全文获取类型
收费全文 | 9367篇 |
免费 | 834篇 |
国内免费 | 89篇 |
专业分类
电工技术 | 180篇 |
综合类 | 41篇 |
化学工业 | 2615篇 |
金属工艺 | 213篇 |
机械仪表 | 394篇 |
建筑科学 | 354篇 |
矿业工程 | 20篇 |
能源动力 | 615篇 |
轻工业 | 910篇 |
水利工程 | 190篇 |
石油天然气 | 140篇 |
武器工业 | 5篇 |
无线电 | 976篇 |
一般工业技术 | 1613篇 |
冶金工业 | 210篇 |
原子能技术 | 67篇 |
自动化技术 | 1747篇 |
出版年
2024年 | 40篇 |
2023年 | 191篇 |
2022年 | 346篇 |
2021年 | 611篇 |
2020年 | 550篇 |
2019年 | 680篇 |
2018年 | 775篇 |
2017年 | 732篇 |
2016年 | 723篇 |
2015年 | 429篇 |
2014年 | 711篇 |
2013年 | 1037篇 |
2012年 | 651篇 |
2011年 | 731篇 |
2010年 | 471篇 |
2009年 | 404篇 |
2008年 | 244篇 |
2007年 | 181篇 |
2006年 | 148篇 |
2005年 | 101篇 |
2004年 | 101篇 |
2003年 | 58篇 |
2002年 | 57篇 |
2001年 | 28篇 |
2000年 | 23篇 |
1999年 | 25篇 |
1998年 | 22篇 |
1997年 | 18篇 |
1996年 | 23篇 |
1995年 | 19篇 |
1994年 | 10篇 |
1993年 | 15篇 |
1992年 | 10篇 |
1991年 | 17篇 |
1990年 | 16篇 |
1989年 | 12篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 14篇 |
1983年 | 12篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1973年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Mohammad Asif 《Powder Technology》2004,145(2):113-122
Contrary to the widely held notion that the total bed height of a binary solid fluidized bed will be the sum of heights of the two individual mono-component beds fluidized at the same velocity, significant negative deviations have been observed in our experimental investigation. The negative deviations, signifying a contraction of the total volume of the binary solid fluidized bed, could sometimes be as high as 25% of the actual volume. The volume contraction has been found to depend mainly upon the degree of solids mixing prevailing in the bed irrespective of whether it is fully fluidized or not. The composition of the binary solid fluidized was another important factor that influenced the contraction behaviour of the bed besides the size ratio of the two constituent solid species of the binary present in the bed. 相似文献
942.
Michael Wootton Mohammad Shams-Ud-Din 《Journal of the science of food and agriculture》1986,37(4):387-390
Wheat bran was sieved into coarse, medium and fine fractions prior to extraction with tap water. Bran, bran extract and bran residue were analysed for moisture, protein, fat, ash, pentosan and phytic acid. Farinograph measurements and baking tests showed maximum dough resistance and loaf volume of a white flour were both increased by the addition of the residue. Both these parameters were substantially decreased by bran extract and, to a lesser degree, by the bran itself. These findings were common amongst the size fractions although the residue from the coarse bran had the greatest effect on loaf volume and dough properties. 相似文献
943.
Mohammad I. El-Khaiary 《化学工程与技术》1997,20(5):338-341
A study was conducted on the stoichiometry of the reaction that takes place on the extraction of ferric ions by didodecyl naphthalene sulphonic acid (HDDNSA) from phosphoric acid solutions. The experimental results were numerically analyzed by nonlinear regression. It was found that ferric forms two compounds with HDDNSA, namely Fe(DDNSA)3, and FeHPO4-DDNSA. The values of the equilibrium constants of the reactions involved were also calculated. 相似文献
944.
Widespread use of non-volatile memories, especially flash memories, in diverse applications such as in mobile computing and system-on-chip is becoming a common place. As a result, testing them for faults and reliability is drawing considerable interest of designers and researchers. One of the most predominant failure modes for which these memories must be tested is called disturb faults. In this paper, we first analyze different defects that are responsible for disturb faults using a 2-dimension device simulator. We determine the impact of various defects on cell performance and develop a methodology based on channel erase technique to detect these defects. Our tests are efficient and can be converted to march tests prevalently used to test memories. We also propose a very low cost design-for-testability approach that can be used to apply the test technique developed in this paper. 相似文献
945.
Seyed Mohamad Mahdi DoustMohamadi Morteza Vahedpour Mohammad Hossein Rasoulifard Azam Heidari 《Water and Environment Journal》2023,37(1):154-165
In the present study, the photooxidative degradation of Acid Red 14 (AR 14) was investigated in the UV/persulfate process, and the results of the degradation rate of AR 14 were parametrically represented by ordinary differential equations to find mathematical model for the degradation rate of AR 14 in this process. Our experimental observations led to a model for AR 14 degradation in the UV/persulfate system that could be used to predict removal efficiency by changes of S2O82− (X1) and dye concentration (X2), pH (X3), temperature (X4) and also distance of UV lamp from solution (X5). It was found that persulfate and dye concentrations were the most important parameters for AR 14 degradation rate. Moreover, the results showed that the degradation rate was in good agreement with the first-order kinetics for all the parameter values studied. Moreover, the results of the mathematical model agree well with the experimental values (R2 = 0.96). Our findings in this study showed that degradation efficiency of UV/S2O82− process for AR 14 was obtained as 98%. Therefore, this model could be applicable before scaling up the AR 14 degradation using UV/persulfate process. 相似文献
946.
