全文获取类型
收费全文 | 4301篇 |
免费 | 64篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 45篇 |
综合类 | 2篇 |
化学工业 | 694篇 |
金属工艺 | 78篇 |
机械仪表 | 104篇 |
建筑科学 | 146篇 |
矿业工程 | 28篇 |
能源动力 | 76篇 |
轻工业 | 415篇 |
水利工程 | 41篇 |
石油天然气 | 9篇 |
无线电 | 344篇 |
一般工业技术 | 557篇 |
冶金工业 | 1307篇 |
原子能技术 | 49篇 |
自动化技术 | 476篇 |
出版年
2021年 | 35篇 |
2020年 | 22篇 |
2019年 | 29篇 |
2018年 | 45篇 |
2017年 | 43篇 |
2016年 | 38篇 |
2015年 | 35篇 |
2014年 | 45篇 |
2013年 | 213篇 |
2012年 | 113篇 |
2011年 | 138篇 |
2010年 | 134篇 |
2009年 | 118篇 |
2008年 | 162篇 |
2007年 | 159篇 |
2006年 | 134篇 |
2005年 | 152篇 |
2004年 | 118篇 |
2003年 | 130篇 |
2002年 | 104篇 |
2001年 | 79篇 |
2000年 | 85篇 |
1999年 | 110篇 |
1998年 | 269篇 |
1997年 | 156篇 |
1996年 | 142篇 |
1995年 | 105篇 |
1994年 | 88篇 |
1993年 | 87篇 |
1992年 | 61篇 |
1991年 | 47篇 |
1990年 | 58篇 |
1989年 | 61篇 |
1988年 | 67篇 |
1987年 | 63篇 |
1986年 | 48篇 |
1985年 | 53篇 |
1984年 | 51篇 |
1983年 | 55篇 |
1982年 | 59篇 |
1981年 | 44篇 |
1980年 | 32篇 |
1979年 | 41篇 |
1978年 | 46篇 |
1977年 | 48篇 |
1976年 | 74篇 |
1975年 | 40篇 |
1974年 | 34篇 |
1973年 | 50篇 |
1971年 | 27篇 |
排序方式: 共有4371条查询结果,搜索用时 0 毫秒
11.
K.W. Allen S.M. Smith W.C. Wake A.O. van Raalte 《International Journal of Adhesion and Adhesives》1985,5(1):23-32
The effect of cyclic stressing on the strength of single lap adhesive joints has been studied and a considerable reduction in strength observed when the maximum stress exceeds about 40% of the ultimate tensile strength, but whether or not a true endurance limit exists is not proven. Fallacies are shown in some of the techniques which have been proposed for studying the fatigue behaviour of adhesive joints. 相似文献
12.
A simple measurement method for the absolute Raman scattering cross-section of an optical fibre is presented. This method does not require a high power pump laser and it measures the fibre directly. It is also shown that the calculation of the cross-section depends on the fibre structure, such as its refractive index profile and the differential attenuation between the pump wavelength and Raman wavelength.<> 相似文献
13.
O'Driscoll Michael P.; Poelmans Steven; Spector Paul E.; Kalliath Thomas; Allen Tammy D.; Cooper Cary L.; Sanchez Juan I. 《Canadian Metallurgical Quarterly》2003,10(4):326
This study examined organizational family-responsive policies, perceptions of the organization as family supportive, and supervisor support as issues that may be salient to the experience of conflict between paid employment (work) and family roles. Data were collected from 355 managerial personnel in New Zealand. Although work-family conflict and psychological strain were strongly linked, the availability of organizational policies had no significant association with levels of conflict or strain, whereas policy usage was related only to work-to-family interference and not to family-to-work interference. On the other hand, perceptions of the organization as family supportive and supervisor support for work-family balance displayed significant relationships with key variables, highlighting the importance of these variables for interventions designed to ameliorate the negative impact of work-family conflict on managerial well-being. Implications for the effective implementation of family-responsive interventions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
14.
