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61.
新的大尺寸截面配对式视觉测量方法的研究 总被引:1,自引:0,他引:1
根据大尺寸测量系统的现状,从分析线结构光入手,提出了组建传感器对测量方法,使每对传感器具备差动测量能力,提高单点测量精度;利用坐标测量臂和激光跟踪仪的大尺寸测量能力,对传感器坐标系进行全局校准,提高校准的精度和效率;研究椭圆检测算法,提出利用椭圆平行弦中点连线必过椭圆中心基本定理,求出椭圆中心坐标,拟合出椭圆形状;通过理论分析,该方法切实可行。 相似文献
62.
Control systems designed by the principle of matching gives rise to problems of evaluating the peak output. This paper proposes a practical method for computing the peak output of linear time-invariant and non-anticipative systems for a class of possible sets that are characterized with many bounding conditions on the two- and/or the infinity-norms of the inputs and their derivatives. The original infinite-dimensional convex optimization problem is approximated as a large-scale convex programme defined in a Euclidean space, which are associated with sparse matrices and thus can be solved efficiently in practice. The numerical results show that the method performs satisfactorily, and that using a possible set with many bounding conditions can help to reduce the design conservatism and thereby yield a better match. 相似文献
63.
利用Lyapunov函数方法、系统分解法以及矩阵不等式等方法研究一类具有脉冲行为的广义互联大系统的渐近稳定性及分散镇定问题,在子系统正则且零解渐近稳定的条件下,给出广义线性互联大系统的渐近稳定莉定的一个充分条件,并设计适当的反馈律,以实现广义互联大系统的镇定。通过仿真实例说明主要结果。 相似文献
64.
According to the classic harmonic approach, an orientation density function (odf)f is expanded into its corresponding Fourier orthogonal series with respect to generalized spherical harmonics, and a pole density function (pdf)
into its corresponding Fourier orthogonal series with respect to spherical harmonics. While pdfs are even (antipodally symmetric) functions, odfs are generally not. Therefore, the part
of the odf which cannot be determined from normal diffraction pdfs can be mathematically represented as the odd portion of its series expansion. If the odff is given, the even part
can be mathematically represented explicitly in terms off itself. Thus, it is possible to render maps ofharmonic orientation ghosts, and to evaluatevariants of mathematical standard odfs resulting in identical pdfs independent of pdf data. However, if only normal diffraction pdfs are known, the data-dependentvariation width of feasible odfs remained unaccessible, and within the harmonic approach a measure of confidence in a solution of the pdf-to-odf inversion problem does not exist.According to any discrete approach, an odff defined on some setG of orientations is expanded into its corresponding Fourier orthogonal series with respect to indicator functions of the elements of a partition ofG, and a pdf
defined on the upper (lower) unit hemisphereS
+
3
3 into its corresponding Fourier orthogonal series with respect to indicator functions of the elements of a partition ofS
+
3
. The ambiguity of the pdf-to-odf inversion problem is discussed in terms of column-rank deficiency of the augmented projection matrix. The implication of the harmonic approach to split an odf into auniquely determined and anundetermined part does no longer seem to be reasonable. However, it is possible to numerically determine data-dependent confidence intervals for the Fourier coefficients with respect to the indicator functions which can be immediately interpreted as mean orientation densities within the elements of the partition ofG. Doing so for all Fourier coefficients in the finite series expansion, i.e. for all elements of the partition of the setG, eventually results in the data-dependent variation width of odfs feasible with respect to given pdf data, and to the partitions ofG andS
+
3
.Thus it is confirmed that the appearance of orientation ghosts, in particular correlations oftrue andghost orientation components, depends on the representation of an odf. It may be questioned whether in practical applications the implicit assumption of the harmonic method that the even part
can be determined uniquely and free of error is generally a reasonable initial condition to develop ghost correction procedures. 相似文献
65.
Danyang Zhao Xiaoying Wang Wenming Zhang Yijing Zhang Yu Lei Xintang Huang Qiancheng Zhu Jinping Liu 《Advanced functional materials》2023,33(13):2211412
Aqueous Zn-ion batteries (AZIBs) are promising due to their high theoretical energy density and intrinsic safety, and the natural abundance of Zn. Since low voltage is an intrinsic shortage of AZIBs, achieving super-high capacity of cathode materials is a vital way to realize high practical energy density, which however remains a huge challenge. Herein, the capacity increase of classical vanadium oxide cathode is predicted via designing atomic thickness of 2D structure to introduce abundant Zn2+ storage sites based on density functional theory (DFT) calculation; then graphene-analogous V2O5·nH2O (GAVOH) with only few atomic layers is fabricated, realizing a record capacity of 714 mAh g−1. Pseudocapacitive effect is unveiled to mainly contribute to the super-high capacity due to the highly exposed GAVOH external surface. In situ Raman and synchrotron X-ray techniques unambiguously uncover the Zn2+ storage mechanism. Carbon nanotubes (CNTs) are further introduced to design GAVOH-CNTs gel ink for large-scale cathode fabrication. The hybrid cathode demonstrates ultra-stable cycling and excellent rate capability and delivers a high energy density of 476 Wh kg−1 at 76 W kg−1; 228 Wh kg−1 is still retained at high mass loading of 10.2 mg cm−2. This work provides inspiration for breaking the capacity limit of cathode in AZIBs. 相似文献
66.
67.
随着新能源的大规模集中式并网,新能源的消纳难题愈发突出。作为高比例可再生能源电力系统中的重要组成部分和关键支撑技术,储能的规模化应用有利于提升系统的灵活性、经济性及安全性。然而,当前综述多是侧重于对储能技术归纳总结,很少对储能规划方法,特别是大规模储能在源-网侧配置方法进行全面的梳理。因此,首先对大规模储能纳入电力系统规划后整体影响进行分析,总结归纳出储能在电力系统中的应用场景,并分析储能的引入对规划问题建模的影响;然后,分别从大规模储能源侧/网侧规划以及考虑大规模储能的源网协调规划两个方面展开论述;最后,探讨当前大规模储能规划的重点问题,并对其前景做出展望。 相似文献
68.
69.
本文针对传统远程视频监控系统在安全可靠性上存在的隐患提出了有效的解决方案,并且在大规模网络系统中具有良好的性能。首先本文基于SIP提出了大规模网络中的视频监控结构,然后在此基础上,进行了认证授权、媒体流私密方案和系统管理等方面的设计。通过本文的技术方案,远程视频监控系统中的音视频数据的安全可靠传输能够较好地得以实现。 相似文献
70.