全文获取类型
收费全文 | 5833篇 |
免费 | 80篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 38篇 |
综合类 | 1篇 |
化学工业 | 620篇 |
金属工艺 | 125篇 |
机械仪表 | 101篇 |
建筑科学 | 117篇 |
矿业工程 | 5篇 |
能源动力 | 72篇 |
轻工业 | 283篇 |
水利工程 | 19篇 |
石油天然气 | 8篇 |
无线电 | 540篇 |
一般工业技术 | 699篇 |
冶金工业 | 2948篇 |
原子能技术 | 33篇 |
自动化技术 | 312篇 |
出版年
2021年 | 34篇 |
2019年 | 26篇 |
2018年 | 38篇 |
2017年 | 28篇 |
2016年 | 39篇 |
2015年 | 30篇 |
2014年 | 52篇 |
2013年 | 147篇 |
2012年 | 90篇 |
2011年 | 95篇 |
2010年 | 99篇 |
2009年 | 116篇 |
2008年 | 121篇 |
2007年 | 115篇 |
2006年 | 101篇 |
2005年 | 101篇 |
2004年 | 86篇 |
2003年 | 101篇 |
2002年 | 75篇 |
2001年 | 91篇 |
2000年 | 114篇 |
1999年 | 163篇 |
1998年 | 919篇 |
1997年 | 532篇 |
1996年 | 360篇 |
1995年 | 217篇 |
1994年 | 181篇 |
1993年 | 203篇 |
1992年 | 66篇 |
1991年 | 92篇 |
1990年 | 101篇 |
1989年 | 97篇 |
1988年 | 69篇 |
1987年 | 82篇 |
1986年 | 64篇 |
1985年 | 86篇 |
1984年 | 69篇 |
1983年 | 65篇 |
1982年 | 49篇 |
1981年 | 68篇 |
1980年 | 63篇 |
1979年 | 43篇 |
1978年 | 31篇 |
1977年 | 104篇 |
1976年 | 158篇 |
1975年 | 40篇 |
1974年 | 36篇 |
1973年 | 45篇 |
1972年 | 23篇 |
1970年 | 24篇 |
排序方式: 共有5921条查询结果,搜索用时 15 毫秒
271.
Steam oxidation of Zircaloy-2 produces tensile extension; at a given temperature the strain increases parabolically with time. Oxygen dissolution in Zircaloy-2 during oxidation stabilises the α-phase and causes lattice dilatation. These two observations are used to develop a model of the oxidation-induced deformation behaviour of the stabilised α-layer and hence to calculate the stress distribution across the layer. 相似文献
272.
This paper describes the application of a survival analysis model and a Classification and Regression Trees (CART) model to a data set comprising times to growth of a yeast cocktail inoculated into media simulating a fruit-based or alcoholic food or drink, and covering over 900 combinations of five environmental factors (alcohol, pH, sucrose, sorbate and temperature). Growth was determined as either the time to growth within a 150-day time period or as no-growth after 150 days. Models were developed which could either predict the likelihood of growth occurring within the 150 day period, or the time to grow, either in days or in one of three categories chosen to represent a rapid (1-14 days), medium (15-30 days) or slow (31-150 days) growth response. Growth was observed in 29% of the experimental conditions and demonstrated that the yeasts used were able to grow under extreme environmental conditions, for example at a pH value of 2.1, a temperature of 2 degrees C, a sucrose concentration of 55% (w/w) or an alcohol concentration of 12% (w/v). Generally, both models provided a reasonable fit to the data, and successfully predicted the growth class in 84% of cases. Direct comparisons of the models were made to determine the more suitable for predicting the growth of yeasts in food systems. The survival analysis model was preferred for this data set because it was more fail-safe than the CART model. In food validation studies, the survival model generally gave reliable predictions of time to growth in a range of 23 different food and drink products and is considered to be a reliable model to predict the likelihood and speed of yeast spoilage for a range of fruit-based or alcoholic food or drinks. 相似文献
273.
274.
