全文获取类型
收费全文 | 84351篇 |
免费 | 5031篇 |
国内免费 | 307篇 |
专业分类
耳鼻咽喉 | 1211篇 |
儿科学 | 2456篇 |
妇产科学 | 1558篇 |
基础医学 | 9601篇 |
口腔科学 | 1667篇 |
临床医学 | 8039篇 |
内科学 | 18044篇 |
皮肤病学 | 1313篇 |
神经病学 | 8256篇 |
特种医学 | 3151篇 |
外国民族医学 | 5篇 |
外科学 | 14023篇 |
综合类 | 883篇 |
一般理论 | 95篇 |
预防医学 | 6505篇 |
眼科学 | 1491篇 |
药学 | 5434篇 |
12篇 | |
中国医学 | 127篇 |
肿瘤学 | 5818篇 |
出版年
2023年 | 489篇 |
2022年 | 779篇 |
2021年 | 2054篇 |
2020年 | 1118篇 |
2019年 | 1762篇 |
2018年 | 2061篇 |
2017年 | 1501篇 |
2016年 | 1560篇 |
2015年 | 1707篇 |
2014年 | 2636篇 |
2013年 | 3673篇 |
2012年 | 5522篇 |
2011年 | 5801篇 |
2010年 | 3171篇 |
2009年 | 2828篇 |
2008年 | 5081篇 |
2007年 | 5373篇 |
2006年 | 5156篇 |
2005年 | 5107篇 |
2004年 | 4809篇 |
2003年 | 4440篇 |
2002年 | 4149篇 |
2001年 | 955篇 |
2000年 | 896篇 |
1999年 | 1055篇 |
1998年 | 885篇 |
1997年 | 771篇 |
1996年 | 700篇 |
1995年 | 603篇 |
1994年 | 596篇 |
1993年 | 509篇 |
1992年 | 652篇 |
1991年 | 637篇 |
1990年 | 576篇 |
1989年 | 539篇 |
1988年 | 476篇 |
1987年 | 431篇 |
1986年 | 463篇 |
1985年 | 576篇 |
1984年 | 563篇 |
1983年 | 466篇 |
1982年 | 603篇 |
1981年 | 544篇 |
1980年 | 500篇 |
1979年 | 319篇 |
1978年 | 319篇 |
1977年 | 324篇 |
1976年 | 265篇 |
1975年 | 276篇 |
1973年 | 243篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Annette E Hay Nicole Mittmann Michael Crump Matthew C Cheung Jessica Sleeth Judy Needham Mike Broekhoven Marina Djurfeldt Lois E Shepherd Ralph M Meyer Bingshu E Chen Joseph L Pater 《Current oncology (Toronto, Ont.)》2021,28(2):1153
In a prospective study, we sought to determine acceptability of linkage of administrative and clinical trial data among Canadian patients and Research Ethics Boards (REBs). The goal is to develop a more harmonized approach to data, with potential to improve clinical trial conduct through enhanced data quality collected at reduced cost and inconvenience for patients. On completion of the original LY.12 randomized clinical trial in lymphoma (), participants were invited to enrol in the Long-term Innovative Follow-up Extension (LIFE) component. Those consenting to do so provided comprehensive identifying information to facilitate linkage with their administrative data. We prospectively designed a global assessment of this innovative approach to clinical trial follow-up including rates of REB approval and patient consent. The pre-specified benchmark for patient acceptability was 80%. Of 16 REBs who reviewed the research protocol, 14 (89%) provided approval; two in Quebec declined due to small patient numbers. Of 140 patients invited to participate, 115 (82%, 95% CI 76 to 88%) from across 9 Canadian provinces provided consent and their full name, date of birth, health insurance number and postal code to facilitate linkage with their administrative data for long-term follow-up. Linkage of clinical trial and administrative data is feasible and acceptable. Further collaborative work including many stakeholders is required to develop an optimized secure approach to research. A more coordinated national approach to health data could facilitate more rapid testing and identification of new effective treatments across multiple jurisdictions and diseases from diabetes to COVID-19. NCT00078949相似文献
12.
