全文获取类型
收费全文 | 753篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 12篇 |
化学工业 | 130篇 |
金属工艺 | 6篇 |
机械仪表 | 17篇 |
建筑科学 | 16篇 |
矿业工程 | 1篇 |
能源动力 | 11篇 |
轻工业 | 50篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 58篇 |
一般工业技术 | 184篇 |
冶金工业 | 210篇 |
原子能技术 | 2篇 |
自动化技术 | 61篇 |
出版年
2021年 | 5篇 |
2019年 | 5篇 |
2017年 | 4篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 25篇 |
2012年 | 19篇 |
2011年 | 20篇 |
2010年 | 14篇 |
2009年 | 15篇 |
2008年 | 17篇 |
2007年 | 15篇 |
2006年 | 16篇 |
2005年 | 9篇 |
2004年 | 14篇 |
2003年 | 19篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 16篇 |
1999年 | 19篇 |
1998年 | 60篇 |
1997年 | 42篇 |
1996年 | 24篇 |
1995年 | 21篇 |
1994年 | 21篇 |
1993年 | 27篇 |
1992年 | 18篇 |
1991年 | 13篇 |
1990年 | 18篇 |
1989年 | 16篇 |
1988年 | 22篇 |
1987年 | 19篇 |
1986年 | 17篇 |
1985年 | 17篇 |
1984年 | 14篇 |
1983年 | 14篇 |
1982年 | 10篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 15篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1976年 | 13篇 |
1975年 | 8篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1970年 | 4篇 |
1969年 | 5篇 |
1967年 | 3篇 |
排序方式: 共有760条查询结果,搜索用时 15 毫秒
1.
The Wabash River Integrated Methanol and Power Production from Clean Coal Technologies (IMPPCCT) project is investigating an Early Entrance Coproduction Plant (EECP) concept to evaluate integrated electrical power generation and methanol production from coal and other carbonaceous feedstocks. Research, development and testing (RD&T) that is currently being conducted under the project is evaluating cost effective process systems for removing contaminants, particularly sulfur species, from the generated gas which contains mainly synthesis gas (syngas), CO2 and steam at concentrations acceptable for the methanol synthesis catalyst. The RD&T includes laboratory testing followed by bench-scale and field testing at the SG Solutions Gasification Plant located in West Terre Haute, Indiana. Actual synthesis gas produced by the plant was utilized at system pressure and temperature for bench-scale field testing. 相似文献
2.
TK Held ME Mielke M Chedid M Unger M Trautmann D Huhn AS Cross 《Canadian Metallurgical Quarterly》1998,91(7):2525-2535
Besides its well-established effects on granulocytopoiesis, granulocyte colony-stimulating factor (G-CSF) has been shown to have direct effects on the recruitment and bactericidal ability of neutrophils, resulting in improved survival of experimentally infected animals. We studied the effect of G-CSF on the course of experimental pneumonia induced by Klebsiella pneumoniae, an important gram-negative bacillary pulmonary pathogen. Using a highly reproducible murine model, we here show the paradoxical finding that mortality from infection was significantly increased when animals received G-CSF before induction of pneumonia. Administration of G-CSF promoted replication of bacteria in the liver and spleen, thus indicating an impairment rather than an enhancement of antibacterial mechanisms. By contrast, a monoclonal antibody against Klebsiella K2 capsule significantly reduced bacterial multiplication in the lung, liver, and spleen, and abrogated the increased mortality caused by G-CSF. In vitro studies showed a direct effect of G-CSF on K pneumoniae resulting in increased capsular polysaccharide (CPS) production. When bacteria were coincubated with therapeutically achievable concentrations of G-CSF, phagocytic uptake and killing by neutrophils was impaired. Western blot analysis showed three binding sites of G-CSF to K pneumoniae. Binding of 125I-G-CSF to K pneumoniae was displaced by an excess of unlabeled G-CSF, whereas an unrelated cytokine, interleukin-1alpha, did not compete with G-CSF binding to the bacteria. Thus, in this model, the direct effect of G-CSF on a bacterial virulence factor, CPS production, outweighed any beneficial effect of G-CSF on recruitment and stimulation of leukocytes. 相似文献
3.
J. Binner J. Wang B. Vaidhyanathan N. Joomun J. Kilner G. Dimitrakis T. E. Cross 《Journal of the American Ceramic Society》2007,90(9):2693-2697
A microwave/conventional hybrid furnace has been used to anneal virtually fully dense zinc oxide ceramics under pure conventional and a microwave/conventional hybrid heating regime with a view to obtaining evidence for the "microwave effect" during the resulting grain growth. In each case it was ensured that each sample within a series had an identical thermal history in terms of its temperature/time profile. The results showed that grain growth was enhanced during hybrid heating compared with pure conventional heating; the greatest enhancement, a factor of ∼3 increase in average grain size, was observed in the range 1100°–1150°C. The grain growth exponent decreased from 3 during conventional heating to 1.4 during hybrid heating in this temperature range, suggesting an acceleration of the diffusional processes involved. Temperature gradients within the samples were found to be too small to explain the results. This suggests that clear evidence has been found to support the existence of a genuine "microwave effect." 相似文献
4.
