全文获取类型
收费全文 | 63493篇 |
免费 | 5951篇 |
国内免费 | 3283篇 |
专业分类
电工技术 | 4245篇 |
技术理论 | 6篇 |
综合类 | 4826篇 |
化学工业 | 10570篇 |
金属工艺 | 3659篇 |
机械仪表 | 3876篇 |
建筑科学 | 4944篇 |
矿业工程 | 1787篇 |
能源动力 | 1675篇 |
轻工业 | 4987篇 |
水利工程 | 1163篇 |
石油天然气 | 3529篇 |
武器工业 | 582篇 |
无线电 | 7520篇 |
一般工业技术 | 7050篇 |
冶金工业 | 2749篇 |
原子能技术 | 972篇 |
自动化技术 | 8587篇 |
出版年
2024年 | 345篇 |
2023年 | 1197篇 |
2022年 | 2248篇 |
2021年 | 2948篇 |
2020年 | 2295篇 |
2019年 | 1876篇 |
2018年 | 2038篇 |
2017年 | 2222篇 |
2016年 | 1951篇 |
2015年 | 2603篇 |
2014年 | 3229篇 |
2013年 | 3715篇 |
2012年 | 4126篇 |
2011年 | 4322篇 |
2010年 | 3942篇 |
2009年 | 3851篇 |
2008年 | 3736篇 |
2007年 | 3524篇 |
2006年 | 3444篇 |
2005年 | 2996篇 |
2004年 | 2023篇 |
2003年 | 1903篇 |
2002年 | 2018篇 |
2001年 | 1741篇 |
2000年 | 1465篇 |
1999年 | 1416篇 |
1998年 | 968篇 |
1997年 | 881篇 |
1996年 | 808篇 |
1995年 | 630篇 |
1994年 | 563篇 |
1993年 | 400篇 |
1992年 | 348篇 |
1991年 | 234篇 |
1990年 | 160篇 |
1989年 | 178篇 |
1988年 | 117篇 |
1987年 | 73篇 |
1986年 | 48篇 |
1985年 | 31篇 |
1984年 | 30篇 |
1983年 | 20篇 |
1982年 | 19篇 |
1981年 | 17篇 |
1980年 | 15篇 |
1979年 | 5篇 |
1959年 | 6篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 184 毫秒
91.
Multimedia Tools and Applications - Sparse representation based classification (SRC) and collaborative representation based classification (CRC) are two well-known methods in representation-based... 相似文献
92.
Universal Access in the Information Society - Helping blind people to build cognitive maps of an environment is one of the aims of several assistive systems. In order to evaluate such assistive... 相似文献
93.
Wang Z Zeng F Li H Ye Z Bai Y Xia W Liang B 《Computer methods and programs in biomedicine》2007,86(1):39-44
Evaluation of renal vasculature was necessary for preoperative donor assessment in living donor kidney transplantation, and the ability to view the vascular imaging in three-dimensional (3D) space should be helpful undoubtedly. Considering the widespread use of personal computer (PC) systems, we aimed to find a handy way to display the anatomy of the renal arterial and venous systems of potential donors on PC-Windows platform. Ten living-related donors were included in this study. Serial computed tomography (CT) images were loaded into Amira 3.1 running on a PC with Windows XP. Following image crop, segmentation and 3D reconstruction, we got the 3D images and the video clips. According to the displays which were confirmed by latter intraoperative findings, eight donors had single renal vessels, one had a left accessory renal artery and one had a right accessory renal artery. This project offered a new approach to evaluate the renal vessel anatomy in living donor kidney transplantation, and it was favorable for accuracy and popularizing. 相似文献
94.
Visual media data such as an image is the raw data representation for many important applications. Reducing the dimensionality of raw visual media data is desirable since high dimensionality degrades not only the effectiveness but also the efficiency of visual recognition algorithms. We present a comparative study on spatial interest pixels (SIPs), including eight-way (a novel SIP detector), Harris, and Lucas‐Kanade, whose extraction is considered as an important step in reducing the dimensionality of visual media data. With extensive case studies, we have shown the usefulness of SIPs as low-level features of visual media data. A class-preserving dimension reduction algorithm (using GSVD) is applied to further reduce the dimension of feature vectors based on SIPs. The experiments showed its superiority over PCA.
相似文献
Chandra KambhamettuEmail: |
95.
96.
97.
In the construction of the filling gob-side entry retaining in a lane, we utilize the self-slide natural phenomenon of a falling gangue in an inclined coal seam goaf. First, we put the falling gangue of goaf above the laneway and made it the main filling material by adopting the measurement of flexible supporting system combined with those of rigid supporting system. Then we made the filling material gunited and solidified to maintain the filling goal of the gob-side entry retaining beside the lane. Considering the law of energy conservation and law of pressure distribution for retaining the active and static soil of the wall, we analyzed the reliability of a gangue blocking facilities and the stability of the filling material in the lane. We analyze the figures to see the stability. The result shows that the gangue block supporting system is reliable, and has been successfully practically applied. 相似文献
98.
一、生态足迹视野下的四大城市发展弊端加拿大不列颠哥伦比亚大学社区与区域规划学院教授WilliamRees(威廉姆?里斯)2012年3月7日在纽卡斯尔大学建筑规划景观学院发表演讲,提出了"可持续性的障碍是什么?为什么我们如梦游一般走入全球生态危机之中?"的设问。他从生态足迹分析角度,指出了现代城市 相似文献
99.
100.
Neural tree model has been successfully applied to solving a variety of interesting problems. In most previous studies, optimization
of the neural tree model was divided into two steps: first structure optimization, then parameter optimization. One major
problem in the evolution of structure without parameter information was noisy fitness evaluation. In this paper, an improved
breeder genetic programming algorithm is proposed to the synthesis of neural tree model. The effectiveness and performance
of the method are evaluated on time series prediction problems and compared with those of related methods. Simulation results
show that the proposed algorithm is a potential method with better performance and effectiveness. 相似文献