首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   15698篇
  免费   803篇
  国内免费   11篇
耳鼻咽喉   27篇
儿科学   666篇
妇产科学   580篇
基础医学   976篇
口腔科学   279篇
临床医学   1706篇
内科学   2730篇
皮肤病学   111篇
神经病学   1093篇
特种医学   306篇
外科学   955篇
综合类   145篇
现状与发展   1篇
一般理论   7篇
预防医学   5214篇
眼科学   100篇
药学   836篇
  1篇
中国医学   15篇
肿瘤学   764篇
  2024年   11篇
  2023年   711篇
  2022年   1311篇
  2021年   1263篇
  2020年   1438篇
  2019年   831篇
  2018年   781篇
  2017年   938篇
  2016年   946篇
  2015年   751篇
  2014年   1232篇
  2013年   989篇
  2012年   524篇
  2011年   442篇
  2010年   729篇
  2009年   760篇
  2008年   361篇
  2007年   374篇
  2006年   286篇
  2005年   207篇
  2004年   127篇
  2003年   143篇
  2002年   157篇
  2001年   132篇
  2000年   115篇
  1999年   128篇
  1998年   128篇
  1997年   88篇
  1996年   95篇
  1995年   85篇
  1994年   69篇
  1993年   41篇
  1992年   50篇
  1991年   51篇
  1990年   41篇
  1989年   25篇
  1988年   43篇
  1987年   19篇
  1986年   6篇
  1985年   14篇
  1984年   15篇
  1982年   9篇
  1981年   5篇
  1980年   6篇
  1979年   5篇
  1978年   4篇
  1974年   4篇
  1973年   4篇
  1971年   4篇
  1965年   3篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
41.
BackgroundWomen with preeclampsia are at increased short-term risk of adverse cardiovascular outcomes during pregnancy and the early postpartum period. We aimed to develop and internally validate a risk assessment tool to predict acute cardiovascular morbidity in preeclampsia.MethodsThe study was conducted at an academic obstetrics hospital. Participants with preeclampsia at delivery from 2007 to 2017 were included. A model to predict acute cardiovascular morbidity at delivery and within 6 weeks after delivery was developed and evaluated. The primary composite outcome included pulmonary edema/acute heart failure, myocardial infarction, aneurysm, cardiac arrest/ventricular fibrillation, heart failure/arrest during surgery or procedure, cerebrovascular disorders, cardiogenic shock, conversion of cardiac rhythm, and difficult-to-control severe hypertension. We assessed model discrimination and calibration. We used bootstrapping for internal validation.ResultsA total of 4171 participants with preeclampsia were included. The final model comprised 8 variables. Predictors positively associated with acute cardiovascular morbidity (presented as odds ratio with 95% confidence interval) were: gestational age at delivery (20-36 weeks: 5.36 [3.67-7.82]; 37-38 weeks: 1.75 [1.16-2.64]), maternal age (≥ 40 years: 1.65 [1.00-2.72]; 35-39 years: 1.49 [1.07-2.09]), and previous caesarean delivery (1.47 [1.01-2.13]). The model had an area under the receiver operating characteristic curve of 0.72 (95% CI 0.69-0.74). Moreover, it was adequately calibrated and performed well on internal validation.ConclusionsThis risk prediction tool identified women with preeclampsia at highest risk of acute cardiovascular morbidity. If externally validated, this tool may facilitate early interventions aimed at preventing adverse cardiovascular outcomes in pregnancy and postpartum.  相似文献   
42.
This study evaluated the genetic variation of 17 autosomal short tandem repeat (STR) loci included in the PowerPlex® 18D Kit. Samples of 562 unrelated healthy Lahu individuals living in Yunnan Province in southwestern China were investigated. The data were analyzed to provide information on allele frequencies and other statistical parameters relevant to the forensic population. Of the 17 loci, 16 reached the Hardy–Weinberg equilibrium after Bonferroni correction. A total of 176 alleles were identified in 17 STR loci, and allele frequencies ranged from 0.000 890 to 0.578 292. The combined discrimination power (CPD) and probability of excluding paternity (CPE) of the 17 STR loci were 0.999 999 999 999 999 999 489 and 0.999 998 301 753 122. The genetic relationships among 28 populations were also estimated.  相似文献   
43.
《Academic pediatrics》2022,22(1):55-61
ObjectiveTo identify and contrast risk factors for six-month pediatric asthma readmissions using traditional models (Cox proportional-hazards and logistic regression) and artificial neural-network modeling.MethodsThis retrospective cohort study of the 2013 Nationwide Readmissions Database included children 5 to 18 years old with a primary diagnosis of asthma. The primary outcome was time to asthma readmission in the Cox model, and readmission within 180 days in logistic regression. A basic neural network construction with 2 hidden layers and multiple replications considered all dataset variables and potential variable interactions to predict 180-day readmissions. Logistic regression and neural-network models were compared on area-under-the receiver-operating curve.ResultsOf 18,489 pediatric asthma hospitalizations, 1858 were readmitted within 180 days. In Cox and logistic models, longer index length of stay, public insurance, and nonwinter index admission seasons were associated with readmission risk, whereas micropolitan county was protective. In neural-network modeling, 9 factors were significantly associated with readmissions. Four overlapped with the Cox model (nonwinter-month admission, long length of stay, public insurance, and micropolitan hospitals), whereas 5 were unique (age, hospital bed number, teaching-hospital status, weekend index admission, and complex chronic conditions). The area under the curve was 0.592 for logistic regression and 0.637 for the neural network.ConclusionsDifferent methods can produce different readmission models. Relying on traditional modeling alone overlooks key readmission risk factors and complex factor interactions identified by neural networks.  相似文献   
44.
