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   9139篇
  免费   851篇
  国内免费   51篇
耳鼻咽喉   15篇
儿科学   1415篇
妇产科学   2483篇
基础医学   751篇
口腔科学   128篇
临床医学   674篇
内科学   414篇
皮肤病学   28篇
神经病学   289篇
特种医学   51篇
外科学   325篇
综合类   789篇
一般理论   3篇
预防医学   2030篇
眼科学   58篇
药学   397篇
  4篇
中国医学   49篇
肿瘤学   138篇
  2023年   191篇
  2022年   206篇
  2021年   375篇
  2020年   385篇
  2019年   431篇
  2018年   409篇
  2017年   480篇
  2016年   443篇
  2015年   399篇
  2014年   640篇
  2013年   814篇
  2012年   487篇
  2011年   593篇
  2010年   511篇
  2009年   500篇
  2008年   449篇
  2007年   437篇
  2006年   375篇
  2005年   314篇
  2004年   276篇
  2003年   224篇
  2002年   156篇
  2001年   110篇
  2000年   103篇
  1999年   80篇
  1998年   45篇
  1997年   43篇
  1996年   40篇
  1995年   50篇
  1994年   41篇
  1993年   50篇
  1992年   30篇
  1991年   35篇
  1990年   29篇
  1989年   24篇
  1988年   30篇
  1987年   21篇
  1986年   24篇
  1985年   26篇
  1984年   30篇
  1983年   16篇
  1982年   21篇
  1981年   17篇
  1980年   18篇
  1979年   9篇
  1978年   9篇
  1977年   12篇
  1976年   9篇
  1975年   7篇
  1973年   5篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
轮状病毒是全球范围内引起婴幼儿腹泻的主要病原体,接种轮状病毒疫苗为目前最经济、有效的预防手段,很大程度上缓解了轮状病毒导致的疾病负担,但目前上市疫苗均为减毒活疫苗,存在毒力回复以及肠道不良反应等风险。因此,优化的传统活疫苗、灭活疫苗以及病毒样颗粒等亚单位疫苗成为潜在的候选疫苗,以提高轮状病毒疫苗的安全性和有效性。此文总结了市面上主要轮状病毒疫苗的应用现状以及进入临床试验新疫苗的研究情况,为后续的疫苗开发奠定基础。  相似文献   
2.
ObjectiveTo determine the long-term cardiovascular disease risk of astronauts with spaceflight exposure compared with a well-matched cohort.MethodsNational Aeronautics and Space Administration (NASA) astronauts are selected into their profession based upon education, unique skills, and health and are exposed to cardiovascular disease risk factors during spaceflight. The Cooper Center Longitudinal Study (CCLS) is a generally healthy cohort from a preventive medicine clinic in Dallas, Texas. Using a matched cohort design, astronauts who were selected beginning April 1, 1959, (and each subsequent selection class through 2009) and exposed to spaceflight were matched to CCLS participants who met astronaut selection criteria; 1514 CCLS participants matched to 303 astronauts in a 5-to-1 ratio on sex, date of birth, and age. The outcome of cardiovascular mortality through December 31, 2016, was determined by death certificate or National Death Index.ResultsThere were 11 deaths caused by cardiovascular disease (CVD) among astronauts and 46 among CCLS participants. There was no evidence of increased mortality risk in astronauts (hazard ratio [HR]=1.10; 95% confidence interval [CI], 0.50 to 2.45) with adjustment for baseline cardiovascular covariates. However, the secondary outcome of CVD events showed an increased adjusted risk in astronauts (HR=2.41; 95% CI, 1.26 to 4.63).ConclusionNo increased risk of CVD mortality was observed in astronauts with spaceflight exposure compared with a well-matched cohort, but there was evidence of increased total CVD events. Given that the duration of spaceflight will increase, particularly on missions to Mars, continued surveillance and mitigation of CVD risk is needed to ensure the safety of those who venture into space.  相似文献   
3.
目的探索输血医学在线继续教育新模式,发挥继续教育对于学科可持续发展的促进作用。方法利用在线网络平台创建中国输血大讲堂,以在线直播专题讲座的方式将输血医学相关的基础与临床研究新进展传递给全国的一线工作人员。通过问卷星软件系统进行匿名网络问卷调查,了解大讲堂观众人群构成以及对课程设置和讲课效果的评价情况。结果过去四年多已完成166期、249个学时的网络授课,超过6.3万人次收看了直播讲座。问卷调查共回收有效问卷1266份,讲座内容安排满意度评分(S1)≥90、80≤S1<90和70≤S1<80分别占61.45%、30.88%和5.85%;整体师资能力水平满意度(S2)≥90、80≤S2<90和70≤S2<80分别占68.01%、25.91%和5.06%;讲课效果包括提高临床实际处理问题的能力(89.02%)、增强基础理论水平(84.36%)、完善对输血医学学科整体认识(83.89%)、开拓学科视野(81.04%)、有助于改善与临床之间的协作关系(64.14%)和锻炼临床思维(63.35%)。结论中国输血大讲堂这种网络在线继续教育模式,可以有效地克服时间、空间的限制,为广大输血从业人员提供便捷、系统的知识更新渠道,受众人群在基础知识、基本理论、基本技能等方面得到不同程度的提高。  相似文献   
4.
