全文获取类型
收费全文 | 129064篇 |
免费 | 12859篇 |
国内免费 | 7478篇 |
专业分类
电工技术 | 9613篇 |
技术理论 | 8篇 |
综合类 | 9746篇 |
化学工业 | 19421篇 |
金属工艺 | 7517篇 |
机械仪表 | 8772篇 |
建筑科学 | 10643篇 |
矿业工程 | 4354篇 |
能源动力 | 3796篇 |
轻工业 | 9039篇 |
水利工程 | 2822篇 |
石油天然气 | 7269篇 |
武器工业 | 1429篇 |
无线电 | 15427篇 |
一般工业技术 | 14004篇 |
冶金工业 | 5293篇 |
原子能技术 | 1596篇 |
自动化技术 | 18652篇 |
出版年
2024年 | 716篇 |
2023年 | 2407篇 |
2022年 | 4598篇 |
2021年 | 6389篇 |
2020年 | 4902篇 |
2019年 | 3756篇 |
2018年 | 4194篇 |
2017年 | 4680篇 |
2016年 | 4052篇 |
2015年 | 5972篇 |
2014年 | 7554篇 |
2013年 | 8587篇 |
2012年 | 9875篇 |
2011年 | 10514篇 |
2010年 | 9280篇 |
2009年 | 8597篇 |
2008年 | 8235篇 |
2007年 | 7448篇 |
2006年 | 6874篇 |
2005年 | 5603篇 |
2004年 | 3812篇 |
2003年 | 2925篇 |
2002年 | 2770篇 |
2001年 | 2287篇 |
2000年 | 2050篇 |
1999年 | 2204篇 |
1998年 | 1696篇 |
1997年 | 1475篇 |
1996年 | 1322篇 |
1995年 | 1085篇 |
1994年 | 873篇 |
1993年 | 623篇 |
1992年 | 525篇 |
1991年 | 358篇 |
1990年 | 274篇 |
1989年 | 213篇 |
1988年 | 168篇 |
1987年 | 109篇 |
1986年 | 89篇 |
1985年 | 52篇 |
1984年 | 46篇 |
1983年 | 35篇 |
1982年 | 42篇 |
1981年 | 30篇 |
1980年 | 38篇 |
1979年 | 22篇 |
1978年 | 3篇 |
1959年 | 15篇 |
1951年 | 11篇 |
1940年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
网络教学作为一种新的辅助教学手段,是目前教学改革主要研究的方向之一。通过对网络教学平台的功能分析,探讨了在网络教学平台上进行教学资源的建设、交流互动教学活动的开展和虚拟实验室的建设,通过应用实践证明,充分利用网络教学平台的优势,能有效地提高课堂教学质量和效率,培养学生的学习能力、实践能力和创新能力。 相似文献
94.
该文报道了一种基于酶级联扩增的电化学核酸适体检测腺苷的新方法。当腺苷存在时,滚环扩增的引物通过E.coli DNA连接酶的作用与通过巯基组装在金电极上的固定探针连接。在pHi29 DNA聚合酶的作用下,滚环扩增反应进行并产生一条与环形探针完全互补的长的单链,然后将大量金纳米粒子标记的核酸探针与滚环扩增的产物杂交。该传感界面电化学行为的结果表明,通过酶级联扩增的方法提高了检测腺苷的阻抗响应灵敏度,且选择性和重现性良好。用于腺苷的检测时,其线性范围为2.0μmol/L~100μmol/L,最低检测浓度为2.0μmol/L,表明该传感界面的设计可作为一种通用方法而有望用于其它目标物的检测。 相似文献
95.
何立民 《单片机与嵌入式系统应用》2013,13(5):1-3
人类社会一直存在着并行不悖的科技与人文的两种文化与文化产业。如今,出现了第三种文化与第三种文化产业。第三种文化产业的思想基础是图灵的可计算原理;其物质基础是微处理器智力内核。第三种文化产业将打破两种文化产业界线,用人工智能与智能化工具等现代科技手段,实现人文文化领域中的艺术创作,这是人类文化领域中已经开始的没有硝烟的产业战争。 相似文献
96.
