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991.
Jun Yun Kim Takuma Yasuda Yu Seok Yang Chihaya Adachi 《Advanced materials (Deerfield Beach, Fla.)》2013,25(19):2666-2671
992.
Yoh Yasuda Shigeru Yokoyama Masayuki Minowa Tomoyuki Satoh 《IEEJ Transactions on Electrical and Electronic Engineering》2012,7(6):559-566
Lightning damage to wind turbine blades is of great concern to wind power installations. We investigate various issues arising from lightning damage and assess the causes through actual lightning observations as well as from high‐voltage and large‐current experiments. Although installing lightning receptors and down conductors provide a good countermeasure, blade damage can still be caused by lightning still. New techniques are needed to better protect blades from lightning surges; these may include not only better performance and layout of receptors, but also independent lightning towers and new types of blade materials. This paper provides a classification of blade damage sustained in winter lightning, ranked in severity by analyzing the many incidents of damage that have actually occurred in Japan. Moreover, a list of possible causes of damage and relative countermeasures is also presented. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
993.
Kazunori Kurihara Yutaka Sasaki Yoshifumi Zoka Naoto Yorino 《Electrical Engineering in Japan》2013,184(2):36-43
The power market will be in a highly competitive environment because of power deregulation. The electric power companies have raised business efficiency to reduce the number of employees and centralize business establishments. Furthermore, the installation of photovoltaic generation will increase because of energy policy. However, the electric power companies must maintain power supply reliability. Therefore, to reinforce reliability in distribution systems is a significant problem. In this paper, we propose the optimal placement of distribution section switches to maintain power supply reliability in such a situation, and we present simulation results obtained for the original distribution system using a genetic algorithm. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(2): 36–43, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22375 相似文献
994.
Naoto Yorino Yutaka Sasaki Shoki Fujita Yoshifumi Zoka Yoshiharu Okumoto 《Electrical Engineering in Japan》2013,182(1):30-38
A large amount of PV penetration may introduce uncertainties in future power system planning and operations. This paper proposes the concept of “Robust Security (RS)” and the “RS region” in order to investigate power system security in the presence of a large amount of uncertainties. The RS region is defined as the region of power system operation where the system is secure under uncertainties. It is shown that the region tends to shrink and disappear for a high degree of PV penetration. Emerging problems concerned with security in future power systems are investigated. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(1): 30–38, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22289 相似文献
995.
Akira Suga Mayuko Yasuda Yasuto Fujimaki Minoru Takekawa Shoji Fujisawa 《Polycyclic Aromatic Compounds》2013,33(3-4):289-293
We have synthesized undecacyclic aromatic hydrocarbons using condensation of dibenzoanthrones. For example, dibenzo[ a,o ]dinaphtho[3,2,1- cd ;1,2,3- lm ]perylene, diphenanthra[1,2,3- cd ; 3,2,1- lm ]perylene and diphenanthra[2,3,4- cd ;4,3,2- lm ]perylene were produced from 5,6-, 8,9- and 10,11-dibenzoanthrones, respectively. In the present study, we have extended our work and aimed to synthesize new undecacyclic aromatic hydrocarbons by the use of 9,10-dibenzoanthrone (7 H -benzo[ de ]naphthacene-7-one) as a starting material. 9,10-Dibenzoanthrone was prepared by the cyclization of 1,2'-dinaphthylketone in aluminum chloride anhydride and sodium chloride, and the structure was confirmed by NMR measurements. It dissolves into ethanol and crystallizes in pale yellow needles; its melting point is 198.2-199.3°. The condensation of 9,10-dibenzoanthrone should give undecacyclic aromatic hydrocarbons such as benzo[ vwx ]naphtha[12,1,2- cde ] hexaphene. 相似文献
996.
Multi-hop packet transmission error due to packet collision is a serious issue for realizing large-scale wireless ad hoc networks. In order to solve the issues, a multicode-reception spread-spectrum (MCR-SS)-CSMA/CA scheme is proposed as multiple access scheme for layered-tree networks. This scheme is further improved by adding a time group access (TGA) technique to gain higher interference reduction between nodes. The proposed TGA scheme divides the layered-tree network into upper subnets group and lower subnets group, thus reducing collision probability among subnets. Network throughput and data delivery ratio for the proposed scheme are analyzed by simulations based on the IEEE 802.15.4/ZigBee specification. Simulation results show that the proposed schemes can improve packet delivery ratio and network throughput remarkably. 相似文献
997.
