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《Dental materials》2022,38(10):1633-1647
ObjectivesAnalyzing factors that may have led to fracture of zirconia implants by macro/micro-fractography.MethodsSix one-piece and ten two-piece full-ceramic zirconia implants from two manufacturers, Z-Systems and CeraRoot, were retrieved after clinical failure. The time-to-failure ranged from 3 to 49 months. Optical and scanning electron microscopy (SEM) were used to analyze the fracture planes at the macro- and microscopic level. Treatment planning, surgical protocol, fracture-origin location and characteristic fracture features were assessed.ResultsThe fracture of all implants seemed to have been primarily due to overload in bending mode, while the fracture-initiation sites varied for the one- and two-piece implants. The fracture of all one-piece implants originated in the constriction region between two threads in the endosseous implant part. For two-piece implants, the abutment neck, internal abutment-implant connections and inner threads were found to be the main fracture-initiation sites. Surface defects at the root area for one-piece implants and damages at the abutment surface for two-piece implants were connected to the fracture origins. Importantly, the clinical failures of implants were often found to result from combined effects related to patient aspects, treatment planning/protocols, a high bending moment at the weakest link, implant-surface conditions and specific implant designs.SignificanceThis study provided information to be considered for future optimization of treatment planning and the surgical protocol for zirconia implants. Optimization of the surface conditions and the zirconia-starting powder were also suggested.  相似文献   
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ObjectiveThe goal of this study was to evaluate the quality of life of parents of children who use hearing aids (HA) with those who use cochlear implants (CI) in the Indian context and document any differences found.MethodsThe Kannada version of the AQoL-4D was administered in a modified fashion to 131 parents (87 HA and 44 CI). Sociodemographic details were collected for supplemental information on the intervention strategy used.ResultsA total of 49 parents (29 HA and 20 CI) responded to the questionnaire sent. The mean total scores for both the groups were similar (HA group = 17.9 (SD = 5.5), CI group = 17.2 (SD = 3.4)), as was the score for the first subscale (HA group = 8.6 (SD = 2.9); CI group = 8.5 (SD = 2.6)) of the AQoL-4D. No significant differences were found between the two groups on either scores [Total Score: U (NHA = 29, NCI = 20) = 280.5, z = ?0.194, p > 0.05; Subscale 1 Score: U (NHA = 29, NCI = 20) = 281.5, z = ?0.176, p > 0.05]. The degree of hearing loss in the hearing aid group was equivalent to that of the cochlear implant group but this did not appear to influence parental quality of life.ConclusionParents of children with hearing aids and cochlear implants appear to be similar on several psychosocial factors in the realms of functional, social, and psychological well-being. In terms of parental quality of life, hearing aids and cochlear implants appear to be equally effective intervention techniques.  相似文献   
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The aim of this study is to compare the accuracy of maxilla positioning in orthognathic surgery with the use of custom-made devices (cutting guides and patient-fitted osteosynthesis plates) comparing to CAD/CAM splints.A prospective randomized study was performed. Patients with dentofacial deformities undergoing orthognathic surgery were compared, using customized guides (experimental group) vs. CAD/CAM surgical splints (control group) for the repositioning of the upper maxilla. Preoperative and postoperative CT scans were used to compare positioning and fixation of the maxilla in the three planes of space.A total of 30 patients were included in the study (15 patients in each study group). The mean error obtained with customized guides was 0.8 mm (range 0.1–1.9) in the anterior-posterior axis, 0.4 mm (range 0–1.4) in the vertical axis and 0.2 mm (range 0–1.1) in the horizontal axis. There were statistically significant differences in the anterior-posterior and vertical axes in favour of the customized implants, whereas there were no differences in the horizontal plane. Furthermore, there was a mean reduction of the operative time of 36.5 min in the experimental group.Within the limitations of the study it seems that patient specific surgical guides should be preferred when accuracy of repositioning of the maxilla and saving operative time are the priority.  相似文献   
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《Dental materials》2022,38(6):924-934
ObjectivesTo study the oxide layer stability of certified dental implants of system "P", made based on TiO2 alloy with carbon coating. To perform a comparative statistical analysis of the obtained data with the available data for the dental implants of systems "A" and "B".MethodsX-ray microtomography and X-ray fluorescence analysis were used to study soft tissue biopsy specimens. Supernatants were studied by dynamic light scattering and transmission electron microscopy when simulating free emission of nanoscale metal oxide particles from the surface of dental implants as well as when simulating physical loading. A comparative analysis of three parameters of nanoscale particles was performed by statistical data analysis. The surface of the "P" system dental implant with surface treatment was analyzed by scanning electron microscopy.ResultsBoth free emission of nanoscale oxide layer particles and yield of nano- and microscale particles during simulation of physical load were confirmed. Statistically significant differences were noted in a comparative analysis of the size and frequency of occurrence of these particles in the supernatants obtained from the surfaces of three dental implant systems. The elemental composition of the particles and the composition and structure of the "P" system dental implants themselves were analyzed.SignificanceThe developed method of dynamic light scattering can be used to compare the stability of the oxide layer of standardized medical products manufactured on the basis of the TiO2 alloy.  相似文献   
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目的:利用X线片观察并测量后牙区即刻种植术后的牙槽骨改变,比较即刻种植与延期种植术后牙槽骨吸收的程度。方法:对我院2014—2016年间后牙区94例即刻种植义齿和168例延期种植义齿进行术后6个月及1年随访,患者种植术后即刻、术后6个月和术后1年复查时均采用平行投照技术拍摄X线片,利用测量软件测量种植体近中及远中牙槽嵴顶端与种植体颈部之间的垂直距离。采用SPSS 19.0软件包进行配对t检验,分析即刻、术后6个月以及1年时种植体近远中牙槽骨的吸收变化。结果:无论即刻种植还是延期种植组,所有植体都获得了良好的骨结合。在种植体植入后,近远中的牙槽骨均有不同程度吸收。术后6个月复查时,即刻种植组牙槽骨近远中平均吸收0.25 mm,延期种植组牙槽骨近远中平均吸收0.43 mm,差异无统计学意义(P>0.05)。术后1年复查时,即刻种植组牙槽骨近远中平均吸收0.57 mm,延期种植组牙槽骨近远中平均吸收1.10 mm,差异有统计学意义(P<0.05)。结论:后牙区即刻种植和延期种植术后,植体均可获得良好的骨结合;术后近远中方向牙槽骨均发生明显吸收,且术后1年时即刻种植组牙槽骨吸收程度轻于延迟种植组。  相似文献   
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The aim of this systematic review was to test the following hypotheses: (1) that there is no difference in implant survival rate between individuals with overweight or obesity and those who are within the ideal weight range; (2) that there are no differences between these groups regarding indicators of peri-implant health. Two independent reviewers performed a literature search of the PubMed/MEDLINE, Scopus, and Cochrane Library databases for studies published up to April 1, 2018. A meta-analysis was performed to determine the risk difference for implant failure and mean difference for marginal bone loss, probing depth, and bleeding on probing. Six studies were selected for review, involving a total of 746 patients with 986 implants: 609 in overweight or obese individuals and 377 in individuals within the ideal weight range. The findings of this systematic review indicate that the first hypothesis should be accepted, since no statistically significant difference in implant survival rate was found between individuals with overweight/obesity and those within the ideal weight range (P = 0.64). The second hypothesis was rejected, as the review indicated a difference in marginal bone loss (P < 0.00001), probing depth (P < 0.00001), and bleeding around dental implants (P < 0.00001).  相似文献   
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