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991.
The purpose of this project was to evaluate practice type and geographical differences in methods of payment accepted for children's dental services. A survey was mailed to 2000 general dentists and 1000 pediatric dentists randomly selected to provide representation from the 50 United States. Dentists were asked to specify the type of practice and the state in which they primarily practice. The survey included Medicaid, dental insurance, preferred provider organizations (PPO), and self-payment as payment options. Dentists were asked to indicate whether they never, occasionally, or frequently accepted each option of payment for children's dental services. Responses were received from 1245 (42%) dentists, including 723 general dentists and 522 pediatric dentists. Chi-square statistical analysis revealed significant practice type and regional differences in the acceptance of Medicaid for payment. Pediatric dentists accept Medicaid more frequently than general dentists (P < 0.001). Most dentists accept dental insurance and self-payment, while few indicate involvement with a PPO. The study revealed significant practice type differences only in the acceptance of Medicaid as payment for children's dental services. On a geographic basis, there were significant differences in the acceptance of Medicaid and dental insurance.  相似文献   
992.
Human ameloblastoma tumors express the amelogenin gene.   总被引:1,自引:0,他引:1  
Instructive signals are responsible for the regulation of the expression of gene products characteristic of many cell lineages during normal development and potentially during neoplasia. The odontogenic origin of ameloblastomas is based largely on the similarity in histologic appearance between the tumor and the developing tooth organ. A pathognomonic pattern for odontogenic tissue-specific gene expression in ameloblastomas has not been previously shown. In these studies, the gene expression parameters for human ameloblastomas have been characterized with the techniques of messenger RNA phenotyping in combination with Northern and in situ hybridization analysis of messenger RNA. The results of these studies confirm that amelogenin, a gene transcribed solely by differentiated ameloblasts, was expressed by epithelial cells from human ameloblastomas. This observation suggests that the instructive signals required for ameloblast differentiation are shared during normal development and tumorigenesis of odontogenic epithelium.  相似文献   
993.
A bovine tooth model system was used to study the effect of experimental salivary pellicle on enamel erosion. Test blocks with varnish-covered control surfaces in each specimen were immersed into an acidic cola beverage (pH 2.6) for 120 min, either with or without the pellicle which was grown for 7 days by using clarified human saliva. After immersion, the pellicle was removed from some specimens with 10% sodium hypochlorite (20 h at 20 degrees C) and ultrasonic bath (60 s) to study its effect on erosion. All specimens were then studied in the scanning electron microscope. The specimens without pellicle (positive controls) showed gross erosion with prism core dissolution in all study blocks. The specimens with pellicle showed occasionally a film-like integument covering the apparently intact test surfaces with adjacent enamel surfaces slightly eroded. The erosion, however, was not of the same magnitude as in the positive controls. After removing the pellicle, the enamel surfaces showed pitted appearance of the prism heads; the demineralization seemed to attack more the prism sheath areas. Thus, salivary pellicle was found to protect the underlining enamel from erosion in vitro.  相似文献   
994.
Certain metal ceramic alloys alter the final color of bonded porcelain. Contradicting results, inconsistent test designs, and incomplete alloy selections have led to some confusion. In this study, differential colorimetric analysis was done at the opaque and dentin porcelain stages with five major types of metal ceramic alloys. The color stability of the porcelain on the high-noble metal alloys was found to be excellent. The palladium-silver and nickel-chromium alloys resulted in significant color changes of the dentin porcelain only. The greatest changes in color were found with the palladium-silver alloy, which resulted in a higher yellow-green saturation. The nickel-chromium alloy also produced a color change, although not as severe, resulting in a porcelain shade with a reduced Value or lightness.  相似文献   
995.
We evaluated three shades of nine light-cured composites to determine the colorimetric changes which occur as a result of the photo-polymerization reaction. A photo-electric tristimulus colorimeter was used to measure the color of a 0.5-mm-thick sample of composite on two different backgrounds before and after the polymerization process had been initiated. The results showed that each of the photo-initiated composites tested produced a visually significant change in color as a result of the polymerization reaction, regardless of the shade of the backing. In general, the light-cured composites produced a characteristic chromatic shift toward the blue region of color space, which resulted in a perceived decrease in yellow chroma. Therefore, direct shade selection of a resin composite which is more yellow or more chromatic than the tooth which is being restored is recommended to compensate for this characteristic immediate color shift.  相似文献   
996.
