全文获取类型
收费全文 | 2465822篇 |
免费 | 178044篇 |
国内免费 | 3716篇 |
专业分类
耳鼻咽喉 | 33826篇 |
儿科学 | 79683篇 |
妇产科学 | 65205篇 |
基础医学 | 363081篇 |
口腔科学 | 69711篇 |
临床医学 | 220125篇 |
内科学 | 482268篇 |
皮肤病学 | 54759篇 |
神经病学 | 195044篇 |
特种医学 | 91387篇 |
外国民族医学 | 508篇 |
外科学 | 368155篇 |
综合类 | 48551篇 |
现状与发展 | 12篇 |
一般理论 | 891篇 |
预防医学 | 195647篇 |
眼科学 | 56710篇 |
药学 | 181865篇 |
11篇 | |
中国医学 | 5067篇 |
肿瘤学 | 135076篇 |
出版年
2021年 | 21821篇 |
2019年 | 22072篇 |
2018年 | 30677篇 |
2017年 | 23032篇 |
2016年 | 25177篇 |
2015年 | 28537篇 |
2014年 | 40158篇 |
2013年 | 58946篇 |
2012年 | 82501篇 |
2011年 | 87722篇 |
2010年 | 51253篇 |
2009年 | 48160篇 |
2008年 | 80740篇 |
2007年 | 86071篇 |
2006年 | 86301篇 |
2005年 | 84046篇 |
2004年 | 80214篇 |
2003年 | 76943篇 |
2002年 | 73163篇 |
2001年 | 111083篇 |
2000年 | 113661篇 |
1999年 | 95535篇 |
1998年 | 27903篇 |
1997年 | 24430篇 |
1996年 | 24774篇 |
1995年 | 23374篇 |
1994年 | 21510篇 |
1993年 | 20332篇 |
1992年 | 73340篇 |
1991年 | 71410篇 |
1990年 | 69637篇 |
1989年 | 66892篇 |
1988年 | 61453篇 |
1987年 | 60192篇 |
1986年 | 56241篇 |
1985年 | 53985篇 |
1984年 | 40030篇 |
1983年 | 33991篇 |
1982年 | 20206篇 |
1979年 | 36407篇 |
1978年 | 25998篇 |
1977年 | 21513篇 |
1976年 | 20601篇 |
1975年 | 22161篇 |
1974年 | 26498篇 |
1973年 | 25154篇 |
1972年 | 23493篇 |
1971年 | 22312篇 |
1970年 | 20539篇 |
1969年 | 19586篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Debbie I. Craig Monica R. Lininger Heidi A. Wayment Ann H. Huffman 《Research in sports medicine (Print)》2020,28(2):181-193
ABSTRACTWhile research on sport-related concussion has increased dramatically over the past decade, research investigating concussion reporting is in its early stages. The purpose of this project was to assess concussion reporting and work with stakeholders to develop and assess strategies to improve reporting. We used a multi-site, repeated measures design with three NCAA Division I football programs, including 223 athlete participants. A modified community-based participatory research (CBPR) approach was used to develop intervention strategies (Fall 2017 season) with stakeholders designed to increase concussion reporting intentions. Preseason and postseason surveys were administered to determine effectiveness. Main outcome measures included concussion knowledge, intervention effectiveness, and reporting intention measures. For all three programs, concussion knowledge was unrelated to reporting intentions. Two of the three programs implemented the intervention strategies and for these programs there was evidence that the interventions were effective. Specifically, athletes from these two programs perceived more support from coaches about reporting (P< 0.05; t= 2.83), received education more frequently (P< 0.05; t= 2.67), and reported being more likely to report concussion symptoms (P< 0.05; t= 2.14). Our study demonstrates that working with stakeholders to develop site-specific strategies to improve concussion reporting is an effective approach to help improve reporting behaviours. 相似文献
62.
