全文获取类型
收费全文 | 596篇 |
免费 | 44篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 215篇 |
金属工艺 | 3篇 |
机械仪表 | 22篇 |
建筑科学 | 22篇 |
矿业工程 | 1篇 |
能源动力 | 28篇 |
轻工业 | 142篇 |
水利工程 | 3篇 |
石油天然气 | 5篇 |
无线电 | 17篇 |
一般工业技术 | 80篇 |
冶金工业 | 41篇 |
原子能技术 | 3篇 |
自动化技术 | 56篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 22篇 |
2021年 | 36篇 |
2020年 | 21篇 |
2019年 | 26篇 |
2018年 | 19篇 |
2017年 | 22篇 |
2016年 | 23篇 |
2015年 | 13篇 |
2014年 | 35篇 |
2013年 | 49篇 |
2012年 | 34篇 |
2011年 | 42篇 |
2010年 | 23篇 |
2009年 | 31篇 |
2008年 | 36篇 |
2007年 | 32篇 |
2006年 | 31篇 |
2005年 | 17篇 |
2004年 | 15篇 |
2003年 | 11篇 |
2002年 | 12篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 7篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有640条查询结果,搜索用时 593 毫秒
51.
Luciana C. Costa Ailton S. Gomes Fernanda M.B. Coutinho Viviane G. Teixeira 《Reactive and Functional Polymers》2010,70(10):738-746
Chelating resins for mercury adsorption were prepared by grafting polyacrylamide chains onto styrene–divinylbenzene (Sty–DVB) copolymers by applying gamma radiation. Sty–DVB copolymers were synthesized by aqueous suspension polymerization employing different synthesis conditions. The copolymers were characterized by apparent density, surface area, pore size distribution and swelling capacity. The copolymers were irradiated using a 60Co-γ source at room temperature in the presence of acrylamide solution in methanol. The grafting reaction was evaluated with the aid of elemental analysis, FTIR and thermogravimetric analysis (TGA). Hg(II) uptake measurements were carried out in batch experiments. The results showed that these resins can be successfully used for Hg(II) adsorption at ppm levels. The porosity degree of the copolymers influences the grafting yield as well as the Hg(II) complexation capacity of the chelating resins. 相似文献
52.
Ian J. Dagley Luciana Montelli Robert P. Parker Veronica M. Silva 《Journal of Energetic Materials》2013,31(2-3):127-149
Abstract The viability of preparing booster compositions from RDX and commercially available aqueous polyurethane, acrylic and ethylene-vinyl acetate dispersions has been assessed. These dispersions were coagulated in hot aqueous slurries of RDX by electrolyte addition and the use of thermal coagulation aids. When polymer coating of the RDX crystals occurred the precipitated polymer particles were deposited across the surfaces of the crystals. These coatings were often porous; however when softer polymers were used, coalescence occurred and more uniform coatings were obtained. Compositions containing these softer polymers were less sensitive to initiation by shock and impact. The flow properties of these compositions were usually improved by applying an additional coating of zinc stearate. The impact sensitiveness, shock sensitivity and cookoff behaviour of a number of candidate booster compositions have been assessed and suitable compositions have been identified. 相似文献
53.
The work shows how natural illuminance values inside buildings depend on the calculation method of the sky luminance distribution implemented in the computer code which, for a room of fixed geometry and characteristics, transforms the outdoor meteorological data into indoor illuminance data. 相似文献
54.
55.
Davinson Mariano da Silva Luciana Reyes Pires Kassab Massimo Olivero Thiago B.N. Lemos Douglas V. da Silva A.S.L. Gomes 《Optical Materials》2011,33(12):1902-1906
The authors report the fabrication and characterization of active waveguides in GeO2–PbO–Ga2O3 glass samples doped with Er3+, written with a femtosecond laser delivering pulses of 150 fs duration at 1 kHz repetition rate. Permanent refractive index change was obtained and waveguides were formed under different laser pulse energies and scan velocities. The passive and active optical properties of the waveguides were investigated. The minimum value of propagation loss was of 4.8 dB/cm. Optical amplification at 1.5 μm under 980 nm excitation was observed showing a maximal internal gain of 2.7 dB/cm. 相似文献
56.
