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   4036篇
  免费   82篇
  国内免费   26篇
耳鼻咽喉   176篇
儿科学   81篇
妇产科学   107篇
基础医学   559篇
口腔科学   80篇
临床医学   351篇
内科学   1087篇
皮肤病学   13篇
神经病学   262篇
特种医学   115篇
外科学   443篇
综合类   29篇
一般理论   3篇
预防医学   187篇
眼科学   79篇
药学   314篇
中国医学   2篇
肿瘤学   256篇
  2024年   21篇
  2023年   30篇
  2022年   157篇
  2021年   244篇
  2020年   70篇
  2019年   110篇
  2018年   139篇
  2017年   83篇
  2016年   103篇
  2015年   115篇
  2014年   164篇
  2013年   216篇
  2012年   318篇
  2011年   357篇
  2010年   171篇
  2009年   111篇
  2008年   236篇
  2007年   242篇
  2006年   269篇
  2005年   225篇
  2004年   226篇
  2003年   189篇
  2002年   138篇
  2001年   15篇
  2000年   11篇
  1999年   9篇
  1998年   16篇
  1997年   9篇
  1996年   13篇
  1995年   9篇
  1994年   5篇
  1993年   7篇
  1992年   6篇
  1991年   5篇
  1990年   14篇
  1989年   9篇
  1988年   8篇
  1987年   10篇
  1986年   4篇
  1985年   8篇
  1981年   4篇
  1980年   3篇
  1979年   7篇
  1978年   2篇
  1977年   5篇
  1975年   6篇
  1973年   2篇
  1971年   4篇
  1970年   5篇
  1969年   5篇
排序方式: 共有4144条查询结果,搜索用时 15 毫秒
71.
72.
BACKGROUND: Modern therapy of acute myocardial infarction (AMI) is aimed at rapid and persisting restoration of blood flow in an infarct-related artery (IRA). However, in some patients myocardial reperfusion is not achieved in spite of effective IRA recanalisation. Myocardial Blush Grade (MBG) is one of the angiographic markers useful for the detection of this phenomenon. AIM: To assess the prognostic value of MBG in patients with anterior AMI treated with primary angioplasty. METHODS: The study group consisted of 104 patients (74 males, 30 females, mean age 62+/-13 years) treated with primary angioplasty due to anterior ST-segment elevation AMI. MBG was assessed after the procedure. The mortality and major cardiovascular event (MACE) rates were analysed one and six months after AMI. RESULTS: Patients with preserved myocardial reperfusion following angioplasty (MBG 2-3, n=64 (61.5%)) had a trend towards lower one-month mortality and significantly reduced six-month mortality compared with 40 (38.5%) patients with an impaired (MBG 0-1) myocardial reperfusion (3% vs 12.5%, NS; and 6.25% vs 20%, p<0.05, respectively). The rate of MACE was significantly lower in patients with rather than without reperfusion both after one and six months of follow-up (9.4% vs 27.5%, p=0.027 and 12.5% vs 42.5%, p<0.001, respectively). Compared with patients with a high MBG score, patients with altered reperfusion more frequently had diabetes (30% vs 12.5%, p=0.04), hypertension (67.5% vs 45%, p=0.043), longer time from the onset of symptoms to balloon inflation (355.9+/-199 min vs 215.5+/-113 min, p<0.001) and lower left ventricular ejection fraction, measured 3 days after AMI (43.3%+/-8 vs 47.4%+/-9, p=0.02). CONCLUSIONS: MBG has a significant prognostic value in patients with anterior AMI treated with primary angioplasty. Diabetes, hypertension and long delay of treatment are associated with the impairment of myocardial reperfusion.  相似文献   
73.
