全文获取类型
收费全文 | 328篇 |
免费 | 15篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 4篇 |
妇产科学 | 2篇 |
基础医学 | 43篇 |
口腔科学 | 26篇 |
临床医学 | 26篇 |
内科学 | 35篇 |
皮肤病学 | 2篇 |
神经病学 | 23篇 |
特种医学 | 16篇 |
外科学 | 67篇 |
预防医学 | 32篇 |
眼科学 | 2篇 |
药学 | 42篇 |
中国医学 | 3篇 |
肿瘤学 | 7篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 11篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 20篇 |
2014年 | 16篇 |
2013年 | 20篇 |
2012年 | 30篇 |
2011年 | 33篇 |
2010年 | 15篇 |
2009年 | 10篇 |
2008年 | 19篇 |
2007年 | 20篇 |
2006年 | 20篇 |
2005年 | 11篇 |
2004年 | 9篇 |
2003年 | 17篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
排序方式: 共有343条查询结果,搜索用时 15 毫秒
101.
PURPOSE: To evaluate the effectiveness of the "Dangerous Decibels" educational program in increasing students' knowledge and positively changing their attitudes and intended behaviors related to hearing and hearing loss prevention. METHOD: Baseline questionnaires were completed by 478 4th-grade students and 550 7th-grade students. Approximately half of the students in each grade received a 35-min interactive classroom presentation on hearing and hearing loss prevention. The remaining students served as comparison groups. Students who received the curriculum filled out questionnaires immediately after the presentation. All students filled out follow-up questionnaires 3 months after baseline. RESULTS: Fourth-grade students who participated in the Dangerous Decibels presentation exhibited significant improvements in knowledge and attitudes related to hearing and hearing loss prevention. These improvements were maintained 3 months after the presentation. Seventh-grade students also experienced long-term improvements in their knowledge base. However, attitudes and intended behaviors in 7th graders returned to baseline levels 3 months postpresentation. CONCLUSION: The Dangerous Decibels hearing loss prevention program was effective at producing long-term improvements in the knowledge base of 4th- and 7th-grade students. Future studies should include components on peer pressure and should incorporate repeated, multimodality interventions to increase the likelihood of long-term improvement in adolescents. 相似文献
102.
Ana Paula Dias Ribeiro Ana Cláudia Pavarina Livia Nordi Dovigo Iguatemy Lourenço Brunetti Vanderlei Salvador Bagnato Carlos Eduardo Vergani Carlos Alberto de Souza Costa 《Lasers in medical science》2013,28(2):391-398
Photodynamic therapy has been investigated as an alternative method of killing pathogens in response to the multiantibiotic resistance problem. This study evaluated the photodynamic effect of curcumin on methicillin-resistant Staphylococcus aureus (MRSA) compared to susceptible S. aureus (MSSA) and L929 fibroblasts. Suspensions of MSSA and MRSA were treated with different concentrations of curcumin and exposed to light-emitting diode (LED). Serial dilutions were obtained from each sample, and colony counts were quantified. For fibroblasts, the cell viability subsequent to the curcumin-mediated photodynamic therapy was evaluated using the MTT assay and morphological changes were assessed by SEM analysis. Curcumin concentrations ranging from 5.0 to 20.0 μM in combination with any tested LED fluences resulted in photokilling of MSSA. However, only the 20.0 μM concentration in combination with highest fluence resulted in photokilling of MRSA. This combination also promoted an 80% reduction in fibroblast cell metabolism and morphological changes were present, indicating that cell membrane was the main target of this phototherapy. The combination of curcumin with LED light caused photokilling of both S. aureus strains and may represent an alternative treatment for eradicating MRSA, responsible for significantly higher morbidity and mortality and increased healthcare costs in institutions and hospitals. 相似文献
103.
104.
Clóvis Grecco Lilian Tan Moriyama Alessandro Cosci Sebastião Pratavieira Vanderlei Salvador Bagnato Cristina Kurachi 《Lasers in medical science》2013,28(4):1177-1182
One of the clinical limitations of the photodynamic therapy (PDT) is the reduced light penetration into biological tissues. Pulsed lasers may present advantages concerning photodynamic response when compared to continuous wave (CW) lasers operating under the same average power conditions. The aim of this study was to investigate PDT-induced response when using femtosecond laser (FSL) and a first-generation photosensitizer (Photogem) to evaluate the induced depth of necrosis. The in vitro photodegradation of the sensitizer was monitored during illumination either with CW or an FSL as an indirect measurement of the PDT response. Healthy liver of Wistar rats was used to evaluate the tissue response. The photosensitizer was endovenously injected and 30 min after, an energy dose of 150 J?cm?2 was delivered to the liver surface. We observed that the photodegradation rate evaluated via fluorescence spectroscopy was higher for the FSL illumination. The FSL-PDT produced a necrosis nearly twice as deep when compared to the CW-PDT. An increase of the tissue temperature during the application was measured and was not higher than 2.5 °C for the CW laser and not higher than 4.5 °C for the pulsed laser. FSL should be considered as an alternative in PDT applications for improving the results in the treatment of bulky tumors where higher light penetration is required. 相似文献
105.
