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991.
992.
Xuan Chen Xuemei Ge Yun Qian Haozheng Tang Jialin Song Xinhua Qu Bing Yue Wei‐En Yuan 《Advanced functional materials》2020,30(38)
Peripheral nerve injury is a common clinical problem bringing heavy burden to patients, due to its high incidence and unsatisfactory treatment. Nerve guidance conduit (NGC) is a promising scaffold for peripheral nerve repair, and bioactive agents are applied for great functional recovery. Melatonin (MLT) and Fe3O4 magnetic nanoparticles (Fe3O4‐MNPs) are proven to inhibit oxidative stress, inflammation, and induce nerve regeneration. Herein, a multilayered composite NGC loaded with MLT and Fe3O4‐MNPs is designed for sequential and sustainable drug release, creating an appropriate microenvironment for nerve regeneration. The composite scaffold shows sufficient mechanical strength and biocompatibility in vitro, and evidently promotes morphological, functional, and electrophysiological recovery of regenerated sciatic nerves in vivo. This work proves that the multilayered conduits show great prospect in the long‐term nerve defects treatment due to easy manufacture and desired efficacy. 相似文献
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996.
Kai Caihong Yu Nenghai Chen Yuzhong 《电子科学学刊(英文版)》2007,24(1):1-9
Transmission Control Protocol (TCP) optimization in Mobile Ad hoc NETworks (MANETs) is a challenging issue because of some unique characteristics of MANETs. In this paper, a new end-to-end mechanism based on multiple metrics measurement is proposed to improve TCP performance in MANETs. Multi-metric Measurement based Enhancement of TCP (MME-TCP) designs the metrics and the identification algorithm according to the characteristics of MANETs and the experiment results. Furthermore, these metrics are measured at the sender node to reduce the overhead of control information over networks. Simulation results show that MME-TCP mechanism achieves a significant performance improvement over standard TCP in MANETs. 相似文献
997.
Wang Pengjun Yu Junjun 《电子科学学刊(英文版)》2007,24(2):225-231
First the research is conducted on the design of the two-phase sinusoidal power clock generator in this paper. Then the design of the new adiabatic logic circuit adopting the two-phase sinusoidal power clocks--Clocked Transmission Gate Adiabatic Logic (CTGAL) circuit is presented. This circuit makes use of the clocked transmission gates to sample the input signals, then the output loads are charged and discharged in a fully adiabatic manner by using bootstrapped N-Channel Metal Oxide Semiconductor (NMOS) and Complementary Metal Oxide Semiconductor (CMOS) latch structure. Finally, with the parameters of Taiwan Semiconductor Manufacturing Company (TSMC) 0.25um CMOS device, the transient energy consumption of CTGAL, Bootstrap Charge-Recovery Logic (BCRL) and Pass-transistor Adiabatic Logic (PAL) including their clock generators is simulated. The simulation result indicates that CTGAL circuit has the characteristic of remarkably low energy consumption. 相似文献
998.
Samples of composites of graphene with indium or indium-gallium alloy as the matrix were prepared by a process of spreading
exfoliated graphene oxide on the foils, repeatedly folding and rolling. The foils were intermittently annealed and the process
repeated by addition of more graphene oxide. Indium flux was used to remove any indium or gallium oxide. The samples were
characterized by x-ray diffraction, and optical and scanning electron microscopy (SEM). Electrical resistivity and temperature
coefficient of resistance (TCR) were measured using a four-probe method in the temperature range of 260 K to 340 K, and the
results were used to determine the volume fraction of graphene from effective mean-field analysis. The volume fraction of
graphene remained between 0.11 and 0.14 in samples of In with graphene and between 0.12 and 0.13 in samples of In-Ga with
graphene. The results indicate that the electrical resistivity and the TCR of the composite were reduced by the addition of
graphene. The resistivity of graphene remained between 1.19 × 10−6 ohm cm and 1.87 × 10−6 ohm cm in all samples and was thus almost independent of the matrix composition. The electrical resistivity of graphene was
found to be an order of magnitude smaller than that of indium or the indium-gallium alloy. 相似文献
999.
Next-generation wireless networks should be able to coordinate and integrate different communication systems. It has been a challenging problem to support a seamless handover in these diverse wireless network environments. Link level triggers can provide information about events which can help handover decision and layer 3 entities better streamline their handover related activities. In most conventional layer 2 triggering approaches, a pre-defined threshold for a specific perspective such as the received signal strength is used. This may cause too late or too early handover executions. In this paper we propose a new predictive handover framework that uses the neighbor network information to generate timely the link triggers so that the required handover procedures can appropriately finish before the current link goes down. First we estimate a required handover time for the given neighbor network conditions, then using a predictive link triggering mechanism the handover start time is dynamically determined to minimize handover costs. The handover costs are analyzed in terms of the total required handover time and the service disruption time. The numerical analysis and simulation results show that the proposed method significantly enhances the handover performance in heterogeneous wireless networks. 相似文献
1000.
A distributed node localization scheme for wireless sensor networks (WSNs) is presented in this paper, and it includes three generic phases: (1) determine node-beacon distances, (2) compute node positions, and (3) refine the positions. Different from previous researches, we propose an algorithm combination Min–max + LI for the position derivation and SD method for the refinement in our scheme. Simulation shows that our proposed scheme can perform more robust than some representative distributed node localization schemes presented in previous researches in terms of the trade-off among accuracy, coverage, computation cost, and communication overhead. 相似文献