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51.
52.
J. MICHAEL McGUIRE 《Journal of Urban Affairs》1990,12(2):103-119
ABSTRACT: St. Louis is one of many U.S. cities suffering from urban decay and fiscal crisis. To resolve these problems, the city has adopted a redevelopment program under Missouri State Statute 353. This Chapter 353 program grants private developers 25 years of tax abatement for making property improvements and permits them to accumulate property through the exercise of eminent domain. The program includes the city's entire central business district and has been extended to cover residential areas. This article discusses the research study on which this Chapter 353 program was based, points out a number of serious problems, and concludes that the program may, in fact, further reduce the city's fiscal integrity. 相似文献
53.
APPLICATION OF AN IN-LINE RHEOLOGICAL CHARACTERIZATION METHOD TO CHEMICALLY MODIFIED AND NATIVE CORN STARCH 总被引:1,自引:0,他引:1
The application of an in‐line ultrasonics‐based rheological characterization method for measuring the rheological properties of 6% (w/v) acid‐thinned and native corn starch suspensions and gels was studied. The measurements were performed in steady, laminar pipe flow using a 5 MHz frequency transducer to determine the radial shear rate distribution. Two pressure transducers were used to measure the pressure drop allowing the shear stress distribution to be calculated through the conservation of linear momentum. It was possible to obtain shear viscosity over a range of shear rates, 1–50 1/s, from a single velocity profile. A comparison of the shear viscosity function at different flow rates showed that this method could be a valid method of process rheometry during the manufacturing of starch‐based products. Both ultrasonics and rotational rheometry results showed that acid‐thinned and native corn starch suspensions exhibited Newtonian behavior before heat treatment and non‐Newtonian behavior after heating. Power law consistency index and flow behavior index of the acid‐thinned corn starch gel at 39°C were 0.60 Pa.s 0.68 and 0.68, respectively; whereas those of the native corn starch were 5.90 Pa.s 0.37 and 0.37 at 38C. Their consistency index increased and flow behavior index decreased with cooling and a thermoreversible change in the flow behavior index was observed in the native corn starch after storage. 相似文献
54.
An appreciable percentage of electric power is generated by oil-fired power plants. The ash resulting from such plants is typically very high in elements such as vanadium, nickel, aluminum and molybdenum. Oil bottom ash and fly ash when disposed or fly ash fallout from such power plants could result in absorption of such metals by agricultural crops. Swiss chard (Beta vulgaris L.) was grown in potted soils amended with oil bottom ash and fly ash at 2% and 1% (w/w), respectively. The crop absorbed significantly higher concentrations of each of the metals as compared to those in the control crop grown on soil alone. Higher levels of the ashes in soil resulted in phytotoxicity to the swiss chard . 相似文献
55.
Extracts of aromatic plants contain bioactive substances such as phenolic compounds, which could be used as natural antioxidants. Conventional, as well as ultrasonically assisted extractions (UAEs ) of phenolic compounds from aromatic plants using different solvents, have been studied. Reversed phase high performance liquid chromatography (RP‐HPLC ) with ultraviolet detection was employed for the analysis of phenolic compounds. Total phenolic compounds were determined by the Folin–Ciocalteu assay. The amount of extractable phenolic substances for this method decreased with decreasing polarity of the solvent in the order water, 60% methanol, 60% acetone, and ethyl acetate/water (60:30, v/v). The HPLC results indicate that UAE is a more effective technic compared to the conventional method but was dependent on the solvent and the temperature employed. Increasing the temperature of sonication, the efficiency of extraction of phenolic compounds for all solvents is enhanced. However, water extraction was found to give reduced amounts of phenolic compounds when compared with the conventional method. 相似文献
56.
One kind of prosodic structure that apparently underlies both music and some examples of speech production is meter. Yet detailed measurements of the timing of both music and speech show that the nested periodicities that define metrical structure can be quite noisy in time. What kind of system could produce or perceive such variable metrical timing patterns? And what would it take to be able to store and reproduce particular metrical patterns from long-term memory? We have developed a network of coupled oscillators that both produces and perceives patterns of pulses that conform to particular meters. In addition, beginning with an initial state with no biases, it can learn to prefer the particular meter that it has been previously exposed to. 相似文献
57.
58.
MICHAEL J. MILLER 《Computer-Aided Civil and Infrastructure Engineering》1986,1(3):233-245
Placing text on the graphics screen in any size any angle is an important function of a graphics program. Some microcomputers, however, will not print characters on the graphics screen, and others have very limited ability, such as printing only in 40-character or 80-character mode. Characters are needed for dimensions and notes on the drawing as well as for prompts and messages. Alternate fonts, rotation of the text, and different sizes of text are needed for many applications, not to mention text that is scaled up and down as the user zooms in or out to magnify or reduce the size of the image. This article examines available techniques and discusses the advantages and disadvantages of each. A method is presented for producing stroke generated text by designing each character as a matrix of dots on a standard grid and storing the coordinates of the dots as endpoints of vectors to be used to draw the character. The standard grid is assumed to have its origin in the lower left corner and each coordinate is defined relative to that origin. 相似文献
59.
This article clarifies key concepts that undergird qualitative research, which is being used increasingly as engineering educators improve classrooms, programs, and institutions. The paper compares quantitative and qualitative research, describes some qualitative data collection strategies used in engineering education, addresses methods for establishing trustworthiness, and discusses strategies for analyzing qualitative data. Also included are illustrative examples of recent engineering education research that features qualitative data analysis and mixed‐method (quantitative and qualitative) approaches. 相似文献
60.
Six cheese varieties encompassing a wide compositional and age range were analyzed fresh and after aging to determine correlations between casein proteolysis products, fat content, moisture content, and torsion results. Shear stress, a measure of the strength of the casein matrix, was dependent on the amount of intact αsl‐casein. Shear strain, a measure of the cohesiveness of a structure, exhibited a negative correlation with fat content and a positive correlation with moisture content. Shear strain was also correlated with the ratio of moisture to protein, an indication of the interaction between casein particles. Torsion tests provide information on the level of degradation of the casein network in cheese, which can be used by manufacturers to alter storage conditions to optimize the quality of their aged cheese., April 10, 2003 相似文献