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   30118篇
  免费   1914篇
  国内免费   391篇
耳鼻咽喉   38篇
儿科学   654篇
妇产科学   7116篇
基础医学   3243篇
口腔科学   298篇
临床医学   3139篇
内科学   2380篇
皮肤病学   270篇
神经病学   643篇
特种医学   417篇
外国民族医学   2篇
外科学   1306篇
综合类   4872篇
现状与发展   3篇
一般理论   4篇
预防医学   4497篇
眼科学   89篇
药学   2451篇
  42篇
中国医学   489篇
肿瘤学   470篇
  2024年   61篇
  2023年   424篇
  2022年   815篇
  2021年   1202篇
  2020年   1079篇
  2019年   1075篇
  2018年   975篇
  2017年   1183篇
  2016年   1302篇
  2015年   1120篇
  2014年   1921篇
  2013年   2806篇
  2012年   1624篇
  2011年   1916篇
  2010年   1514篇
  2009年   1354篇
  2008年   1316篇
  2007年   1285篇
  2006年   1294篇
  2005年   1054篇
  2004年   981篇
  2003年   782篇
  2002年   609篇
  2001年   554篇
  2000年   450篇
  1999年   431篇
  1998年   321篇
  1997年   304篇
  1996年   288篇
  1995年   328篇
  1994年   227篇
  1993年   202篇
  1992年   155篇
  1991年   136篇
  1990年   133篇
  1989年   127篇
  1988年   125篇
  1987年   93篇
  1986年   87篇
  1985年   148篇
  1984年   107篇
  1983年   91篇
  1982年   91篇
  1981年   59篇
  1980年   70篇
  1979年   51篇
  1978年   40篇
  1977年   29篇
  1976年   27篇
  1975年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
BackgroundDespite indications for the removal of temporary inferior vena cava (IVC) filters, many filters are unintentionally left in place, predisposing patients to adverse outcomes.ObjectiveThis quality improvement study set out to determine the impact of an IVC filter retrieval protocol on filter retrieval rates and patients lost to follow-up for patients who had undergone placement of a temporary IVC filter.MethodsFollowing a quasi-experimental design, data of all consecutive patients who underwent insertion of a temporary IVC filter for a period of 24-month preprotocol and 12-month postprotocol were compared.ResultsFilter retrieval rates of eligible filters increased from 64.2% to 100%; patients lost to follow-up decreased from 35.9% to 0% (p < .01, both outcomes).ConclusionAdoption of a comprehensive IVC filter protocol by the service that implants these devices can improve filter retrieval rates and decrease patients being lost to follow-up.  相似文献   
2.
3.
4.
妊娠期甲状腺癌的诊治是目前甲状腺疾病诊治的热点和难点问题之一。妊娠期发现甲状腺癌对临床医生和孕妇都是一个极大的挑战,应通过多学科协作,尽快明确诊断,全面、合理的评估孕妇和胎儿的情况,选择最合适的治疗和随诊方式,避免对孕妇和胎儿产生副反应,维持正常孕期,获得最佳的治疗效果。  相似文献   
5.
目的 探讨腹腔镜下子宫双侧动脉阻断术联合清宫术治疗剖宫产瘢痕妊娠疗效及对内分泌的影响.方法 选择2011年1月至2015年12月剖宫产瘢痕妊娠患者57例,其中A组32例患者给予超声引导下清宫术治疗,B组25例患者给予腹腔镜下子宫双侧动脉阻断术联合清宫术治疗,比较两组患者出血量、住院时间、月经复潮时间、术后人绒毛膜促性腺激素(hCG)降至正常时间,并发症情况及术前(T0)、术后第1d(T1)、第3d(T2)神经内分泌激素水平.结果 ①B组患者出血量低于A组,住院时间、月经复潮时间短于A组,比较差异有统计学意义(t出血量=31.85,k院时间=9.36,t月经复t潮时间=16.37,均P<0.05);②B组患者并发症发生率为8.00%,低于A组的15.63%,比较差异有统计学意义(x2=9.35,P<0.05);③B组T1、T2血清COR、β-EP、GLU水平低于A组(CORF交互=17.67,β-EPF交互=132.36,6LUF交互=155.38,均P<0.05).结论 腹腔镜下子宫双侧动脉阻断术联合清宫术治疗剖宫产瘢痕妊娠微创优势明显,安全性高,对内分泌影响较轻.  相似文献   
6.
Geneticists have, for years, understood the nature of genome‐wide association studies using common genomic variants. Recently, however, focus has shifted to the analysis of rare variants. This presents potential problems for researchers, as rare variants do not always behave in the same way common variants do, sometimes rendering decades of solid intuition moot. In this paper, we present examples of the differences between common and rare variants. We show why one must be significantly more careful about the origin of rare variants, and how failing to do so can lead to highly inflated type I error. We then explain how to best avoid such concerns with careful understanding and study design. Additionally, we demonstrate that a seemingly low error rate in next‐generation sequencing can dramatically impact the false‐positive rate for rare variants. This is due to the fact that rare variants are, by definition, seen infrequently, making it hard to distinguish between errors and real variants. Compounding this problem is the fact that the proportion of errors is likely to get worse, not better, with increasing sample size. One cannot simply scale their way up in order to solve this problem. Understanding these potential pitfalls is a key step in successfully identifying true associations between rare variants and diseases.  相似文献   
7.
8.
9.
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   
10.
ObjectiveTo contemporize the Attitudes About Drug Abuse in Pregnancy questionnaire, keep the length of the modified scale brief to promote use, and test the psychometric properties of the modified scale among perinatal nurses.DesignCross-sectional survey.SettingFour hospitals in the Midwestern United States.ParticipantsRegistered nurses who worked in perinatal units (N = 440).MethodsWe collected data from participants using survey methods. Seven experts in perinatal substance use research and clinical care informed scale modifications. We used a split-sample design involving maternal–newborn units (labor, postpartum) and newborn-focused units (NICU, pediatrics). We evaluated construct validity using factor analysis and reliability using Cronbach’s alpha. We tested for differences between units using analysis of variance and Tukey’s post hoc honest significant difference test of pairwise differences.ResultsThe final modified scale included 13 items that loaded on one factor and showed internal consistency reliability in both samples (α = .88?.91). We found a statistically significant difference in mean score between NICU and pediatric units; however, the absolute difference was small and likely not clinically significant.ConclusionsThe Modified Attitudes About Drug Use in Pregnancy scale has initial evidence for validity and reliability, was updated to reflect current terminology in the field, and is a pragmatic tool for use in research.  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