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   939篇
  免费   24篇
  国内免费   7篇
耳鼻咽喉   2篇
儿科学   17篇
妇产科学   22篇
基础医学   107篇
口腔科学   1篇
临床医学   94篇
内科学   397篇
皮肤病学   11篇
神经病学   25篇
特种医学   8篇
外科学   81篇
综合类   10篇
一般理论   1篇
预防医学   80篇
眼科学   1篇
药学   39篇
中国医学   5篇
肿瘤学   69篇
  2022年   5篇
  2021年   20篇
  2020年   5篇
  2019年   12篇
  2018年   21篇
  2017年   6篇
  2016年   12篇
  2015年   11篇
  2014年   25篇
  2013年   37篇
  2012年   52篇
  2011年   53篇
  2010年   36篇
  2009年   38篇
  2008年   58篇
  2007年   87篇
  2006年   76篇
  2005年   71篇
  2004年   62篇
  2003年   57篇
  2002年   57篇
  2001年   5篇
  2000年   6篇
  1999年   13篇
  1998年   6篇
  1997年   9篇
  1996年   8篇
  1995年   8篇
  1993年   3篇
  1991年   9篇
  1990年   5篇
  1989年   4篇
  1988年   3篇
  1987年   7篇
  1986年   4篇
  1984年   6篇
  1983年   3篇
  1982年   7篇
  1981年   3篇
  1980年   8篇
  1978年   3篇
  1977年   3篇
  1976年   4篇
  1975年   6篇
  1974年   4篇
  1971年   2篇
  1969年   2篇
  1966年   2篇
  1965年   3篇
  1961年   2篇
排序方式: 共有970条查询结果,搜索用时 156 毫秒
101.
Aronow WS 《Geriatrics》2005,60(2):24, 26-24, 28
Cardiac resynchronization therapy (CRT) significantly improves functional status, exercise duration, left ventricular (LV) ejection fraction, death from progressive congestive heart failure (CHF), and hospitalization for CHF in patients with moderate-to-severe CHF, an abnormal LV ejection fraction, and a QRS duration on the electrocardiogram of 120 msec or more. In these patients, CRT reduces all-cause mortality, though not significantly. However, CRT plus. an implantable cardioverter-defibrillator (ICD) significantly reduces all-cause mortality. Compared with placebo, ICD therapy significantly reduced all-cause mortality by 33% in patients with class II or III CHF, an abnormal LV ejection fraction, and a QRS duration on the electrocardiogram of 120 msec or more.  相似文献   
102.
103.
We evaluated the relationship of S1 recorded by phonocardiography at the mitral area with motion of the mitral, tricuspid, and aortic valves, recorded by simultaneous echocardiography in 20 cardiac patients with a normal PR interval. The first major component of S1 coincided with mitral valve closure in 20 of 20 patients (100%) and also with tricuspid valve closure in 14 of 20 patients (70%). The second major component of S1 coincided with aortic valve opening in 20 of 20 patients and also with tricuspid valve closure in six of 20 patients (30%). We conclude that the first major component of S1 coincides with mitral valve closure in all patients but may also coincide with tricuspid valve closure in many patients, and the second major component of S1 coincides with aortic valve opening in all patients but may also coincide with tricuspid valve closure in some patients.  相似文献   
104.
Coronary risk factors should be modified in older persons after myocardial infarction (MI). Aspirin 160–325 mg daily and β blockers should be administered indefinitely. Anticoagulants should be administered post-MI to patients unable to tolerate daily aspirin, to those with persistent atrial fibrillation, and to those with left ventricular thrombus. Nitrates, along with βblockers, should be used to treat angina pectoris. Angiotensin-converting enzyme inhibitors should be administered after MI to patients who have congestive heart failure, an anterior MI, or a left ventricular ejection fraction of =40%. There are no class I indications for the use of calcium channel blockers after MI. Complex ventricular arrhythmias should be treated with βblockers. Persons with life-threatening ventricular tachycardia or ventricular fibrillation or who are at very high risk for sudden cardiac death after MI should receive an automatic implantable cardioverter-defibrillator. There are no class I indications for the use of hormonal therapy in postmenopausal women after MI. Indications for coronary revascularization after MI in older individuals are prolongation of life and relief of unacceptable symptoms despite optimal medical management.  相似文献   
105.
In this retrospective follow-up study, the authors examined the association between race and the receipt of cardiology care in 1062 Medicare beneficiaries 65 years of age and older who were hospitalized with heart failure. The primary outcome measure was receipt of care from a cardiologist (via admission or consultation). Using logistic regression analyses, crude and adjusted odds ratios (OR) and 95% confidence intervals (95%CI) of receipt of cardiology care were estimated for nonwhite versus white patients. Two hundred (19%) patients were nonwhites and 483 (46%) patients received care from cardiologists. Proportion of patients receiving cardiology care was lower among nonwhite patients (35% versus 48% among whites; P = 0.001), and nonwhite race was associated with a lower odds of receiving cardiology care (crude OR = 0.57; 95%CI = 0.42-0.79). After adjustment for various patient characteristics and process-of-care variables, the magnitude and precision of the association between nonwhite race and a lower odds of receiving care from a cardiologist remained unchanged (adjusted OR = 0.43; 95% CI = 0.30-0.62). These findings suggest that nonwhite elderly hospitalized heart failure patients are less likely to be cared for by cardiologists.  相似文献   
106.
Role of the 12-lead electrocardiogram in diagnosing pulmonary embolism   总被引:2,自引:0,他引:2  
We investigated the role of the standard 12-lead electrocardiogram (ECG) to improve the pretest probability of pulmonary embolism before performing computed tomographic (CT) pulmonary angiography. A retrospective chart analysis was performed on patients who underwent CT pulmonary angiography at a tertiary care hospital during a 30-month period. Comparison of 15 ECG parameters was made between those with CT pulmonary angiograms positive for pulmonary embolism and a matched control group with negative CT pulmonary angiograms. Data were analyzed by chi-squared tests and logistic regression. Sinus tachycardia (39% vs. 24%, P <0.01), an S1 Q3 T3 pattern (12% vs. 3%, P <0.01), atrial tachyarrhythmias (15% vs. 4%, P <0.005), a Q wave in lead III (40% vs. 26%, P <0.02), and a Q3 T3 pattern (8% vs. 1%, P <0.02) were the findings significantly associated with pulmonary embolism. We conclude that 1) standard 12-lead ECG findings can increase the pretest probability of pulmonary embolism before performing CT pulmonary angiography; and that 2) the ECG findings have relatively low likelihood ratios to have clinical use.  相似文献   
107.
Twenty-four patients with mitral valve prolapse underwent cardiac catheterization, exercise testing, and exercise 201thallium scintigraphy. Of 10 patients with coronary artery disease, six had abnormal scintigrams. Two of these six had exercise-induced reversible defects, two had defects that persisted during redistribution, and two had both reversible and persistent defects. Of 14 patients with normal coronary arteries, five had negative scintigrams. Of the remaining nine patients, two had exercise-induced defects, and seven (50%) had defects involving the inferior or posterior wall that persisted during redistribution. Possible mechanisms for this latter finding are discussed. In contrast to previous reports, exercise 201thallium scintigraphy was not entirely successful in identifying patients with coronary artery disease in our patients with mitral valve prolapse.  相似文献   
108.
By injecting a few cubic centimeters of saline into the coronary artery and using thermodilution principles, mean transit time (T(mn)) of the injectate can be calculated and is inversely proportional to coronary blood flow. Because microvascular resistance equals distal coronary pressure (P(d)) divided by myocardial flow, the product P(d). T(mn) provides an index of myocardial resistance (IMR). In this in vitro study in a physiologic model of the coronary circulation, we compared IMR to true myocardial resistance (TMR) at different degrees of myocardial resistance and at different degrees of epicardial stenosis. Absolute blood flow was varied from 42 to 203 ml/min and TMR varied from 0.39 to 1.63 dynes. sec/cm(5). Inverse mean transit time correlated well to absolute blood flow (R(2) = 0.93). Furthermore, an excellent correlation was found between IMR and TMR (R(2) = 0.94). IMR was independent on the severity of epicardial stenosis and thus specific for myocardial resistance. Thus, using one single guidewire, both fractional flow reserve and IMR can be measured simultaneously as indexes of epicardial and microvascular disease, respectively, enabling separate assessment of both coronary arterial and microvascular disease.  相似文献   
109.
Commentaries and debates at national medical meetings have fuelled the controversy about treatment of hypertension in patients aged 80 years and older. A double-blind, randomized, placebo-controlled trial was, therefore, indicated to settle the dispute about whether antihypertensive drug therapy is efficacious or harmful in these patients. Results from HYVET (Hypertension in the Very Elderly Trial) showed that, at 2-year follow-up, antihypertensive drug therapy with indapamide, plus perindopril if needed, reduced fatal or nonfatal stroke by 30%, fatal stroke by 39%, all-cause mortality by 21%, cardiovascular death by 23%, and heart failure by 64%. These results indicate that hypertensive patients aged 80 years and older should be treated with antihypertensive drugs.  相似文献   
110.

