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排序方式: 共有268条查询结果,搜索用时 31 毫秒
71.
Evaluation of Italian wine by the electronic tongue: recognition, quantitative analysis and correlation with human sensory perception 总被引:2,自引:0,他引:2
The electronic tongue based on a sensor array comprising 23 potentiometric cross-sensitive chemical sensors and pattern recognition and multivariate calibration data processing tools was applied to the analysis of Italian red wines. The measurements were made in 20 samples of Barbera d’Asti and in 36 samples of Gutturnio wine. The electronic tongue distinguished all wine samples of the same denomination and vintage, but from different vineyards. Simultaneously the following quantitative parameters of the wines were measured by the electronic tongue with precision within 12%: total and volatile acidity, pH, ethanol content, contents of tartaric acid, sulphur dioxide, total polyphenols, glycerol, etc. The electronic tongue is sensitive to multiple substances that determine taste and flavour of wine and, hence, the system was capable of predicting human sensory scores with average precision of 13% for Barbera d’Asti wines and 8% for Gutturnio wines. 相似文献
72.
Alexei N. Pankratov Inna M. Uchaeva 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):791-802
By the PM3 method, standard values of entropy, heats and Gibbs energies of formation and dipole moments of the molecules have been computed for a series of inorganic and organic antimony compounds. Linear dependences P exper = bP theor (where P is any of the mentioned properties) have been stated, allowing a priori evaluation of thermodynamic characteristics and molecular dipole moments of Sb-containing substances. It has been concluded that triphenylstibinedichloride in benzene solution, as well as triphenylstibinehydroxychloride in dioxane medium, exist in the form of trigonal bipyramid with two axial chlorine and oxygen atoms. 相似文献
73.
A new test method and instrument was developed to provide overall evaluation and characterisation of touch properties of porous polymeric materials. The test method and instrument can simulate the dynamic contact process between human skin and porous polymeric materials and obtain the mechanical and physical performance during contact. In the improved test method, a new measurement principle was proposed, and the mechanical device was redesigned, including surface friction measurement components. Most indices were redefined and the grading and classification methods were studied to give a direct overall evaluation of the touch properties for industrial applications. The objective test results and analysis, subjective evaluation method and prediction model of touch properties are also presented. The improved test method provides an objective measurement of thermal-mechanical properties using a single measuring instrument for new product development and quality control of porous polymeric materials. 相似文献
75.
黄土边坡剥落病害的发育特征及其发育程度评价 总被引:2,自引:0,他引:2
黄土边坡剥落病害影响黄土边坡的坡面稳定及环保美观。以黄延高速公路黄土路堑边坡剥落病害为背景,采用现场调查结合理论分析的方法,研究了黄土边坡剥落病害的发育特征; 将发育特征与可拓工程方法相结合,实现了黄土边坡剥落病害发育程度的评价。研究结果表明:(1)黄土中节理裂隙分布密度大于6条 ·m-1 时,极易发生剥落,小于2条 ·m-1 时,基本不发生剥落。黏粒含量大于15%时,剥落病害越易发生,小于5%时,不易发生剥落。黄土边坡开挖量越大、剥落产生的厚度越大。黄土边坡坡体节理裂隙促使剥落病害的发生。当黄土边坡单级坡高大于10m、坡度大于60°时,容易出现重力型剥落病害; 而单极坡高小于4m、坡度小于50°时,边坡坡面很少出现剥落病害。(2)针对影响黄土边坡剥落病害发育因素的复杂性和模糊性,重视实践中的经验,将可拓工程方法与黄土边坡剥落发育程度评价相结合,提出了黄土边坡剥落发育程度的物元关联函数及物元关联度的计算方法。建立了适合可拓学理论的黄土边坡剥落发育程度的分类标准,实现了定性与定量评价结合。 相似文献
76.
分析测试不确定度的评定与表示(Ⅰ) 总被引:14,自引:0,他引:14
就“不确定度”概念的来历和意义;基本术语;误差与不确定度;化学分析测量不确定度的来源;不确定度的评定;标准物质的不确定度;不确定度的评定实例等7个方面概述分析测试不确定度的评定与表示,介绍不确定度的基本知识与应用。 相似文献
77.
顾客满意度测评的模糊集合论模型 总被引:8,自引:0,他引:8
基于国际通用的顾客满意度测评的计量经济学模型,应用模糊综合评判和模糊推理建立顾客满意度测评的模糊集合论模型,介绍“五一黄金周”旅游市场顾客满意度测评的实证研究。 相似文献
78.
Three novel adhesive oligomers having carboxylic acid and methacrylate groups were synthesized, characterized and used to formulate composite bone cements with newly synthesized zinc-calcium-silicate phosphate. The optimal formulation was determined based on types of oligomer, oligomer/diluent ratio, initiator concentration, and filler level using compressive strength (CS) and curing time (CT) as screening tools. Shrinkage, exotherm and aging of the formed composite cements were also evaluated. Results show that the experimental cement was 186% higher in CS, 16% higher in diametral tensile strength, similar in flexural strength, 56% less in exotherm and 64% less in shrinkage, as compared to conventional polymethylmethacrylate cement. The optimal concentrations for initiators were found to be 1.5% (by weight) for both benzoyl peroxide and N,N′-dimethyl-p-toluidine. With increasing initiator concentration, diluent content and zinc oxide content in the cement formulation, CS of the cement increased but curing time decreased. Shrinkage and exotherm of the cement decreased with increasing filler level. CS was not proportional to an increase of filler level and CT increased with an increase of filler level. During aging, the cement showed an increase of strength over 24 h and then no change for over nine months. It appears that this novel cement may be a potential candidate for orthopedic restoration if its biological performance is good and the formulation is optimized. 相似文献
79.
We investigate an ellipsoid algorithm for nonlinear programming. After describing the basic steps of the algorithm, we discuss
its computer implementation and present a method for measuring computational efficiency. The computational results obtained
from experimenting with the algorithm are discussed and the algorithm's performance is compared with that of a widely used
commercial code.
This research was supported in part by The National Science Foundation, Grant No. MCS78-02096. 相似文献
80.
Summary The CASE (Computer Automated Structure Evaluation) program, with the aid of a geometry index for discriminating cis and trans isomers, has been used to study a set of retinoids tested for teratogenicity in hamsters. CASE identified 8 fragments, the most important representing the non-polar terminus of a retinoid with an additional ring system which introduces some rigidity in the isoprenoid side chain. The geometry index helped to identify relevant fragments with an all-trans configuration and to distinguish them from irrelevant fragments with other configurations. 相似文献