全文获取类型
收费全文 | 426篇 |
免费 | 29篇 |
国内免费 | 2篇 |
专业分类
综合类 | 1篇 |
化学工业 | 120篇 |
金属工艺 | 3篇 |
机械仪表 | 11篇 |
建筑科学 | 16篇 |
能源动力 | 33篇 |
轻工业 | 48篇 |
水利工程 | 3篇 |
石油天然气 | 5篇 |
无线电 | 14篇 |
一般工业技术 | 83篇 |
冶金工业 | 38篇 |
原子能技术 | 5篇 |
自动化技术 | 77篇 |
出版年
2023年 | 7篇 |
2022年 | 18篇 |
2021年 | 24篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 13篇 |
2017年 | 10篇 |
2016年 | 15篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 24篇 |
2012年 | 29篇 |
2011年 | 41篇 |
2010年 | 31篇 |
2009年 | 22篇 |
2008年 | 15篇 |
2007年 | 19篇 |
2006年 | 17篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 12篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 11篇 |
1997年 | 9篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1978年 | 2篇 |
排序方式: 共有457条查询结果,搜索用时 31 毫秒
41.
E.C. Montenegro 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1989,280(2-3):332-337
The possibilities of using X-rays in the selection of channels participating in the electron capture process is analyzed. Attention is focused on collisions with bare ions in the intermediate-velocity regime and on the possibilities to obtain single-electron cross sections from coincidence measurements between the target (or projectile) X-rays and the emergent-projectile charge states. 相似文献
42.
43.
Black liquors produced by pulping different wood species can have different corrosivity towards carbon steel equipment in pulp mills. Inorganic constituents of black liquor alone do not correlate well with the corrosivity of different black liquors. Organic constituents of the black liquor have significant effect on determining its corrosivity. However, understanding of the role of individual organic constituents or group of constituents of black liquors in overall black liquor corrosivity is generally lacking. The objective of this study was to determine the effect selected wood species on the corrosivity of their black liquors which contained similar inorganic constituents. The role of black liquor constituent, pyrocatechols, whose presence in the black liquor has been associated with an increase in corrosion of carbon steel, was also studied. Results from electrochemical tests point to the mechanisms by which the catechols may participate in the accelerated corrosion of carbon steels. This study demonstrates the role of organic constituents of the black liquor in determining its corrosivity. 相似文献
44.
Herman M. Montenegro 《Journal of the American Oil Chemists' Society》1985,62(2):259-261
Byproducts of processing coconut fruit include coconut water usable as a carbohydrate beverage or fermentable substance; the
husk, as a source of fibers, charcoal and chemicals; and the shell, usable primarily as a source of carbon. Coconut-shell
activated carbon is discussed in detail. This effective adsorbent has increasing applications in industrial and environmental
processes. 相似文献
45.
Morphology,mechanical performance,and nanoindentation behavior of injection molded PC/ABS‐MWCNT nanocomposites
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In this work, nanocomposites of polycarbonate/acrylonitrile‐butadiene‐styrene (PC/ABS) with various loads of multiwall carbon nanotubes (MWCNT) are investigated. Material is previously formed by masterbatch dilution approach and further processed by injection molding at various velocities. Microscopic characterization of nanocomposites morphology reveals stronger dependence of MWCNT dispersion on processing parameters at higher nanofiller load. Dispersion of carbon nanotubes at various distances from the injection gate is studied by Raman spectroscopy showing lower deviation at elevated injection velocity. Nanoindentation results that are in agreement with uniaxial tensile testing show a slight decrease of nanocomposites' mechanical performance at 3.0 wt % MWCNT in samples injected at reduced velocity. This is explained by the increase of agglomeration behavior at these conditions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42014. 相似文献
46.