Sarah J. Schrauben Haochang Shou Xiaoming Zhang Amanda Hyre Anderson Joseph V. Bonventre Jing Chen Steven Coca Susan L. Furth Jason H. Greenberg Orlando M. Gutierrez Joachim H. Ix James P. Lash Chirag R. Parikh Casey M. Rebholz Venkata Sabbisetti Mark J. Sarnak Michael G. Shlipak Sushrut S. Waikar Paul L. Kimmel Ramachandran S. Vasan Harold I. Feldman Jeffrey R. Schelling 《Journal of the American Society of Nephrology : JASN》2021,32(1):115
13.
Eyal Schwartzberg Joseph P. Nathan Sivan Avron Eli Marom 《Israel journal of health policy research》2018,7(1):59
The community pharmacy setting is a venue that is readily accessible to the public. In addition, it is staffed by a pharmacist, who is a healthcare provider, trained and capable of delivering comprehensive pharmaceutical care. As such, community pharmacists have a colossal opportunity to serve as key contributors to patients’ health by ensuring appropriate use of medications, preventing medication misadventures, identifying drug-therapy needs, as well as by being involved in disease management, screening, and prevention programs. This unique position gives the pharmacist the privilege and duty to serve patients in roles other than solely that of the stereotypical drug dispenser.Worldwide, as well as in Israel, pharmacists already offer a variety of pharmaceutical services and tend to patients’ and the healthcare system’s needs. This article provides examples of professional, clinical or other specialty services offered by community pharmacists around the world and in Israel and describes these interventions as well as the evidence for their efficacy. Examples of such activities which were recently introduced to the Israeli pharmacy landscape due to legislative changes which expanded the pharmacist’s scope of practice include emergency supply of medications, pharmacists prescribing, and influenza vaccination. Despite the progress already made, further expansion of these opportunities is warranted but challenging. Independent prescribing, as practiced in the United Kingdom or collaborative drug therapy management programs, as practiced in the United States, expansion of vaccination programs, or wide-spread recognition and reimbursement for medication therapy management (MTM) programs are unrealized opportunities. Obstacles such as time constraints, lack of financial incentives, inadequate facilities and technology, and lack of professional buy-in, and suggested means for overcoming these challenges are also discussed. 相似文献
14.
Joseph J. Knapik Krista G. Austin Emily K. Farina Harris R. Lieberman 《Journal of the Academy of Nutrition and Dietetics》2018,118(8):1370-1388
Background
Dietary supplement (DS) use is prevalent among the US Armed Forces personnel, but representative cross-service comparisons and characteristics of personnel using DSs are limited.Objective
Examine DS use and characteristics associated with use in a representative sample of US Armed Forces personnel (Army, Navy, Air Force, Marine Corps, and Coast Guard) using data from the 2011 Department of Defense Survey of Health-Related Behaviors.Design and participants
A stratified random sample of service members (SMs) was contacted and asked to complete a questionnaire assessing personal characteristics and DS use.Results
Overall, 69% of the 39,877 SMs reported using DSs ≥1 time per week. The most commonly used DSs were multivitamin or multiminerals (50%), antioxidants (34%), individual vitamins or minerals (33%), bodybuilding supplements (27%), fish oils (26%), herbals (16%), and weight-loss supplements (16%). Multiple logistic regression indicated overall DS use was higher among women, those with higher educational levels, Marine Corps SMs, officers, those with higher body mass index, those engaged in greater physical activity and weight training, and people in weight control programs. DS use was lower when peer groups or leadership discouraged substance abuse.Conclusions
DS use was considerably higher in the US Armed Forces compared with civilian populations, although many demographic and lifestyle factors associated with use were similar. Some categories of DSs extensively used by SMs such as bodybuilding supplements have been associated with adverse events. Discouraging substance abuse through peer groups and leadership actions may reduce use of unnecessary or dangerous DSs. 相似文献15.