《Vaccine》2022,40(6):904-911
BackgroundGSK initiated a Pregnancy Registry in the United States (US) for the reduced-antigen-content tetanus-diphtheria-acellular pertussis (Tdap; Boostrix, GSK) vaccine with the aim to detect and describe pregnancy outcomes in women vaccinated with Boostrix 28 days before estimated conception or during pregnancy.MethodsVoluntary reports of pregnancy exposure to Boostrix received from spontaneous and post-marketing surveillance sources in the US were assessed. Reports were classified as prospective or retrospective based on the knowledge of pregnancy outcomes at the time of reporting. For completeness, reports of exposure to Boostrix or to the Tdap-inactivated poliovirus vaccine (Boostrix-IPV, GSK) reported to the global safety database from countries outside the US were also evaluated.ResultsFrom May 2005 to August 2019, 1517 (1455 prospective and 62 retrospective) pregnancy reports were received in the Boostrix US Pregnancy Registry. Of the prospective reports, 250 had known outcomes: 244 live infants with no apparent birth defects (BDs), three live infants with BDs, and three spontaneous abortions with no apparent BDs. Of the retrospective reports, 55 had known outcomes: 33 live infants with no apparent BDs, 16 live infants with BDs, one spontaneous abortion with no apparent BDs, four stillbirths with no apparent BDs, and one stillbirth with BDs. Cumulatively, 1321 pregnancy reports (1006 for Boostrix; 315 for Boostrix-IPV) were received from countries outside the US. Of these, 163 prospective reports and 551 retrospective reports had known outcomes. Results were in line with those from the Boostrix US Pregnancy Registry.ConclusionsData currently available from the Boostrix US Pregnancy Registry and from countries outside the US suggested that exposure to Boostrix or Boostrix-IPV during pregnancy does not raise safety concerns related to adverse pregnancy outcomes or BDs.  相似文献   
5.
新生儿重症监护病房中早产儿的侵袭性真菌感染(invasive fungal infection,IFI)发生率较高,且早期临床诊断困难,一旦发生,病情重,疗程长,花费高,病死率较高,预后差。因此预防IFI尤为重要。目前临床常选氟康唑作为预防早产儿IFI的一线药物,但具体剂量、疗程尚不统一,使用对象及预防效果也存在争议。该文对近年来新生儿重症监护病房中药物预防早产儿IFI的研究进展进行综述,供临床医生参考。  相似文献   
6.
ObjectiveTo compare levels of postoperative oxycodone use and incisional pain between two randomized groups—an intervention and a control.DesignMixed-methods design; quantitative data achieved via a randomized controlled trial, with qualitative data collected on binder use. The primary variable was oxycodone (in milligrams) required during the first 48 hours after birth, and the secondary variable was incisional pain levels measured on Postoperative Days 1 and 2.SettingAcute-care community hospital in Wheat Ridge, Colorado, and an acute care urban hospital in Denver, Colorado.ParticipantsA total of 220 individuals in the postpartum period after having cesarean birth.Interventions/MeasurementsParticipants were randomized to the intervention group (binder) or the control group (no binder). Data were collected on opioid usage for the first 48 hours. Participants in both groups were asked to rate their incisional pain on Postoperative Day 1 (24 hours after birth) and Postoperative Day 2 (48 hours after birth). Participants in the binder group were also asked to provide feedback on their experience wearing the binder.ResultsA total of 196 participants completed the study. The overall amount of oxycodone taken by individuals in the binder group was lower than that in the control group, but the difference was not statistically significant (p = .10). Pain scores in the binder group were significantly lower on Day 2 compared with the control group (p = .002). The majority of individuals in the binder group provided positive feedback about their experience wearing the binder.ConclusionIndividuals routinely receive medications to assist with pain management postoperatively. Because of growing concerns related to the nation’s opioid addiction crisis, there is interest in using multimodal treatments to achieve adequate pain control for individuals postoperatively. Abdominal binders are a low-cost intervention to assist with pain management and, given the results of this study, seem like a reasonable option to consider.  相似文献   
7.
