全文获取类型
收费全文 | 134篇 |
免费 | 4篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 21篇 |
机械仪表 | 1篇 |
建筑科学 | 6篇 |
能源动力 | 1篇 |
轻工业 | 6篇 |
水利工程 | 2篇 |
无线电 | 23篇 |
一般工业技术 | 12篇 |
冶金工业 | 50篇 |
原子能技术 | 2篇 |
自动化技术 | 13篇 |
出版年
2018年 | 2篇 |
2017年 | 2篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 5篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 8篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 13篇 |
1997年 | 8篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 5篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1964年 | 1篇 |
1941年 | 2篇 |
1939年 | 1篇 |
1938年 | 1篇 |
1937年 | 1篇 |
1936年 | 1篇 |
1935年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有138条查询结果,搜索用时 0 毫秒
1.
DH Kang CL Coe DO McCarthy NN Jarjour EA Kelly RR Rodriguez WW Busse 《Canadian Metallurgical Quarterly》1997,17(8):481-487
T cell cytokines play an important role in mediating airway inflammation in asthma. The predominance of a Th2 cytokine profile, particularly interleukin (IL)-4 and IL-5, is associated with the pathogenesis and course of asthma. The aim of this study was to test the hypothesis that a stressful life event alters the pattern of cytokine release in asthmatic individuals. Thirteen healthy controls and 21 asthmatic adolescents gave blood samples three times over a semester: midsemester, during the week of final examinations, and 2-3 weeks after examinations. Interferon-gamma (IFN-gamma), IL-2, IL-4, and IL-5 were measured from supernatants of cells stimulated with PHA/PMA for 24 h. Cells from asthmatic subjects released significantly more IL-5 during the examination and postexamination periods, whereas cells from healthy controls released significantly more IL-2 during the midsemester and examination periods, thereby indicating a bias for a Th2-like pattern in asthmatics and a Th1-like pattern in healthy controls. IL-4 and IL-5 production showed a marked decrease during and after examinations in healthy controls, whereas this decline was absent in asthmatics. The ratios of IFN-gamma:IL-4 and IFN-gamma:IL-5 also revealed significant changes in the profile of cytokine release across the semester. These results indicate differential cytokine responses in asthmatics that may become pronounced during periods of cellular activation. 相似文献
2.
3.
Garrett BC Dixon DA Camaioni DM Chipman DM Johnson MA Jonah CD Kimmel GA Miller JH Rescigno TN Rossky PJ Xantheas SS Colson SD Laufer AH Ray D Barbara PF Bartels DM Becker KH Bowen KH Bradforth SE Carmichael I Coe JV Corrales LR Cowin JP Dupuis M Eisenthal KB Franz JA Gutowski MS Jordan KD Kay BD Laverne JA Lymar SV Madey TE McCurdy CW Meisel D Mukamel S Nilsson AR Orlando TM Petrik NG Pimblott SM Rustad JR Schenter GK Singer SJ Tokmakoff A Wang LS Wettig C Zwier TS 《Chemical reviews》2005,105(1):355-390
4.
Two high‐head dams on the Elwha River in Washington State (USA) have changed the migratory patterns of resident and anadromous fish, limiting Pacific salmon to the lower 7.9 km of a river that historically supported large Pacific salmon runs. To document the effects of the dams prior to their removal, we measured carbon and nitrogen stable isotope ratios of primary producers, benthic macroinvertebrates, and fish, and water chemistry above, between and below the dams. We found that δ15N was significantly higher in fish, stoneflies, black flies, periphyton and macroalgae where salmon still have access. Fish and chloroperlid stoneflies were enriched in δ13C, but the values were more variable than in δ15N. For some taxa, there were also differences between the two river sections that lack salmon, suggesting that factors other than marine‐derived nutrients are structuring longitudinal isotopic profiles. Consistent with trophic theory, macroalgae had the lowest δ15N, followed by periphyton, macroinvertebrates and fish, with a range of 6.9, 6.2 and 7.7‰ below, between, and above the dams, respectively. Water chemistry analyses confirmed earlier reports that the river is oligotrophic. Phosphorous levels in the Elwha were lower than those found in other regional rivers, with significant differences among regulated, unregulated and reference sections. The removal of these dams, among the largest of such projects ever attempted, is expected to facilitate the return of salmon and their marine‐derived nutrients (MDN) throughout the watershed, possibly altering the food web structure, nutrient levels and stable isotope values that we documented. Published in 2010 by John Wiley & Sons, Ltd. 相似文献
5.