The objective of the study was to assess the severity of depression and to assess the level of self-sufficiency of patients with Alzheimer's disease, with particular emphasis on the place of residence and level of education. The study covered 90 people diagnosed with Alzheimer's disease. All respondents were persons over 65?years of age and residents of cities with a population over one-hundred thousand. The research method based on this work is the author's own questionnaire, the Zung Self-Rating Depression Scale (ZSDS) about depression and the Karnofsky Performance Scale Index (KPSI) for assessment of a patient's self-sufficiency. Regardless of residence, patients with Alzheimer's disease displayed signs of mild or moderate depression (100% in social welfare homes and hospital patients and 60% in those with caregivers at home). Patients with Alzheimer's disease have an unsatisfactory salary in social-economic terms. In those with Alzheimer's disease, quality of life is best for those in family homes under the care of their immediate family. People with a vocational education were the largest group of people diagnosed with Alzheimer's. Patients at home and in the hospital had a higher level of physical activity, but most patients in the hospital needed regular medical care, as did patients in social welfare homes.  相似文献   
74.
BACKGROUND: Cardioversion of atrial fibrillation (AF) carries the risk of thromboembolic complications and, therefore, anticoagulation therapy is routinely administered before and after this procedure. In patients with permanent AF who undergo implantation of cardioverter-defibrillator (ICD), anticoagulants are usually withdrawn during the perioperative period. However, in some patients sinus rhythm may be restored during defibrillation threshold (DFT) testing which potentially may increase the risk of thromboembolic complications. AIM: To assess the frequency of sinus rhythm restoration during ICD implantation in patients with permanent AF and the rate of both thromboembolic events and local bleeding complications which may occur due to temporary withdrawal of anticoagulation therapy and its re-initiation early after the procedure. METHODS: Permanent AF was present in 23 (12%) of 193 patients selected for ICD implantation. All patients received prolonged oral anticoagulation according to the generally accepted standards. Anticoagulation therapy was stopped few days before the procedure and replaced by low molecular weight heparin which was administered up to 24 hours before ICD implantation and re-initiated 12-24 hours afterwards. RESULTS: During DFT testing sinus rhythm was restored in 5 (21.7%) patients with AF. Clinical and DFT characteristics were similar in those who were converted to sinus rhythm and those who remained in AF. No thromboembolic events were noted in either group. Local haematoma at the site of ICD implantation occurred in two (8%) patients. CONCLUSIONS: Sinus rhythm was restored in 21.7% of patients with permanent AF who underwent ICD implantation. Temporary withdrawal of anticoagulation therapy did not increase the risk of thromboembolic complications, however, its early re-initiation after implantation resulted in an increase in local bleeding complication rate.  相似文献   
75.
BACKGROUND AND AIMS OF THE STUDY: The outcome of percutaneous balloon mitral commissurotomy (BMC) has been reported as poor in patients with prior surgical commissurotomy. The study aim was to evaluate immediate and long-term follow up results of BMC in patients with restenosis after surgical commissurotomy compared to patients with 'de-novo' mitral stenosis. METHODS: Between October 1988 and September 1999, a total of 1,027 patients underwent BMC. Of these patients, 169 (16.5%) were examined at 17+/-7 years (range: 2-33 years) after surgical commissurotomy (group 1), and 858 (83.5%) had de-novo mitral stenosis (group 2). RESULTS: Group 1 patients were older than group 2 patients (49.4+/-9.3 versus 47.3+/-9.6 years; p <0.05), and atrial fibrillation was seen more often in group 1 (53.9% versus 32.4%; p <0.005). Before BMC, mitral valve area (MVA) was similar in both groups (1.18+/-0.27 and 1.15+/-0.26 cm2 in groups 1 and 2 respectively; p = NS); following BMC, MVA was 1.82+/-0.3 and 1.93+/-0.40 cm2 respectively (p <0.05). Four patients (2.4%) from group 1, and 24 (2.8%) from group 2 required mitral valve replacement due to severe regurgitation (p = NS). Annual clinical and echocardiographic evaluation was completed for 950 patients (mean follow up 56.2+/-31.1 months (range: 12-132 months). Cardiac events defined as death, valve surgery or repeat BMC occurred in 16.0% of patients in group 1, and in 9.6% of those in group 2. At follow up of three, five and 10 years, actuarial event-free survival was 85.7+/-2.9%, 79.8+/-3.8% and 65.2+/-7.5% respectively in group 1, and 93.4+/-0.9%, 90.1+/-1.1% and 72.7+/-3.9% respectively in group 2 (log rank test, p = 0.02). Multivariate analysis showed MVA <1.5 cm2 after BMC, mitral regurgitation grade >2/4, Wilkins score >8, and mean transmitral gradient and left atrial mean pressure post BMC to be independent predictors of an adverse event occurring during follow up. CONCLUSION: BMC in patients with restenosis after surgical commissurotomy is an effective method of treatment, and may help to avoid valve surgery in most patients.  相似文献   
76.
