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   4086篇
  免费   174篇
  国内免费   25篇
耳鼻咽喉   23篇
儿科学   446篇
妇产科学   209篇
基础医学   259篇
口腔科学   69篇
临床医学   305篇
内科学   460篇
皮肤病学   21篇
神经病学   693篇
特种医学   76篇
外科学   164篇
综合类   108篇
预防医学   995篇
眼科学   4篇
药学   403篇
中国医学   8篇
肿瘤学   42篇
  2023年   97篇
  2022年   128篇
  2021年   204篇
  2020年   166篇
  2019年   200篇
  2018年   186篇
  2017年   186篇
  2016年   194篇
  2015年   130篇
  2014年   344篇
  2013年   408篇
  2012年   179篇
  2011年   281篇
  2010年   172篇
  2009年   240篇
  2008年   222篇
  2007年   215篇
  2006年   146篇
  2005年   105篇
  2004年   81篇
  2003年   66篇
  2002年   58篇
  2001年   48篇
  2000年   35篇
  1999年   29篇
  1998年   17篇
  1997年   27篇
  1996年   28篇
  1995年   18篇
  1994年   10篇
  1993年   17篇
  1992年   11篇
  1991年   10篇
  1990年   4篇
  1989年   1篇
  1988年   4篇
  1987年   4篇
  1986年   4篇
  1985年   5篇
  1977年   2篇
  1975年   1篇
  1973年   1篇
  1968年   1篇
排序方式: 共有4285条查询结果,搜索用时 15 毫秒
1.
2.
《Vaccine》2022,40(5):706-713
BackgroundThe COVID-19 pandemic has disrupted healthcare, including immunization practice and well child visit attendance. Maintaining vaccination coverage is important to prevent disease outbreaks and morbidity. We assessed the impact of the COVID-19 pandemic on pediatric and adolescent vaccination administration and well child visit attendance in the United States.MethodsThis cross-sectional study used IBM MarketScan Commercial Database (IMC) with Early View (healthcare claims database) and TriNetX Dataworks Global Network (electronic medical records database) from January 2018–March 2021. Individuals ≤ 18 years of age who were enrolled during the analysis month of interest (IMC with Early View) or had ≥ 1 health encounter at a participating institution (TriNetX Dataworks) were included. We calculated the monthly percent difference between well child visit attendance and vaccine administration rates for 10 recommended pediatric/adolescent vaccines in 2020 and 2021 compared with 2018–2019. Data were stratified by the age groups 0–2 years, 4–6 years, and 9–16 years.ResultsIn IMC with Early View, the average monthly enrollment for children 0–18 years of age was 5.2 million. In TriNetX Dataworks, 12.2 million eligible individuals were included. Well child visits and vaccinations reached the lowest point in April 2020 compared with 2018–2019. Well child visit attendance and vaccine administration rates were inversely related to age, with initial reductions highest for adolescents and lowest for ages 0–2 years. Rates rebounded in June and September 2020 and stabilized to pre-pandemic levels in Fall 2020. Rates dropped below baseline in early 2021 for groups 0–2 years and 4–6 years.ConclusionsWe found substantial disruptions in well child visit attendance and vaccination administration for children and adolescents during the COVID-19 pandemic in 2020 and early 2021. Continued efforts are needed to monitor recovery and catch up to avoid outbreaks and morbidity associated with vaccine-preventable diseases.  相似文献   
3.
目的调查少数民族地区青少年对新冠疫情的认知及应对情况。方法采用分层抽样的方法,通过“问卷星”在线平台对香格里拉市1949名在校学生进行调查。结果结果显示,81.94%的学生在2020年1月初之前已知晓疫情;83.12%的学生通过电视和微信知晓疫情;9333%的学生认为病毒通过飞沫传播;94.80%的学生会通过戴口罩、不聚餐等方式进行防护;疫情相关知识的正确率为71.44%。不同年龄、性别、民族、专业、生源地、家庭年收入的学生对部分调查问题的差异有统计学意义(P<0.05)。结论学生对疫情认知整体情况较好,部分问题仍有较大提升空间。学校应做好疫情常态化防控,完善心理疏导体系,多措并举,引导学生做好自我防护。  相似文献   
4.
