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   8985篇
  免费   412篇
  国内免费   11篇
电工技术   121篇
综合类   38篇
化学工业   2272篇
金属工艺   228篇
机械仪表   186篇
建筑科学   604篇
矿业工程   20篇
能源动力   287篇
轻工业   842篇
水利工程   88篇
石油天然气   43篇
武器工业   1篇
无线电   669篇
一般工业技术   1490篇
冶金工业   630篇
原子能技术   62篇
自动化技术   1827篇
  2023年   85篇
  2022年   203篇
  2021年   336篇
  2020年   188篇
  2019年   201篇
  2018年   271篇
  2017年   234篇
  2016年   316篇
  2015年   233篇
  2014年   340篇
  2013年   627篇
  2012年   485篇
  2011年   624篇
  2010年   431篇
  2009年   504篇
  2008年   459篇
  2007年   412篇
  2006年   342篇
  2005年   295篇
  2004年   275篇
  2003年   259篇
  2002年   192篇
  2001年   139篇
  2000年   137篇
  1999年   122篇
  1998年   152篇
  1997年   140篇
  1996年   110篇
  1995年   85篇
  1994年   86篇
  1993年   88篇
  1992年   64篇
  1991年   62篇
  1990年   62篇
  1989年   73篇
  1988年   55篇
  1987年   47篇
  1986年   56篇
  1985年   55篇
  1984年   64篇
  1983年   44篇
  1982年   38篇
  1981年   37篇
  1980年   40篇
  1979年   33篇
  1978年   34篇
  1977年   34篇
  1976年   42篇
  1975年   40篇
  1973年   37篇
排序方式: 共有9408条查询结果,搜索用时 0 毫秒
101.
Thesauri and controlled vocabularies facilitate access to digital collections by explicitly representing the underlying principles of organization. Translation of such resources into multiple languages is an important component for providing multilingual access. However, the specificity of vocabulary terms in most thesauri precludes fully-automatic translation using general-domain lexical resources. In this paper, we present an efficient process for leveraging human translations to construct domain-specific lexical resources. This process is illustrated on a thesaurus of 56,000 concepts used to catalog a large archive of oral histories. We elicited human translations on a small subset of concepts, induced a probabilistic phrase dictionary from these translations, and used the resulting resource to automatically translate the rest of the thesaurus. Two separate evaluations demonstrate the acceptability of the automatic translations and the cost-effectiveness of our approach.
Jimmy LinEmail:
  相似文献   
102.
DuD Recht     

DuD Recht

DuD Recht  相似文献   
103.
Controlling aberrant protein kinase activity is a promising strategy for a variety of diseases, particularly cancer. Hence, the development of kinase inhibitors is currently a focal point for pharmaceutical research. In this study we utilize a chip-based reverse phase protein array (RPA) platform for profiling of kinase inhibitors in cell-based assays. In combination with the planar wave-guide technology the assay system has an absolute LOD down to the low zeptomole range. A431 cell lysates were analyzed for the activation state of key effectors in the epidermal growth factor (EGF) and insulin signaling pathways to validate this model for compound screening. A microtiter-plate format for growing, treating, and lysing cells was shown to be suitable for this approach, establishing the value of the technology as a screening tool for characterization of large numbers of kinase inhibitors against a wide variety of cellular signaling pathways. Moreover, the reverse array format allows rapid development of site-specific phosphorylation assays, since in contrast to ELISA type systems only a single antigen-specific antibody is required.  相似文献   
104.
Visualization plays a crucial role in molecular and structural biology. It has been successfully applied to a variety of tasks, including structural analysis and interactive drug design. While some of the challenges in this area can be overcome with more advanced visualization and interaction techniques, others are challenging primarily due to the limitations of the hardware devices used to interact with the visualized content. Consequently, visualization researchers are increasingly trying to take advantage of new technologies to facilitate the work of domain scientists. Some typical problems associated with classic 2D interfaces, such as regular desktop computers, are a lack of natural spatial understanding and interaction, and a limited field of view. These problems could be solved by immersive virtual environments and corresponding hardware, such as virtual reality head-mounted displays. Thus, researchers are investigating the potential of immersive virtual environments in the field of molecular visualization. There is already a body of work ranging from educational approaches to protein visualization to applications for collaborative drug design. This review focuses on molecular visualization in immersive virtual environments as a whole, aiming to cover this area comprehensively. We divide the existing papers into different groups based on their application areas, and types of tasks performed. Furthermore, we also include a list of available software tools. We conclude the report with a discussion of potential future research on molecular visualization in immersive environments.  相似文献   
105.
