全文获取类型
收费全文 | 4966篇 |
免费 | 586篇 |
国内免费 | 288篇 |
专业分类
电工技术 | 425篇 |
综合类 | 309篇 |
化学工业 | 678篇 |
金属工艺 | 312篇 |
机械仪表 | 356篇 |
建筑科学 | 517篇 |
矿业工程 | 144篇 |
能源动力 | 147篇 |
轻工业 | 341篇 |
水利工程 | 98篇 |
石油天然气 | 310篇 |
武器工业 | 40篇 |
无线电 | 588篇 |
一般工业技术 | 618篇 |
冶金工业 | 267篇 |
原子能技术 | 63篇 |
自动化技术 | 627篇 |
出版年
2024年 | 31篇 |
2023年 | 114篇 |
2022年 | 185篇 |
2021年 | 270篇 |
2020年 | 211篇 |
2019年 | 182篇 |
2018年 | 187篇 |
2017年 | 205篇 |
2016年 | 176篇 |
2015年 | 215篇 |
2014年 | 273篇 |
2013年 | 329篇 |
2012年 | 355篇 |
2011年 | 383篇 |
2010年 | 284篇 |
2009年 | 261篇 |
2008年 | 260篇 |
2007年 | 224篇 |
2006年 | 256篇 |
2005年 | 251篇 |
2004年 | 148篇 |
2003年 | 149篇 |
2002年 | 144篇 |
2001年 | 126篇 |
2000年 | 98篇 |
1999年 | 99篇 |
1998年 | 103篇 |
1997年 | 75篇 |
1996年 | 43篇 |
1995年 | 44篇 |
1994年 | 36篇 |
1993年 | 36篇 |
1992年 | 22篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1959年 | 2篇 |
1943年 | 2篇 |
1935年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有5840条查询结果,搜索用时 31 毫秒
41.
介绍了国内外型焦技术的生产工艺、型煤碳化的过程和影响因素,以及国内目前几种碳化窑炉,通过对型焦和焦炭的对比分析,指出洁净型焦生产技术的优势必然会使它在未来具有巨大的发展空间。 相似文献
42.
43.
Zhenbao Liu Sicong Tang Weiwei Xu Shuhui Bu Junwei Han Kun Zhou 《Computer Graphics Forum》2014,33(7):269-278
Since indoor scenes are frequently changed in daily life, such as re‐layout of furniture, the 3D reconstructions for them should be flexible and easy to update. We present an automatic 3D scene update algorithm to indoor scenes by capturing scene variation with RGBD cameras. We assume an initial scene has been reconstructed in advance in manual or other semi‐automatic way before the change, and automatically update the reconstruction according to the newly captured RGBD images of the real scene update. It starts with an automatic segmentation process without manual interaction, which benefits from accurate labeling training from the initial 3D scene. After the segmentation, objects captured by RGBD camera are extracted to form a local updated scene. We formulate an optimization problem to compare to the initial scene to locate moved objects. The moved objects are then integrated with static objects in the initial scene to generate a new 3D scene. We demonstrate the efficiency and robustness of our approach by updating the 3D scene of several real‐world scenes. 相似文献
44.
挡水结构水下爆炸作用的离心模型试验 总被引:1,自引:0,他引:1
水下爆炸包括冲击波和气泡脉动,两者能量相当,均会对结构产生毁伤作用。水下爆炸载荷试验唯有在离心机内才满足相似关系,设计试验时宜在离心机负载范围内尽可能增加模型尺寸以减小边界效应。针对挡水结构,在离心机内布置压力传感器、高速摄像机、加速度计及应变片测试了冲击波、气泡脉动载荷及结构产生的动力响应。通过试验对比了水下爆炸和空爆产生的载荷,分析其引起结构动力响应的差异。对于水下爆炸,重力加速度的增加引起气泡脉动冲量的减小,而气泡脉动产生的峰值应变基本与气泡冲量呈线性关系,因而模拟气泡脉动对结构作用时应考虑重力效应。 相似文献
45.