We consider a class of stochastic Nash equilibrium problems (SNEP). Under some mild conditions, we reformulate the SNEP as a stochastic mixed complementarity problem (SMCP). We apply the well-known sample average approximation (SAA) method to solve the SMCP. We further introduce a semismooth Newton method to solve the SAA problems. The comprehensive convergence analysis is given as well. In addition, we demonstrate the proposed approach on a stochastic Nash equilibrium model in the wholesale gas–oil markets. 相似文献
97.
Lei Zhang Sung-In Choi Soon-Yong Park 《International Journal of Control, Automation and Systems》2013,11(5):1001-1008
Registration of range scans is commonly required in many localization and mapping algorithms. In this paper, we introduce a novel approach called Polar-Cartesian Hybrid Transforms for pair-wise registration of range scans. The proposed algorithm iteratively establishes correspondences by searching the points with closest polar angles in the polar coordinate frame. An angular look-up table is constructed based on the properties of the laser range finder to accelerate the searching procedure. In order to speed up the convergence, we compute the difference of polar range of every matched point pair to select the most contributing correspondences. After the correspondences are determined, the transformation is computed in Cartesian coordinate frame using a point-to-line metric. Combining the advantages of the polar and Cartesian coordinate frames, both robustness and efficiency are greatly improved compared with an up-to-date ICP algorithm. 相似文献
98.
We investigate the dynamics of quantum correlation between two separated qubits trapped in one-dimensional plasmonic waveguide. It is found that for a class of initial states, the quantum discord shows a sudden change phenomenon during the dynamical evolution. Furthermore, we demonstrate that the quantum discord can be enhanced if a proper product of the plasmon wave number and two qubits distance is chosen. Finally, we find that the non-zero quantum discord between two qubits can be created for the states without initial quantum discord during the time evolution of the system. 相似文献
99.
Lei Guo Xingwei Wang Qingyang Song Weigang Hou Fei Yang 《Information Sciences》2008,178(18):3635-3644
With the development of intelligent optical networks and the general multi-protocol label switching (GMPLS) technique, the seamless convergence between IP network and optical network is no longer be a dream but a practical reality. Similar to the Internet, current optical networks have been divided into multiple domains each of which has its own network provider and management policy. Therefore, the development of multi-domain optical networks will be the trend of new-generation intelligent optical networks, and GMPLS-based survivability for multi-domain optical networks will become a hot topic of research in the future. This paper provides a comprehensive review of the existing survivable schemes in multi-domain optical networks and analyzes the shortcomings of current research. Based on previous studies, we present possible challenges and propose new ideas to design efficient survivable schemes to guide the future work of researchers in multi-domain optical networks. 相似文献
100.
Image mosaic construction is about stitching together a number of images about the same scene to construct a single image with a larger field of view. The majority of the previous work was rooted at the use of a single image-to-image mapping termed planar homography for representing the imaged scene. However, the mapping is applicable only to cases where the imaged scene is either a single planar surface, or very distant from the cameras, or imaged under a pure rotation of the camera, and that greatly limits the range of applications of the mosaicking methods. This paper presents a novel mosaicking solution for scenes that are polyhedral (thus consisting of multiple surfaces) and that are pictured possibly in closed range of the camera. The solution has two major advantages. First, it requires only a few correspondences over the entire scene, not correspondences over every surface patch in it to work. Second, it conquers a seemingly impossible task—warping image data of surfaces that are visible in only one of the input images, which we refer to as the singly visible surfaces, to another viewpoint to constitute the mosaic there. We also provide a detail analysis of what determines whether a singly visible surface could be mosaicked or not. Experimental results on real image data are presented to illustrate the performance of the method. 相似文献