首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   230234篇
  免费   18118篇
  国内免费   9245篇
电工技术   12579篇
技术理论   24篇
综合类   14344篇
化学工业   39041篇
金属工艺   13228篇
机械仪表   14619篇
建筑科学   17684篇
矿业工程   7551篇
能源动力   6455篇
轻工业   13568篇
水利工程   3620篇
石油天然气   16699篇
武器工业   1676篇
无线电   25429篇
一般工业技术   27532篇
冶金工业   12891篇
原子能技术   2268篇
自动化技术   28389篇
  2024年   1001篇
  2023年   3844篇
  2022年   6531篇
  2021年   9166篇
  2020年   7155篇
  2019年   6078篇
  2018年   6806篇
  2017年   7604篇
  2016年   6803篇
  2015年   8934篇
  2014年   11329篇
  2013年   13375篇
  2012年   14341篇
  2011年   15578篇
  2010年   13544篇
  2009年   12810篇
  2008年   12446篇
  2007年   11974篇
  2006年   12436篇
  2005年   10840篇
  2004年   7319篇
  2003年   6289篇
  2002年   5530篇
  2001年   4929篇
  2000年   5464篇
  1999年   6473篇
  1998年   5458篇
  1997年   4464篇
  1996年   4209篇
  1995年   3514篇
  1994年   2826篇
  1993年   1968篇
  1992年   1544篇
  1991年   1229篇
  1990年   938篇
  1989年   745篇
  1988年   544篇
  1987年   338篇
  1986年   284篇
  1985年   196篇
  1984年   140篇
  1983年   115篇
  1982年   124篇
  1981年   99篇
  1980年   72篇
  1979年   38篇
  1978年   27篇
  1977年   20篇
  1976年   35篇
  1973年   13篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
Neural Machine Translation (NMT) is an end-to-end learning approach for automated translation, overcoming the weaknesses of conventional phrase-based translation systems. Although NMT based systems have gained their popularity in commercial translation applications, there is still plenty of room for improvement. Being the most popular search algorithm in NMT, beam search is vital to the translation result. However, traditional beam search can produce duplicate or missing translation due to its target sequence selection strategy. Aiming to alleviate this problem, this paper proposed neural machine translation improvements based on a novel beam search evaluation function. And we use reinforcement learning to train a translation evaluation system to select better candidate words for generating translations. In the experiments, we conducted extensive experiments to evaluate our methods. CASIA corpus and the 1,000,000 pairs of bilingual corpora of NiuTrans are used in our experiments. The experiment results prove that the proposed methods can effectively improve the English to Chinese translation quality.  相似文献   
73.
The microstructure and mechanical properties of Mg–6Zn–1Y and Mg–6Zn–3Y(wt%) alloys under different cooling rates were investigated. The results show that the second dendrite arm spacing(SDAS) of Mg–6Zn–1Y and Mg–6Zn–3Y is reduced by 32 and 30% with increasing cooling rates(Rc) from 10.2 to 23 K/s, which can be predicted using a empirical model of SDAS=68 R 0:45:45cand SDAS=73 R 0c, respectively. The compressive strength of both alloys increases with increasing the cooling rate, which is attributed to the increase of volume fraction(Vf) of secondary phases under high cooling rate. The interaction of the cooling rate and component with SDAS has been theoretically analyzed using interdependence theory.  相似文献   
74.
75.
76.
77.
Han  Jing  Xie  Lun  Liu  Jing  Li  Xue 《Multimedia Tools and Applications》2020,79(23-24):16627-16644
Multimedia Tools and Applications - Understanding human emotions through facial expressions is key enabling technology for interactive robots. Most approaches of facial expression recognition are...  相似文献   
78.
Wan  Huan  Wang  Hui  Scotney  Bryan  Liu  Jun  Ng  Wing W. Y. 《Multimedia Tools and Applications》2020,79(39-40):29327-29352
Multimedia Tools and Applications - In many real-world classification problems there exist multiple subclasses (or clusters) within a class; in other words, the underlying data distribution is...  相似文献   
79.
Frontiers of Information Technology & Electronic Engineering - Reconstruction of a 12-lead electrocardiogram (ECG) from a serial 3-lead ECG has been researched in the past to satisfy the need...  相似文献   
80.
The molecular design of short peptides to achieve a tailor-made functional architecture has attracted attention during the past decade but remains challenging as a result of insufficient understanding of the relationship between peptide sequence and assembled supramolecular structures. We report a hybrid-resolution model to computationally explore the sequence–structure relationship of self-assembly for tripeptides containing only phenylalanine and isoleucine. We found that all these tripeptides have a tendency to assemble into nanofibers composed of laterally associated filaments. Molecular arrangements within the assemblies are diverse and vary depending on the sequences. This structural diversity originates from (1) distinct conformations of peptide building blocks that lead to different surface geometries of the filaments and (2) unique sidechain arrangements at the filament interfaces for each sequence. Many conformations are available for tripeptides in solution, but only an extended β-strand and another resembling a right-handed turn are observed in assemblies. It was found that the sequence dependence of these conformations and the packing of resulting filaments are determined by multiple competing noncovalent forces, with hydrophobic interactions involving Phe being particularly important. The sequence pattern for each type of assembly conformation and packing has been identified. These results highlight the importance of the interplay between conformation, molecular packing, and sequences for determining detailed nanostructures of peptides and provide a detailed insight to support a more precise design of peptide-based nanomaterials.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号