Type 2 diabetes mellitus and periodontal disease   总被引:3,自引:0,他引:3  
The relationship between type 2 diabetes mellitus and periodontal disease was evaluated in 2,878 Pima Indians of the southwestern United States. Two independent measures of periodontal disease, probing attachment loss and radiographic bone loss, were used to compare prevalence and severity of periodontal disease in diabetic and nondiabetic subjects. In all age groups studied, subjects with diabetes had a higher prevalence of periodontal disease, indicating that diabetes may be a risk factor for periodontal disease.  相似文献   
997.
The purpose of this study was to find out the factors influenced on the survival of amalgam dental restoration. The study population was the amalgam restoration of 726 molar teeth, 3 restoration types, cavity class I, class I other surface and class I compound, of Bangkok Metropolitan school children aged 6-12 years. The data showed how the survival of restoration placed in teeth varied with the restoration aged ranging 6-30 months. The result indicated that there were 48.10% of broken filling and 19.42% of secondary caries. The rate of broken filling was significantly related to the child age at the time of treatment, the restoration age, the surface texture of the restoration and the restoration type (p less than 0.01). As for the rate of secondary caries, there were significant correlation with the surface texture of the filling, the restoration type and the factor "broken filling" (p less than 0.01). By means of the linear multiple regression, it told us explicitly about the magnitude of the relation that the surface texture of the filling was the major influential factor which could predict the variance of broken filling about 18.29% while the broken filling was also the major influential factor which could predict the variance of secondary caries about 7.93%.  相似文献   
998.
Providers' periodontal diagnostic and treatment behaviors were assessed in 34 practices in two North Carolina counties. Regularly attending patients had a low prevalence of gingival pocketing on index teeth, moderate attachment loss, and fairly prevalent bleeding and calculus. Treatment frequency and patient knowledge were generally adequate, but the notation of periodontal status in the patient record was insufficient. A continuing education intervention resulted in substantial and significant improvement in notation rates. Changes in rates with which services were provided, and changes in patient periodontal status were smaller and mixed. The study shows that continuing education can be effective in helping some but not all providers adopt needed, appropriate behaviors.  相似文献   
999.
1000.
The non-human primate Macaca nemestrina was evaluated for use as a potential model in periodontal research by study of 16 animals. Using one incisor, premolar, and molar per quadrant, we measured supragingival plaque, severity of gingival inflammation, and pocket depth, and analyzed the subgingival flora. Serum IgG titers and avidities to antigens of Porphyromonas gingivalis (Pg) and Actinobacillus actinomycetemcomitans (Aa) were also assessed. Ten animals were between 13 and 24 years old, and six were between 4 and 5 years old. While mean gingival inflammation scores were significantly higher for older than for for younger animals (2.2 vs 1.8, p < 0.05), mean plaque index scores and mean probing depths did not differ significantly. The animals harbored a subgingival microflora considered to be pathogenic for humans including Aa, Pg, Bacteroides forsythus, Prevotella intermedia I and II, Campylobacter recta and Fusobacterium nucleatum . Aa, however, was found only in the younger animals. All of the animals had serum IgG antibodies reactive with antigens of Pg and Aa, and titers for Pg but not for Aa were significantly higher in the older relative to the younger animals (t test p < 0.02). In contrast, antibody avidity did not significantly differ between the two groups. A combined clinical assessment index based on maximum probing depth, gingival index score, and tooth loss was used to assess the overall disease severity. Titers were positively associated with disease severity (Spearman's rank correlation 0.57, p=0.02). We conclude that M. nemestrina harbors a subgingival microflora considered to be pathogenic for humans, manifest serum IgG antibodies to antigens of Pg and Aa, and exhibits clinical features of periodontitis comparable to those seen in humans. This species appears, therefore, to be a useful model for investigating periodontal microbial-host interactions, including the immune response.  相似文献   
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