全文获取类型
收费全文 | 2978篇 |
免费 | 158篇 |
国内免费 | 24篇 |
专业分类
电工技术 | 45篇 |
综合类 | 5篇 |
化学工业 | 685篇 |
金属工艺 | 89篇 |
机械仪表 | 96篇 |
建筑科学 | 98篇 |
矿业工程 | 6篇 |
能源动力 | 398篇 |
轻工业 | 268篇 |
水利工程 | 15篇 |
石油天然气 | 60篇 |
无线电 | 256篇 |
一般工业技术 | 566篇 |
冶金工业 | 147篇 |
原子能技术 | 14篇 |
自动化技术 | 412篇 |
出版年
2023年 | 60篇 |
2022年 | 121篇 |
2021年 | 182篇 |
2020年 | 125篇 |
2019年 | 106篇 |
2018年 | 187篇 |
2017年 | 134篇 |
2016年 | 151篇 |
2015年 | 89篇 |
2014年 | 138篇 |
2013年 | 250篇 |
2012年 | 155篇 |
2011年 | 191篇 |
2010年 | 119篇 |
2009年 | 135篇 |
2008年 | 99篇 |
2007年 | 94篇 |
2006年 | 83篇 |
2005年 | 44篇 |
2004年 | 56篇 |
2003年 | 61篇 |
2002年 | 41篇 |
2001年 | 30篇 |
2000年 | 29篇 |
1999年 | 30篇 |
1998年 | 50篇 |
1997年 | 33篇 |
1996年 | 29篇 |
1995年 | 39篇 |
1994年 | 18篇 |
1993年 | 25篇 |
1992年 | 19篇 |
1991年 | 18篇 |
1990年 | 13篇 |
1989年 | 19篇 |
1988年 | 12篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 21篇 |
1984年 | 16篇 |
1983年 | 8篇 |
1982年 | 15篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 11篇 |
排序方式: 共有3160条查询结果,搜索用时 31 毫秒
991.
Shafa’atu Giwa Ibrahim Wan Zunairah Wan Ibadullah Nazamid Saari Roselina Karim 《International Journal of Food Science & Technology》2022,57(7):4096-4106
Tofu was made by substituting kenaf seed (K) with soybean (S) at 100 (positive control), 50%, 40%, 30%, 20%, 10% and 0% (negative control). The results indicated that kenaf seed substitution at all ratios significantly increased the soluble solids and protein content of the milky extracts. The yield, moisture and protein content of the tofu were significantly increased with the increase in kenaf seed substitution, while the lipid content was significantly decreased. The tofu made with kenaf seed substitution of 50%, 40% and 30% had the same protein content (43.76–45.36 g/100 g) with the positive control (45.36 g/100 g), but a significantly higher lipid content (32.00–35.75 g/100 g) than that of the positive control (27.50 g/100 g). The microstructure of the tofu revealed that only the positive control had a honey-comb structure, whilst the tofu made from kenaf seed-soybean blends had a pseudo-honey like structure. Up to 30% of soybean can be added into the kenaf-based tofu, without any negative effect on the textural and colour properties and, protein content, but significantly improved the essential amino acids content of the kenaf-based tofu. Therefore, the blend of 70K:30S ratio using 0.5 g% glucono delta-lactone as a coagulant is recommended to produce kenaf seed-soybean tofu. 相似文献
992.
Hamdy Mohamed S. Alhanash Abdullah M. Eissa Murad Ibrahim Fatma A. Abboud Mohamed 《Journal of Porous Materials》2022,29(4):1287-1298
Journal of Porous Materials - The selective oxidation of cyclohexane was catalyzed by applying a new series of catalytic materials. The new catalytic series consists of two different active sites... 相似文献
993.
Four soda lime silicate glass samples of composition (70 % SiO2+ 20 % Na2O+ 10 % CaO mol %) were prepared after adding 5 wt% cement dust to each sample mixture besides 0.1 wt% of one transition metal (TM) oxide of Fe, Co or Cu. The four samples were melted by a conventional melt-annealing technique at 1400 °C for 2.5 h. Density, UV/VIS, FTIR and DC conductivity measurements were performed for each glass. Experimental results indicate that there are only slight differences in the density values. The optical spectra reveal that the TM free sample and the sample containing iron ions have the same spectral features while the samples containing copper or cobalt exhibit distinct characteristic absorption bands due to each TM ion. FTIR spectra reveal characteristic vibrational bands due to stretching and bending modes of the silicate network. DC conductivity data show variations in the values of the studied samples according to the type of TM ions added. All the experimental results were correlated with each other in accordance with the current views on the constitution of the studied glasses. 相似文献
994.
