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   2306篇
  免费   147篇
  国内免费   2篇
电工技术   16篇
综合类   14篇
化学工业   764篇
金属工艺   16篇
机械仪表   28篇
建筑科学   115篇
矿业工程   5篇
能源动力   49篇
轻工业   534篇
水利工程   24篇
石油天然气   8篇
武器工业   1篇
无线电   115篇
一般工业技术   353篇
冶金工业   136篇
原子能技术   3篇
自动化技术   274篇
  2024年   3篇
  2023年   44篇
  2022年   137篇
  2021年   174篇
  2020年   56篇
  2019年   59篇
  2018年   71篇
  2017年   79篇
  2016年   100篇
  2015年   84篇
  2014年   90篇
  2013年   176篇
  2012年   157篇
  2011年   178篇
  2010年   126篇
  2009年   116篇
  2008年   123篇
  2007年   93篇
  2006年   80篇
  2005年   73篇
  2004年   69篇
  2003年   59篇
  2002年   53篇
  2001年   20篇
  2000年   24篇
  1999年   22篇
  1998年   10篇
  1997年   10篇
  1996年   13篇
  1995年   21篇
  1994年   9篇
  1993年   9篇
  1992年   4篇
  1991年   8篇
  1990年   7篇
  1989年   10篇
  1988年   12篇
  1987年   6篇
  1986年   7篇
  1985年   5篇
  1984年   3篇
  1983年   7篇
  1982年   10篇
  1980年   3篇
  1979年   4篇
  1978年   3篇
  1975年   3篇
  1973年   3篇
  1969年   3篇
  1967年   3篇
排序方式: 共有2455条查询结果,搜索用时 15 毫秒
81.
This paper focuses on the development of a fully programmable morphological coprocessor for embedded devices. It is a well-known fact that the majority of morphological processing operations are composed of a (potentially large) number of sequential elementary operators. At the same time, the industrial context induces a high demand on robustness and decision liability that makes the application even more demanding. Recent stationary platforms (PC, GPU, clusters) no more represent a computational bottleneck in real-time vision or image processing applications. However, in embedded solutions such applications still hit computational limits. The morphological co-processing unit (MCPU) replies to this demand. It assembles the previously published efficient dilation/erosion units with geodesic units and ALUs to support a larger collection of morphological operations, from a simple dilation to serial filters involving a geodesic reconstruction step. The coprocessor has been integrated into an FPGA platform running a server that is able to respond to client’s requests over the ethernet. The experimental performance of the MCPU measured on a wide set of operations brings as results in orders of magnitude better than another embedded platform, built around an ARM A9 quad-core processor.  相似文献   
82.
Divertor plasma-facing components of future fusion reactors should be able to withstand heat fluxes of 10-20 MW/m2 in stationary operation. Tungsten blocks with an inner cooling tube made of CuCr1Zr, so-called monoblocks, are potential candidates for such water-cooled components. To increase the strength and reliability of the interface between the W and the cooling tube of a Cu-based alloy (CuCr1Zr), a novel advanced W-fibre/Cu metal matrix composite (MMC) was developed for operation temperatures up to 550 °C. Based on optimization results to enhance the adhesion between fibre and matrix, W fibres (Wf) were chemically etched, coated by physical vapour deposition with a continuously graded W/CuPVD interlayer and then heated to 800 °C. The Wf/Cu MMC was implemented by hot-isostatic pressing and brazing process in monoblock mock-ups reinforcing the interface between the plasma-facing material and the cooling channel. The suitability of the MMC as an efficient heat sink interface for water-cooled divertor components was tested in the high heat flux (HHF) facility GLADIS. Predictions from finite element simulations of the thermal behaviour of the component under loading conditions were confirmed by the HHF tests. The Wf/Cu MMC interlayer of the mock-ups survived cyclic heat loads above 10 MW/m2 without any damage. One W block of each tested mock-up showed stable thermal behaviour at heat fluxes of up to 10.5 MW/m2.  相似文献   
83.
