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81.
研究了开源软件的网络结构中3节点子图的显著性,发现软件规模越大局部结构的网络化趋势越显著.树型的3节点子图呈现下降趋势,在封闭的3节点子图中,除部分趋势不显著外,大都呈现上升趋势.根据3节点子图的显著性剖面,软件网络大致可以分为3类,与已发现的4个有向复杂网络超级族中的3个基本一致,大部分软件网络的局部结构与生物网络相... 相似文献
82.
交流电机具有结构简单、制造容易、成本低、容易控制等等特点,在许多场合中逐步取代直流电机,成为电机使用者的首选,但是交流电机的调速系统复杂,在使用上很难达到和直流电机相媲美.文章设计一套基于ARM平台的矢量控制和PID算法的交流电机控制系统,实现对交流电机的精确的控制.系统分为硬件、软件、和上位机界面三部分,硬件电路包括电流采集电流和IGBT电路,软件部分采用C语言开发,使用KEI MDK软件开发工具编程,上位机采用LabVIEW软件编写测试界面,运行PID程序,最终开发出一套用于交流电机调速系统的电机控制. 相似文献
83.
目的 指纹匹配是自动指纹识别系统研究的核心内容之一,匹配算法的好坏直接影响识别系统的效能。目前,大多数点模式匹配算法都依赖于指纹方向场的求取,由于输入的指纹图像存在平移、旋转和尺度变化,因此同一个手指在不同时间获得的指纹图像的方向场是不同的,这不仅增加了计算量,也影响了指纹识别的精度。针对上述问题,提出了无方向的三角形匹配算法。方法 提出的三角形匹配算法是以平面中任意点与一个确定的三角形之间的位置结构稳定性为理论基础的。首先,分别在待识指纹图像和模板指纹图像中确定基准三角形;其次,将各个特征点与基准三角形三个顶点的距离组成有序三数组;最后,利用数组的相等程度对指纹相似度进行匹配判断。结果 采用国际标准测试库FVC2004进行综合性能比对实验,实验结果表明,与其他几种匹配算法相比,本文方法在识别精度上提高了27.97%~33.81%,在比对时间上降低了3%~5%,在不同旋转角度下误匹配率平均降低了约86.63%,对噪声、平移、旋转和形变有足够的适应能力,具有较高的容错能力和鲁棒性。结论 无方向的三角形匹配算法是一种全局模式的算法,该算法不受指纹图像方向及其位置的影响,实现过程简单,识别精度高,平均比对时间少,适用于处理不同类型的图像数据。 相似文献
84.
Baldwin CL 《Ergonomics》2011,54(4):328-337
Matching the perceived urgency of an alert with the relative hazard level of the situation is critical for effective alarm response. Two experiments describe the impact of acoustic and semantic parameters on ratings of perceived urgency, annoyance and alerting effectiveness and on alarm response speed. Within a simulated driving context, participants rated and responded to collision avoidance system (CAS) messages spoken by a female or male voice (experiments 1 and 2, respectively). Results indicated greater perceived urgency and faster alarm response times as intensity increased from -2 dB signal to noise (S/N) ratio to +10 dB S/N, although annoyance ratings increased as well. CAS semantic content interacted with alarm intensity, indicating that at lower intensity levels participants paid more attention to the semantic content. Results indicate that both acoustic and semantic parameters independently and interactively impact CAS alert perceptions in divided attention conditions and this work can inform auditory alarm design for effective hazard matching. Matching the perceived urgency of an alert with the relative hazard level of the situation is critical for effective alarm response. Here, both acoustic and semantic parameters independently and interactively impacted CAS alert perceptions in divided attention conditions. This work can inform auditory alarm design for effective hazard matching. STATEMENT OF RELEVANCE: Results indicate that both acoustic parameters and semantic content can be used to design collision warnings with a range of urgency levels. Further, these results indicate that verbal warnings tailored to a specific hazard situation may improve hazard-matching capabilities without substantial trade-offs in perceived annoyance. 相似文献
85.
大型过程建模的Import/Export解决方案 总被引:4,自引:2,他引:2
文章分析了大型复杂过程的建模需求,基于已研发的企事业过程建模系统EPMS,提出了将Import/Export技术用于大型过程建模的解决方案,通过过程模型的拆分和组装,从而支持过程模型的多人员、异地并行建模模式和过程重用。 相似文献
86.
