全文获取类型
收费全文 | 235篇 |
免费 | 6篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 2篇 |
化学工业 | 9篇 |
金属工艺 | 12篇 |
机械仪表 | 23篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 2篇 |
轻工业 | 94篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 12篇 |
一般工业技术 | 25篇 |
冶金工业 | 2篇 |
原子能技术 | 8篇 |
自动化技术 | 40篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 10篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 54篇 |
2012年 | 6篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 5篇 |
2006年 | 10篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2001年 | 3篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 7篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1948年 | 1篇 |
排序方式: 共有243条查询结果,搜索用时 0 毫秒
41.
Abstract. Oranges and grapefruit were subjected to single and repeated impact drops from three heights. Subsequent measurements of the force-deformation ratio and hysteresis loss were made with quasi-static compression tests on the impacted whole fruit. Internal damage was indicated by a reduction in the force-deformation ratio and an increase in the hysteresis loss for a single 100 cm drop and two or more drops from 25 or 50 cm heights. 相似文献
42.
MADELEINE BONNET AHMED OUALI JEAN KOPP 《International Journal of Food Science & Technology》1992,27(4):399-408
Osmotic pressure, an important physiological characteristic of plant and animal tissues, is difficult to measure, and no convenient and efficient method is so far available. In the present work we developed a differential scanning calorimetry (DSC) method, and estimated the physiological osmotic pressure of intact bovine muscle and post-mortem variation during the conversion of muscle into meat. We also examined the major role of sample pH in this variation. This method, based on the determination of the melting onset point of frozen muscle's indigenous water, was compared to a freezing point osmometric method and a soaking method. It was concluded that the DSC method appeared more practical and reliable than other methods and could be applied to various animal and plant tissues and fluids. 相似文献
43.
44.
A. A. AHMED T. M. El-SHAMY N. A. SHARAF 《Journal of the American Ceramic Society》1980,63(9-10):537-542
Simple binary alkali borate glasses of differing alkali content (alkali = Li, Na, or K) containing sulfur were prepared and their absorption spectra were measured in the range of 200 to 700 nm. The absorption bands obtained were used to determine the stable states of sulfur in these glasses by directly comparing them with published data. The following states of sulfur were identified and their ranges of stability were determined: the S2 molecule in glasses containing at least 15 mol% alkali oxide, the S3 − and S2 − in glasses containing 20 to 30 mol% Na2 O or K2 O, and the polysulfide ion (S x 2− ) in glasses of 30 to 35 mol% Na2 O or K2 O. 相似文献
45.
Adnan AHMED Kamalrulnizam ABU BAKAR Muhammad Ibrahim CHANNA Khalid HASEEB Abdul Waheed KHAN 《Frontiers of Computer Science》2015,9(2):280
Mobile ad-hoc networks (MANETs) and wireless sensor networks (WSNs) have gained remarkable appreciation and technological development over the last few years. Despite ease of deployment, tremendous applications and significant advantages, security has always been a challenging issue due to the nature of environments in which nodes operate. Nodes’ physical capture, malicious or selfish behavior cannot be detected by traditional security schemes. Trust and reputation based approaches have gained global recognition in providing additional means of security for decision making in sensor and ad-hoc networks. This paper provides an extensive literature review of trust and reputation based models both in sensor and ad-hoc networks. Based on the mechanism of trust establishment, we categorize the stateof-the-art into two groups namely node-centric trust models and system-centric trust models. Based on trust evidence, initialization, computation, propagation and weight assignments, we evaluate the efficacy of the existing schemes. Finally, we conclude our discussion with identification of some unresolved issues in pursuit of trust and reputation management. 相似文献
46.
SUMMARY A study is made of the effect of mesh distortion on the accuracy of transverse shear stresses and their first-order and second-order sensitivity coefficients in multilayered composite panels subjected to mechanical and thermal loads. The panels are discretized by using a two-field degenerate solid element, with the fundamental unknowns consisting of both displacement and strain components, and the displacement components having a linear variation throughout the thickness of the laminate. A two-step computational procedure is used for evaluating the transverse shear stresses. In the first step, the in-plane stresses in the different layers are calculated at the numerical quadrature points for each element. In the second step, the transverse shear stresses are evaluated by using piecewise integration, in the thickness direction, of the three-dimensional equilibrium equations. The same procedure is used for evaluating the sensitivity coefficients of transverse shear stresses. Numerical results are presented showing no noticeable degradation in the accuracy of the in-plane stresses and their sensitivity coefficients with mesh distortion. However, such degradation is observed for the transverse shear stresses and their sensitivity coefficients. The standard of comparison is taken to be the exact solution of the three-dimensional thermoelasticity equations of the panel. 相似文献
47.
Listeria monocytogenes strain Scott A in Tryptose Broth was treated with 100-300 ppm butylated hydroxyanisole (BHA), 300-700 ppm butylated hydroxytoluene (BHT) and 10-30 ppm tertiary butylhydroquinone (TBHQ). Resulting growth curves were fitted using the logistic model, and growth parameters [lag period (LP), generation time (GT), and maximum growth (MG)] were calculated. BHA and BHT inhibited Listeria monocytogenes by increasing LP and GT and decreasing MG. Extent of inhibition was concentration-dependent for cultures with BHA, but not with BHT. TBHQ at 10-30 ppm increased LP but did not affect other parameters. LP increased exponentially with increased BHA or TBHQ in Listeria culture. Concentrations of additive required to increase LP by one order of magnitude were 240 ppm for BHA and 26 ppm for TBHQ. 相似文献
48.
49.
NAEL N. ZAKI NEHAL S. AHMED AMAL M. NASSAR 《Petroleum Science and Technology》2013,31(9-10):1175-1193
ABSTRACT The efficiency of sodium lignin sulfonate (SLS) as an anionic surfactant derived from waste wood pulping industry in stabilizing an Egyptian heavy crude oil (Geisum)-in-water emulsions for pipeline transportation has been investigated. The stability and rheology of the emulsions stabilized by SLS or with a nonionic surfactant nonyl phenol diethylenetriamine formaldehyde ethoxylate (NDFE) individually or in a mixture have been studied. It has been found that the dynamic shear viscosity of the crude oil decreases substantially when it is emulsified with water in the form of an oil-in-water type of emulsion. The stability of the oil-in-water emulsion increases as the surfactant concentration increases. Potable water and saline water containing different molar concentrations of NaCI have been used to study the effect of aqueous phase salinity on the stability and viscosity of the emulsion. Surfactant dissolved in saline water has been utilized to find out the possibility of injecting the surfactant into a well bore to effect emulsification in the pump or tubing for enhancing the production of heavy crude oils as oil-in-water emulsion. The study revealed that, the viscosity of the emulsion containing potable water is always less than that containing saline water and the viscosity increases as the salt content increased. 相似文献
50.
AHMED M. SOLIMAN 《International Journal of Electronics》2013,100(4):461-464
A new structure for realizing an all-pass transfer function is given here. By adjusting one resistor the same configuration can realize a notch filter. Two special circuits using a minimum number of capacitors are derived from the general configuration, both are capable of realizing complex poles 相似文献