全文获取类型
收费全文 | 9558篇 |
免费 | 885篇 |
国内免费 | 351篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 221篇 |
妇产科学 | 136篇 |
基础医学 | 1168篇 |
口腔科学 | 237篇 |
临床医学 | 888篇 |
内科学 | 1272篇 |
皮肤病学 | 329篇 |
神经病学 | 810篇 |
特种医学 | 301篇 |
外科学 | 1011篇 |
综合类 | 851篇 |
预防医学 | 1296篇 |
眼科学 | 98篇 |
药学 | 792篇 |
中国医学 | 1069篇 |
肿瘤学 | 226篇 |
出版年
2024年 | 26篇 |
2023年 | 339篇 |
2022年 | 448篇 |
2021年 | 659篇 |
2020年 | 565篇 |
2019年 | 611篇 |
2018年 | 581篇 |
2017年 | 450篇 |
2016年 | 360篇 |
2015年 | 340篇 |
2014年 | 699篇 |
2013年 | 673篇 |
2012年 | 537篇 |
2011年 | 622篇 |
2010年 | 411篇 |
2009年 | 427篇 |
2008年 | 424篇 |
2007年 | 388篇 |
2006年 | 301篇 |
2005年 | 282篇 |
2004年 | 222篇 |
2003年 | 223篇 |
2002年 | 147篇 |
2001年 | 116篇 |
2000年 | 107篇 |
1999年 | 116篇 |
1998年 | 83篇 |
1997年 | 67篇 |
1996年 | 59篇 |
1995年 | 68篇 |
1994年 | 43篇 |
1993年 | 43篇 |
1992年 | 37篇 |
1991年 | 31篇 |
1990年 | 37篇 |
1989年 | 32篇 |
1988年 | 24篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 37篇 |
1984年 | 27篇 |
1983年 | 22篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Raymond E. Chen Emma Knapp Bowen Qiu Anthony Miniaci Hani A. Awad Ilya Voloshin 《Seminars in Arthroplasty》2022,32(1):145-153
BackgroundThe purpose of this study was to compare initial fixation strength between various stemless and stemmed humeral components and to correlate implant fixation strength with bone mineral density (BMD).MethodsFive humeral stem designs were investigated: Stemless-A (four hollow fins), Stemless-B (central body, three solid fins), Stemless-C (central screw, peripheral rim-fit), Short stem (50 mm), and Standard stem (130 mm). Fifty cadaveric human humerii were obtained and divided into five groups. BMD within the humeral head was determined for all samples. The mean BMD was similar between groups. The 25 samples with the lowest and highest BMDs were categorized as “Low” and “High,” respectively, with a BMD threshold of 0.35 g/cm2, creating BMD subgroups. After implantation, each sample underwent a standardized biomechanical testing protocol, with axial loading followed by torsional loading. Sensors attached to the specimen recorded micromotion throughout testing. Axial loading consisted of cyclic loading for 100 cycles at 3 peak forces (220, 520, and 820 N). Torsional loading consisted of 100 cycles of internal/external rotation at 0.1 Hz at 6 peak torques, or until failure (±2.5, 5, 7.5, 10, 12.5, and 15 Nm). Failure was defined as the torque at which any bone fracture, implant detachment from anchor/stem, or an excess of 50° internal/external rotation occurred. Groups and BMD subgroups were compared.ResultsAt maximal axial loading, Stemless-B demonstrated greater micromotion (540 μm) than Stemless-C (192 μm) (P = .003). Stemless-B and Stemless-A (387 μm) also had greater micromotion than Short stem (118 μm, P < .001, P = .03) and Standard stem (85 μm, P < .001, P = .01). When comparing low-BMD samples at maximal axial loading, these differences were accentuated, but comparison of high-BMD samples showed no significant differences between groups. Torsional testing demonstrated that Standard stem failed at greater torque (7.2 Nm) than Stemless-B (2.3 Nm, P < .001), Stemless-A (1.9 Nm, P < .001), and Stemless-C (3.9 Nm, P = .01). When comparing torsional testing results of low-BMD samples, both Standard stem and Short stem failed at greater torque than Stemless-B (P = .02, P = .003) and Stemless-A (P = .03, P = .004) but failed at a similar torque to Stemless-C. Torsional testing of high-BMD samples showed that Standard stem failed at a greater torque than all stemless designs.ConclusionStemless humeral implants should be used with caution in low-BMD settings (<0.35 g/cm2). A central screw and peripheral rim-fit stemless anchor design demonstrated greater fixation strength at low BMD when compared with other designs, while all stemless designs performed similarly at high BMD.Level of evidenceBasic Science Study; Cadaveric Study 相似文献
3.
