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   301篇
  免费   18篇
  国内免费   16篇
耳鼻咽喉   6篇
儿科学   17篇
妇产科学   4篇
基础医学   20篇
口腔科学   4篇
临床医学   45篇
内科学   77篇
皮肤病学   10篇
神经病学   5篇
特种医学   69篇
外科学   7篇
综合类   8篇
预防医学   11篇
眼科学   5篇
药学   31篇
肿瘤学   16篇
  2023年   2篇
  2021年   1篇
  2020年   3篇
  2019年   1篇
  2018年   3篇
  2017年   2篇
  2016年   3篇
  2015年   7篇
  2014年   7篇
  2013年   8篇
  2012年   4篇
  2011年   12篇
  2010年   7篇
  2009年   8篇
  2008年   6篇
  2007年   23篇
  2006年   4篇
  2005年   6篇
  2004年   3篇
  2003年   3篇
  2002年   5篇
  2001年   5篇
  2000年   5篇
  1999年   5篇
  1998年   14篇
  1997年   20篇
  1996年   22篇
  1995年   18篇
  1994年   14篇
  1993年   10篇
  1992年   4篇
  1991年   2篇
  1990年   13篇
  1989年   19篇
  1988年   13篇
  1987年   11篇
  1986年   3篇
  1985年   4篇
  1984年   1篇
  1983年   3篇
  1982年   7篇
  1981年   5篇
  1979年   3篇
  1978年   3篇
  1977年   4篇
  1976年   3篇
  1975年   5篇
  1959年   1篇
排序方式: 共有335条查询结果,搜索用时 0 毫秒
41.
42.
Background Colorectal cancer (CRC) is one of the most common types of cancer in European countries and associated with a high mortality rate. A 16% relative risk reduction (RRR) of mortality was found in a meta‐analysis based on four randomized controlled trials (RCT) on CRC screening. The aim of this paper was to scrutinize these trials for potential biases and assess their influence on the screening trials. Methods The four RCTs were reviewed based on the principles of ‘Critical Appraisal of the Medical Literature’. Principal investigators of the four RCTs were contacted to clarify uncertainties in their study. Data were collected from The Danish Data Archives. Authors of the Cochrane review were contacted. Results Six biases were identified, of which five favour screening. Three of the biases identified were specific to CRC screening: type of diagnostic method, place of surgery and diagnostic delay. Conclusion The 16% RRR in CRC mortality found in the updated Cochrane review's meta‐analysis is overestimated.  相似文献   
43.
Twenty-six patients with progressive Hodgkin's disease after conventional chemotherapy received intensive chemoradiotherapy and autologous bone marrow transplantation (ABMT); 19 also received additional involved-field radiotherapy. Twenty-one patients [81%, 95% confidence intervals (CI) 61% to 94%] attained complete (n = 18) or partial responses. Ten patients (38%, 95% CI 20% to 59%) are disease- free a median of 4.5 years later (range 3.5 to 7.0 years), including seven patients with continuous complete responses. The likelihood of overall response was not significantly influenced by any clinical or treatment variable examined. However, there was a trend favoring patients with higher Karnofsky scores, and higher scores were associated with attainment of complete responses (P = .06 and P = .02, respectively, Mann-Whitney U test). Both higher Karnofsky scores and shorter durations of disease before transplantation were associated with improved survival in a stepwise Cox multivariate analysis. The chief cause of failure was progression at sites previously involved with Hodgkin's disease. No patient relapsed in the marrow, and two of three patients with a history of marrow involvement with Hodgkin's disease achieved durable complete responses after transplantation. These data suggest that inadequate pretransplant conditioning, and not the reinoculation of occult tumor cells in the autologous marrow, caused most relapses. Fatal treatment-related toxicity occurred in six patients. Three patients died of idiopathic interstitial pneumonitis; each had previously received local mediastinal irradiation before intensive chemoradiotherapy. Intensive chemoradiotherapy and ABMT produces durable responses in some patients with Hodgkin's disease incurable with conventional therapy. Use of such therapies at the first sign of failure with conventional chemotherapy and development of more effective conditioning regimens should further improve results.  相似文献   
44.
Abelson  HT; Gorka  C; Beardsley  GP 《Blood》1979,53(1):116-121
Normal human platelets were shown to contain the enzyme dihydropteridine reductase. The enzyme was not found in a variety of other cells of hematogenous origin. Partial purification and kinetic and physical data indicated that the platelet enzyme is similar to that previously characterized from liver. Dihydropteridine reductase is important for the regeneration of tetrahydrobiopterin, a required cofactor in hydroxylation reactions involved in biogenic amine formation. The presence of the enzyme may indicate that some synthesis de novo of serotonin and/or catecholamines occurs in platelets, as opposed to a purely storage and transport function. In addition, screening for hyperphenylalaninemia due to dihydropteridine reductase deficiency may become feasible by assaying platelets for enzyme activity.  相似文献   
45.
