全文获取类型
收费全文 | 8136篇 |
免费 | 630篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 278篇 |
妇产科学 | 267篇 |
基础医学 | 1017篇 |
口腔科学 | 126篇 |
临床医学 | 1135篇 |
内科学 | 1422篇 |
皮肤病学 | 133篇 |
神经病学 | 739篇 |
特种医学 | 194篇 |
外科学 | 822篇 |
综合类 | 61篇 |
一般理论 | 16篇 |
预防医学 | 1096篇 |
眼科学 | 113篇 |
药学 | 603篇 |
中国医学 | 13篇 |
肿瘤学 | 689篇 |
出版年
2024年 | 17篇 |
2023年 | 99篇 |
2022年 | 105篇 |
2021年 | 235篇 |
2020年 | 200篇 |
2019年 | 245篇 |
2018年 | 262篇 |
2017年 | 216篇 |
2016年 | 258篇 |
2015年 | 255篇 |
2014年 | 316篇 |
2013年 | 468篇 |
2012年 | 664篇 |
2011年 | 734篇 |
2010年 | 366篇 |
2009年 | 297篇 |
2008年 | 553篇 |
2007年 | 541篇 |
2006年 | 543篇 |
2005年 | 501篇 |
2004年 | 373篇 |
2003年 | 408篇 |
2002年 | 362篇 |
2001年 | 69篇 |
2000年 | 42篇 |
1999年 | 64篇 |
1998年 | 66篇 |
1997年 | 47篇 |
1996年 | 49篇 |
1995年 | 35篇 |
1994年 | 41篇 |
1993年 | 31篇 |
1992年 | 36篇 |
1991年 | 16篇 |
1990年 | 29篇 |
1989年 | 20篇 |
1988年 | 15篇 |
1987年 | 14篇 |
1986年 | 18篇 |
1984年 | 9篇 |
1983年 | 16篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 9篇 |
1979年 | 15篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1975年 | 8篇 |
1974年 | 15篇 |
1973年 | 8篇 |
排序方式: 共有8789条查询结果,搜索用时 31 毫秒
941.
van der Steen JT Lane P Kowall NW Knol DL Volicer L 《Journal of the American Medical Directors Association》2012,13(2):156-161
ObjectivesTo describe long-term mortality rate and to assess associations between mortality rate and antibiotic treatment of lower respiratory infection in patients with advanced dementia; antibiotic treatment allocation was independent of mortality risk—leaving less room for biased associations than in previous multicenter observational studies.DesignProspective study (2004–2009). Multilevel Cox proportional hazard analyses with adjustment for mortality risk were used to assess associations between antibiotics and mortality using time-dependent covariates.SettingA US Department of Veterans Affairs nursing home.ParticipantsNinety-four residents with advanced dementia who developed 109 episodes.MeasurementsSurvival, treatment, mortality risk, illness severity, fluid intake, and several other patient characteristics.ResultsTen-day mortality was 48%, and 6-month mortality was 74%. Antibiotics were used in 77% of episodes. Overall, antibiotics were not associated with mortality rate (Hazard Ratio [HR] 0.70, Confidence Interval [CI] 0.38–1.30); however, antibiotics were associated with reduced 10-day mortality rate (HR 0.51, CI, 0.30–0.87; rate after 10 days: 1.5, CI 0.42–5.2). Benefit from antibiotics was less likely with inadequate fluid intake, and when experiencing the first episode.ConclusionIn our sample of male nursing home residents with advanced dementia and lower respiratory infection, mortality was substantial despite antibiotic treatment. Antibiotics prolonged life but in many cases only for several days. Treatment decisions should take into account that antibiotics may delay death but may also prolong the dying process, indicating a need for accurate prediction of mortality and study of characteristics that may alter effectiveness of antibiotics. 相似文献
942.
van Buul LW van der Steen JT Veenhuizen RB Achterberg WP Schellevis FG Essink RT van Benthem BH Natsch S Hertogh CM 《Journal of the American Medical Directors Association》2012,13(6):568.e1-568.13
IntroductionThe common occurrence of infectious diseases in nursing homes and residential care facilities may result in substantial antibiotic use, and consequently antibiotic resistance. Focusing on these settings, this article aims to provide a comprehensive overview of the literature available on antibiotic use, antibiotic resistance, and strategies to reduce antibiotic resistance.MethodsRelevant literature was identified by conducting a systematic search in the MEDLINE and EMBASE databases. Additional articles were identified by reviewing the reference lists of included articles, by searching Google Scholar, and by searching Web sites of relevant organizations.ResultsA total of 156 articles were included in the review. Antibiotic use in long term care facilities is common; reported annual prevalence rates range from 47% to 79%. Part of the prescribed antibiotics is potentially inappropriate.The occurrence of antibiotic resistance is substantial in the long term care setting. Risk factors for the acquisition of resistant pathogens include prior antibiotic use, the presence of invasive devices, such as urinary catheters and feeding tubes, lower functional status, and a variety of other resident- and facility-related factors. Infection with antibiotic-resistant pathogens is associated with increased morbidity, mortality, and health care costs.Two general strategies to reduce antibiotic resistance in long term care facilities are the implementation of infection control measures and antibiotic stewardship.ConclusionThe findings of this review call for the conduction of research and the development of policies directed at reducing antibiotic resistance and its subsequent burden for long term care facilities and their residents. 相似文献
943.
