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   815篇
  免费   28篇
  国内免费   6篇
耳鼻咽喉   30篇
儿科学   45篇
妇产科学   30篇
基础医学   54篇
口腔科学   11篇
临床医学   62篇
内科学   181篇
皮肤病学   20篇
神经病学   48篇
特种医学   52篇
外科学   158篇
综合类   16篇
预防医学   25篇
眼科学   34篇
药学   30篇
肿瘤学   53篇
  2023年   6篇
  2022年   14篇
  2021年   21篇
  2020年   22篇
  2019年   25篇
  2018年   24篇
  2017年   20篇
  2016年   17篇
  2015年   25篇
  2014年   19篇
  2013年   48篇
  2012年   66篇
  2011年   77篇
  2010年   31篇
  2009年   29篇
  2008年   58篇
  2007年   42篇
  2006年   56篇
  2005年   35篇
  2004年   31篇
  2003年   37篇
  2002年   34篇
  2001年   17篇
  2000年   12篇
  1999年   14篇
  1998年   4篇
  1997年   5篇
  1996年   13篇
  1995年   1篇
  1994年   3篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   3篇
  1987年   5篇
  1986年   4篇
  1985年   4篇
  1982年   6篇
  1980年   1篇
  1978年   2篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1974年   2篇
  1971年   1篇
  1970年   1篇
  1968年   2篇
  1966年   1篇
排序方式: 共有849条查询结果,搜索用时 15 毫秒
41.
Background : Recent studies suggest that coeliac disease (CD) is one of the commonest, life-long disorders in Italy. The aims of this multicentre work were: (a) to establish the prevalence of CD on a nationwide basis; and (b) to characterize the CD clinical spectrum in Italy. Patients and methods : Fifteen centres screened 17201 students aged 6–15 years (68.6% of the eligible population) by the combined determination of serum IgG- and IgA-antigliadin antibody (AGA) test; 1289 (7.5%) were IgG and/or IgA-AGA positive and were recalled for the second-level investigation; 111 of them met the criteria for the intestinal biopsy: IgA-AGA positivity and/or AEA positivity or IgG-AGA positivity plus serum IgA deficiency. Results : Intestinal biopsy was performed on 98 of the 111 subjects. CD was diagnosed in 82 subjects (75 biopsy proven, 7 not biopsied but with associated AGA and AEA positivity). Most of the screening-detected coeliac patients showed low-grade intensity illness often associated with decreased psychophysical well-being. There were two AEA negative cases with associated CD and IgA deficiency. The prevalence of undiagnosed CD was 4.77 × 1000 (95% CI 3.79–5.91), 1 in 210 subjects. The overall prevalence of CD, including known CD cases, was 5.44 × 1000 (95% CI 4.57–6.44), 1 in 184 subjects. The ratio of known to undiagnosed CD cases was 1 in 7. Conclusions : These findings confirm that, in Italy, CD is one of the most common chronic disorders showing a wide and heterogeneous clinical spectrum. Most CD cases remain undiagnosed unless actively searched.  相似文献   
42.
BACKGROUND/AIMS: The aim of this study was to evaluate the predictive accuracy of P-POSSUM and O-POSSUM models on patients undergoing elective gastric resection. METHODOLOGY: P-POSSUM and O-POSSUM predictor equations for mortality were applied retrospectively to 126 patients who had undergone elective gastrectomy for cancer. Observed mortality rates were compared with rates predicted by P-POSSUM and O-POSSUM using the Hosmer-Lemeshow goodness-of-fit test. Evaluation of the discriminative capability of both models was performed using receiver-operating characteristic (ROC) curve analysis. RESULTS: Overall fourteen deaths were observed. O-POSSUM predicted 15 deaths (chi2=14.61, p=0.13) and P-POSSUM predicted 20 deaths (chi2=25.41, p=0.002) using the Hosmer-Lemeshow test. ROC curves analysis revealed that O-POSSUM had better discriminatory power for mortality compared to P-POSSUM (area under curve=0.880, for O-POSSUM and area under curve=0.703 for P-POSSUM). CONCLUSIONS: These data suggest that O-POSSUM predicts mortality more accurately than P-POSSUM in patients undergoing elective gastrectomy for cancer.  相似文献   