Patellar tendinitis is a well-described clinical entity that usually responds well to conservative treatment. However, a subset of patients continue with symptoms despite exhaustive nonoperative means. The objective of the study was to review the treatment course and operative results of seven patients (eight knees) with chronic patellar tendinitis treated surgically. Five (70%) of these patients were either professional or collegiate athletes. The average age was 30 years (range, 20 to 45 years). Duration of symptoms averaged 1.4 years (range, 3 months to 4 years) before surgical correction. Operative treatment included knee arthroscopy and open repair consisting of excision of degenerated tissue and stimulation of a healing response of the patellar tendon pathology. Operative findings and pathology reports consistently showed marked fibrotendinous degeneration. Follow-up averaged 3.6 years (range, 4 months to 8.5 years). Outcomes were measured subjectively with SF36 results and objectively with Biodex testing (Biodex, Shirley, NY) and return to previous level of competition. Overall, 86% of patients achieved an excellent result and 14% had a fair result. We recommend operative intervention in a patient with chronic patellar tendinitis who does not improve with well-supervised, comprehensive conservative treatment. (Arthroscopy 1998 Nov-Dec;14(8):836-9.)  相似文献   
46.
Low-artifact intravascular devices: MR imaging evaluation   总被引:2,自引:0,他引:2  
Flow-phantom magnetic resonance (MR) imaging, with use of both spin-echo (SE) and gradient-echo (GRE) techniques at 1.5 T, was performed on the percutaneous Greenfield (beta-III titanium alloy [TMA wire]), Amplatz (MP32-N alloy), and Simon nitinol filters and TMA wire facsimiles of the bird's nest, Gunther, new retrievable, and Amplatz vena caval filters. SE imaging allowed detection of thrombi as small as 5 X 5 mm trapped within the percutaneous Greenfield, Simon nitinol, and TMA-wire facsimile filters; with the MP32-N Amplatz filter, a larger volume of thrombus (10 X 20-mm clots) was necessary for clot detection. GRE imaging allowed detection of intraluminal tilting of the percutaneous Greenfield and facsimile Amplatz (TMA-wire) filters. GRE imaging was useful for demonstrating postfilter turbulence due to clots, which was greatest for the Amplatz filter. Imaging of facsimile vascular devices made of tantalum or TMA wire did not cause the severe "black-hole" MR artifacts typical of the stainless-steel devices. SE and GRE imaging were very useful for determining caval patency in two patients with previously placed Mobin-Uddin filters. Noninvasive MR evaluation of blood vessels in the presence of a variety of low-artifact intravascular devices appears feasible.  相似文献   
47.
48.
目的:通过对老年人进行血浆溶血磷脂酸和磷脂酸的筛检,从而认识血浆溶血磷脂酸和磷脂酸在血栓预防中的作用。方法:对2004-04/07期间的1657名和2005-04/07期间的1748名离休干部进行血浆溶血磷脂酸和磷脂酸含量测定,并对溶血磷脂酸>3.0μmol/L和磷脂酸>5.0μmol/L的阳性人员进行药物干预。同时,选择2004年溶血磷脂酸和/或磷脂酸阳性人员119人,随机分为两组:①干预组(n=72):男63人,女9人,平均年龄78岁。口服阿司匹林100mg/d,持续1个月。②对照组(n=47):男42人,女5人,平均年龄76岁。干预后,测定两组血浆中溶血磷脂酸和磷脂酸的含量。结果:纳入对象全部进入结果分析。2005年磷脂酸及血浆溶血磷脂酸 磷脂酸阳性率均明显低于2004年(P<0.01),尤其是磷脂酸的阳性率降低的更为明显。2005年血浆溶血磷脂酸和磷脂酸的平均值均明显低于2004年(P<0.01)。干预组干预后血浆溶血磷脂酸和磷脂酸明显低于干预前及对照组(P<0.01)。结论:①血浆溶血磷脂酸和磷脂酸的测定可作为血栓预警和了解抗血栓药物疗效的一种手段。②阿司匹林干预后,血浆溶血磷脂酸和磷脂酸的含量均降低,可作为一种降低缺血性疾病发生率的有效途径。  相似文献   
49.
目的:通过分析精神分裂症患者中枢多巴胺代谢产物-血浆高香草酸浓度(pHVA)与临床指征的关系,进一步探讨多巴胺神经递质及其药物治疗在精神分裂症的作用。方法在46例长期药物治疗、58例未治疗精神分裂症患者中,采用高液相色谱连接电化学分析仪测定PHVA;测前评定阳性症状量表(SAPS)和阴性症状量表(SANS)。结果(1)与62例健康对照组比,治疗组PH-VA显著减低,未治疗组显著增高,以阴性症状组为  相似文献   
50.
The objective of this study was to investigate the management of suspected fungal nail infections by general practitioners (GPs) and determine whether guidance is sought when submitting specimens for investigation or treating cases. Questionnaires were sent to all GPs (n = 2420) served by five Health Protection Agency (HPA) collaborating laboratories in the South West of England. A total of 769 GPs responded – topical and oral antifungals were never used by 29% and 16% of GPs respectively. When antifungals were prescribed, topicals were normally given because of the severity of infection (32%); Amorolofine (53%) was the preferred choice. Oral antifungals were most often prescribed after receipt of a laboratory report (77%); Terbinafine was the preferred choice (86%). Seventy percent of GPs would only treat a suspected nail infection with oral antifungals after sending a sample for investigation, yet 27% never waited for a microscopy report before prescribing oral antifungal treatment. GPs routinely send specimens from suspected fungal nail infections for microbiological investigation, yet treatment is often prescribed before a result is received. With clinical signs of fungal infections often non‐specific, GPs should rely on laboratory results before prescribing expensive and lengthy antifungal treatments. Laboratories could further reduce antifungal use by including guidance on microscopy and culture reports.  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