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91.
Effects of annealing in an oxygen ambient on electrical properties of ohmic contacts to p-type GaN 总被引:3,自引:0,他引:3
Yasuo Koide T. Maeda T. Kawakami S. Fujita T. Uemura N. Shibata Masanori Murakami 《Journal of Electronic Materials》1999,28(3):341-346
Effects of annealing ambient of an oxygen and nitrogen mixed gas on the electrical properties were studied for Au-based ohmic
contacts (NiAu, CoAu, CuAu, PdAu, and PtAu) to p-type GaN. Addition of oxygen to the nitrogen gas reduced the specific contact
resistances (ρc) and resitivities of the p-GaN epilayers (ρs) of the contacts after annealing at temperatures of 500–600°C. The microstructural analysis at the p-GaN/metal interfaces
did not detect the heterostructural intermediate semiconductor layer at the GaN/metal interfaces. The reason for reduction
of both the ρc and ρs values by the oxygen gas addition was believed to be due to formation of the p-GaN epilayer with high hole concentrations,
caused by removal of hydrogen atoms which bonded with Mg atoms. 相似文献
92.
MR Zile M Koide H Sato Y Ishiguro CH Conrad JM Buckley JP Morgan G Cooper 《Canadian Metallurgical Quarterly》1999,33(1):250-260
OBJECTIVES: We sought to determine whether the ameliorative effects of microtubule depolymerization on cellular contractile dysfunction in pressure overload cardiac hypertrophy apply at the tissue level. BACKGROUND: A selective and persistent increase in microtubule density causes decreased contractile function of cardiocytes from cats with hypertrophy produced by chronic right ventricular (RV) pressure overloading. Microtubule depolymerization by colchicine normalizes contractility in these isolated cardiocytes. However, whether these changes in cellular function might contribute to changes in function at the more highly integrated and complex cardiac tissue level was unknown. METHODS: Accordingly, RV papillary muscles were isolated from 25 cats with RV pressure overload hypertrophy induced by pulmonary artery banding (PAB) for 4 weeks and 25 control cats. Contractile state was measured using physiologically sequenced contractions before and 90 min after treatment with 10(-5) mol/liter colchicine. RESULTS: The PAB significantly increased RV systolic pressure and the RV weight/body weight ratio in PAB; it significantly decreased developed tension from 59+/-3 mN/mm2 in control to 25+/-4 mN/mm2 in PAB, shortening extent from 0.21+/-0.01 muscle lengths (ML) in control to 0.12+/-0.01 ML in PAB, and shortening rate from 1.12+/-0.07 ML/s in control to 0.55+/-0.03 ML/s in PAB. Indirect immunofluorescence confocal microscopy showed that PAB muscles had a selective increase in microtubule density and that colchicine caused complete microtubule depolymerization in both control and PAB papillary muscles. Microtubule depolymerization normalized myocardial contractility in papillary muscles of PAB cats but did not alter contractility in control muscles. CONCLUSIONS: Excess microtubule density, therefore, is equally important to both cellular and to myocardial contractile dysfunction caused by chronic, severe pressure-overload cardiac hypertrophy. 相似文献
93.
94.
Hirofumi Koike Minoru Morikawa Hideki Ishimaru Reiko Ideguchi Masataka Uetani Takeshi Hiu Takayuki Matsuo Mitsuharu Miyoshi 《International journal of molecular sciences》2022,23(17)
Vestibular schwannomas are the most common tumor at the common cerebellopontine angle, followed by meningiomas. Differentiation of these tumors is critical because of the different surgical approaches required for treatment. Recent studies have demonstrated the utility of amide proton transfer (APT)-chemical exchange saturation transfer (CEST) imaging in evaluating malignant brain tumors. However, APT imaging has not been applied in benign tumors. Here, we explored the potential of APT in differentiating between schwannomas and meningiomas at the cerebellopontine angle. We retrospectively evaluated nine patients with schwannoma and nine patients with meningioma who underwent APT-CEST MRI from November 2020 to April 2022 pre-operation. All 18 tumors were histologically diagnosed. There was a significant difference in magnetization transfer ratio asymmetry (MTRasym) values (0.033 ± 0.012 vs. 0.021 ± 0.004; p = 0.007) between the schwannoma and meningioma groups. Receiver operative curve analysis showed that MTRasym values clearly differentiated between the schwannoma and meningioma groups. At an MTRasym value threshold of 0.024, the diagnostic sensitivity, specificity, positive predictive value, and negative predictive values for MTRasym were 88.9%, 77.8%, 80.0%, and 87.5%, respectively. Our results demonstrated the ability of MTRasym values on APT-CEST imaging to discriminate patients with schwannomas from patients with meningiomas. 相似文献
95.
