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   691篇
  免费   26篇
耳鼻咽喉   1篇
儿科学   18篇
妇产科学   12篇
基础医学   74篇
口腔科学   19篇
临床医学   109篇
内科学   169篇
皮肤病学   76篇
神经病学   30篇
外科学   49篇
预防医学   71篇
眼科学   2篇
药学   81篇
肿瘤学   6篇
  2022年   10篇
  2021年   5篇
  2017年   7篇
  2016年   13篇
  2015年   10篇
  2014年   13篇
  2013年   30篇
  2012年   9篇
  2011年   7篇
  2010年   32篇
  2009年   37篇
  2007年   11篇
  2006年   8篇
  2004年   3篇
  2003年   5篇
  2002年   5篇
  2001年   7篇
  2000年   11篇
  1999年   13篇
  1998年   32篇
  1997年   36篇
  1996年   59篇
  1995年   47篇
  1994年   21篇
  1993年   25篇
  1992年   24篇
  1991年   15篇
  1990年   18篇
  1989年   14篇
  1988年   18篇
  1987年   10篇
  1986年   10篇
  1985年   9篇
  1984年   11篇
  1983年   7篇
  1982年   15篇
  1981年   17篇
  1980年   6篇
  1979年   9篇
  1978年   6篇
  1976年   5篇
  1975年   3篇
  1974年   3篇
  1971年   7篇
  1969年   5篇
  1958年   4篇
  1957年   9篇
  1956年   5篇
  1955年   4篇
  1954年   4篇
排序方式: 共有717条查询结果,搜索用时 15 毫秒
51.
Abstract:   Onychomycosis is widespread in the adult population, but considered to be rare in children. A number of studies in recent years show a rise in the prevalence of toenail onychomycosis in children. Of these, only a few were population-based. Here, we present a comprehensive cross-sectional population-based survey of toenail onychomycosis in primary school children in Israel. The survey included 1148 children, 598 boys, and 550 girls aged 5 to 14 from primary schools in the Jerusalem vicinity. Each child underwent a physical examination and completed a personal questionnaire, which provided background information of predisposing factors. The survey shows a prevalence of 0.87% of toenail onychomycosis. Although this figure is too small for statistical analysis, some important conclusions could be drawn: prevalence increased with age: boy/girl ratio was 2.2; the dominant etiologic agent was Trichophyton rubrum followed by Trichophyton mentagrophytes and Candida albicans . Infections were probably transferred from adults via the environment to children. Infected children came from different socio-economic backgrounds. This condition should be considered in the differential diagnosis of nail diseases in children.  相似文献   
52.
Testicular function was monitored in eight patients with low stage seminoma who were treated with radiotherapy following unilateral orchidectomy. The absorbed gonadal radiation dose ranged from 15 to 157.5 rad. At 10-24 months after radiotherapy, serum hormone levels, sperm analysis, sperm penetration into zona-free hamster ova (HOP-test) and lymphocyte chromosome abnormalities were evaluated. Two patients were azoospermic with elevated serum levels of LH and FSH. The remaining six patients had slightly decreased (n = 3) or normal (n = 3) seminal parameters. Their HOP rates were within the normal range. A low incidence of polyspermy (i.e. only one penetrating sperm per ovum) was found in the patients, suggesting low penetrability of motile sperm. A highly significant correlation was found between sperm count or sperm penetrability and time post-irradiation. The results indicate that restitution of testicular function is time-dependent.  相似文献   
53.
