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51.
Objectives
This study’s purpose was to evaluate the depth of cure (DOC) and the variation of mechanical properties with depth of two nano-hybrid resin-based composites (RBCs) containing a novel monomer composition based on dimer-acid derivatives (h-Da) or rather tricyclodecane–urethane structure (TCD-urethane) compared to three conventionally formulated nano-hybrid RBCs based on hardness-profile measurements.Materials and methods
Specimens were produced through different layering techniques (bulk, incremental) and curing times (10, 20, and 40?s). Mechanical properties (Vickers hardness (HV), modulus of elasticity (E)) were evaluated every 100?μm longitudinally throughout the bisected samples using an automatic micro-hardness indenter. DOC was determined as the depth at which the 80% hardness cutoff value in relation to the surface hardness was reached. Results were compared using one- and multiple-way ANOVA, Tukey HSD post-hoc test (α?=?0.05) and partial eta-squared statistic.Results
Increasing curing time resulted in a significant increase in DOC. Generally, the novel-formulated materials showed higher DOC values. “Curing time” and “material” showed the strongest effect on DOC. Starting in 4?mm depth, significantly higher HV and E was reached for incremental compared to bulk-curing technique. Values in 0.1 and 2?mm depth (bulk, incremental) as well as in 4?mm depth (incremental) were independent from curing time, while in greater depths, values generally increased with curing time. “Filling technique” and “material” performed the strongest influence on mechanical properties.Conclusions
Within the limits of this study, the novel-formulated RBCs showed better performance concerning DOC compared to conventional materials.Clinical relevance
For cavities deeper than 3?mm, all tested materials should be placed incrementally to ensure adequate polymerization. In large cavities (≥6?mm), the lowest increment should be cured at least 40?s. The novel-formulated RBCs might be cured in comparatively bigger increments. 相似文献52.
Günther Deuschl Michael Schüpbach Karina Knudsen Marcus O. Pinsker Philippe Cornu Jörn Rau Yves Agid Carmen Schade-Brittinger 《Parkinsonism & related disorders》2013,19(1):56-61
Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an established treatment for advanced Parkinson's disease (PD) with disabling motor complications. However, stimulation may be beneficial at an earlier stage of PD when motor fluctuations and dyskinesia are only mild and psychosocial competence is still maintained. The EARLYSTIM trial was conducted in patients with recent onset of levodopa-induced motor complications (≤3 years) whose social and occupational functioning remained preserved. This is called ‘early’ here. The study was a randomized, multicenter, bi–national pivotal trial with a 2 year observation period. Quality of life was the main outcome measure, and a video-based motor score was a blinded secondary outcome of the study. Motor, neuropsychological, psychiatric and psychosocial aspects were captured by established scales and questionnaires. The patient group randomized here is the earliest in the disease course and the youngest recruited in controlled DBS trials so far. The methodological innovation for DBS-studies of this study lies in novel procedures developed and used for monitoring best medical treatment, neurosurgical consistency, best management of stimulation programming, blinded video assessment of motor disability, and prevention of suicidal behaviors. 相似文献
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Rafael Binato Junqueira Francielle Silvestre Verner Celso Neiva Campos Karina Lopes Devito Antônio Márcio Resende do Carmo 《Journal of endodontics》2013
Introduction
This in vitro study compared cone-beam computed tomography (CBCT) exam with different voxel sizes with digital periapical radiography in the detection of vertical root fractures in teeth with and without intracanal metallic posts.Methods
Eighteen single-rooted human teeth were endodontically treated, prepared for cast metal posts, and artificially fractured. After positioning the teeth in dry mandibular sockets, the samples were subjected twice (with and without posts) to digital periapical radiography at 3 different angles and to CBCT examinations with 2 voxel sizes, 0.125 and 0.25 mm. The images were evaluated by 3 oral radiologists. Indices of sensitivity, specificity, and positive and negative predictive values, in addition to the areas under the receiver operating characteristic curves (accuracy), were calculated. Comparison of the accuracy of the imaging methods was assessed by using the χ2 test. Comparison of the accuracy between teeth with and without posts was determined by using the Fisher exact test.Results
The accuracy of the imaging methods showed no significant differences (P = .08). The comparison between teeth with and without posts in each examination revealed significant differences for CBCT with a voxel of 0.125 mm (P = .04) and for periapical radiography (P = .04).Conclusions
No significant differences were observed between CBCT and periapical radiography in the detection of vertical root fractures, except for teeth with metallic posts in images from CBCT with a voxel of 0.125 mm and in digital periapical radiography. Furthermore, voxel size did not significantly influence the diagnosis of vertical root fractures. 相似文献55.
