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   628篇
  免费   34篇
耳鼻咽喉   7篇
儿科学   17篇
妇产科学   24篇
基础医学   63篇
口腔科学   9篇
临床医学   44篇
内科学   209篇
皮肤病学   18篇
神经病学   104篇
特种医学   23篇
外科学   52篇
综合类   1篇
预防医学   40篇
眼科学   1篇
药学   11篇
中国医学   1篇
肿瘤学   38篇
  2023年   3篇
  2021年   4篇
  2020年   3篇
  2019年   12篇
  2018年   15篇
  2017年   7篇
  2016年   6篇
  2015年   11篇
  2014年   19篇
  2013年   28篇
  2012年   29篇
  2011年   27篇
  2010年   16篇
  2009年   15篇
  2008年   21篇
  2007年   33篇
  2006年   35篇
  2005年   29篇
  2004年   30篇
  2003年   25篇
  2002年   25篇
  2001年   37篇
  2000年   29篇
  1999年   19篇
  1998年   12篇
  1997年   4篇
  1996年   4篇
  1995年   4篇
  1994年   4篇
  1993年   3篇
  1992年   8篇
  1991年   13篇
  1990年   9篇
  1989年   9篇
  1988年   7篇
  1987年   9篇
  1986年   7篇
  1985年   10篇
  1984年   9篇
  1982年   7篇
  1981年   4篇
  1980年   8篇
  1979年   3篇
  1978年   12篇
  1977年   5篇
  1976年   11篇
  1975年   3篇
  1974年   7篇
  1968年   2篇
  1966年   2篇
排序方式: 共有662条查询结果,搜索用时 0 毫秒
1.
Dipyridamole has been reported to inhibit platelet aggregation in citrate anticoagulated whole blood (WB). However, citrate may alter the response of platelets and/or the effect of antiplatelet drugs. The present study evaluates the "ex vivo" effect of dipyridamole, two hours after a single dose (3 mg/Kg) in 25 normal subjects in non-anticoagulated (native) WB and in WB anticoagulated with citrate or hirudin. We have used the BASIC anticoagulated with citrate or hirudin. We have used the BASIC wave as analytical method, which can evaluate the early steps of platelet activation with collagen in less than 1 min after venoclysis, thus allowing the study in native WB. The results show that dipyridamole significantly inhibits (p less than 0.001) platelet activation to collagen in citrated WB (66%) while the drug's effect is much lower (21%) and non-significant if evaluated in native or hirudine anticoagulated WB. These results suggest that citrate or low calcium concentration amplify the drug's platelet inhibitory action in WB and, therefore, the laboratory results may overestimate the drug's effect "in vivo".  相似文献   
2.
Blood rheological properties were studied in 21 patients suffering from essential hypertension (EHT), degree I-II according to WHO criteria. These patients were diagnosed "de novo". The whole blood filterability (WBF), blood viscosity (BV) at 230 s-1 and 23 s-1, red cell deformability (FI), erythrocyte aggregation in autologous (MEA) and normal plasma (MEAc), fibrinogen (Fbg) and hematocrit (Ht) have been evaluated. In the hypertensive patients we have found decreased WBF, greater BV and FI in comparison with the control group (p less than 0.001). Likewise, MEA and Fbg were increased, though the differences were less significant (p less than 0.01). The evaluation of Ht did not show any differences between the two groups. The results suggest that in the newly diagnosed EHT, clear hemorheological alterations occur, both in plasma and in the erythrocytes, which could play a role in the pathogenesis of the aforementioned disease.  相似文献   
3.
The genetic polymorphism of Mycobacterium tuberculosis strains isolated in Seville, Spain, was studied by using computer-assisted analysis of the IS6110 fingerprint in order to determine the current situation and to evaluate the human-to-human transmission of this pathogen. One hundred seventy-six isolates from 175 patients among the 205 patients diagnosed with tuberculosis (TB) during a 3-year period (1993 to 1995) were cultured and analyzed. One hundred nine patients (62%) were infected with genetically different isolates, and 67 isolates (38%) were grouped into 19 clusters. These results demonstrate that the level of clustering of strains in Seville is intermediate between those in developed and developing countries. Epidemiological relatedness was shown for isolates from only 10 of these clusters. Active and high transmission rates exist in children and in human immunodeficiency virus (HIV)-infected adults, while in non-HIV-infected adults this transmission rate is moderate. Although transmission from children to adults is uncommon, the probability of transmission from HIV-infected patients to young adults not infected with HIV may be higher. On the basis of these observations, we predict a constant rise in the rate of TB transmission among HIV-infected patients and probably in young adult patients not infected with HIV if measures for the effective prevention of TB among the HIV-infected population are not implemented.  相似文献   
4.
The purpose of these experiments was to study the incidence of stress ulcers in restrained rats and to correlate it with hypothalamic and adrenal cortical and medullary activity, with and without vagotomy. A total of 217 adult rats were used, grouped into 56 sets, and distributed at random in 5 experimental groups. Restraint was followed by a 79% incidence of ulceration in the glandular portion of the gastric mucosa. Vagotomy made these worse (p<0.01). Hypothalamic levels of catecholamines and serotonin showed no significant changes. Urinary measurements revealed decreased excretion of 17-ketosteroids (p<0.001), increased excretion of uropepsinogen (p<0.01), and no significant changes in vanillylmandelic acid among the rats submitted to immobilization. In the adrenal glands of stressed animals, there was a decreased level of catecholamines (p<0.01) and no significant changes in corticosteroid content (17-ketosteroids). These results suggest that hypothalamic stimulation and the participation of the adrenal glands are not essential factors in the pathogenesis of restraint-induced experimental stress ulcer.  相似文献   
5.
