全文获取类型
收费全文 | 242篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 20篇 |
金属工艺 | 3篇 |
机械仪表 | 4篇 |
建筑科学 | 9篇 |
能源动力 | 1篇 |
轻工业 | 28篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 11篇 |
一般工业技术 | 53篇 |
冶金工业 | 74篇 |
原子能技术 | 4篇 |
自动化技术 | 31篇 |
出版年
2022年 | 3篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 14篇 |
2012年 | 7篇 |
2011年 | 12篇 |
2010年 | 12篇 |
2009年 | 10篇 |
2008年 | 5篇 |
2007年 | 5篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 3篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 20篇 |
1997年 | 10篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1973年 | 3篇 |
1966年 | 1篇 |
1928年 | 2篇 |
排序方式: 共有245条查询结果,搜索用时 15 毫秒
21.
JL Mankowski DL Carter JP Spelman ML Nealen KR Maughan LM Kirstein PJ Didier RJ Adams M Murphey-Corb MC Zink 《Canadian Metallurgical Quarterly》1998,153(4):1123-1130
We investigated the effects of dietary factors on the pH and the ammonia emission from slurry of growing-finishing pigs. Sixteen male hybrid pigs (80 to 90 kg BW) were allotted to one of four diets based on barley-wheat, tapioca, barley-tapioca, and sugar beet pulp. Diets were formulated to have similar NE and CP contents and a similar lysine:NE ratio. Diets differed in nonstarch polysaccharide content (NSP) and dietary electrolyte balance (dEB). Urine and feces were daily collected quantitatively in metabolism cages and mixed as a slurry at the end of the collection period. After mixing, the pH and the ammonia emission from the slurry were measured daily in a laboratory setup for 7 d at 20 degrees C. The type of diet affected the pH of the slurry and the ammonia emission (P < .001). The pH of the slurry from pigs fed the sugar beet pulp-based diet was .8 unit lower and ammonia emission was 52 to 53% lower than that of the other three diets. The low dEB and high NPS sugar beet pulp-based diet increased the VFA concentration and reduced the pH and ammonia emission from the slurry. We conclude that dietary NSP and dEB influence the pH and ammonia emission from slurry of growing-finishing pigs. 相似文献
22.
This paper investigates the morphology changes that occur with the oxidation of a ti-tanium silicide—polysilicon system. These
changes were studied as a function of poly-silicon doping and silicide formation parameters. Emphasis was placed on transmission
electron microscopy studies of the samples by planar and cross sectional techniques. Various surface analysis methods have
also been used to characterize the films. This study helps to define the possible use and shortcomings of a self aligned titanium
silicide insulator. The results show that varying quality insulators result, dependent largely on the initial conditions of
the titanium silicide. After oxidation the Auger and TEM anal-ysis show that in all cases some form of silicon dioxide was
created, but typically a considerable amount of titanium oxide was also present. For instance, it was apparent that more titanium
oxide formed on the samples RTA’ed for 1 min at 700° C than the 5 min at 800° C and considerably more on the arsenic doped
sample than the boron doped. The silicide also had morphology changes as the result of the oxidation. There was a phase change
from the C49 to C54 phase for the 1 min at 700° C samples as would be expected at the time and temperature of the oxidation.
There also was a sig-nificant amount of agglomeration and epitaxial growth observed. Further work is re-quired to completely
characterize these phenomena. 相似文献
23.
Chun-Hao Tseng Fabian Hadipriono Josann Duane Patrick Maughan Earl W. Whitlatch 《Canadian Metallurgical Quarterly》2004,18(3):127-135
Crime has been plaguing parking garages in the United States. At The Ohio State University, (OSU) crime on campus, in general, has decreased in recent years; however, crime in OSU parking garages has remained stable in spite of campus-wide efforts to reduce crime. When assessing and evaluating parking garages, occupants employ experience-based judgment that is subjective and imprecise, yet extremely useful. When designers employ the principles of crime prevention through environmental design, they also use subjective variables. An approach that captures the imprecise information in noncrisp expressions reflecting subjective and experience-based variables is the fuzzy logic concept. This concept allows the use of mathematical operations to manipulate and operate on imprecise information or knowledge. Variables such as garage illumination and wall height were collected, fuzzified, and treated as the knowledge base of a model presented in this paper. In addition, numerous experience-based implication rules were developed and employed to evaluate subjective variables. A computer program was developed to illustrate implementation of the model. 相似文献
24.
