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   2267篇
  免费   139篇
  国内免费   15篇
耳鼻咽喉   3篇
儿科学   14篇
妇产科学   10篇
基础医学   220篇
口腔科学   17篇
临床医学   169篇
内科学   816篇
皮肤病学   21篇
神经病学   272篇
特种医学   73篇
外科学   327篇
综合类   6篇
预防医学   56篇
眼科学   18篇
药学   182篇
中国医学   4篇
肿瘤学   213篇
  2023年   11篇
  2022年   21篇
  2021年   55篇
  2020年   35篇
  2019年   41篇
  2018年   45篇
  2017年   24篇
  2016年   48篇
  2015年   57篇
  2014年   65篇
  2013年   69篇
  2012年   137篇
  2011年   175篇
  2010年   76篇
  2009年   72篇
  2008年   119篇
  2007年   160篇
  2006年   127篇
  2005年   152篇
  2004年   148篇
  2003年   124篇
  2002年   124篇
  2001年   68篇
  2000年   72篇
  1999年   63篇
  1998年   21篇
  1997年   18篇
  1996年   20篇
  1995年   22篇
  1994年   16篇
  1993年   13篇
  1992年   19篇
  1991年   27篇
  1990年   27篇
  1989年   34篇
  1988年   14篇
  1987年   11篇
  1986年   12篇
  1985年   8篇
  1984年   9篇
  1983年   7篇
  1979年   4篇
  1978年   11篇
  1977年   4篇
  1976年   2篇
  1975年   3篇
  1974年   6篇
  1973年   6篇
  1972年   4篇
  1971年   10篇
排序方式: 共有2421条查询结果,搜索用时 0 毫秒
1.
OBJECTIVE: To verify the feasibility and compare the results of thoracoscopic sympathectomy under local anaesthesia (LA) and spontaneous breathing vs. general anaesthesia (GA) with one-lung ventilation. METHODS: Two groups of consecutive patients underwent one stage bilateral T2-T3 thoracoscopic sympathectomy under LA (n=15) and GA (n=30) by the same surgical team for treatment of primary palmar hyperhidrosis. The groups were homogeneous for relevant demographic, physiological and clinical data, including pulmonary function. In both groups, patient's satisfaction was evaluated 24h after surgery by a simple interview and scored into five grades (1=very poor to 5=excellent), while quality of life (QOL) was evaluated by SF-36 and Nottingham's Health Profile questionnaires before and 6 months after surgery. A cost comparison between groups concerning devices, drugs, global in operating room time, medical personnel and hospital stay was also carried out. RESULTS: No operative mortality was recorded. The overall in operating room time for the whole bilateral procedure under LA was 63.55+/-10.58 vs. 86.05+/-5.75 under GA (P<0.01) and temperature increased in all patients from a baseline of 25.42+/-0.56 up to 32.15+/-0.84 degrees C. All patients undergone LA were discharged the same day after a chest roentgenogram and a short stay in the outpatient clinic. Among them three patients (20%) experienced a minimal (<30%) pneumothorax that required no treatment, while five (33.3%) had a trunk compensatory sweating that spontaneously resolved on the long run. Patients undergoing GA were discharged after a mean stay of 1.38+/-0.6 days. Among these, eight (26.6%) had prolonged trunk compensatory sweating that did not persist longer than 3 months. At a follow-up of 7.16+/-2.97 months, QOL was significantly improved with no difference between groups. The overall rate of satisfaction was greater in the LA group (P<0.05). CONCLUSIONS: In our study, awake one stage bilateral thoracoscopic sympathectomy for palmar hyperhidrosis could be safely and effectively performed as an outpatient procedure in patients refusing GA. Postoperative quality of life was equal to that in patients undergone the same procedure under GA, while patient satisfaction was better and cost were significantly reduced.  相似文献   
2.
