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   2860篇
  免费   386篇
  国内免费   39篇
耳鼻咽喉   43篇
儿科学   243篇
妇产科学   32篇
基础医学   540篇
口腔科学   40篇
临床医学   423篇
内科学   416篇
皮肤病学   18篇
神经病学   352篇
特种医学   92篇
外科学   278篇
综合类   205篇
预防医学   277篇
眼科学   23篇
药学   93篇
  1篇
中国医学   18篇
肿瘤学   191篇
  2024年   7篇
  2023年   114篇
  2022年   100篇
  2021年   141篇
  2020年   167篇
  2019年   160篇
  2018年   127篇
  2017年   116篇
  2016年   153篇
  2015年   127篇
  2014年   229篇
  2013年   247篇
  2012年   149篇
  2011年   168篇
  2010年   122篇
  2009年   125篇
  2008年   120篇
  2007年   126篇
  2006年   92篇
  2005年   73篇
  2004年   76篇
  2003年   43篇
  2002年   44篇
  2001年   38篇
  2000年   41篇
  1999年   36篇
  1998年   33篇
  1997年   39篇
  1996年   31篇
  1995年   22篇
  1994年   28篇
  1993年   22篇
  1992年   22篇
  1991年   20篇
  1990年   21篇
  1989年   14篇
  1988年   9篇
  1987年   3篇
  1986年   9篇
  1985年   10篇
  1984年   11篇
  1983年   7篇
  1982年   6篇
  1981年   7篇
  1980年   6篇
  1979年   13篇
  1978年   3篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
排序方式: 共有3285条查询结果,搜索用时 359 毫秒
41.
BackgroundImproved perioperative care for total joint arthroplasty (TJA) procedures has resulted in decreased hospital length of stay (LOS), including effective discharge on postoperative day (POD) 1 in many patients. It remains unclear what contributes to discharge delay in patients that are not discharged on POD 1. This study investigated factors associated with delayed discharge in patients whose original planned discharge was on POD 1.MethodsA retrospective cohort of 451 patients who underwent a hip or knee TJA procedure from April 2015 to March 2018 with planned discharge on POD 1 was analyzed. Patient characteristics included demographics, lab values, course of treatment, procedure, Charlson Comorbidity Index (CCI), complications, and other factors. Statistical regression was used to identify factors associated with delayed discharge; odds ratios (OR) were calculated for significant factors (α = 0.05).ResultsOf those studied, 70/451 (15.5%) experienced a delay from the planned POD 1 discharge. An increased likelihood of delayed discharge was associated with a nonhome discharge (P < .001, OR = 8.72 [95% CI: 4.22-18.06]) and higher CCI (P = .034, OR = 1.16 [95% CI: 1.01-1.32]). Inpatient physical therapy on the day of surgery was found to significantly correlate with successful discharge on POD 1 (P = .004, OR = 0.44 [95% CI: 0.25-0.77]).ConclusionMost patients can be discharged on POD 1 after TJA. Physical therapy on the day of surgery increased the likelihood of patients being discharged on POD 1. Those with a higher CCI and a nonhome discharge were more likely to have a discharge delay. This information can help surgeons counsel patients and prepare for postoperative care.  相似文献   
42.
43.
In this study, we aimed to examine the diagnostic yield achieved by applying a trio approach in exome sequencing (ES) and the interdependency between the clinical specificity in families with neurodevelopmental delay. Thirty-seven families were recruited and trio-ES as well as three criteria for estimating the clinical phenotypic specificity were suggested and applied to the underaged children. All our patients showed neurodevelopmental delay and most of them a large spectrum of congenital anomalies. Applying the pathogenicity guidelines of the American College of Medical Genetics (ACMG), likely pathogenic (29.7%) and pathogenic variants (8.1%) were found in 40,5% of our index patients. Additionally, we found four variants of uncertain significance (VUS; according to ACMG) and two genes of interest (GOI; going beyond ACMG classification) (GLRA4, NRXN2). Spastic Paraplegia 4 (SPG4) caused by a formerly known SPAST variant was diagnosed in a patient with a complex phenotype, in whom a second genetic disorder may be present. A potential pathogenic variant linked to severe intellectual disability in GLRA4 requires further investigation. No interdependency between the diagnostic yield and the clinical specificity of the phenotypes could be observed. In consequence, trio-ES should be used early in the diagnostic process, independently from the specificity of the patient.  相似文献   
44.
