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   2478篇
  免费   116篇
  国内免费   85篇
电工技术   80篇
综合类   135篇
化学工业   439篇
金属工艺   74篇
机械仪表   118篇
建筑科学   128篇
矿业工程   78篇
能源动力   55篇
轻工业   236篇
水利工程   76篇
石油天然气   67篇
武器工业   23篇
无线电   184篇
一般工业技术   273篇
冶金工业   264篇
原子能技术   32篇
自动化技术   417篇
  2023年   9篇
  2022年   28篇
  2021年   25篇
  2020年   41篇
  2019年   30篇
  2018年   37篇
  2017年   46篇
  2016年   46篇
  2015年   64篇
  2014年   87篇
  2013年   177篇
  2012年   156篇
  2011年   179篇
  2010年   150篇
  2009年   168篇
  2008年   180篇
  2007年   174篇
  2006年   138篇
  2005年   131篇
  2004年   103篇
  2003年   71篇
  2002年   43篇
  2001年   40篇
  2000年   34篇
  1999年   27篇
  1998年   28篇
  1997年   34篇
  1996年   36篇
  1995年   37篇
  1994年   31篇
  1993年   17篇
  1992年   23篇
  1991年   17篇
  1990年   16篇
  1989年   13篇
  1988年   10篇
  1987年   16篇
  1986年   21篇
  1985年   16篇
  1984年   14篇
  1983年   11篇
  1982年   13篇
  1980年   11篇
  1979年   11篇
  1978年   9篇
  1977年   11篇
  1976年   10篇
  1974年   8篇
  1973年   12篇
  1972年   9篇
排序方式: 共有2679条查询结果,搜索用时 312 毫秒
1.
2.
In the field of images and imaging, super-resolution (SR) reconstruction of images is a technique that converts one or more low-resolution (LR) images into a highresolution (HR) image. The classical two types of SR methods are mainly based on applying a single image or multiple images captured by a single camera. Microarray camera has the characteristics of small size, multi views, and the possibility of applying to portable devices. It has become a research hotspot in image processing. In this paper, we propose a SR reconstruction of images based on a microarray camera for sharpening and registration processing of array images. The array images are interpolated to obtain a HR image initially followed by a convolution neural network (CNN) procedure for enhancement. The convolution layers of our convolution neural network are 3×3 or 1×1 layers, of which the 1×1 layers are used to improve the network performance particularly. A bottleneck structure is applied to reduce the parameter numbers of the nonlinear mapping and to improve the nonlinear capability of the whole network. Finally, we use a 3×3 deconvolution layer to significantly reduce the number of parameters compared to the deconvolution layer of FSRCNN-s. The experiments show that the proposed method can not only ameliorate effectively the texture quality of the target image based on the array images information, but also further enhance the quality of the initial high resolution image by the improved CNN.  相似文献   
3.
Phosphorodiamidate morpholino oligomers (PMOs) are oligonucleotide analogs that can be used for therapeutic modulation of pre‐mRNA splicing. Similar to other classes of nucleic acid‐based therapeutics, PMOs require delivery systems for efficient transport to the intracellular target sites. Here, artificial peptides based on the oligo(ethylenamino) acid succinyl‐tetraethylenpentamine (Stp), hydrophobic modifications, and an azide group are presented, which are used for strain‐promoted azide‐alkyne cycloaddition conjugation with splice‐switching PMOs. By systematically varying the lead structure and formulation, it is determined that the type of contained fatty acid and supramolecular assembly have a critical impact on the delivery efficacy. A compound containing linolenic acid with three cis double bonds exhibits the highest splice‐switching activity and significantly increases functional protein expression in pLuc/705 reporter cells in vitro and after local administration in vivo. Structural and mechanistic studies reveal that the lipopeptide PMO conjugates form nanoparticles, which accelerate cellular uptake and that the content of unsaturated fatty acids enhances endosomal escape. In an in vitro Duchenne muscular dystrophy exon skipping model using H2K‐mdx52 dystrophic skeletal myotubes, the highly potent PMO conjugates mediate significant splice‐switching at very low nanomolar concentrations. The presented aminoethylene‐lipopeptides are thus a promising platform for the generation of PMO‐therapeutics with a favorable activity/toxicity profile.  相似文献   
4.
一种可替代漂珠的低密度材料   总被引:3,自引:0,他引:3  
漂珠低密度水泥浆由于密度低、强度高、体系稳定而在油田低压易漏层及低压油气层长封固段固井作业中获得了广泛的应用。但近年来,由于漂珠的产量越来越少,油田低成本要求急需开发代替漂珠的新型减轻材料,以满足配制低密度水泥浆的需求。开发了BCL-10S低密度混合减轻材料,其物化性能与漂珠相当,用它作减轻剂配制的低密度水泥浆性能与用漂珠作减轻剂配制的低密度水泥浆性能相媲美,并已经在长庆油田获得了应用。  相似文献   
5.
通过龙潭水电站对励磁装置可控硅元件实施过电压保护改进前后实际效果的分析,介绍了一种有效的过压保护方式.  相似文献   
6.
C60辅助下ZnNiS光催化分解水制备氢气的研究   总被引:2,自引:0,他引:2  
通过在光催化剂掺杂ZnS中加入球笼化合物富勒烯C60,提高了光催化水分解的效率.并采用气相色谱法跟踪反应,发现氢气释放量是未加C60时的4倍多.同时,对该催化反应的机理进行了初步的探讨.  相似文献   
7.
单片机破解的常用方法及应对策略   总被引:2,自引:0,他引:2  
介绍了单片机内部密码破解的常用方法,重点说明了侵入型攻击/物理攻击方法的详细步骤,最后,从应用角度出发,提出了对付破解的几点建议。  相似文献   
8.
Technology can take many forms from the development of sophisticated electronics to the application of basic procedural principles. Technology transfer can also take several forms, however, in this case, it is the transfer of technological principles between application domains that is of primary interest. This paper presents a framework (the Five ‘M’s framework) that can be used to consider the likely success of technology transfer. The framework is based upon a sociotechnical system approach. The framework is illustrated with an evaluation of the introduction of intelligent cruise control into motor vehicles. It is argued that this is a technological concept first developed as an aerospace application in the form of the autopilot. In this case, it is argued that the transfer of this technology in its current form may potentially compromise safety.  相似文献   
9.
This study investigated the ability of the Millon Clinical Multiaxial Inventory--Third Edition (MCMI-III) to discriminate students malingering psychopathology (n=106) from bona fide psychiatric inpatients (n=202). Students were randomly assigned to a fake-bad or an honest-responding condition. Analyses investigated the ability of the modifier indices to discriminate fake-bad group participants from the psychiatric inpatients. Scale X raw cutoff score >178 yielded a positive predictive power (PPP) of 0.0, a negative predictive power (NPP) of 63.1, and a hit rate of 63.1%. Optimal cutoff scores were developed. Scale X Base Rate (BR) >84 provided a PPP of 55.6, an NPP of 72.1, and a hit rate of 65.2%. Scale Y BR  相似文献   
10.
This paper describes an approach, conceptual framework, and software architecture for dynamic reconfiguration of the order picking system. The research and development project was sponsored by the Material Handling Research Center (MHRC), a National Science Foundation sponsored Cooperative Industry/University Research Center. The storage configuration is assumed to be an in-the-aisle order picking system in which stockkeeping units (SKUs) can occupy variable capacity storage locations and stock-splitting is allowed among zones (clusters). The product mix may include multiple product families with different life cycles, correlated demand within families and commonality of demand across families.  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