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   27715篇
  免费   1747篇
  国内免费   342篇
耳鼻咽喉   26篇
儿科学   601篇
妇产科学   6982篇
基础医学   3033篇
口腔科学   195篇
临床医学   3080篇
内科学   1992篇
皮肤病学   246篇
神经病学   496篇
特种医学   369篇
外国民族医学   2篇
外科学   1090篇
综合类   4712篇
现状与发展   3篇
一般理论   4篇
预防医学   3903篇
眼科学   70篇
药学   2246篇
  42篇
中国医学   457篇
肿瘤学   255篇
  2024年   18篇
  2023年   372篇
  2022年   473篇
  2021年   1042篇
  2020年   1018篇
  2019年   1016篇
  2018年   928篇
  2017年   1104篇
  2016年   1245篇
  2015年   1039篇
  2014年   1837篇
  2013年   2641篇
  2012年   1517篇
  2011年   1851篇
  2010年   1474篇
  2009年   1278篇
  2008年   1253篇
  2007年   1211篇
  2006年   1224篇
  2005年   990篇
  2004年   917篇
  2003年   732篇
  2002年   547篇
  2001年   509篇
  2000年   420篇
  1999年   380篇
  1998年   260篇
  1997年   239篇
  1996年   235篇
  1995年   280篇
  1994年   193篇
  1993年   173篇
  1992年   135篇
  1991年   127篇
  1990年   121篇
  1989年   109篇
  1988年   111篇
  1987年   72篇
  1986年   68篇
  1985年   127篇
  1984年   93篇
  1983年   79篇
  1982年   72篇
  1981年   46篇
  1980年   59篇
  1979年   47篇
  1978年   32篇
  1977年   22篇
  1976年   21篇
  1975年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
目的 建立妊娠11~13+6周子宫动脉多普勒参数在低危人群中的正常参考值,同时评估其对不良妊娠结局的预测价值。方法 收集2019年6月至2021年6月于我院行产前超声检查的妊娠11~13+6周孕妇,根据妊娠结局分组。收集两侧子宫动脉多普勒指标,包括搏动指数(PI)、阻力指数(RI)、舒张早期是否有切迹,以及孕妇基本临床资料和胎儿出生信息,将以上相关参数进行统计学分析。结果 最终纳入800例孕妇,包括正常妊娠结局组740例和不良妊娠结局组60例。两组孕妇体质量指数(BMI)、分娩孕周和胎儿出生体质量比较,差异均有统计学意义(均P<0.05)。随着孕周的增加,子宫动脉两侧平均搏动指数(mPI)、平均阻力指数(mRI)和两侧舒张早期切迹检出率均呈逐渐下降的趋势。ROC曲线分析显示,mPI、mRI及两侧舒张早期切迹预测妊娠结局的曲线下面积(AUC)分别为0.542、0.574、0.521,三者联合预测妊娠结局的AUC为0.648;孕妇BMI、年龄mPI、mRI及两侧舒张早期切迹预测妊娠结局的AUC为0.751。结论 建立了低危人群在妊娠11~13+6周子宫动脉多普勒参数的正常参考值范围。在妊娠11~13+6周单纯应用子宫动脉多普勒参数预测妊娠结局的价值有限,将子宫动脉参数与临床相关指标结合可提高对不良妊娠结局的预测价值。  相似文献   
2.
Since the start of the COVID-19 pandemic, few studies have reported anaesthetic outcomes in parturients with SARS-CoV-2 infection. We reviewed the labour analgesic and anaesthetic interventions utilised in symptomatic and asymptomatic parturients who had a confirmed positive test for SARS-CoV-2 across 10 hospitals in the north-west of England between 1 April 2020 and 31 May 2021. Primary outcomes analysed included the analgesic/anaesthetic technique utilised for labour and caesarean birth. Secondary outcomes included a comparison of maternal characteristics, caesarean birth rate, maternal critical care admission rate along with adverse composite neonatal outcomes. A positive SARS-CoV-2 test was recorded in 836 parturients with 263 (31.4%) reported to have symptoms of COVID-19. Neuraxial labour analgesia was utilised in 104 (20.4%) of the 509 parturients who went on to have a vaginal birth. No differences in epidural analgesia rates were observed between symptomatic and asymptomatic parturients (OR 1.03, 95%CI 0.64–1.67; p = 0.90). The neuraxial anaesthesia rate in 310 parturients who underwent caesarean delivery was 94.2% (95%CI 90.6–96.0%). The rates of general anaesthesia were similar in symptomatic and asymptomatic parturients (6% vs. 5.7%; p = 0.52). Symptomatic parturients were more likely to be multiparous (OR 1.64, 95%CI 1.19–2.22; p = 0.002); of Asian ethnicity (OR 1.54, 1.04–2.28; p = 0.03); to deliver prematurely (OR 2.16, 95%CI 1.47–3.19; p = 0.001); have a higher caesarean birth rate (44.5% vs. 33.7%; OR 1.57, 95%CI 1.16–2.12; p = 0.008); and a higher critical care utilisation rate both pre- (8% vs. 0%, p = 0.001) and post-delivery (11% vs. 3.5%; OR 3.43, 95%CI 1.83–6.52; p = 0.001). Eight neonates tested positive for SARS-CoV-2 while no differences in adverse composite neonatal outcomes were observed between those born to symptomatic and asymptomatic mothers (25.8% vs. 23.8%; OR 1.11, 95%CI 0.78–1.57; p = 0.55). In women with COVID-19, non-neuraxial analgesic regimens were commonly utilised for labour while neuraxial anaesthesia was employed for the majority of caesarean births. Symptomatic women with COVID-19 are at increased risk of significant maternal morbidity including preterm birth, caesarean birth and peripartum critical care admission.  相似文献   
3.