《Journal of the Academy of Nutrition and Dietetics》2022,122(11):2060-2071
BackgroundVoices for Food was a longitudinal community, food pantry–based intervention informed by the social ecological model, and designed to improve food security, dietary intake, and quality among clients, which was carried out in 24 rural food pantries across 6 Midwestern states.ObjectiveOur objective was to evaluate changes in adult food security, dietary intake, and quality from baseline (2014) to follow-up (2016), and to assess the role of adult food security on dietary outcomes.DesignA multistate, longitudinal, quasi-experimental intervention with matched treatment and comparison design was used to evaluate treatment vs comparison group changes over time and changes in both groups over time.Participants/settingAdult food pantry clients (n = 617) completed a demographic food security survey, and up to three 24-hour dietary recalls at baseline (n = 590) and follow-up (n = 160).InterventionCommunity coaching served as the experimental component, which only “treatment” communities received, and a food council guide and food pantry toolkit were provided to both “treatment” and matched “comparison” communities.Main outcome measuresChange in adult food security status, mean usual intakes of nutrients and food groups, and Healthy Eating Index-2010 scores were the main outcome measures.Statistical analyses performedLinear mixed models estimated changes in outcomes by intervention group and by adult food security status over time.ResultsImprovements in adult food security score (–0.7 ± 0.3; P = .01), Healthy Eating Index-2010 total score (4.2 ± 1.1; P < .0001), and empty calories component score (3.4 ± 0.5; P <.0001) from baseline to follow-up were observed in treatment and comparison groups, but no statistically significant changes were found for adult food security status, dietary quality, and usual intakes of nutrients and food groups between the 2 groups over time. The intervention effect on dietary quality and usual intake changes over time by adult food security status were also not observed.ConclusionsFood pantry clients in treatment and comparison groups had higher food security and dietary quality at the follow-up evaluation of the Voices for Food intervention trial compared with baseline, despite the lack of difference among the groups as a result of the experimental coaching component. 相似文献
4.
5.
《Journal of Clinical Orthopaedics and Trauma》2021,12(6):976-982
ObjectiveMultiple treatment options for acetabular fractures in geriatric patients exist. However, no large-scale studies have reported the outcomes of acute total hip arthroplasty (THA) in this patient population. We systematically evaluated all available evidence to characterize clinical outcomes, complications, and revisions of acute THA for acetabular fractures in geriatric patients.MethodsMeta-analysis of 21 studies of 430 acetabular fractures with mean follow-up of 44 months (range, 17−97 months). Two independent researchers searched and evaluated the databases of Ovid, Embase, and United States National Library of Medicine using a Boolean search string up to December 2019. Population demographics and complications, including presence of heterotopic ossification (HO), dislocation, infection, revision rate, neurological deficits, and venous thromboembolic event (VTE), were recorded and analyzed.ResultsWeighted mean Harris Hip Score was 83.3 points, and 20% of the patients had reported complications. The most common complication was HO, with a rate of 19.5%. Brooker grade III and IV HO rates were lower at 6.8%. Hip dislocation occurred at a rate of 6.1%, 4.1% of patients developed VTE, deep infection occurred in 3.8%, and neurological complications occurred in 1.9%. Although the revision rate was described in most studies, we were unable to perform a survival analysis because the time to each revision was described in only a few studies. The revision rate was 4.3%.ConclusionsAcute THA is a viable option for treatment of acetabular fracture and can result in acceptable clinical outcomes and survivorship rates in older patients but with an associated complication rate of approximately 20%. Considering the limited treatment options, THA might be a viable alternative for appropriately selected patients. 相似文献
6.
《European journal of surgical oncology》2022,48(4):707-717
BackgroundChyle leak (CL) is a clinically relevant complication after pancreatectomy. Its incidence and the associated risk factors are ill defined, and various treatments options have been described. There is no consensus, however, regarding optimal management. The present study aims to systematically review the literature on CL after pancreatectomy.MethodsA systematic review from PubMed, Scopus and Embase database was performed. Studies using a clear definition for CL and published from January 2000 to January 2021 were included. The PRISMA guidelines were followed during all stages of this systematic review. The MINORS score was used to assess methodological quality.ResultsLiterature search found 361 reports, 99 of which were duplicates. The titles and abstracts of 262 articles were finally screened. The references from the remaining 181 articles were manually assessed. After the exclusions, 43 articles were thoroughly assessed. A total of 23 articles were ultimately included for this review. The number of patients varied from 54 to 3532. Incidence of post pancreatectomy CL varied from 1.3% to 22.1%. Main risk factors were the extent of the surgery and early oral or enteral feeding. CL dried up spontaneously or after conservative management within 14 days in 53% to 100% of the cases.ConclusionsThe extent of surgery is the most common predictor of risk of CL. Conservative treatment has been shown to be effective in most cases and can be considered the treatment of choice. We propose a management algorithm based on the current available evidence. 相似文献
7.
