全文获取类型
收费全文 | 614篇 |
免费 | 42篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 6篇 |
综合类 | 9篇 |
化学工业 | 124篇 |
金属工艺 | 21篇 |
机械仪表 | 21篇 |
建筑科学 | 14篇 |
矿业工程 | 1篇 |
能源动力 | 38篇 |
轻工业 | 87篇 |
水利工程 | 6篇 |
石油天然气 | 5篇 |
无线电 | 80篇 |
一般工业技术 | 127篇 |
冶金工业 | 10篇 |
原子能技术 | 6篇 |
自动化技术 | 110篇 |
出版年
2024年 | 1篇 |
2023年 | 22篇 |
2022年 | 34篇 |
2021年 | 58篇 |
2020年 | 38篇 |
2019年 | 49篇 |
2018年 | 41篇 |
2017年 | 34篇 |
2016年 | 43篇 |
2015年 | 22篇 |
2014年 | 44篇 |
2013年 | 76篇 |
2012年 | 20篇 |
2011年 | 23篇 |
2010年 | 25篇 |
2009年 | 14篇 |
2008年 | 13篇 |
2007年 | 17篇 |
2006年 | 10篇 |
2005年 | 8篇 |
2004年 | 13篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1990年 | 1篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有665条查询结果,搜索用时 55 毫秒
61.
Jeff T. M. De Hosson Wouter A. Soer Andrew M. Minor Zhiwei Shan Eric A. Stach S. A. Syed Asif Oden L. Warren 《Journal of Materials Science》2006,41(23):7704-7719
As a tribute to the scientific work of Professor David Brandon, this paper delineates the possibilities of utilizing in situ transmission electron microscopy to unravel dislocation-grain boundary interactions. In particular, we have focused on the deformation characteristics of Al–Mg films. To this end, in situ nanoindentation experiments have been conducted in TEM on ultrafine-grained Al and Al–Mg films with varying Mg contents. The observed propagation of dislocations is markedly different between Al and Al–Mg films, i.e. the presence of solute Mg results in solute drag, evidenced by a jerky-type dislocation motion with a mean jump distance that compares well to earlier theoretical and experimental results. It is proposed that this solute drag accounts for the difference between the load-controlled indentation responses of Al and Al–Mg alloys. In contrast to Al–Mg alloys, several yield excursions are observed during initial indentation of pure Al, which are commonly attributed to the collective motion of dislocations nucleated under the indenter. Displacement-controlled indentation does not result in a qualitative difference between Al and Al–Mg, which can be explained by the specific feedback characteristics providing a more sensitive detection of plastic instabilities and allowing the natural process of load relaxation to occur. The in situ indentation measurements confirm grain boundary motion as an important deformation mechanism in ultrafine-grained Al when it is subjected to a highly inhomogeneous stress field as produced by a Berkovich indenter. It is found that solute Mg effectively pins high-angle grain boundaries during such deformation. The mobility of low-angle boundaries is not affected by the presence of Mg.Special title: Advanced Materials and Characterization: Proceedings of the Brandon Symposium; Guest Editors: Wayne D. Kaplan and Srinivasa Ranganathan 相似文献
62.
L. Gao X. Gao X. W. Hu Y. X. Jie H. Q. Liu M. Asif 《Journal of Infrared, Millimeter and Terahertz Waves》2004,25(6):891-895
In this paper the lasing modes and the propagation property of a CW DCN laser, which cavity is a 50 mm inner diameter with length of 3.4 m, were studied. The modes of 195 and 190 μm lines are well identified by the micrometer mount of the movable mirror in one end of the cavity. The beam profile is found to be qualitatively Gaussian in the far-field (Z > 4 m). 相似文献
63.
SHIRLENE M. ANTHONYSAMY NAZAMID BIN SAARI KHARIDAH MUHAMMAD FATIMAH ABU BAKAR RADZALI MUSE 《Journal of Food Biochemistry》2004,28(2):91-99
The effect of holding time, pH and temperature of sago pith slurry on its browning was evaluated. Holding time of sago pith slurry, which browning took place, proved to be an important factor in determining the amount of soluble phenolic compounds that were oxidized. This subsequently led to the development of color. The amount of (+)-catechin and (-)-epicatechin that was oxidized increased with pH particularly above pH 4.5. This resulted in simultaneous development of color in the sago pith slurry. The oxidation of phenolic compounds in acidic conditions was suggested to be caused by latent polyphenol oxidase (LPPO) as it is activated by acidic pH. The amount (+)-catechin and (-)-epicatechin oxidized also increased with increase in temperature particularly above 30C. 相似文献
64.
Riley William T.; Schumann Mary F.; Forman-Hoffman Valerie L.; Mihm Patricia; Applegate Bradford W.; Asif Ofer 《Canadian Metallurgical Quarterly》2007,38(1):44
Increased adoption of empirically supported treatments (ESTs) has been hindered in part by inadequate and inconvenient access to EST information and training. To improve diffusion of ESTs, the authors developed a Web application to provide practitioners with concise information by disorder on ESTs. The resulting site, therapyadvisor.com, was evaluated by 239 practicing psychologists to assess the usefulness of the site and explore possible interactions of EST attitudes on ratings of usefulness and impact. Two thirds of participants indicated using ESTs in practice, and limited time and resources were cited as primary barriers to EST adoption. The Web application was rated positively by most participants and was reported to increase awareness of and commitment to try ESTs among approximately 60% of participants. The results of this project support the feasibility of a Web application to increase diffusion and promote further adoption of ESTs. Technological and e-learning advances are promising directions for encouraging the adoption of ESTs specifically and evidence-based practice generally, particularly among busy practitioners who have inadequate time and resources for more traditional forms of dissemination and training. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
Muhammad Asif Zahoor Raja Siraj-ul-Islam Ahmad Raza Samar 《Neural computing & applications》2013,23(7-8):2199-2210
In this paper, a stochastic technique is developed to solve 2-dimensional Bratu equations using feed-forward artificial neural networks, optimized with genetic and interior-point algorithms. The 2-dimensional equations are first transformed into a 1-dimensional boundary value problem, and a mathematical model of the transformed equation is then formulated with neural networks using an unsupervised error. Network weights are optimized to minimize the error. Evolutionary computing based on genetic algorithms is used as a tool for global search, integrated with an interior-point method for rapid local convergence. The methodology is applied to solve three cases of boundary value problems for the Bratu equations. The accuracy, convergence and effectiveness of the scheme is validated for a large number of simulations. Comparison of results is made with the exact solution derived using MATHEMATICA, and is found to be in good agreement. 相似文献
66.