Novel cardiovascular magnetic resonance oxygenation approaches in understanding pathophysiology of cardiac diseases 下载免费PDF全文
Karthigesh Sree Raman Gaetano Nucifora Joseph B Selvanayagam 《Clinical and experimental pharmacology & physiology》2018,45(5):475-480
Cardiovascular magnetic resonance imaging (CMR) permits accurate phenotyping of many cardiac diseases. CMR’s inherent advantages are its non‐invasive nature, lack of ionizing radiation and high accuracy and reproducibility. Furthermore, it is able to assess many aspects of cardiac anatomy, structure and function. Specifically, it can characterize myocardial tissue, myocardial function, myocardial mass, myocardial blood flow/perfusion, irreversible and reversible injury, all with a high degree of accuracy and reproducibility. Hence, CMR is a powerful tool in clinical and pre‐clinical research. In recent years there have been novel advances in CMR myocardial tissue characterization. Oxygenation‐sensitive CMR (OS‐CMR) is a novel non‐invasive, contrast independent technique that permits direct quantification of myocardial tissue oxygenation, both at rest and during stress. In this review, we will address the principles of the OS‐CMR technique, its recent advances and summarize the studies in the effects of oxygenation on cardiac diseases. 相似文献
16.
Julie Ann Justo P. Brandon Bookstaver Joseph Kohn Helmut Albrecht Majdi N. Al-Hasan 《International journal of antimicrobial agents》2018,51(3):488-492
The utility of empirical combination antimicrobial therapy for Gram-negative bloodstream infection (BSI) remains unclear. This retrospective, quasi-experimental matched cohort study examined the impact of empirical combination therapy on mortality in patients with Gram-negative BSI. Hospitalized adults with Gram-negative BSI from 1 January 2010 to 31 December 2013 at Palmetto Health Hospitals in Columbia, SC, USA were identified. Patients receiving combination therapy or beta-lactam monotherapy were matched 1:1 based on age, sex and Bloodstream Infection Mortality Risk Score (BSIMRS). Multivariate Cox proportional hazards regression with propensity score adjustment was used to examine overall 28–day mortality and within predefined BSIMRS categories (<5 and ≥5). A total of 380 patients receiving combination therapy or monotherapy for Gram-negative BSI were included in the study. Median age was 66 years and 204 (54%) were female. Overall, 28-day mortality in patients who received combination therapy and monotherapy was 13% and 15%, respectively (P?=?0.51). After stratification by BSIMRS, mortality in both combination therapy and monotherapy groups was 1.1% in patients with BSIMRS <5 (P?=?0.98) and 27% and 32%, respectively, in patients with BSIMRS ≥5 (P?=?0.47). After adjusting for propensity to receive combination therapy, risk of mortality was not significantly different for combination therapy compared to monotherapy (hazard ratio [HR] 0.90, 95% confidence interval [CI] 0.51–1.60). This finding persisted for both subgroups of BSIMRS <5 (HR 0.96, 95% CI 0.04–24.28) and BSIMRS ≥5 (HR 0.83, 95% CI 0.46–1.48). There is no survival benefit from empirical combination therapy over monotherapy in patients with Gram-negative BSI, regardless of predicted prognosis at initial presentation. 相似文献
17.
18.
Aaron Yarlas Martha Bayliss Joseph C. Cappelleri Stephen Maher Andrew G. Bushmakin Lea Ann Chen Alireza Manuchehri Paul Healey 《Quality of life research》2018,27(2):273-290
Purpose
To conduct a systematic literature review of the reliability, construct validity, and responsiveness of the SF-36® Health Survey (SF-36) in patients with ulcerative colitis (UC).Methods
We performed a systematic search of electronic medical databases to identify published peer-reviewed studies which reported scores from the eight scales and/or two summary measures of the SF-36 collected from adult patients with UC. Study findings relevant to reliability, construct validity, and responsiveness were reviewed.Results
Data were extracted and summarized from 43 articles meeting inclusion criteria. Convergent validity was supported by findings that 83% (197/236) of correlations between SF-36 scales and measures of disease symptoms, disease activity, and functioning exceeded the prespecified threshold (r ≥ |0.40|). Known-groups validity was supported by findings of clinically meaningful differences in SF-36 scores between subgroups of patients when classified by disease activity (i.e., active versus inactive), symptom status, and comorbidity status. Responsiveness was supported by findings of clinically meaningful changes in SF-36 scores following treatment in non-comparative trials, and by meaningfully larger improvements in SF-36 scores in treatment arms relative to controls in randomized controlled trials. The sole study of SF-36 reliability found evidence supporting internal consistency (Cronbach’s α ≥ 0.70) for all SF-36 scales and test–retest reliability (intraclass correlation coefficient ≥0.70) for six of eight scales.Conclusions
Evidence from this systematic literature review indicates that the SF-36 is reliable, valid, and responsive when used with UC patients, supporting the inclusion of the SF-36 as an endpoint in clinical trials for this patient population.19.