WNUK-WOJNAR, A.M., ET AL.: Predictors of Ventricular Tachycardia Inducibility in Programmed Electrical Stimulation and Effectiveness of Serial Drug Testing: Polish Multicenter Study. In 100 patients with IHD and complex ventricular arrhythmias, programmed electrical stimulation was performed using up to three extrastimuli at sinus rhythm, and paced 100, 120, and 140 beats/min delivered from the RV apex, outflow tract or the LV with ventricular mapping to evaluate late potentials (LP) in 41 patients. Sustained monomorphic VT (SMVT) was provoked in 91% of 42 patients with a history of VT/VF, p < 0.001, all five patients had SMVT in 24-hour ECG, p < 0.005, and 91% of 21 patients with LV dyskinesis, p < 0.01. After depolarizations were found in 62% of 21 patients with a history of VT, in 58% of 31 patients with inducible VT, p < 0.01 and in five of six patients with LV dyskinesis. In patients with inducible VT, LP had a higher amplitude (105 ± 35 vs 60 ± 47 µV) and were more delayed (202 ± 96 vs 133 ± 75 msec) than in noninducible patients. In 17 patients, serial drug testing was performed after oral administration using mexilitene, disopyramide, chinidine, propafenone, sotalol, and amiodarone. If one drug was tested, the therapy efficacy was 25% if two drugs-60%, and if three drugs-75%. In eight patients, VT was inducible in all tests, but in only one of these patients chronic antiarrhythmic therapy was not effective. We conclude that the most important predictors of VT inducibility are a history of VT or 24-hour ECG, and LV dyskinesis. Serial drug testing is efficient only when many drugs are tested, but even if VT is inducible, it does not exclude the possibility of a good clinical outcome in chronic therapy.  相似文献   
54.
The last two decades have provided clear evidence for the tight and casual relation existing between arrhythmic mortality and the autonomic nervous system, particularly with imbalances characterized by decreases in vagal and/or increases in sympathetic activity. A series of compelling experimental results has represented the driving force for the clinical evaluation of the potential prognostic value of baroreflex sensitivity (BBS), a measure that can provide information on the capability to augment vagal activity. This article reviews the methodology more commonly used to quantify the clinical evaluation of this parameter, and then focuses on the key clinical studies highlighting those performed in postmyocardial infarction patients. Among them the most informative is ATRAMI, a multicenter prospective study involving almost 1300 patients. The main conclusion is that both heart rate variability and BRS are strong and independent risk factors for post-infarction mortality, thus demonstrating the clinical usefulness of autonomic markers.  相似文献   
55.
Abstract. The endocrine-metabolic plasma pattern and the capacit of isolated perfused livers to produce triglcerides and ketone bodies have been studied in geneticall and diet-acquired obese rats (Zucker and Sprague-Dawle obese rats), and in control groups of the same strains.
An increased plasma insulin/glucagon molar ratio with hperinsulinaemia and hpoglucagonaemia was associated with hpertriglceridaemia, normal ketonaemia, elevated free fatt acids and normal or slight hperglcaemia in obese rats.
During oleate perfusion, the livers of Zucker and Sprague-Dawle obese rats showed an increase in triglceride output and liver triglceride content. The ketone bod output as well as the mitochondrial carnitine palmitol transferase activit were normal or slightl decreased.
In our rat population, a positive correlation between the insulin/glucagon molar ratio and triglceride output has been found.  相似文献   
56.
The Asymptomatic Patient with the Wolff-Parkinson-White Electrocardiogram   总被引:1,自引:0,他引:1  
Sudden death can be the first manifestation of the Wolff-Parkinson-White (WPW) syndrome. The underlying mechanism being atrial fibrillation with a very high ventricular rate, because of a short anterograde refractory period of the accessory atrioventricular pathway (AP), deteriorating into ventricular fibrillation. Information on the anterograde refractory period of the AP is therefore important to recognize asymptomatic people with the WPW ECG at risk for dying suddenly. Several noninvasive tests are available to identify the low risk patient. Decision making when to interrupt the AP in asymptomatic WPW patients not at low risk requires an invasive study to document the electrophysiological properties of the AP and to determine its exact location.  相似文献   
57.
