全文获取类型
收费全文 | 1322篇 |
免费 | 27篇 |
专业分类
电工技术 | 114篇 |
化学工业 | 259篇 |
金属工艺 | 64篇 |
机械仪表 | 25篇 |
建筑科学 | 18篇 |
矿业工程 | 2篇 |
能源动力 | 35篇 |
轻工业 | 125篇 |
水利工程 | 6篇 |
石油天然气 | 3篇 |
无线电 | 139篇 |
一般工业技术 | 232篇 |
冶金工业 | 244篇 |
原子能技术 | 25篇 |
自动化技术 | 58篇 |
出版年
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 28篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 8篇 |
2016年 | 20篇 |
2015年 | 25篇 |
2014年 | 24篇 |
2013年 | 71篇 |
2012年 | 45篇 |
2011年 | 65篇 |
2010年 | 54篇 |
2009年 | 55篇 |
2008年 | 69篇 |
2007年 | 64篇 |
2006年 | 51篇 |
2005年 | 52篇 |
2004年 | 39篇 |
2003年 | 50篇 |
2002年 | 33篇 |
2001年 | 34篇 |
2000年 | 28篇 |
1999年 | 34篇 |
1998年 | 103篇 |
1997年 | 67篇 |
1996年 | 43篇 |
1995年 | 26篇 |
1994年 | 29篇 |
1993年 | 28篇 |
1992年 | 11篇 |
1991年 | 12篇 |
1990年 | 11篇 |
1989年 | 14篇 |
1988年 | 14篇 |
1987年 | 13篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 9篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 3篇 |
1972年 | 2篇 |
排序方式: 共有1349条查询结果,搜索用时 515 毫秒
121.
C Ogino Y Negi T Matsumiya K Nakaoka A Kondo S Kuroda S Tokuyama U Kikkawa T Yamane H Fukuda 《Canadian Metallurgical Quarterly》1999,125(2):263-269
Phospholipase D (PLD), secreted into the culture medium of an actinomycete, Streptoverticillium cinnamoneum, has been purified to homogeneity and characterized. The Stv. cinnamoneum PLD efficiently catalyzes both the hydrolysis and transphosphatidylation of various phospholipids, including phosphatidylethanolamine (PE), phosphatidylcholine (PC), and phosphatidylserine (PS). However, the substrate specificity differs between the two reactions; PE serves as the most preferred substrate for the hydrolysis, but PC and PS are better substrates than PE for the transphosphatidylation. In addition, the transphosphatidylation but not the hydrolysis of PE and PC is markedly activated on the addition of metal ions, especially Al3+. Nucleotide and amino acid sequence determination of the Stv. cinnamoneum PLD revealed the presence of common structural motifs identified in all PLD sequences from various species. 相似文献
122.
Norihito Mayama Hiroyuki Yoshida Tatsuo Iwata Kaoru Sasakawa Atsushi Suzuki Yuya Hanaoka Yoshihiro Morita Akito Kuroda Masanori Owari 《Diamond and Related Materials》2010,19(7-9):946-949
In this study, we report the characterization of carbonaceous films deposited on metal substrates by liquid-phase electrodeposition in methanol. The characterization of carbonaceous films by electrodeposition was examined by means of Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS), secondary ion mass spectrometry (SIMS), atom probe (AP) and high resolution-elastic recoil detection analysis (HR-ERDA). From these results, it was found that the films deposited on the metal substrates were composed of the sp2 and sp3 carbon contents, of which the ratio was about 7:3. Furthermore, the films by electrodeposition contained much hydrogen. The hydrogen contents in the surface were about 60 at.% and those in the subsurface were a few 10 at.%. 相似文献
123.
124.
Engineers have long believed a direct-fired heater (DFH) for deodorization is always in danger of over-heating. Commercial
tests done in recent years have proved this danger can be avoided by proper furnace design. At least ten commercial deodorizers
with this system are now used in Asia. A new deodorizer with a DFH was designed and built in 1986 in Taiwan. It features a
single-shell design and steam-stripping of deep oil layers. It has been operated successfully for several years. The deodorized
oil was compared with oil produced by conventional deodorizers. The new deodorizer with a DFH revealed several advantages. 相似文献
125.