Partial monosomy of 6q resulting from an interstitial deletion of bands q16----q22 was found in a 12-year-old boy manifesting mental retardation, seizure disorder, and dysmorphic features. The correlation of phenotypic expression and specific long arm deletions of chromosome No. 6 is discussed.  相似文献   
45.
Dual chamber pacing (DDD) maintains atrioventricular (AV) sequence; AV delay programmability modifies the relationship between atrial and ventricular contraction. To evaluate the hemodynamic effects of such a modification, ten patients with a DDD unit for complete AV block were studied by time-motion (M-mode) and Doppler echocardiography during inhibited ventricular pacing (VVI), atrial-triggered ventricular pacing (VDD) and atrioventricular sequential pacing (DVI) at different AV delay (90, 140, 190, 240 msec). A significant improvement in stroke volume (SV) (15%-20%, P less than 0.05) was seen during DDD versus VVI pacing; no changes, however, were observed in the same patient with different AV delay or during DVI versus VDD pacing. These data suggest that programming of AV delay does not affect systolic performance at rest; longer diastolic filling times recorded during DDD pacing with "short" AV delay (90-140 msec) do not seem to be a hemodynamically relevant epi-phenomenon of PM programming.  相似文献   
46.
We conducted a case-control study to examine relationships between potential risk factors in women's prenatal occupational histories and subsequent mental retardation in their 10-year-old children. Children with mental retardation (intelligence quotient less than 71) were identified from special education records maintained by the public school systems in the metropolitan Atlanta area and from records of various medical and social service agencies serving children with special needs. Control children were chosen from the rosters of 10-year-olds who were enrolled in regular education classes in the local public school systems. To obtain occupational histories, sociodemographic data, and other information, we interviewed 352 natural mothers (67%) of 525 case children and 408 natural mothers (64%) of 636 control children. We computed odds ratios for each of 25 selected occupation, industry, and agent categories controlling for maternal education, birth order, and race. Most comparisons yielded odds ratios that were not indicative of unusual risks, but we did find lower than expected risks among children of teachers and health-care professionals. We also found a strong, positive association between mental retardation and maternal employment in the textile and apparel industries. The findings are useful for planning the direction of future studies of childhood cognitive ability to focus on specific parental occupations or industries. © 1993 Wiley-Liss, Inc.
  • 1 This article is a US Government work and, as such, is in the public domain in the United States of America.
  •   相似文献   
    47.
    目的:提出一种关于RPM放疗呼吸门控系统束流时间延迟性能的参考质控方法,给出参考条件下VB与EDGE加速器的时间延迟测量结果。方法:首先设计梯形质控呼吸曲线并加载运动模体,利用定位CT扫描由运动模体驱动的W-L模体,然后设计用于束流出束和截止延迟测量的两类质控计划,最后在加速器上执行质控计划,使用EPID采集模体的静态参考图像与运动测量图像,通过分析致密金属球在运动图像和参考图像中的位置差,反推束流的时间延迟,分别在VB与EDGE两台加速器上做方法验证。结果:VB与EDGE加速器的束流出束时间延迟均小于100 ms,截止时间延迟基本一致,VB加速器约为14 ms,EDGE约为22 ms。10FFF各剂量率的出束时间延迟基本一致,而6FFF、6 MV和10 MV则随剂量率的变化略有增加。4个能量各剂量率的束流截止时间延迟均较小且相对一致,部分能量有随剂量率变大而延迟缩小的趋势。结论:本研究提出的RPM束流时间延迟参考质控方法和条件具有较高的测量可信度和较强的临床实操性,测量结果表明RPM呼吸门控系统响应灵敏,研究结果为呼吸门控系统的时间延迟质控提供了重要的方法学指导与数据参考。  相似文献   
    48.