Francisco de Assis M. G. Rego Filho Maristela Dutra-Corrêa Gustavo Nicolodelli Vanderlei S. Bagnato Maria Tereza de Araujo 《Lasers in medical science》2013,28(1):215-222
Since about 40 years, laser-based surgical tools have been used in medicine and dentistry to improve clinical protocols. In dentistry, femtosecond lasers have been claimed to be a potential ablation tool. It would, however, be good to perform a more fundamental investigation to understand ablation interaction mechanisms and possible side effects, depending on different specific components of the target tissue. The goal of this study is to show the changes of ablation characteristics in the femtosecond regime at different levels of structural water within dental hard tissues. Thirty human teeth samples were split into three hydration groups and subdivided into dentin and enamel groups (n?=?5). The specimens were irradiated using a 70-fs Ti:sapphire laser (with a 1-kHz repetition rate and a 801-nm wavelength output). Ablation was performed using five different power levels and three exposure times. The results clearly show an inversely proportional dependence of the ablation threshold to the hydration level of the tissues. A known mathematical model was adapted in order to include the influence of the changes on the relative fractional composition of dental hard tissues. This analysis was consistent with the experimental results regarding the ablation threshold. High thermal and mechanical damages were observed as a high repetition rate had been applied. Macroscopic images and scanning electron microscopy images were used to preliminarily analyze both the thermal and mechanical damage thresholds, and their variations according to the hydration level present. By manipulating the hydration states, the modifications in the proportions of the molecules that build dental hard tissues clearly shift, and therefore, the characteristics of a plasma-induced ablation change. 相似文献
106.
Preventive aerobic training exerts a cardioprotective effect on rats treated with monocrotaline
下载免费PDF全文
![点击此处可从《International journal of experimental pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Francis Lopes Pacagnelli Ana Karênina Dias de Almeida Sabela Katashi Okoshi Thaoan Bruno Mariano Dijon Henrique Salomé Campos Robson Francisco Carvalho Antônio Carlos Cicogna Luiz Carlo Marques Vanderlei 《International journal of experimental pathology》2016,97(3):238-247
Pulmonary arterial hypertension (PAH) is a chronic disease which causes overload to the right ventricle. The effect of preventive training on cardiac remodelling in this condition is still unknown. This study aimed to evaluate the influence of preventive training on hypertrophy, heart function and gene expression of calcium transport proteins in rats with monocrotaline‐induced PAH. Thirty‐two male Wistar rats were randomly divided into four groups: S, sedentary control; T, trained control; SM, sedentary monocrotaline; and TM, trained monocrotaline. The preventive training protocol was performed on a treadmill for 13 weeks, five times/week. The first two weeks were adopted for adaptation to training with gradual increases in speed/time. The speed of the physical training from the third to tenth weeks was gradually increased from 0.9 to 1.1 km/h for 60 min. Next, monocrotaline was applied (60 mg/kg) to induce PAH and lactate threshold analysis performed to determine the training speeds. The training speed of the TM group in the following two weeks was 0.8 km/h for 60 min and the T = 0.9 km/h for 60 min; in the final two weeks, both groups trained at the same speed and duration 0.9 km/h, 60 min. Cardiac function was assessed through echocardiography, ventricular hypertrophy through histomorphometric analysis and gene expression through RT‐qPCR. Right cardiac function assessed through the peak flow velocity was SM = 75.5 cm/s vs. TM = 92.0 cm/s (P = 0.001), and ventricular hypertrophy was SM = 106.4 μm² vs. TM = 77.7 μm² (P = 0.004). There was a decrease in the gene expression of ryanodine S = 1.12 au vs. SM = 0.60 au (P = 0.02) without alterations due to training. Thus, we conclude that prior physical training exerts a cardioprotective effect on the right ventricle in the monocrotaline rat model. 相似文献
107.