BACKGROUND: Heavy alcohol drinking is associated with a dose-dependent increase in blood pressure, but data on the relation between alcohol consumption and mortality in hypertensive patients are sparse. OBJECTIVE: To assess the relation between light to moderate alcohol consumption and total mortality from cardiovascular disease (CVD) among men with hypertension. PARTICIPANTS AND DESIGN: From the Physicians' Health Study enrollment cohort of 88,882 men who provided self-reported information on alcohol intake, we identified a group of 14,125 men with a history of current or past treatment for hypertension who were free of myocardial infarction, stroke, cancer, or liver disease at baseline.Main Outcome Measure Comparison of total and CVD mortality among men with hypertension who had reported to be either nondrinkers or rare drinkers, or light to moderate drinkers. RESULTS: During 75,710 person-years of follow-up, there were 1018 deaths, including 579 from CVD. Compared with individuals who rarely or never drank alcoholic beverages, those who reported monthly, weekly, and daily alcohol consumption, respectively, had multivariate adjusted relative risks (RRs) for CVD mortality of 0.83 (95% confidence interval [CI], 0.62-1.13), 0.61 (CI, 0.49-0.77), and 0.56 (CI, 0.44-0.71) (P<.001 for linear trend). In the same groups, RRs for total mortality were respectively 0.86 (CI, 0.67-1.10), 0.72 (CI, 0.60-0.86), and 0.73 (CI, 0.61-0.87) (P<.001 for linear trend). Among men with a systolic blood pressure of 140 mm Hg or higher or a diastolic blood pressure of 90 mm Hg or higher, the RRs for CVD mortality were, respectively, 1.00 (referent), 0.82 (CI, 0.56-1.21), 0.64 (CI, 0.48-0.85), and 0.56 (CI, 0.42-0.75) (P<.001 for linear trend). On the other hand, we found no significant association between moderate alcohol consumption and cancer mortality (P =.8 for linear trend). CONCLUSION: These results, which require confirmation in other large-scale studies, suggest that light to moderate alcohol consumption is associated with a reduction in risk of total and CVD mortality in hypertensive men.  相似文献   
77.
BACKGROUND: Acute myocardial infarction (AMI) is one of the main causes of death in the elderly, however, the optimal therapy of AMI in this age-group has not yet been established. AIM: To compare the early outcome of patients with AMI aged > or =75 years who underwent primary percutaneous coronary interventions (PCI) or were treated conservatively. METHODS: In-hospital outcome of 180 patients aged > or =75 years, hospitalised due to AMI, was retrospectively analysed. Ninety two consecutive patients, admitted with AMI between May 2001 and October 2002, underwent primary PCI whereas 88 patients, treated for AMI between 1993 and 2002, received standard pharmacological therapy without thrombolysis. CONCLUSIONS: Primary PCI in the elderly with AMI is significantly more effective than conservative therapy, except with patients with cardiogenic shock in whom mortality is similar regardless of the therapy used.  相似文献   
78.
The aim of this study was to evaluate the influence of blood pressure variability and circadian rhythm on left ventricular mass and urinary albumin excretion rate (UAE) in patients with essential hypertension. 82 untreated patients (35 women and 47 men; mean age 41.1 +/- 13.7) were recruited to this study. Mean office blood pressure at entry was 152/97 mmHg. Ambulatory blood pressure monitoring (ABPM) was performed using an Medilog ABP recorder (Oxford). Blood pressure variability was estimated as the standard deviation (SD) of systolic and diastolic ambulatory blood pressure. Urinary albumin excretion (UAE) was estimated by the radioimmunoassay during two separate days. Echocardiography was used to measure left ventricular mass and left ventricular mass index (LVMI). The median urinary albumin excretion for the whole group was 8.2 mg/day; in 18 patients (21.9%) microalbuminuria was present. Left ventricular mass index in a whole group was 109.1 g/m2; in 23 subjects (28.0%) left ventricular hypertrophy (LVH) was found. Patients with microalbuminuria as well as with left ventricular hypertrophy had higher office and 24 hour ambulatory systolic and diastolic blood pressure and higher systolic blood pressure variability. During ABPM 18 patients with absent nocturnal fall in blood pressure (non-dippers) were found; they did not display more frequent prevalence of target organ damage. Increased 24-hour blood pressure variability present in hypertensive subjects with both microalbuminuria and left ventricular hypertrophy may suggest that this phenomenon plays role in development of target organ damage.  相似文献   
79.