Levison J Williams LT Moore A McFarlane J Davila JA 《Maternal and child health journal》2012,16(9):1748-1753
Although, the Centers for Disease Control and the American College of Obstetricians and Gynecologists have advised rapid HIV testing for laboring women of unknown human immunodeficiency virus (HIV) status since 2004 to ensure that results are known prior to delivery, physicians and hospital staff have been slow to follow the recommendation. A multi-component intervention was implemented to educate physicians and hospital staff. There was low baseline knowledge (<50% correct) in the areas of HIV prevalence, use of rapid testing in the prevention of perinatal HIV transmission, and treatment. On 9 out of 14 items, participants demonstrated a >35% increase in correct responses from pre-test to 3?month post-test. Baseline knowledge among obstetric health care providers about how to diagnose and treat newly diagnosed pregnant women was low. Brief exposure to an educational program yielded a marked increase in knowledge that was sustained over 3?months. Educating health professionals in obstetrics and gynecology regarding rapid human immunodeficiency virus (HIV) testing in Labor and Delivery: A local initiative. 相似文献
944.
Jo Ann S. Carson Linda Michalsky Bernadette Latson Kamakki Banks Liyue Tong Nora Gimpel Jenny J. Lee Mark J. DeHaven 《Journal of the Academy of Nutrition and Dietetics》2012,112(11):1852-1858
African Americans have a higher incidence of cardiovascular disease (CVD) than Americans in general and are thus prime targets for efforts to reduce CVD risk. Dietary intake data were obtained from African Americans participating in the Genes, Nutrition, Exercise, Wellness, and Spiritual Growth (GoodNEWS) Trial. The 286 women and 75 men who participated had a mean age of 49 years; 53% had hypertension, 65% had dyslipidemia, and 51% met criteria for metabolic syndrome. Their dietary intakes were compared with American Heart Association and National Heart, Lung, and Blood Institute nutrition parameters to identify areas for improvement to reduce CVD risk in this group of urban church members in Dallas, TX. Results from administration of the Dietary History Questionnaire indicated median daily intakes of 33.6% of energy from total fat, 10.3% of energy from saturated fat, 171 mg cholesterol, 16.3 g dietary fiber, and 2,453 mg sodium. A beneficial median intake of 2.9 cups fruits and vegetables per day was coupled with only 2.7 oz fish/week and an excessive intake of 13 tsp added sugar/day. These data indicate several changes needed to bring the diets of these individuals—and likely many other urban African Americans—in line with national recommendations, including reduction of saturated fat, sodium, and sugar intake, in addition to increased intake of fatty fish and whole grains. The frequent inclusion of vegetables should be encouraged in ways that promote achievement of recommended intakes of energy, fat, fiber, and sodium. 相似文献
945.
Kaulmann A Serchi T Renaut J Hoffmann L Bohn T 《The British journal of nutrition》2012,108(6):963-973
Carotenoid consumption has been linked to a number of beneficial health effects, including the reduction of chronic diseases such as cancer and cardiovascular complications. However, no data are available on their action on the intestinal epithelium, being exposed to the highest concentrations of carotenoids in the human body, and where they could act preventively on intestinal inflammatory diseases such as Crohn's disease and ulcerative colitis. The objective of the present study was to investigate whether lycopene and β-carotene in micelles (M), at concentrations that could be reached via the diet (10-25?μg/ml) could aid in the reduction of TNF-α plus IL-1β-induced inflammation of Caco-2 human epithelial cells. The impact on biomarkers of inflammation, including IL-8, NO and cyclo-oxygenase-2 (through PGE-2α), and the NF-κB and mitogen-activated protein kinase (MAPK) pathways of intracellular signalling cascades were evaluated compared with controls (empty M). Furthermore, proteomic analyses were conducted from total cellular protein extracts. The results revealed that isolated carotenoids had no statistical significant anti-inflammatory effect on the biomarkers observed, or on the regulation of NF-κB and MAPK. Nevertheless, analyses of the proteome suggested that fifteen proteins were significantly (P?0·05, expression ratio >1·3) differentially regulated following β-carotene exposure, participating mostly in metabolic activities including antioxidant mechanisms, such as glutathione S-transferase A1. Only one protein was differentially regulated by lycopene (profilin-1). To our knowledge, this is the first attempt to investigate pathways involved in the action of carotenoids on the intestinal epithelium. 相似文献
946.