ObjectiveWe aimed to investigate the prevalence and characteristics of non-accidental trauma (NAT) in children with polytrauma treated at level-I trauma centres (TC).Summary of backgroundData 6–10% Of children who present at the emergency department with injuries, sustain polytrauma. Polytrauma may result from either accidental (AT) or NAT, i.e. inflicted or neglect. The prevalence of NAT among children with polytrauma is currently unclear.MethodsThis is a retrospective study that included children (0–18 years) with an Injury Severity Score >15, who presented at one of the 11 Level-I trauma centers (TC) in the Netherlands between January 1, 2010 and January 1, 2016. Outcomes were classified based on the conclusions of the Child Abuse and Neglect-team. Cases in which conclusions were unavailable and there was no clear accidental cause of injuries were reviewed by an expert panel.ResultsThe study included 1623 children, 1452 (89%) were classified as AT, 171 (11%) as NAT; 39 (2,4%) inflicted and 132 (8,1%) neglect. Of pre-school aged children (<5 years) 41% sustained NAT (OR26.73, 95%CI 17.70–40.35), 35/342 (10%) inflicted and 104/342 (31%) neglect. Admission due to ‘cardiopulmonary arrest’ was the result of inflicted trauma (30% vs 0%,p < 0.001). NAT had a higher mortality rate (16% vs 10%, p = 0.006). Indicators of NAT were: (near-)drowning (OR10.74, 95%CI 5.94–19.41), burn (OR8.62, 95%CI 4.08–18.19) and fall from height (OR2.18, 95%CI 1.56–3.02).ConclusionsNAT was the cause of polytrauma in 11% of children in our nationwide level-I TC study; 41% of these polytrauma were the result of NAT experienced by preschool-aged children. Our data show the importance of awareness for NAT.  相似文献   
4.
目的 探讨滋肾育胎丸加减方预防抗磷脂抗体(ACA)阳性者不良妊娠结局的效果及机制研究。方法 选取2016年2月至2019年2月我院收治的89例ACA阳性,先兆性流产或有习惯性流产(RSA)史患者,将采用西医治疗的40例作为对照组,将采用西医联合滋肾育胎丸加减方治疗的49例作为观察组,比较两组中医证候疗效、中医证候积分、ACA-IgA、ACA-IgM、ACA-IgG、凝血指标[血小板聚集功能(PAF)、活化蛋白C(PC)、抗凝血酶(AT)、纤溶酶原激活抑制物-1(PAI-1)]、Th1/Th2细胞因子[干扰素γ(IFN-γ)、白介素-2(IL-2)、白介素-4(IL-4)、白介素-10(IL-10)]、妊娠结局、安全性。结果 治疗2周后检测ACA,观察组2例未降低,对照组11例未降低,观察组未降低患者占比低于对照组(P<0.05);观察组总有效率100.00%高于对照组85.00%(P<0.05);观察组治疗4周、7周后中医证候积分低于对照组(P<0.05);观察组治疗4周、7周后ACA-IgA、ACA-IgM、ACA-IgG低于对照组(P<0.05);观察组治疗4周、7周后PAF、PAI-1低于对照组,PC、AT高于对照组(P<0.05);观察组治疗4周、7周后IFN-γ、IL-2低于对照组,IL-4、IL-10高于对照组(P<0.05);观察组活产率95.92%高于对照组80.00%(P<0.05);组间不良反应总发生率比较,差异无统计学意义(P>0.05)。结论 动态监测ACA对滋肾育胎丸加减方精准应用具有指导意义,指导滋肾育胎丸加减方通过调理脏腑、气血、经络功能,改善先兆性流产或有RSA史患者临床症状及凝血因子指标,降低ACA水平,并可改善患者免疫耐受功能,提高胎儿活产率,且安全性高。  相似文献   
5.
6.
7.
8.
9.
目的对三位一体无缝隙护理在妊娠期高血压中的应用进行观察和分析。方法选择了2018年6月—2018年12月在本院进行了妊娠期高血压护理的60例患者进行研究,对所有患者均采取了三位一体无缝隙护理,对所有患者干预前后血压控制情况、生命质量评分以及心理健康评分进行对比。结果在进行干预之后,患者的血压控制情况、生命质量以及心理健康情况均显著优于干预之前,P<0.05差异有统计学意义。结论在对妊娠期高血压患者护理时,采取三位一体无缝隙护理措施可以对患者血压情况进行控制,缓解患者负面情绪,能够给予患者以及胎儿一定的保障。  相似文献   
10.
In 2008, Brazil's conditional cash transfer program expanded to cover a wider range of ages. Poor families are now given stipends for their children's school attendance up to age seventeen, whereas prior the maximum age was fifteen. Using a nationally representative household survey, we estimate the impact of this policy on teen fertility with a triple difference analysis on the fertility outcomes of treated cohorts vs. non-treated cohorts based on income eligibility, age eligibility, and timing of program implementation. We find a three percentage point drop in fertility among eligible teens within five years of program implementation. This offsets the difference in fertility between poor and non-poor teens. The impact is concentrated in urban areas, with no program effects found in rural areas. We are able to replicate these findings using National Birth Registry Data.  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