Benjamin Davido Rui Batista Aurélien Dinh Pierre de Truchis E.M. Terveer Bruce Roberts Ed J. Kuijper Silvia Caballero 《International journal of antimicrobial agents》2019,53(5):553-556
Background
Spontaneous decolonization of antibiotic-resistant bacteria (ARB) takes time: approximately 25% after 30 days for carbapenem-producing Enterobacteriaceae or extended-spectrum beta-lactamase-producing Enterobacteriaceae. Faecal microbiota transplantation (FMT) has been proposed as a new strategy to promote decolonization in order to reduce the risk of superinfection due to these ARB. This paper discusses the literature on the use of FMT for this indication, and the improvement levers available to promote its efficacy.Methods
Literature available to date concerning the use of FMT to eradicate ARB was reviewed, and the different factors that may have influenced the efficacy of decolonization were evaluated.Results
Four axes that could have played major roles in the efficacy of FMT were identified: bowel preparation before FMT; donor; dose; and thermal conditioning of faeces. The positive or negative impact of each on the outcome of FMT is discussed.Conclusion
Although FMT is very efficient for the eradication of Clostridium difficile, the same ‘recipe’ cannot be used for the eradication of ARB. Working together with expert centres may help to improve the efficacy of FMT for this indication, and enable the reduction of in-hospital isolation precautions. 相似文献63.
R.J. van de Peppel M.T. van der Beek L.G. Visser M.G.J. de Boer J. Wallinga 《International journal of antimicrobial agents》2019,53(3):284-293
Objectives
Triazole resistance in Aspergillus spp. is emerging and complicates prophylaxis and treatment of invasive aspergillosis (IA) worldwide. New polymerase chain reaction (PCR) tests on broncho-alveolar lavage (BAL) fluid allow for detection of triazole resistance at a genetic level, which has opened up new possibilities for targeted therapy. In the absence of clinical trials, a modelling study delivers estimates of the added value of resistance detection with PCR, and which empiric therapy would be optimal when local resistance rates are known.Design
A decision-analytic modelling study was performed based on epidemiological data of IA, extended with estimated dynamics of resistance rates and treatment effectiveness. Six clinical strategies were compared that differ in use of PCR diagnostics (used vs not used) and in empiric therapeutic choice in case of unknown triazole susceptibility: voriconazole, liposomal amphotericin B (LAmB) or both. Outcome measures were proportion of correct treatment, survival and serious adverse events.Results
Implementing aspergillus PCR tests was projected to result in residual treatment-susceptibility mismatches of <5% for a triazole resistance rate up to 20% (using voriconazole). Empiric LAmB outperformed voriconazole at resistance rates >5–20%, depending on PCR use and estimated survival benefits of voriconazole over LAmB. Combination therapy of voriconazole and LAmB performed best at all resistance rates, but the advantage over the other strategies should be weighed against the expected increased number of drug-related serious adverse events. The advantage of combination therapy over LAmB monotherapy became smaller at higher triazole resistance rates.Conclusions
Introduction of current aspergillus PCR tests on BAL fluid is an effective way to increase the proportion of patients that receive targeted therapy for IA. The results indicate that close monitoring of background resistance rates and adverse drug events are important to attain the potential benefits of LAmB. The choice of strategy ultimately depends on the probability of triazole resistance, the availability of PCR and individual patient characteristics. 相似文献64.
65.
66.
