全文获取类型
收费全文 | 64008篇 |
免费 | 5785篇 |
国内免费 | 2890篇 |
专业分类
电工技术 | 3646篇 |
技术理论 | 2篇 |
综合类 | 4127篇 |
化学工业 | 10729篇 |
金属工艺 | 3731篇 |
机械仪表 | 4123篇 |
建筑科学 | 4778篇 |
矿业工程 | 2144篇 |
能源动力 | 1695篇 |
轻工业 | 4007篇 |
水利工程 | 1081篇 |
石油天然气 | 3969篇 |
武器工业 | 524篇 |
无线电 | 7732篇 |
一般工业技术 | 7792篇 |
冶金工业 | 3077篇 |
原子能技术 | 645篇 |
自动化技术 | 8881篇 |
出版年
2024年 | 358篇 |
2023年 | 1139篇 |
2022年 | 1850篇 |
2021年 | 2621篇 |
2020年 | 1991篇 |
2019年 | 1783篇 |
2018年 | 1937篇 |
2017年 | 2125篇 |
2016年 | 1937篇 |
2015年 | 2498篇 |
2014年 | 3036篇 |
2013年 | 3641篇 |
2012年 | 4071篇 |
2011年 | 4478篇 |
2010年 | 3695篇 |
2009年 | 3537篇 |
2008年 | 3407篇 |
2007年 | 3310篇 |
2006年 | 3678篇 |
2005年 | 3044篇 |
2004年 | 2132篇 |
2003年 | 1810篇 |
2002年 | 1601篇 |
2001年 | 1448篇 |
2000年 | 1565篇 |
1999年 | 1733篇 |
1998年 | 1520篇 |
1997年 | 1272篇 |
1996年 | 1154篇 |
1995年 | 963篇 |
1994年 | 838篇 |
1993年 | 576篇 |
1992年 | 433篇 |
1991年 | 369篇 |
1990年 | 264篇 |
1989年 | 213篇 |
1988年 | 185篇 |
1987年 | 121篇 |
1986年 | 99篇 |
1985年 | 61篇 |
1984年 | 32篇 |
1983年 | 22篇 |
1982年 | 30篇 |
1981年 | 17篇 |
1980年 | 21篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 14篇 |
1975年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
901.
Xiaoying Cheng Xuyang Cao Zhenyu Wu Zhiping Ying Duncan Camilleri Xudong Hu 《Advanced Engineering Materials》2023,25(19):2300341
Carbon fiber-reinforced polymer (CFRP) materials are widely applied in various areas as key structure components. The structural health monitoring of the CFRP components is crucial to prevent catastrophic failure. However, the nonplane surfaces of CFRP components hinder the attaching of monitoring sensors with hard substrates. Therefore, the substrate conditions for sensor preparation are mainly considered in this study. To adapt the proposed sensors to the curved substrate, including nondevelopable surfaces, electrospinning method is used to prepare conformal piezoresistive fiber films, in which polymethyl methacrylate is served as the matrix and carbon nanotubes are utilized as the conductive filler. The piezoresistive fibers covered on CFRP substrates have a gauge factor up to 207.95 and can response to the strain less than 0.05%. Moreover, the sensor also has high durability and the ability to follow the dynamic excitation signals with as high as 50 Hz. 相似文献
902.
Shijie Hu Xiaoyu Li Jiayu Bai Hang Lei Weizhong Qian Sunqiang Hu Cong Zhang Akpatsa Samuel Kofi Qian Qiu Yong Zhou Shan Yang 《计算机、材料和连续体(英文)》2023,74(2):2803-2815
When the Transformer proposed by Google in 2017, it was first used for machine translation tasks and achieved the state of the art at that time. Although the current neural machine translation model can generate high quality translation results, there are still mistranslations and omissions in the translation of key information of long sentences. On the other hand, the most important part in traditional translation tasks is the translation of key information. In the translation results, as long as the key information is translated accurately and completely, even if other parts of the results are translated incorrect, the final translation results’ quality can still be guaranteed. In order to solve the problem of mistranslation and missed translation effectively, and improve the accuracy and completeness of long sentence translation in machine translation, this paper proposes a key information fused neural machine translation model based on Transformer. The model proposed in this paper extracts the keywords of the source language text separately as the input of the encoder. After the same encoding as the source language text, it is fused with the output of the source language text encoded by the encoder, then the key information is processed and input into the decoder. With incorporating keyword information from the source language sentence, the model’s performance in the task of translating long sentences is very reliable. In order to verify the effectiveness of the method of fusion of key information proposed in this paper, a series of experiments were carried out on the verification set. The experimental results show that the Bilingual Evaluation Understudy (BLEU) score of the model proposed in this paper on the Workshop on Machine Translation (WMT) 2017 test dataset is higher than the BLEU score of Transformer proposed by Google on the WMT2017 test dataset. The experimental results show the advantages of the model proposed in this paper. 相似文献
903.