106.
107.
The growing demand of flexible electronic devices is increasing the requirements of their power sources. The effect of bending in thin-film batteries is still not well understood. Here, we successfully developed a high active area flexible all-solid-state battery as a model system that consists of thin-film layers of Li4Ti5O12, LiPON, and Lithium deposited on a novel flexible ceramic substrate. A systematic study on the bending state and performance of the battery is presented. The battery withstands bending radii of at least 14 mm achieving 70% of the theoretical capacity. Here, we reveal that convex bending has a positive effect on battery capacity showing an average increase of 5.5%, whereas concave bending decreases the capacity by 4% in contrast with recent studies. We show that the change in capacity upon bending may well be associated to the Li-ion diffusion kinetic change through the electrode when different external forces are applied. Finally, an encapsulation scheme is presented allowing sufficient bending of the device and operation for at least 500 cycles in air. The results are meant to improve the understanding of the phenomena present in thin-film batteries while undergoing bending rather than showing improvements in battery performance and lifetime.  相似文献   
108.
In medical technology, implants are used to improve the quality of patients’ lives. The development of materials with adapted properties can further increase the benefit of implants. If implants are only needed temporarily, biodegradable materials are beneficial. In this context, iron-based materials are promising due to their biocompatibility and mechanical properties, but the degradation rate needs to be accelerated. Apart from alloying, the creation of noble phases to cause anodic dissolution of the iron-based matrix is promising. Due to its high electrochemical potential, immiscibility with iron, biocompatibility, and antibacterial properties, silver is suited for the creation of such phases. A suitable technology for processing immiscible material combinations is powder-bed-based procedure like laser beam melting. This procedure offers short exposure times to high temperatures and therefore a limited time for diffusion of alloying elements. As the silver phases remain after the dissolution of the iron matrix, a modification is needed to ensure their degradability. Following this strategy, pure iron with 5 wt% of a degradable silver–calcium–lanthanum alloy is processed via laser beam melting. Investigation of the microstructure yields achievement of the intended microstructure and long-term degradation tests indicates an impact on the degradation, but no increased degradation rate.  相似文献   
109.
By increasing the density of interfaces in NiAl–CrMo in situ composites, the mechanical properties can be significantly improved compared to conventionally cast material. The refined microstructure is achieved by manufacturing through electron beam powder bed fusion (PBF-EB). By varying the process parameters, an equiaxed or columnar cell morphology can be obtained, exhibiting a plate-like or an interconnected network of the (Cr,Mo) reinforcement phase which is embedded in a NiAl matrix. The microstructure of the different cell morphologies is investigated in detail using scanning electron microscope, transmission electron microscopy, and atom probe tomography. For both morphologies, the mechanical properties at elevated temperatures are analyzed by compression and creep experiments parallel and perpendicular to the building direction. In comparison to cast NiAl and NiAl–(Cr, Mo), the yield strength of the PBF-EB fabricated specimens is significantly improved at temperatures up to 1,027 °C. While the columnar morphology exhibits the best improved mechanical properties at high temperatures, the equiaxial morphology shows nearly ideal isotropic mechanical behavior, which is a substantial advantage over directionally solidified material.  相似文献   
110.
Combining make to order and make to stock   总被引:6,自引:0,他引:6  
In inventory control and production planning one is tempted to use one of two strategies: produce all demand to stock or produce all demand to order. The disadvantages are well-known. In the make everything to order case (MTO) the response times may become quite long if the load is high, in the make everything to stock case (MTS) one gets an enormous inventory if the number of different products is large.In this paper we study two simple models which combine MTO and MTS, and investigate the effect of combining MTO and MTS on the production lead times.  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