Vitamin D can be synthesized in the skin via sunlight exposure as well as ingested through diet. Vitamin D deficiency is currently a major global public health issue, with increasing prevalence in both low and high latitude locations. This cross-sectional analysis aimed to compare the intensity of individual Ultraviolet B radiation levels between women of the same ethnicity living in England and Brazil, respectively; and to investigate the association with circulating 25(OH)D concentrations. We analysed data from 135 Brazilian women (England, n = 56, 51° N; Brazil, n = 79, 16° S) recruited for the D-SOL study (Interaction between Vitamin D Supplementation and Sunlight Exposure in Women Living in Opposite Latitudes). Serum 25(OH)D concentrations were analysed by high performance liquid chromatography tandem mass spectrometry (HPLC-MS), individual UVB radiation via UVB dosimeter badges and dietary intake via 4-day diet diaries. Anthropometric, skin phototype, sociodemographic and lifestyle patterns were also assessed. Mean serum 25(OH)D concentration of England residents was significantly lower than Brazil residents. Daily individual UVB radiation level showed a strong significant positive correlation with serum 25(OH)D concentrations. The required UVB radiation to achieve 75 nmol/L was 2.2 SED and 38.8% of the total variance in 25(OH)D concentrations was explained uniquely by daily individual UVB radiation, after controlling for the influence of age and body mass index. Thus, these results highlight the strong positive association between serum 25(OH)D concentrations and individual UVB radiation and the influence of different individual characteristics and behaviours. Collectively, these factors contribute to meaningful, country-specific, public health strategies and policies for the efficient prevention and treatment of vitamin D inadequacy. 相似文献
67.
Morteza Khodaee Kayleigh Kirk Lauren A Pierpoint Sameer Dixit 《Research in sports medicine (Print)》2020,28(3):426-436
ABSTRACT Lacrosse has gained substantial popularity across age groups in the past few decades, but epidemiologic sex differences of lacrosse injuries in emergency settings have not been well described. We characterized and described lacrosse-related injuries presenting to United States Emergency Departments (US EDs) using data from the National Electronic Injury Surveillance System (NEISS). From 1997 to 2015, 7,587 lacrosse-related injuries were treated at US EDs (national estimate of 256,358 injuries). Males accounted for 75.5% of injuries. Average age was 16.0 ± 5.0 (range 5–71) years. Sprains/strains (25.4%), contusions/abrasions (23.9%), and fractures (18.7%) were the most common diagnoses. Females sustained a higher proportion of sprains/strains (36.0%) than males (21.9%) (p< 0.01), while males sustained a higher proportion of fractures (injury proportion ratios [IPR]; 21.3% vs. 10.8%, p< 0.01). Similar proportions of concussions were observed (IPR; 6.1% in males, 6.2% among females). Differences in injury patterns may be secondary to differences in rules and equipment between the two sports. 相似文献
68.
Matti A. Vuori Kennet Harald Antti Jula Liisa Valsta Tiina Laatikainen Veikko Salomaa 《Annals of medicine》2020,52(8):488-496
Abstract
Aims
The objective was to evaluate whether sodium intake, assessed with the gold standard 24-h urinary collections, was related to long-term incidence of death, cardiovascular disease (CVD) and diabetes mellitus (DM). 相似文献69.
70.
Derrick Smit Melanie De Graaf David Meyer Jolanda D.F. de Groot-Mijnes 《Ocular immunology and inflammation》2020,28(7):1049-1055
ABSTRACT Purpose: To evaluate immunoblot (IB) and polymerase chain reaction (PCR) to diagnose ocular- and neurosyphilis. Methods: Prospective cross-sectional study. Aqueous humor (AH) and cerebrospinal fluid (CSF) samples were tested for treponemal DNA or antibodies to treponemal antigens. Results: Thirteen of 106 cases had positive syphilis serology of which 69.2% were HIV+ (median CD4+ = 181 cells/µL). Four cases met CDC criteria for neurosyphilis (3 confirmed, 1 probable) and 2 additional cases required neurosyphilis treatment according to UpToDate algorithms. All AH and CSF samples tested PCR negative. Five cases were CSF IB+ and 3 cases AH IB+. Using our classification, eight patients had confirmed neurosyphilis, one had probable neurosyphilis, three had confirmed ocular syphilis and nine had probable ocular syphilis. Conclusion: Our findings suggest that IB of AH and CSF provides additional evidence to diagnose ocular and neurosyphilis and allows us to classify them as probable or confirmed. 相似文献