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   194篇
  免费   9篇
  国内免费   6篇
儿科学   8篇
妇产科学   3篇
基础医学   14篇
口腔科学   8篇
临床医学   9篇
内科学   49篇
皮肤病学   21篇
神经病学   3篇
特种医学   1篇
外科学   31篇
综合类   14篇
预防医学   11篇
眼科学   2篇
药学   18篇
中国医学   2篇
肿瘤学   15篇
  2019年   2篇
  2018年   1篇
  2017年   7篇
  2016年   3篇
  2014年   5篇
  2013年   9篇
  2012年   7篇
  2011年   6篇
  2010年   24篇
  2009年   19篇
  2008年   9篇
  2007年   9篇
  2006年   19篇
  2005年   4篇
  2003年   6篇
  2002年   3篇
  2001年   3篇
  2000年   4篇
  1998年   8篇
  1997年   13篇
  1996年   9篇
  1995年   5篇
  1994年   7篇
  1993年   1篇
  1992年   2篇
  1991年   2篇
  1990年   1篇
  1989年   3篇
  1988年   1篇
  1987年   1篇
  1986年   4篇
  1977年   1篇
  1976年   1篇
  1972年   1篇
  1959年   1篇
  1958年   2篇
  1957年   3篇
  1956年   2篇
  1955年   1篇
排序方式: 共有209条查询结果,搜索用时 170 毫秒
1.
本文旨在探讨吉林省延边地区自然环境和动物体表蜱类分布及其消长规律,掌握其携带发热伴血小板减少综合征布尼亚病毒(Severe fever with thrombocytopenia syndrome virus,SFTSV)状况及传播病毒能力。2016年4~9月份按月采集延边州所辖8个县(市)自然环境中生长的蜱虫和放牧动物体表蜱虫进行形态学分类,对其进行构成分析。对其中部分蜱虫分组进行SFTSV核酸检测。SFTSV核酸检测方法采用了Real time RT-PCR和RT-PCR相结合的方法。结果共采集蜱虫3 446只,其中森林革蜱763只,嗜群血蜱222只,日本血蜱639只,长角血蜱515只,全沟硬蜱1 014只,其他血蜱293只;全沟硬蜱(29.43%)和森林革蜱(22.14%)为本地优势种。长角血蜱在图们市(70.88%)和珲春市(40.59%)分布较多。对部分蜱虫(1605只)SFTSV Real time RT-PCR检测结果总最低感染率为1.81%,分种最低感染率分别为嗜群血蜱8.65%、日本血蜱4.53%、长角血蜱1.59%。序列分析结果表明,本文检测到的SFTSV病毒与我国其他省份从患者身上分离到的大部分SFTSV有高度一致性(99%)且与2012年从浙江患者血清中分离到的SFTSV、2013年韩国国家疾病预防控制中心从人身上采集的长角血蜱中分离到的SFTSV处于同一分枝,把该病毒命名为YBHC-TICK1-2016/CHINA。  相似文献   
2.
3.
4.
Direct international normalized ratio (INR) determination using certified INR plasmas was shown to improve precision and accuracy. We evaluated the utility of a multicalibrator in determining INR. INR values were measured in 493 blood samples from patients subjected to anticoagulation therapy (320) and control subjects (173). Study was performed using CA-7000 coagulation analyzer (Sysmex, Japan) with Thromborel S (Dade Behring, Germany). Direct INR values were obtained using PT-Multi Calibrator (Dade Behring) composed of five lyophilized calibrant plasmas. Conventional INR values were calculated from mean normal prothrombin time and instrument/reagent-specific international sensitivity index (ISI). We compared the difference between the INR results obtained with the two methods. The mean INR value of direct INR method was significantly higher than that of conventional method. The differences in values (direct INR – conventional INR) generated using the two methods increased in proportion to the INR values. Elevation of INR was observed in data obtained with the direct INR method, compared with conventional INR values. Accordingly, we conclude that direct INR method is more responsive than conventional method in determining INR.  相似文献   
5.
Background and objective: Reactivation of hepatitis B virus (HBV) is thought to be associated with immunosuppressive treatments, but insufficient information is available on the effect of corticosteroids. The aim of this study was to evaluate the risk of HBV reactivation in hepatitis B surface antigen‐seropositive patients with asthma or COPD, who were treated with systemic corticosteroids (SCS) in addition to inhaled corticosteroids (ICS). Methods: Patients with asthma or COPD (n = 198), who were hepatitis B surface antigen‐seropositive and had been treated with ICS, were identified retrospectively. To evaluate the additional effects of SCS, the SCS group was divided into those who received intermittent or continuous SCS (≥3 months of continuous SCS treatment), and into those who received low‐dose (≤20 mg/day of prednisolone) or medium‐to‐high‐dose SCS. The study outcome was HBV reactivation. Results: HBV reactivation occurred in 11.1% of patients in the SCS group, which was significantly higher than the reactivation rate in the ICS group. HBV reactivation was more frequent in the SCS group compared with the ICS group (OR 3.813, 95% CI: 1.106–13.145, P = 0.032), and in the continuous and medium‐to‐high‐dose SCS subgroups compared with the ICS group (OR 5.719, 95% CI: 1.172–27.905, P = 0.048 and OR 4.884, 95% CI: 1.362–17.511, P = 0.014, respectively). Conclusions: These results suggest that addition of SCS to ICS increases the risk of HBV reactivation, especially when SCS are administered chronically or at high doses.  相似文献   
6.