43.
Hydroxyurea (HU) has been shown to reduce the frequency of vaso-occlusive manifestations in both adults and children with sickle cell disease (SCD), and the induction of hemoglobin F (HbF) is thought to be the underlying mechanism responsible for clinical improvement in some patients. However, there exists no good correlation between the amount of HbF increase and clinical response. Recent studies suggest that increased activity of the coagulation system may be important in the pathogenesis of vascular occlusion in sickle cell disease. To analyze the effect of HU on the coagulation system in children, the authors studied the levels of some coagulation factors and natural inhibitors. Eleven children who had been treated with HU because of SCD (5 patients), sickle- β-thalassemia (3 patients), and β-thalassemia intermedia (3 patients) were enrolled in the study. Levels of the coagulation factors II, V, VII, VIII, IX, X, XI, and XII, and of protein C and protein S, prothrombin times, activated partial thromboplastine times, thrombin times, and reptilase times were measured before the treatment and at the 5th or 6th months of HU therapy when the patients were in a steady-state condition. There was a decrease in all of the coagulation factors except for FIX and FXII and in inhibitors such as protein C and protein S. However, statistically significant decreases were observed only in factor VIII and protein C levels. The rates of decrease were 54.8 and 12.5% ( p = .015 and p = .018) in FVIII and protein C, respectively. This result shows that HU has significant effects on the coagulation and natural inhibitory systems.  相似文献   
44.
This study was performed to investigate the quality of different intravenous sedation techniques, and the correlation between the Bispectral Index (BIS) values and the Observer's Assessment of Alertness/Sedation (OAA/S) scores. Eighty patients undergoing sinonasal surgery were randomly assigned to one of four groups. Group MF received midazolam and fentanyl, group PF received propofol and fentanyl, group MR received midazolam and remifentanil, and group PR received propofol and remifentanil. Heart rate and mean arterial pressure values were not different among the groups. SpO2 decreased only after intravenous medication in groups MF and MR (P < 0.017). Emesis was less common with propofol. A positive relationship existed between the BIS values and OAA/S scores during the operation in all groups and the strongest correlation was observed in group PR (r = 0.565 and P < 0.001). In conclusion, these four intravenous sedation techniques did not change mean arterial pressure, heart rate or SpO2 clinically and produced a similar level of light sedation. The BIS was useful for monitoring of sedation during sinonasal surgery under local anaesthesia with intravenous sedation.  相似文献   
45.