Allen Daniel N.; Strauss Gregory P.; Kemtes Karen A.; Goldstein Gerald 《Canadian Metallurgical Quarterly》2007,21(6):713
Hemispheric involvement in reasoning abilities has been debated for some time, and it remains unclear whether the right hemisphere's involvement in problem solving is modality specific or dependent on the type of spatial reasoning required. In the current study, 2 types of nonverbal reasoning abilities were examined, spatial reasoning and proportional reasoning, in 109 patients with cerebrovascular disease that was confined to either the right or the left hemisphere or was diffuse in nature. Results indicated that no lateralizing effects were present based on type of spatial reasoning. Findings are consistent with the suggestion that higher order cognitive processes involved in nonverbal abstraction and problem solving are not strongly lateralized to the right hemisphere but rather are more generally distributed throughout the cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
15.
The activity of rifabutin (LM 427) against Mycobacterium leprae was evaluated in armadillos inoculated earlier with human-derived M. leprae. Rifabutin was administered daily at a dose of 6 mg/kg body weight/day. The effect of rifabutin on M. leprae harvested from armadillos was determined by measuring the intracellular levels of ATP (an indicator of metabolic activity) of M. leprae and also their ability to multiply in the mouse footpads and in vitro in DH medium. Within 2 weeks of initiating the treatment, ATP levels declined to 21% of the original (pre-treatment level) and these M. leprae failed to multiply in the footpads of mice as well as in the in vitro culture system. This suggests that rifabutin was able to kill all M. leprae within 2 weeks. After 8 weeks the treatment was terminated and results showed that M. leprae from the treated armadillos remained non-viable in the mouse footpad system as well as in the in vitro system, indicating bactericidal action of rifabutin. The results suggest that rifabutin can be a substitute for rifampin in the leprosy multi-drug therapy regimen. 相似文献
16.
17.
Jue Donald; Meador Kimford J.; Zamrini Edward Y.; Allen Martha E.; Feldman Daniel S.; Loring David W. 《Canadian Metallurgical Quarterly》1992,6(4):331
Studied memory for visuospatial arrays in 28 male and 34 female healthy dextral adults (aged 20–90 yrs). 10 abstract figures were presented in each hemispace over a series of learning trials, and then delayed free recall of figure placement was obtained. Figures were misplaced significantly downward and leftward in both hemispaces. Both vertical and horizontal absolute error increased significanty with age, but no age effects on directional errors were observed. The increase in absolute error over age is consistent with decreased anterograde memory and visuospatial skills in the elderly. The directional errors are believed to result from an attentional shift toward proximal peripersonal space, in combination with attentional shifts from differential left vs right cerebral activation. Gender effects were also observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
18.
19.
This study reports on a multivariate analysis of the moving bed biofilm reactor (MBBR) wastewater treatment system at a Canadian pulp mill. The modelling approach involved a data overview by principal component analysis (PCA) followed by partial least squares (PLS) modelling with the objective of explaining and predicting changes in the BOD output of the reactor. Over two years of data with 87 process measurements were used to build the models. Variables were collected from the MBBR control scheme as well as upstream in the bleach plant and in digestion. To account for process dynamics, a variable lagging approach was used for variables with significant temporal correlations. It was found that wood type pulped at the mill was a significant variable governing reactor performance. Other important variables included flow parameters, faults in the temperature or pH control of the reactor, and some potential indirect indicators of biomass activity (residual nitrogen and pH out). The most predictive model was found to have an RMSEP value of 606 kgBOD/d, representing a 14.5% average error. This was a good fit, given the measurement error of the BOD test. Overall, the statistical approach was effective in describing and predicting MBBR treatment performance. 相似文献
20.
ABSTRACT: The effect of post-cooking holding-time on sensory assessment of low (89 g/kg) and high (218 g/kg) fat beefburgers was assessed. Burgers were served to panelists approximately 3 or 18 min after cooking. Fat content influenced fattiness, moistness/juiciness and overall appearance (P < 0.05), overall acceptability and overall texture (P< 0.01) and tenderness and crumbliness (p<0.001). Burgers with the higher fat content had higher scores. Holding-time influenced sensory overall appearance only with lower scores at extended holding times (P < 0.01). Treatment differences were small, mostly less than one sensory scale unit. Higher lightness and yellowness values were found for burgers with higher fat contents. 相似文献