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   340篇
  免费   14篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   8篇
妇产科学   28篇
基础医学   32篇
口腔科学   6篇
临床医学   21篇
内科学   54篇
皮肤病学   1篇
神经病学   27篇
特种医学   24篇
外科学   58篇
综合类   1篇
预防医学   35篇
药学   18篇
肿瘤学   40篇
  2023年   4篇
  2022年   9篇
  2021年   8篇
  2020年   3篇
  2019年   9篇
  2018年   12篇
  2017年   14篇
  2016年   18篇
  2015年   13篇
  2014年   12篇
  2013年   13篇
  2012年   26篇
  2011年   17篇
  2010年   11篇
  2009年   7篇
  2008年   12篇
  2007年   13篇
  2006年   17篇
  2005年   16篇
  2004年   14篇
  2003年   12篇
  2002年   6篇
  2001年   14篇
  2000年   12篇
  1999年   4篇
  1998年   2篇
  1997年   2篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1992年   2篇
  1991年   3篇
  1990年   4篇
  1989年   2篇
  1987年   6篇
  1986年   6篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1976年   1篇
  1975年   2篇
  1974年   1篇
  1972年   4篇
  1971年   3篇
  1969年   4篇
  1968年   1篇
  1966年   1篇
  1958年   1篇
  1956年   1篇
  1935年   1篇
排序方式: 共有355条查询结果,搜索用时 15 毫秒
1.
2.
A recent large increase in Caesarean section (CS) in Italy was the initial stimulus for a study to identify risk factors for CS and, if possible, to suggest strategies to counteract the rise. The study was conducted in three hospitals where a wide range of individual variables was collected from the clinical records and from personal interviews. Crude CS rates and odds ratios were evaluated for each single variable while logistic regression has been used to investigate possible confounding factors. The study involved 1316 consecutive deliveries. Crude CS rates were 29.4%, 15.7% and 16.1%. Variables identified as high risk factors were pre-eclampsia, previous CS, breech and other non-vertex presentations. Antenatal care under an obstetrician working in the same hospital, a low number of antenatal consultations, previous miscarriages, offer (by obstetrician) and request (by women) for CS showed significantly high odds ratios (ORs). Previous live births was strongly negatively associated with CS. No relationship between type of delivery and social status was observed while a physician factor was detected in all three hospitals where rates for different physicians ranged from 0% to 52.8%. Apart from the main medical indications for Caesarean section (previous CS, breech presentation), the results seem to indicate that individual practice style may be an important determinant of the wide variation in the rates of Caesarean delivery. While this may have been suspected before this study, these results are the first hard data to indicate that, in Italy, CS is widely performed for non-medical reasons.  相似文献   
3.
Our aim was to assess the association between a priori defined dietary patterns and incident depressive symptoms. We used data from The Maastricht Study, a population-based cohort study (n = 2646, mean (SD) age 59.9 (8.0) years, 49.5% women; 15,188 person-years of follow-up). Level of adherence to the Dutch Healthy Diet (DHD), Mediterranean Diet, and Dietary Approaches To Stop Hypertension (DASH) were derived from a validated Food Frequency Questionnaire. Depressive symptoms were assessed at baseline and annually over seven-year-follow-up (using the 9-item Patient Health Questionnaire). We used Cox proportional hazards regression analyses to assess the association between dietary patterns and depressive symptoms. One standard deviation (SD) higher adherence in the DHD and DASH was associated with a lower hazard ratio (HR) of depressive symptoms with HRs (95%CI) of 0.78 (0.69–0.89) and 0.87 (0.77–0.98), respectively, after adjustment for sociodemographic and cardiovascular risk factors. After further adjustment for lifestyle factors, the HR per one SD higher DHD was 0.83 (0.73–0.96), whereas adherence to Mediterranean and DASH diets was not associated with incident depressive symptoms. Higher adherence to the DHD lowered risk of incident depressive symptoms. Adherence to healthy diet could be an effective non-pharmacological preventive measure to reduce the incidence of depression.  相似文献   
4.
Zusammenfassung Ziel unserer Untersuchung ist es, die Kenntnisse und Einstellungen zum Thema AIDS sowie das sexuelle Verhalten der Jugendlichen zu erforschen. Die im Jahr 1993 begonnene Untersuchung wird durch die Aussendung eines anonymen Fragebogens an eine randomisierte Mustergruppe von 52 000 Jugendlichen im Alter von 19 bis 24 Jahren aus 363 Gemeinden durchgeführt. Für die gegenwärtige Zwischenauswertung sind 6929 der 18 132 bis zum jetzigen Zeitpunkt ausgesandten Fragebogen analysiert worden, wobei alle italienischen Regionen proportional eingeschlossen sind. Unsere Daten haben bislang ergeben, dass das Verhalten der Jugendlichen nicht immer darauf hinzielt, das Risiko einer sexuellen Übertragung der HIV-Infektion zu vermeiden. Es sind aber immerhin zwei Veränderungen beobachtet worden: Ein Ansteigen des Durchschnittsalters beim ersten Geschlechtsverkehr und ein häufigerer Gebrauch von Kondomen.
Sexual behaviour of young Italians as regards risk of contracting AIDS
Summary The objective of this survey is to evaluate knowledge and sexual behaviour among young Italians (19 to 24 years). The project, began in 1993, is being carried out through an anonymous postal questionnaire, sent to a representative sample of the young Italian population (a total of 52 000 people from 363 Italian towns). In the present intermediate evaluation, we have analysed 6929 of the 18 132 questionnairs sent till now, with all Italian regions being proportionally included. Our data show that, after sexual activity has been started, it hardly seems to be limited to monogamy or to be always regulated by AIDS-preventing practices. Data show that the age of the first sexual intercourse is increasing (after age 18) and that condoms are used more frequently, particularly in occasional sex.

