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   8540篇
  免费   520篇
  国内免费   26篇
耳鼻咽喉   126篇
儿科学   264篇
妇产科学   263篇
基础医学   878篇
口腔科学   145篇
临床医学   780篇
内科学   2230篇
皮肤病学   80篇
神经病学   836篇
特种医学   327篇
外科学   940篇
综合类   93篇
一般理论   6篇
预防医学   986篇
眼科学   158篇
药学   557篇
中国医学   2篇
肿瘤学   415篇
  2024年   7篇
  2023年   35篇
  2022年   58篇
  2021年   174篇
  2020年   83篇
  2019年   167篇
  2018年   190篇
  2017年   159篇
  2016年   145篇
  2015年   170篇
  2014年   279篇
  2013年   389篇
  2012年   629篇
  2011年   688篇
  2010年   377篇
  2009年   372篇
  2008年   567篇
  2007年   686篇
  2006年   639篇
  2005年   613篇
  2004年   576篇
  2003年   526篇
  2002年   464篇
  2001年   97篇
  2000年   64篇
  1999年   78篇
  1998年   103篇
  1997年   76篇
  1996年   59篇
  1995年   68篇
  1994年   47篇
  1993年   46篇
  1992年   47篇
  1991年   29篇
  1990年   36篇
  1989年   60篇
  1988年   35篇
  1987年   24篇
  1986年   23篇
  1985年   20篇
  1984年   30篇
  1983年   20篇
  1982年   23篇
  1981年   18篇
  1980年   16篇
  1979年   7篇
  1978年   14篇
  1977年   11篇
  1976年   9篇
  1971年   6篇
排序方式: 共有9086条查询结果,搜索用时 15 毫秒
31.
OBJECTIVE: The GRIF automated feedback system produces real-time comments on the appropriateness of diagnostic tests ordered by general practitioners (GPs) based on recommendations from accepted national and regional practice guidelines. We investigated the experiences of GPs with this system and, more specifically, with the recommendations produced by the system as well as their views on using this system in daily practice. SETTING: We tested the GRIF system in an experiment in a laboratory setting and in a daily practice trial. STUDY PARTICIPANTS: General practitioners. INTERVENTION: In the laboratory experiment, GPs used the GRIF system to assess the appropriateness of 30 request forms. Each of the GPs was confronted with requests they had submitted to the diagnostic unit of the hospital in the past. In the field trial, the GRIF system was applied during patient consultations for 1 year. MAIN OUTCOME MEASURES: We measured GPs' satisfaction with the system using a questionnaire, and also conducted group discussions (in the laboratory experiment) and in-depth interviews (in the field trial) to elicit GPs' opinions of and experiences with the system. In addition, we explored GPs' reasons for not accepting the comments offered by the GRIF system. RESULTS: The results show that the GPs in the laboratory experiment had more positive attitudes towards the system compared with participants in the field trial. All discussion groups and most of the GPs in the field trial regarded receiving the immediate feedback during the test ordering process as an important advantage. The most frequently mentioned reason to reject the recommendation was disagreement with the content and/or the recommendations in the practice guidelines. CONCLUSION: Apart from securing agreement on guideline content, a prerequisite for using GRIF in daily practice on a large scale is that more attention is paid to promotion of the guidelines and their adoption, and stimulation of a positive attitude towards the practice guidelines among the users.  相似文献   
32.
It is well established that visual display unit (VDU) operators complain of visual fatigue and visual stress during after-work hours. The present study was divided into two parts. In the first part, standard eye examinations were performed on a group of VDU workers (n = 32) and a control group (n = 15); those subjects who were found to have correct vision (n = 16 and 13, respectively) participated in the second part. The eye examinations revealed that on the average, the VDU workers suffered more than twice as many visual impairments as the controls. In those with correct vision, the near point of accommodation was measured at the beginning of the workday at the start of the week, and at the end of the workday, four days later. In the VDU group, the decrease in accommodation was uniformally distributed between zero and 1.0 diopter, whereas among the non-VDU workers, 77% of the decrease was between zero and 0.25 diopter. The dynamic range of accommodation in the VDU workers on the second examination was smaller than on the first. We conclude that some of the visual stress and visual fatigue that developed at work hindered visual activities after work.  相似文献   
33.
34.
IAFP     
  相似文献   
35.
