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排序方式: 共有484条查询结果,搜索用时 15 毫秒
81.
Egehan Yetişkin Özlem Gündoğdu Derya Mete Neslihan Çelebioğlu Yunus Kara Gülşah Şanlı-Mohamed 《Chemical biology & drug design》2023,102(6):1448-1457
In this study, synthesis of novel isoindole-1,3-dione analogues bearig halo, hydroxy, and acetoxy groups at the position 4,5,6 of the bicyclic imide ring was performed to examine their potential anticancer effects against some cell lines. A multistep chemical pathway was used to synthesize the derivatives. The cytotoxic effect of trisubstituted isoindole derivatives were evaluated by determining cellular viability using the MTT assay against A549, PC-3, HeLa, Caco-2, and MCF-7 cell lines. The C-2 selective ring-opening products were obtained from the ring-opening reaction of 5-alkyl/aryl-2-hydroxyhexahydro-4H-oxireno[2,3-e]isoindole-4,6(5H)-diones with nucleophiles such as chloride (Cl−) and bromide (Br−) ions. In addition, the ring-opening products halodiols were converted to their related acetates. The anticancer activity of synthesized isoindole-1,3-dione derivatives was investigated against HeLa, A549, MCF-7, PC3, and Caco-2 cells in vitro and resulted in varies cytotoxic effect depend on the group attached to the isoindole molecule. Furthermore, the evaluation of the antimicrobial action of trisubstituted isoindole derivatives against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria was assessed and found out selective inhibition of the both bacterial growth via different trisubstituted isoindole derivatives. The results of this work encourage further research on the potential utilization of trisubstituted isoindole derivatives as cytotoxic and antimicrobial agents. 相似文献
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Improved Efficacy of Mode Switching During Atrial Fibrillation Using Automatic Atrial Sensitivity Adjustment 总被引:5,自引:0,他引:5
CATHY T.F. LAM CHU-PAK LAU † SUM-KIN LEUNG HUNG-FAT TSE † GREGORY AYERS† 《Pacing and clinical electrophysiology : PACE》1999,22(1):17-25
Automatic mode switching (AMS) during atrial fibrillation (AF) in a dual chamber pacemaker is dependent on the accurate detection of an atrial electrogram. As atrial amplitude is often reduced during AF compared with sinus rhythm, this may result in failure of the AMS and a rapid ventricular response. In addition, undersensing of AF may result in competitive atrial pacing that sustains AF. We hypothesize that the use of automatic atrial sensitivity adjustment (ASA) may enhance AF sensing in a dual chamber pacemaker. We studied the AMS response with and without ASA of the Marathon DDDR (model 294–09, Intermedics, Inc.) pacemaker in 10 patients with paroxysmal AF. Intracardiac atrial electrograms during sinus rhythm and induced AF were recorded onto an analog tape recorder. They were replayed into the pacemaker to assess the AMS response at various starting atrial sensitivities from 3.5 to 0.8 mV with ASA activated and without. Atrial amplitude was reduced during AF. The higher the initial atrial sensitivity, the better is the AMS response and the lower the incidence of AF undersensing. The percentage of AMS before ASA ranged from 2.1% at an atrial sensitivity 3.5 mV to 95.6% at highest sensitivity of 0.5 mV (P < 0.05). After 10 minutes of ASA, the AMS response was improved from 1.7% to 50.6% and from 9.5% to 50.9% at starting atrial sensitivities of 3.5 mV and 2.5 mV, respectively (P < 0.05 in both instances). Undersensing during AF was also significantly reduced after ASA from 70% to 10% at a sensitivity of 3.5 mV and from 33.8% to 10.8% at 2.5 mV. There was no increase in oversensing. In four patients with paroxysmal AF with an implanted pacemaker, ASA improved AMS response in patients with a low implant atrial amplitude. In conclusion, efficacy of mode switching and AF sensing are dependent on the programmed atrial sensitivity, which can be enhanced with the use of ASA, particularly when P wave sensing during AF is borderline. 相似文献
84.
HUNG-FAT TSE M.B.B.S. CHU-PAK LAU M.D. CHEUK-MAN YU M.B.B.S. KATHY L.F. LEE M.B.B.S. GREGORY F. MICHAUD M.D. BRADLEY P. KNIGHT M.D. FRED MORADY M.D. S. ADAM STRICKBERGER M.D. 《Journal of cardiovascular electrophysiology》1999,10(9):1200-1209
INTRODUCTION: The purpose of our study was to evaluate the effect of repeated cardioversion with an implantable atrial defibrillator on the clinical outcome of patients with atrial fibrillation. METHODS AND RESULTS: The effects of the implantable atrial defibrillator on the total duration of atrial fibrillation, number of atrial fibrillation recurrences, and left atrial size were evaluated prospectively in 16 patients with atrial fibrillation (13 men and 3 women; mean age 58 +/- 11 years). Seven patients had no cardiovascular disease, 5 patients had hypertension, 3 patients had coronary heart disease, and 1 patient had congenital heart disease. Eight patients had paroxysmal atrial fibrillation for a mean duration of 80 +/- 61 months, and eight patients had persistent atrial fibrillation for a mean duration of 68 +/- 119 months. Except for one patient who received digoxin throughout the study, all patients received the same Class I or III antiarrhythmic agent throughout the study. The implantable atrial defibrillator successfully converted 50 (93%) of 54 spontaneous episodes of atrial fibrillation in 12 patients. During the initial 3 months of clinical follow-up, the atrial defibrillator documented 261 +/- 270 hours of atrial fibrillation compared with 126 +/- 172 hours (P = 0.01) during the subsequent 3 months. The left atrial size decreased from 4.4 +/- 0.7 cm at the time of atrial defibrillator implantation to 4.1 +/- 0.6 cm (P = 0.02) 6 months later. The number of atrial fibrillation recurrences did not change. These findings were observed in the absence of changes in drug therapy. No complications were observed. CONCLUSION: Restoration and maintenance of sinus rhythm in patients with atrial fibrillation by repeated cardioversion with an implantable atrial defibrillator was associated with a reduction in the total arrhythmia duration and a reduction in left atrial size. These results suggest that maintenance of sinus rhythm with the atrial defibrillator may reverse the remodeling process associated with atrial fibrillation. 相似文献
85.