目的 探讨超声E-cervix技术评估宫颈机能对早产预测效能分析。方法 选取2020年1月~2021年1月200例在我院建档规律接受产检孕妇及100例孕前常规检查者,采用超声E-cervix技术评估宫颈机能,根据早产情况分为早产组和足月产组,比较两组一般资料、宫颈长度(CL)、弹性对比指数(ECI)、宫颈外口应变率(EOS)、宫颈内口应变率(IOS)、宫颈内外口应变比值(IOS/EOS)、硬度比值(HR),采用多因素Logistic回归方程分析早产的相关影响因素,采用受试者工作特征曲线(ROC)分析超声E-cervix技术参数预测早产的价值。结果 早产组宫颈手术史高于足月产组(P<0.05);妊娠期者CL、IOS、IOS/EOS高于增生期、分泌期者,HR低于增生期、分泌期者(P<0.05);早产组CL、HR低于足月产组,ECI、IOS、IOS/EOS高于足月产组(P<0.05);宫颈手术史、ECI、IOS、IOS/EOS是早产的相关危险因素,CL、HR是早产的相关保护因素(P<0.05);CL、ECI、IOS、IOS/EOS、HR预测早产的ROC曲线下面积依次为0.802、0.745、0.795、0.795、0.803,各参数联合的ROC曲线下面积为0.803。结论 ECI、IOS、IOS/EOS是早产的相关危险因素,CL、HR是早产的相关保护因素,超声E-cervix技术可检测以上参数评估宫颈机能,从而对早产做出准确预测。  相似文献   
8.
 目的 研究上海市5岁儿童出生体重、现身体质量指数(body mass index,BMI)与龋病的关系。方法 于2017年在上海市随机抽取4925名5岁儿童,开展口腔检查,并记录患龋情况。通过对家长的问卷调查获取儿童的出生体重、现BMI信息。排除1204名数据缺失儿童,共3721名儿童纳入本研究。根据出生体重将所有儿童分为低出生体重组(< 2500 g)、正常出生体重组(2500 ~ < 4000 g)和高出生体重组(≥ 4000 g),再根据现BMI将各组儿童分为消瘦的低BMI亚组(BMI < P5)、正常BMI亚组(P5 ≤ BMI ≤ P85)和超重/肥胖的高BMI亚组(BMI > P85),分析出生体重、现BMI与龋病的相关性。结果 完成检查的3721名儿童,其患龋率为53.86%,龋失补牙数(dmft)为2.38 ± 3.33。低出生体重组、正常出生体重组和高出生体重组的患龋率分别为49.65%、53.55%和59.93%,dmft分别为2.14 ± 3.13、2.37 ± 3.33、2.62 ± 3.36。高出生体重组的患龋率显著高于正常出生体重组及低出生体重组,差异均有统计学意义(χ2值分别为5.05、4.58,均P < 0.05)。高出生体重组正常BMI亚组的患龋率(61.21%)显著高于正常出生体重组的正常BMI亚组(53.61%)和高BMI亚组(51.52%),也高于低出生体重组正常BMI亚组(49.56%),差异均有统计学意义(χ2值分别为4.61、5.65、4.10,均P < 0.05)。结论 高出生体重(≥ 4000 g)的上海市5岁儿童患龋率较高。高出生体重、现BMI正常的上海市5岁儿童患龋率仍要高于出生体重正常(2500 ~ < 4000 g)而现BMI高的儿童。高出生体重可能是儿童龋病的危险因素。  相似文献   
9.
BackgroundProgress in neonatal medicine has dramatically improved the survival rate of preterm births, but the evidence suggests that these low-birth weight infants (LBWIs) go on to develop pervasive development disorders and attention deficit hyperactivity disorder (ADHD) at greater rates than the general population. Children with neurodevelopmental disorders are known to suffer from deficits in visual cognition, such as in face perception and attentional functions, the characteristics of which already manifest in early infancy.PurposeThis study aimed to investigate visual cognition in LBWIs during infancy.Subjects20 LBWIs and 20 normal-birth-weight infants (NBWIs: control) of age 9–10 months (corrected age was used for LBWIs).MethodChildren were held seated in front of an eye tracking system by a parent, and presented with facial photos as visual stimuli. During the familiarization phase, the child was presented with two images of the same human face (familiarization stimulus) on the left and right side of a display screen (5 × 10 s trials). Next, during the test phase, the child was presented with the same image on one side of the screen, and a photo of a different person’s face (novel stimulus) on the other (2 × 5 s trials). Gaze behavior was assessed in terms of the total time spent looking at either facial stimulus, and specifically at the eyes of the stimuli, as well as the number of attentional shifts between stimuli, and novelty preference.Results/DiscussionLBWIs spent significant less time looking at facial stimuli overall, and less time at the eye region, than NBWIs. These findings seem to evidence developmental differences in functions related to visual cognition.  相似文献   
10.
Maintenance and progression of pregnancy is an intricate process governed by a variety of developmental cues. Recurrent pregnancy loss (RPL) is a complication experienced by expecting mothers that is defined as three or more consecutive pregnancy losses. This review focuses on the dysfunctions of the immune system as one of the key contributors towards RPL. The current data suggests that the alloimmune and autoimmune factors contribute to the loss of fetus. Such causes despite being recognized as a definitive reason for recurrent pregnancy loss, are still under extensive investigation with new parameters being discovered and scrutinized for their association with RPLs. More in-depth and high throughput studies are required for devising better diagnostic tools and management strategies for the affected female so that they can carry their pregnancy to term.  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