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   1929篇
  免费   124篇
  国内免费   16篇
耳鼻咽喉   15篇
儿科学   67篇
妇产科学   47篇
基础医学   192篇
口腔科学   59篇
临床医学   192篇
内科学   322篇
皮肤病学   56篇
神经病学   131篇
特种医学   58篇
外科学   276篇
综合类   50篇
一般理论   1篇
预防医学   117篇
眼科学   80篇
药学   235篇
中国医学   32篇
肿瘤学   139篇
  2024年   2篇
  2023年   38篇
  2022年   43篇
  2021年   119篇
  2020年   81篇
  2019年   154篇
  2018年   109篇
  2017年   79篇
  2016年   97篇
  2015年   78篇
  2014年   101篇
  2013年   123篇
  2012年   156篇
  2011年   173篇
  2010年   82篇
  2009年   77篇
  2008年   90篇
  2007年   86篇
  2006年   83篇
  2005年   43篇
  2004年   39篇
  2003年   24篇
  2002年   25篇
  2001年   14篇
  2000年   7篇
  1999年   12篇
  1998年   4篇
  1997年   4篇
  1996年   3篇
  1995年   4篇
  1994年   3篇
  1993年   3篇
  1992年   19篇
  1991年   13篇
  1990年   9篇
  1989年   11篇
  1988年   12篇
  1987年   5篇
  1986年   3篇
  1985年   3篇
  1984年   3篇
  1983年   9篇
  1982年   4篇
  1981年   2篇
  1979年   5篇
  1975年   4篇
  1974年   4篇
  1972年   1篇
  1971年   4篇
  1965年   2篇
排序方式: 共有2069条查询结果,搜索用时 31 毫秒
11.
12.
BackgroundAcute exacerbations of chronic obstructive pulmonary disease (AECOPD) are serious complications that often require immediate intervention in an emergency department (ED). The aim of this study was to investigate the effect of intravenous magnesium sulphate as an adjuvant in the treatment of AECOPD in the ED.MethodsIn a double-blind, randomized clinical trial, a total of 60 patients with AECOPD presenting to the ED of Imam Khomeini Hospital in Sari, Iran, were included. The study was conducted between September 2016 and February 2018. Eligible patients were randomly allocated into two groups of intervention and control. Patients in the intervention and control groups received intravenous infusion of magnesium sulfate (2 gr) or normal saline over 30 minutes, respectively. For all patients, Borgdyspnea score, forced expiratory volume in one second (FEV1) result and clinical variables of interest were evaluated before the beginning of the intervention, and also 45 minutes and 6 hours after the commencement of intervention.ResultsRegardless of time of evaluation, pulse rate (PR), respiratory rate (RR) and Borg score in intervention group was lower than control group. Also, FEV1 and SPO2 were greater in intervention group compared to control group. However, these differences were not statistically significant (between-subject differences or group effect) (p<0.001). The trends of FEV1, SPO2, PR, RR and Borg score were similar between two groups of study (no interaction effect; P>0.05).ConclusionAccording to the results of this study, it seems that using intravenous magnesium sulfate has no significant effect on SPO2, FEV1, RR, and PR of patients with AECOPD who presented to ED.  相似文献   
13.
This study investigated the impact of the administration of HAART and anti-Koch's, singly and in combination, on sexual competence and birth statistics. Adult male Wistar rats were randomised into distilled water-treated control, HAART-treated, anti-Koch's-treated and HAART + anti-Koch's-treated groups. The 56-day oral treatment led to impaired sexual competence evident by significantly reduced motivation to mate, prolonged latencies of mount, intromissions, ejaculations and post-ejaculatory interval, as well as reduced frequencies of mount, intromissions and ejaculations. This was accompanied by significant reductions in penile erection reflex and penile grooming. HAART and anti-Koch's, when administered singly or in combination, also led to significant reductions in the circulatory follicle-stimulating hormone, luteinizing hormone, testosterone and intratesticular testosterone, but a significant rise in prolactin. Also, HAART and/or anti-Koch's significantly reduced sperm count, sperm motility, sperm viability and spermatozoa with normal morphology. Furthermore, HAART and anti-Koch's, separately or in combination, significantly lowered fertility capacity, litter size and litter weight and offspring survival. The deleterious effects of these drugs were more pronounced when combined. Findings of the present study revealed that HAART and/or anti-Koch's impair sexual competence via a testosterone-dependent hyperprolactinemia-mediated mechanism. These events are associated with reduced fertility capacity, poor sperm quality and lowered offspring survival.  相似文献   
14.
15.
BackgroundWork-related musculoskeletal injuries have been increasingly recognized to affect surgeons. It is unknown whether such injuries also affect surgical trainees. The purpose of this study was to assess the ergonomic risk of surgical trainees as compared with that of experienced surgeons.MethodsErgonomic data were recorded from 9 surgeons and 11 trainees. Biomechanical loads during surgery were assessed using motion tracking sensors and electromyography sensors. Demanding and static positions of the trunk, neck, right/left shoulder, as well as activity from the deltoid and trapezius muscles bilaterally were recorded. In addition, participants reported their perceived discomfort on validated questionnaires.ResultsA total of 87 laparoscopic general surgery cases (48 attendings and 39 trainees) were observed. Both trainees and attendings spent a similarly high percentage of each case in static (>60%) and demanding positions (>5%). Even though residents reported overall more discomfort, all participants shared similar ergonomic risk with the exception of trainees’ trunk being more static (odds ratio: –11.42, P = .006).ConclusionSurgeons are prone to ergonomic risk. Trainees are exposed to similar postural ergonomic risk as surgeons but report more discomfort and, given that musculoskeletal injuries are cumulative over time, the focus should be on interventions to reduce ergonomic risk in the operating room.  相似文献   
16.
Bulletin of Environmental Contamination and Toxicology - To evaluate the effectiveness of orange peels (OP) and banana peels (BP) in reducing the toxicity of silver nanoparticles (Ag-NPs),...  相似文献   
17.
18.
19.
20.
Approximately 6.3 million fractures occur each year in the United States alone. Accurately monitoring the progression of fracture healing is essential to be able to advise patients when it is safe to return to normal activity. The most common method used to confirm and monitor fracture healing is the acquisition of multiple radiographic images over the many months required for healing. This imaging method uses large expensive equipment and exposes patients to high levels of ionizing radiation. In the study described here, we tested another technology for monitoring fracture healing that could minimize the need for multiple radiographic images. We tested a piezoelectric transducer fixed to the surface of a bone that uses electromechanical impedance spectroscopy to measure simulated fractures and transmits the measurement data to an acoustic receiver located externally on the skin surface.  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