Yahuan Huan Tiantian Luo Xiaocang Han Jun Ge Fangfang Cui Lijie Zhu Jingyi Hu Feipeng Zheng Xiaoxu Zhao Lili Wang Jian Wang Yanfeng Zhang 《Advanced materials (Deerfield Beach, Fla.)》2023,35(1):2207276
Exploring new-type 2D magnetic materials with high magnetic transition temperature and robust air stability has attracted wide attention for developing innovative spintronic devices. Recently, intercalation of native metal atoms into the van der Waals gaps of 2D layered transition metal dichalcogenides (TMDs) has been developed to form 2D non-layered magnetic TMDs, while only succeeded in limited systems (e.g., Cr2S3, Cr5Te8). Herein, composition-controllable syntheses of 2D non-layered iron selenide nanosheets (25% Fe-intercalated triclinic Fe5Se8 and 50% Fe-intercalated monoclinic Fe3Se4) are firstly reported, via a robust chemical vapor deposition strategy. Specifically, the 2D Fe5Se8 exhibits intrinsic room-temperature ferromagnetic property, which is explained by the change of electron spin states from layered 1T'-FeSe2 to non-layered Fe-intercalated Fe5Se8 based on density functional theory calculations. In contrast, the ultrathin Fe3Se4 presents novel metallic features comparable with that of metallic TMDs. This work hereby sheds light on the composition-controllable synthesis and fundamental property exploration of 2D self-intercalation induced novel TMDs compounds, by propelling their application explorations in nanoelectronics and spintronics-related fields. 相似文献
904.
在目前的原燃料条件下,为保证马钢2500m3高炉炉渣具有良好的流动性和较高的脱硫能力,炉渣的CaO/SiO2应控制在1.05至1.15之间,炉渣温度不低于1450℃. 相似文献
905.
利用8~21结点块体单元离散了3号进水塔,对5种工况进行了静动力分析,通过了11个断面的内力值和闸室侧墙的应力状态计算,得出一些可作为设计依据的有益结论。 相似文献
906.
建立了包括有源电力滤波器(APF)在内的公共连接点(PCC)的数学模型;针对实际控制器计算过程中的时间延迟,提出对负载电流值进行预测的两种算法,对逆变器的开关元件提出一种新型脉宽调制(PWM)控制方案,并采用电力电子仿真软件包进行了仿真验证。 相似文献
907.
泵送混凝土技术专家系统的配合比设计研究 总被引:3,自引:0,他引:3
在目前常用的以强度为主要设计指标的基础上,结合考虑砼的可泵性,利用现代先进的计算机技术建立了泵送砼技术专家系统的配合比设计子系统。本文从设计思想、系统的结构与功能、系统的设计过程等方面对泵送砼专家系统的配合比设计子系统进行了介绍。 相似文献
908.
系统分析了容栅式位移传感器的软硬件资源和8031单片机的相关特性,论述了传感器与PC机接口的硬件设计和软件设计方法,并给出了实测数据. 相似文献
909.
以“文后参考文献著录规则”国家标准GB7714-87为依据,对书刊中常用的“顺序编码制”和“著者 出版年制”两种著录方法分别进行了综述,并给出了实例. 相似文献
910.
研究了有机杂质甲醛、甲醇以及其它低级醇对丁炔二醇催化氢化的影响 ;并根据实验数据计算出氢化反应的动力学参数 ,为放大实验及工业设计提供参考数据。 相似文献