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   205篇
  免费   7篇
电工技术   1篇
综合类   2篇
化学工业   29篇
金属工艺   1篇
机械仪表   4篇
建筑科学   9篇
矿业工程   1篇
能源动力   6篇
轻工业   8篇
水利工程   1篇
无线电   37篇
一般工业技术   40篇
冶金工业   33篇
原子能技术   2篇
自动化技术   38篇
  2023年   2篇
  2022年   4篇
  2021年   4篇
  2020年   5篇
  2019年   6篇
  2018年   4篇
  2017年   7篇
  2016年   5篇
  2015年   6篇
  2014年   6篇
  2013年   9篇
  2012年   11篇
  2011年   12篇
  2010年   6篇
  2009年   11篇
  2008年   10篇
  2007年   11篇
  2006年   18篇
  2005年   9篇
  2004年   6篇
  2003年   4篇
  2002年   6篇
  2001年   5篇
  2000年   3篇
  1999年   5篇
  1998年   7篇
  1997年   7篇
  1996年   4篇
  1993年   1篇
  1988年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1981年   2篇
  1979年   2篇
  1976年   6篇
  1975年   1篇
  1972年   2篇
  1966年   1篇
排序方式: 共有212条查询结果,搜索用时 31 毫秒
11.
Cellulosic films are typically sensitive towards moisture which limits their industrial applicability. In this study the films made from cellulose nanofibrils (CNF) were surface silylated with hexamethyldisiloxane (HMDSO) by roll-to-roll plasma deposition. The effects on surface hydrophobicity were clear and indisputable. Water contact angles of non-modified and plasma-deposited CNF films were 23° and 103°, respectively. As a result of surface silylation the relative polarity decreased from 46.8% to 0.6%. Surface hydrophobicity correlated well with the plasma deposition line speeds (0.5, 5, and 10 m/min) and the water vapor barrier properties. Silylation also decreased the oxygen transmission rates both at 50% and 80% relative humidity as compared to non-modified CNF films. All films were completely impermeable to olive oil and intact in contact with castor oil, toluene, and n-heptane or mixtures of them. The developed surface hydrophobization method can be exploited in strengthening the position of cellulosic films in high performance film applications.  相似文献   
12.
Antibody–drug conjugates (ADCs) are promising alternatives to naked antibodies for selective drug‐delivery applications and treatment of diseases such as cancer. Construction of ADCs relies upon site‐selective, efficient and mild conjugation technologies. The choice of a chemical linker is especially important, as it affects the overall properties of the ADC. We envisioned that hydrophilic bifunctional chemical linkers based on carbohydrates would be a useful class of derivatization agents for the construction of linker–drug conjugates and ADCs. Herein we describe the synthesis of carbohydrate‐based derivatization agents, glycolinker–drug conjugates featuring the tubulin inhibitor monomethyl auristatin E and an ADC based on an anti‐EGFR antibody. In addition, an initial in vitro cytotoxicity evaluation of the individual components and the ADC is provided against EGFR‐positive cancer cells.  相似文献   
13.
An open source subcatchment generator program was developed for the Stormwater Management Model (SWMM) to automate tedious stages in the model construction process. The generator divides the investigated area into subcatchments using a uniform computation grid and connects the grid cells together and to the underlying stormwater network. The system was tested by applying it to two small urban catchments with different fractions of impervious surfaces in Helsinki, Finland, using mostly openly available data. The simulated discharge results were compared to measured data and to results obtained from manually built models. The proposed system significantly accelerated the setup of a SWMM modelling project, as the routing between the subcatchments as well as the subcatchment slopes and flow widths were directly derived from the computation grid. Automatically generated and manually constructed SWMM models produced discharge results that differed only slightly from each other.  相似文献   
14.
The embedded-object concept, EOC, applies common object-oriented software methods to Lego-like hardware-software entities. These modular entities, representing objects in object-oriented design, function as electronic building blocks that can be assembled into new embedded systems. The goal of the EOC is to make embedded-system design faster and easier while preserving the commercial applicability of the resulting devices.  相似文献   
15.
Ambient occlusion has proven to be a useful tool for producing realistic images, both in offline rendering and interactive applications. In production rendering, ambient occlusion is typically computed by casting a large number of short shadow rays from each visible point, yielding unparalleled quality but long rendering times. Interactive applications typically use screen‐space approximations which are fast but suffer from systematic errors due to missing information behind the nearest depth layer. In this paper, we present two efficient methods for calculating ambient occlusion so that the results match those produced by a ray tracer. The first method is targeted for rasterization‐based engines, and it leverages the GPU graphics pipeline for finding occlusion relations between scene triangles and the visible points. The second method is a drop‐in replacement for ambient occlusion computation in offline renderers, allowing the querying of ambient occlusion for any point in the scene. Both methods are based on the principle of simultaneously computing the result of all shadow rays for a single receiver point.  相似文献   
16.
