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   3897篇
  免费   251篇
  国内免费   12篇
电工技术   37篇
综合类   2篇
化学工业   801篇
金属工艺   180篇
机械仪表   197篇
建筑科学   49篇
矿业工程   4篇
能源动力   170篇
轻工业   308篇
水利工程   5篇
石油天然气   13篇
无线电   527篇
一般工业技术   718篇
冶金工业   760篇
原子能技术   38篇
自动化技术   351篇
  2024年   5篇
  2023年   58篇
  2022年   81篇
  2021年   122篇
  2020年   91篇
  2019年   88篇
  2018年   125篇
  2017年   113篇
  2016年   130篇
  2015年   87篇
  2014年   141篇
  2013年   190篇
  2012年   256篇
  2011年   308篇
  2010年   196篇
  2009年   183篇
  2008年   163篇
  2007年   135篇
  2006年   123篇
  2005年   97篇
  2004年   96篇
  2003年   95篇
  2002年   91篇
  2001年   69篇
  2000年   65篇
  1999年   77篇
  1998年   247篇
  1997年   159篇
  1996年   124篇
  1995年   77篇
  1994年   46篇
  1993年   57篇
  1992年   25篇
  1991年   30篇
  1990年   19篇
  1989年   21篇
  1988年   27篇
  1987年   21篇
  1986年   22篇
  1985年   19篇
  1984年   12篇
  1983年   5篇
  1982年   5篇
  1981年   6篇
  1980年   8篇
  1979年   5篇
  1977年   8篇
  1976年   22篇
  1975年   2篇
  1967年   2篇
排序方式: 共有4160条查询结果,搜索用时 31 毫秒
141.
We report the discovery of aurora kinase inhibitor using the fragment-based virtual screening by multi-docking strategy. Among a number of fragments collected from eMololecules, we found four fragment molecules showing potent activity (>50% at 100 μM) against aurora kinase. Based on the explored fragment scaffold, we selected two compounds in our synthesized library and validated the biological activity against Aurora kinase.  相似文献   
142.
Atomic size differences between constituting elements and the heat of mixing are key factors in designing a metallic glass system. In this study, the effects of atomic size differences and the heat of mixing on the glass-forming ability and the local structure of metallic glasses were studied via molecular dynamic simulations of an ideal system known as the Lennard-Jones embedded-atom method model. The atomic size difference and the heat of mixing of the system were varied by means of the Lennard-Jones parameters. The glass transition behavior was characterized based on the chemical short-range order and by a Voronoi analysis. Our simulations lead to optimized windows of atomic size differences and heat of mixing parameters for metallic glass-forming of the model system. Both a greater negative heat of mixing and a larger atomic size difference are necessary for the enhancement of the glass-forming ability.  相似文献   
143.
Bui  Khac-Hoai Nam  Cho  Jiho  Yi  Hongsuk 《Applied Intelligence》2022,52(3):2763-2774
Applied Intelligence - Traffic forecasting plays an important role of modern Intelligent Transportation Systems (ITS). With the recent rapid advancement in deep learning, graph neural networks...  相似文献   
144.
Advances in material science and nanotechnology have fostered the miniaturization of devices. Over the past two decades, the form-factor of these devices has evolved from 3D rigid, volumetric devices through 2D film-based flexible electronics, finally to 1D fiber electronics (fibertronics). In this regard, fibertronic strategies toward wearable applications (e.g., electronic textiles (e-textiles)) have attracted considerable attention thanks to their capability to impart various functions into textiles with retaining textiles' intrinsic properties as well as imperceptible irritation by foreign matters. In recent years, extensive research has been carried out to develop various functional devices in the fiber form. Among various features, lighting and display features are the highly desirable functions in wearable electronics. This article discusses the recent progress of materials, architectural designs, and new fabrication technologies of fiber-shaped lighting devices and the current challenges corresponding to each device's operating mechanism. Moreover, opportunities and applications that the revolutionary convergence between the state-of-the-art fibertronic technology and age-long textile industry will bring in the future are also discussed.  相似文献   
145.