Assessing blood flow control through a bootstrap method 总被引:2,自引:0,他引:2
Simpson DM Panerai RB Ramos EG Lopes JM Marinatto MN Nadal J Evans DH 《IEEE transactions on bio-medical engineering》2004,51(7):1284-1286
In order to assess blood flow control, the relationship between blood pressure and blood flow can be modeled by linear filters. We present a bootstrap method, which allows the statistical analysis of an index of blood flow control that is obtained from constrained system identification using an established set of pre-defined filters. 相似文献
275.
A diverse set of 53 cyclooxygenase-2 (COX-2) inhibitors which were aligned in two different ways were subjected to CoMFA analysis. The first method of alignment of the molecules was based on the binding information sourced from the crystallographic study, from which CoMFA Model 1 was derived. The second mode of alignment was generated by docking the inhibitors in the binding pocket using the DOCK and AFFINITY suite of programs; this gave a second model. The CoMFA Model 2 was slightly better than Model 1 in terms of the statistical parameters r(2) and q(2). The two models could predict very well the activity of a test set of diverse molecules, with a predictive r(2) of 0.593 and 0.768, respectively. Besides the QSAR results, the docking studies give a deep insight into the H-bonding interactions between the inhibitors and residues in the active site of the enzyme, which can be exploited in designing better inhibitors. Useful ideas on activity improvement could be gleaned from these models. 相似文献
276.
Lisa Stead Petar Goulev Caroline Evans Ebrahim Mamdani 《Personal and Ubiquitous Computing》2004,8(3-4):282-290
Since the industrial revolution, fashion and technology have been linked through the textile and manufacturing industries, a relationship that has propelled technical innovation and aesthetic and social change. Today, a new alliance is emerging through the integration of electronic technology and smart materials on the body. This study addresses the integration of technology with clothing from a fashion perspective, and examines its expressive and interactive potential. It proposes the concept of The Emotional Wardrobe: clothing that represents and stimulates emotional response through the interface of technology. It asks if fashion can offer a more personal and provocative definition of self, which actively involves the wearer in a mutable aesthetic identity. A multi-disciplinary framework combines fashion, material science and the real-time, affective computing platform, called AffectiveWare. By merging technology and fashion, The Emotional Wardrobe becomes a poetic interface, shifting emphasis from human–computer interaction to computer-aided, human–human communication. 相似文献
277.
A binary 50% mixture of soft spheres is studied via nonequilibrium molecular dynamics, and the equilibrium and nonequilibrium radial distribution functions for a nonconformal mixture with a mass ratio of 10 and a size ratio of about 2 are examined. This model system is related to the real methane/decane mixture, and it is shown that apparently anomalous properties of this mixture, especially the viscosity, could perhaps be understood in terms of the local or ambient mole fraction. In addition, the postulates of the Van der Waals one fluid conformal solution theory are discussed, and a mixing rule for the mass is derived. 相似文献
278.
Pettinati Helen M.; Evans Frederick J.; Orne Emily C.; Orne Martin T. 《Canadian Metallurgical Quarterly》1981,90(4):345
Evaluated memory for successful and unsuccessful responses to hypnotic suggestions in partially amnesic Ss and in those Ss with normal forgetting. Two analyses (278 undergraduates) demonstrated that highly hypnotizable Ss experiencing partial posthypnotic amnesia tended to show no selective recall for their successes or failures during amnesia, whereas the remainder of the Ss showed definite selective recall of hypnotic success posthypnotically. These findings support F. J. Evans and J. F. Kihlstrom's (see record 1974-06307-001) hypothesis that posthypnotic amnesia involves a disruption of memory organization and suggest that the phenomenon may be mediated by a restriction in the use of normally employed retrieval cues. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
279.
Jejunal villous changes associated with farmer's lung 总被引:1,自引:0,他引:1
TJ Robinson SD Nelson M Haire D Middleton SA McMillan JP Evans 《Canadian Metallurgical Quarterly》1981,57(673):697-701
280.
Given the first few failures times of a sample of components whose lifetimes follow a Weibull distribution with both scale and shape parameters unknown, a Bayesian approach is used to derive prediction bounds for the failure times of the remaining components in the sample. Iterative procedures involving considerable computation are necessary for calculating prediction bounds, but some simplification is possible on restricting the shape parameter to a finite number of values. A numerical example illustrates the procedures. 相似文献