全文获取类型
收费全文 | 1087篇 |
免费 | 83篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 15篇 |
综合类 | 3篇 |
化学工业 | 274篇 |
金属工艺 | 30篇 |
机械仪表 | 37篇 |
建筑科学 | 43篇 |
矿业工程 | 1篇 |
能源动力 | 54篇 |
轻工业 | 95篇 |
水利工程 | 23篇 |
石油天然气 | 5篇 |
无线电 | 109篇 |
一般工业技术 | 235篇 |
冶金工业 | 57篇 |
原子能技术 | 42篇 |
自动化技术 | 160篇 |
出版年
2024年 | 4篇 |
2023年 | 14篇 |
2022年 | 52篇 |
2021年 | 82篇 |
2020年 | 65篇 |
2019年 | 70篇 |
2018年 | 66篇 |
2017年 | 70篇 |
2016年 | 94篇 |
2015年 | 36篇 |
2014年 | 59篇 |
2013年 | 81篇 |
2012年 | 71篇 |
2011年 | 86篇 |
2010年 | 58篇 |
2009年 | 39篇 |
2008年 | 43篇 |
2007年 | 26篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 17篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有1183条查询结果,搜索用时 15 毫秒
101.
I Mahmood 《Canadian Metallurgical Quarterly》1998,63(26):2365-2371
The objective of this study is to predict pharmacokinetic parameters (clearance, volume of distribution at steady state, and elimination half-life) in humans from animal data for drugs which are renally secreted in humans. Pharmacokinetic parameters of ten drugs were scaled-up from animal data obtained from the literature. Using simple allometry (pharmacokinetic parameter of interest vs body weight), total, renal and nonrenal clearances, volume of distribution and half-life were predicted in humans. The predicted parameters were compared with the observed parameters. The results of the study indicated that it is likely that the predicted total and renal clearances from animal data will be underestimated in humans for renally secreted drugs. The prediction of renal clearance was improved by normalizing the renal clearance by a 'correction factor' for animals who exhibited renal secretion. The predicted volume and half-life were comparable with the observed values in man. Overall, the results of this study indicate that caution should be employed in interpreting the total and renal clearance of renally secreted drugs predicted by the allometric approach. 相似文献
102.
Mahmood Thobani Levente L. Diosady 《Journal of the American Oil Chemists' Society》1997,74(3):207-214
The equilibrium relationships in the extraction process that was developed in our research laboratory for the treatment of
canola were studied. In the process, hexane is used as well as CH3OH that contains 5% (vol/vol) H2O and 0.08% (w/w) NaOH to simultaneously produce improved meal and high-quality oil. Equilibrium data for canola oil in the
hexane-CH3OH/H2o/NaOH, meal-hexane, and meal-CH3OH/H2O/NaOH-hexane systems are reported. A high partition coefficient for oil between hexane and the polar phase provided a large
driving force for mass transfer. The presence of the CH3OH phase improved oil extraction, probably by rupturing the cell structure. The process proved to be a somewhat less desirable
replacement for CH3OH/H2O/NH3 extraction and recovered 93.5% of the oil and 91.8% of the protein in the seed, while with CH3OH/H2O/NH3, the oil and protein recoveries were 96.8 and 94.0%, respectively. The NaOH treatment removed only 50.2% of the glucosinolates,
and some of the oil was hydrolyzed by the NaOH, making the process less effective, despite its simplicity. 相似文献
103.
Zhongrui Li Enkeleda Dervishi Yang Xu Viney Saini Meena Mahmood Olumide Dereck Oshin Alexandru R. Biris Alexandru S. Biris 《Catalysis Letters》2009,131(3-4):356-363
A comparison of different catalyst systems (Fe–Mo, Co–Mo or Ni–Mo nanoparticles supported on calcium carbonate) has been performed in order to optimize the carbon nanotube (CNT) growth. The influences of the reaction temperature, metal loading and carbon source on the synthesis of CNTs were investigated. Dense CNT networks have been synthesized by thermal chemical vapor deposition (CVD) of acetylene at 720 °C using the Co–Mo/CaCO3 catalyst. The dependence of the CNT growth on the most important parameters was discussed exemplarily on the Co catalyst system. Based on the experimental observations, a phenomenological growth model for CVD synthesis of CNTs was proposed. The synergy effect of Mo and active metals was also discussed. 相似文献
104.
