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   1889篇
  免费   123篇
  国内免费   3篇
耳鼻咽喉   10篇
儿科学   106篇
妇产科学   27篇
基础医学   266篇
口腔科学   31篇
临床医学   204篇
内科学   349篇
皮肤病学   45篇
神经病学   250篇
特种医学   59篇
外国民族医学   1篇
外科学   202篇
综合类   87篇
一般理论   1篇
预防医学   209篇
眼科学   22篇
药学   100篇
中国医学   1篇
肿瘤学   45篇
  2022年   11篇
  2021年   32篇
  2020年   12篇
  2019年   27篇
  2018年   29篇
  2017年   29篇
  2016年   19篇
  2015年   22篇
  2014年   35篇
  2013年   65篇
  2012年   86篇
  2011年   77篇
  2010年   41篇
  2009年   35篇
  2008年   65篇
  2007年   92篇
  2006年   64篇
  2005年   74篇
  2004年   82篇
  2003年   75篇
  2002年   86篇
  2001年   62篇
  2000年   61篇
  1999年   51篇
  1998年   22篇
  1997年   16篇
  1996年   21篇
  1995年   16篇
  1993年   10篇
  1992年   39篇
  1991年   43篇
  1990年   39篇
  1989年   49篇
  1988年   42篇
  1987年   46篇
  1986年   38篇
  1985年   32篇
  1984年   36篇
  1983年   29篇
  1982年   15篇
  1981年   15篇
  1979年   30篇
  1978年   20篇
  1977年   20篇
  1976年   24篇
  1975年   15篇
  1974年   20篇
  1973年   29篇
  1972年   18篇
  1971年   17篇
排序方式: 共有2015条查询结果,搜索用时 15 毫秒
11.
12.
Cytomegalovirus (CMV) infection was diagnosed in 28% (n = 144) of 516 renal allograft recipients treated with cyclosporine-prednisone (CsA-Pred) immunosuppressive therapy. The majority of infections produced either asymptomatic (n = 37) or mild-to-moderate (n = 75) clinical disease, while 10% were lethal (n = 14). Transplantation from a seropositive donor to a seronegative recipient was associated with an increased incidence of (CMV) infection but did not predispose to more severe clinical disease. Similarly, donor source (cadaver [CAD] vs. living-related donor [LRD]), age greater than or equal to 45 years, and antecedent pulse steroid therapy for the treatment of acute rejection were not correlated with clinically more severe disease. An increase in serum creatinine to greater than or equal to 25% of preinfection nadir values occurred in association with CMV infection in 106 patients, returning to nadir values or below in 74.5% of these individuals. CMV infection did not impact on actual patient survival among recipients of LRD or CAD allografts or on actual 1-year HLA-haploidentical or HLA-identical LRD graft survival. In contrast, actual 1-year cadaveric graft survival was significantly lower among CMV-infected (n = 95) vs. uninfected (n = 198) patients (75.8% vs. 87.8%, P = .01). In association with the finding of reduced actual 1-year CAD graft survival, CMV-infected patients were found to be more predisposed to develop acute rejection episodes. Of the CMV-infected CAD graft recipients, 48.4% developed greater than or equal to 1 acute rejection episode during the first year following transplantation vs. 25.3% of their uninfected counterparts (P less than .001). The impact of CMV infection in CsA-Pred treated renal transplant recipients does not differ substantially from that reported historically in association with prednisone-azathioprine immunosuppressive therapy.  相似文献   
13.
14.
Background: Exercise is an important strategy with potential to improve recovery in older adults following a hip fracture.Purpose: The purpose of this study was to test the impact of a self-efficacy based intervention, the Exercise Plus Program, and the different components of the intervention, on self-efficacy, outcome expectations, and exercise behavior among older women post-hip fracture.Methods: Participants were randomized to one of four groups: exercise plus, exercise only, plus only (i.e., motivation), or routine care. Data collection was done at baseline (within 22 days of fracture), 2, 6, and 12 months post-hip fracture.Results: A total of 209 women were recruited with an average age of 81.0 years (SD=6.9). The majority was White (97.1%), was widowed (57.2%), and had a high school education (66.7%). Generalized Estimating Equations were used to perform repeated measures analyses. No differences in trajectories of recovery were observed for self-efficacy or outcome expectations. A statistically significant difference in the overall trajectory of time in exercise was seen (p<.001), with more time spent exercising in all three treatment groups.Conclusions: The study demonstrated that it was possible to engage these women in a home-based exercise program and that the plus only, exercise only, and the exercise plus groups all increased exercise. Support for this project was provided by National Institute on Aging grants R37 AG09901, R01-AG18668, R01 AG17082, and the Claude D. Pepper Older Americans Independence Center P60-AG12583.  相似文献   
15.
Transbronchial biopsy with the flexible fiberoptic bronchoscope is usually performed with the assistance of fluoroscopy in order to increase diagnostic yield and decrease the incidence of pneumothorax. We have compared the results of transbronchial biopsy performed with or without fluoroscopic guidance in patients with diffuse roentgenographic infiltrates who had or were suspected of having the acquired immunodeficiency syndrome. Neither the sensitivity for Pneumocystis carinii (88.5 versus 92%) nor the percentage of patients developing pneumothoraces after transbronchial biopsy (8.6 versus 11.1%) was significantly different in those patients who had the procedure without fluoroscopic guidance compared with those in whom fluoroscopy was used. There were no patients with significant hemorrhage or deaths in either group. This complication rate compares favorably with other reports of transbronchial biopsy in immunocompromised patients in which fluoroscopy was used. "Blind" transbronchial biopsy is a safe and effective diagnostic procedure in this patient population.  相似文献   
16.
Abnormality of chromosome 16 and its phenotypic expression   总被引:2,自引:0,他引:2  
An abnormality of chromosome 16 in which there is extra genetic material present on the short arm (46, XY, 16p+) has been identified. This chromosomal aberration was associated with multiple congenital anomalies, including mid-facial hypoplasia, arthrogryposis, and mental retardation. On the basis of the cytogenetic appearance and the phenotype of the patient, this may represent a partial 16 trisomy. Unlike most abnormalities of chromosome 16, this syndrome was compatible with life.  相似文献   
17.
These guidelines are intended to reduce the potential for serious or life-threatening reactions when clinical research is conducted. The following issues were addressed: identifying the risks involved in the research, providing adequate safeguards in the protocol design and during withholding of medication, anticipating risks, minimizing the chances for human error, providing resuscitative equipment sufficient to deal with the most serious anticipated life-threatening reactions, planning for medical support in case of a life-threatening emergency, and optimizing the use of medical personnel and expertise to handle emergency situations. The guidelines also discuss important general issues about protocol design and implementation and the human subject consent form, which should facilitate the approval of protocols by the governing institutional review board.The guidelines are not meant to be inflexible or applicable to all research situations. However, it is our hope that they will allow for clinical research to be conducted in a manner that affords the research subjects a high degree of protection from unnecessary and possibly fatal injuries.  相似文献   
18.
19.
20.
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