全文获取类型
收费全文 | 509篇 |
免费 | 5篇 |
专业分类
电工技术 | 27篇 |
综合类 | 1篇 |
化学工业 | 117篇 |
金属工艺 | 23篇 |
机械仪表 | 15篇 |
建筑科学 | 7篇 |
能源动力 | 22篇 |
轻工业 | 64篇 |
石油天然气 | 1篇 |
无线电 | 34篇 |
一般工业技术 | 101篇 |
冶金工业 | 66篇 |
原子能技术 | 10篇 |
自动化技术 | 26篇 |
出版年
2023年 | 3篇 |
2021年 | 3篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 25篇 |
2012年 | 18篇 |
2011年 | 16篇 |
2010年 | 18篇 |
2009年 | 20篇 |
2008年 | 17篇 |
2007年 | 15篇 |
2006年 | 16篇 |
2005年 | 14篇 |
2004年 | 12篇 |
2003年 | 11篇 |
2002年 | 16篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 18篇 |
1998年 | 21篇 |
1997年 | 24篇 |
1996年 | 15篇 |
1995年 | 19篇 |
1994年 | 19篇 |
1993年 | 12篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 10篇 |
1989年 | 12篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 10篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1967年 | 3篇 |
排序方式: 共有514条查询结果,搜索用时 15 毫秒
31.
Nakamae E. Ishizaki T. Nishita T. Takita S. 《Computer Graphics and Applications, IEEE》1989,9(2):21-29
A method is proposed for compositing 3-D images produced by different programs, taking depth order into consideration. The method can add the following effects to composited images: antialiased images with scaling are displayed by a simple algorithm; the algorithm can add shading effects due to various types of light, such as area sources and skylight; and ray tracing can be performed in localized regions, producing realistic results without the computational expense of ray tracing the whole image. In addition to the above processes, such shading effects as fog and texture mapping can be processed with conventional methods. Thus, it becomes possible to display complex scenes with various shading effects, using relatively small computers. The multiscanning method used for antialiasing and a data structure for processing it are described. Examples are presented to demonstrate the capability of the system 相似文献
32.
33.
Minamida K Sujaya IN Tamura A Shigematsu N Sone T Yokota A Asano K Benno Y Tomita F 《Journal of Bioscience and Bioengineering》2004,98(4):244-250
Di-D-fructofuranose-1,2':2,3'-dianhydride (DFA III) was shown to enhance Ca absorption in rat and human intestine. The effects of DFA III administration (9 g per day for 4 weeks that corresponded to 3-fold the optimal dosage of DFA III) on human intestinal microbiota were studied using denaturing gradient gel electrophoresis (DGGE). The major groups of human intestinal microbiota reported previously: the Bacteroides, the Clostridium coccoides group (Clostridium cluster XIVa), the Clostridium leptum group (Clostridium cluster IV), and the Bifidobacterium group were detected. The similarity of 30 DGGE profiles based on the V3 region (before and after administration to the 15 subjects) of the 16S rDNA were calculated using Pearson's correlation based on numbers, positions and intensity of bands, and then a dendrogram of DGGE profiles was constructed by the unweighted pair group method using arithmetic average (UPGMA) clustering method. By these analyses, no difference in DGGE profiles after DFA III administration was observed in healthy subjects, while two subjects with chronic constipation showed different profiles, namely on numbers, positions and the intensity of some bands. Their stools were softer and stool frequencies increased and they obtained relief from constipation. 相似文献
34.
Martin Patrick Ongol Michiko Tanaka Teruo Sone Kozo Asano 《Food research international (Ottawa, Ont.)》2009,42(8):893-898
A real-time PCR method targeting a gene sequence encoding 16S rRNA processing protein, rimM, for specific detection of Streptococcus thermophilus was developed. The designed real-time PCR primers and probe were specific for S. thermophilus JCM20026, LMG6896, LMG18311, OJT101, OJT102 but not Enteroccocus spp., Lactococcus lactis subsp. lactis, and Streptococcus salivarius which are phylogenetically closely related to S. thermophilus and are difficult to identify using culture-based methods. The linear range of the developed real-time PCR method was from 2.7 to 8.6 log CFU ml?1 with an amplification efficiency of 96%. Minor differences (about 0.4 log CFU ml?1) were observed between counts of S. thermophilus obtained by culture and real-time PCR method in plain yoghurt and yoghurt containing fruits. Therefore, the developed real-time PCR method could be of potential application in specific detection and accurate enumeration of S. thermophilus in a wide range of dairy products. 相似文献
35.