The authors investigated whether memory for object locations in pictures could be exploited to address known difficulties of designing query languages for picture databases. M. W. Lansdale's (1998) model of location memory was adapted to 4 experiments observing memory for everyday pictures. These experiments showed that location memory is quantified by 2 parameters: a probability that memory is available and a measure of its precision. Availability is determined by controlled attentional processes, whereas precision is mostly governed by picture composition beyond the viewer's control. Additionally, participants' confidence judgments were good predictors of availability but were insensitive to precision. This research suggests that databases using location memory are feasible. The implications of these findings for database design and for further research and development are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
25.
26.
Okubo S. Dunstan S. Morrison G. Nilsson M. Radha H. Skran D.L. Thom G. 《Selected Areas in Communications, IEEE Journal on》1997,15(6):965-982
This paper presents the ITU-T Study Group 15 development of H-series Recommendations that allow interworking between different audiovisual communication terminals manufactured by different equipment providers. The paper focuses on H.310 and H.321 systems for broad-band ATM environments and H.322 and H.323 systems for LAN environments where the quality of service may or may not be guaranteed. The paper first lists the Recommendations developed by the ITU-T for audiovisual communication systems and the network environments in which they may be used. It then describes the design philosophy, the network specific characteristics, and hardware trials for each system. Then it describes the communication control protocol defined in H.245 which is used commonly by different audiovisual communication systems. Finally, the paper discusses interworking scenarios for communication between the different types of terminal on different networks 相似文献
27.
CH Chen M Nakayama E Nevo BJ Fetics WL Maughan DA Kass 《Canadian Metallurgical Quarterly》1998,32(5):1221-1227
OBJECTIVES: We tested the hypothesis that age-related arterial stiffening is matched by ventricular systolic stiffening, and that both enhance systolic pressure sensitivity to altered cardiac preload. BACKGROUND: Arterial rigidity with age likely enhances blood pressure sensitivity to ventricular filling volume shifts. Tandem increases in ventricular systolic stiffness may also occur and could potentially enhance this sensitivity. METHODS: Invasive left ventricular pressure-volume relations were measured by conductance catheter in 57 adults aged 19 to 93 years. Patients had normal heart function and no cardiac hypertrophy and were referred for catheterization to evaluate chest pain. Twenty-eight subjects had normal coronary angiography and hemodynamics, and the remaining had either systolic hypertension or coronary artery disease without infarction. Data recorded at rest and during transient preload reduction by inferior vena caval obstruction yielded systolic and diastolic left ventricular chamber and effective arterial stiffness and pulse pressure. RESULTS: Left ventricular volumes, ejection fraction and heart rate were unaltered by age, whereas vascular load and stiffening increased (p < 0.008). Arterial stiffening (Ea) was matched by increased ventricular systolic stiffness (Ees): Ees=0.91 x Ea + 0.53, (r=0.50, p < 0.0001), maintaining arterial-heart interaction (Ea/Ees ratio) age-independent. Ventricular systolic and diastolic stiffnesses correlated (r=0.51, p < 0.0001) and increased with age (p < 0.03). Both ventricular and vascular stiffening significantly increased systolic pressure sensitivity to cardiac preload (p < 0.006). CONCLUSIONS: Arterial stiffening with age is matched by ventricular systolic stiffening even without hypertrophy. The two effects contribute to elevating systolic pressure sensitivity to altered chamber filling. In addition to recognized baroreflex and autonomic dysfunction with age, combined stiffening could further enhance pressure lability with diuretics and postural shifts in the elderly. 相似文献
28.
29.
30.
J Mayet M Shahi NR Poulter PS Sever RA Foale SA Thom 《Canadian Metallurgical Quarterly》1997,11(9):593-594
In order to investigate the spectrum of geometry in our patient population, 63 untreated hypertensives underwent two-dimensional echocardiography. Left ventricular (LV) mass index and relative wall thickness, a measure of wall thickness in relation to cavity size, were calculated from the M-mode strip. In addition, to assess the sphericity of the left ventricle the ratio of LV minor to major hemiaxis was calculated. The subjects comprised 41 men (17 Caucasian, 22 Afro-Caribbean and two Oriental), and 21 women (five Caucasian, 12 Afro-Caribbean and two Oriental). Concentric hypertrophy was present in 46% of subjects, concentric remodelling in 32% of subjects, eccentric hypertrophy in only 6% of subjects and a normal left ventricular shape in 16% of subjects. The degree of sphericity of the left ventricle was similar among the four groups, suggesting that it does not change in uncomplicated hypertension. In contrast to the previously published combined series from Sassari and New York we had a low proportion of patients with either eccentric hypertrophy or normal left ventricular geometry. This is probably due to the high proportion of Afro-Caribbean subjects in our clinic population who are more likely to have left ventricular hypertrophy. 相似文献