全文获取类型
收费全文 | 8439篇 |
免费 | 638篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 393篇 |
妇产科学 | 227篇 |
基础医学 | 1052篇 |
口腔科学 | 219篇 |
临床医学 | 1121篇 |
内科学 | 1473篇 |
皮肤病学 | 102篇 |
神经病学 | 740篇 |
特种医学 | 175篇 |
外国民族医学 | 3篇 |
外科学 | 851篇 |
综合类 | 111篇 |
一般理论 | 13篇 |
预防医学 | 1263篇 |
眼科学 | 127篇 |
药学 | 558篇 |
中国医学 | 16篇 |
肿瘤学 | 572篇 |
出版年
2023年 | 72篇 |
2022年 | 129篇 |
2021年 | 287篇 |
2020年 | 160篇 |
2019年 | 271篇 |
2018年 | 253篇 |
2017年 | 201篇 |
2016年 | 190篇 |
2015年 | 203篇 |
2014年 | 316篇 |
2013年 | 434篇 |
2012年 | 628篇 |
2011年 | 632篇 |
2010年 | 273篇 |
2009年 | 283篇 |
2008年 | 457篇 |
2007年 | 497篇 |
2006年 | 489篇 |
2005年 | 470篇 |
2004年 | 398篇 |
2003年 | 352篇 |
2002年 | 281篇 |
2001年 | 127篇 |
2000年 | 136篇 |
1999年 | 108篇 |
1998年 | 62篇 |
1997年 | 44篇 |
1996年 | 28篇 |
1995年 | 41篇 |
1994年 | 30篇 |
1992年 | 76篇 |
1991年 | 68篇 |
1990年 | 63篇 |
1989年 | 79篇 |
1988年 | 56篇 |
1987年 | 64篇 |
1986年 | 62篇 |
1985年 | 49篇 |
1984年 | 41篇 |
1983年 | 34篇 |
1980年 | 26篇 |
1979年 | 46篇 |
1978年 | 36篇 |
1977年 | 45篇 |
1976年 | 29篇 |
1975年 | 32篇 |
1974年 | 31篇 |
1973年 | 31篇 |
1972年 | 44篇 |
1970年 | 40篇 |
排序方式: 共有9093条查询结果,搜索用时 15 毫秒
51.
52.
This study uses two types of independent variables, age and the location of the physical wound, to develop a model of injury patterning that identifies violent behavior without direct observation of the assault. In this research, domestic violence injuries are compared to accidental injuries. The results indicate that there are specific and predictable injury patterns that separate abuse from other kinds of wounds. A logistic regression model was developed to identify the regions of the body most susceptible to injury from domestic assault. Using the age of the victim and the injury regions, probabilities were calculated to determine which wounds were caused by abuse. 相似文献
53.
Sachintha Perera Sudhir Rathore Joanne Shannon Peter Clarkson Matthew Faircloth Vinod Achan 《The British Journal of Cardiology》2022,29(1)
Presentation and outcomes of patients with ST-elevation myocardial infarction (STEMI) may change during viral pandemics. We compared symptom-tocall (STC), call-to-balloon (CTB), doorto-balloon (DTB) times; high-sensitivity troponin (hs-cTnI) levels; and survival of patients (n=39) during the first wave of the COVID-19 pandemic (defined as a ‘COVID period’ starting four weeks before lockdown) to historical controls from a ‘pre-COVID period’ (n=45).STEMI admissions fell one week before lockdown by 29%. Median STC times began to rise one month before lockdown (54 vs. 25 min, p=0.06), with peak increases between 9 March and 5 April (166 vs. 59 min, p=0.04). Median CTB and DTB times were unchanged. Mean peak hs-cTnI increased during COVID-19 (15,225 vs. 8,852 ng/ml, p=0.004). Six-month survival following all STEMI reduced (82.1% vs. 95.6%, p<0.05).STC times are the earliest indicator that STEMI-patient behaviour changed four weeks before lockdown, correlating with higher troponin levels and reduced survival. These early signals could guide public health interventions during future pandemics.Key words: COVID-19, outcomes, percutaneous coronary intervention (PCI), ST-elevation myocardial infarction (STEMI) 相似文献
54.