High-speed n-InAlAs/InGaAs HEMT large-scale integrated circuits must have uniform device parameters. A selectively dry-etched n+ -GaAs/N-InAlAs/InGaAs HEMT which has a very uniform threshold voltage is discussed. Despite the high dislocation density at the n+-GaAs layer, its performance is excellent. For a gate length of 0.92 μm, the maximum transconductance of the HEMT is 390 mS/mm. The measured current-gain cutoff frequency is 23.7 GHz, and the maximum frequency of oscillation is 75.0 GHz. The standard deviation of the threshold voltage across a 2-in wafer is as low as 13 mV 相似文献
126.
Kyoo-Seung Han Seung-Wan Song Hirofumi Fujita Masahiro Yoshimura Elton J. Cairns Soon-Ho Chang 《Journal of the American Ceramic Society》2002,85(10):2444-2448
Well crystallized, shape-formed, and electrochemically active lithium cobalt oxide (LiCoO2 ) films are electroplated directly on an electron-conducting substrate in an aqueous solution using a soft solution processing that is economical, consumes less energy consuming, and is environmentally friendly. Although LiCoO2 films are easily and economically prepared without any post-synthesis heat treatment, the estimated film properties show a possibility of using the deposited films as a cathode film for lithium rechargeable microbatteries. In addition, the soft solution processing reveals that an exact understanding of chemical reactions and the proper combination of the chemical reactions can create an advanced synthetic procedure. 相似文献
127.
Multimedia processors 总被引:5,自引:0,他引:5
Kuroda I. Nishitani T. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1998,86(6):1203-1221
This paper describes large-scale-integration programmable processors designed for multimedia processing such as real-time compression and decompression of audio and video as well as the generation of computer graphics. As the target of these processors is to handle audio and video in real time, the processing capability must be increased tenfold compared to that of conventional microprocessors, which were designed to handle mainly texts, figures, tables, and photographs. To clarify the advantages of a high-speed multimedia processing capability, we define these chips as multimedia processors. General-purpose microprocessors for workstations and personal computers (PCs) use special built-in hardware for multimedia processing, so the multimedia processors described include these modified general-purpose microprocessors. After reviewing the history of programmable processors, we classify multimedia processors into five categories depending on their basic architecture. The categories are reduced instruction set computer (RISC) microprocessors for workstations, complex instruction set computer microprocessors for PCs, embedded RISCs, low-power digital signal processors (DSPs), which are mainly used for mobile communications devices, and media processors that support PCs for multimedia applications. These five classes are then grouped into two: microprocessors with a multimedia instruction set and highly parallel DSPs. An architectural comparison between these two groups on the basis of Moving Picture Experts Group decoding applications is made, and the advantages and disadvantages of each class are clarified. Future processors, including “system on a chip,” and their applications are also discussed 相似文献
128.
129.
A. V. Akimov A. V. Scherbakov D. R. Yakovlev W. Ossau L. W. Molenkamp Y. Oka I. Souma Y. Terai S. Kuroda K. Takita 《Journal of Superconductivity》2003,16(2):391-394
We use the combination of nonequilibrium phonon and exciton luminescence techniques to study the spin dynamics in diluted magnetic semiconductor structures with (Cd,Mn)Te and (Cd,Mn)Se quantum dots (QDs). We show that the spin–lattice relaxation (SLR) of Mn ions in these structures differs strongly from the SLR in quantum wells. We explain the results by a model where SLR process in structures with QDs is modified by the spin diffusion on Mn ions from the QD to a wetting layer. 相似文献
130.
Phosphorylation is a useful method for improving the functional properties of food proteins. In this article, various methods of phosphorylation are reviewed. Dry-heating phosphorylation, a method developed recently, is also introduced. Some characteristics of phosphate groups are involved, and the effects of phosphorylation on the structural changes, the functional properties, and the physiological functions in vitro of food proteins, are discussed. The types of phosphate linkages and the phosphopeptides from phosphorylated proteins are identified. The molten (partially unfolded) conformations of food proteins formed by phosphorylation are discussed. The phosphorylation of food proteins improved a number of functional properties, including heat stability, emulsifying properties, foaming properties, gelling properties, water absorption capacity, oil absorption capacity, and calcium phosphate-solubilizing ability. In vitro physiological function studies of protein (α-lactoalbumin) indicated that the digestibility (ovalbumin) was improved and the inflammatory response (α-lactoalbumin) was suppressed by phosphorylation. Experiments with animals are necessary to evaluate the toxicity and physiological functions of phosphorylated proteins. 相似文献