Comparison of loop diuretics in patients with chronic renal insufficiency   总被引:1,自引:0,他引:1  
Furosemide and bumetanide share a number of characteristics including reduced natriuretic effects in azotemic patients. It has been presumed that this condition affects each drug equally. Previous studies, however, suggest dissimilar pathways of delivery to their sites of action. Though not rigorously tested, this potential disparity might cause them to differ when used in azotemia. We, therefore, assessed the pharmacokinetic and pharmacodynamic characteristics of intravenously administered furosemide and bumetanide in ten adult patients with stable, chronic renal insufficiency (mean creatinine clearance = 14.1 +/- 2.0 ml/min/1.73 m2) in a randomized, cross-over study during controlled sodium intake. Our goals were to assess differences in diuretic effectiveness and in so doing to determine the dose required to produce a maximal response. The mean diuretic doses of 172 and 4.3 mg for furosemide and bumetanide, respectively (ratio = 40:1) were sufficient to produce a maximum response. Despite similarities in maximal fractional excretion of sodium (18.2 +/- 2.6% with furosemide vs. 19.4 +/- 4.5% with bumetanide, P = 0.687) demonstrating an equal tubular responsiveness to both drugs, overall response as quantified by cumulative natriuresis in the initial eight hour period was 52% greater with furosemide (108 +/- 17 vs. 71 +/- 7 mEq; P = 0.042). The difference in total excreted sodium was accounted for by a preserved nonrenal clearance of bumetanide (113 +/- 12 compared to 53 +/- 5 ml/min for furosemide, P = 0.001) which resulted in relatively less bumetanide in serum available to be delivered into the urine.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
3.
We report the clinical, SPET, immunohistochemical and DNA features of an early-onset familial Alzheimer's disease (FAD) in an Argentine pedigree of South American indian ethnic background. Pedigree spans 5 generations comprising more than 110 biological relatives. Clinical data supported the diagnosis of early onset FAD (mean age at onset 38.9 years) in 10 family members, including 3 with pathological confirmation (mean age at death 48.5). The pattern of transmission suggested autosomal dominant inheritance. Prominent features were mood changes, early language impairment, myoclonus, seizures and cerebellar signs. SPET displayed bilateral frontal, temporo-parietal and cerebellar hypoperfusion in early stages and in an asymptomatic member at risk, suggesting that SPET may have predictive value in this family. Immunohistochemistry showed β amyloid deposits within neuritic plaques and vessel walls and no anti-PrP immunoreactivity. DNA analysis showed no abnormalities in the β amyloid precursor protein gene. The identification of additional genetic defects in well characterized independent FAD pedigrees will contribute to the understanding of the pathogenesis of Alzheimer's disease.  相似文献   
4.
5.
6.
The influence of a sodium citrate/citric acid mixture on the gastrointestinal (GI) absorption of aluminum (Al) from an Al(OH)3 preparation was evaluated in six stable maintenance hemodialysis patients. Plasma Al concentrations were determined serially after each of the following treatment sequences (I) Al(OH)3; (II) Al(OH)3 + sodium citrate/citric acid; (III) sodium citrate/citric acid; (IV) Al(OH)3 + NaHCO3. AUC0-8 for plasma Al from 0 to 8 hours was significantly greater (p less than 0.05) for Al(OH)3 + sodium citrate/citric acid (73 +/- 23 micrograms.hr/l; mean +/- SEM) than Al(OH)3 (16 +/- 30 micrograms.hr/l); sodium citrate/citric acid (-27 +/- 14 micrograms.hr/l); or Al(OH)3 + NaHCO3 (6 +/- 22 micrograms.hr/l). The 24 hour Al level remained above baseline (p less than 0.03) following Al(OH)3 + sodium citrate/citric acid (31 +/- 12 (pre) vs 54 +/- 14 micrograms/l (post), in contradistinction to study limb: l (34 +/- 14 vs 30 +/- 12 micrograms/l); III (79 +/- 40 vs 65 +/- 35 micrograms/l); and IV (71 +/- 37 vs 66 +/- 42 micrograms/l). We conclude that the GI absorption of Al from Al(OH)3 is enhanced by citrate in patients undergoing hemodialysis and that elevations of plasma Al persist longer. The concomitant administration of citrate and Al-containing phosphate (PO4) binders should be avoided in patients with end-stage renal disease (ESRD). NaHCO3 may serve as an alternative therapy for metabolic acidosis with less risk of enhancing Al absorption.  相似文献   
7.