Background and aimsCurrent strategies to reduce cardiovascular disease (CVD) risk in young adults are largely limited to those at extremes of risk. In cohort studies we have shown cluster analysis identified a large sub-group of adolescents with multiple risk factors. This study examined if individuals classified at ‘high-risk’ by cluster analysis could also be identified by their Framingham risk scores.Methods and resultsRaine Study data at 17- (n = 1048) and 20-years (n = 1120) identified high- and low-risk groups by cluster analysis using continuous measures of systolic BP, BMI, triglycerides and insulin resistance. We assessed:- CVD risk at 20-years using the Framingham 30 yr-risk-score in the high- and low-risk clusters, and cluster stability from adolescence to adulthood.Cluster analysis at 17- and 20-years identified a high-risk group comprising, 17.9% and 21.3%, respectively of the cohort. In contrast, only 1.2% and 3.4%, respectively, met the metabolic syndrome criteria, all of whom were within the high-risk cluster. Compared with the low-risk cluster, Framingham scores of the high-risk cluster were elevated in males (9.4%; 99%CI 8.3, 10.6 vs 6.0%; 99%CI 5.7, 6.2) and females (4.9%; 99%CI 4.4, 5.4 vs 3.2%; 99%CI 3.0, 3.3) (both P < 0.0001). A score >8 for males and >4 for females identified those at high CVD risk with 99% confidence.ConclusionCluster analysis using multiple risk factors identified ~20% of young adults at high CVD risk. Application of our Framingham 30 yr-risk cut-offs to individuals allows identification of more young people with multiple risk factors for CVD than conventional metabolic syndrome criteria.  相似文献   
5.
《Pancreatology》2022,22(8):1175-1180
BackgroundHepatic steatosis has been described as a common finding in adults following total pancreatectomy with islet autotransplantation (TPIAT) but it is unknown if this occurs in children and adolescents.ObjectivesTo define the frequency of post-TPIAT hepatic steatosis in a sample of children and adolescents and to identify clinical predictors of incident steatosis post-TPIAT.MethodsIn this prospective study, consecutive participants at least 1-month post-TPIAT underwent a liver MRI with proton density fat fraction (PDFF) and blood draw at our pediatric academic medical center between April 2021 and January 2022. Comparison clinical pre-TPIAT liver MRI or ultrasound and insulin use and graft function data were extracted from the medical record. T-tests were used for the comparison of means across continuous variables between participants with and without post-TPIAT steatosis.ResultsA total of 20 participants (mean: 13 ± 4 years; 12 female) were evaluated. Mean liver PDFF at research MRI was 7.4 ± 6.2% (range: 2–25%). Seven participants (35%) had categorical hepatic steatosis (PDFF>5%) post-TPIAT, five of whom had pre-TPIAT steatosis, reflecting a 13% (2/15; 95% CI: 2–40%) incidence of post-TPIAT steatosis. Participant characteristics were not significantly different between subgroups with and without post-TPIAT steatosis. Mean PDFF at research MRI was not different between graft function subgroups (7.5% optimal/good vs. 7.3% marginal/failure; p = .96).ConclusionOur study shows a moderate prevalence but low incidence of hepatic steatosis in a small sample of children and adolescents post-TPIAT. This study raises questions about a causal relationship between TPIAT and hepatic steatosis.  相似文献   
6.
