443篇 |
1979年 | 41649篇 |
1978年 | 29194篇 |
1977年 | 24529篇 |
1976年 | 23004篇 |
1975年 | 24161篇 |
1974年 | 29971篇 |
1973年 | 28348篇 |
1972年 | 26497篇 |
1971年 | 24390篇 |
1970年 | 23048篇 |
1969年 | 21361篇 |
1968年 | 19387篇 |
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Objectives
To determine the incidence of incisional hernia (IH) in the extraction incision (EI) in colorectal resection for cancer. To analyze whether the location of the incision has any relationship with the incidence of hernias and whether mesh could be useful for prevention in high-risk patients.Methods
Retrospective review of the colon and rectal surgery database from January 2015 to December 2016. Data were classified into 2 groups, transverse (TI) and midline incision (MI), and the latter was divided into 2 subgroups (mesh [MIM] and suture [MIS]). Patients were classified using the HERNIAscore. Hernias were diagnosed by clinical and/or CT examination.Results
A total of 182 out of 210 surgical patients were included. After a median follow-up of 13.0 months, 39 IH (21.9%) were detected, 23 of which (13.4%) were in the EI; their frequency was lower in the TI group (3.4%) and in the MIM group (5.9%) than in the MIS group (29.5%; p = 0.007). The probability of developing IH in the MIS group showed an OR = 11.7 (95%CI: 3.3-42.0) compared to the TI group and 4.3 (IC 95%: 1.1-16.3) versus the MIM group.Conclusions
The location of the incision is relevant to avoid incisional hernias. Transverse incisions should be used as the first option. When a midline incision is needed, a prophylactic mesh could be considered in high risk patients because it is safe and associated with low morbidity. 相似文献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Methods: Data from 1392 girls, aged 9 to 10 at baseline and followed for 10?years, in the National Heart, Lung, and Blood Institute’s National Growth and Health Study were used to examine the association between usual egg intake alone and in combination with other healthy lifestyle factors and late adolescent lipid levels, fasting glucose, and insulin resistance, measured as homeostasis model assessment of insulin resistance (HOMA-IR). Diet was assessed using 3-day food records during eight examination cycles. Girls were classified according to usual weekly egg intake, ages 9–17?years:?<1 egg/wk (n?=?361), 1 to <3 eggs/wk (n?=?703), and ≥3 eggs/wk (n?=?328). Analysis of covariance modeling was used to control for confounding by other behavioral and biological risk factors.
Results: Girls with low, moderate, and high egg intakes had adjusted low-density lipoprotein cholesterol levels of 99.7, 98.8, and 95.5 mg/dL, respectively (p?=?0.0778). In combination with higher intakes of fiber, dairy, or fruits and vegetables, these beneficial effects were stronger and statistically significant. There was no evidence that ≥3 eggs/wk had an adverse effect on lipids, glucose, or HOMA-IR. More active girls who consumed ≥3 eggs/wk had the lowest levels of insulin resistance.
Conclusion: These results suggest that eggs may be included as part of a healthy adolescent diet without adverse effects on glucose, lipid levels, or insulin resistance. 相似文献