Renata Claudino Rossi Franciele Marques Vanderlei Aline Fernanda Bernardo Naiara Maria de Souza Ana Clara Campagnolo Real Goncalves Ercy Mara Cipulo Ramos 《COPD》2014,11(1):39-45
Objective: The aim of the present study was to evaluate the effect of pursed-lip breathing (PLB) on cardiac autonomic modulation in individuals with chronic obstructive pulmonary disease (COPD) while at rest. Methods: Thirty-two individuals were allocated to one of two groups: COPD (n = 17; 67.29 ± 6.87 years of age) and control (n = 15; 63.2 ± 7.96 years of age). The groups were submitted to a two-stage experimental protocol. The first stage consisted of the characterization of the sample and spirometry. The second stage comprised the analysis of cardiac autonomic modulation through the recording of R-R intervals. This analysis was performed using both nonlinear and linear heart rate variability (HRV). In the statistical analysis, the level of significance was set to 5% (p ≤ 0.05). Results: PLB promoted significant increases in the SD1, SD2, RMSSD and LF (ms2) indices as well as an increase in α1 and a reduction in α2 in the COPD group. A greater dispersion of points on the Poincaré plots was also observed. The magnitude of the changes produced by PLB differed between groups. Conclusion: PLB led to a loss of fractal correlation properties of heart rate in the direction of linearity in patients with COPD as well as an increase in vagal activity and impact on the spectral analysis. The difference in the magnitude of the changes produced by PLB between groups may be related to the presence of the disease and alterations in the respiration rate. 相似文献
108.
109.
Femtosecond cluster studies of the solvated 7-azaindole excited state double-proton transfer
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Folmer DE Wisniewski ES Hurley SM Castleman AW 《Proceedings of the National Academy of Sciences of the United States of America》1999,96(23):12980-12986
Presented here are femtosecond pump-probe studies on the water-solvated 7-azaindole dimer, a model DNA base pair. In particular, studies are presented that further elucidate the nature of the reactive and nonreactive dimers and also provide new insights establishing that the excited state double-proton transfer in the dimer occurs in a stepwise rather than a concerted manner. A major question addressed is whether the incorporation of a water molecule with the dimer results in the formation of species that are unable to undergo excited state double-proton transfer, as suggested by a recent study reported in the literature [Nakajima, A., Hirano, M., Hasumi, R., Kaya, K., Watanabe, H., Carter, C. C., Williamson, J. M. & Miller, T. (1997) J. Phys. Chem. 101, 392-398]. In contrast to this earlier work, our present findings reveal that both reactive and nonreactive dimers can coexist in the molecular beam under the same experimental conditions and definitively show that the clustering of water does not induce the formation of the nonreactive dimer. Rather, when present with a species already determined to be a nonreactive dimer, the addition of water can actually facilitate the occurrence of the proton transfer reaction. Furthermore, on attaining a critical hydration number, the data for the nonreactive dimer suggest a solvation-induced conformational structure change leading to proton transfer on the photoexcited half of the 7-azaindole dimer. 相似文献
110.
Turrioni AP de Oliveira CF Basso FG Moriyama LT Kurachi C Hebling J Bagnato VS Costa CA 《Lasers in medical science》2012,27(1):191-196
The influence of dentin permeability on transdentinal LED light propagation should be evaluated since this kind of phototherapy
may further be clinically used to stimulate the metabolism of pulp cells, improving the healing of damaged pulps. This study
evaluated the influence of the dentin permeability on the transdentinal LED light (630 nm) transmission. Forty-five 0.5-mm-thick
dentin disks were prepared from the coronal dentin of extracted sound human molars. An initial measurement of transdentinal
LED light transmission was carried out by illuminating the discs in the occlusal-to-pulpal direction onto a light power sensor
to determine light attenuation. The discs were treated with EDTA for smear layer removal, subjected to analysis of hydraulic
conductance, and a new measurement of transdentinal LED light transmission was taken. Spearman’s correlation coefficient was
used for analysis of data and showed a weak correlation between dentin permeability and light attenuation (coefficient = 0.19).
This result indicates that higher or lower dentin permeability does not reflect the transdentinal propagation of LED light.
Significantly greater transdentinal propagation of light was observed after treatment of dentin surface with EDTA (Wilcoxon
test, p < 0.05). According to the experimental conditions of this in vitro study, it may be concluded that dentin permeability does
not interfere in the transdentinal LED light transmission, and that smear layer removal facilitates this propagation. 相似文献