Arsenic association with circulating oxidized low-density lipoprotein in a Native American community
Molly E. Harmon Johnnye Lewis Curtis Miller Joseph Hoover Abdul-Mehdi S. Ali Chris Shuey 《Journal of toxicology and environmental health. Part A》2018,81(13):535-548
More than 500 abandoned uranium (U) mines within the Navajo Nation contribute U, arsenic (As) and other metals to groundwater, soil and potentially air through airborne transport. The adverse cardiovascular health effects attributed to cumulative exposure to these metals remains uncertain. The aim of this study was to examine whether environmental exposure to these metals may promote or exacerbate the oxidation of low-density lipoprotein (LDL) cholesterol in this Native American population. The correlation of cardiovascular biomarkers (oxidized LDL (oxLDL) and C-reactive protein (CRP)) from a Navajo cohort (n = 252) with mean annual As and U intakes from water and urine metals was estimated using linear regression. Proof-of-concept assays were performed to investigate whether As and U directly oxidize human LDL. Mean annual As intake from water was positively and significantly associated with oxLDL, but not CRP in this study population, while U intake estimates were negatively associated with oxLDL. In an acellular system, As, but not U, directly oxidized the apolipoprotein B-100 component of purified human LDL. Neither metal promoted lipid peroxidation of the LDL particle. Both the population and lab results are consistent with the hypothesis that As promotes oxidation of LDL, a crucial step in vascular inflammation and chronic vascular disease. Conversely, for outcomes related to U, negative associations were observed between U intake and oxLDL, and U only minimally altered human LDL in direct exposure experiments. Only urine U was correlated with CRP, whereas no other metals in water or urine were apparently reliable predictors of this inflammatory marker. 相似文献
20.
Joseph E. Jacher Nikita Roy Mohammad Ghaziuddin Jeffrey W. Innis 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2019,180(7):483-487
MBOAT7 gene pathogenic variants are a newly discovered and rare cause for intellectual disability, autism spectrum disorder (ASD), seizures, truncal hypotonia, appendicular hypertonia, and below average head sizes (ranging from ?1 to ?3 standard deviations). There have been only 16 individuals previously reported who have MBOAT7‐related intellectual disability, all of whom were younger than 10 years old and from consanguineous relationships. Thus, there is a lack of phenotypic information for adolescent and adult individuals with this disorder. Medical genetics and psychiatric evaluations in a 14‐year‐old female patient with a history of global developmental delay, intellectual disability, overgrowth with macrocephaly, metrorrhagia, seizures, basal ganglia hyperintensities, nystagmus, strabismus with amblyopia, ASD, anxiety, attention deficit hyperactivity disorder (ADHD), aggressive outbursts, and hyperphagia included a karyotype, methylation polymerase chain reaction for Prader‐Willi/Angelman syndrome, chromosome microarray, and whole exome sequencing (WES), ADOS2, and ADI‐R. WES identified a homozygous, likely pathogenic variant in the MBOAT7 gene (c.855‐2A>G). This is the oldest known patient with MBOAT7‐related intellectual disability, whose unique features compared with previously described individuals include overgrowth with macrocephaly, metrorrhagia, ophthalmological abnormalities, basal ganglia hyperintensities, unspecified anxiety disorder, and ADHD; combined type; and hyperphagia with the absence of appendicular hypertonia and cortical atrophy. More individuals need to be identified in order to delineate the full clinical spectrum of this disorder. 相似文献