Objectives

To compare in a randomized, controlled trial the clinical effectiveness of care delivered by a clinical nurse specialist, inpatient team care, and day patient team care in patients with rheumatoid arthritis (RA) who have increasing functional limitations.

Methods

Between December 1996 and January 1999, 210 patients with RA were recruited in the outpatient clinic of the rheumatology department of 6 academic and nonacademic hospitals. Clinical assessments recorded on study entry and weeks 6, 12, 26, and 52 included the Health Assessment Questionnaire (HAQ) and the McMaster Toronto Arthritis Patient Preference Disability Questionnaire as primary outcome measures, and the RAND‐36 Item Health Survey, the Rheumatoid Arthritis Quality of Life questionnaire, the Health Utility Rating Scale, and the Disease Activity Score as secondary outcome measures. Patient satisfaction with care was measured on a visual analog scale in week 6 in all 3 groups and again in week 12 in the nurse specialist group.

Results

Within all 3 groups, functional status, quality of life, health utility, and disease activity improved significantly over time (P < 0.05). However, a comparison of clinical outcome among the 3 groups and a comparison between the nurse specialist group and the inpatient and day patient care groups together did not show any sustained significant differences. Subgroup analysis showed that age had a significant impact on differences between the 3 treatment groups with respect to functional outcome as measured with the HAQ (P < 0.001). With increasing age, the most favorable outcome shifted from care provided by a clinical nurse specialist and inpatient care to day patient care. Patients' satisfaction with care was significantly lower in the nurse specialist group than in the inpatient and day patient care groups (P < 0.001).

Conclusion

Care provided by a clinical nurse specialist appears to have a similar clinical outcome in comparison with inpatient and day patient team care. Although all patients were highly satisfied with multidisciplinary care, patients who received care provided by a clinical nurse specialist were slightly less satisfied than those who received inpatient or day patient team care. Age appeared to be the only factor related to differences in functional outcome between the 3 treatment groups. The choice of management strategy may, apart from age, further be dependent on the availability of facilities, the preferences of patients and health care providers, and economic considerations.
  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