Cassio Barbosa Ibrahim de Cerqueira Abud Tatiana Silva Barros Sheyla Santana de Carvalho 《Journal of Failure Analysis and Prevention》2016,16(1):104-108
Powder metallurgy operations comprise the use of compaction dies and punches for transforming a mass of metallic powders into a porous block of aggregated particles with limited “green” strength. In this kind of application, dies and punches manufactured with tool steel are subjected to heavy loads to compress the metallic powders and form the block, which will be subjected to further consolidation operations such as sintering and/or some mechanical forming operation, such as forging or rolling. In general tool steels are high carbon and high alloyed steels designed for reaching high levels of mechanical strength, sufficient for his type of loading. However, defects on the surface of this material can lead to stress concentration, thus decreasing its fracture strength and eventually leading to failure. In this study, techniques such as optical and scanning electron microscopy are used to evaluate the possible causes of the failure of a compaction punch. The results indicated that machining grooves acted as stress concentrations which led to the premature fracture of the punch. 相似文献
995.
Ahmed Mabrouk Norhidayah Hassim Ibrahim Elshafiey 《Journal of Real-Time Image Processing》2016,11(3):611-623
Identification of oblique lines of a particular slope is needed for various applications such as motion tracking for smart cameras. Wavelets and gradient-based techniques, such as Sobel and Canny, do not classify edges based on their slopes. The Hough transform (HT) does classify edges based on their slopes but with high computational complexity, even using its most improved versions. This paper presents a computationally efficient technique for detecting edges of a particular slope. The angle of the required edges is converted into pixel increments over rows and columns. Using these two simple parameters, parallel, oblique lines of a particular slope are formed. A first-order, orthonormal Haar low-pass filter (LPF) is used over the formed lines to filter out undesired edges. The hardware architecture of the proposed technique is fully described, including processing time, based on the number of clock cycles, and fixed-point implementation. A line-based memory mechanism was used to minimize the memory requirements to two simple registers. To demonstrate the computational advantage of the proposed technique, it is compared to the Sobel, Canny and HT detectors. 相似文献
996.
Ibrahim Onifade Romain Balieu Bjorn Birgisson 《Mechanics of Time-Dependent Materials》2016,20(3):421-439
This paper presents a new interpretation for the Superpave IDT strength test based on a viscoelastic-damage framework. The framework is based on continuum damage mechanics and the thermodynamics of irreversible processes with an anisotropic damage representation. The new approach introduces considerations for the viscoelastic effects and the damage accumulation that accompanies the fracture process in the interpretation of the Superpave IDT strength test for the identification of the Dissipated Creep Strain Energy (DCSE) limit from the test result. The viscoelastic model is implemented in a Finite Element Method (FEM) program for the simulation of the Superpave IDT strength test. The DCSE values obtained using the new approach is compared with the values obtained using the conventional approach to evaluate the validity of the assumptions made in the conventional interpretation of the test results. The result shows that the conventional approach over-estimates the DCSE value with increasing estimation error at higher deformation rates. 相似文献
997.
This study presents energy and exergy analyses and sustainability assessment of one novel and three conventional types of air cooling systems for building applications. First, effectivenesses of the systems are determined using energy analysis method. Second, exergy aspects of the systems are investigated for twelve different dead state temperatures varying from −5 °C to 50 °C with a temperature interval of 5 °C. The specific exergy flows of humid air, dry air and water, exergy efficiency, and specific exergy destruction are then calculated. Sustainability index is also used to define and discuss the systems’ sustainability aspects. Finally, the results obtained here show that at the dead state temperatures of higher than 23 °C (comfort temperature), exergy efficiency and sustainability of the novel system, which is based on the novel Maisotsenko cycle (M-Cycle), is higher than those of the conventional systems. At a dead state temperature of 50 °C, novel cooling system's exergy efficiency can reach 60.329% as the maximum, while the minimum exergy efficiency of other conventional cooling systems becomes as low as 35.866%, respectively. 相似文献
998.
Adrian Cheng Yong Choo Paridah Md. Tahir Alinaghi Karimi Edi Suhaimi Bakar Khalina Abdan Azmi Ibrahim Loh Yueh Feng 《Holz als Roh- und Werkstoff》2011,69(3):501-503
Large variations in the stem of oil palm in terms of moisture content and density hinder its full utilization in the plywood industry. In this study, the density and moisture content (MC) pattern throughout the trunk of the oil palm tree were measured and established. The veneer samples were taken from various sections i.e., top, bottom, outer and inner parts of the trunk and the density and moisture content of each veneer were then measured. The results showed that there was a decrease of density and an increase of moisture content in the veneers as they were peeled progressively towards the inner portion of the trunk. It was also discovered that veneers taken from the top part of the stem had higher density but did not have a significant difference in MC compared to veneers taken from the bottom part of the stem. 相似文献
999.
Ibrahim A. Abbas 《International Journal of Thermophysics》2012,33(3):567-579
In this article, an estimation is made to investigate the transient phenomena in the magneto-thermoelastic model in the context
of the Lord and Shulman theory in a perfectly conducting medium. A finite element method is proposed to analyze the problem
and obtain numerical solutions for the displacement, temperature, and radial and hoop stresses. The boundary conditions for
the mechanical and Maxwell’s stresses at the internal and outer surfaces are considered. An application of a hollow cylinder
is investigated where the inner surface is traction free and subjected to thermal shock, while the outer surface is traction
free and thermally isolated. The displacement, incremental temperature, and the stress components are obtained and then presented
graphically. Finally, the effects of the presence and absence of reinforcement on the temperature, stress, and displacement
are studied. 相似文献
1000.