全文获取类型
收费全文 | 2069篇 |
免费 | 62篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 28篇 |
妇产科学 | 30篇 |
基础医学 | 174篇 |
口腔科学 | 33篇 |
临床医学 | 231篇 |
内科学 | 365篇 |
皮肤病学 | 8篇 |
神经病学 | 271篇 |
特种医学 | 98篇 |
外科学 | 167篇 |
综合类 | 39篇 |
一般理论 | 1篇 |
预防医学 | 364篇 |
眼科学 | 20篇 |
药学 | 195篇 |
中国医学 | 32篇 |
肿瘤学 | 80篇 |
出版年
2023年 | 127篇 |
2022年 | 213篇 |
2021年 | 121篇 |
2020年 | 169篇 |
2019年 | 103篇 |
2018年 | 69篇 |
2017年 | 75篇 |
2016年 | 103篇 |
2015年 | 71篇 |
2014年 | 247篇 |
2013年 | 108篇 |
2012年 | 71篇 |
2011年 | 42篇 |
2010年 | 74篇 |
2009年 | 79篇 |
2008年 | 27篇 |
2007年 | 34篇 |
2006年 | 29篇 |
2005年 | 12篇 |
2004年 | 11篇 |
2003年 | 18篇 |
2002年 | 12篇 |
2001年 | 17篇 |
2000年 | 9篇 |
1999年 | 21篇 |
1998年 | 18篇 |
1997年 | 8篇 |
1996年 | 20篇 |
1995年 | 18篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 6篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 9篇 |
1982年 | 15篇 |
1981年 | 22篇 |
1980年 | 24篇 |
1979年 | 26篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1975年 | 5篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1971年 | 7篇 |
1970年 | 4篇 |
排序方式: 共有2138条查询结果,搜索用时 857 毫秒
91.
IntroductionHarm perceptions about tobacco products may influence initiation, continued use, and cessation efforts. We assessed associations between adult traditional tobacco product use and absolute harm perceptions of traditional and alternative tobacco products. We also described the topics individuals looked for during their last search for information, their beliefs about chemicals in cigarettes/cigarette smoke, and how both relate to harm perceptions.MethodsWe ran multivariable models with jackknife replicate weights to analyze data from the 2015 administration of the National Cancer Institute's Health Information National Trends Survey (N = 3376).ResultsCompared to never users, individuals reported lower perceived levels of harm for products they use. Among current tobacco users, ethnicity, thinking about chemicals in tobacco, and information-seeking were all factors associated with tobacco product harm perceptions. In the full sample, some respondents reported searching for information about health effects and cessation and held misperceptions about the source of chemicals in tobacco.ConclusionsThis study fills a gap in the literature by assessing the absolute harm perceptions of a variety of traditional and alternative tobacco products. Harm perceptions vary among tobacco products, and the relationship among tobacco use, information seeking, thoughts about chemicals in tobacco products, and harm perceptions is complex. Data suggest that some individuals search for information about health effects and cessation and hold misperceptions about chemicals in tobacco products. Future inquiry could seek to understand the mechanisms that contribute to forming harm perceptions and beliefs about chemicals in tobacco products. 相似文献
92.
93.
Brandon P. Verdoorn MD Tamara K. Evans BS Gregory J. Hanson MD Yi Zhu PhD Larissa G. P. Langhi Prata PhD Robert J. Pignolo MD PhD Elizabeth J. Atkinson MS Erin O. Wissler-Gerdes MA George A. Kuchel MD Joan B. Mannick MD Stephen B. Kritchevsky PhD Sundeep Khosla MD Stacey A. Rizza MD Jeremy D. Walston MD Nicolas Musi MD Lewis A. Lipsitz MD Douglas P. Kiel MD Raymond Yung MB ChB Nathan K. LeBrasseur PhD Ravinder J. Singh PhD Teresa McCarthy MD MS Michael A. Puskarich MD Laura J. Niedernhofer MD PhD Paul D. Robbins PhD Matthew Sorenson JD MA Tamara Tchkonia PhD James L. Kirkland MD PhD 《Journal of the American Geriatrics Society》2021,69(11):3023-3033
The burden of senescent cells (SnCs), which do not divide but are metabolically active and resistant to death by apoptosis, is increased in older adults and those with chronic diseases. These individuals are also at the greatest risk for morbidity and mortality from SARS-CoV-2 infection. SARS-CoV-2 complications include cytokine storm and multiorgan failure mediated by the same factors as often produced by SnCs through their senescence-associated secretory phenotype (SASP). The SASP can be amplified by infection-related pathogen-associated molecular profile factors. Senolytic agents, such as Fisetin, selectively eliminate SnCs and delay, prevent, or alleviate multiple disorders in aged experimental animals and animal models of human chronic diseases, including obesity, diabetes, and respiratory diseases. Senolytics are now in clinical trials for multiple conditions linked to SnCs, including frailty; obesity/diabetes; osteoporosis; and cardiovascular, kidney, and lung diseases, which are also risk factors for SARS-CoV-2 morbidity and mortality. A clinical trial is underway to test if senolytics decrease SARS-CoV-2 progression and morbidity in hospitalized older adults. We describe here a National Institutes of Health-funded, multicenter, placebo-controlled clinical trial of Fisetin for older adult skilled nursing facility (SNF) residents who have been, or become, SARS-CoV-2 rtPCR-positive, including the rationale for targeting fundamental aging mechanisms in such patients. We consider logistic challenges of conducting trials in long-term care settings in the SARS-CoV-2 era, including restricted access, consent procedures, methods for obtaining biospecimens and clinical data, staffing, investigational product administration issues, and potential solutions for these challenges. We propose developing a national network of SNFs engaged in interventional clinical trials. 相似文献
94.
