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1.
G. P. Westphal 《Journal of Radioanalytical and Nuclear Chemistry》1994,179(1):55-59
By adapting noise filtering to individual pulse intervals, the Preloaded Filter (PLF) pulse processor (1) combines high resolution with optimum throughput efficiency. As a consequence, its output pulse interval distribution contains strong non-random components which render conventional ADC dead-time correction an impossibility. Quantitative correction of dead-time and pileup losses of the PLF processor may be achieved, however, with the Virtual Pulse Generator (2), together with a new, distribution-independent method of measuring ADC losses which is based on a pulse counting technique. 相似文献
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Barrier coverage of a wireless sensor network is a critical issue in military and homeland security applications, aiming to detect intruders that attempt to cross the deployed region. While a range of problems related to barrier coverage have been investigated, little effort has been made to explore the effects of different sensor deployment strategies and mechanisms to improve barrier coverage of a wireless sensor network after it is deployed. In this paper we study the barrier coverage of a line-based sensor deployment strategy and explore how to exploit sensor mobility to improve barrier coverage. We first establish a tight lower bound for the existence of barrier coverage under the line-based deployment. Our results show that the barrier coverage of the line-based deployment significantly outperforms that of the Poisson model when the random offsets are relatively small compared to the sensor’s sensing range. To take advantage of the performance of line-based deployment, we further devise an efficient algorithm to relocate mobile sensors based on the deployed line so as to improve barrier coverage. The algorithm finds barrier gaps and then relocates mobile sensors to fill the gaps while at the same time balancing the energy consumption among mobile sensors. Simulation results show that the algorithms can effectively improve the barrier coverage of a wireless sensor network for a wide range of deployment parameters. Therefore, in wireless sensor network applications, the coverage goal, possible sensor deployment strategies, and sensor mobility must be carefully and jointly considered. The results obtained in this paper will provide important guidelines and insights into the deployment and performance of wireless sensor networks for barrier coverage. 相似文献
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Mohand O. Saed Cedric P. Ambulo Hyun Kim Rohit De Vyom Raval Kyle Searles Danyal A. Siddiqui John Michael O. Cue Mihaela C. Stefan M. Ravi Shankar Taylor H. Ware 《Advanced functional materials》2019,29(3)
Three‐dimensional structures that undergo reversible shape changes in response to mild stimuli enable a wide range of smart devices, such as soft robots or implantable medical devices. Herein, a dual thiol‐ene reaction scheme is used to synthesize a class of liquid crystal (LC) elastomers that can be 3D printed into complex shapes and subsequently undergo controlled shape change. Through controlling the phase transition temperature of polymerizable LC inks, morphing 3D structures with tunable actuation temperature (28 ± 2 to 105 ± 1 °C) are fabricated. Finally, multiple LC inks are 3D printed into single structures to allow for the production of untethered, thermo‐responsive structures that sequentially and reversibly undergo multiple shape changes. 相似文献
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One of the much-debated novel features of theories with extra dimensions is the presence of power-like loop corrections to gauge coupling unification, which have the potential of allowing a significant reduction of the unification scale. A recognized problem of such scenarios is the UV sensitivity of the above power corrections. We consider situations where the grand unified group is broken by the vacuum expectation value of a bulk field and find that, because of the softness of this extra-dimensional symmetry-breaking mechanism, power-like threshold corrections are calculable and generic in many of the most relevant settings. While the precision is limited by the presence of higher-dimension bulk operators, the most dangerous of these operators are naturally forbidden by symmetries of the bulk theory. Particularly interesting and constrained scenarios arise in the context of higher-dimensional supersymmetry. Our phenomenological exploration of SU(5) models in 5d, linked in particular with more recently discussed orbifold GUT models, shows promising results. 相似文献
8.
Femtosecond laser direct writing is employed for the fabrication of buried tubular waveguides in bulk poly(methyl methacrylate). A novel technique using selective chemical etching is presented to resolve the two-dimensional refractive-index profile of the fabrication structures. End-to-end coupling in the waveguides reveals a near-field intensity distribution that results from the superimposition of several propagating modes with different azimuthal symmetries. Mode analysis of the tubular waveguides is performed using the finite-difference method, and the possible propagating mode profiles are compared with the experimental data. 相似文献
9.
V. V. Nesvizhevsky A. K. Petukhov H. G. Börner T. A. Baranova A. M. Gagarski G. A. Petrov K. V. Protasov A. Yu Voronin S. Baeßler H. Abele A. Westphal L. Lucovac 《The European Physical Journal C - Particles and Fields》2005,40(4):479-491
We have studied neutron quantum states in the potential well formed by the earths gravitational field and a horizontal mirror. The estimated characteristic sizes of the neutron wave functions in the two lowest quantum states correspond to expectations with an experimental accuracy. A position-sensitive neutron detector with an extra-high spatial resolution of
m was developed and tested for this particular experiment, to be used to measure the spatial density distribution in a standing neutron wave above a mirror for a set of some of the lowest quantum states. The present experiment can be used to set an upper limit for an additional short-range fundamental force. We studied methodological uncertainties as well as the feasibility of improving further the accuracy of this experiment.Received: 31 July 2004, Published online: 7 March 2005PACS:
03.65, 28.20
Correspondence to: V. Nesvizhevsky 相似文献
10.
Cordula Grüttner Knut Müller Joachim Teller Fritz Westphal Allan Foreman Robert Ivkov 《Journal of magnetism and magnetic materials》2007
Bionized nanoferrite (BNF) particles with high specific power absorption rates were synthesized in the size range of 20–100 nm by high-pressure homogenization for targeted cancer therapy with alternating magnetic fields. Several strategies were used to conjugate antibodies to the BNF particles. These strategies were compared using an immunoassay to find optimal conditions to reach a high immunoreactivity of the final antibody–particle conjugate. 相似文献