全文获取类型
收费全文 | 1047篇 |
免费 | 29篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 41篇 |
综合类 | 1篇 |
化学工业 | 250篇 |
金属工艺 | 19篇 |
机械仪表 | 33篇 |
建筑科学 | 9篇 |
能源动力 | 29篇 |
轻工业 | 77篇 |
水利工程 | 2篇 |
无线电 | 154篇 |
一般工业技术 | 197篇 |
冶金工业 | 165篇 |
原子能技术 | 35篇 |
自动化技术 | 66篇 |
出版年
2023年 | 8篇 |
2022年 | 16篇 |
2021年 | 24篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 27篇 |
2017年 | 11篇 |
2016年 | 17篇 |
2015年 | 10篇 |
2014年 | 29篇 |
2013年 | 50篇 |
2012年 | 36篇 |
2011年 | 35篇 |
2010年 | 33篇 |
2009年 | 36篇 |
2008年 | 35篇 |
2007年 | 30篇 |
2006年 | 28篇 |
2005年 | 37篇 |
2004年 | 34篇 |
2003年 | 44篇 |
2002年 | 33篇 |
2001年 | 24篇 |
2000年 | 22篇 |
1999年 | 27篇 |
1998年 | 76篇 |
1997年 | 41篇 |
1996年 | 32篇 |
1995年 | 33篇 |
1994年 | 31篇 |
1993年 | 34篇 |
1992年 | 19篇 |
1991年 | 12篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 5篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有1078条查询结果,搜索用时 15 毫秒
81.
T. Yaeshima S. Takahashi N. Ishibashi S. Shimamura 《International journal of food microbiology》1996,30(3):303-313
Sixteen strains of Bifidobacterium isolated from 15 dairy products such as yogurt, cultured milk, butter and cheese were characterized on the basis of phenotypic characteristics and DNA similarities were examined by a microplate hybridization method. Three of the strains were identified as Bifidodobacterium longum, one strain was identified as Bifidobacterium bifidm, and one strain was assigned to the species Bifidobacterium breve on the basis of phenotypic characteristics, and this identification was confirmed by the analysis of DNA similarities. The remaining 11 strains could not be identified by examining their phenotypic characteristics and, contrary to the product label information, these strains were identified as Bifudidobacterium animalis on the basis of DNA similarities. The applicability of the colorimetric hybridization method in micro dilution wells to genetic identification of Bifidobacterium species was also studied. 相似文献
82.
A new three-phase current-fed soft-switching PWM converter is presented. This converter utilises two types of switching commutation scheme to improve the PWM current utilisation rate. It is shown by means of computer simulation that this converter has low THD and offers unity power factor correction 相似文献
83.
84.
85.
A monolayer of dodecanethiol-stabilized gold nanoparticles changed into two-dimensional and three-dimensional self-organized structures by annealing at 323 K. Subsequent crystal growth of gold nanoparticles occurred. Thiol molecules, although chemisorbed, form relatively unstable bonds with the gold surface; a few thiols desorbed from the surface and oxidized to disulfides at 323 K, because the interaction energy between thiol macromolecules is larger than that between a thiol and a nanoparticle. The gold nanoparticles approached each other and grew into large single or twinned crystals because of the van der Waals attraction and the heat generated by the exothermic formation of disulfides. 相似文献
86.
Sasaki K. Ishibashi K. Shimohigashi K. Yamanaka T. Moriwake N. Honjo S. Ikeda S. Koike A. Meguro S. Minato O. 《Solid-State Circuits, IEEE Journal of》1990,25(5):1075-1081
A 4-Mb CMOS SRAM having 0.2-μA standby current at a supply voltage of 3 V has been developed. Current-mirror/PMOS cross-coupled cascade sense-amplifier circuits have achieved the fast address access time of 23 ns. A new noise-immune data-latch circuit has attained power-reduction characteristics at a low operating cycle time without access delay. A 0.5-μm CMOS, four-level poly, two-level metal technology with a polysilicon PMOS load memory cell, yielded a small cell area of 17 μm2 and the very small standby current. A quadruple-array, word-decoder architecture allowed a small chip area of 122 mm2 相似文献
87.
Development and applications of an analytical electron microscope with a field emission electron gun
A. Koreeda T. Ishibashi K. Shimizu M. Tomita C. Kimura H. Okano 《Materials Characterization》1990,25(4):375-395
An analytical electron microscope with a field emission electron gun has been developed in order to improve the function of material identification, in order to obtain higher resolution of images, sharper electron diffraction patterns, and purer x-ray spectra with no effects of contamination from smaller areas than in the conventional instruments so far utilized. The performance capabilities of this newly developed analytical electron microscope, the Model H-600FE, have been examined and found to be very useful for the material characterization of nanometer-size areas. Various attributes of the microscope became apparent with reference to the results of different studies. These include better convergence of the electron beam (demonstrated by examination of an MoS2 thin film), high-resolution transmission electron microscopy (using a gold film), high-resolution scanning electron microscopy (with a carbon film containing nanometer-size holes), high-angle resolution electron diffraction (of an iron carbide film), and precision x-ray analysis of nanometer-size areas (using a pyroxene crystal and a Cu---Zn---Al shape memory alloy). 相似文献
88.
16S ribosomal DNA sequences of various strains of Phormidium tenue (P. tenue) in Lake Kamafusa were determined. Such P. tenue could not be distinguished under microscopic examination. From the results of the analyses of base sequences, and using a phylogenetic tree, several P. tenue with different species specificity on the sequence were found in the lake. P. tenue were divided into three groups. The first produced 2-methylisoborneol (MIB) and was close to a species from the moat of Nagoya castle. The second produced MIB and was characteristic of Lake Kamafusa. The third had a brown color like a Lake Biwa strain and was MIB non-producing. From the phylogenetic tree, it was revealed that species had not changed recently by mutation. Moreover, a detection method for P. tenue by PCR and dot hybridization was established. 相似文献
89.
Tohru Sugiyama Yoshiaki Kudo Youichi Takayama 《Journal of the Society for Information Display》2009,17(1):29-35
Abstract— Soft proofing, which can confirm the color reproduction of printed matter on a monitor, is coming into wide use in the field of graphic arts. However, there is a problem in that the color on the monitor looks different from that of printed matter, even though the L*a*b* value of the monitor's white point has been adjusted to that of the paper by using a spectroradiometer. After the color rendition of an LCD is visually adjusted to that of the paper, the measured color of the LCD shows color with L*a*b* values corresponding to a more greenish‐blue white than that of paper. For CRTs, this corresponds to a more bluish‐white. In this paper, it was assumed that bright lines in the measured spectrums of the monitors and the illuminations spread to the next wavelength band by the optical systems of the spectroradiometer. To solve the problem, a method is proposed to enhance the bright line by using a three‐tap digital filter. The effect of this method on two types of monitors under three types of illumination is also reported. After enhancing the bright lines, ΔE between the monitor and paper becomes smaller than that for the original one. 相似文献
90.