全文获取类型
收费全文 | 241篇 |
免费 | 9篇 |
专业分类
电工技术 | 13篇 |
化学工业 | 63篇 |
金属工艺 | 8篇 |
机械仪表 | 3篇 |
建筑科学 | 3篇 |
矿业工程 | 1篇 |
能源动力 | 20篇 |
轻工业 | 21篇 |
无线电 | 4篇 |
一般工业技术 | 59篇 |
冶金工业 | 37篇 |
原子能技术 | 2篇 |
自动化技术 | 16篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 11篇 |
2012年 | 10篇 |
2011年 | 12篇 |
2010年 | 12篇 |
2009年 | 16篇 |
2008年 | 13篇 |
2007年 | 15篇 |
2006年 | 10篇 |
2005年 | 4篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 9篇 |
1998年 | 10篇 |
1997年 | 10篇 |
1996年 | 14篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 3篇 |
1972年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有250条查询结果,搜索用时 46 毫秒
91.
S Nishizaki N Kobayashi S Furutani T Arai Y Shiwaku 《Canadian Metallurgical Quarterly》1976,25(2):198-207
A variety of factors, including concentration of oil, antibiotics, dyes, and inoculum washes, were examined to determine their effect on the total counts of microorganisms on oil-containing media. The media found to be best for enumerating petroleum-degrading microorganisms contained 0.5% (vol/vol) oil and 0.003% phenol red, with Fungizone added for isolating bacteria and streptomycin and tetracycline added for isolating yeasts and fungi. Washing the inoculum did not improve recovery of petroleum degraders. Specifically, silica gel-oil medium and a yeast medium are recommended for enumeration of petroleum-degrading bacteria and yeasts and fungi, respectively. It is suggested that counts of petroleum degraders be expressed as percentage of the total population rather than total numbers of petroleum degraders per se. Incubation temperature and presence of oil was found to influence the numbers of petroleum-degrading microorganisms at a given sampling site. 相似文献
92.
T. Noji T. Takabayashi T. Nishizaki N. Kobayashi Y. Koike 《Journal of Low Temperature Physics》1996,105(3-4):533-538
We have found clear anisotropy in the ab plane with fourfold symmetry of the resistive superconducting transition under magnetic fields for single-crystal Pb2Sr2Y0.62Ca0,38Cu3O8, which is regarded as anisotropy of the upper critical field Hc2. This is not only qualitatively but also quantitatively similar to that formerly observed in La1.86Sr0.14CuO4. The observed fourfold symmetry is explained as being mainly due to the anisotropy of the superconducting energy gap owing to
pairing. Hc2, one of the bulk properties, supports
pairing in the high-Tc superconductivity. 相似文献
93.
ABSTRACT In this article, we present a method for obtaining Stackelberg solutions to two-level integer problems through genetic algorithms, which have received much attention as a promising computational method for complex problems. Assuming that there exist the upper- and the lower-bounds constraints with respect to integer variables, we employ a zero-one bit string as an individual in our artificial genetic systems. It is required that each individual satisfies the constraints of the given problem and a response of the lower level decision maker with respect to a decision that the upper level decision maker is rational. Therefore, individuals not satisfying the two conditions are penalized in the artificial genetic systems. To demonstrate the feasibility and efficiency of the proposed methods, computational experiments are carried out and comparisons between the Moore and Bard method based on the branch-and-bound techniques and the proposed methods are provided. 相似文献
94.
Ichiro Nishizaki Masatoshi Sakawa Hideki Katagiri 《Applied Artificial Intelligence》2013,27(7):651-671
In this paper, by simulations on an artificial social model, we analyze cooperative behavior of agents playing the prisoner's dilemma game, in which each of the agents has the two strategies: cooperate and defect. Because defect yields a better payoff whichever strategy an opponent chooses, it is rational for an agent to choose defect in a single game or a finite number of games. However, it is known that a pair of cooperates can also be a Nash equilibrium pair if the players do not know when the game is over or the game is infinitely repeated. To investigate such cooperative behavior, we employ an artificial social model called the Sugarscape and carry out simulations on the model. Arranging three kinds of environments in the Sugarscape, we examine cooperative behavior of agents who are essentially selfish, in a sense that they maximize their payoffs, and investigate influence of environmental changes on the cooperative behavior. 相似文献
95.
Hiroaki Onuma Itaru Yamashita Kazumi Serizawa Hiroaki Tanno Ai Suzuki Hideyuki Tsuboi Nozomu Hatakeyama Akira Endou Hiromitsu Takaba Momoji Kubo Hiroshi Kajiyama Akira Miyamoto 《Journal of the Society for Information Display》2010,18(4):301-309
Abstract— The relationship between crystal structures and emission properties has been computationally investigated for Eu2+‐doped phosphors. The electronic structure of the Eu2+‐doped BaMgAl10O17 phosphor was analyzed by using the quantum chemistry method. The different effects of O and Ba atoms on the Eu 5d states were determined. The presence of O and Ba atoms increases and decreases the energy level of the Eu 5d orbital by forming anti‐bonding and bonding interactions, respectively. According to the electronic‐structure analysis, the structure index that represents the local geometrical information of the Eu atom was defined. The relationship between the crystal structures and the emission wavelengths of the 1 6 Eu2+‐doped oxide phosphors were studied by using the quantitative structure‐property relationship (QSPR). The QSPR model suggested that the both O and alkaline‐earth atoms around the Eu atom are of importance in the determination of the emission wavelength. The interaction between the Eu and the nearest O atoms make the Eu2+ emission wavelength short. On the other hand, the interaction from the alkaline‐earth atoms around the Eu atom lengthens the Eu2+emission wavelength. This evaluation method is useful in selecting the host material that indicates a desirable emission wavelength of the Eu2+‐doped phosphors. 相似文献
96.
