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91.
In recent years several trials demonstrated the efficacy of implantable cardioverter-defibrillation (ICD) therapy in reducing cardiac and total mortality in patients affected by rapid ventricular tachycardia (VT) and/or ventricular fibrillation. Nevertheless, ICD do not prevent arrhythmia recurrences, thus being a palliative and not a curative treatment modality. The tolerance to ICD therapy varies greatly, and within individuals, this leading to a nonuniform acceptance of this form of therapy. The very frequent occurrence of VT, defined as an arrhythmic storm, may be a life threatening condition. The majority of ICD patients is under antiarrhythmic drug therapy, to reduce episodes of VT or to make antitachycardia pacing more effective by slowing the tachycardia rate. Drug therapy, however, may cause additional problems, and does not represent the optimal solution. The prevention of VT and/or ventricular fibrillation episodes and excessive ICD therapy, remains a worthwhile goal. Radiofrequency catheter ablation (RFCA) is a curative approach, and can be expected to reduce the frequency of recurrent VT episodes in the majority of patients. The combination of these treatment modalities (ICD and RFCA) is often described as hybrid therapy, implying that the two treatments act providing some form of synergism. In experienced centers, RFCA is now performed, regardless of whether the VT rate is rapid and/or is hemodynamically unstable. Newer mapping and ablation techniques are now available, enhancing the acute success rate of the procedure. In this review the most recent application of VT catheter ablation and the use of advanced mapping and ablation techniques will be discussed. 相似文献
92.
MARIA VITTORIA PITZALIS FILIPPO MASTROPASQUA FRANCESCO MASSARI CINZIA FORLEO REA PASSANTINO ROBERTO COLOMBO PAOLO TOTARO PAOLO RIZZON 《Pacing and clinical electrophysiology : PACE》1998,21(3):559-567
To evaluate the effect of a hydrophilic and a lipophilic β- blocker on the autonomic nervous system, 20 normal subjects were studied under baseline conditions and 7 days after being randomly assigned to metoprolol (200 mg/day), nadolol (80 mg/day), and placebo. Under each condition, the time-domain parameters were analyzed by means of 24-hour ECG monitoring and the frequency-domain parameters by means of the autoregressive method using 10-minute ECGs during rest, controlled respiration, and after a head-up tilt test. The alpha index (the gain in the relationship between the RR period and systolic arterial pressure variability) was also calculated. Both nadolol and metoprolol significantly increased all of the time-domain parameters except the standard deviation of the RR intervals; they also modified the frequency-domain parameters. Both blunted the significant reduction in the high frequency (HF) component and alpha index during tilt. In normal subjects, hydrophilic and lipophilic β-blockers similarly modify the time- and frequency-domain parameters that are particularly evident when high sympathetic tone is present (during daytime and tilt). The value of the alpha index was increased by both β-blockers in the HF, but not in the low frequency band; this difference might be due to the fact that the former is a measure of the vagal component of the baroreflex control and the latter a measure of the sympathethic component. The effects of hydrophilic and lipophilic β-blockers on the time- and frequency-domain parameters of heart rate variability are similar. 相似文献
93.
FRANCESCO ENIA RENATO LO MAURO FRANCESCO MESCHISI FRANCESCO PAOLO SABELLA 《Pacing and clinical electrophysiology : PACE》1991,14(7):1093-1097
Five years prior to presentation, a 29-year-old woman received a transvenous pacemaker (DDD) for sick sinus syndrome and nodo-hisian pathology. After pacemaker insertion, she complained of recurrent febrile episodes. Her pacemaker related endocarditis was quite unusual for the infecting organism (a micrococcus) and for an acquired tricuspid valve stenosis. The suspected cause was confirmed at surgery. 相似文献
94.