Hanzhi Yu Runming Du Minmin Wang Fengyun Yu Juntao Yang Lirui Jiao Zhuoran Wang Haitao Liu Peixin Wu Till Brnighausen Lan Xue Chen Wang Shannon McMahon Pascal Geldsetzer Simiao Chen 《JMIR Public Health and Surveillance》2022,8(6)
BackgroundCOVID-19 vaccines are in short supply worldwide. China was among the first countries to pledge supplies of the COVID-19 vaccine as a global public product, and to date, the country has provided more than 600 million vaccines to more than 200 countries and regions with low COVID-19 vaccination rates. Understanding the public’s attitude in China toward the global distribution of COVID-19 vaccines could inform global and national decisions, policies, and debates.ObjectiveThe aim of this study was to determine the attitudes of adults living in China regarding the global allocation of COVID-19 vaccines developed in China and how these attitudes vary across provinces and by sociodemographic characteristics.MethodsWe conducted a cross-sectional online survey among adults registered with the survey company KuRunData. The survey asked participants 31 questions about their attitudes regarding the global allocation of COVID-19 vaccines developed in China. We disaggregated responses by province and sociodemographic characteristics. All analyses used survey sampling weights.ResultsA total of 10,000 participants completed the questionnaire. Participants generally favored providing COVID-19 vaccines to foreign countries before fulfilling domestic needs (75.6%, 95% CI 74.6%-76.5%). Women (3778/4921, 76.8%; odds ratio 1.18, 95% CI 1.07-1.32; P=.002) and those living in rural areas (3123/4065, 76.8%; odds ratio 1.13, 95% CI 1.01-1.27; P=.03) were especially likely to hold this opinion. Most respondents preferred providing financial support through international platforms rather than directly offering support to individual countries (72.1%, 95% CI 71%-73.1%), while for vaccine products they preferred direct provision to relevant countries instead of via a delivery platform such as COVAX (77.3%, 95% CI 76.3%-78.2%).ConclusionsAmong our survey sample, we found that adults are generally supportive of the international distribution of COVID-19 vaccines, which may encourage policy makers to support and implement the distribution of COVID-19 vaccines developed in China worldwide. Conducting similar surveys in other countries could help align policy makers’ actions on COVID-19 vaccine distribution with the preferences of their constituencies. 相似文献
55.
Kerry L. Shannon Valerie O. Osula Kathryn ShawSaliba Justin Hardick Breana McBryde Andrea Dugas YuHsiang Hsieh Bhakti Hansoti Richard E. Rothman Emergency Department National Influenza Network Investigators 《Influenza and other respiratory viruses》2022,16(4):780
BackgroundInfluenza causes significant morbidity and mortality in the United States. Among patients infected with influenza, the presence of bacterial co‐infection is associated with worse clinical outcomes; less is known regarding the clinical importance of viral co‐infections. The objective of this study was to determine rates of viral co‐infections in emergency department (ED) patients with confirmed influenza and association of co‐infection with disease severity.MethodsSecondary analysis of a biorepository and clinical database from a parent study where rapid influenza testing was implemented in four U.S. academic EDs, during the 2014–2015 influenza season. Patients were systematically tested for influenza virus using a validated clinical decision guideline. Demographic and clinical data were extracted from medical records; nasopharyngeal specimens from influenza‐positive patients were tested for viral co‐infections (ePlex, Genmark Diagnostics). Patterns of viral co‐infections were evaluated using chi‐square analysis. The association of viral co‐infection with hospital admission was assessed using univariate and multivariate regression.ResultsThe overall influenza A/B positivity rate was 18.1% (1071/5919). Of the 999 samples with ePlex results, the prevalence of viral co‐infections was 7.9% (79/999). The most common viral co‐infection was rhinovirus/enterovirus (RhV/EV), at 3.9% (39/999). The odds of hospital admission (OR 2.33, 95% CI: 1.01–5.34) increased significantly for those with viral co‐infections (other than RhV/EV) versus those with influenza A infection only.ConclusionPresence of viral co‐infection (other than RhV/EV) in ED influenza A/B positive patients was independently associated with increased risk of hospital admission. Further research is needed to determine clinical utility of ED multiplex testing. 相似文献
56.