Common soda lime slide glass substrates made by floating molten glass on the surface of molten tin contain a tin-diffused layer that is demonstrated to be a low-loss polarization-insensitive slab optical waveguide. In this study, such a tin-diffused waveguide was locally covered with a tapered thin TiO2 film to form a composite structure in which the zeroth-order transverse electric (TE0) and magnetic (TM0) modes are spatially separated from each other. This feature enables the composite structure to serve as a highly sensitive polarimetric interferometer. Moreover, a negligible modal birefringence of tin-diffused waveguides offers the polarimetric interferometer an improved performance relative to those fabricated earlier using single-mode potassium ion-exchanged glass waveguides. In situ detection of both the protein adsorption and a small change in refractive index of liquid was accomplished using the tin-diffused waveguide-based polarimetric interferometer. With horse heart myoglobin, adsorption from aqueous solution less than 0.125 monolayer coverage can cause the interferometer to yield a phase-difference change of delta phi = 2pi. 相似文献
97.
In mutualisms, partner discrimination is often the most important challenge for interacting organisms. The interaction between ants and aphids is a model system for studying mutualisms; ants are provided with honeydew by aphids and, in turn, the ants offer beneficial services to the aphids. To establish and maintain this system, ants must discriminate mutualistic aphid species correctly. Although recent studies have shown that ants recognize aphids as mutualistic partners based on their cuticular hydrocarbons (CHCs), it was unclear which CHCs are involved in recognition. Here, we tested whether the n-alkane or methylalkane fraction, or both, of aphid CHCs were utilized as partner recognition cues by measuring ant aggressiveness toward these fractions. When workers of Tetramorium tsushimae ants were presented with dummies coated with n-alkanes of their mutualistic aphid Aphis craccivora, ants displayed higher levels of aggression than to dummies treated with total CHCs or methyl alkanes of A. craccivora; responses to dummies treated with n-alkanes of A. craccivora were similar to those to control dummies or dummies treated with the CHCs of the non-mutualistic aphid Acyrthosiphon pisum. By contrast, ants exhibited lower aggression to dummies treated with either total CHCs or the methylalkane fraction of the mutualistic aphid than to control dummies or dummies treated with CHCs of the non-mutualistic aphid. These results suggest that T. tsushimae ants use methylalkanes of the mutualistic aphid’s CHCs to recognize partners, and that these ants do not recognize aphids as partners on the basis of n-alkanes. 相似文献
98.
Using a theory based on a modified Stokes' law equation, the settling behavior of fillers was investigated (glass beads and silica powder) in thermosetting epoxy casting resins during cure. In this study a suspension (a thermosetting epoxy casting resin) containing a large amount of filler particles is assumed to be a homogeneous fluid, and the settling phenomena are treated such that one or more particles of the filler settle into the homogeneous fluid under gravity without interference from other particles. The viscosity increase of the fluid during cure is taken into consideration. The experimental results agree well with the theoretical predictions when the settling distances are small and the particle size distribution is narrow. When these conditions are not satisfied, various effects are observed such as convection, filtering, combination, bottom effect, and a broad particle size distribution. In addition, the formation of a compression zone and of a compaction zone are clearly observed. 相似文献
99.
Nano-sized Li4Ti5O12 powders with high dispersivity were fabricated by a sol-gel process using P123 as surfactant, which exhibited much better high rate performance towards Li+ insertion/extraction as compared to the densely aggregated Li4Ti5O12 particles although the primary grain sizes of both samples were almost the same. The Li4Ti5O12 electrode prepared from the well-dispersed nanopowders can preserve 88.6% of the capacity at 0.1 A g−1 when being cycled at 1 A g−1, which is obviously higher than that of the densely aggregated sample, in which only 30% capacity can be retained. By improving the dispersivity, the specific surface area of the Li4Ti5O12 nanoparticles, hence the electrode-electrolyte contact area was increased; meanwhile, more homogeneous mixing of the active materials with carbon black was achieved. All these factors might have resulted in the better high rate performance. 相似文献
100.
T Nishizaki S Ozaki K Harada H Ito H Arai T Beppu K Sasaki 《Canadian Metallurgical Quarterly》1998,21(4):340-346
A method of induction of multiple DNA-protein and protein-protein cross-links in chromatin of isolated nuclei has been developed. The cross-linking is brought about by mutual effect of fluorochrome ethidium bromide (EtBr) and irradiation with blue light. Electron microscopic analysis of nuclei isolated in solutions with various concentrations of divalent cations, stained with EtBr and irradiated with blue light, has demonstrated that the method leads to a selective stabilization of macromolecular complexes of chromatin against various treatments causing decompactization of native chromatin. Besides that, the stabilization of nucleoli and clusters of interchromatin granules takes place. On the other hand, the same treatment does not stabilize elementary chromatin fibers (about 30 nm thick), and the transition to the nucleosomal fiber occurs after extraction of histone H1 with 0.6 M NaCl. Electrophoretic analysis of proteins from control and irradiated nuclei shows the basic role of non-histone proteins in the stabilization. The data are discussed based on the assumption on the availability of some "intermediate" levels of chromatin compaction between 30 nm chromatin fiber and mitotic chromosome. 相似文献