John H. Cross 《Journal of chemical ecology》1980,6(4):781-787
Chemicals (bp 270–490 °C/1 atm) evaporated from a controlled-release formulation dispenser were carried by an airflow to a collector packed with a polymeric adsorbent. After a set time, the chemicals were recovered by thermally desorbing them onto a gas-liquid chromatograpic column. They were then separated and quantified. The apparatus is described, and the requirements for its successful use are discussed. The soundness of the thermal desorption technique was confirmed by comparison with another technique: solvent elution from the collector. The advantages of the former technique are discussed.Mention of a commercial or proprietary product in this paper does not constitute an endorsement of that product by the USDA. 相似文献
5.
Apparatus and procedure for measuring release rates from formulations of lepidopteran semiochemicals
John H. Cross James H. Tumlinson Robert E. Heath Donald E. Burnett 《Journal of chemical ecology》1980,6(4):759-770
An apparatus was developed wherein a vacuum source was used to pull air across a controlled-release-formulation dispenser or a planchet containing a known quantity of a semiochemical and into a collector filled with a polymeric adsorbent. After a set time, the semiochemical was eluted with solvent and was quantified by gas-liquid chromatography (GLC). High percentages of known quantities of the lepidopteran semiochemicals (Z)-7-dodecen-l -ol acetate (Z7DDA), boiling point (bp) 275 ° C/1 atm, (Z)-9-tetradecen-1-ol formate (Z9TDF), bp 289 °C/1 atm, and (Z,Z)-3,13-octadecadien-1-ol acetate (ZZODDA), bp 490 °C/1 atm, were recovered. The semiochemicals did not oxidize and were recovered quantitatively from the adsorbent. The release rates of Z9TDF from a controlled-release dispenser were found to be directly proportional to the airflow rates. Release rate measurements on the Z9TDF dispensers were made for the purpose of estimating the method's precision. The method was shown to give internally consistent results by measurements on another Z9TDF formulation. The accuracy of the method is discussed.Mention of a commercial or proprietary product in this paper does not constitute an endorsement by the USDA. 相似文献
6.
Barium Metaplumbate Ceramic Electrodes for Ceramic Capacitors 总被引:2,自引:0,他引:2
Frank P. Skeele Robert E. Newnham Leslie E. Cross 《Journal of the American Ceramic Society》1988,71(5):263-C
A novel approach to reduce electrode costs in ceramic capacitors is presented. Barium metaplumbate (BaPbO3 ) was fired onto sintered commercial (Ba, Sr)TiO3 disk capacitors as external electrodes. Samples were compared to disk capacitors of the same composition with electrodes made of sputtered gold and air-dried silver. The ceramic electrode led to substantial changes in the insulation resistance and dc breakdown strengths, but other properties remained the same. The feasibility of using BaPbO3 electrodes strongly depends on chemical reactions between the electrode and dielectric. 相似文献
7.
8.
A fast and simple heuristic algorithm for polygonal approximation is presented. The algorithm is based on a mark and sweep technique. Results of computer implementation with various images are reported. 相似文献
9.
Twelve percent of high-oleic sunflower oil (HOSO) was incorporated into a swine diet to replace substantial amounts of saturated fatty acids (S) in pork by monounsaturated fatty acids (M). Pork loin chops (longissimus dorsi), cooked to 74°C, and eye of round roasts (semitendinosus), cooked to 77°C, from animals on the HOSO diet were 49% and 66%, respectively, higher in the M/S ratio as compared to their counterparts from animals on the control diet. Cooking had little effect on relative differences in the M/S ratio between HOSO and control samples. Cooking loss and sensory properties were not adversely affected by the changes in fatty acid composition. However, cooked chops and roasts from the HOSO group had lower thiobarbituric acid values during storage at 4°C. 相似文献
10.
George A. Rossett Jr. K. R. Udayakumar Michael J. Haun L. Eric Cross 《Journal of the American Ceramic Society》1990,73(11):3334-3338
A phenomenological free-energy function including the effects of elastic boundary conditions was presented and used to investigate the single-domain, single-crystal properties of the ferroelectric perovskite, PbTiO3 . In particular, the effects of tensile and compressive hydrostatic stress on the spontaneous polarization, Curie point, dielectric susceptibility, and piezoelectric property coefficients were examined. The calculated shift of the Curie point with hydrostatic stress, along with the entropy and enthalpy of the ferroelectric-paraelectric phase transition, was found to be in good agreement with experimental measurements. The isothermal variation of the relative dielectric susceptibility and piezoelectric coefficients with hydrostatic stress exhibited the expected behavior near the ferroelectric-paraelectric phase transition. 相似文献