8.
Summary The plasma and urine concentrations of famotidine, a new, potent H2-receptor antagonist, have been measured in 16 healthy young adults, 8 healthy elderly people and 18 patients with varying degrees of renal dysfunction after intravenous administration.Both the plasma elimination and renal excretion of famotidine were decreased in the elderly volunteers and renal patients. The renal clearance of famotidine averaged 4.43 ml/min/kg (310 ml/min) in normal young volunteers, which exceeded the mean creatinine clearance 1.55 ml/min/kg (109 ml/min), suggesting net secretion is a significant mechanism for elimination of famotidine.The ratio of famotidine renal clearance to creatinine clearance decreased as creatinine clearance decreased; these results suggest that the deterioration in the secretion process was much faster than that in glomerular filtration and are incompatible with the intact nephron hypothesis. Nevertheless, both total body clearance and renal clearance were significantly correlated with creatinine clearance.The apparent half-life was also significantly correlated with creatinine clearance. Since famotidine is essentially free of dose-related adverse effects, dose adjustment in patients with mild renal insufficiency and in elderly people is not required; however, either a prolonged dosing interval or a decrease in daily dose during long-term therapy may be adapted for the patients with severe renal insufficiency to avoid accumulation and the potential undesirable effects.  相似文献   
9.
The authors describe 32 children between 2 and 15 years of age who had hydrocephalus that was only clinically manifest late in life. The clinical picture of these children did not suggest an obvious increase in intracranial pressure; instead, the presenting signs were rather nonspecific and included macrocrania, mild psychomotor retardation, unsteady gait, increased muscle tone and deep tendon reflexes in the lower limbs, impaired ocular movement, epilepsy, and endocrine dysfunction. Their histories suggest the possible causes of the ventricular dilation in about one third of the cases were: perinatal hemorrhage, leptomeningitis, neurofibromatosis, and untreated aneurysm of the great vein of Galen. In 20 patients, however, no positive anamnestic findings were reported. CT scan revealed triventricular dilation in more than half of the cases; tetraventricular dilation was present in 6 patients, and biventricular dilation in the remaining subjects. All children underwent CSF shunting, which resulted in complete recovery in all but 2 cases. The most frequently recorded surgical complication was postoperative subdural effusion (7 subjects), which required surgical treatment in only 2 cases.Presented at the 15th Annual Scientific Meeting of the International Society for Pediatric Neurosurgery, New York, 1987  相似文献   
10.
OBJECTIVE: Nondipping status (<10% decrease in blood pressure [BP] from awake to asleep) has been associated with end-organ disease (stroke and left ventricular hypertrophy) in adults. Nondipping status has also been observed in 30% of healthy African American adolescents, but little is known about the correlates of nondipping status in adolescents. This study examined the relationship between violence exposure, catecholamine excretion, and BP nondipping status in 56 healthy African American adolescents (27 boys, 29 girls; ages 11-18 years). METHODS: Participants completed the Survey of Exposure to Community Violence, wore an ambulatory BP monitor and provided one timed day and night urine collection for determination of epinephrine and norepinephrine excretion. RESULTS: Boys had higher daytime epinephrine (5.1 +/- 3.3 vs. 2.6 +/- 2.3 ng/min, p < .001) and norepinephrine excretion (29.2 +/- 25.1 vs. 16.5 +/- 14.9 ng/min, p < .05) and showed a greater prevalence of mean BP nondipping status than girls (37% vs. 10%, p < .03). Mean BP nondipping status was positively associated with victimization (r = 0.42, p < .0001). Regression analyses indicated a significant interaction between hearing about violence and sex for predicting daytime epinephrine (p < .02), with male nondippers showing a stronger positive association (partial correlation = 0.59, p < .05) than females (partial correlation = 0.03, p = NS). Logistic regressions also demonstrated a significant interaction between hearing about violence and sex for predicting mean BP dipping status, with male nondippers reporting the greatest exposure. CONCLUSIONS: Mean BP nondipping was associated with victimization in both boys and girls. Boys who reported higher levels of hearing about violence showed greater daytime epinephrine excretion and were more likely to be classified as nondippers.  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