民航计算机订座系统的备份 总被引:1,自引:1,他引:0
民航计算机订座系统始建于1986年。为了满足国内航空市场的发展,保护国内航空销售市场,抵御国外航空销售系统的渗透,1995年,进行了代理人订座系统(CRS)与航空公司订座系统(ICS)分离,成为相对独立的两套系统。 分离后的代理人订座系统(CRS)主要为代理人提供航空订座服务。随着经济的发展、市场的需要,代理人系统的功能逐渐向旅游领域扩展,增加了酒店客房销售、租车及航空意外保险销售等功能,网上售票及相关旅游销售也蓬勃发展,这些都为代理人提供了更为广泛的服务领域和便捷的服务方式。同时,随着CRS系统与国外航空公司… 相似文献
87.
Kusaka T Ueno M Miki T Kanenishi K Nagai Y Huang CL Okamoto Y Ogawa T Onodera M Itoh S Akiguchi I Sakamoto H 《Microscopy research and technique》2007,70(7):648-655
We investigated whether beta-amyloid (Abeta)-like immunoreactivity was seen in the brains of newborn piglets. The immunoreactivity for Abeta(1-42) and Abeta(1-40) proteins, but not Abeta precursor protein, was present in CD68-positive perivascular cells of the hippocampus and in parts of the meninges. It was colocalized with immunoreactivity for receptor for advanced glycation end product and tumor necrosis factor-alpha. The protein with a molecular mass of 27 kDa, which was recognized by the Abeta antibodies, was identified as triosephosphate isomerase (TPI) with sequence homology to Abeta peptides by N-terminal amino acid sequencing, mass fingerprint analysis using matrix-associated laser desorption/ionization mass spectrometry, and Western blotting. Western blotting assay also revealed that detectable expression of Abeta proteins were not seen in the piglet brains. These findings indicate that TPI with sequence homology to Abeta peptides accumulates in perivascular cells of the microglia/macrophage lineage located around arterial vessels of the newborn piglet hippocampus. 相似文献
88.
Yang G Stewart CV Sofka M Tsai CL 《IEEE transactions on pattern analysis and machine intelligence》2007,29(11):1973-1989
Our goal is an automated 2D-image-pair registration algorithm capable of aligning images taken of a wide variety of natural and man-made scenes as well as many medical images. The algorithm should handle low overlap, substantial orientation and scale differences, large illumination variations, and physical changes in the scene. An important component of this is the ability to automatically reject pairs that have no overlap or have too many differences to be aligned well.We propose a complete algorithm, including techniques for initialization, for estimating transformation parameters, and for automatically deciding if an estimate is correct. Keypoints extracted and matched between images are used to generate initial similarity transform estimates, each accurate over a small region. These initial estimates are rank-ordered and tested individually in succession. Each estimate is refined using the Dual-Bootstrap ICP algorithm, driven by matching of multiscale features. A three-part decision criteria, combining measurements of alignment accuracy, stability in the estimate, and consistency in the constraints, determines whether the refined transformation estimate is accepted as correct. Experimental results on a data set of 22 challenging image pairs show that the algorithm effectively aligns 19 of the 22 pairs and rejects 99.8% of the misalignments that occur when all possible pairs are tried. The algorithm substantially out-performs algorithms based on keypoint matching alone. 相似文献
89.
90.
Restoring warped document images through 3D shape modeling 总被引:2,自引:0,他引:2
Tan CL Zhang L Zhang Z Xia T 《IEEE transactions on pattern analysis and machine intelligence》2006,28(2):195-208
Scanning a document page from a thick bound volume often results in two kinds of distortions in the scanned image, i.e., shade along the "spine" of the book and warping in the shade area. In this paper, we propose an efficient restoration method based on the discovery of the 3D shape of a book surface from the shading information in a scanned document image. From a technical point of view, this shape from shading (SFS) problem in real-world environments is characterized by 1) a proximal and moving light source, 2) Lambertian reflection, 3) nonuniform albedo distribution, and 4) document skew. Taking all these factors into account, we first build practical models (consisting of a 3D geometric model and a 3D optical model) for the practical scanning conditions to reconstruct the 3D shape of the book surface. We next restore the scanned document image using this shape based on deshading and dewarping models. Finally, we evaluate the restoration results by comparing our estimated surface shape with the real shape as well as the OCR performance on original and restored document images. The results show that the geometric and photometric distortions are mostly removed and the OCR results are improved markedly. 相似文献