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   98021篇
  免费   9613篇
  国内免费   5563篇
电工技术   7611篇
技术理论   3篇
综合类   7502篇
化学工业   14370篇
金属工艺   6282篇
机械仪表   6535篇
建筑科学   7479篇
矿业工程   2981篇
能源动力   3044篇
轻工业   6714篇
水利工程   2351篇
石油天然气   4698篇
武器工业   1215篇
无线电   11476篇
一般工业技术   10689篇
冶金工业   4509篇
原子能技术   1269篇
自动化技术   14469篇
  2024年   401篇
  2023年   1364篇
  2022年   2703篇
  2021年   3882篇
  2020年   2967篇
  2019年   2319篇
  2018年   2528篇
  2017年   3158篇
  2016年   2934篇
  2015年   4026篇
  2014年   5093篇
  2013年   5963篇
  2012年   7203篇
  2011年   7635篇
  2010年   7076篇
  2009年   6788篇
  2008年   6612篇
  2007年   6236篇
  2006年   5789篇
  2005年   4957篇
  2004年   3682篇
  2003年   3362篇
  2002年   3436篇
  2001年   3000篇
  2000年   2045篇
  1999年   1702篇
  1998年   1166篇
  1997年   982篇
  1996年   922篇
  1995年   738篇
  1994年   596篇
  1993年   431篇
  1992年   322篇
  1991年   269篇
  1990年   207篇
  1989年   167篇
  1988年   138篇
  1987年   102篇
  1986年   70篇
  1985年   40篇
  1984年   43篇
  1983年   28篇
  1982年   22篇
  1981年   21篇
  1980年   18篇
  1979年   14篇
  1978年   6篇
  1976年   5篇
  1959年   8篇
  1951年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
一种新的覆盖粗糙集及其模糊性度量   总被引:2,自引:0,他引:2  
在覆盖近似空间中定义了一类新的模糊集,给出了该类模糊集的模糊性度量,讨论模糊集及其模糊度量的性质,最后通过实例给出直观解释.  相似文献   
72.
The optimized copyright protection system with genetic watermarking   总被引:1,自引:0,他引:1  
Applications for robust watermarking is one of the major branches in digital rights management (DRM) systems and related researches. Based on existing experiences to evaluate the applicability of robust watermarking, it is generally agreed that three parameters or requirements, including the quality of watermarked contents, the survivability of extracted watermark after deliberate or unintentional attacks, and the number of bits embedded, need to be considered. However, performances relating to these three parameters conflict with each other, and the trade off must be searched for. In this paper, we take all the three requirements into consideration, and add the flexibility to meet the specific design in implementation. With the aid of genetic algorithm, we design an applicable system that would obtain the good quality, acceptable survivability, and reasonable capacity after watermarking. Simulation results present the effectiveness in practical implementation and possible application of the proposed algorithm.  相似文献   
73.
A new algorithm for reducing control points in lofted surface interpolation to rows of data points is presented in this paper. The key step of surface lofting is to obtain a set of compatible B-spline curves interpolating each row. Given a set of points and their parameterization, a necessary and sufficient condition is proposed to determine the existence of interpolating B-spline curves defined on a given knot vector. Based on this condition, we first properly construct a common knot vector that guarantees the existence of interpolating B-spline curves to each row of points. Then we calculate a set of interpolating B-spline curves defined on the common knot vector by energy minimization. Using this method, fewer control points are employed while maintaining a visually pleasing shape of the lofted surface. Several experimental results demonstrate the usability and quality of the proposed method.  相似文献   
74.
75.
文章分析了将过期“双迫”药改制成射钉枪药的可行性.实验表明,改制可采用球形药工艺,制品能满足射钉枪的使用要求.  相似文献   
76.