Sulfonylureas are used in treatment of diabetes. Resistance to these derivatives is a therapeutical problem. Sulfonylureas act through sulfonylurea receptor 1 (SUR1) in the beta cell. SUR1 also enhances a physiological secretion of insulin induced by an increase of glucose concentration. It may be expected that polymorphism of SUR1 gene can lead to beta cell dysfunction and resistance to sulfonylureas. The aim of this study was to examine the frequency of polymorphism in exon 22 of SUR1 gene and its correlation with type 2 diabetes mellitus and sulfonylurea treatment failure. The group consisted of 42 patients with type 2 diabetes. The controls were 46 persons with proper glucose tolerance. Polymorphism was found in 5 patients and in 1 control person. Neither statistically significant difference of polymorphism frequency nor correlation between polymorphism and sulfonylurea failure was found due to a low number of cases. Polymorphism of exon 22 of SUR1 gene appeared more frequent in diabetic than in non-diabetic subjects but this was statistically not significant.  相似文献   
80.
Aim of this prospective study was to assess quality of life (QoL), left ventricular (LV) function and exercise performance in two groups of patients (pts) with atrial fibrillation (Af) treated with: radiofrequency catheter ablation (RFA) and antiarrhythmic drugs (AA). Between 1996 and 2000 - 74 patients, 28 women, with drug refractory Af were enrolled by clinical indications for two modes of therapy: RFA and AA. RFA group consisted of 38 pts, 63.7 +/- 11.5 years old: 28 pts with RF AV Node ablation and pacemaker implantation (PI) and 10 pts with AV Node modification or right atrial isthmus RF ablation due to Af conversion to atrial flutter (Aflu) during medical therapy. AA group consisted of 36 pts, aged 59.7 +/- 13.8 years. Patients from RFA group suffered significantly more serious diseases than pts from AA group. No significant (sign.) differences between two groups were found in age, gender, arrhythmia history and number of AA taken. Pts were analyzed before entry, after 3 and 12 months of follow-up (3 mo. FU, 12 mo. FU) with following indices: LV function (Echo: EF & FS), exercise performance (treadmill test), QoL questionnaires, number of hospital admissions connected to arrhythmia or procedures (RFA & PI), number of AA drugs taken in RFA group. RFA group: Two deaths occurred due to end stage respiratory insufficiency (COPD), one pt required reposition of pacemaker lead. AA group: 3 pts required RFA due to uncontrolled Af/Aflu (AV Node ablation with PI - 1 pt, right atrial isthmus ablation - 2 pts). Analysis of two patients groups: LV function: Sign. improvement (EF & FS) in both groups in 12 mo. FU; Exercise performance: no sign. changes in 3 and 12 mo. FU. QoL: Arrhythmia scale: 3 mo. FU sign. reduction in both groups; 12 mo. FU reduction in RFA group only; Anxiety scale: 3 and 12 mo. FU sign. reduction of anxiety level in RFA group; Exercise and activity scales: 3 and 12 mo. FU sign. improvement in RFA group. During 3 and 12 mo. FU sign. less pts from RFA group required hospital admission versus pts from AA group. Sign. reduction in AA was noted in RFA group. Patients with symptomatic Af treated with RFA benefit from this kind of therapy more than patients treated with AA. Quality of life improvement visible in short term observation in patients from RFA group is still present after one year observation. Improvement in LV function is observed after one year in both groups of pts with Af.  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