We explored the effect of fibrin glue injection at the site of dural puncture on cerebrospinal fluid (CSF) leakage in a swine model. Pigs were subjected to a lumbar dural CSF puncture in the sitting position with a 17-gauge Tuohy needle. Fibrin glue 1.4 mL was injected through the same needle into the epidural space. Evans blue dye was infused through the cisterna magna 15 min later, and the appearance of dyed CSF through the skin puncture and along the needle trajectory to the dura was inspected and categorized. In seven of eight animals, the CSF leak was sealed with fibrin glue. Control animals were injected with 1.4 mL saline. A sham operation group of animals underwent cisternal dye infusion without a lumbar puncture. CSF pressure at the cisterna magna was recorded throughout the procedure. No significant differences in the leakage indicators were found between the fibrin glue-injected and sham-operated group, whereas both groups showed significant differences with respect to the control group. The fibrin glue seal was effective against CSF pressures of 24.5 [17-31] cm H(2)O. We conclude that percutaneously injected fibrin glue is effective in stopping CSF leaks after dural puncture in this animal model. IMPLICATIONS: In this swine study, we repaired a cerebrospinal fluid leak after a dural puncture by percutaneously injecting tissue adhesive. The technique of percutaneous injection of fibrin glue seems promising for the prophylaxis of headache associated with cerebrospinal fluid leakage, and may be an alternative to an epidural blood patch.  相似文献   
6.
7.
8.
Coupled with the growth of the older population, an increase in the prevalence of overweight and obesity in this age group has occurred in the last decades. The main aims of the present study were (i) to provide an updated prevalence of overweight and obesity in a representative sample of the Spanish elderly population; (ii) to calculate the prevalence of sarcopenic obesity (SO) and (iii) to analyse the relationships between adiposity measurements and lifestyle. A cross‐sectional study was carried out in a sample of 3136 persons representative of the non‐institutionalized population ≥65 years of age. Anthropometric measurements were obtained using standardized techniques and equipment. Overall, 84% of the population can be categorized as overweight and/or obese. The present study indicates that 67% of the Spanish elderly population has an increased percentage of fat mass and more than 56% suffer from central obesity. Moreover, SO is present in 15% of the Spanish elderly population. Finally, a strong relationship between both physically active and sedentary lifestyles and the level of adiposity was found. Prevalence of overweight and obesity among elderly people in Spain is very high and is still increasing. Lifestyle seems to be a determinant factor in the development of obesity among elderly people.  相似文献   
9.
Heart disease is the leading cause of non-cancer death in childhood cancer survivors. to determine the prevalence of subclinical cardiac dysfunction using speckle tracking and compare its results with those obtained by classical methods of assessing left ventricular function and its relationship with different factors to identify the population at higher risk. Echocardiographic assessment of left ventricular function included ejection fraction, tissue Doppler, longitudinal/circumferential strains and biochemical parameters (troponin-T and Pro-BNP) in a cohort of 57 survivors of childhood acute leukaemia with at least 10 years since diagnosis. Ventricular dysfunction was found in 5.2% of patients in M-mode (ejection fraction—EF?<?53% with a reduction in the EF?≥?10%) and in 7% of patients with Simpson’s method, compared with 21.05 and 8.8% with suboptimal global longitudinal strain (GLS) and global circumferential strain, respectively. The GLS alteration was significantly correlated with lower values of left ventricular systolic function and was associated with high tumour risk (odds ratio [OR] 13.8), cumulative doses of anthracyclines?≥?250 mg/m2 (OR 7.6) and radiotherapy (OR 7.19). Biomarkers were not useful for the diagnosis of subclinical cardiomyopathy. Good reproducibility was obtained, with an intraobserver correlation of 93.6% and an interobserver correlation of 89.2% in the GLS. The alteration of the GLS was more prevalent than the alteration in the EF and was associated with the treatment received and high tumour risk. strain imaging seems to be a powerful tool to identify an increased number of survivor with an early myocardial injury.  相似文献   
10.
INTRODUCTION AND OBJECTIVES: This cross-sectional study examined the overall clinical characteristics and management of 1252 outpatients with heart failure in 3 countries (Spain, France and Germany). MATERIAL AND METHOD: A standardized questionnaire was used to record demographic, diagnostic, clinical and treatment data for all patients seen on one day (26 April 2001) by 465 outpatient cardiologists. RESULTS: Men accounted for 62.1% of the patients in the population, and mean age of the patients was 68.3 years. In the twelve months prior to the study 78% of the patients consulted their physician at least once because of heart failure, and 36.2% had hospital admissions. Differences between the three countries were observed in reported causes of heart failure (alone or in combination) such as ischemic heart disease (France 40.7%, Germany 41.3%, Spain 26%, P<.0001) and hypertension (France 10.7%, Germany 16.7%, Spain 43.6%, P<.0001). How-ever the proportion of patients with prior myocardial infarction was very similar (France 63.7%, Germany 69.5%, Spain 65%, P=NS). Diuretics were not prescribed in 19.7% of the patients, ACE inhibitors were not prescribed in 27.9%, and beta blockers were not prescribed in 52.3%. CONCLUSIONS: The study provides further information on the consumption of large amounts of medical resources because of heart failure. The reported etiologies differed between countries. However, the proportion of patients with prior myocardial infarction was very similar. Treatment with ACE inhibitors and beta blockers was slightly more common than previously reported, although beta blockers continue to be underused.  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