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1.
Dr. Barry Pass John E. Aldrich Patricia L. Scallion 《Calcified tissue international》1990,46(3):166-168
Summary The ESR spectra produced in irradiated dentin have been studied over a range of incident radiation energies from 50 kVp to
25 MVp. The behavior of the dentin ESR signal strength is similar to that of enamel as a function of the energy of the incident
radiation. The magnitude of the dentin ESR signals are, however, up to 10 times smaller than the signals of dental enamel
for a given radiation energy. The possible contributions of radiation interaction coefficients, chemical structure, and crystallite
size to the differences in ESR spectra are discussed. 相似文献
2.
3.
Lasse Kanerva Maj-Len Henriks-Eckerman Tuula Estlander Riitta Jolanki Kyllikki Tarvainen 《Journal of the European Academy of Dermatology and Venereology》1994,3(2):157-168
Background Dentin-bonding systems contain sensitizing acrylates. They are increasingly used in dentistry, but only few cases of allergy have been encountered. Objective This study reports observations on eleven patients sensitized by acrylates in dentin-bonding compounds. Furthermore, the composition of dentin-bonding products was analysed and compared with the information given in the material safety data sheets. Methods Patch testing was performed to reveal allergic contact dermatitis, and chamber provocation tests to reveal possible respiratory sensitivity. Gas chromatography/mass spectrometry was used to analyse the chemical composition of the bonding products. Results The most common sensitizer in our material of eleven patients was 2-hydroxyethyl methacrylate (2-HEMA). Another putative sensitizer, BIS-GMA, used in dentin adhesives, did not cause sensitization. The typical allergic dermatitis localized to the fingertips (pulpitis). Seven of the eleven patients also developed paresthesia of the fingertips. One patient with positive patch test reactions to (meth)acrylates had pharyngitis hut no skin symptoms. One patient was sensitized because she had been patch tested with too high a concentration (undiluted) of dentin-bonding components. Material safety sheets gave inaccurate or wrong information about the contents. Conclusion Dentin-bonding acrylates are strong sensitizers, and even a single exposure may sensitize. 相似文献
4.
S. Ritz R. Stock H. W. Schütz H. -J. Kaatsch 《International journal of legal medicine》1995,108(3):135-139
Determination of age at death on the basis of aspartic acid racemization in dentin is one of the most reproducible and accurate methods. In Germany, age estimation by this method has so far generally not been applied to living persons, since the extraction of a tooth exclusively for age estimation when it is not medically indicated is regarded as ethically and legally problematic. The development of a biopsy technique applicable to dentin took place against this background. Testing the technique and analysis of dentinal biopsy specimens revealed that the biopsy technique is a low-risk procedure that causes only minor discomfort to the affected person. It is readily practicable and facilitates standardized specimen removal. The relationship between the extent of aspartic acid racemization in dentinal biopsy specimens and age is very close, facilitating age estimation. A prerequisite for accurate results is the performance of biopsies under strictly standardized conditions. If this is guaranteed, age determination on the basis of aspartic acid racemization in dentinal biopsy specimens appears to be superior in precision to most other methods in living persons and can be used for all age groups. 相似文献
5.
目的 :为探索治疗牙本质过敏症的新疗法 ,观察激光治疗后过敏齿的临床疗效 .方法 :应用 Nd:YAG激光点射治疗过敏齿 152 1颗 ,其中 °过敏 10 17颗 , °过敏 50 4颗 .结果 :即刻有效率为98.6 8% ;经 3~ 12个月的临床观察 , °过敏痊愈 814颗 (80 .0 4 % ) ,显效 183颗 (17.99% ) ,有效率为98.0 3% ; °过敏痊愈 119颗 (2 3.6 1% ) ,显效 339颗 (6 7.2 6 % ) .结论 :两组总有效率为 95.6 6 %。操作简便 ,无痛苦 ,是一种快速有效的方法 相似文献
6.