Northern form Dolly Varden (Salvelinus malma malma) have been designated as a species of Special Concern in Canada due to declines in population abundance and potential threats. Concern over detrimental effects of low flows on population abundance prompted research on how variability in discharge regimes influence habitat availability. Habitat suitability indices for prespawning and spawning adult anadromous Dolly Varden from two streams were integrated into a two‐dimensional hydrodynamic habitat model to assess the effect of flow variability on usable habitat. Regional hydrographs were used to identify an ecologically relevant range of flows that provided optimal spawning habitat for these populations and examine the relationship between abundance and discharge. Adults spawned in the tail end of pools at moderate water depths and water velocities, and used pebble‐ to cobble‐sized substrate for building redds; whereas, prespawning adults occupied deeper pools with moderate velocities and used cobble for cover. Model outputs showed that spawning habitat availability was optimized at flow rates between 1.6 and 3.0 m3/s and between 1.0 and 6.0 m3/s in Fish Hole Creek (FHC) and Little Fish Creek, respectively. A positive relationship between flows during the fall spawning period and abundance of the FHC population suggests that higher flows coinciding with optimal habitat availability may have contributed to positive recruitment. To strengthen and refine this habitat–population relationship for Dolly Varden in this area requires investigation of a broader suite of variables associated with environmental regimes and physical habitat in reaches used for spawning.  相似文献   
84.
Lung cancer represents an extremely diffused neoplastic disorder with different histological/molecular features. Among the different lung tumors, non-small-cell lung cancer (NSCLC) is the most represented histotype, characterized by various molecular markers, including the expression/overexpression of the fibroblast growth factor receptor-1 (FGFR1). Thus, FGF/FGFR blockade by tyrosine kinase inhibitors (TKi) or FGF-ligand inhibitors may represent a promising therapeutic approach in lung cancers. In this study we demonstrate the potential therapeutic benefit of targeting the FGF/FGFR system in FGF-dependent lung tumor cells using FGF trapping (NSC12) or TKi (erdafitinib) approaches. The results show that inhibition of FGF/FGFR by NSC12 or erdafitinib induces apoptosis in FGF-dependent human squamous cell carcinoma NCI-H1581 and NCI-H520 cells. Induction of oxidative stress is the main mechanism responsible for the therapeutic/pro-apoptotic effect exerted by both NSC12 and erdafitinib, with apoptosis being abolished by antioxidant treatments. Finally, reduction of c-Myc protein levels appears to strictly determine the onset of oxidative stress and the therapeutic response to FGF/FGFR inhibition, indicating c-Myc as a key downstream effector of FGF/FGFR signaling in FGF-dependent lung cancers.  相似文献   
85.
86.
87.
Edible mushrooms production presents a potential problem for the environment, due to the large amount of waste generated. These wastes contain nitrogenous matter, which could be used as biostimulant in plants. The aim of this work was to study the effect of waste waters, from the mushroom production process, applied at veraison and 1 week later to grapevine leaves, on grape volatile compounds over two vintages. The results evidenced that mushroom water treatment decreased the grape content of certain terpenoids, C13 norisoprenoids, benzenoid compounds and esters, increasing C6 compounds content during the first season. Treated mushroom water application slightly affected grape volatile composition. This was the treatment that least affected the content of grape volatile composition. Few differences were found after the biostimulation during the second vintage. The season was the dominant factor of grape volatile content variation compared to the treatment and their interaction.  相似文献   
88.
Waste from fruits and vegetable processing industry is produced in large quantities worldwide and it contains high levels of lignocellulose, fibre, sugar, bioactive and functional compounds. Their utilisation has become one of the main important and challengeable aspects due to the generation of large quantities of by-products including peels, seeds, leaves and unused flesh in different steps of processing chain. Many researches have validated the waste utilisation as novel, low-cost, economical and natural sources of dietary fibre, antioxidants, pectin, enzymes, organic acids, food additives, essential oils, etc. through different methods of extractions, purifications and fermentations. Though, obtaining these by-products from such a variable substrate requires an understanding of the composition of the polysaccharides and their associations within the overall substrate. Focus on the pineapple fruit, scientific and technological studies have already highlighted and confirmed the potential of better and more profitable markets for pineapple wastes. This review is first of all the collection of previous reports about valorisation of food processing waste, deepening the possibilities of pineapple waste utilisation and to promote the integral exploitation of the by-products rich in bioactive compounds, even as multifunctional food ingredients. More in detail, this review aims at identifying those processes that can be implemented even in disadvantaged areas by means of technologies that allow recovering waste directly on site, thus reducing pollution and providing ingredients/food products with high nutritional values that could be integrated into the diet.  相似文献   
89.
Borrelli  Arianna  Wellmann  Janina 《NTM》2019,27(4):407-417
NTM Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin -  相似文献   
90.
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