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131.
Michel Planat 《电信纪事》1996,51(7-8):391-406
The synchronization of oscillators is defined step by step from the exemple of an electronic phase-locked loop. Besides, an injection-locked pulsed delay oscillator is built in which the signal is synchronized both in its frequency and its duration : the local behaviour (the carrier) is thus resonating with the global behaviour (the envelope). A model of the electronic wave function in terms of the fundamental groups of punctured Riemann surfaces is attempted. The structure of synchronization zones goes in favour of that hypothesis. 相似文献
132.
Many rate constants of elementary steps on single crystals have been measured. Their pre-exponential factors can now be compared to those calculated by transition state theory. Such a calculation is presented in this Letter with due attention to microscopic reversibility, standard states, and configurational entropy. 相似文献
133.
134.
Donglin Wang Michel Fattouche Fadhel Ghannouchi 《Circuits, Systems, and Signal Processing》2012,31(3):1215-1227
In this paper, orthogonal frequency division multiplexing (OFDM) for time-based range estimation (TBRE) in a separable multipath
channel is investigated and analyzed with respect to its accuracy. First, the Cramer–Rao lower bound (CRLB) in a separable
multipath channel is theoretically derived, and indicates a similar expression to that for a single path channel. The CRLB
for non-data-bearing (NDB) OFDM transmission is compared to that for pseudo-noise (PN) transmission, demonstrating a large
performance gap in favor of the NDB OFDM. Furthermore, the maximum likelihood estimator (MLE) for TBRE in a separable multipath
channel is theoretically derived, also demonstrating a similar expression to that in a single path channel, except that several
peaks instead of one peak are expected in a separable multipath channel corresponding to all arrival paths. The MLE for TBRE
is then compared to the commonly used MLE for channel estimation, showing an equal performance in terms of mean square error
when using an NDB OFDM transmission. Simulation results demonstrate a good agreement with our proposed theory. 相似文献
135.
Carlos Colman-Meixner Ferhat Dikbiyik M. Farhan Habib Massimo Tornatore Chen-Nee Chuah Biswanath Mukherjee 《Photonic Network Communications》2014,27(3):141-153
Cloud-computing services are provided to consumers through a network of servers and network equipment. Cloud-network (CN) providers virtualize resources [e.g., virtual machine (VM) and virtual network (VN)] for efficient and secure resource allocation. Disasters are one of the worst threats for CNs as they can cause massive disruptions and CN disconnection. A disaster may also induce post-disaster correlated, cascading failures which can disconnect more CNs. Survivable virtual-network embedding (SVNE) approaches have been studied to protect VNs against single physical-link/-node and dual physical-link failures in communication infrastructure, but massive disruptions due to a disaster and their consequences can make SVNE approaches insufficient to guarantee cloud-computing survivability. In this work, we study the problem of survivable CN mapping from disaster. We consider risk assessment, VM backup location, and post-disaster survivability to reduce the risk of failure and probability of CN disconnection and the penalty paid by operators due to loss of capacity. We formulate the proposed approach as an integer linear program and study two scenarios: a natural disaster, e.g., earthquake and a human-made disaster, e.g., weapons-of-mass-destruction attack. Our illustrative examples show that our approach reduces the risk of CN disconnection and penalty up to 90 % compared with a baseline CN mapping approach and increases the CN survivability up to 100 % in both scenarios. 相似文献
136.
Ilia?Polianpolian@informatik.uni-freiburg.de" title="ilia@polian.de polian@informatik.uni-freiburg.de" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author Piet?Engelke Michel?Renovell Bernd?Becker 《Journal of Electronic Testing》2005,21(1):57-69
We study the behavior of feedback bridging faults with non-zero bridge resistance in both combinational and sequential circuits. We demonstrate that a test vector may detect the fault, not detect the fault or lead to oscillation, depending on bridge resistance. Moreover, the resistance intervals in which a particular behavior is observed are not necessarily contiguous. We demonstrate non-trivial behavior for situations in which a detection seems impossible, namely disabled loops going through a gate with controlling values on its side inputs.We outline the multiple strengths problem which arises due to the fact that a critical bridge resistance depends on the strengths of the signals driving the bridge, which in turn are functions of the number of the on-transistors, these again depending on the bridge resistance, making such a fault very hard to resolve. For sequential circuits, we describe additional difficulties caused by the need to account for implications on bridge behavior, which have originated in the previous time frames. We conclude that the complexity of resistive feedback bridging fault simulation accurate enough to resolve such situations will probably be prohibitively high and propose possible simplifying assumptions. We present simulation results for ISCAS benchmarks using these assumptions with and without taking oscillation into account.This revised version was published online in March 2005 with corrections to the cover date. 相似文献
137.
Yandi Luo Guojie Chen Shuo Chen Nafees Ahmad Muhammad Azam Zhuanghao Zheng Zhenghua Su Michel Cathelinaud Hongli Ma Zhigang Chen Ping Fan Xianghua Zhang Guangxing Liang 《Advanced functional materials》2023,33(14):2213941
Exhibiting outstanding optoelectronic properties, antimony selenide (Sb2Se3) has attracted considerable interest and has been developed as a light absorber layer for thin-film solar cells over the decade. However, current state-of-the-art Sb2Se3 devices suffer from unsatisfactory “cliff-like” band alignment and severe interface recombination loss, which deteriorates device performance. In this study, the heterojunction interface of an Sb2Se3 solar cell is improved by introducing effective aluminum (Al3+) cation into the CdS buffer layer. Then, the energy band alignment of Sb2Se3/CdS:Al heterojunction is modified from a “cliff-like” structure to a “spike-like” structure. Finally, heterojunction interface engineering suppresses recombination losses and strengthens carrier transport, resulting in a high efficiency of 8.41% for the substrate-structured Sb2Se3 solar cell. This study proposes a facile strategy for interfacial treatment and elucidates the related carrier transport enhancement mechanism, paving a bright avenue to overcome the efficiency bottleneck of Sb2Se3 thin-film solar cells. 相似文献
138.
With the advent of non-hierarchical routing in circuit-switched telecommunication networks, on-line routing policies have been developed with the objective of optimizing some measure of gain or performance. These policies are decentralized. However, traditional planning models are centralized models. We present a decentralized routing model to be used in network planning. We compare it theoretically and empirically with a centralized multicommodity flow model previously presented. The two models are solved by the same type of algorithm, a convex simplex implementation, adapted differently according to the model. Comparative results between planning models reproducing the two policies are discussed. 相似文献
139.
Annals of Telecommunications - Le partage du risque est une des raisons les plus souvent avancées pour expliquer les clauses financières des contrats de licence. Pour autant, aucune... 相似文献
140.
Michel C. James 《International Journal of Satellite Communications and Networking》1995,13(3):171-176
Recently many companies and consortia have considered launching LEO satellites for such projects as remote sensing, transportation and mining operations. When the multiple low Earth orbit (LEO) satellites are transmitting they can interfere with existing terrestrial microwave and satellite earth-stations in the fixed and mobile service. The interference problem is related to the number of proposed LEOs and the altitude and consequently the time to orbit the earth. These systems usually consist of many small satellites, and each satellite stays in the beam of a terrestrial station for up to 72 seconds in each 222 minute orbit. Earth coverage could be obtained by 48 (LEO) satellites 1500 km above the earth in polar orbit, and hence at least one LEO would always be interfering with terrestrial networks. A technical evaluation would then be required to determine the resultant BER (bit error rate) effecting existing terrestrial services. A determination can then be made to support such a LEO system or object via official channels such as the ITU. 相似文献