Background: Egyptian street youth use substances including tobacco, illicit drugs, and pharmaceutical drugs. To understand the circumstances, including adverse childhood experiences, that place adolescents at risk for engaging in substance use, we conducted in-depth interviews among a sample of Egyptian street children. Methods: From youth residing at or attending Caritas, a non-profit organization, which provides shelter and education to street youth, seven girls and twelve boys, aged 12–18 years, participated in open-ended, in-depth interviews. Results: Eight out of the 19 participants reported family history (early exposure) to substance use; and seven of them were initiated by either a family member (sibling), friend or coworker. Most of the participants reported a history of conflict with or abuse (verbal or physical) by their parents or siblings, or stressful situations at home; they used substance(s) to alleviate their stress. Few attended school, and some were forced to work and help their family. Conclusions: Among Egyptian youth, adverse childhood experiences, such as poverty, child abuse, and family substance use, challenge somewhat susceptible youths and lead them to the path of substance use and addiction. Prevention intervention should be multifaceted, culturally adaptable, and primarily targeting the social environment during childhood.  相似文献   
45.
BackgroundEvidence regarding the outcomes of percutaneous coronary intervention (PCI) in low-and-middle incomes countries remains limited.ObjectivesTo report the outcomes post PCI at discharge, 30 days and 12 months in Vietnam and identify the key factors associated with adverse outcomes at 12 months.MethodsWe used data from a single centre prospective cohort in Vietnam. Data regarding demographics, clinical presentation, procedural information, and outcomes of patients were collected and analysed. Primary outcomes were mortality and major adverse cardiac and cerebrovascular events.ResultsIn total, 926 patients were included. Poor outcomes were relatively low in those undergoing PCI. Predictors of mortality and major adverse cardiac and cerebrovascular events at 12 months post-PCI included being older than 75, being male, having acute myocardial infarction, left ventricular ejection fraction ≤ 40%, prior cerebral vascular disease and having an unsuccessful PCI.ConclusionsAdverse outcomes of patients undergoing PCI in Vietnam are relatively low in comparison with those reported in other countries across the Asia Pacific region. Identification of factors associated with poor outcomes is beneficial for improving the quality of cardiac care and developing the prediction model of outcomes post-PCI in Vietnam.  相似文献   
46.
Background and aimsObesity and overweight in children are associated with an increased risk of several health issues. The present study aimed to assess the effects of a multi-disciplinary program (including nutrition education using a smartphone game, physical activity, and cognitive behavioral therapy [CBT]) on the management of obesity and overweight in elementary school girls.Methods and resultsSixty-two school girls above the 85th percentile of body mass index (BMI) for age were randomly assigned to two groups. During 10 weeks of study, the intervention group received a multi-disciplinary intervention, including nutrition education using a smartphone game, aerobic exercise, and CBT. The control group received usual traditional nutritional education. Biochemical and metabolic factors were assessed, including fasting blood sugar (FBS), lipid profile, serum leptin, and anthropometric measurements. The Dutch Eating Behavior Questionnaire (DEBQ) and metabolic equivalent test (MET) were also conducted. The intervention group showed more promising results in weight loss, waist circumference (WC), hip circumference (HC), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), and FBS compared to the control group (P < 0.05). In addition, MET and DEBQ scores in all three sections of emotions, stimuli, and restriction were better in the intervention group than in the control group (P < 0.05). However, there was no significant difference between groups regarding the results of serum leptin and waist-to-hip ratio (WHR; p > 0.05).ConclusionsThe results indicated that education through smartphone games could possibly affect performance in real life. In addition, the multi-disciplinary approach to childhood obesity might have better performance in most areas than the single-intervention approach in obesity management.  相似文献   
47.