    To delineate further the clinical phenotype of Lamb–Shaffer Syndrome (LSS) 16 unpublished patients with heterozygous variation in SOX5 were identified either through the UK Decipher database or the study team was contacted by clinicians directly. Clinical phenotyping tables were completed for each patient by their responsible clinical geneticist. Photos and clinical features were compared to assess key phenotypes and genotype–phenotype correlation. We report 16 SOX5 variants all of which meet American College of Medical Genetics/Association for Clinical Genomic Science ACMG/ACGS criteria class IV or V. 7/16 have intragenic deletions of SOX5 and 9/16 have single nucleotide variants (including both truncating and missense variants). The cohort includes two sets of monozygotic twins and parental gonadal mosaicism is noted in one family. This cohort of 16 patients is compared with the 71 previously reported cases and corroborates previous phenotypic findings. As expected, the most common findings include global developmental delay with prominent speech delay, mild to moderate intellectual disability, behavioral abnormalities and sometimes subtle characteristic facial features. We expand in more detail on the behavioral phenotype and observe that there is a greater tendency toward lower growth parameters and microcephaly in patients with single nucleotide variants. This cohort provides further evidence of gonadal mosaicism in SOX5 variants; this should be considered when providing genetic counseling for couples with one affected child and an apparently de novo variant.  相似文献   
    49.
    脑梗塞患者治疗时间延误原因及对策   总被引:5,自引:0,他引:5  
    为探讨脑梗塞患者治疗时间的延误原因和对策,对河北、内蒙古部分地区脑梗塞患者治疗时间延误的原因进行了调查分析。共调查了脑梗塞患者1048例,在6小时内接受治疗的人数为326例,占31.11%;在24小时内,接受治疗的人数为566例,占54.01%;在25小时后,接受治疗的人数为482例,占45.99%。脑梗塞患者治疗延误时间为23.55小时,其院前的延误时间为21.49小时,占91.25%,院后的延误时间为2.06小时,占8.75%。调查发现,对脑梗塞患者实施早期治疗,必须在社区内进一步加强脑梗塞症状学和及早诊治意义的科普教育;提高医务人员对脑梗塞诊治水平和治疗紧迫性的认识,建立和完善医院的快速反应系统。只有这样,脑梗塞的早期治疗,才会有根本性的改善  相似文献   
    50.
    The aim of the present study was to investigate whether cisplatin would enhance the radioresponse of a human tumour xenograft when given in different schedules combined with accelerated fractionated radiation therapy. A human squamous carcinoma of the hypopharynx, FaDu, was grown in the thigh of athymic nude mice. Tumours were exposed to twice-daily 2-Gy fractions, applied 6 h apart over 2 weeks, 5 days a week, alone or combined with cisplatin given at maximally tolerated doses in three different schedules: (1) i.p. as a single bolus (SB) or (2) i.p. as a daily bolus at 30 min before the first daily radiation fraction or (3) s.c. as a continuous infusion through a mini-osmotic pump over 13 days, commencing 24 h prior to the first daily radiation fraction. The end point for the study was tumour growth delay (TGD), calculated as the difference between the delay in regrowth to 200% of the initial tumour size in treated versus control mice. SB cisplatin plus radiation showed only an additive effect on TGD, whereas daily-bolus and continuous-infusion cisplatin demonstrated a greater than additive effect when combined with accelerated fractionated radiation in this human tumour model. Cisplatin appears to be especially beneficial as a radiation enhancer when given throughout the course of radiation. Received: 15 December 1996 / Accepted: 25 March 1997  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