全文获取类型
收费全文 | 1108篇 |
免费 | 25篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 68篇 |
综合类 | 5篇 |
化学工业 | 313篇 |
金属工艺 | 50篇 |
机械仪表 | 28篇 |
建筑科学 | 26篇 |
矿业工程 | 1篇 |
能源动力 | 50篇 |
轻工业 | 75篇 |
水利工程 | 1篇 |
无线电 | 61篇 |
一般工业技术 | 189篇 |
冶金工业 | 116篇 |
原子能技术 | 53篇 |
自动化技术 | 106篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 13篇 |
2019年 | 12篇 |
2018年 | 17篇 |
2017年 | 12篇 |
2016年 | 16篇 |
2015年 | 17篇 |
2014年 | 16篇 |
2013年 | 50篇 |
2012年 | 42篇 |
2011年 | 70篇 |
2010年 | 34篇 |
2009年 | 40篇 |
2008年 | 43篇 |
2007年 | 42篇 |
2006年 | 47篇 |
2005年 | 42篇 |
2004年 | 32篇 |
2003年 | 33篇 |
2002年 | 26篇 |
2001年 | 26篇 |
2000年 | 27篇 |
1999年 | 36篇 |
1998年 | 62篇 |
1997年 | 42篇 |
1996年 | 38篇 |
1995年 | 18篇 |
1994年 | 25篇 |
1993年 | 16篇 |
1992年 | 13篇 |
1991年 | 21篇 |
1990年 | 11篇 |
1989年 | 14篇 |
1988年 | 9篇 |
1987年 | 13篇 |
1986年 | 17篇 |
1985年 | 13篇 |
1984年 | 20篇 |
1983年 | 13篇 |
1982年 | 15篇 |
1981年 | 11篇 |
1980年 | 7篇 |
1979年 | 15篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1976年 | 13篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有1142条查询结果,搜索用时 15 毫秒
51.
Yoshinori Suzuki Takashi Uchida Masataka Wakihara Masao Taniguchi 《Materials Research Bulletin》1981,16(9):1085-1090
Changing the partial pressure of sulfur Ps2 at temperatures of 750° and 950°C, phase equilibria on the Mo-S system by solid-gas reaction were investigated. Hexagonal 2H-MoS2 and monoclinic Mo2S3 phases were identified from the x-ray powder diffraction pattern. The 2H-MoS2 had a slight homogeneity range, i.e. MoS1.978 to MoS2.0 at 950°C, MoS1.983 to MoS2.0 at 750°C. No remarkable variation of lattice parameters for the MoS2 was observed. The composition of the Mo2S3 phase was not stoichiometric MoS1.5 but MoS1.457 at 950°C. At 750°C the composition of the Mo2S3 phase could not be determined since it was quite difficult to establish the equilibrium state between the gas and the condensed phases. This finding agreed well with the result of Morimoto and Kullerud. 相似文献
52.
Illumination normalization with time-dependent intrinsic images for video surveillance 总被引:1,自引:0,他引:1
Matsushita Y Nishino K Ikeuchi K Sakauchi M 《IEEE transactions on pattern analysis and machine intelligence》2004,26(10):1336-1347
Variation in illumination conditions caused by weather, time of day, etc., makes the task difficult when building video surveillance systems of real world scenes. Especially, cast shadows produce troublesome effects, typically for object tracking from a fixed viewpoint, since it yields appearance variations of objects depending on whether they are inside or outside the shadow. In this paper, we handle such appearance variations by removing shadows in the image sequence. This can be considered as a preprocessing stage which leads to robust video surveillance. To achieve this, we propose a framework based on the idea of intrinsic images. Unlike previous methods of deriving intrinsic images, we derive time-varying reflectance images and corresponding illumination images from a sequence of images instead of assuming a single reflectance image. Using obtained illumination images, we normalize the input image sequence in terms of incident lighting distribution to eliminate shadowing effects. We also propose an illumination normalization scheme which can potentially run in real time, utilizing the illumination eigenspace, which captures the illumination variation due to weather, time of day, etc., and a shadow interpolation method based on shadow hulls. This paper describes the theory of the framework with simulation results and shows its effectiveness with object tracking results on real scene data sets. 相似文献
53.
In our real-world applications, data may be imprecise in which levels or degrees of preciseness of data are intuitively different. In this case, fuzzy set expressions are considered as an alternative to represent the imprecise data. In general, the degree of similarity relationship between two fuzzy (imprecise) data in real-world applications may not necessarily be symmetric or transitive. In order to provide such a degree of similarity between two fuzzy data, we introduced the fuzzy conditional probability relation. The concept of a fuzzy conditional probability relation may be considered as a concrete example of weak similarity relation which in turn is a special type of fuzzy binary relation generalizing similarity relation. Two important applications concerning the application of Knowledge Discovery and Data Mining (KDD) in the presence of a fuzzy data table (usually called fuzzy information system), namely removing redundant objects and recognizing partial or total dependency of (domain) attributes, are considered induced by the fuzzy conditional probability relation. Here, the fuzzy information system contains precise as well as imprecise data (fuzzy values) about objects of interest characterized by some attributes. Related to the dependency of attributes, we introduce the fuzzy functional dependency that satisfies Armstrongs Axioms. In addition, we also discuss some interesting applications such as approximate data reduction and projection, approximate data querying and approximate joining in order to extend the query system. 相似文献
54.
Taiji?Sugiyama Noriyasu?Homma Kenichi?Abe Masao?SakaiEmail author 《Artificial Life and Robotics》2004,7(4):156-159
We have developed a novel pulse-coupled neural network (PCNN) for speech recognition. One of the advantages of the PCNN is
in its biologically based neural dynamic structure using feedback connections. To recall the memorized pattern, a radial basis
function (RBF) is incorporated into the proposed PCNN. Simulation results show that the PCNN with a RBF can be useful for
phoneme recognition.
