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   1570篇
  免费   113篇
  国内免费   20篇
耳鼻咽喉   13篇
儿科学   50篇
妇产科学   20篇
基础医学   223篇
口腔科学   16篇
临床医学   199篇
内科学   283篇
皮肤病学   35篇
神经病学   112篇
特种医学   234篇
外科学   157篇
综合类   40篇
预防医学   101篇
眼科学   49篇
药学   88篇
中国医学   2篇
肿瘤学   81篇
  2022年   8篇
  2021年   20篇
  2020年   13篇
  2019年   10篇
  2018年   24篇
  2017年   20篇
  2016年   26篇
  2015年   25篇
  2014年   48篇
  2013年   55篇
  2012年   64篇
  2011年   54篇
  2010年   66篇
  2009年   44篇
  2008年   66篇
  2007年   68篇
  2006年   65篇
  2005年   49篇
  2004年   37篇
  2003年   53篇
  2002年   48篇
  2001年   42篇
  2000年   45篇
  1999年   42篇
  1998年   47篇
  1997年   44篇
  1996年   43篇
  1995年   30篇
  1994年   30篇
  1993年   19篇
  1992年   24篇
  1991年   36篇
  1990年   24篇
  1989年   49篇
  1988年   34篇
  1987年   35篇
  1986年   30篇
  1985年   26篇
  1984年   15篇
  1983年   35篇
  1982年   16篇
  1981年   20篇
  1980年   17篇
  1979年   18篇
  1978年   17篇
  1977年   14篇
  1976年   11篇
  1975年   12篇
  1974年   12篇
  1970年   6篇
排序方式: 共有1703条查询结果,搜索用时 343 毫秒
1.
Sonoelasticity imaging of prostate cancer: in vitro results   总被引:2,自引:0,他引:2  
  相似文献   
2.
Background: The American College of Cardiology (ACC)/American Heart Association (AHA) guidelines for Perioperative Cardiovascular Evaluation for Noncardiac Surgery recommend an algorithm for a stepwise approach to preoperative cardiac assessment in vascular surgery patients. The authors' main objective was to determine adherence to the ACC/AHA guidelines on perioperative care in daily clinical practice.

Methods: Between May and December 2004, data on 711 consecutive peripheral vascular surgery patients were collected from 11 hospitals in The Netherlands. This survey was conducted within the infrastructure of the Euro Heart Survey Programme. The authors retrospectively applied the ACC/AHA guideline algorithm to each patient in their data set and subsequently compared observed clinical practice data with these recommendations.

Results: Although 185 of the total 711 patients (26%) fulfilled the ACC/AHA guideline criteria to recommend preoperative noninvasive cardiac testing, clinicians had performed testing in only 38 of those cases (21%). Conversely, of the 526 patients for whom noninvasive testing was not recommended, guidelines were followed in 467 patients (89%). Overall, patients who had not been tested, irrespective of guideline recommendation, received less cardioprotective medications, whereas patients who underwent noninvasive testing were significantly more often treated with cardiovascular drugs ([beta]-blockers 43% vs. 77%, statins 52% vs. 83%, platelet inhibitors 80% vs. 85%, respectively; all P < 0.05). Moreover, the authors did not observe significant differences in cardiovascular medical therapy between patients with a normal test result and patients with an abnormal test result.  相似文献   