Sajjad Muhammad Asif Sana Ullah Guan Linlin Jiao Yangjing Jiang Yuhan Zhang Linlin Wen Jia Zhang Shuyu Lin Yuting Zhang Shuangshuang Ding Zhiwei Ren Yang Zhou Xiaowei Hu Wanbiao Liu Zhu 《Journal of Inorganic and Organometallic Polymers and Materials》2021,31(11):4440-4441
Journal of Inorganic and Organometallic Polymers and Materials - The original version of this article unfortunately contained mistakes. In line 9 of the abstract, 5% should read as 2%. The... 相似文献
67.
The dynamics of a gas‐solid fluidized bed containing Geldart Group D particles mixed with a small proportion of Geldart Group B particles are investigated using pressure fluctuations data. Time series analysis, using a variety of nonlinear dynamics tools, shows that the slugging present with Group D particles can be suppressed by the addition of a small proportion of Group B particles. The power spectra and the auto‐correlation function are used for a preliminary evaluation of dominant slug frequencies. It is shown that the bed fluidized with the mixture of Group D and B particles behaves in a less periodic manner and is dominated by more random bubble motion. On the other hand, the correlation integral is used to analyze the chaotic behaviour of the flow, through evaluation of the fractal structure of the reconstructed attractors. It is shown that the bed fluidized with Group D particles is characterized by a combination of steady slug motion and irregular particles motion. The behaviour of the fluidized bed of Group D/B particles mixture is characterized by a single correlation dimension for a wide range of fluidization velocities. 相似文献
68.
Rai Muhammad Sarfraz Mahmood Ahmad Asif Mahmood Hira Ijaz 《Polymer-Plastics Technology and Engineering》2018,57(12):1175-1187
Current research work was conducted for enhancing solubility of rosuvastatin calcium. A highly stable, biocompatible, and nontoxic β-cyclodextrin-g-poly(methacrylic acid) graft polymeric network was developed. Formulations proved entrapment efficacy (%) in between 82.30?±?0.25 and 89.00?±?0.25 and gel fraction between 90.34?±?1.012 and 95.25?±?1.331. Formulation HM2 had shown optimum swelling and drug release, i.e., 85.74% at pH 6.8. The best-fit model was first-order kinetics with anomalous diffusion as release mechanism. Likewise, solubility enhancement, i.e., 9.59-folds was determined at pH 6.8. It was concluded that hydrogel microparticles are the promising tools for improving solubility and bioavailability of hydrophobic drugs. 相似文献
69.
Farhan Saeed Saleem Anwar Muhammad Shafiq Irfan Asif Ali Qaiser Yasir Qayyum Gill 《应用聚合物科学杂志》2018,135(38)
Thermoplastic vulcanizates (TPVs) of polypropylene random copolymer (PPRC) with ethylene–propylene diene monomer rubber (EPDM) were prepared through in situ and ex situ compatibilization techniques. Silanized silica as nanofiller was incorporated in the ex situ compatibilized TPVs. Mechanical properties were measured for different formulated TPVs with increasing loading of EPDM from 10 to 30 phr. A comparative data is generated to discuss the effect of two compatibilization techniques and addition of silica filler in the TPVs. The degradation studies were also carried out to check the stability of the blends under harsh ultraviolet environment. The in situ compatibilized TPVs provided better overall mechanical properties. Moreover, it is worth mentioning that the properties of ex situ compatiblized TPVs were enhanced by incorporation of silanized silica filler. Silanized silica filler helped in reducing the die swell significantly. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46726. 相似文献
70.
Irfana Kolangare Moideen Arun Mohan Isloor Asif Ali Qaiser Ahmed Fauzi Ismail Mohd Sohaimi Abdullah 《Korean Journal of Chemical Engineering》2018,35(6):1281-1289
This work deals with a simple and eco-friendly approach for the development of ultrafiltration membranes for the separation of environmentally hazardous substances from the water source. Polysulfone and sulfonated polyphenylsulfone blend ultrafiltration membranes were fabricated by the non-solvent induced phase inversion technique. Prepared membranes were characterized for their morphology, hydrophilicity, porosity, filtration and antifouling properties. The blend membranes with 15 wt% of sPPSU demonstrated the best performance with water flux of 190.33 Lm?2h?1 and flux recovery ratio of 86.56%. The effect of aq. glycine betaine (GB) coagulation bath on the membrane property and performance was studied and compared with commonly used additives such as NaCl and NMP. The GB in coagulation bath exhibited better flux and performance with protein rejection of 66.3%, 74.0% and 91.2% for trypsin, pepsin, and bovine serum albumin, respectively, and heavy metal rejection of 75.2% and 87.6% for polymer enhanced ultrafiltration of Cd2+ and Pb2+ ions, respectively. 相似文献