Yueping Cai Motoharu Matsuura Eiji Oki Naoto Kishi Tetsuya Miki 《Photonic Network Communications》2010,20(3):293-302
This article presents a resilient star-ring optical broadcast-and-select network with a centralized multi-carrier light source
(C-MCLS). It consists of a star part network and a ring part network. Optical carriers generated by the C-MCLS are broadcast
to all network nodes, which select and utilize them for data transmission. Optical carrier distribution as well as data transmission
and receiving are performed in the star part network. The ring part network is for fiber failure recovery. The network resilience
property enables the design of a fast distributed failure recovery scheme to deal with single and multiple fiber failures.
We introduce a fiber connection automatic protection switching (FC-APS) architecture that only consists of optical couplers
and 1 × 2 optical switches for each network node. Based on the FC-APS architecture, we design a distributed failure recovery
scheme to recover the carriers and data affected by fiber failures. The fiber failure detection and failure recovery operations
are performed by each network node independently only using its local information. We evaluate the recovery time of the distributed
failure recovery scheme compared with that of the centralized one. Numerical results show that the distributed scheme greatly
reduces the recovery time compared to the centralized configuration in the recoveries of both single and multiple fiber failures.
Optical power loss analysis and compensation of the recovery routes in the distributed scheme are also presented. We show
the required number of optical amplifiers for the longest recovery route in the distributed scheme under different numbers
of network nodes and fiber span lengths. 相似文献
998.
Tatsuki Hiraoka Ali Izadi‐Najafabadi Takeo Yamada Don N. Futaba Satoshi Yasuda Osamu Tanaike Hiroaki Hatori Motoo Yumura Sumio Iijima Kenji Hata 《Advanced functional materials》2010,20(3):422-428
An approach is presented to make a “surface‐only solid” with a surface area of 2 240 m2 g?1 (1 310 m2 cm?3), corresponding to 85% of the atoms constituting a surface, by opening single‐walled carbon nanotube forests and solids via controlled oxidation. The controllability of the approach is demonstrated by tailoring the hole size to match the guest molecule, for example, nitrogen, fullerene, or solvated ions. These features make the surface‐only solid an ideal vessel for material and energy storage, as demonstrated by its use for electrodes to realize a light and compact supercapacitor with high energy (24.7 W h kg?1) and power (98.9 kW kg?1) densities, exceeding those of activated carbon (16.9 W h kg?1 and 35.7 kW kg?1). 相似文献
999.
K. Yasuda M. NomachiY. Sugaya H. YamamotoH. Komatsu 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(20):2180-2183
Modifications of an in-air microbeam system at the Wakasa Wan Energy Research Center designed to improve its performance are described. In the previous setup, a silicon nitride membrane (area: 1 × 1 mm2; thickness: 100 nm) was used for the beam exit window and the distance between the window and the sample was restricted to ?1.7 mm. Due to this restriction, the beam spot size obtained using the previous setup was 13 × 13 μm2. To reduce the beam spot size, the beam exit window was replaced by a silicon nitride membrane (area: 3 (horizontal) × 2 (vertical) mm2; thickness: 200 nm). In this setup, the sample can be moved as close as 0.7 mm to the window, enabling a beam spot size of 7 × 6 μm2 to be achieved. An additional Si-PIN X-ray detector was installed to estimate the relative number of beam particles. It detects X-rays from the beam exit window. The number of the X-rays from the beam exit window (which is proportional to the number of beam particles) is used for quantitative analysis and for online monitoring of the beam current. This system has the potential to be used for simultaneous particle-induced X-ray emission (PIXE) and particle-induced gamma-ray emission (PIGE) measurements and for studying dental medicine. 相似文献
1000.
The impact of the introduction of ICRP Publication 103 on neutron dosimetry was analysed by calculating effective doses in various operational neutron fields, using dose conversion coefficients derived from the recommendations given in ICRP 103 and ICRP 60. It was found from the analysis that effective doses based on ICRP 103 are generally smaller than those based on ICRP 60, mainly owing to the revision of w(R) assigned to neutrons. The results also indicate that H*(10) can provide a conservative estimate for ICRP 103-based effective doses in most neutron fields. These tendencies suggest that the radiological protection system currently adopted in accelerators and nuclear facilities can be maintained after the introduction of ICRP 103, with respect to neutron dosimetry. 相似文献