MENOZZI, C., ET AL.: Intrapatient Comparison Between Chronic VVIR and DDD Pacing in Patients Affected by High Degree AV Block Without Heart Failure. In patients affected by high degree AV block without preexisting congestive heart failure there is no definite demonstration that DDD pacing gives real clinical advantages in respect to VVIR pacing. We performed an intrapatient, long-term study between the two pacing modes in 14 high degree AV block patients, using the Medtronic Synergyst 7027 dual chamber pacemaker, who could be programmed alternatively in DDD or VVIR mode. After a 4-week run-in period following the pacemaker implant, patients completed a randomized, double-blind, cross-over study to compare the effect of 6-week period VVIR and DDD pacing on symptoms and cardiovascular parameters. A semiquantitative score scale was used to quantify the symptoms of general well-being, palpitations, dizziness, pulsating sensation in the neck or abdomen, shortness of breath at rest and during effort, chest pain, and NYHA classification. The sum of symptom scores was 10.4 ± 6.7 in VVIR period and 4.6 ± 2.7 in DDD period (p < 0.001); five patients (36%) crossed over early from VVIR to DDD because of intolerable symptoms; overall, eight patients preferred the DDD mode and no one preferred the VVIR. Cardiac output at rest (echo-Doppler method) was 4.7 ± 1.4 versus 5.7 ± 1.6 liter/min (p < 0.01), body weight was 65.9 ± 6.6 versus 64.9 ± 6.1 kg (p < 0.02), atrial natriuretic peptide was 236 ± 112 versus 198 ± 110 pg/mL (p < 0.01), respectively, during VVIR and DDD modes. Effort tolerance was similar with the two modes of pacing (68 ± 15 vs 70 ± 18 watt/min). In conclusion, hemodynamic advantages of atrial synchronization reflect a better quality of life for the patients even if an individual variability exists.  相似文献   
58.
59.
The nature of the enhanced blood fibrinolytic activity which is known to occur during cardiopulmonary bypass is not understood. We show here that the cause is an increase in extrinsic (tissue-type) plasminogen activator. In six patients, the nature of the enhanced blood fibrinolytic activity that evolved during cardiopulmonary bypass was characterized by differential inhibition using the fibrin plate method and was shown to be C1-inactivator-resistant (extrinsic-activator activity). The C1-inactivator-resistant-activator activity was completely quenched by an antibody against extrinsic (tissue-type) plasminogen activator but not by antiurokinase, proving that the activity was due to the presence of extrinsic (tissue-type) plasminogen activator. The concentration of extrinsic (tissue-type) plasminogen activator increased during cardiopulmonary bypass and disappeared rapidly thereafter. Fibrinogen, plasminogen and alpha 2-antiplasmin were not consumed during cardiopulmonary bypass, while no increase or occasionally a moderate one in fibrinogen degradation products occurred. This is in accord with the property of extrinsic (tissue-type) plasminogen activator which activates plasminogen predominantly at sites where fibrin is present and not in the free circulation.  相似文献   
60.
The objective of this project was to develop computer-adaptive tests (CATs) using parent reports of physical function in children and adolescents with cerebral palsy (CP). The specific aims of this study were to (1) examine the psychometric properties of an item bank of lower-extremity and mobility skills for children with CP; (2) evaluate a CAT using this item bank; (3) examine the concurrent validity of the CAT with the Pediatric Outcomes Data Collection Instrument (PODCI) and the Functional Assessment Questionnaire (FAQ); and (4) establish the discriminant validity of simulated CATs with Gross Motor Function Classification System (GMFCS) levels and CP type (diplegia, hemiplegia, or quadriplegia). Parents ( n =190) of children and adolescents with spastic diplegic (48%), hemiplegic (22%), or quadriplegic (30%) CP consisting of 108 males and 82 females with a mean age of 10 years 7 months (SD 4y 1mo, range 2–21y) and in GMFCS levels I to V participated in item pool calibration and completed the PODCI and FAQ. Confirmatory factor analyses supported a unidimensional model for the 45 basic lower-extremity and mobility items. Simulated CATs of 5, 10, and 15 items demonstrated excellent accuracy (intraclass correlation coefficients [ICCs] >0.91) with the full item bank and had high correlations with PODCI transfers and mobility (ICC = 0.86) and FAQ scores (ICC = 0.77). All CATs discriminated among GMFCS levels and CP type. The lower-extremity and mobility skills item bank and simulated CATs demonstrated excellent performance over a wide span of ages and severity levels.  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