105.
Simultaneous measurements of thermal conductivity and thermal diffusivity of composite red-sand bricks, glycerine and mercury have been made at room temperature by the recently developed transient plane source (TPS) technique. This paper describes, in brief, the theory and the experimental conditions for the simultaneous measurements of thermal conductivity and thermal diffusivity of insulators, fluids and metals. The source of heat is a hot disc made out of bifilar spirals. The disc also serves as a sensor of temperature increase in the sample. The measured values of the thermal conductivity and thermal diffusivity of these samples are in agreement with the values reported earlier using other methods. The advantage of the TPS technique is the simplicity of the equipment, simultaneous information on thermal conductivity and thermal diffusivity, and also the applicability of the technique to insulators, fluids and metals. 相似文献
106.
Theoretically the computer can offer the architect significant help during the preliminary design stages. To take full benefit of its capabilities it is necessary to use the computer for the design process itself. To this end, a program has been written that concentrates on ease of use so that the machine does not impede the creative process. The program works through the manipulation of design elements such as spaces and windows, not graphical ones. The result is a tool which offers improved efficiency, but is very different from current methods that use paper in preliminary design. 相似文献
107.
Leonard Forbes René Brown Mahmood Sheikholeslam Wayne Current 《Solid-state electronics》1979,22(4):391-397
C.T. Sah has published a review article demonstrating the application of high-frequency small signal capacitance and current transients of a space charge layer. Application of such transients is a powerful technique in characterizing deep level imperfection center concentrations, energy levels, thermal and optical emission rates and thermal capture cross sections. The MOSFET device structure is particularly convenient for low temperature measurements of shallow levels where deionization occurs and the substrate becomes highly resistive, seriously limiting capacitance transient techniques. Examples are given by results on indium-doped silicon, such as employed in extrinsic IR detectors. The emission time constant of holes from the neutral indium center has been found to depend on the indium doping. Measurements on lightly doped samples yield a value for the emission rate, , of 6.0 msec at 77°K and a thermal activation energy of 0.15 eV. Measurements on heavily doped samples yield values of of 20 μsec at 77°K and an activation energy of 0.117 eV. These results are consistent with the Poole-Frenkel effect describing field enhanced thermal emission of holes from the indium center. Measurements of the hole capture coefficient at 77°K yield values for cp of 3.7 × 10?7 cm3/sec. These measurements have been made on heavily doped samples. The capture coefficient measured is the zero field or quasi-equilibrium value. The temperature dependence of the hole capture coefficient has been found to be T?4. Small transients in the thermal emission rate measurements have been observed. These transients have thermal activation energies of around 0.08 eV and are associated with the 0.11 eV level as reported by Hughes Research Labs after accounting for barrier lowering by the Poole-Frenkel effect. 相似文献
108.
109.
D.E. Brown M.N. Mahmood A.K. Turner S.M. Hall P.O. Fogarty 《International Journal of Hydrogen Energy》1982,7(5):405-410
An electrocatalyst for hydrogen evolving cathodes has been developed for use in alkaline media. The materials employed in manufacturing the coating are relatively cheap transition metals. The results of a variety of performance tests are reported. The electrodes exhibit a low overvoltage for hydrogen evolution (70–90 mV at 70°C and 1A cm?2 in 5 N KOH), stability to abuse (e.g. current interruption or reversal) and a long cathode life under operating conditions. 相似文献
110.
Stanton de Riel Imrana Mahmood Francisco Alvarez Shashank Mahashabde Sharad Govil 《Drug development and industrial pharmacy》1993,19(6):643-652
An assay of water in adhesive monolithic transdermal drug dosage forms ('patches'), using lamination to Tyvek, and gaseous extraction in an evaporator oven into a Karl Fischer titrator, is described. The method is simple, linear, accurate, specific and more sensitive than alternatives. 相似文献