报告1例鼻咽癌颈淋巴结转移致颈动脉窦过敏综合征和1例全喉切除加颈淋巴结清扫术术后瘢痕形成出现颈动脉窦过敏综合征。对耳鼻咽喉科相关疾病引起的颈部肿块和瘢痕病变压迫颈动脉窦所致颈动脉窦过敏综合征的致病原因、临床表现及诊断、治疗原则进行了讨论。此类患者在临床上少见,易误诊,应引起重视。 相似文献
7.
Summary Magnesium (Mg) is a conspicuous constituent of hard tissues but its possible role in biomineralization is poorly understood. It is possible that Mg2+ adsorbed onto bioapatites may contribute to the modulation of crystal growth as such inhibitory activity has been reported for synthetic apatites. The present study was undertaken to determine the adsorption isotherms of Mg ions onto synthetic apatites and biominerals in tooth and bone tissues in the presence of other ions of natural occurrence. Synthetic crystals used as adsorbents were hydroxyapatite and, as a better prototype for the biomineral, Mg-containing carbonatoapatite. Human enamel and dentin materials were obtained from extracted, caries-free, permanent teeth. Porcine dentin materials at two developmental stages were obtained from erupted deciduous and unerupted permanent teeth of a 6-month-old slaughtered piglet. Porcine bone was obtained from the cortical portion of the mandible of the same animal. All biomineral samples were pulverized and then treated by plasma ashing (deproteination) at about 60°C. Each of the powdered samples was equilibrated in solutions containing various initial concentrations of Mg2+, Ca2+, and Na+ (or K+) as nitrate salts. Following equilibration, concentrations (and activities) of magnesium and calcium ions in the experimental solution were determined. The pH values of the equilibrium solutions were in the range of 6.2–6.5. Experimental data of the Mg adsorption onto hydroxyapatite were interpreted on the basis of a Langmuir-type model for binary systems assuming competition of Mg2+ and Ca2+ for the same adsorption sites on the crystal surfaces of the apatites. According to this model, the adsorbed Mg is expressed as a function of the ionic activity ratio (Mg2+)/(Ca2+) in the equilibrium solution. The model contains two parameters, the adsorption selectivity constant Ks and the maximum number of adsorption sites N (mol/g). The numerical values of Ks were similar for all adsorbents used (synthetic and biological) and indicated the preferential adsorption of Ca2+ probably due to spacial restrictions extending to the very surface of the crystals. The initial level of Mg2+ in the surface pool was different in the various biominerals, probably reflecting the composition of fluid in which the biominerals were formed. Whereas the surface pool of Mg of human enamel was marginal, only 5% of the total Mg, significant fractions of the total Mg in human and porcine dentins (about 20–30%), and porcine bone (about 40%) existed on the crystal surfaces. There were significant differences in the total Mg and the value of the parameter N between young (unerupted) and mature (erupted) dentin minerals. It was ascertained that the occupancy of adsorption sites by Mg ions became greater with maturation of the dentin tissues. The overall results suggest that the Mg-mineral interaction in tooth and bone tissues may be a highly tissue-specific process, presumably reflecting differences in fluid composition (particularly Ca and Mg activities) responsible for biomineralization. 相似文献
8.
Dentin Sialoprotein (DSP) Has Limited Effects on In Vitro Apatite Formation and Growth 总被引:7,自引:0,他引:7
Sialoproteins such as bone sialoprotein (BSP) and dentin sialoprotein (DSP) accumulate at the mineralization fronts in bone
and dentin, respectively, suggesting they have some function in the mineralization process. BSP, a highly phosphorylated protein
rich in polyglutamate repeats, is an effective nucleator of hydroxyapatite (HA) formation in vitro. The present study examines the effect of DSP, a low phosphorylated but related sialoprotein, on the formation and growth
of HA. In vitro, in a gelatin gel diffusion system, DSP at low concentrations (<25 μg/ml) slightly increased the yield of HA formed at 3.5
and 5 days, while at higher concentrations (50–100 μg/ml) it slightly inhibited accumulation. Fewer mineral crystals were
formed in the presence of high concentrations of DSP but they tended to aggregate (making them appear larger by electron microscopic
analysis) than those formed in DSP-free gels. X-ray diffraction line broadening analysis failed to show significant changes
in c-axis crystal dimensions with increasing DSP concentration. When HA-seed crystals were coated with DSP before inclusion
in the gelatin gel there was a reduction in mineral accumulation relative to HA-seeds which had not been coated with DSP,
but the extent of inhibition was significantly less than that seen in this system with other mineralized tissue matrix sialoproteins,
such as osteopontin or BSP. The low affinity of DSP for well-characterized seed crystals and the limited effect of this protein
on HA formation and growth suggest that the role of DSP in dentin is not primarily that of a mineralization regulator.
