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991.
A polynomial-time algorithm for the change-making problem 总被引:1,自引:0,他引:1
David Pearson 《Operations Research Letters》2005,33(3):231-234
Optimally making change—representing a given value with the fewest coins from a set of denominations—is in general NP-hard. In most real money systems however, the greedy algorithm is optimal. We give a polynomial-time algorithm to determine, for a given coin system, whether the greedy algorithm is optimal. 相似文献
992.
Marie-Christine Costa Fethi Jarray Christophe Picouleau 《4OR: A Quarterly Journal of Operations Research》2006,4(1):73-85
This paper studies the days off scheduling problem when the demand for staffing fluctuates from day to another and when the
number of total workdays is fixed in advance for each employee. The scheduling problem is then to allocate rests to employees
with different days off policies: (1) two or three consecutive days off for each employee per week and (2) at least three
consecutive days off for each employee per month. For each one, we propose a polynomial time algorithm to construct a solution
if it exists.
Received: April 2005 / Revised version: October 2005
AMS classification:
60K25, 60K30 相似文献
993.
Componentwise adaptation for high dimensional MCMC 总被引:1,自引:0,他引:1
Summary We introduce a new adaptive MCMC algorithm, based on the traditional single component Metropolis-Hastings algorithm and on
our earlier adaptive Metropolis algorithm (AM). In the new algorithm the adaption is performed component by component. The
chain is no more Markovian, but it remains ergodic. The algorithm is demonstrated to work well in varying test cases up to
1000 dimensions. 相似文献
994.
研究有预算限制的最大多种物资流问题,给出了这个问题的不依赖物资数k的全多项式时间近似算法,其算法复杂性是O~(-ε2m2).同时,利用有预算限制的最大多种物资流问题的研究结果,我们也得到了费用最小的最大多种物资流问题的近似算法和算法复杂性. 相似文献
995.
Nonlinear two-point boundary-value problems (TPBVP) can be reduced to the iterative solution of a sequence of linear problems by means of quasilinearization techniques. Therefore, the efficient solution of linear problems is the key to the efficient solution of nonlinear problems.Among the techniques available for solving linear two-point boundary-value problems, the method of particular solutions (MPS) is particularly attractive in that it employs only one differential system, the original nonhomogeneous system, albeit with different initial conditions. This feature of MPS makes it ideally suitable for implementation on parallel computers in that the following requirements are met: the computational effort is subdivided into separate tasks (particular solutions) assigned to the different processors; the tasks have nearly the same size; there is little intercommunication between the tasks.For the TPBVP, the speedup achievable is ofO(n), wheren is the dimension of the state vector, hence relatively modest for the differential systems of interest in trajectory optimization and guidance. This being the case, we transform the TPBVP into a multi-point boundary-value problem (MPBVP) involvingm time subintervals, withm–1 continuity conditions imposed at the interface of contiguous subintervals. For the MPBVP, the speedup achievable is ofO(mn), hence substantially higher than that achievable for the TPBVP. It reduces toO(m) if the parallelism is implemented only in the time domain and not in the state domain.A drawback of the multi-point approach is that it requires the solution of a large linear algebraic system for the constants of the particular solutions. This drawback can be offset by exploiting the particular nature of the interface conditions: if the vector of constants for the first subinterval is known, the vector of constants for the subsequent subintervals can be obtained with linear transformations. Using decomposition techniques together with the discrete version of MPS, the size of the linear algebraic system for the multi-point case becomes the same as that for the two-point case.Numerical tests on the Intel iPSC/860 computer show that substantial speedup can be achieved via parallel algorithms vis-a-vis sequential algorithms. Therefore, the present technique has considerable interest for real-time trajectory optimization and guidance.Dedicated to the Memory of Professor Jan M. SkowronskiThis paper, based on Refs. 1–3, is a much condensed version of the material contained in these references.The technical assistance of the Research Center on Parallel Computation of Rice University, Houston, Texas is gratefully acknowledged. 相似文献
996.
A passive technique for high-resolution detection of the wavelength of peak reflection from fibre Bragg grating (FBG) sensors is presented. The approach, based on a de-convolution of the FBG spectrum and the spectrometer resolution, essentially overcomes the low spectral resolution (≈0.1 nm) associated with commercial spectrometers employing CCD detection. The performance of two algorithms, the Centroid Detection algorithm (CDA) and the least squares method (LSQ), are compared. The LSQ algorithm offers resolution enhancement of at least two orders of magnitude and is shown to be independent of the FBG intensity and bandwidth over a broad range. 相似文献
997.
Qiqing Yu George Y. C. Wong Menggang Yu 《Annals of the Institute of Statistical Mathematics》2007,59(4):675-695
We consider the estimation problem with classical case-cohort data. The case-cohort design was first proposed by Prentice
(Biometrics 73:1–11, 1986). Most studies focus on the Cox regression model. In this paper, we consider the linear regression
model. We propose an estimator which extends the Buckley–James estimator to the classical case-cohort design. In order to
derive the BJE, there is an additional problem of finding the generalized maximum likelihood estimator (GMLE) of the underlying
distribution functions. We propose a self-consistent algorithm for the GMLE. We also justify that the GMLE is consistent and
asymptotically normally distributed under certain regularity conditions. We further present some simulation results on the
asymptotic properties of the BJE and apply our procedure to a data set used in the literature. 相似文献
998.
999.
S.Koziel和Z.Michalewicz(1999年)提出了一个处理约束的映射,研究该映射与不同算法相结合后的不同的代数结构.从理论上证明了当其与遗传算法相结合时,该映射是同构映射,而在差分演化算法的变异操作下,该映射不是同态映射,更不是同构映射.进而表明,该映射更适宜于与遗传算法相结合,而并不太适宜于与差分演化算法(及其类似的算法)相结合。 相似文献
1000.
Differential evolution algorithms using hybrid mutation 总被引:2,自引:0,他引:2
Differential evolution (DE) has gained a lot of attention from the global optimization research community. It has proved to
be a very robust algorithm for solving non-differentiable and non-convex global optimization problems. In this paper, we propose
some modifications to the original algorithm. Specifically, we use the attraction-repulsion concept of electromagnetism-like
(EM) algorithm to boost the mutation operation of the original differential evolution. We carried out a numerical study using
a set of 50 test problems, many of which are inspired by practical applications. Results presented show the potential of this
new approach. 相似文献