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991.
A dual-frequency Nd: YAG laser which can output two frequencies with frequency difference of more than 5 gigaherz is developed. By inserting and moving an intracavity quartz crystal wedge in diode pumped Nd:YAG laser, It can be obtained and tuned frequency difference in a wide frequency range. The stabilization of frequency difference in free state is much better than that of birefringent dual-frequency He-Ne lasers at similar laboratory conditions. With such a large tunable frequency difference i.e. short synthetic wavelength, the laser may be used as the light source of absolute distance interferometers. In our experiment, the methods for tuning frequency difference by rotating and applying a tunable force on the intracavity quartz plate are also studied. 相似文献
992.
We have solved a self-consistent problem on interaction of two dipole atoms located at an arbitrary distance from each other
with the field of a quasiresonance light wave, whose intensity is sufficient for the system to manifest nonlinear properties.
The atoms are considered as two-level systems described by means of Bloch optical equations, while the field inside of the
system includes both Coulomb and retarded parts. We consider a situation where atoms are identical and the distance between
them is much smaller than the length of an outer light wave. The distribution of an electric field both inside of a small
object and outside of it is found numerically. It is shown that the amplitude of the electric field in a wave zone depends
substantially on the frequency of the external field and interatomic distance, while the field distribution differs from the
field pattern of an electric dipole. At definite values of the external field intensity an optical multistability is a feature
of the system under investigation. We have elucidated the conditions under which the multistability is manifested in the present
system. The results obtained are considered as the near-field effect in the optics of small objects, which makes it possible
to investigate the structure of small objects by means of optical radiation.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 375–378, May–June, 2000.
The present work was supported by the Russian Foundation for Fundamental Research (grant 98-02-16035) and by a grant from
the Federal Purpose-Oriented Program “Integration.” 相似文献
993.
复合二项过程风险模型的精细大偏差及有限时间破产概率 总被引:1,自引:0,他引:1
讨论基于客户到来的复合二项过程风险模型.在该风险模型中,假设索赔额序列是独立同分布的重尾随机变量序列,不同保单发生实际索赔的概率可以不同,则在索赔额服从ERV的条件下,得到了损失过程的精细大偏差;进一步地,得到了有限时间破产概率的Lundberg极限结果. 相似文献
994.
Tuvi Etzion 《组合设计杂志》2008,16(2):137-151
A doubly constant weight code is a binary code of length n1 + n2, with constant weight w1 + w2, such that the weight of a codeword in the first n1 coordinates is w1. Such codes have applications in obtaining bounds on the sizes of constant weight codes with given minimum distance. Lower and upper bounds on the sizes of such codes are derived. In particular, we show tight connections between optimal codes and some known designs such as Howell designs, Kirkman squares, orthogonal arrays, Steiner systems, and large sets of Steiner systems. These optimal codes are natural generalization of Steiner systems and they are also called doubly Steiner systems. © 2007 Wiley Periodicals, Inc. J Combin Designs 16: 137–151, 2008 相似文献
995.
The inexact Rayleigh quotient iteration (RQI) is used for computing the smallest eigenpair of a large Hermitian matrix. Under
certain condition, the method was proved to converge quadratically in literature. However, it is shown in this paper that
under the original given condition the inexact RQI may not quadratically converge to the desired eigenpair and even may misconverge
to some other undesired eigenpair. A new condition, called the uniform positiveness condition, is given that can fix misconvergence
problem and ensure the quadratic convergence of the inexact RQI. An alternative to the inexact RQI is the Jacobi-Davidson
(JD) method without subspace acceleration. A new proof of its linear convergence is presented and a sharper bound is established
in the paper. All the results are verified and analyzed by numerical experiments.
This work was supported by the National Natural Science Foundation of China (Grant Nos. 10471074, 10771116) and the Doctoral
Program of the Ministry of Education of China (Grant No. 20060003003) 相似文献
996.
XiangLin Yang YangJing Wen Ming Xu 《International Journal of Infrared and Millimeter Waves》2000,21(9):1495-1502
The control scheme of long distance optical transmission is treated based on conception of mode-locked Laser cavity in this paper. The general mode-locking equation of fiber ring soliton Laser is first constructed, then we give the general perturbed nonlinear schrödinger equation, and finally the transmission and control equations of optical soliton communication systems with various different configurations, respectively, are obtained. 相似文献
997.
D. Dymitrov 《Optics & Laser Technology》1986,18(3)
A simple method is described for defining the size and location of the slit in a rainbow holography optical system in order to guarantee the optimal observation conditions of the reconstructed image. A brief explanation of the basic principles of rainbow holography is given and the projection of viewing slits and pseudoscopic, or orthoscopic, images is considered. An application of the method for afocal systems used in rainbow holography is presented. 相似文献
998.
Projected gradient methods for linearly constrained problems 总被引:23,自引:0,他引:23
The aim of this paper is to study the convergence properties of the gradient projection method and to apply these results
to algorithms for linearly constrained problems. The main convergence result is obtained by defining a projected gradient,
and proving that the gradient projection method forces the sequence of projected gradients to zero. A consequence of this
result is that if the gradient projection method converges to a nondegenerate point of a linearly constrained problem, then
the active and binding constraints are identified in a finite number of iterations. As an application of our theory, we develop
quadratic programming algorithms that iteratively explore a subspace defined by the active constraints. These algorithms are
able to drop and add many constraints from the active set, and can either compute an accurate minimizer by a direct method,
or an approximate minimizer by an iterative method of the conjugate gradient type. Thus, these algorithms are attractive for
large scale problems. We show that it is possible to develop a finite terminating quadratic programming algorithm without
non-degeneracy assumptions.
Work supported in part by the Applied Mathematical Sciences subprogram of the Office of Energy Research of the U.S. Department
of Energy under Contract W-31-109-Eng-38.
Work supported in part by the Applied Mathematical Sciences subprogram of the Office of Energy Research of the U.S. Department
of Energy under Contract W-31-109-Eng-38. 相似文献
999.
1000.