Mohammad Ali Takassi Ghasem Zargar Mohammad Madani Amin Zadehnazari 《Petroleum Science and Technology》2017,35(4):385-391
Most of the synthetic surfactants investigated with the aim of enhanced chemically oil recovery in the literature have environmental drawbacks. In this work, application of an environmentally-friendly synthetic surfactant as an enhanced oil recovery agent is introduced by measuring interfacial tension of water–kerosene systems and wettability alteration of carbonate pellets. For this purpose, an amino acid-based surfactant was initially synthesized using a new synthetic approach which was subsequently confirmed by spectra of Fourier transform infrared and Proton nuclear magnetic resonance. Results showed a value of critical micelle concentration in the range of 9000–9100 ppm for this surfactant. Results also demonstrated a decrease of 38.53% in water–kerosene system interfacial tension and a 17.76% reduction in oil-wetness of the carbonate pellets. 相似文献
947.
Wei Gao Mohammad Reza Farahani Muhammad K. Jamil Muhammad K. Siddiqui Hafiz Muhammad Afzal Siddiqui Muhammad Imran 《Petroleum Science and Technology》2017,35(2):183-189
Different approaches have been used to convert the waste materials into a clean syngas or other chemicals such as methanol. Among them, pyrolysis is a good candidate to produce the synthesis gas and volatile matters for industrial and refinery applications. In this work, we studied the kinetic and chemical behavior of three Iranian waste oils through a kinetic model and an experimental study. The experiments carried out in a micro-FB reactor, which is a good option for low emissions. Results showed that the reaction temperature and reaction rate are two of the most important factors for maximum conversion level of fuel. Results also showed an optimum value for reaction rate. The modeling results validated against the experimental measurements and found to be in good agreements. 相似文献
948.
Alireza Afsharpour Atefeh Afsharpour Mohammad Mohammadi-Khanaposhtani 《Petroleum Science and Technology》2017,35(3):299-305
In this survey, we use the emPR-CPA equation of state to model a ternary system of H2S solubility in MDEA aqueous solution at different solution compositions, temperatures, pressures, and acid gas loadings. For electrolyte part of the model, MSA theory and the Born term were used. There were 302 experimental data used in this work. To model a ternary system, at first pure components, then binary subsystems, and finally ternary system were modeled using a reactive bubble point pressure calculation method. An overall absolute average deviation percentage equal to 20.85 was achieved so that show the model efficiency for correlation of such systems. 相似文献
949.
Mohammad Madani Peyman Abbasi Ghasem Zargar Pezhman Abbasi 《Petroleum Science and Technology》2017,35(23):2179-2186
Development of reliable and accurate models to estimate carbon dioxide–brine interfacial tension (IFT) is necessary, since its experimental measurement is time-consuming and requires expensive experimental apparatus as well as complicated interpretation procedure. In the current study, feed forward artificial neural network is used for estimation of CO2–brine IFT based on data from published literature which consists of a number of carbon dioxide–brine interfacial tension data covering broad ranges of temperature, total salinity, mole fractions of impure components and pressure. Trial-and-error method is utilized to optimize the artificial neural network topology in order to enhance its capability of generalization. The results showed that there is good agreement between experimental values and modeling results. Comparison of the empirical correlations with the proposed model suggests that the current model can predict the CO2–brine IFT more accurately and robustly. 相似文献
950.
Mohammad Karim Dehghan Manshadi Danial Khojasteh Mehdi Mohammadi Reza Kamali 《International Journal of Numerical Modelling》2016,29(5):845-858
Lab‐on‐a‐chip (LOC) integrated microfluidics has been a powerful tool for new developments in analytical chemistry. These microfluidic systems enable the miniaturization, integration and automation of complex biochemical assays through the reduction of reagent use and enabling portability. Electroosmotic micropumps could be employed as powerful tools to generate required flow in point of care (POC) devices. In the present study, parallel electroosmotic micropumps are investigated to improve the efficiency of simple micropumps. According to the results, parallel micropumps generate higher flow rate in comparison with conventional electroosmotic pump. In the last decade, a large variety of non‐Newtonian fluids have been utilized in biomedical application but requirements for a POC device such as high efficient driving flow, miniaturization and simple handling of POC devices remain unmet. As a consequence, in this study, power law model as non‐Newtonian fluids that flow through the parallel micropumps are investigated in order to enhance fluid pumping and decreasing voltage requirement.. It is found that as the power law index increases the mass flow rate decreases. Also, the flow rate is almost constant for the higher power law index. Obtained results, demonstrated that parallel micropump could enhance pumping of non‐Newtonian fluid (blood) up to 30%. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献