Automatically identifying and extracting the target information of a webpage, especially main text, is a critical task in many web content analysis applications, such as information retrieval and automated screen reading. However, compared with typical plain texts, the structures of information on the web are extremely complex and have no single fixed template or layout. On the other hand, the amount of presentation elements on web pages, such as dynamic navigational menus, flashing logos, and a multitude of ad blocks, has increased rapidly in the past decade. In this paper, we have proposed a statistics-based approach that integrates the concept of fuzzy association rules (FAR) with that of sliding window (SW) to efficiently extract the main text content from web pages. Our approach involves two separate stages. In Stage 1, the original HTML source is pre-processed and features are extracted for every line of text; then, a supervised learning is performed to detect fuzzy association rules in training web pages. In Stage 2, necessary HTML source preprocessing and text line feature extraction are conducted the same way as that of Stage 1, after which each text line is tested whether it belongs to the main text by extracted fuzzy association rules. Next, a sliding window is applied to segment the web page into several potential topical blocks. Finally, a simple selection algorithm is utilized to select those important blocks that are then united as the detected topical region (main texts). Experimental results on real world data show that the efficiency and accuracy of our approach are better than existing Document Object Model (DOM)-based and Vision-based approaches. 相似文献
46.
利用 LabVIEW 强大的数据采集、处理和程序设计功能,设计、开发了一款数字存储示波器。它主要是由信号输入模块、数据处理模块和波形显示及存储模块组成,是通过软件编程实现信号的显示和测量等功能的。在虚拟示波器上集成的虚拟信号发生器可以在声卡采集和虚拟信号输入之间切换。实验结果表明,该虚拟示波器基本实现了传统示波器的功能,并且运行可靠、性能良好,能够满足普通实验室正常的使用需求。 相似文献
47.
48.
步扬坚 《网络安全技术与应用》2014,(11):106-106
随着网络技术的不断发展,网络传输的速度越来越快,随之文件的体积也就越来越大,如果局域网内部还是采用传统的HTTP或FTP进行文件传输,就会对服务器性能要求越来越高,这种模式已经不能满足大规模的文件分享和传输,本文设计了基于BT技术的局域网文件传输模型。 相似文献
49.
HA/TCP and HA rods (?5 mm×10 mm) were made for implantation in New Zealand white rabbit with different condition. Sixty three rabbit were divided into three groups: group 1 (n=18), group 2 (n=27) and group 3 (n=18). In group 1, 10 mm radius was defected, and one HA/TCP rod was implanted in the muscle a distant away from the bone defect area. In group 2, also, 10 mm radius was defected, one HA rod was implanted in the muscle a distant away from the bone defect area. In group 3, two HA/TCP rods were implanted in the dorsal muscle of the rabbit with bone intact. Histological observation showed that in group 1, some new bone was found only two months after implantation (n=2), and obvious immature woven bone could be observed in these bioceramics from the 3rd month on. However, in group 3, bone began to be found 6 months after implantation (n=2). In group 2, we could not find any bone tissue up to 9 month’s observation. These results suggest that, first, the bone defect model could significantly accelerate bone formation at non-osseous sites in rabbits; second,. HA/TCP bioceramics were confirmed with osteoinductive property while HA bioceramics without osteoinductive property nearly. Thus, bone defect might be a good animal model for further researches for osteoinductive bioceramics. 相似文献
50.
The synthesis and characterization of fractions of poly(cyclohexylethyl methacrylate) (PCHEM) are reported. A combination
of low-angle laser light scattering and intrinsic viscosity experiments was employed to estimate the characteristic ratio
(C∞) of this polymer. The value of 10.7 obtained for PCHEM is similar to the value of 11.3 found previously for poly(phenylethyl
methacrylate) but is smaller than values measured for poly(cyclohexyl methacrylate) and poly(cyclohexylmethyl methacrylate)
(C∞ = 11.6 and 11.9, respectively).
Received: 28 October 1996/Revised: 16 December 1996/Accepted: 19 December 1996 相似文献