Miruthula Tamil Selvan Sachithra Gunasekara Ping Xiao Kristen Griffin Shannon R. Cowan Sai Narayanan Akhilesh Ramachandran Darren E. Hagen Jerry W. Ritchey Jennifer M. Rudd Craig A. Miller 《Viruses》2022,14(6)
Continued emergence of SARS-CoV-2 variants highlights the critical need for adaptable and translational animal models for acute COVID-19. Limitations to current animal models for SARS CoV-2 (e.g., transgenic mice, non-human primates, ferrets) include subclinical to mild lower respiratory disease, divergence from clinical COVID-19 disease course, and/or the need for host genetic modifications to permit infection. We therefore established a feline model to study COVID-19 disease progression and utilized this model to evaluate infection kinetics and immunopathology of the rapidly circulating Delta variant (B.1.617.2) of SARS-CoV-2. In this study, specific-pathogen-free domestic cats (n = 24) were inoculated intranasally and/or intratracheally with SARS CoV-2 (B.1.617.2). Infected cats developed severe clinical respiratory disease and pulmonary lesions at 4- and 12-days post-infection (dpi), even at 1/10 the dose of previously studied wild-type SARS-CoV-2. Infectious virus was isolated from nasal secretions of delta-variant infected cats in high amounts at multiple timepoints, and viral antigen was co-localized in ACE2-expressing cells of the lungs (pneumocytes, vascular endothelium, peribronchial glandular epithelium) and strongly associated with severe pulmonary inflammation and vasculitis that were more pronounced than in wild-type SARS-CoV-2 infection. RNA sequencing of infected feline lung tissues identified upregulation of multiple gene pathways associated with cytokine receptor interactions, chemokine signaling, and viral protein–cytokine interactions during acute infection with SARS-CoV-2. Weighted correlation network analysis (WGCNA) of differentially expressed genes identified several distinct clusters of dysregulated hub genes that are significantly correlated with both clinical signs and lesions during acute infection. Collectively, the results of these studies help to delineate the role of domestic cats in disease transmission and response to variant emergence, establish a flexible translational model to develop strategies to prevent the spread of SARS-CoV-2, and identify potential targets for downstream therapeutic development. 相似文献
57.
Three related amides (diuron, 2-(octyloxy) acetanilide, and salicylanilide) were evaluated for toxicity to aquatic microcosm communities. Effects were measured at the ecosystem level using changes in pH, Eh (redox potential), and dissolved oxygen as indicators of toxicity. These values were used to calculate the resistance, resilience, and relative instability of the microecosystems to each compound at comparable dose levels of approximately 2500 micrograms/liter. Such measures have often been used in a theoretical context, but have not received wide practical application. The systems showed low resistance and no resilience to diuron, high resistance and low resilience to 2-(octyloxy) acetanilide, and no response to salicylanilide. At a higher exposure level (9800 micrograms/liter salicylanilide), the systems showed low resistance and high resilience. Both this approach and more traditional dose-response measures of toxicity indicated that diuron was clearly the most toxic compound, followed by 2-(octyloxy) acetanilide and salicylanilide. While microcosm toxicity tests were slightly less sensitive than some single species tests, they provided important additional information on the extent of perturbations and the rate of ecosystem recovery. 相似文献
58.
59.
Anna V. Tinker Alon D. Altman Marcus Q. Bernardini Prafull Ghatage Lilian T. Gien Diane Provencher Shannon Salvador Sarah Doucette Amit M. Oza 《Current oncology (Toronto, Ont.)》2022,29(6):4354
The majority of patients with advanced, high-grade epithelial-tubo ovarian cancer (EOC) respond well to initial treatment with platinum-based chemotherapy; however, up to 80% of patients will experience a recurrence. Poly(ADP-ribose) Polymerase (PARP) inhibitors have been established as a standard of care maintenance therapy to prolong remission and prevent relapse following a response to first-line platinum-chemotherapy. Olaparib and niraparib are the PARP inhibitors currently approved for use in the first-line maintenance setting in Canada. Selection of maintenance therapy requires consideration of patient and tumour factors, presence of germline and somatic mutations, expected drug toxicity profile, and treatment access. This paper discusses the current clinical evidence for first-line PARP inhibitor maintenance therapy in patients with advanced, high-grade EOC and presents consensus statements and a treatment algorithm to aid Canadian oncologists on the selection and use of PARP inhibitors within the Canadian EOC treatment landscape. 相似文献
60.
Amanda Reiff Metz Matthew Bauer Chelsey Epperly Ginger Stringer Kristen E. Marshall Lindsey Martin Webb Molly Hetherington-Rauth Shannon R. Matzinger Sarah Elizabeth Totten Emily A. Travanty Kristen M. Good Alexis Burakoff 《Emerging infectious diseases》2022,28(8):1551
A COVID-19 outbreak occurred among Cameron Peak Fire responders in Colorado, USA, during August 2020–January 2021. The Cameron Peak Fire was the largest recorded wildfire in Colorado history, lasting August–December 2020. At least 6,123 responders were involved, including 1,260 firefighters in 63 crews who mobilized to the fire camps. A total of 79 COVID-19 cases were identified among responders, and 273 close contacts were quarantined. State and local public health investigated the outbreak and coordinated with wildfire management teams to prevent disease spread. We performed whole-genome sequencing and applied social network analysis to visualize clusters and transmission dynamics. Phylogenetic analysis identified 8 lineages among sequenced specimens, implying multiple introductions. Social network analysis identified spread between and within crews. Strategies such as implementing symptom screening and testing of arriving responders, educating responders about overlapping symptoms of smoke inhalation and COVID-19, improving physical distancing of crews, and encouraging vaccinations are recommended. 相似文献