Les comportements sexual des jeunes Italiens rapport le risque de contracter le SIDA
Résumé L'objectif de l'enquète est d'evaluer les connaissances et les comportements sexuels des jeunes Italiens d'àge consideré à risque pour l'infection du HIV (19–24 années). Le projet, débuté en 1993, à été mené avec un anonyme questionnaire postal, envoyé à l'echantillon représentatif des jeunes d'Italie (52 000 individues de 362 villes italiennes). Dans la présent partielle évaluation, nous avons evalué 6929 questionnaires des 18 132 jusqu'ici envoyé, toutes les régions italiennes sont proportionnellement compris. Les donnés montrent que, si les jeunes sont sexuellement actifs, c'est difficile qu'ils tendent à la monogamie ou qu'ils aient toujours pratiques sans risque du SIDA. Les donnés montrent aussi que l'âge du premier rapport sexuel est augmenté (àpres 18 ans) et que le preservatif est assez utilisé, surtout dans les rapports sexuels occasionels.
  相似文献   
5.
Tentorial Meningiomas. Report on Twenty-Seven Cases   总被引:14,自引:0,他引:14  
Summary ? Objective. Report our experience with 27 tentorial meningiomas (TM) surgically treated between 1985 and 1998.  Methods. The records of 27 patients with TMs were retrospectively reviewed for clinical presentation, neuroradiological evaluation, surgical treatment and long-term outcome. The extent of tumor resection was scored according to the Simpson's grading for tumor removal. Long-term results were evaluated according to the Glasgow Outcome Score (GOS).  Results. The average age was 53 years. Female predominance was 74%. The most common complaints at presentation were headaches (51%), gait ataxia (33%), memory disturbances (30%) and hypo-acousia (30%). A classification of TMs into 5 subgroups according to tumor site is proposed on the basis of imaging studies. A cerebrospinal fluid shunt was established prior to direct approach in 7 patients and as the sole procedure in one inoperable patient. Twenty-seven direct approaches were undertaken in 26 patients, including 17 infratentorial and 10 supratentorial approaches. Total tumor removal was achieved in 20 patients (77%) and subtotal removal in 6 (23%). Fifteen patients (55%) experienced 22 postoperative complications. One patient died three months after a subtotal resection (mortality=3,7%). With a mean follow-up of 54 months, all 26 survivors are currently alive with 23 having resumed their normal activities and 3 needing assistance. Five of 6 patients with subtotal resection survived and were followed for a period ranging from 72 to 132 months: none showed residual tumor progression and no re-operation was considered. An additional patient experienced a ?true? recurrence 6 years after total removal, with no tumor progression 2 years after his recurrence was recognized.  Discussion. The best surgical approach to TMs is still a controversial matter. The advantages and drawbacks of conventional versus transbasal approaches are reviewed. Our experience suggests that subtotal removal can be associated with long recurrence-free intervals and preserved quality of life. TMs located at the tentorial edge carried a definitely worse prognosis than peripheral forms.  相似文献   
6.
7.
AIMS: In human atrial myocytes (HuAM) two beta-adrenergic receptors (beta-AR) and four splicing-variants of the serotonin 5-HT(4) receptor are present. Multiple coupling with G stimulatory (G(s)) and G inhibitory (G(i)) proteins has been proposed for both beta(2)-AR and 5-HT((4b)) subtypes, but no functional data exist in HuAM. Serotonin (5-HT) and catecholamines are able to trigger arrhythmias in human atrium, but the underlying cellular mechanisms are not completely understood. The pacemaker current (I(f)) is an inward Na(+)/K(+) current, constitutively present in HuAM and directly modulated by cAMP; I(f) could play a role in triggering human atrial arrhythmias. This study evaluated the different G protein coupling of beta(1)-AR, beta(2)-AR and 5-HT(4) receptors by assessing the modulation of I(f) by selective stimuli. METHODS: HuAM were isolated from right atrial appendages and utilized for patch-clamp recording. The coupling of receptor subtypes with G(i) proteins was tested by incubating HuAM in pertussis toxin (PTX). RESULTS: Beta(1)-AR stimulation (Isoprenaline [ISO] + ICI 118,551), and 5-HT caused a concentration-dependent significant shift of the half activation potential of I(f) activation curve (DeltaV(h)), P < 0.01. beta(2)-AR stimulation (ISO 1 microM + CGP 20712A) also significantly shifted V(h) (P < 0.0001), but with DeltaV(h)[beta(2)-AR] significantly smaller than the effect caused by 1 microM beta(1)-AR stimulation (P < 0.05). Pre-treatment of HuAM with PTX did not alter the effect of beta(1)-AR stimulation (both 0.1 and 1 microM) and 1 microM 5-HT on I(f), but significantly increased the effect in response to beta(2)-AR stimulation and 0.1 microM 5-HT (P < 0.05 for both), thus suggesting a G(i) protein coupling of these receptors. CONCLUSIONS: Our results provide the first functional evidence of the different G protein coupling of beta(1)-AR, beta(2)-AR and 5-HT(4) receptors in HuAM. Further they support the view that I(f) current might play an important role in triggering catecholamines and serotonin-induced atrial arrhythmias.  相似文献   
8.
Purpose