A winding‐current interference model of self‐sensing magnetic bearings (AMBs) and an improvement technique of position‐sensing characteristics are proposed. In the self‐sensing AMB systems, the electromagnets work not only as actuators suspending the rotor but also as position sensors. The self‐sensing position signal, however, includes errors because of nonlinearity of the magnetic circuits. In the proposed model, the current is directly transmitted to the self‐sensing position signal. This transmission means degradation of the self‐sensing characteristics. This winding‐current interference to the self‐sensing signal is reduced by the proposed compensation method. The characteristics of the proposed self‐sensing method agree well with a reference sensor signal up to over 1 kHz. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(2): 70– 77, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20732 Copyright © 2004 Wiley Periodicals, Inc. 相似文献
36.
37.
Positive temperature coefficient of resistivity (PTCR) materials have become very important components, and among these materials
barium titanate compounds make up the most important group. When properly processed these compounds show a high PTCR at the
Curie temperature (the transition temperature from the ferroelectric tetragonal phase to the paraelectric cube phase). In
the first half of this paper literature related to the resistivity-temperature behaviour is discussed. As explained by the
well established Heywang model, the PTCR effect is caused by trapped electrons at the grain boundaries. From reviewing experimental
results in the literature it is clear that the PTCR effect can not be explained by assuming only one kind of electron trap.
It is concluded that as well as barium vacancies, adsorbed oxygen as 3d-elements can act as electron traps. In the second
half of this paper, the influence of the processing parameters on the PTCR related properties is discussed. Special emphasis
is placed on the phenomenon that the conductivity and grain size decrease abruptly with increasing donor concentration above
∼ 0.3 at%. Several models explaining this phenomenon are discussed and apparent discrepancies in experimental data are explained. 相似文献
38.
Infrared thermography (IRT) and ultraviolet fluorescence (UVF) for the nondestructive evaluation of ballast tanks’ coated surfaces 总被引:1,自引:0,他引:1
Mohammed A. Omar Belal Gharaibeh Abraham J. Salazar Kozo Saito 《NDT & E International》2007,40(1):62-70
This paper quantifies the detectability limits of infrared thermography (IRT) and ultraviolet fluorescence (UVF) techniques in the thickness measurements of the naval protective coatings applied on ship ballast tanks. The change in signal per unit thickness (25 μm) is used to describe each technique resolution, when using a pulsed-thermographic procedure and a UVF spectroscopic analysis. Furthermore, Tanimoto criterion in addition to a local signal-to-noise ratio (SNR) computation measure the revealability of pinholes, the IRT technique provides an 83% revealability while the UVF imaging has a 66% value. The goal of this work is to benchmark the novel UVF approach against that of the IRT procedures. 相似文献
39.
J Ishizaki K Meguro H Ambo M Shimada S Yamaguchi C Hayasaka H Komatsu Y Sekita A Yamadori 《Canadian Metallurgical Quarterly》1998,53(6):P359-P363
We investigated community-based data of the Mini-Mental State Examination (MMSE) scores of elderly residents along with the effects of age and educational level. MMSE was planned for all residents over 65 years of age in a town in northern Japan. The number of elders who took the MMSE was 2,266 (90%). The score significantly declined with age and lower educational level, although no effect of sex was apparent. For the MMSE subitems, all the values except for that of naming showed effects of both age and educational level. Those screened by MMSE who fell in the range of cognitive impairment (< 24) accounted for 21.8% and those with severe cognitive impairment (< 18) constituted 6.0%. Despite the differences in language and culture, the mean scores are remarkably similar between Japan and other countries. This is the first normative, community-based study of MMSE among elderly adults in Japan. 相似文献
40.
Phase Diagram of the BaO-CuO Binary System 总被引:1,自引:0,他引:1
The phase diagram of the BaO-CuO binary system has been investigated in air and in a mixed gas of Ar + 0.21 atm of O2 . The existence of two compounds, BaCuO2 and Ba2 CuO3 , was confirmed. The phase transition of Ba2 CuO3 from an orthorhombic to a tetragonal phase was observed to occur at 1083 K. The lattice constants of the tetragonal Ba2 CuO3 phase were determined to be a = 1.2975 nm and b = 0.3992 nm. BaCuO2 was shown to melt incongruently by a synthetic reaction at 1289 K. Furthermore, the existence of two eutectic reactions and a peritectic reaction in the present system was confirmed. 相似文献