Abdulla A. Damluji Shang-En Chung Qian-Li Xue Rani K. Hasan Jeremy D. Walston Daniel E. Forman Karen Bandeen-Roche Mauro Moscucci Wayne Batchelor Jon R. Resar Gary Gerstenblith 《The American journal of medicine》2021,134(5):662-671.e1
BackgroundFrailty, a clinical state of vulnerability, is associated with subsequent adverse geriatric syndromes in the general population. We examined the long-term impact of frailty on geriatric outcomes among older patients with coronary heart disease.MethodsWe used the National Health and Aging Trends Study, a prospective cohort study linked to a Medicare sample. Coronary heart disease was identified by self-report or International Classification of Diseases (ICD) codes 1-year prior to the baseline visit. Frailty was measured using the Fried physical frailty phenotype. Geriatric outcomes were assessed annually during a 6-year follow-up.ResultsOf the 4656 participants, 1213 (26%) had a history of coronary heart disease 1-year prior to their baseline visit. Compared to those without frailty, subjects with frailty were older (ages ≥75: 80.9% vs 68.9%, P < 0.001), more likely to be female, and belong to an ethnic minority. The prevalence of hypertension, stroke, falls, disability, anxiety/depression, and multimorbidity were much higher in the frail, than nonfrail, participants. In a discrete time survival model, the incidence of geriatric syndromes during 6-year follow-up including 1) dementia, 2) loss of independence, 3) activities of daily living disability, 4) instrumental activities of daily living disability, and 5) mobility disability were significantly higher in the frail than in the nonfrail older patients with coronary heart disease.ConclusionIn patients with coronary heart disease, frailty is a risk factor for the accelerated development of geriatric outcomes. Efforts to identify frailty in the context of coronary heart disease are needed, as well as interventions to limit or reverse frailty status for older patients with coronary heart disease. 相似文献
95.
96.
97.
Maryam Alizadeh Dean X. Parmelee Elizabeth Peyton Neda Mehrdad Leila Janani 《Teaching and learning in medicine》2018,30(1):76-83
Problem: Studies on leadership identity development through reflection with Team-Based Learning (TBL) in medical student education are rare. We assumed that reflection and feedback on the team leadership process would advance the progression through leadership identity development stages in medical students within the context of classes using TBL. Intervention: This study is a quasi-experimental design with pretest–posttest control group. The pretest and posttest were reflection papers of medical students about their experience of leadership during their TBL sessions. In the intervention group, TBL and a team-based, guided reflection and feedback on the team leadership process were performed at the end of all TBL sessions. In the other group, only TBL was used. The Stata 12 software was used. Leadership Identity was treated both as a categorical and quantitative variable to control for differences in baseline and gender variables. Chi-square, t tests, and linear regression analysis were performed. Context: The population was a cohort of 2015–2016 medical students in a TBL setting at Tehran University of Medical Sciences, School of Medicine. Teams of four to seven students were formed by random sorting at the beginning of the academic year (intervention group n = 20 teams, control group n = 19 teams). Outcome: At baseline, most students in both groups were categorized in the Awareness and Exploration stage of leadership identity: 51 (52%) in the intervention group and 59 (55%) in the control group: uncorrected χ2(3) = 15.6, design-based F(2.83, 108) = 4.87, p = .003. In the posttest intervention group, 36 (36%) were in exploration, 33 (33%) were in L-identified, 20 (20%) were in Leadership Differentiated, and 10 (10%) were in the Generativity. None were in the Awareness or Integration stages. In the control group, 3 (20%) were in Awareness, 56 (53%) were in Exploration, 35 (33%) were in Leader Identified, 13 (12%) were in Leadership Differentiated. None were in the Generativity and Integration stages. Our hypothesis was supported by the data: uncorrected χ2(4) = 18.6, design-based F(3.77, 143) = 4.46, p = .002. The mean of the leadership identity in the pretest, intervention group equaled 1.93 (SD = 0.85) and the pretest, control group mean was 2.36 (SD = 0.86), p = .004. The mean of the posttest, intervention group was 3.04 (SD = 0.98) and posttest, control group mean was 2.54 (SD = 0.74), T = ?4.00, design df = 38, p < .001, and adjusted on baseline and gender T = ?8.97, design df = 38, p < .001. Lessons Learned: Reflection and feedback on the team leadership process in TBL advances the progression in stages of leadership identity development in medical students. Although the TBL strategy itself could have an impact on leadership identity development, this study demonstrates that when a reflection and feedback on leadership intervention are added, there is much greater impact. 相似文献
98.