947.
This paper investigates whether cannabis use affects physical and mental health. To do so, information on prime aged individuals living in Amsterdam in 1994 is used. Dutch data offer a clear advantage in estimating the health impacts of cannabis use because the legal status of cannabis in the Netherlands ensures that estimates are free from confounding with the physical and psychological effects of engaging in a criminal activity. Accounting for selection into cannabis use and shared frailties in mental and physical health, the results suggest that cannabis use reduces the mental wellbeing of men and women and the physical wellbeing of men. Although statistically significant, the magnitude of the effect of using cannabis on mental and physical health is found to be small. 相似文献
948.
Vesikari T Forstén A Herbinger KH Cioppa GD Beygo J Borkowski A Groth N Bennati M von Sonnenburg F 《Vaccine》2012,30(7):1388-1396
Background
The potential consequences of an avian influenza pandemic warrants the development of safe, highly immunogenic pre-pandemic A/H5N1 vaccines with cross-clade protection. In this randomized, controlled study we compared the immunogenicity and safety of an MF59®-adjuvanted (Novartis Vaccines, Marburg, Germany) A/H5N1 pre-pandemic vaccine with that of a licensed, MF59-adjuvanted, seasonal influenza vaccine.Methods
Healthy adult (18–60 years, n = 3372) and elderly (≥61 years, n = 275) volunteers received either an initial dose of a licensed, non-adjuvanted, trivalent, seasonal influenza vaccine (Agrippal®) on Day 1, followed by one dose of MF59-H5N1 study vaccine on Day 22 and a second dose of MF59-H5N1 on Day 43, or alternatively, placebo on Day 1 followed by one dose of MF59-adjuvanted seasonal reference vaccine on Day 22 and a second dose of reference vaccine on Day 43. Homologous and cross-reactive A/H5N1 antibody responses were analysed by haemagglutination inhibition (HI), single radial haemolysis (SRH), and microneutralization (MN) assays three weeks after each vaccination. Vaccine safety was assessed throughout the study.Results
Analysis by HI assay found that two doses of MF59-H5N1 resulted in a seroconversion rate of 56% and a geometric mean ratio (GMR) of 7.1 in adult subjects. Similar results were observed on analysis by SRH (GMR 4.03; seroconversion 78% and seroprotection 91%) and MN (seroconversion 67%) assays. These data met the European licensure criteria for influenza vaccines. No significant difference in immunogenicity was detected between the adult and elderly populations. Anti-A/H5N1 cross-clade antibodies were detected by SRH, 49% of adult and 32% of elderly subjects achieved seroconversion after the second vaccine dose. Overall, MF59-H5N1 containing 7.5 μg antigen was less reactogenic than the MF59-adjuvanted trivalent seasonal vaccine which contained 15 μg antigen for each component strain.Conclusions
Two doses of MF59-H5N1 vaccine were well tolerated and induced adequate levels of seroprotection against homologous and cross-clade A/H5N1 virus. These data support the suitability of MF59-adjuvanted A/H5N1 vaccine for pre-pandemic use in adults and the elderly. 相似文献949.
Ingram JC Deave T Towner E Errington G Kay B Kendrick D 《Health education research》2012,27(2):258-268
Injuries are the leading cause of childhood death internationally; steep social gradients exist in mortality and morbidity. The majority of pre-school injuries occur in the home, but implementing research into practice for injury prevention has received little attention. This systematic review describes key facilitators and barriers when implementing injury prevention interventions. The review used articles included in a Cochrane systematic review of the effectiveness of home safety education, with or without the provision of safety equipment. Each paper was screened to ensure that children under 5 years, intervention details and process measures and/or barriers and facilitators were included. Two authors independently reviewed each paper and extracted data. Themes were identified and framework analysis used in an iterative process. Ninety-nine papers were identified, 42 excluded and 57 included in the analysis. Seven facilitators and six barriers were identified. Facilitators related to the approach used, focused messages, minimal changes, deliverer characteristics, equipment accessibility, behaviour change and including incentives. The barriers included complex interventions, cultural, socio-economic, physical and behavioural barriers and deliverer constraints. Barriers and facilitators should be addressed when implementing injury prevention interventions and studies should explicitly explore factors that help or hinder the process. 相似文献
950.