目的 探索青少年网络成瘾和睡眠时长在受校园欺凌与抑郁关系之间的中介作用,为青少年抑郁的预防干预提供依据。 方法 使用青少年健康相关危险行为问卷及CES - D抑郁量表,采用多阶段整群抽样法抽取徐州市4 190名青少年进行问卷调查。结果 在控制人口学等变量后,受校园欺凌、网络成瘾、睡眠时长对抑郁均有预测作用(r = 0.283,P<0.01;r = 0.331,P<0.01;r = - 0.184,P<0.01)。路径分析表明,网络成瘾在受校园欺凌和青少年抑郁之间起中介作用;网络成瘾和睡眠时长在受校园欺凌和青少年抑郁间起链式中介作用。结论 受校园欺凌不仅直接影响青少年抑郁,还通过网络成瘾和睡眠时长的链式中介作用间接影响青少年抑郁。可通过减少青少年网络使用和提高睡眠时长来降低受校园欺凌对青少年抑郁的影响。  相似文献   
7.
8.
Background and aims(Poly)phenols might contribute to prevent cardiovascular disease, but limited prospective studies exist among adolescents. This study aimed to evaluate within-subject longitudinal changes in (poly)phenols intakes and food group contributors while also exploring the association with metabolic syndrome risk (MetS) during 10 years of follow up in European adolescents becoming young adults.Methods and resultsIn 164 participants (58% girls, 13-18 y at baseline) from Ghent, Zaragoza and Lille, longitudinal data (2006–2016) on (poly)phenol intake was retrieved via 2 or 3 24 h recalls. Linear and logistic longitudinal regression tested the association of (poly)phenols intake (total and classes) with Mets risk or its components (waist-height-ratio, HDL cholesterol, LDL cholesterol, triglycerides, blood pressure and insulin resistance index), adjusted for age, sex, country and other nutrient intakes. The total (poly)phenols intake was 421 ± 107 mg/day (192 mg/1000 kcal/day) at baseline, while 610 ± 101 mg/day (311 mg/1000 kcal/day) at follow-up. The three major food sources for (poly)phenols were ‘chocolate’, ‘fruit and vegetable juices’, ‘cakes and biscuits’ during adolescence and ‘coffee’, ‘tea’ and ‘chocolate’ during adulthood. Phenolic acid intake was associated with less LDL increase over time, while stilbene intake with a steeper increase in triglycerides over time.ConclusionsDifferences in major (poly)phenols contributors over time were partially explained by age-specific dietary changes like increased coffee and tea during adulthood. Some significant (poly)phenols-MetS associations might argue for nutrition-based disease prevention during adolescence, especially since adolescents had low (poly)phenols intake.  相似文献   
9.
Background and aimScreening for pediatric hypertension (HTN) is based on several measurements of blood pressure (BP) in different visits. We aimed to assess its feasibility in outpatient youths with overweight/obesity (OW/OB) in terms of adherence to two-repeated measurements of BP and to show the features of youths who missed the follow-up and the predictive role of clinical and/or anamnestic features on confirmed HTN.Methods and resultsSix hundred, eighty-eight youths (9–17 years) with OW/OB, consecutively recruited, underwent a first measurement of BP. Those exhibiting BP levels within the hypertensive range were invited to repeat a second measurement within 1–2 weeks. Confirmed HTN was diagnosed when BP in the hypertensive range was confirmed at the second measurement. At entry, 174 youths (25.1%) were classified as hypertensive. At the second visit, 66 youths (37.9%) were lost to follow-up. In the remaining 108 participants, HTN was confirmed in 59, so that the prevalence of confirmed HTN was 9.5% in the overall sample; it was higher in adolescents than children (15.9% vs 6.8%, P = 0.001). HTN at first visit showed the best sensitivity (100%) and a good specificity (91%) for confirmed HTN. The association of HTN at first visit plus familial HTN showed high specificity (98%) and positive predictive value of 70%.ConclusionThe high drop-out rate confirms the real difficulty to obtain a complete diagnostic follow up in the obese population. Information about family history of HTN may assist pediatricians in identifying those children who are at higher risk of confirmed HTN.  相似文献   
10.
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