Received: 25 April 2000 / Accepted: 21 July 2000 / Online publication: 2 November 2000 相似文献
9.
Kanako J. Nagatomo Kevin A. Tompkins Hanson Fong Hai Zhang Brian L. Foster Emily Y. Chu 《Connective tissue research》2013,54(6):391-400
Bone morphogenetic proteins (BMPs) and BMP antagonists play a crucial role in the regulation of tooth development. One of the BMP extracellular antagonists, gremlin, is a highly conserved 20.7-kDa glycoprotein. Previously, researchers reported that transgenic mice overexpressing gremlin under the control of the osteocalcin promoter (gremlin OE) exhibit a skeletal phenotype and tooth fragility. To further define the tooth phenotype, teeth and surrounding supporting tissues, obtained from gremlin OE at ages of 4 weeks, 2 months, and 4 months, were examined. The histological results demonstrate that gremlin OE exhibit an enlarged pulp chamber with ectopic calcification and thinner dentin and enamel compared with wild-type control. In vitro studies using murine pulp cells revealed that gremlin inhibited BMP-4 mediated induction of Dspp. These data provide evidence that balanced interactions between BMP agonists/antagonists are required for proper development of teeth and surrounding tissues. It is clear that these interactions require further investigation to better define the mechanisms controlling tooth root formation (pulp, dentin, cementum, and surrounding tissue) to provide the information needed to successfully regenerate these tissues. 相似文献
10.
《Dental materials》2021,37(8):1316-1324
ObjectivesThe purpose of the study was to evaluate the integrity of dentine type I collagen after self-etching (SE) treatments with strong and mild universal adhesives.MethodsCoronal dentine specimens (n = 10/product) were imaged by optical microscopy and analyzed by ATR-FTIR spectroscopy before and after treatment with 32% phosphoric acid gel (PA-negative control), 17% neutral EDTA (ED-positive control) conditioners and Adhese Universal (AD), Clearfil Universal Bond Quick (CQ), G-Premio Bond (GP), Prelude One (PR) and Scotchbond Universal (SB) adhesives. From the spectroscopic analysis the following parameters were determined: a) Extent of dentine demineralization (DM%) and b) percentage area of the Amide I curve-fitted components of β-turns, 310-helix/β-turns, α-helix, random coils, β-sheets and collagen maturation (R) index. Statistical analysis was performed by one-way ANOVA (DM%), paired t-test/Wilcoxon test (Amide I components) and Spearman correlation coefficient (DM% vs Amide I components) at an a = 0.05 level.ResultsPA, ED and GP removed the smear-layer and opened tubule orifices, whereas all other treatments removed only the intratubular smear-layer fraction. The ranking of the statistically significant differences in DM% was PA > GP > ED > AD, SB, CQ, PR, with AD being significantly different from PR. Regarding the Amide I components, PA demonstrated a significant reduction in β-turns, α-helices and an increase in β-sheets, GP a reduction in β-turns, AD an increase in β-turns and random coils, and CQ an increase in β-turns. PR, SB and ED showed insignificant differences in all the Amide I components. Significant correlations were found between DM%-random coils and DM%-R.SignificanceThe universal adhesives used in the SE mode induced none to minimal changes in dentine collagen structure, without evidence of the destabilization pattern observed after conventional phosphoric acid treatments. 相似文献