The application of nonlinear anisotropic diffusion filtering to reduce noise and enhance contours in images obtained by two-dimensional planar laser-induced fluorescence (PLIF) spectroscopy is presented. In this process the diffusion coefficient is locally adapted, becoming negligible as object boundaries are approached. Noise is efficiently removed, and object contours are strongly enhanced. The technique is demonstrated with PLIF images obtained from the OH radical recorded in turbulent flames. We show that nonlinear diffusion is suitable as a preprocessing step, before image segmentation becomes possible, and we demonstrate how the technique is applied for the quantitative extraction of flame reaction boundaries from PLIF data.  相似文献   
17.
Third-generation mobile radio networks, often dubbed as 3G, have been under intense research and discussion recently and will emerge around the year 2000. In the International Telecommunications Union (ITU), third generation networks are called International Mobile Telecommunications-2000 (IMT-2000), and in Europe, Universal Mobile Telecommunications System (UMTS). IMT-2000 will provide a multitude of services, especially multimedia and high-bit-rate packet data. Wideband code division multiple access (CDMA) has emerged as the mainstream air interface solution for the third-generation networks. In Europe, Japan, Korea, and the United States, wideband CDMA systems are currently being standarized. This article provides a comprehensive introduction to wideband CDMA. It also provides a review of the wideband CDMA air interface proposals including WCDMA in Europe and Japan, cdma2000 in the United States, and wideband CDMA in Korea.  相似文献   
18.
The crystallographic textures and the resulting plastic anisotropy of five interstitial-free (IF) steels with different carbon equivalents and Nb and Ti microalloying content have been investigated. The steels were industrially hot rolled, cold rolled, annealed, and finally hot-dip galvanized. An alternative heat treatment of the cold rolled samples was conducted in laboratory scale using parameters close to those in industry-scale continuous annealing lines. The anisotropy parameters were both measured and predicted on the basis of the measured texture data. The calculated values were corrected by using functions that were fitted to the experimental data. It was found that for a given hot and cold rolling state even minor changes in the annealing conditions can improve the anisotropy parameter by up to 13 pct. Increase in recrystallization texture and improvement of the resulting anisotropy parameters are discussed in terms of partial transformation of ferrite to austenite in the intercritical regime.  相似文献   
19.
A novel approach to synthesize carbon nanofibers (CNFs) directly on the surface of metal μm-sized particles to evenly disperse the carbon nanomaterials in a composite material was proposed. As a metal matrix, 5–10 μm copper particles were utilized. As a carbon source, C2H2, CH4 and CO were examined. The best conditions were found to be in C2H2 (30 cm3/min) and H2 (260 cm3/min) atmosphere at the temperature of 750 °C. The composites based on copper and CNFs prepared by vacuum hot pressing showed the increase in hardness from 35 to 60 kg/mm2 almost retaining pure copper electrical properties.  相似文献   
20.
The present work tested whether ecological and biological variables have an influence on the assimilation of trace elements by the tissues of a cetacean from the Western South Atlantic Ocean. No significant differences were observed in the concentrations for both sexes. As individuals from the two sampling areas belong to distinct genetic and morphological populations, animals of similar body length were older on the southeastern than on the southern coast. The liver showed the highest concentrations of mercury, whereas the highest levels of cadmium were found in the kidney. Hepatic mercury, cadmium and selenium in individuals from the south coast were about four times as high as those from the southeast coast. However, arsenic in the liver and kidney were similar in both coastal areas. Hepatic mercury, cadmium and selenium concentrations increased with body length in individuals from the southeastern coast, although no significant correlations (P>0.05) were observed between body length from either area and the renal and hepatic As concentrations. A significant positive linear relationship was observed between molar concentrations of Hg and Se in the liver of all individuals from both areas (r2=0.93; P<0.001), presenting Se:Hg ratios close to 4. Differences found among the concentrations of Hg, Cd and Se in dolphins from both areas were probably due to the preferred prey, bioavailability of elements in each marine environment, and environment variables (water temperature, net primary production). As a consequence, concentrations of trace elements in the tissues of this species can be considered to be a result of the surrounding environment.  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