This work was presented in part at the 7th International Symposium on Artificial Life and Robotics, Oita, Japan, January 16–18,
2002 相似文献
55.
Yoshihira Okanda Masao Fukusumi Soji Nenno John B. Newkirk 《Metallurgical and Materials Transactions A》1983,14(10):2131-2142
High temperature corrosion tests in 80 pct Na2SO4-20 pct NaCI were made on five Fe-30 wt pct Cr-5 wt pct Al alloys containing various amounts of cerium up to 0.68 pct. After the corrosion tests, samples were examined metallographically and by X-ray diffraction and X-ray microanalysis. It was found that the surface scale formed on each sample decreased in thickness as the Ce content increased. Electron probe microanalyses suggest that this retarding behavior is related to the early formation of a Ce-induced protective scale of α-Al2O3. The role of Ce in promoting the formation of the α-Al2O3 scale is discussed. 相似文献
56.
57.
Koichiro Koyama Masao Morishita Tomohiro Harada Nobuyuki Maekawa 《Metallurgical and Materials Transactions B》2003,34(5):653-659
The standard Gibbs energies of formation of Fe2Mo3O12, Fe2Mo3O8, FeMoO4, and Fe2MoO4 of the Fe-Mo-O ternary system and the μ phase of the Fe-Mo binary system have been determined by measuring electromotive forces of galvanic cells having an Y2O3-stabilized ZrO2 solid electrolyte. The results are as follows: $$\begin{gathered} \Delta _f G^\circ (FeMoO_4 )/kJ \cdot mol^{ - 1} = - 1053.5 + 0.2983(T/K) \pm 0.4 \hfill \\ Temperature range: 1112 to 1339 K \hfill \\ \Delta _f G^\circ (Fe_2 Mo_3 O_8 )/kJ \cdot mol^{ - 1} = - 2347 + 0.6814(T/K) \pm 1 \hfill \\ Temperature range: 1112 to 1339 K \hfill \\ \Delta _f G^\circ (Fe_2 Mo_3 O_{12} )/kJ \cdot mol^{ - 1} = - 2993 + 0.9105(T/K) \pm 2 \hfill \\ Temperature range: 1040 to 1145 K \hfill \\ \Delta _f G^\circ (Fe_{0.58} Mo_{0.42} )/kJ \cdot mol^{ - 1} = - 18.7 + 0.0117(T/K) \pm 0.1 \hfill \\ Temperature range: 1162 to 1223 K \hfill \\ \Delta _f G^\circ (Fe_2 MoO_4 )/kJ \cdot mol^{ - 1} = - 1174 + 0.342(T/K) \pm 1 \hfill \\ Temperature range: 1243 to 1466 K \hfill \\ \end{gathered} $$ where the standard pressure is 1 bar (100 kPa). 相似文献
58.
Suzuki I Yamada K Yamakawa T Hashiba M Akazawa K 《Computer methods and programs in biomedicine》2003,70(3):253-258
We developed a low cost, user-friendly multimedia delivery system, to provide medical lectures saved as multimedia contents to persons engaged in medicine. This system was created using the RealSystem package with the TCP/IP network. Users can review lectures and medical meeting presentations with video and audio through the Internet, whenever convenient. Each medical source of video and slide has been clearly displayed on a screen. Members of medical associations or medical students can easily review the most interesting parts of these files. This system is being used efficiently in distance learning and aids the diffusion of the latest information and technology to busy physicians and medical students. 相似文献
59.
A variable-pressure scanning electron microscopy (VP-SEM) with a cooling stage permits long hours of observation of water-containing specimens in their natural or close to natural state, without the conventional specimen preparations of fixation, dehydration, drying and metal coating. It reduces water vaporization and beam damage by keeping the specimens at a low temperature. We observed Bacillus cereus colonies on nutrient agar, which would shrink significantly if any conventional specimen preparation technique were used. We also studied the growing process of the bacteria on raw and steamed rice using the VP-SEM without conventional preparation techniques. Original specimens were directly mounted onto specimen holders and their backscattered electron images observed under the following conditions: specimen stage temperature, -10 degrees C; specimen chamber vacuum level, 30-70 Pa; and accelerating voltage, 15-20 kV. We recognized that the VP-SEM minimized deformation of the colonies due to shrinkage of the nutrient agar, and successfully imaged the morphology of the colonies and bacteria without a decline in bacteria number, which is apt to occur during fixation and dehydration. Also, the growth process of the bacteria on raw or steamed rice could be observed promptly, since there is no specimen preparation step. 相似文献
60.
Sutrisno A Ueda M Inui H Kawaguchi T Nakano Y Arai M Miyatake K 《Journal of Bioscience and Bioengineering》2001,91(6):599-602
A gene encoding chitinase from Aeromonas sp. no. 10S-24 was expressed using pTrc99A in Escherichia coli JM 105 which yielded a 5-fold higher activity than when pUC19 was used. Three different truncated enzymes (SA-1, SA-2 and SA-3) were obtained after purification. Their isoelectric points were 7.0, 6.9, and 6.7, respectively. The enzymes showed two optimum pHs, 4.0 and 7.0, when incubated with ethylene glycol chitin as the substrate, and were stable over a wide pH range (3.0-9.0). The optimum temperature was 60 degrees C and the enzymes were stable up to 50 degrees C. The chitinases exhibited wide substrate specificities for chitin-related compounds. 相似文献