Objective

The aim of the study was to investigate the effect of intragastric balloon therapy on left ventricular function and left ventricular mass in a cohort of morbidly obese patients.

Subjects and Methods

A prospective trial was performed in a cohort of 17 class II and class III morbidly obese individuals. The intragastric balloon was retained in the stomach for an average of 6 months. Conventional and tissue Doppler echocardiography were performed in all patients before and after the procedure.

Results

The mean age of the study participants was 36 ± 10 years (range: 18–55). The mean body mass index was significantly decreased following the intragastric balloon insertion procedure (44 ± 8 vs. 38 ± 5, p < 0.001). The left ventricular mass index and left atrial volume index were significantly decreased following the procedure (112 ± 21 vs. 93 ± 17, p = 0.001 and 20 ± 6 vs. 14 ± 5, p = 0.02, respectfully). In addition, the ratio of mitral peak early diastolic velocity to tissue Doppler-derived peak diastolic velocity and tissue Doppler echocardiography-derived left ventricular myocardial performance index were decreased significantly following the procedure (9.5 ± 1.9 vs. 7.7 ± 1.5, p = 0.002 and 0.57 ± 0.11 vs. 0.46 ± 0.06, p = 0.001, respectively).

Conclusions

Intragastric balloon therapy resulted in significant weight reduction in morbidly obese patients. This weight reduction was associated with improved left ventricular function.Key Words: Obesity, Intragastric balloon therapy, Echocardiography, Tissue Doppler  相似文献   
46.
BACKGROUND: Protein energy malnutrition (PEM) is a common pediatric health problem in developing countries. Although the clinical features of PEM are well known, its pathophysiology is still unclear. Free radicals have been implicated in pathogenesis of PEM. In the present study, oxidant/anti-oxidant status in marasmus was investigated. METHODS: Red cell glutathione, glutathione peroxidase and superoxide dismutase and their related cofactors, serum selenium and copper, were studied in marasmic and control children. Serum lipid peroxidation was also evaluated to assess oxidative stress. RESULTS: The red cell glutathione levels and glutathione peroxidase activities were found to be significantly lower in the marasmic children than in the controls. Red cell superoxide dismutase (SOD) activity was not different between two groups. Serum selenium and copper concentrations were significantly lower in the marasmic children than in the control subjects. The malondialdehyde concentration, which is an index of lipid peroxidation, was significantly higher in the marasmic group compared with the controls. CONCLUSION: The anti-oxidant defense system was affected in marasmic children. Reduced anti-oxidant status and increased oxidative stress occurs in marasmic children.  相似文献   
47.
Leiomyomas of the external genitalia are uncommon soft tissue tumors. We report the case of a 47-year-old woman with perineal leiomyomas mimicking Bartholin's gland mass according to the preoperative magnetic resonance imaging (MRI) findings. Leiomyomas in the vulvar region should be differentiated from complicated Bartholin’s gland cysts and preoperative MRI findings may be misleading. The complete surgical excision should be the choice of treatment  相似文献   
48.
Aim: The aim of the student is to assess whether adolescents with type 1 diabetes mellitus (T1DM) in Italy differ from their healthy peers in regard to risky behaviour. Methods: Data were collected from 215 patients, aged 14 ± 2 years with a mean disease duration of 7 ± 5 years. The control group was comprised of 464 healthy adolescents recruited among high school students. Each patient completed an anonymous confidential questionnaire to determine the prevalence of sexual behaviour, alcohol and tobacco consumption, illicit drug use, and, among patients with diabetes and frequency of mismanagement related to diabetes care. Results: Compared with controls, subjects with diabetes showed a similar rate of sexual intercourse among males and lower rates among females (34.8% vs 35.5%, p NS and 29.4% vs 41.4%, p < 0.05, respectively). Males in the diabetes group reported a higher rate of tobacco use, whereas females showed similar or higher rates of use for every illicit drug studied. Among patients with diabetes, those who are engaged in risky behaviour showed a higher rate of treatment mismanagement (76% vs 34%, p < 0.01). Conclusion: Adolescents with T1DM are as likely as their healthy peers to engage in risky behaviour, indicating the potential benefit of anticipatory guidance concerning glycaemic control and increased risk of acute and chronic complications.  相似文献   
49.
50.
A set of four types of benzazoles, 1, 2, 4-triazole, and pyridine-2-carbonitrile/-2-carbothioamide substituted with 1-naphthylmethylsulfanyl or pyridylmethylsulfanyl was prepared to modify the structure of benzylsulfanyl derivatives of the above-mentioned heterocycles. The compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, M. avium, and two strains of M. kansasii. The activities were expressed as the minimum inhibitory concentration (MIC). The MIC values fall into a range of 2 to >1000 micromol/L. Introduction of a pyridyl moiety into the molecule mostly decreased the activity. A naphthyl moiety did not influence the activity in comparison with a phenyl. The most active substances were 4-(3-pyridylmethylsulfanyl)pyridine-2-carbothioamide (7b) (MIC = 2 - >62.5 micromol/L) and 4-(1-naphthylmethylsulfanyl)pyridine-2-carbothioamide (7d) (MIC = 2 - >32 micromol/L).  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