OBJECTIVES: To directly compare the magnetic navigation system (MNS) guidewires with conventional guidewires in branching tortuous phantoms with operators of varying MNS and percutaneous coronary intervention experience. BACKGROUND: Vessel tortuosity, angulation, and side branches remain limiting factors in coronary interventions. The MNS addresses these limitations by precisely directing the tip of a magnetised guidewire in vivo aided by two permanent adjustable external magnets. METHODS: Crossing and fluoroscopy times of six operators were evaluated in five tortuous Perspex(R) phantom vessels in three consecutive attempts. Standard guidewire (SG) usage was unrestricted. Two 2nd generation magnetic guidewires (MG) were used. Failure was noted if the cross was unsuccessful within 5 min. RESULTS: The magnetic navigation was vastly superior to SG techniques with increasingly tortuous phantoms. It dramatically decreased both the crossing and fluoroscopy times with maximal reduction from 201.7 +/- 111 to 36.4 +/- 13 sec, P < 0.001 and 204.7 +/- 24 to 47.2 +/- 19 sec, P < 0.001, respectively. The MNS had a 98.8% procedural success rate compared to 68% with SG techniques. Moreover it considerably limited the amount of wire usage from 5.5 to 1.3. Operators with prior MG experience performed significantly better than those without, except in the simplest phantom where the difference was nonsignificant (33.8 +/- 13 sec vs. 41.7 +/- 17 sec, P = 0.2). CONCLUSION: MNS significantly reduces both the crossing and fluoroscopy times in tortuous coronary phantom models achieving excellent success rates with dramatic reductions in guidewire usage. Operators with prior MNS experience had an advantage over the inexperienced.  相似文献   
36.
Immunosuppression trends for solid organ transplantation have undergone a perceptible shift over the past decade. This period is of interest because it was during this time that the Food and Drug Administration (FDA) expanded the variety of medications to allow for alternatives in immunosuppressive management. An organ-by-organ review of SRTR data identifies several important trends. Antibody induction continues to be used for the majority of kidney (70%) , simultaneous pancreas-kidney (SPK, 79%) pancreas after kidney (PAK, 74%), and intestine recipients (74%). It is used for under half of thoracic organ recipients and remains uncommon for liver transplant recipients (20%). The type of antibody preparation utilized has shifted from muromonab-CD3 and horse ATG to rabbit ATG and monoclonal anti-IL-2 receptor antagonists. Calcineurin inhibitors continue to be used for maintenance immunosuppression for most recipients, although there has been a shift from cyclosporine to tacrolimus. A clear transition is apparent in the choice of antimetabolite from azathioprine to mycophenolate mofetil. Although corticosteroids continue to be used as maintenance immunosuppression for most recipients prior to discharge, there is evidence that efforts of steroid avoidance protocols are having an impact across all organs, as slight decreases in their use have been observed.  相似文献   
37.
In mycophenolate mofetil (MMF)-treated organ transplant recipients, lower mycophenolic acid (MPA) plasma concentrations have been found in cyclosporine (CsA) compared with tacrolimus (Tac)-based immunosuppressive regimens. We previously demonstrated that CsA decreases exposure to MPA and increases exposure to its metabolite MPA-glucuronide (MPAG), possibly by interfering with the biliary excretion of MPAG. To elucidate the role of the multidrug resistance-associated protein (Mrp)-2 in the interaction between MMF and CsA, we treated three groups of 10 Mrp2-deficient rats (TR- rat) for 6 days with either vehicle, CsA (8 mg/kg) or Tac (4 mg/kg) by oral gavage. Hereafter, co-administration with MMF (20 mg/kg) was started in all groups and continued through day 14. The 24-h MPA/MPAG area under the concentration-time curve (AUC) was determined after single (day 7) and multiple MMF doses (day 14). On both study days, there were no significant differences in the mean MPA and MPAG AUC between CsA and Tac-treated animals. We conclude that the pharmacokinetics of MMF are comparable in Mrp2-deficient rats receiving either CsA or Tac as co-medication. This finding suggests that CsA-mediated inhibition of the biliary excretion of MPAG by the Mrp2 transporter is the mechanism responsible for the interaction between CsA and MMF.  相似文献   
38.
39.
40.
I G Ron  I Reider  N Wigler  S Chaitchik 《Tumori》1992,78(6):397-402
Primary spinal epidural lymphoma (Stage I) is diagnosed predominantly late after a long prodromal phase of local back pain resulting in spinal cord compression. The use of CT and NMR images in the early stage of investigation and their analysis may help to diagnose these cases prior to the appearance of neurologic deficit. We report on 2 patients who presented with prolonged localized back pain with sudden symptoms of spinal cord compression. CAT scan and NMR imaging demonstrated the characteristic appearance of lymphoma. Decompressive laminectomy supported the diagnosis. Radiotherapy treatment to the region of the non-Hodgkin's lymphoma resulted in complete resolution. Thereafter, systemic chemotherapy with CHOP achieved a good response.  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