L. Ferragut R. Montenegro G. Montero E. Rodríguez M.I. Asensio J.M. Escobar 《Journal of Wind Engineering & Industrial Aerodynamics》2010,98(10-11):548-558
In previous works, many authors have widely used mass consistent models for wind field simulation by the finite element method. On one hand, we have developed a 3-D mass consistent model by using tetrahedral meshes which are simultaneously adapted to complex orography and to terrain roughness length. In addition, we have included a local refinement strategy around several measurement or control points, significant contours, as for example shorelines, or numerical solution singularities. On the other hand, we have developed a 2.5-D model for simulating the wind velocity in a 3-D domain in terms of the terrain elevation, the surface temperature and the meteorological wind, which is consider as an averaged wind on vertical boundaries. Using the meteorological wind as datum, the 2.5-D model provides a 3-D local wind modified by topography and thermal gradients on the surface by solving only a 2-D optimal control problem where the boundary condition is the control. In this case, the finite element discretization consists on a triangular mesh adapted to the terrain topography and roughness length. In both models, the wind field adjusts to several wind speed measurements at several points in the 3-D domain and eventually to an average wind flux on the boundary.In this paper we introduce several advances in the 2.5-D and 3-D wind models and we compare their results on a region located in the Province of Lugo (Spain) with realistic data that have been provided by the company Desarrollos Eólicos S.A. (DESA). In order to obtain the best adjustment of models results to the measurements, the main parameters governing the models are estimated by using genetic algorithms with a parallel implementation. 相似文献
47.
Aflatoxin M1 in pasteurized and ultrapasteurized milk with different fat content in Mexico 总被引:1,自引:0,他引:1
High per capita milk consumption in Mexico indicated a strong need for documentation of aflatoxin M1 (AFM1) levels in milk. A survey of 580, 2-liter samples (n = 290), was conducted to quantify AFM1 using high-performance liquid chromatography, considering two maximum tolerance levels (0.05 and 0.5 microg/liter). We relate aflatoxin levels in the seven most consumed brands from different regions, with two processes (pasteurized and ultrapasteurized), different expiration dates, and different fat content: whole fat (28, 30, and 33 g), half-skimmed (10, 16, and 20 g), light (1, 2, and 4 g), and with vegetable oil. Pasteurization and ultrapasteurization did not diminish AFM1 contamination present at levels of 0 to 8.35 microg/liter in 40% of the milk samples at concentrations > or = 0.05 microg/liter and in 10% of the samples at > or = 0.5 microg/liter. Statistically significant relationships were AFM1 contamination with brand (P = 0.002 at the > or = 0.05 microg/liter level and P = 0.034 at the > or = 0.5 microg/ liter level) and higher AFM1 levels with mild or warm seasons of the year (P = 0.0003). Samples with greater fat content had slightly more probability (P = 0.067) of being contaminated by AFM1 at the > or = 0.5 microg/liter level. The milk with the lowest contamination of AFM1 was a brand imported as powder and rehydrated in Mexico. 相似文献
48.
Ana Karina Couto Campos Ângela Maria Soares Cardonha Liana Bacurau Galvão Pinheiro Neide Rocha Ferreira Paulo Roberto Medeiros de Azevedo Tânia Lúcia Montenegro Stamford 《Food Control》2009,20(9):807-810
The aim of this study was to assess the hygiene practices of food handlers in municipal schools of Natal, Brazil, where 27 public schools were evaluated, using a checklist and microbiological analysis of hands. It was found that 74.1% of the handlers did not receive periodic training, 51.9% did not undergo annual health examinations and 100% did not practice proper hand hygiene, a situation that reflected significantly (p < 0.05) in hand contamination, in which fecal coliforms were detected on 55.6% of the hands analyzed. It was concluded that the schools studied did not have appropriate hygienic conditions, suggesting the need for interventions that ensure the quality of school food served to the children. 相似文献
49.
50.
Diana Villanueva Alma-Delia Cuevas-Rasgado Omar Juárez Adolfo Guzmán-Arenas 《Expert systems with applications》2013,40(2):598-610
In natural language processing (NLP), disambiguation is the procedure used to solve name conflicts of polysemic concepts (different meanings); in fact, phrase disambiguation is a problem not totally solved in NLP. Several disambiguation types exist; for instance, noun disambiguation (bank is a word with several meanings) or when a word is both used as a noun and as a preposition. Work herein reported describes an algorithm and its implementation to disambiguate prepositions in Spanish phrases; some of them are: a {to} (Translation to English are in bold for explanation purposes; they give only one of the senses of the Spanish word, which usually have multiple meanings.), ante {before}, bajo {under}, cabe {fits}, desde {from}, contra {against}, en {in}, por {by}, según {according to}, sin {without}, entre {between}, so {under}, con {with}, hacia {towards}, sobre {about}, hasta {until}, de {of}, tras {after}, para {for}. This tool will be used in a text analyzer (being built) that converts a text document to its corresponding ontology representation, with the goal of allowing another program to use the information to answer non trivial questions (**). 相似文献