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91.
高浓度聚合物驱提高采收率方法实验研究   总被引:3,自引:0,他引:3  
为探索一种新的提高原油采收率的方法,在外形尺寸为4.5 cm×4.5 cm×30 cm、气测渗透率0.9~1.0μm2、变异系数为0.72的二维纵向非均质人造岩心上,模拟大庆油田油藏流体性质及温度条件,研究了高浓度聚合物(HPAM)驱注入时机、聚合物相对分子质量、聚合物段塞体积及段塞组合对驱油效果的影响。通过注入大分子量、高浓度聚合物,结合合理的注入方式,在化学剂成本与三元复合驱相当的情况下,采收率比水驱提高20个百分点以上,接近或超过三元复合驱的水平。实验表明,采用高浓度聚合物驱油是一种较好的提高原油采收率的方法。  相似文献   
92.
最大塑性功原理在烧结体上限分析中的应用   总被引:1,自引:0,他引:1  
秦训鹏  华林 《粉末冶金技术》2006,24(4):248-250,255
最大塑性功原理又称第二塑性变分原理,在致密体塑性变形分析叶l是运用能量法进行变形力能计算的基础。本文从分析Drucker公设的亢要条件出发,证明了烧结体塑性变形最大塑性功原理的存在,片在该原理的荩础卜,推导出塑性变形的上限功率表达式,并以平面挤压条件下的上限法应用作为实例加以说明。  相似文献   
93.
Based on the current spin density functional theory, a theoretical model of three vertically aligned semiconductor quantum dots is proposed and numerically studied. This quantum dot molecule (QDM) model is treated with realistic hard-wall confinement potential and external magnetic field in three-dimensional setting. Using the effective-mass approximation with band nonparabolicity, the many-body Hamiltonian results in a cubic eigenvalue problem from a finite difference discretization. A self-consistent algorithm for solving the Schrödinger-Poisson system by using the Jacobi-Davidson method and GMRES is given to illustrate the Kohn-Sham orbitals and energies of six electrons in the molecule with some magnetic fields. It is shown that the six electrons residing in the central dot at zero magnetic field can be changed to such that each dot contains two electrons with some feasible magnetic field. The Förster-Dexter resonant energy transfer may therefore be generated by two individual QDMs. This may motivate a new paradigm of Fermionic qubits for quantum computing in solid-state systems.  相似文献   
94.
We extend the definition of the classical Jacobi polynomials withindexes α, β>−1 to allow α and/or β to be negative integers. We show that the generalized Jacobi polynomials, with indexes corresponding to the number of boundary conditions in a given partial differential equation, are the natural basis functions for the spectral approximation of this partial differential equation. Moreover, the use of generalized Jacobi polynomials leads to much simplified analysis, more precise error estimates and well conditioned algorithms.Mathematics subject classification 1991. 65N35, 65N22, 65F05, 35J05  相似文献   
95.
An optoelectronic method is considered for noncontacting reconstruction of the surface profile of three-dimensional objects of large dimensions. The optimal conditions for performing measurements are identified. It is shown that the proposed method, in contrast to the already known methods, does not require fine tuning of the equipment. A numerical method is given for compensating distortions caused by aberrations. A method is described for reconstructing the surface profile cell by cell which increases the accuracy of measurements.  相似文献   
96.
The basic methods of verifying continuous automatic belt weighers are described. A comparative analysis of these methods on the basis of experimental studies is made and ways of implementing the results in industry are recommended.  相似文献   
97.
探针馈电圆柱共形微带天线阻抗特性的FDTD法分析   总被引:1,自引:0,他引:1       下载免费PDF全文
将圆柱坐标系下非分裂式理想匹配层吸收边界条件(UPML)引入到圆柱共形微带天线的全波分析中,并给出了其中的场量迭代方程,明显地减小了计算空间,简化了编程;提出了圆柱坐标系下考虑有限尺寸探针半径的新算法,使得计算结果更加精确;应用GPOF方法预估了时域晚时响应,使计算时间减少了70%~90%。本文给出的模型能够对任意多层圆柱共形结构的微带天线进行计算,因此对此类天线的CAD设计具有实际意义。  相似文献   
98.
A Lattice Approach to Image Segmentation   总被引:1,自引:0,他引:1  
After a formal definition of segmentation as the largest partition of the space according to a criterion σ and a function f, the notion of a morphological connection is reminded. It is used as an input to a central theorem of the paper (Theorem 8), that identifies segmentation with the connections that are based on connective criteria. Just as connections, the segmentations can then be regrouped by suprema and infima. The generality of the theorem makes it valid for functions from any space to any other one. Two propositions make precise the AND and OR combinations of connective criteria. The soundness of the approach is demonstrated by listing a series of segmentation techniques. One considers first the cases when the segmentation under study does not involve initial seeds. Various modes of regularity are discussed, which all derive from Lipschitz functions. A second category of examples involves the presence of seeds around which the partition of the space is organized. An overall proposition shows that these examples are a matter for the central theorem. Watershed and jump connection based segmentations illustrate this type of situation. The third and last category of examples deals with cases when the segmentation occurs in an indirect space, such as an histogram, and is then projected back on the actual space under study. The relationships between filtering and segmentation are then investigated. A theoretical chapter introduces and studies the two notions of a pulse opening and of a connected operator. The conditions under which a family of pulse openings can yield a connected filter are clarified. The ability of segmentations to generate pyramids, or hierarchies, is analyzed. A distinction is made between weak hierarchies where the partitions increase when going up in the pyramid, and the strong hierarchies where the various levels are structured as semi-groups, and particularly as granulometric semi-groups. The last section is based on one example, and goes back over the controversy about “lattice” versus “functional” optimization. The problem is now tackled via a case of colour segmentation, where the saturation serves as a cursor between luminance and hue. The emphasis is put on the difficulty of grouping the various necessary optimizations into a single one.  相似文献   
99.
分析指出试井理论和应用之间存在的问题,提出构架试井理论和应用之间桥梁的基础,明确构架桥梁的方法和手段。根据目前国内外试井理论和应用的发展状况,指出试井理论和试井分析方法应用的发展趋势。  相似文献   
100.
基于对比折射法的三维静校正技术及其应用   总被引:7,自引:0,他引:7  
在地形起伏剧烈、速度和厚度横向变化大的地区,折射静校正技术的应用受到诸多限制,主要表现在不能准确地识别和拾取来自于地下连续地质界面的折射波,使得精确求取的长波长静校正量困难。为此,提出了一种基于对比折射法的三维静校正技术。介绍了这种静校正技术的方法原理和特点,基于对比折射法的折射波至拾取实质上是一个折射层的对比分析解释过程,因此能准确地拾取折射波至,精确地求解低速带的绝对延迟时;然后利用延迟时和近地表速度模型(等效,时深,空变)反演表层模型,最终一次性完成基准面静校正(包含低速带校正和高程校正)。在黄土塬、沙漠以及沙漠和山地的接合部等地区,利用基于对比折射法的三维静校正技术进行静校正处理,使资料的品质得到了明显改善,反射同相轴连续性好,信噪比和分辨率高,构造形态清晰可靠,提高了勘探精度。  相似文献   
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