JAMES L. CHRISTIANSEN PAOLO GUCCIONE ARTHUR GARSON Jr . 《Pacing and clinical electrophysiology : PACE》1996,19(9):1296-1303
Measurement of the QT interval on standard ECG has diagnostic importance in the congenital long QT syndrome, in pharmacological therapy of arrhythmias, as well as in ischemic heart disease. It has been suggested that QT prolongation on ambulatory ECG (Holter) may have similar importance. To assess agreement between methods, QT interval measurement on standard ECG was compared to that on Holter. Simultaneously obtained ECG and Holter tracings (25 mm/s) of the same complexes in leads V1 and V5 were studied in 14 patients (age range 4–36 years). ECG pairs (n = 100, 49 V1 and 51 V5) were compared over a range of QT interval from 300–620 ms, as determined with the use of calipers by two observers blinded to pairing relationship. Correlation between methods was high for both observers (observer 1: r[V1] = 0.872, r[V5] = 0.973; observer 2: r[V1] = 0.972, r[V5] = 0.988), and interobserver variability was small (> 85% of measurements within 20 ms). As compared to ECG, Holter underestimated QT interval in V1 mean difference (QT [Holter]—QT [ECG]) observer 1 (-23 ms, P < 0.001), observer 2 (-7 ms, P < 0.05), and overestimated QT in V5, mean difference observer 1 (+ 13 ms, P < 0.001), observer 2 (+13 ms, P < 0.001). However, individual variation between methods was wide, as expressed by the difference between individual measurements (95% confidence interval [V1]: observer 1 [-99 to +53 ms] observer 2 [-47 to +33 ms]; [V5]: observer 1 [-33 to +59 ms] observer 2 [-17 to +43 ms]). Furthermore, when using the QTA (interval from onset of Q wave to apex of T wave) similar variability was observed. In the assessment of QT interval, potential sources of error of this magnitude could limit the clinical utility of ambulatory monitoring in detecting prolongation of the QT interval for diagnostic purposes. 相似文献
95.
96.
Ventricular Tachyarrhythmias in Patients With Hypertrophic Cardiomyopathy and Defibrillators: Triggers,Treatment, and Implications
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MARK S. LINK M.D. KATY BOCKSTALL M.D. JONATHAN WEINSTOCK M.D. ALAWI A. ALSHEIKH‐ALI M.D. M.Sc. CHRISTOPHER SEMSARIAN M.B.B.S. Ph.D. M.P.H. N. A. MARK ESTES M.D. III PAOLO SPIRITO M.D. TAMMY S. HAAS R.N. ETHAN J. ROWIN M.D. MARTIN S. MARON M.D. BARRY J. MARON M.D. 《Journal of cardiovascular electrophysiology》2017,28(5):531-537
97.
HAW‐KWEI HWANG M.D. PAOLO RUSCONI M.D. ELIOT ROSENKRANZ M.D. MING‐LON YOUNG M.D. M.P.H. 《Pacing and clinical electrophysiology : PACE》2010,33(8):e68-e71
An 11‐year‐old boy, who underwent bicaval orthotopic heart transplantation for idiopathic dilated cardiomyopathy, had a focal atrial tachycardia originating from the donor superior vena cava. The pathogenesis of this tachycardia may be related to transplant rejection or transplant vasculopathy. Radiofrequency catheter ablation can eliminate this unique tachycardia and result in hemodynamic improvement. (PACE 2010; e68–e71) 相似文献
98.
GIULIANO SILIGARDI ALEX F. DRAKE PAOLO MASCAGNI DAVID J. ROWLANDS FRED BROWN WILLIAM A. GIBBONS 《Chemical biology & drug design》1991,38(6):519-527
The circular dichroism spectrum of the 20-residue immunogenic peptide from the foot-and-mouth disease virus (VP1; 141-160 of serotype A, subtype 12) was solvent- and temperature-dependent. Careful solvent titration revealed two isodichroic points and plateaux consistent with stepwise unfolding of specific stable conformations. Variable temperature studies in cryogenic solvents and urea perturbation were consistent with the existence of three conformational moieties, the left-handed extended helix, the a-helix, and the α-helix. The number of residues in each helix was confirmed by CD spectral simulations. The strategy described here can be used to determine the components of a conformational equilibrium and their statistical weights, to study peptide folding and unfolding and to determine the bioactive conformation(s) of linear peptides. The conclusions were supported by 2D-NMR studies. A new mechanism for the stabilization of left-handed extended helices and destabilization of a-helices by urea is proposed. The structure of the peptide as resolved by CD spectroscopy is of particular significance since the conformation of this antigenic sequence in situ has so far not been solved by X-ray crystallography. 相似文献
99.