P. I. Williams M. W. Gallagher T. W. Choularton H. Coe K. N. Bower G. McFiggans 《Aerosol science and technology》2013,47(2):120-126
Wintertime measurements of atmospheric aerosol over the size range 3-500 nm made approximately 30 m above street level in central Manchester are reported. These are compared with measurements of trace gases. It is found that secondary accumulation mode particles follow closely the values of NOx in the atmosphere and are closely related to vehicle activity, reaching a maximum at about 9 am. New particle formation close to the observation point is closely related to SO2 concentrations, predominately during daylight hours, and is a maximum around mid-day but persists after dark. The concentrations of fine and Aitken mode particles were much higher than in nearby rural areas, but the concentration of particles in the size range 200-500 nm were similar at the urban and rural sites. In addition, measurements of ammonia, a gas often important in nucleation kinetics, revealed concentrations up to 17 ppb in Manchester. 相似文献
6.
To test the hypothesis that factors of racial differences may mediate counselor–client interactions in terms of the counselor's attending and expressive response style and the delivery and type appropriateness of responses, 60 graduate level Black and White counselor trainees were asked to counsel both Black and White clients. As hypothesized, Ss' delivery scores and the type appropriateness of responses were significantly better under conditions of racial similarity with the clients. Both Black and White Ss were rated as being more expressive than attending in their response patterns toward Black clients. Findings have implications for counselor–client relationships and professional training programs for psychological counseling in multiracial settings. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
8.
Cerebrospinal fluid (CSF) samples were collected from monkeys infected with SIVmac251 (SIV) or HIV-1/SIVmac chimeric viruses (SHIV(HXBc2) and SHIV(89.6P)) to investigate quinolinic acid (QUIN) levels in the intrathecal compartment. CSF levels of QUIN were elevated in the SIV-infected monkeys, especially in animals with end-stage disease, and in those infected with pathogenic SHIV(89.6P), but not after infection with the nonpathogenic construct SHIV(HXBc2). QUIN elevations occurred in association with reduced CD4+ and increased CD8+ lymphocytes, cellular alterations that were more pronounced in CSF than in the blood. These findings support the view that the intrathecal compartment provides a unique window on viral infection, and are in keeping with the a priori prediction that QUIN increases primarily in response to more pathogenic viral strains. 相似文献
9.
Shyu C.-R. Gree J.M. Lun D.P.K. Kazic T. Schaeffer M. Coe E. 《Signal Processing Magazine, IEEE》2007,24(3):115-118
This work will allow bio-informaticians to analyze the ever-increasing gene sequence data, discover valuable knowledge in maize biology and related plant; development, and understand subtle variations among different phenotypes. Furthermore, successful measuring of visual phenotypes will advance plant research by finding the genes and/or environmental factors that cause a given visual phenotype. In what follows, the field of plant genetics is introduced (particularly quantitative trait loci and disease scoring) to the signal processing community, discuss the challenges involved, and present an image analysis system for precisely quantifying and mapping immeasurable phenotypes in maize 相似文献
10.
BA Shore RL Babbitt KE Williams DA Coe A Snyder 《Canadian Metallurgical Quarterly》1998,31(4):621-633
Children with feeding disorders often display severe food selectivity. For many of these children, consuming highly textured foods may be aversive or potentially dangerous because of frequent gagging. The purpose of this study was to demonstrate the efficacy of texture fading in the treatment of food selectivity displayed by 4 children. Treatment involved the gradual addition of higher textures based on the results of periodic probes. In addition, food acceptance and swallowing were reinforced, while food refusal and food expulsion were placed on extinction. Results showed that all participants successfully advanced to consumption of age-appropriate texture and volume. The results suggest that texture fading with intermittent probes at higher textures may be an effective method for the treatment of food selectivity by texture. 相似文献