To compare the accuracy of Contrast-Enhanced Spectral Mammography (CESM), MG, US, and breast MRI in estimating the size of breast lesions requiring surgery. The postoperative histology size of the lesion was used as the gold standard.

Material and methods

Two hundred thirty-three non-benign lesions in 189 patients were included in the analyses. All the selected patients underwent CESM and at least one other conventional diagnostic exam (US, MG, or MRI). Subsequently, all the patients underwent surgery preceded by cytological/histological examination. The largest diameter of the lesion at imaging was measured by a radiologist with more than 10 years’ experience and then compared with the size of the lesion in the histological sample at the surgery (gold standard).

Results

Among the 233 breast lesions, 196 were evaluated with US, 206 with MG and 160 with MRI. We found no statistically significant differences between size measurements using CESM and MRI compared with the measurements at the surgery (p value 0.63 and 0.51), whereas a significant difference was found for MG and US (p?<?0.001).

Conclusion

CESM is a reliable method for estimating the size of breast lesions: its performance seems superior to US and MG and comparable to MRI.

  相似文献   
9.
10.

Aims/hypothesis

Incretin effect—the potentiation of glucose-stimulated insulin release induced by the oral vs the i.v. route—is impaired in dysglycaemic states. Despite evidence from human islet studies that NEFA interfere with incretin function, little information is available about the effect in humans. We tested the impact of acute bidirectional NEFA manipulation on the incretin effect in humans.

Methods

Thirteen individuals with type 2 diabetes and ten non-diabetic volunteers had a 3 h OGTT, and, a week later, an i.v. isoglycaemic glucose infusion (ISO; OGTT matched). Both pairs of studies were repeated during an exogenous lipid infusion in the non-diabetic volunteers, and following acipimox administration (to inhibit lipolysis) in people with diabetes. Mathematical modelling of insulin secretion dynamics assessed total insulin secretion (TIS), beta cell glucose sensitivity (β-GS), glucose-induced potentiation (PGLU) and incretin-induced potentiation (PINCR); the oral glucose sensitivity index was used to estimate insulin sensitivity.

Results

Lipid infusion increased TIS (from 61 [interquartile range 26] to 78 [31] nmol/m2 on OGTT and from 29 nmol/m2 [26] to 57 nmol/m2 [30] on ISO) and induced insulin resistance. PINCR decreased from 1.6 [1.1] to 1.3 [0.1] (p?<?0.05). β-GS, PGLU and glucagon, glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP) responses were unaffected. Acipimox (lowering NEFA by ~55%) reduced plasma glucose and TIS and enhanced insulin sensitivity, but did not change β-GS, PINCR, PGLU or glucagon, GLP-1 or GIP responses. As the per cent difference, incretin effect was decreased in non-diabetic participants and unchanged in those with diabetes.

Conclusions/interpretation

Raising NEFA selectively impairs incretin effect and insulin sensitivity in non-diabetic individuals, while acute NEFA reduction lowers plasma glucose and enhances insulin sensitivity in people with diabetes but does not correct the impaired incretin-induced potentiation.
  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