Madiha Fathi Elmahaishi Rabaah Syahidah Azis Ismayadi Ismail Muhammad Syazwan Mustaffa Zulkifly Abbas Khamirul Amin Matori Farah Diana Muhammad Nor Kamilah Saat Rodziah Nazlan Idza Riati Ibrahim Nor Hapishah Abdullah Nurhidayaty Mokhtar 《Materials》2021,14(22)
This study presents the utilization of mill scale waste, which has attracted much attention due to its high content of magnetite (Fe3O4). This work focuses on the extraction of Fe3O4 from mill scale waste via magnetic separation, and ball milling was used to fabricate a microwave absorber. The extracted magnetic powder was ground-milled using two different techniques: (i) a conventional milling technique (CM) and (ii) mechanical alloying (MM) process. The Fe3O4/CM samples were prepared by a conventional milling process using steel pot ball milling, while the Fe3O4/MM samples were prepared using a high-energy ball milling (HEBM) method. The effect of milling time on the structural, phase composition, and electromagnetic properties were examined using X-ray diffraction (XRD) and a vector network analyzer (VNA). XRD confirmed the formation of magnetite after both the magnetic separation and milling processes. The results revealed that Fe3O4 exhibited excellent microwave absorption properties because of the synergistic characteristics of its dielectric and magnetic loss. The results showed that the Fe3O4/CM particle powder had a greater absorption power (reflection loss: <−10 dB) with 99.9% absorption, a minimum reflection loss of −30.83 dB, and an effective bandwidth of 2.30 GHz for 2 mm thick samples. The results revealed the Fe3O4/MM powders had higher absorption properties, including a higher RL of −20.59 dB and a broader bandwidth of 2.43 GHz at a matching thickness of only 1 mm. The higher microwave absorption performance was attributed to the better impedance matching property caused by the porous microstructure. Furthermore, the magnetite, Fe3O4 showed superior microwave absorption characteristics because of the lower value of permittivity, which resulted in better impedance matching. This study presents a low-cost approach method by reutilizing mill scale waste to fabricate a high purity crystalline Fe3O4 with the best potential for designing magnetic nano-sized based microwave absorbers. 相似文献
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Evaluation of Score for Neonatal Acute Physiology and Perinatal Extension II and Clinical Risk Index for Babies with additional parameters 下载免费PDF全文
89.
Susan Hattar Muhanad M. Hatamleh Faleh Sawair Mohammad Al-Rabab’ah 《Saudi Dental Journal》2015,27(2):70-74
Objectives
The aim of this study was to evaluate the strength of the bond between newly introduced self-adhesive resin cements and tooth structures (i.e., enamel and dentin).Methods
Three self-adhesive cements (SmartCem2, RelyX Unicem, seT SDI) were tested. Cylindrical-shaped cement specimens (diameter, 3 mm; height, 3 mm) were bonded to enamel and dentin. Test specimens were incubated at 37 °C for 24 h. The shear bond strength (SBS) was tested in a Zwick Roll testing machine. Results were analyzed by one-way ANOVA and t-test. Statistically significant differences were defined at the α = 0.05 level. Bond failures were categorized as adhesive, cohesive, or mixed.Results
The SBS values ranged from 3.76 to 6.81 MPa for cements bonded to enamel and from 4.48 to 5.94 MPa for cements bonded to dentin (p > 0.05 between surfaces). There were no statistically significant differences between the SBS values to enamel versus dentin for any given cement type. All cements exhibited adhesive failure at the resin/tooth interface.Conclusions
Regardless of their clinical simplicity, the self-adhesive resin cements examined in this study exhibit limited bond performance to tooth structures; therefore, these cements must be used with caution. 相似文献90.
Background: Alcohol consumption and some other dietary habits are thought to be associated with lung cancer incidence. However, the effects of these habits on lung cancer prognosis have been studied rarely. The purpose of this study was to address these gaps in knowledge. Methods: We studied a cohort of 1052 Chinese men in Hong Kong who were diagnosed with primary lung cancer. Cox proportional hazards models were used to determine the prognostic values of consumption of alcohol, fresh fruits or vegetables, meat, and fried or preserved food. Results: Compared with never drinkers, men who drank alcohol 1–3 days per week had a more favorable lung cancer prognosis (hazard ratio [HR]: 0.82, 95% confidence interval [CI] 0.68–0.97); however, this survival advantage was not significant in men who drank alcohol more frequently (HR: 0.91, 95% CI 0.73–1.14). Compared with men who consumed preserved or fried food only occasionally, men who consumed these foods frequently had a higher risk of lung cancer mortality (HR: 1.20, 95% CI 1.00–1.42). Conclusions: Occasional consumption of alcohol was a favorable survival factor for Chinese men with lung cancer. However, this survival benefit did not exist for frequent drinkers of alcohol. Chinese men with lung cancer who were frequent consumers of fried or preserved food had a worse prognosis than those who consumed these foods only occasionally. 相似文献