Searching high capacity cathode materials is one of the most important fields of the research and development of sodium‐ion batteries (SIBs). Here, we report a FeO0.7F1.3/C nanocomposite synthesized via a solution process as a new cathode material for SIBs. This material exhibits a high initial discharge capacity of 496 mAh g?1 in a sodium cell at 50 °C. From the 3rd to 50th cycle, the capacity fading is only 0.14% per cycle (from 388 mAh g?1 at 3rd the cycle to 360 mAh g?1 at the 50th cycle), demonstrating superior cyclability. A high energy density of 650 Wh kg?1 is obtained at the material level. The reaction mechanism studies of FeO0.7F1.3/C with sodium show a hybridized mechanism of both intercalation and conversion reaction.  相似文献   
146.
Mobile Networks and Applications - In this paper, we study the performance of a full-duplex (FD) relay system in vehicle-to-vehicle (V2V) communication. In this relay communication system, the...  相似文献   
147.
148.
Bacterial wilt (BW) disease from Ralstonia solanacearum is a serious disease and causes severe yield losses in chili peppers worldwide. Resistant cultivar breeding is the most effective in controlling BW. Thus, a simple and reliable evaluation method is required to assess disease severity and to investigate the inheritance of resistance for further breeding programs. Here, we developed a reliable leaf-to-whole plant spread bioassay for evaluating BW disease and then, using this, determined the inheritance of resistance to R. solanacearum in peppers. Capsicum annuum ‘MC4′ displayed a completely resistant response with fewer disease symptoms, a low level of bacterial cell growth, and significant up-regulations of defense genes in infected leaves compared to those in susceptible ‘Subicho’. We also observed the spreading of wilt symptoms from the leaves to the whole susceptible plant, which denotes the normal BW wilt symptoms, similar to the drenching method. Through this, we optimized the evaluation method of the resistance to BW. Additionally, we performed genetic analysis for resistance inheritance. The parents, F1 and 90 F2 progenies, were evaluated, and the two major complementary genes involved in the BW resistance trait were confirmed. These could provide an accurate evaluation to improve resistant pepper breeding efficiency against BW.  相似文献   
149.
Vu  Thang X.  Trinh  Anh Vu  Chatzinotas  Symeon  Tran  Xuan Nam 《Wireless Networks》2020,26(6):4403-4410

Edge caching has received much attention as a promising technique to overcome the stringent latency and data-hungry challenges in the future generation wireless networks. Meanwhile, full-duplex (FD) transmission can potentially double the spectral efficiency by allowing a node to receive and transmit at the same frequency band simultaneously. In this paper, we investigate the delivery time performance of a cache-aided FD system, in which an edge node, operates in FD mode, serves users via wireless channels and is equipped with a cache memory. Firstly, we derive a closed-form expression for the average delivery time by taking into account the uncertainties of both backhaul and access wireless channels. The derived analysis allows the examination of the impact of key parameters, e.g., cache size and transmit power. Secondly, a power optimization problem is formulated to minimize the average delivery time. To deal with the non-convexity of the formulated problem, we propose an iterative optimization algorithm based on the bisection method. Finally, numerical results are presented to demonstrate the effectiveness of the proposed algorithm. A significant delivery time reduction is achieved by the proposed optimization compared to the FD reference and half-duplex counterpart.

  相似文献   
150.
We examined the possibility of using aerosol deposition (AD) as a simple, environmentally friendly and dry metallization process capable of acting as an alternative to the electroless and electroplating methods. Silver thick films were fabricated, their characteristics evaluated, and the factors influencing their growth investigated. As a result, silver thick films were successfully fabricated by AD with high deposition rates (10 μm/min) at room temperature. The resistivity of the as-deposited silver thick films was 8–10 times larger than that of the bulk silver. Post-annealing increased the resistivity of the silver films by approximately 2–3 times compared to that of the bulk silver. Microstructural observations revealed an increase in the connectivity between the silver particles after the heat treatments, which reduced the resistivity of the as-deposited silver films.  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