Following logic in the silicon semiconductor industry, the existence of native oxide and suitable fabrication technology is essential for 2D semiconductors in planar integronics, which are surface-sensitive to typical coating technologies. To date, very few types of integronics are found to possess this feature. Herein, the 2D Bi2O2Te developed recently is reported to possess large-area synthesis and controllable thermal oxidation behavior toward single-crystal native oxides. This shows that surface-adsorbed oxygen atoms are inclined to penetrate across [Bi2O2]n2n+ layers and bond with the underlying [Te]n2n− at elevated temperatures, transforming directly into [TeO4]n2n− with the basic architecture remaining stable. The oxide can be adjusted to form in an accurate layer-by-layer manner with a low-stress sharp interface. The native oxide Bi2TeO6 layer (bandgap of ≈2.9 eV) exhibits visible-light transparency and is compatible with wet-chemical selective etching technology. These advances demonstrate the potential of Bi2O2Te in planar-integrated functional nanoelectronics such as tunnel junction devices, field-effect transistors, and memristors.  相似文献   
77.
Semitransparent organic solar cells (ST-OSCs) have attracted increasing attention due to their promising prospect in building-integrated photovoltaics. Generally, efficient ST-OSCs with good average visible transmittance (AVT) can be realized by developing active layer materials with light absorption far from the visible light range. Herein, the development of ultrawide bandgap polymer donors with near-ultraviolet absorption, paired with near-infrared acceptors, is proposed to achieve high-performance ST-OSCs. The key points for the design of ultrawide bandgap polymers include constructing donor–donor type conjugated skeleton, suppressing the quinoidal resonance effect, and minimizing the twist of conjugated skeleton via noncovalent conformational locks. As a proof of concept, a polymer named PBOF with an optical bandgap of 2.20 eV is synthesized, which exhibited largely reduced overlap with the human eye photopic response spectrum and afforded a power conversion efficiency (PCE) of 16.40% in opaque device. As a result, ST-OSCs with a PCE over 10% and an AVT over 30% are achieved without optical modulation. Moreover, colorful ST-OSCs with visual aesthetics can be achieved by tuning the donor/acceptor weight ratio in active layer benefiting from the ultrawide bandgap nature of PBOF. This study demonstrates the great potential of ultrawide bandgap polymers for efficient colorful ST-OSCs.  相似文献   
78.
Zhang  Man  Zhou  Yong  Liu  Bing  Zhao  Jiaqi  Yao  Rui  Shao  Zhiwen  Zhu  Hancheng  Chen  Hao 《Pattern Analysis & Applications》2023,26(2):669-677
Pattern Analysis and Applications - The designed method aims to perform image classification tasks efficiently and accurately. Different from the traditional CNN-based image classification methods,...  相似文献   
79.
Bi  Jie  Zhang  Yong 《Applied Intelligence》2022,52(6):5966-6006
Applied Intelligence - The henry gas solubility optimization (HGSO) is a new nature-inspired algorithm that mimics Henry Gas Solubility to solve global optimization problems. The main changes of...  相似文献   
80.
Lung cancer is one of the deadliest diseases in the world. Non‐small cell lung cancer (NSCLC) is the most common and dangerous type of lung cancer. Despite the fact that NSCLC is preventable and curable for some cases if diagnosed at early stages, the vast majority of patients are diagnosed very late. Furthermore, NSCLC usually recurs sometime after treatment. Therefore, it is of paramount importance to predict NSCLC recurrence, so that specific and suitable treatments can be sought. Nonetheless, conventional methods of predicting cancer recurrence rely solely on histopathology data and predictions are not reliable in many cases. The microarray gene expression (GE) technology provides a promising and reliable way to predict NSCLC recurrence by analysing the GE of sample cells. This study proposes a new model from GE programming to use microarray datasets for NSCLC recurrence prediction. To this end, the authors also propose a hybrid method to rank and select relevant prognostic genes that are related to NSCLC recurrence prediction. The proposed model was evaluated on real NSCLC microarray datasets and compared with other representational models. The results demonstrated the effectiveness of the proposed model.Inspec keywords: lung, cancer, lab‐on‐a‐chip, genetics, patient diagnosisOther keywords: NSCLC recurrence prediction, microarray data, GE programming, nonsmall cell lung cancer, cancer recurrence, histopathology data, microarray gene expression, prognostic genes  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