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131.
C.H. Yang W. Xu Z. Zeng C.S. Tang C. Zhang 《Physica E: Low-dimensional Systems and Nanostructures》2006,32(1-2):363
We present a theoretical study on how many-body effects can affect the spin-splitting of a two-dimensional electron gas in the presence of the Rashba spin–orbit interaction. The standard Hartree–Fock approximation and Green's function approach are employed to calculate the energy spectrum and density of states of a spin-split two-dimensional electron gas (2DEG). We find that the presence of the exchange interaction can enhance significantly the spin-splitting of a 2DEG on top of the Rashba effect. The physical reasons behind this important phenomenon are discussed. 相似文献
132.
E. Marsch 《Annalen der Physik》2006,15(6):434-437
The exact eigenfunctions of the spin‐orbit‐coupling operators for a relativistic binary system are calculated. Concerning the eigenvalue problem and the radial part of the wavefunction of the bound state, we provide corrections for our previous calculations [1] that contained some sign errors. 相似文献
133.
134.
In this work we briefly review the present day perspectives for exploiting conventional non-magnetic semiconductor nano-technology to design high speed spin-filter devices. In recent theoretical investigations a high spin polarization has been predicted for the ballistic tunneling current in semiconductor single- and double-barrier asymmetric tunnel structures of III–V semiconductors with strong Rashba spin–orbit coupling. We show in this paper that the polarization in the tunneling can probability be sufficiently increased for producing realistic single-barrier structures by including of the Dresselhaus term into consideration. 相似文献
135.
一致凸Banach空间中渐近非扩张映象的几乎轨道的渐近行为 总被引:1,自引:0,他引:1
设X是有Fréchet可微范数的一致凸Banach空间,C是X的有界闭凸子集,T:C→C是一个渐近非扩张映象.证明了,如果{xn:n≥1}是T的几乎轨道,则序列{x0}弱几乎收敛到集合∩from∞to(n=1)co{xi:i≥n}∩F(T)的唯一点,其中,F(T)是T的不动点集. 相似文献
136.
Walter Schempp 《Acta Appl Math》1997,48(2):185-234
Due to its unequalled advantages, the magnetic resonance imaging (MRI) modality has truly revolutionized the diagnosis and evaluation of pathology. Because many morphological anatomic details that may not be visualized by other high tech imaging methods can now be readily shown by diagnostic MRI, it has already become the standard modality by which all other clinical imaging techniques are measured. The unique quantum physical basis of the MRI modality combined with the imaging capabilities of current computer technology has made this imaging modality a target of interdisciplinary interest for clinicians, physicists, biologists, engineers, and mathematicians. Due to the fact that MRI scanners perform corticomorphic processing, this modality is by far more complex than all the other high tech clinical imaging techniques. The purpose of this paper is to outline a phase coherent wavelet approach to Fourier transform MRI. It is based on distributional harmonic analysis on the Heisenberg nilpotent Lie group G and the associated symplectically invariant symbol calculus of pseudodifferential operators. The contour and contrast resolution of MRI scans which is controlled by symplectic filter bank processing gives the noninvasive MRI modality superiority over X-ray computed tomography (CT) in soft tissue differentiation. 相似文献
137.
This paper describes the operational details of the single-cavity race track microtron of this laboratory. The machine is
capable of providing electrons of 8 MeV energy at 1 mA peak current. Important parameters of the machine and beam handling
system are studied and the results are reported. 相似文献
138.
由于激光技术可使人造卫星轨道测量精度大大提高,因此轨道计算必须考虑广义相对论效应.本文将中间轨道理论推广到考虑广义相对论效应的人造卫星轨道计算中,给出了相对论中间轨道的积分,并导出了以轨道参数为变量的相对论摄动运动方程. 相似文献
139.
K. Farahmand 《Queueing Systems》1996,22(3-4):425-435
We analyze a model queueing system in which customers cannot be in continuous contact with the server, but must call in to request service. If the server is free, the customer enters service immediately, but if the server is occupied, the unsatisfied customer must break contact and reapply for service later. There are two types of customer present who may reapply. First transit customers who arrive from outside according to a Poisson process and if they find the server busy they join a source of unsatisfied customers, called the orbit, who according to an exponential distribution reapply for service till they find the server free and leave the system on completion of service. Secondly there are a number of recurrent customers present who reapply for service according to a different exponential distribution and immediately go back in to the orbit after each completion of service. We assume a general service time distribution and calculate several characterstic quantities of the system for both the constant rate of reapplying for service and for the case when customers are discouraged and reduce their rate of demand as more customers join the orbit. 相似文献
140.
Lia Petracovici 《Transactions of the American Mathematical Society》2005,357(9):3481-3491
Let , , and let denote the sequence of convergents to the regular continued fraction of . Let be a function holomorphic at the origin, with a power series of the form . We assume that for infinitely many we simultaneously have (i) , (ii) the coefficients stay outside two small disks, and (iii) the series is lacunary, with for . We then prove that has infinitely many periodic orbits in every neighborhood of the origin.