PAOLO ALBONI SALVATORE SCARF GIUSEPPE FUCÁ NELLY PAPARELLA PANAYIU YANNACOPULU 《Pacing and clinical electrophysiology : PACE》1995,18(5):980-985
The hemodynamics of induced atrial fibrillation (AF) was investigated in 15 patients (ages 58 ± 11 years) with paroxysmal AF presenting without organic heart disease or hypertension. A hemodynamic study was performed both during sinus rhythm and after the induction of AF. The mean heart rate increased from 73 ± 11 to 128 ± 18 beats/min (P < 0.001) after AF. Systolic and mean aortic pressures did not significantly change, and diastolic aortic pressure increased (78 ± 11 vs 89 ± 12 mmHg, P < 0.01). Left ventricular enddiastolic pressure decreased during AF (9 ± 3 vs 6 ± 2.6 mmHg, P < 0.005), whereas mean pulmonary wedge pressure increased (8 ± 2 vs 12 ± 4 mmHg, P < 0.001). Systolic pulmonary arterial pressure did not show significant variations, and there was a slight but statistically significant increase in the diastolic and mean pulmonary arterial pressures (P < 0.01). The right ventricular end-diastolic pressure decreased during AF (5.6 ± 2 vs 3.8 ± 2 mmHg, P < 0.01 j, whereas mean right atrial pressure showed a trend toward an increase. Stroke volume markedly decreased (P < 0.001) while the cardiac index did not significantly change. Systemic vascular resistance, pulmonary arteriolar resistance, and the arteriovenous O2 difference showed no significant variations after the induction of AF. These results suggest that in subjects without organic heart disease, paroxysmal AF is well tolerated hemodynamicaily, and the rise in the atrial pressures during AF is not related to an increase in the ventricular end-diastolic pressure. 相似文献
100.
PAOLO RUZZA ANDREA CALDIIRAN BRUNO FILIPPI ARIANNA DONELLA-DEANA LORENZO A. PINNA GIANFRANCO BORIN 《Chemical biology & drug design》1993,41(3):291-299
The transforming gene of Abelson murine leukaemia virus (v-abl) codes for a membrane-associated tyrosine-specific protein kinase (abl TPK). Analysis of the v-abl gene has shown that both the fibroblast-transforming and tyrosine-protein kinase activities reside within a minimal region encoding a protein of 43 kDa (p43v-abl), which represents the most active, isolated form of this enzyme. Since the cellular substrates for p43 v-abl are yet to be identified, we synthesized by classical solution methods the octapeptide H-Gly-Asp-Thr-Tyr-Thr-Ala-His-Ala-OH, corresponding to the structural sequence of the main putative autophosphorylation site (Tyr 515) of the abl TPK, as well as some of its analogs modified in positions -2, -1, + 1 and + 3. The synthetic peptides were tested as substrates for the p43v-abl. The kinetic data obtained indicate that the rates of their phosphorylation vary considerably depending on the sequence of the peptide, as expected. As a rule, no significant increment of the efficiency results from each substitution in the parent sequence. While the replacement of the two charged residues, namely Asp-2 and His-7, with neutral Ala is well tolerated, the substitution with amino acids bearing opposite charges is detrimental. The correlation between secondary structure of our synthetic octapeptides and their substrate recognition by p43v-abl was studied using CD and fluorescence spectroscopy in 5 mM Tris, in 98% TFE/Tris and in 30 mM SDS solutions. The comparison of the spectroscopic data with the kinetic parameters does not confirm a close relationship between the conformational properties of these peptides and their enzymatic role. 相似文献