57.
Luciana da Cunha Fernanda M. B. Coutinho Viviane G. Teixeira Edgar F. O. de Jesus Ailton S. Gomes 《Polymer Bulletin》2008,61(3):319-330
Polyacrylamide chains were grafted onto styrene-divinylbenzene (S-DVB) copolymer beads using gamma
radiation from a 60Co source by applying the simultaneous method. S-DVB macroporous
copolymer was synthesized by aqueous suspension polymerization and characterized by determining apparent
density, surface area, pore volume distribution and water uptake. Optical and electron microscopies
were used in order to observe the copolymer morphology. The effect of parameters such as monomers concentration,
irradiation dose and presence of inhibitor (Mohr’s salt) on grafting reaction was studied. The grafting
reaction was evaluated with the aid of elemental analysis, FTIR, HR-MAS NMR spectrometry, thermogravimetry
(TG) and electron microscopy. Grafting yield (evaluated by nitrogen content) increased with acrylamide
concentration and irradiation dose increasing. However, above determined values of those parameters
it is observed a tendency of decreasing on the grafting yield. The presence of Mohr’s salt inhibited
the production of homopolymer as well as the progress of the grafting reaction. 相似文献
58.
Hooper Catalina J.; Luciana Monica; Conklin Heather M.; Yarger Rebecca S. 《Canadian Metallurgical Quarterly》2004,40(6):1148
Healthy adolescents (79 girls, 66 boys), ages 9-17, completed the Iowa Gambling Task (IGT; A. Bechara, A. R. Damasio, H. Damasio, & S. W. Anderson, 1994) as well as working memory (digit span) and behavioral inhibition (go/no-go) tasks. Cross-sectional age-related changes were seen on all 3 tasks. Gender differences were seen in IGT deck preference and attentional variables (i.e., go/no-go hit rate and forward digit span). After age, gender, and general intellectual abilities were controlled for, IGT performance was not predicted by working memory or behavioral inhibition scores. Findings suggest that the ventromedial prefrontal cortex or its connections are functionally maturing during adolescence in a manner that can be distinguished from maturation of other prefrontal regions. Development of these functions may continue into young adulthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
59.
Thompson M.G. Marinelli C. Tan K.T. Williams K.A. Penty R.V. White I.H. Kaiander I.N. Sellin R.L. Bimberg D. Kang D.-J. Blamire M.G. Visinka F. Jochum S. Hansmann S. 《Electronics letters》2003,39(15):1121-1122
Hybrid modelocking of monolithic quantum dot lasers is reported for the first time. A marked performance improvement over passive modelocking is demonstrated. Both hybrid and passive modelocking at /spl sim/10 GHz are achieved for the first time in quantum dot lasers. 相似文献
60.
Luciana Porter Bolland Allan P. Drew Carmen Vergara-Tenorio 《Landscape and urban planning》2006,74(3-4):223-241
An analysis of the natural resource management system was carried out for the ejido X-kanha located in the northern part of the Calakmul Biosphere Reserve in Campeche, Mexico. Through field research using participatory rural appraisal (PRA), the activities carried out by different user groups were identified. Gender roles as well as age roles were analyzed. Results show that each family depends upon the diversification of productive activities in order to meet economic needs. Diversification of activities is carried out in both space and time, making use of different ecosystems during varied seasons throughout the year. Women's activities correspond to housekeeping and house administration; they take care of home gardens and are responsible for water collection and wood gathering. Men carry out the activities of working in the milpa, cattle raising, honey production, chicle collection, and wood felling.A series of PRA activities carried out with the people of X-Kanha led to the identification of limitations to more optimal uses of natural resources. The characterization of limitations and associated alternatives is used to provide a guideline to aid the efforts of NGOs and other organizations interested in the conservation of natural resources, and for the well-being of the local population. 相似文献