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991.
基于相对熵的不完全信息群体专家权重的集结 总被引:2,自引:1,他引:1
万树平 《应用数学与计算数学学报》2009,23(1):66-70
针对属性权重信息和属性效用信息都不完全的群体多属性决策问题,运用相对熵理论提出了一种专家权重的确定方法.该方法通过集结各方案的综合评价值向量,客观地得到专家的权重,避免系统聚类方法中由给定相似度水平归类而产生的主观性问题.应用实例表明了方法的有效性和实用性. 相似文献
992.
该文利用欧拉算子得出了多正则函数边值问题的解, 同时给出了欧拉算子的一些应用. 相似文献
993.
二阶奇异微分方程组边值问题两个正解的存在性 总被引:1,自引:0,他引:1
利用锥拉伸和锥压缩不动点定理,给出了一类二阶微分方程组奇异边值问题两个正解的存在性. 相似文献
994.
非线性奇异三阶微分方程周期边值问题的正解 总被引:2,自引:0,他引:2
讨论非线性奇异三阶微分方程的周期边值问题{u″+ρ^3u=f(t,u),t∈I=(0,2π),ρ∈(0,1/√3)是常数 u^(i)(0)=u^(t)(2π),i=0,1,2
的正解存在性问题.通过与一个线性算子相关的第一特征值的讨论,运用不动点指数定理,得到了正解存在的结果. 相似文献
995.
We study both theoretically and numerically the Lyapunov families which bifurcate in the vertical direction from a horizontal
relative equilibrium in ℝ3. As explained in [1], very symmetric relative equilibria thus give rise to some recently studied classes of periodic solutions.
We discuss the possibility of continuing these families globally as action minimizers in a rotating frame where they become
periodic solutions with particular symmetries. A first step is to give estimates on intervals of the frame rotation frequency
over which the relative equilibrium is the sole absolute action minimizer: this is done by generalizing to an arbitrary relative
equilibrium the method used in [2] by V. Batutello and S. Terracini.
In the second part, we focus on the relative equilibrium of the equal-mass regular N-gon. The proof of the local existence of the vertical Lyapunov families relies on the fact that the restriction to the corresponding
directions of the quadratic part of the energy is positive definite. We compute the symmetry groups G
r/s
(N, k, η) of the vertical Lyapunov families observed in appropriate rotating frames, and use them for continuing the families globally.
The paradigmatic examples are the “Eight” families for an odd number of bodies and the “Hip- Hop” families for an even number.
The first ones generalize Marchal’s P
12 family for 3 bodies, which starts with the equilateral triangle and ends with the Eight [1, 3–6]; the second ones generalize
the Hip-Hop family for 4 bodies, which starts from the square and ends with the Hip-Hop [1, 7, 8].
We argue that it is precisely for these two families that global minimization may be used. In the other cases, obstructions
to the method come from isomorphisms between the symmetries of different families; this is the case for the so-called “chain”
choreographies (see [6]), where only a local minimization property is true (except for N = 3). Another interesting feature of these chains is the deciding role played by the parity, in particular through the value
of the angular momentum. For the Lyapunov families bifurcating from the regular N-gon whith N ≤ 6 we check in an appendix that locally the torsion is not zero, which justifies taking the rotation of the frame as a parameter.
To the memory of J. Moser, with admiration 相似文献
996.
Patrick Meyer 《4OR: A Quarterly Journal of Operations Research》2009,7(2):191-194
This is a summary of the author’s Ph.D. thesis, defended on 8 October 2007 at the University of Luxembourg and the Faculté
Polytechnique de Mons, under the joint supervision of Raymond Bisdorff and Marc Pirlot. The thesis is written in English and
is available from the author upon request. The work is situated in the field of multiple criteria decision analysis. It mostly
deals with what we call progressive methods, i.e., iterative procedures presenting partial conclusions to the decision maker that can be refined at further steps of
the analysis. Such progressive methods have been studied in the context of multiattribute value theory and outranking methods.
相似文献
997.
998.
Membrane transport proteins are essential for cellular uptake of numerous salts, nutrients and drugs. Bilitranslocase is a transporter, specific for water-soluble organic anions, and is the only known carrier of nucleotides and nucleotide-like compounds. Experimental data of bilitranslocase ligand specificity for 120 compounds were used to construct classification models using counter-propagation artificial neural networks (CP-ANNs) and support vector machines (SVMs). A subset of active compounds with experimentally determined transport rates was used to build predictive QSAR models for estimation of transport rates of unknown compounds. Several modelling methods and techniques were applied, i.e. CP-ANN, genetic algorithm, self-organizing mapping and multiple linear regression method. The best predictions were achieved using CP-ANN coupled with a genetic algorithm, with the external validation parameter QV2 of 0.96. The applicability domains of the models were defined to determine the chemical space in which reliable predictions can be obtained. The models were applied for the estimation of bilitranslocase transport activity for two sets of pharmaceutically interesting compounds, antioxidants and antiprions. We found that the relative planarity and a high potential for hydrogen bond formation are the common structural features of anticipated substrates of bilitranslocase. These features may serve as guidelines in the design of new pharmaceuticals transported by bilitranslocase. 相似文献
999.
1000.