3.
4.
A rural hospital elective in a diploma nursing program is described. A need and opportunity for this unique practicum was identified in a Canadian province where one-third of the acute care beds are in hospitals of under 100 beds, located primarily in towns outside of metropolitan areas. The six week course offers students 35 hours of classroom content focusing on rural health care concepts plus a 150 hour practicum in one of three participating hospitals. The course is seen as unique in that it focuses on rural health care and is offered within the context of a diploma nursing program. Vive student outcomes are identified: awareness of the differences between rural and urban health care; integration of knowledge and experience from previous nursing courses as it relates to the rural context; increasing understanding of how rural population groups affect health care delivery; awareness of rural employment opportunities; and, preparation for the graduate role. A shared vision and collaborative effort on the part of the School of Nursing, the rural hospitals and the host communities has been necessary to establish and maintain such a course.  相似文献   
5.
55Co and 57Co were produced via (p, α) and (p, 2p) reactions, respectively, on highly enriched 58Ni. Thin deposits of 58Ni on Cu backing, obtained electrolytically, were irradiated using a slanting beam. The separation of radiocobalt and the recovery of the enriched target material were effected via anion-exchange chromatography.  相似文献   
6.
To develop guidelines for clinical magnetic resonance imaging of the liver, the authors undertook an animal study to investigate the effect of dose and pulse sequence on liver signal intensity in gadopentetate dimeglumine—enhanced echo-planar imaging. Serial imaging of the liver was performed in anesthetized rats after intravenous administration of five different doses (0.01, 0.05, 0.1, 0.2, and 0.5 mmol/kg) of contrast agent, with six different pulse sequences. The results show that gadopentetate dimeglumine—enhanced echo-planar images obtained during the perfusion phase can yield either positive (due to increased T1 relaxation rates) or negative (due to susceptibility-induced increased T2 relaxation rates) liver enhancement depending on choice of pulse sequence and dose. At the current clinically recommended dose of 0.1 mmol/kg, maximal liver signal enhancement was seen with a T1-weighted inversion-recovery sequence, while maximal liver signal diminution was seen with a T2*-weighted gradient-echo sequence. The authors conclude that gadopentetate dimeglumine—enhanced echo-planar imaging can provide T1, T2, and T2* contrast that may be exploited for both lesion detection and lesion characterization.  相似文献   
7.
Screening for early ovarian cancer   总被引:5,自引:0,他引:5  
Taylor  KJ; Schwartz  PE 《Radiology》1994,192(1):1
  相似文献   
8.
In patients with liver cirrhosis a transjugularly placed intrahepatic portocaval shunt (TIPS) is a non-surgical portosystemic device which aims to reduce portal venons pressure. In comparison with Doppler sonography, we evaluated in 28 patients the diagnostic impact of liver perfusion scintigraphy (with technetium-99m diethylene triamine penta-acetic acid) in the assessment of changes in the hepatic blood flow after TIPS shunting. The arterial and portal contributions to hepatic flow were calculated from the areas under the biphasic timeactivity curve. In the course of TIPS shunting, patency is threatened by reocclusion. Angiography is the gold standard for TIPS shunt reassessment. However, there is a need for a less invasive diagnostic procedure, such as scintigraphy or Doppler sonography, for the early detection of shunt insufficiency. Scintigraphy demonstrated that prior to TIPS shunting the portal venons contribution to hepatic perfusion was reduced to 29.2%, this reduction being due to portal hypertension. After TIPS placement a significant increase in portal venous perfusion was observed (38.2%;P<0.02). TIPS shunt occlusion was identified in patients by a significant reduction in the scintigraphically measured portal venons contribution to hepatic blood flow. Hepatic perfusion scintigraphy appears to be a valuable method to determine the immediate effect of TIPS on hepatic blood flow. Post-TIPS follow-up studies of hepatic haemodynamics by liver perfusion scintigraphy appear able to contribute to the detection of TIPS shunt occlusion before the clinical consequences of this complication have become apparent.  相似文献   
9.
New insights into potential mechanisms of ischemic preconditioning   总被引:6,自引:0,他引:6  
  相似文献   
10.
Junctional ectopic tachycardia is associated with a poor prognosis when it occurs in newborns and young infants. Like other automatic tachyarrhythmias, junctional ectopic tachycardia has been shown to be very resistant to medical treatment. Successful therapy with propafenone in a newborn with congenital junctional ectopic tachycardia is presented. Due to its high effectiveness, safety, and lack of side-effects, propafenone appears to be a valuable drug in the treatment of young patients with congenital junctional ectopic tachycardia.  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