全文获取类型
收费全文 | 298篇 |
免费 | 10篇 |
专业分类
电工技术 | 3篇 |
综合类 | 4篇 |
化学工业 | 66篇 |
金属工艺 | 3篇 |
机械仪表 | 2篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 8篇 |
轻工业 | 22篇 |
石油天然气 | 6篇 |
无线电 | 21篇 |
一般工业技术 | 20篇 |
冶金工业 | 104篇 |
原子能技术 | 3篇 |
自动化技术 | 40篇 |
出版年
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 10篇 |
2017年 | 2篇 |
2016年 | 11篇 |
2015年 | 3篇 |
2014年 | 10篇 |
2013年 | 14篇 |
2012年 | 4篇 |
2011年 | 6篇 |
2010年 | 9篇 |
2009年 | 10篇 |
2008年 | 7篇 |
2007年 | 14篇 |
2006年 | 10篇 |
2005年 | 10篇 |
2004年 | 4篇 |
2003年 | 9篇 |
2002年 | 3篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 28篇 |
1997年 | 23篇 |
1996年 | 17篇 |
1995年 | 6篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1987年 | 5篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1977年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1966年 | 4篇 |
1965年 | 1篇 |
1963年 | 1篇 |
1961年 | 1篇 |
1955年 | 1篇 |
1944年 | 1篇 |
排序方式: 共有308条查询结果,搜索用时 203 毫秒
1.
2.
MB Heyman JM LaBerge KA Somberg P Rosenthal C Mudge EJ Ring JD Snyder 《Canadian Metallurgical Quarterly》1997,131(6):914-919
The transjugular intrahepatic portosystemic shunt procedure is an accepted treatment for adults with complications of portal hypertension. We performed a retrospective review of all pediatric TIPS placements performed at the University of California, San Francisco between 1990 and 1996. Twelve procedures were attempted in nine children, with a mean age (+/- SD) of 9.4 +/- 3.9 years (range, 5 to 15 years) and a mean weight of 31 +/- 18 kg (range, 16 to 70 kg). The indications for TIPS placement were portal hypertension complicated by chronic variceal hemorrhage not controlled with sclerotherapy (n = 7) and hypersplenism with thrombocytopenia (n = 2). TIPS placement was successfully completed initially in seven of nine (78%) patients. Unfavorable vascular anatomy was the cause of failure in two cases. The seven patients who underwent successful TIPS placement were followed up for an average of 136 days (range, 1 to 800 days); two still have patent shunts, three underwent liver transplantation, one had a splenorenal shunt after stenosis, and one died of underlying liver disease. Variceal bleeding was controlled in four of five patients who successfully underwent TIPS placement. Shunt occlusion occurred in four patients; patency was restored by transjugular shunt revision in three, and a splenorenal shunt was performed in one. 相似文献
3.
BD Shenstone A Mahmoud R Woodward D Elvins R Palmer EF Ring AK Bhalla 《Canadian Metallurgical Quarterly》1994,33(6):541-545
A prospective longitudinal study of patients with early RA was performed to examine the influence of disease duration, disease activity and physical activity on bone loss. Sixty-seven patients with non-steroid treated RA of less than 5 yr duration, including 16 patients with disease duration less than 6 months, had BMD measurements of the femoral neck and the lumbar spine over a 12-month period using dual energy X-ray absorptiometry. The BMD changes were compared with values from 72 control patients and were also correlated with serial measurements of disease activity (measured by the Stoke Index) and disability [measured by the Health Assessment Questionnaire (HAQ) score], at 3-monthly intervals over the 12-month period. No significant differences in BMD changes were found between RA patients and controls overall. Patients with disease duration of less than 6 months had significantly greater loss of BMD at the femoral neck (-3.9%, S.E.M. 1.5) than the remainder of the cohort (-0.2%, S.E.M. 0.7) (P = 0.02) and controls (-0.8%, S.E.M. 0.6). Lumbar spine BMD changes correlated with the initial Stoke Index (Rs-0.373, P = 0.01) but not mean Stoke Indices. There was no correlation of BMD changes with age or HAQ scores. These findings suggest that significant bone loss occurs within the first few months of disease in patients with RA. 相似文献
4.
5.
S.G. Ring 《Food Hydrocolloids》1987,1(5-6)
The aqueous solution behaviour of malto oligosaccharides, amylose and amylopectin is discussed. Experimental studies, using biophysical methods, on the aggregation behaviour of these compounds are reviewed. 相似文献
6.
7.
8.
9.
Honglin Chen Hong Yang Yevgenia Briker Craig Fairbridge Oladipo Omotoso Lianhui Ding Ying Zheng Zbigniew Ring 《Catalysis Today》2007,125(3-4):256-262
Pt supported on a carbon molecular sieve (Pt/CMS) was prepared by pyrolysis of polyfurfuryl alcohol containing pre-reduced Pt particles. The catalysts were characterized by hydrogen chemisorption, XRD, N2 adsorption/desorption and TEM. Hydrogen chemisorption showed that not all the Pt particles were exposed to H2 molecules. Oxidation treatment made Pt particles more accessible to H2. Catalyst activity was evaluated by hydrogenation of 1-hexene. Hydrogen spillover was demonstrated by diluting Pt/CMS with activated carbon or hydrogen type zeolite Y. The initial conversion of 1-hexene was increased from 86.5% to 98.5% and to 100% when Pt/CMS was diluted with activated carbon and hydrogen type zeolite, respectively. The high initial conversion was sustained for 6 h in the presence of diluents while the conversion decreased quickly for Pt/CMS alone. 相似文献
10.
E. W. Underhill J. G. Millar R. A. Ring J. W. Wong D. Barton M. Giblin 《Journal of chemical ecology》1987,13(6):1319-1330
A single sex pherormone component was isolated from abdominal tip extracts of female Bruce spanworm.Operophtera bruceata (Hulst). This was identified as (Z,Z,Z)-1,3,6,9-nonadecatetraene by capillary gas chromatography (GC), electroantennography, and mass spectrometry. In addition, hexane extracts of female abdominal tips from Bruce spanworm and the winter moth.O. brumata L., were analyzed by GC coupled to an electroantennographic detector (GC-EAD). The extracts ofO. bruceata andO. brumata females elicited only a single response, at the same retention time, from antennae of their conspecific and reciprocal males. In field tests conducted in Saskatchewan, traps baited with the synthetic tetraene captured Bruce spanworm males. In tests carried out on Vancouver Island, British Columbia, where the two species coexist, both Bruce spanworm and winter moth males were captured. The attractancy of lures containing the synthetic pheromone alone and in combination with several structurally related analogs was field tested at both locations. One of these, an isomer of the natural pheromone, (E,Z,Z)-1,3,6,9-nonadecatetraene, inhibited the capture of Bruce spanworm males but had no effect upon the number of winter moth males which were taken. Thus, populations of these two very similar species can be distinguished by employing traps baited with pheromone ± the inhibitor. Coneorifice Hara traps were found useful for field trapping males of both species.Issued as NRCC No. 26107 相似文献