de Oliveira Diniz CK Corrêa MG Casati MZ Nociti FH Ruiz KG Bovi Ambrosano GM Sallum EA 《Journal of periodontology》2012,83(10):1297-1303
Background: Diabetes mellitus (DM) involves metabolic changes that can negatively influence periodontal tissues, resulting in more prevalent and severe periodontitis and impaired bone formation. Occlusal trauma (OT) is an injury of the supportive periodontium that results in bone loss. It can be hypothesized that DM would increase bone loss after OT, mainly when associated with periodontitis. Thus, the aim of the present study is to evaluate the influence of DM on bone response in the furcation area of teeth subjected to OT in the presence, or absence, of experimental periodontitis (EP) in the rat model. Methods: Thirty-two male Wistar rats were assigned to four groups: 1) group 1 (G1): DM+OT+EP (n = 8); 2) group 2 (G2): DM+OT (n = 8); 3) group 3 (G3): OT+EP (n = 8); and 4) group 4 (G4): OT (n = 8). G1 and G2 received a single intraperitoneal injection of streptozotocin (STZ). After 10 days, G1 and G3 were subjected to EP by ligature placement. Fifteen days after the start of EP, OT was induced by the creation of a premature contact. The animals were euthanized 35 days after DM induction. Results: DM enhanced bone loss in the presence of OT combined with EP, but did not increase bone loss in teeth subjected to OT alone. EP caused greater bone loss when associated with OT. Conclusion: Within the limits of this animal study, it can be concluded that DM enhances bone loss in the presence of occlusal trauma associated with EP. 相似文献
56.
Ozelia Sousa-Santos Evandro M. Neto-Neves Karina C. Ferraz Jonas T. Sertório Rafael L. Portella Jose E. Tanus-Santos 《Thrombosis research》2013
Introduction
Acute pulmonary thromboembolism (APT) is a critical condition associated with acute pulmonary hypertension. Recent studies suggest that oxidative stress and hemolysis contribute to APT-induced pulmonary hypertension, possibly as a result of increased nitric oxide (NO) consumption. We hypothesized that the antioxidant tempol could attenuate APT-induced hemolysis, and therefore attenuate APT-induced increases in plasma NO consumption.Materials and Methods
APT was induced in anesthetized sheep with autologous blood clots. The hemodynamic effects of tempol infused at 1.0 mg/kg/min 30 min after APT were determined. Hemodynamic measurements were carried out every 15 min. To assess oxidative stress, serum 8-isoprostanes levels were measured by ELISA. Plasma cell-free hemoglobin concentrations and NO consumption by plasma samples were determined. An in vitro oxidative AAPH-induced hemolysis assay was used to further validate the in vivo effects of tempol.Results
APT caused pulmonary hypertension, and increased pulmonary vascular resistance in proportion with the increases in 8-isoprostanes, plasma cell-free hemoglobin concentrations, and NO consumption by plasma (all P < 0.05). Tempol attenuated the hemodynamic alterations by approximately 15-20% and blunted APT-induced increases in 8-isoprostanes, in cell-free hemoglobin concentrations, and the increases in NO consumption by plasma (P < 0.05). Tempol dose-dependently attenuated AAPH-induced in vitro hemolysis (P < 0.05).Conclusions
Our findings are consistent with the idea that antioxidant properties of tempol decrease APT-induced hemolysis and nitric oxide consumption, thus attenuating APT-induced pulmonary hypertension. 相似文献57.
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