Summary. For patients with haemophilia, gastrointestinal (GI) bleeding is a life‐threatening complication and can be caused by the Helicobacter pylori infection. Among children with haemophilia who had visited with GI bleeding, the prevalence of H. pylori infection and the recurrence rate after H. pylori eradication was investigated. Seven children with haemophilia A with hematemesis (age: 5.3–17.0 years) were evaluated for the causes of GI bleeding and the detection of H. pylori. Gastroendoscopy was done to find the bleeding focus and for further evaluation including rapid urease test and mucosal biopsy. Four patients had dyspepsia and abdominal pain for several weeks or months prior to hematemesis. Three patients did not show any symptoms of bleeding. From gastroendoscopy, four patients were diagnosed as duodenal ulcer, one as H. pylori associated chronic gastritis and one as haemorrhagic gastritis. One patient showing a normal finding was diagnosed with adenoid haemorrhage after nasopharyngoscopy. Helicobacter pylori infection was found in four of six patients with GI bleeding (3, duodenal ulcer; 1, H. pylori associated chronic gastritis). The patients with H. pylori infection had an eradication treatment of triple therapy and no recurrence happened. In children with haemophilia, H. pylori should also be considered as an important cause of GI bleeding. The recurrence of the infection and GI bleeding can be prevented with eradication of H. pylori. Screening test for H. pylori would be needed in children with haemophilia in endemic area.  相似文献   
7.
Aims  We examined the impact of empowering work conditions on nurses' work engagement and effectiveness, and compared differences among these relationships in new graduates and experienced nurses.
Background  As many nurses near retirement, every effort is needed to retain nurses and to ensure that work environments are attractive to new nurses. Experience in the profession and generational differences may affect how important work factors interact to affect work behaviours.
Methods  We conducted a secondary analysis of survey data from two studies and compared the pattern of relationships among study variables in two groups: 185 nurses 2 years post-graduation and 294 nurses with more than 2 years of experience.
Results  A multi-group SEM analysis indicated a good fit of the hypothesized model. Work engagement significantly mediated the empowerment/effectiveness relationship in both groups, although the impact of engagement on work effectiveness was significantly stronger for experienced nurses.
Conclusions  Engagement is an important mechanism by which empowerment affects nurses feelings of effectiveness but less important to new graduates' feelings of work effectiveness than empowerment.
Implications for nursing management  Managers must be aware of the role of empowerment in promoting work engagement and effectiveness and differential effects on new graduates and more seasoned nurses.  相似文献   
8.
Although rate responsive pacing based on impedance minute ventilation (IMV) is now standard, there is almost no data confirming the relationship between IMV from an implanted pacemaker and measured minute ventilation (VE) during exercise. Nineteen completely paced adults implanted with Medtronic Kappa 400 pacemakers underwent symptom-limited maximal metabolic treadmill testing using a modified Minnesota Pacemaker Response Protocol. Minute ventilation (VE, L/min) was simultaneously measured using the flowmeter of a respiratory metabolic gas analysis system and the transthoracic impedance minute ventilation circuitry of the pacemaker. Correlation coefficients (r) were used to find the best fit line to describe the relationship between the two measurements. Mean (+/- SD) r values for the first, second, and third order polynomial equations and for log and exponential equations were: 0.92 +/- 0.08, 0.94 +/- 0.04, 0.95 +/- 0.04, 0.91 +/- 0.06, and 0.91 +/- 0.07, respectively. None of the r values were statistically different from the first order equation. Transthoracic IMV as measured by the Medtronic Kappa 400 is closely correlated to measured minute ventilation and is represented well by a first order (linear) equation.  相似文献   
9.
Background: We have studied the acute and long‐term efficacy of overlapping biphasic impulse (OLBI) stimulation for atrial pacing with VDD pacemakers and demonstrated the feasibility of DDD pacing in OLBI with diagonally arranged half‐ring (Half‐Ring) electrodes. We made two three‐dimensional computational analysis models to verify our clinical studies. Methods and Results: Model I was composed of a heart, a pacemaker, and a human body. Model II was a cube with dimensions of 20 by 20 by 20 mm quarried from Model I for the detailed study of current density distributions. Laplace's equation was solved using the finite element method and the current density J was calculated. For Model I, the distal and proximal voltages were ?10 V, 0 V in bipolar and ?5 V, +5 V in OLBI, using Ring electrodes. In Model II, the actual measurements of electrode impedances obtained from the clinical study (1,180 Ω for Ring and 630 Ω for Half‐Ring) were added to the analysis conditions. Model I showed that OLBI produced more concentrated current density distributions than those by bipolar. According to Model II, at the atrial myocardium position current density produced by Half‐Ring was larger than that by Ring electrodes, 70 μA/mm2 versus 30 μA/mm2 in OLBI configuration. It also indicated that even if electrode impedances were equal between Half‐Ring and Ring electrodes, the maximum current density produced by Half‐Ring would be greater than that by Ring electrodes. Conclusions: It was considered that OLBI configuration with Half‐Ring electrodes provides more effective current density distributions. (PACE 2010; 33:1063–1073)  相似文献   
10.
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