Makiko YONAMINE Takanori USHIJIMA Yoshiaki MIYAZATO Mitsuharu MASUDA Hiroshi KATANODA Kazuyasu MATSUO 《热科学学报(英文版)》2006,15(2):135-139
In this paper, the characteristics of a pressure wave propagating against two parallel subsonic streams in a constant-area straight duct are investigated by one-dimensional analysis, two-dimensional numerical simulation, and experiments. Computations have been carried out by the two-dimensional Euler Equations using the Chakravarthy-Osher-type TVD scheme. Optical observations by the schlieren method as well as wall pressure measurements have been performed to clarify both the structure and the propagation velocity of pressure waves. The results show that the pressure wave propagating against the streams changes into a bifurcated pressure wave and the bifurcation occurs in the low speed streams. It is also found that the propagation velocity of the pressure wave obtained by the analysis and computation agrees well with the present experimental data. 相似文献
96.
97.
Toshio Koide Haruki Kubo Hitoshi Watanabe 《International Journal of Circuit Theory and Applications》2004,32(6):447-470
Aiming at establishing a firm basic theory to ring‐based information network management systems, our paper proposes a tie‐set graph theory. We define a binary vector representing a tie‐set in a biconnected undirected graph G=(V,E) as a tie‐set vector. The set of tie‐set vectors forms a vector space over the proposed law of composition, then a basis of the vector space, μ linear independent tie‐set vectors, is defined as a tie‐set basis. The essential key concept in our theory is a tie‐set graph, which has a one‐to‐one correspondence to a tie‐set basis and represents a relation between two tie‐set vectors of the basis. Some important properties of tie‐set graphs and their application to survivable mesh networks in modern high‐speed backbone networks are also presented. Furthermore, as a general approach to network flow optimization problems, tie‐set flow vector space is proposed based on the tie‐set graph theory. A distributed algorithm for the network flow optimization problems and its application are also presented in this paper. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
98.
Wakamatsu M. Kato K. Inoue N. Koide H. Okubo H. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2003,10(6):942-947
An insulating oil/pressboard (PB) composite insulation is generally utilized in oil-immersed power transformers. In such a transformer, charges accumulate at oil/PB interface which changes the electric field distribution depending on time and oil condition. In this paper, we report on directly measured dc electric field in oil/PB composite insulation system using the Kerr electro-optic field measurement technique. From measurement results, we propose a physical model for the charge behavior. We have calculated an electric field distribution using finite element method (FEM) based on the charge movement. We compared the results of measurements and calculations and confirmed that the proposed charge behavior model explains well the experimental results in the case of the polarity reversals as well. As a result, a significant validity of the charge behavior model was confirmed. 相似文献
99.
Hiroshi Nagashima Toshifumi Ishikura Mitsuharu Ide 《Korean Journal of Chemical Engineering》1999,16(5):688-693
A spouted bed with an impermeable draft tube was employed to obtain fundamental data of binary mixtures of glass beads for
both the operating conditions and the design factors. These data were compared with those for the coarser particle system
only. From this view point, minimum spouting velocity, pressure drop, hold-up of solid particles within a draft tube, upward
gas flow rate within the annulus and solids circulation rate were determined by changing the total gas flow rate and mass
fraction of finer particles as operating parameters and by changing distance of entrainment zone and draft tube diameter as
geometric parameters. 相似文献
100.
Mika Yoshimura Fujii Katsuhiko Gato Yosuke Ozawa Hiroshi Hisada Tatsuo Koide Motoki Inoue Toshiro Fukami 《European Journal of Lipid Science and Technology》2020,122(3)
In this study, lipid structural change is monitored using Raman spectroscopy during heat treatment, along with the impact of lipid states on the structural and physical properties during the preparation process of the dried and hydrated lipid mixture (LM) similar to intercellular lipid in stratum corneum. The microstructures and thermal behavior of these LMs change depending on the melting of lipid ingredients in the preparation process. It is recognized that variable temperature Raman spectroscopy (VT‐Raman) is a useful and attractive tool for the sensitive in situ monitoring of lipid state changes and lipid melting. The LMs can incorporate D2O into their structures regardless of preparation temperature due to increasing lattice distance by hydration. These results suggest that monitoring lipid structural changes during the heating step is important to precisely prepare target LMs. Practical Applications: This study reveals that VT‐Raman is a useful and attractive tool in in situ monitoring of lipid state change and lipid melting. The monitoring of the preparation process by VT‐Raman is necessary to precisely prepare the target LM similar to intercellular lipid of stratum corneum because the microstructures and thermal properties of these LMs change depending on the melting of lipid ingredients during the preparation process. 相似文献