The association between kidney function and cancer incidence is inconsistent among previous reports, and data on the Japanese population are lacking. It is unknown whether kidney function modifies the cancer risk of other factors. We aimed to evaluate the association of estimated glomerular filtration rate (eGFR) with cancer incidence and mortality in 55 242 participants (median age, 57 years; 55% women) from the Japan Multi-Institutional Collaborative Cohort Study. We also investigated differences in cancer risk factors between individuals with and without kidney dysfunction. During a median 9.3-year follow-up period, 4278 (7.7%) subjects developed cancer. Moderately low and high eGFRs were associated with higher cancer incidence; compared with eGFR of 60-74 ml/min/1.73 m2, the adjusted hazard ratios (HRs) (95% confidence intervals [CIs]) for eGFRs of ≥90, 75-89, 45-59, 30-44 and 10-29 ml/min/1.73 m2 were 1.18 (1.07-1.29), 1.09 (1.01-1.17), 0.93 (0.83-1.04), 1.36 (1.00-1.84) and 1.12 (0.55-2.26), respectively. High eGFR was associated with higher cancer mortality, while low eGFR was not; the adjusted subdistribution HRs (95% CIs) for eGFRs of ≥90 and 75-89 ml/min/1.73 m2 were 1.58 (1.29-1.94) and 1.27 (1.08-1.50), respectively. Subgroup analyses of participants with eGFRs ≥60 and <60 ml/min/1.73 m2 revealed elevated cancer risks of smoking and family history of cancer in those with eGFR <60 ml/min/1.73 m2, with significant interactions. Our findings suggest that the relationship between eGFR and cancer incidence was U-shaped. Only high eGFR was associated with cancer mortality. Kidney dysfunction enhanced cancer risk from smoking.  相似文献   
48.
ObjectiveTo examine the association between body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]) and mortality after the first year post spinal cord injury (SCI) overall and across demographic and injury characteristics.DesignCohort study.SettingSixteen Spinal Cord Injury Model Systems (SCIMS) centers.ParticipantsSCIMS Database participants age 20 years or older and having a BMI assessment during the 2007-2011 wave of data collection.InterventionsNot applicable.Main Outcome MeasuresAll-cause mortality rate. Life table method and log-rank test were used to estimate and compare mortality rates across BMI groups and other factors. Cox proportional hazard regression model was conducted to estimate hazard ratio (HR) and 95% confidence interval (CI).ResultsA total of 2346 participants (N=2346) with SCI were classified into 1 of the 8 BMI groups: <18.5 (6.9%), 18.5-19.9 (7.3%), 20.0-22.49 (15.0%), 22.5-24.9 (18.8%), 25.0-27.49 (17.5%), 27.5-29.9 (13.2%), 30.0-34.9 (13.5%), and ≥35.0 (7.8%). Compared with people with BMI of 22.5-29.9, a higher mortality risk was observed among people with BMI<18.5 (HR, 1.76; 95% CI, 1.25-2.49), 18.5-19.9 (HR, 1.51; 95% CI, 1.06-2.15), and ≥35.0 (HR, 1.51; 95% CI, 1.11-2.07) after adjusting for confounding factors (sex, age at the time of BMI assessment, marital status, neurologic status). The U-shape BMI-mortality relationship varied by age, sex, neurologic status, and years since injury.ConclusionsTo improve life expectancy after SCI, health care professionals could focus on weight management among patients with relatively low and extremely high BMI, defined by demographic and injury-related characteristics. Future studies should explore factors that contribute to such a higher mortality after SCI, including pre-existing conditions, poor diet and/or nutrition, and cardiorespiratory fitness.  相似文献   
49.
ObjectiveTo develop a trail running injury screening instrument (TRISI) for utilisation as clinical decision aid in determining if a trail runner is at an increased risk for injury.DesignMultiple methods approach.MethodsThe study utilised five phases 1) identification of injury risk factors 2) determining the relevance of each identified risk factor in a trail running context, 3) creating the content of the Likert scale points from 0 to 4, 4) rescaling the Likert scale points to determine numerical values for the content of each Likert scale point, and 5) determining a weighted score for each injury risk factor that contributes to the overall combined composite score.ResultsOf the 77 identified injury risk factors, 26 were deemed relevant in trail running. The weighted score for each injury risk factor ranged from 2.21 to 5.53 with the highest calculated score being 5.53. The final TRISI includes risk categories of training, running equipment, demographics, previous injury, behavioural, psychological, nutrition, chronic disease, physiological, and biomechanical factors.ConclusionThe developed TRISI aims to assist the clinician during pre-race injury screening or during a training season to identify meaningful areas to target in designing injury risk management strategies and/or continuous health education.  相似文献   
50.
ObjectiveVaccine hesitancy is a persistent barrier to vaccination uptake, and health professionals report interactions with such parents to be difficult. Using discourse analytic techniques, we examine the foundation of a therapeutic relationship: the display of empathy and attempts to build rapport, in consultations between immunisation specialists and vaccine reluctant parents.MethodsConsultations between consenting clinicians and parents in two Specialist Immunisation Clinics in Australia were recorded. Twelve conversations between the clinicians and parents were analysed using interactional sociolinguistic (IS) discourse analytic methods.ResultsThis paper takes a case study approach by citing two interactions that exemplify the interactional work of the consultants as they strive to engender mutual understanding and goodwill, noting examples of discursive choices that demonstrate empathy and the building of rapport.ConclusionAwareness of discourse strategies that interweave relational and clinical goals enable a more nuanced understanding of communication skills that support a guiding partnership in vaccine related decisions with parents.Practical implicationsThrough highlighting the strategic interactional work that displays empathy and builds rapport, we can inform educational approaches and build a repertoire of communication choices that strengthen the communication skills of health professionals.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号