《Nutrition, metabolism, and cardiovascular diseases : NMCD》2022,32(5):1165-1174
Background and aimsThe extent to which dietary patterns influence the risk of abnormal blood lipids throughout young adulthood remains unclear. The aim was to investigate whether early young adulthood dietary patterns predict the risk of abnormal blood lipids during later young adulthood.Methods and resultsWe used data from a long running birth cohort study in Australia. Western dietary pattern rich in meats, processed foods and high-fat dairy products and prudent pattern rich in fruit, vegetables, fish, nuts, whole grains and low-fat dairy products were derived using principal component analysis at the 21-year follow-up from dietary data obtained using a food frequency questionnaire. After 9-years, fasting blood samples of all participants were collected and their total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterols and triglyceride (TG) levels were measured. Abnormal blood lipids were based on clinical cut-offs for total, LDL and HDL cholesterols, and TG and relative distributions for total:HDL and TG:HDL cholesterols ratios. Log-binomial models were used to estimate risk of each outcome in relation to dietary patterns. Greater adherence to the Western pattern predicted increased risks of high LDL (RR: 1.47; 95%CI: 1.06, 2.03) and TG (1.90; 1.25, 2.86), and high ratios of total:HDL (1.48; 1.00, 2.19) and TG:HDL (1.78; 1.18, 2.70) cholesterols in fully adjusted models. Conversely, a prudent pattern predicted reduced risks of low HDL (0.58; 0.42, 0.78) and high TG (0.66; 0.47, 0.92) and high total:HDL (0.71; 0.51, 0.98) and TG:HDL (0.61; 0.45, 0.84) cholesterols ratios.ConclusionThis is the first prospective study to show greater adherence to unhealthy Western diet predicted increased risks of abnormal blood lipids, whereas healthy prudent diet predicted lower such risks in young adults. Addressing diets in early course may improve cardiovascular health of young adults. 相似文献
8.
《Biomedical and environmental sciences : BES》2022,35(9):773-781
ObjectiveImprovement in the quality of life is reflected in the narrowing of the gap between health-adjusted life expectancy (HALE) and life expectancy (LE). The effect of megacity expansion on narrowing the gap is rarely reported. This study aimed to disclose this potential relationship.MethodsAnnual life tables were constructed from identified death records and population counts from multiple administrative sources in Guangzhou, China, from 2010 to 2020. Joinpoint regression was used to evaluate the temporal trend. Generalized principal component analysis and multilevel models were applied to examine the county-level association between the gap and social determinants.ResultsAlthough LE and HALE in megacities are increasing steadily, their gap is widening. Socio-economic and health services are guaranteed to narrow this gap. Increasing personal wealth, a growing number of newborns and healthy immigrants, high urbanization, and healthy aging have helped in narrowing this gap.ConclusionIn megacities, parallel LE and HALE growth should be highly considered to narrow their gap. Multiple social determinants need to be integrated as a whole to formulate public health plans. 相似文献
9.
《Journal of the Academy of Nutrition and Dietetics》2022,122(6):1099-1113.e3
BackgroundLittle is known about breakfast habits of the Latin American (LA) population to support nutritional recommendations for a balanced breakfast in this region.ObjectiveTo evaluate the nutritional composition of breakfast in the LA population and to propose recommendations for a balanced breakfast.DesignThis multicenter cross-sectional study evaluated food and nutrient intake of nationally representative samples of urban populations of 8 LA countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru, and Venezuela) in 2014-2015.Participants/settingThe sample comprised 8714 participants from the Latin American Study of Nutrition and Health, aged 15 to 65 years, randomly recruited according to geographical location, sex, age, and socioeconomic level.Main outcome measuresTwo 24-hour recalls were used to examine dietary intake. Breakfast consumers were stratified by tertiles of Nutrient-Rich Foods Index 9.3 (NRF9.3) to assess the overall diet quality of individuals. Nutrient intake at breakfast of those in the upper tertile of NRF9.3 pooled for the 8 countries was used as a reference for the development of recommendations for LA adolescents and adults.Statistical analysesComparison of food and nutrient intake of breakfast across NRF9.3 tertiles were analyzed using the Kruskal-Wallis rank sum test.ResultsOverall breakfast was an important contributor to protein, carbohydrate, and B vitamin intakes but also to added sugar and total and saturated fat intakes relative to daily intakes. Individuals in the upper NRF9.3 tertile had higher intake of key micronutrients such as calcium and potassium at breakfast compared with other tertiles. White breads/rolls/tortillas were the most consumed food group (60%), followed by butter/margarine (40%) and coffee/tea without milk (34%-50%).ConclusionsBreakfast contributed to the daily intake of B vitamins, protein, and carbohydrates but also added sugar and total and saturated fat intakes for all countries. The proposed recommendations support the nutrient density of existing highest-quality breakfast in the LA population while addressing concerns about nutrients to be encouraged or reduced. 相似文献
10.