Brendan R. Jackson Monique Salter Cheryl Tarr Amanda Conrad Emily Harvey Lisa Steinbock Amy Saupe Alida Sorenson Lee Katz Steven Stroika Kelly A. Jackson Heather Carleton Zuzana Kucerova David Melka Errol Strain Mickey Parish Rajal K. Mody 《MMWR. Morbidity and mortality weekly report》2015,64(10):282-283
99.
《Vaccine》2015,33(8):1021-1026
BackgroundThe Palestinian-Israeli Collaborative Research (PICR) cross-conflict setting provided a unique opportunity to study overall and indirect effects of pneumococcal conjugate vaccine (PCV7), in two closely related Palestinian populations governed by two distinct health authorities with distinct vaccination policies. Here, PCV7 effects on pneumococcal carriage, serotype distribution and antibiotic resistance are reported.MethodsAnnual cross-sectional surveys of pneumococcal carriage were performed during 2009–2011 among Palestinian children (≤5 years) (a) under Palestinian-Authority (PA) health policy (Ramallah, Nablus and Bethlehem), where PCV7 was unlicensed (b) under Israeli health policy (East-Jerusalem (EJ)) where PCV7 was rapidly implemented from July 2009. Clinical data were collected, pneumococci identified and characterized for antibiotic susceptibilities and serotype. Analyses included multivariate logistic models with an interaction term for PCV7-effect.ResultsAltogether, 2755 children from PA (n = 1772) and EJ (n = 983) were enrolled, of which ∼30% were pneumococcal carriers. While overall carriage was not affected by vaccination policy, carriage of vaccine-type (VT7) strains decreased from 52% to 22% (p < 0.001) in EJ, where PCV was implemented, but not in PA. This was accompanied by an increase in non-VT13 strains from 34% to 65% (p < 0.001) in EJ, but not in PA. Furthermore, within two years post-PCV7 introduction, proportion of multi-drug resistant strains, which was initially 23% in both populations, decreased significantly in EJ, to 10%, while simultaneously it increased in PA to 33% (p < 0.001). Similar trends were observed for resistance to most antibiotic groups. The proportion of resistant isolates among non-VT13 strains did not change during the study period.ConclusionsThe unique study design distinguishes secular and seasonal effects from true vaccine effects. While PCV7 did not affect overall pneumococcal carriage rate, VT7 strains, many of which were antibiotic resistant decreased and were replaced by non-VT13 strains, which were mostly not antibiotic resistant, resulting in a net decrease in antibiotic resistance. 相似文献
100.
《Archives of physical medicine and rehabilitation》2018,99(6):1067-1076
ObjectivesTo determine the association between patients' functional status at discharge from inpatient rehabilitation and 30-day potentially preventable hospital readmissions. A secondary objective was to examine the conditions resulting in these potentially preventable readmissions.DesignRetrospective cohort study.SettingInpatient rehabilitation facilities submitting claims to Medicare.ParticipantsNational cohort (N=371,846) of inpatient rehabilitation discharges among aged Medicare fee-for-service beneficiaries in 2013 to 2014. The average age was 79.1±7.6 years. Most were women (59.7%) and white (84.5%).InterventionsNot applicable.Main Outcome Measures(1) Observed rates and adjusted odds of 30-day potentially preventable hospital readmissions after inpatient rehabilitation and (2) primary diagnoses for readmissions.ResultsThe overall rate of any 30-day hospital readmission after inpatient rehabilitation was 12.4% (n=46,265), and the overall rate of potentially preventable readmissions was 5.0% (n=18,477). Functional independence was associated with lower observed rates and adjusted odds ratios for potentially preventable readmissions. Observed rates for the highest versus lowest quartiles within each functional domain were as follows: self-care: 3.4% (95% confidence interval [CI], 3.3–3.5) versus 6.9% (95% CI, 6.7–7.1), mobility: 3.3% (95% CI, 3.2–3.4) versus 7.2% (95% CI, 7.0–7.4), and cognition: 3.5% (95% CI, 3.4–3.6) versus 6.2% (95% CI, 6.0–6.4), respectively. Similarly, adjusted odds ratios were as follows: self-care: .70 (95% CI, .67–.74), mobility: .64 (95% CI, .61–.68), and cognition: .84 (95% CI, .80–.89). Infection-related conditions (44.1%) were the most common readmission diagnoses followed by inadequate management of chronic conditions (31.2%) and inadequate management of other unplanned events (24.7%).ConclusionsFunctional status at discharge from inpatient rehabilitation was associated with 30-day potentially preventable readmissions in our sample of aged Medicare beneficiaries. This information may help identify at-risk patients. Future research is needed to determine whether follow-up programs focused on improving functional independence will reduce readmission rates. 相似文献