全文获取类型
收费全文 | 257篇 |
免费 | 5篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 27篇 |
金属工艺 | 2篇 |
机械仪表 | 1篇 |
矿业工程 | 1篇 |
轻工业 | 16篇 |
无线电 | 15篇 |
一般工业技术 | 52篇 |
冶金工业 | 73篇 |
原子能技术 | 9篇 |
自动化技术 | 64篇 |
出版年
2019年 | 6篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2012年 | 6篇 |
2011年 | 14篇 |
2010年 | 6篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 7篇 |
2005年 | 11篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 2篇 |
1998年 | 11篇 |
1997年 | 5篇 |
1996年 | 16篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1974年 | 5篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1961年 | 1篇 |
1909年 | 2篇 |
1907年 | 2篇 |
1898年 | 2篇 |
排序方式: 共有262条查询结果,搜索用时 114 毫秒
1.
A. R. Gersborg O. Sigmund 《International journal for numerical methods in engineering》2011,87(9):822-843
This paper studies topology optimization of a coupled opto‐mechanical problem with the goal of finding the material layout which maximizes the optical modulation, i.e. the difference between the optical response for the mechanically deformed and undeformed configuration. The optimization is performed on a periodic cell and the periodic modeling of the optical and mechanical fields have been carried out using transverse electric Bloch waves and homogenization theory in a plane stress setting, respectively. Two coupling effects are included being the photoelastic effect and the geometric effect caused by the mechanical deformation. For the studied objective and material choice it is concluded that the photoelastic effect and the geometric effect counteract each other, which yields designs which are fundamentally different if the optimization takes only one effect into account. When both effects are active a compromise is found; however, a strong regularization is needed in order to achieve reasonable 0–1 designs with a clear physical interpretation. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
2.
Ole Sigmund 《Structural and Multidisciplinary Optimization》2011,43(5):589-596
Topology optimization is a highly developed tool for structural design and is by now being extensively used in mechanical,
automotive and aerospace industries throughout the world. Gradient-based topology optimization algorithms may efficiently
solve fine-resolution problems with thousands and up to millions of design variables using a few hundred (finite element)
function evaluations (and even less than 50 in some commercial codes). Nevertheless, non-gradient topology optimization approaches
that require orders of magnitude more function evaluations for extremely low resolution examples keep appearing in the literature.
This forum article discusses the practical and scientific relevance of publishing papers that use immense computational resources
for solving simple problems for which there already exist efficient solution techniques. 相似文献
3.
Burns Shaun Michael; Boyd Briana L.; Hill Justin; Hough Sigmund 《Canadian Metallurgical Quarterly》2010,55(1):81
Objective: To explore the relationship between employment status and community access, perceived community discrimination, social support from significant others, depressive symptoms, and gender-related variables for 83 men living with spinal cord injury. Study Design: Correlational research. Setting: Internet-based investigation employing spinal cord injury listservs. Main Outcome Measure: Participant employment status. Results: A forced-entry hierarchical logistic regression indicated that means of injury, community access and perceived community discrimination, social support from significant others, depressive symptoms, and men’s adherence to masculine norms for primacy of work, self-reliance, and emotional control significantly predicted employment status. Conclusions: Psychosocial variables such as community access, perceived discrimination, social support from significant others, depressive symptoms, and gender identity represent important and understudied predictors of employment status among men living with spinal cord injury. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Ethnicity and age issues: Attitudes affecting rehabilitation of individuals with spinal cord injury.
The individual with spinal cord injury, family, staff, and significant others bring attitudes regarding age and ethnicity into the rehabilitation team dynamic. Such preconceived attitudes may direct one's ability to be open to change and incorporate new information. The authors present 3 cases that highlight the bidirectional nature of bias challenges and the potential impact of bias issues on the hospital setting, staff, individual, family, and significant others. The bidirectional nature of bias challenges is illustrated with 2 cases of bias issues presented by individuals with spinal cord injury during hospitalization and with I case of bias impact on an individual health care provider. Interventions and strategies to maximize information sharing, education, and adjustment during hospitalization, discharge planning, and community living are discussed. Individuals may face increasing challenges in maximizing the derived benefit from both health care delivery and community services if personal bias plays a role in excluding qualified personnel from consideration. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Qi Zhang Brian Damit James Welch Hyoungjun Park Chang-Yu Wu Wolfgang Sigmund 《Journal of aerosol science》2010,41(9):880-888
Airborne biological agents, albeit intentionally released or naturally occurring, pose one of the biggest threats to public health and security. In this study, a microwave assisted nanofibrous air filtration system was developed to disinfect air containing airborne pathogens. Aerosolized E. coli vegetative cells and B. subtilis endospores, as benign surrogates of pathogens, were collected on nanofibrous filters and treated by microwave irradiation. Both static on-filter and dynamic in-flight tests were carried out. Results showed that E. coli cells were efficiently disinfected in both static and in-flight tests, whereas B. subtilis endospores were more resistant to this treatment. Microwave power level was found to be the major factor determining the effectiveness of disinfection. Both thermal and non-thermal effects of microwave irradiation contributed to the disinfection. Reducing flow velocity to decrease heat loss yielded higher disinfection efficiency. 相似文献
6.
7.
In a one-dimensional quantum mechanical model the phonon transmission between a solid and liquid He is calculated. It is shown how surface roughness changes the binding forces between the He atoms and the solid and therefore can lead to an increased transmission of low-energy phonons. In addition it turns out that the finite lifetimes of the He states also enhance the transmission probability.HILTI AG, FL-9494 Schaan, Liechtenstein. 相似文献
8.
Sigmund Hals 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1909,17(11):673-677
Ohne Zusammenfassung 相似文献
9.
Sigmund Merkel und Theodor Weigle 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1898,1(4):239-245
Ohne Zusammenfassung 相似文献
10.
Miguel M. Neves Ole Sigmund Martin P. Bendse 《International journal for numerical methods in engineering》2002,54(6):809-834
The problem of determining highly localized buckling modes in perfectly periodic cellular microstructures of infinite extent is addressed. A double scale asymptotic technique is applied to the linearized stability problem for a periodic structure built from linearly elastic microstructures. The obtained stability condition for the microscale level is then used to establish a comparative analysis between different material distributions in the base cell subjected to the same strain field at the macroscale level. The idea is illustrated by some two‐dimensional finite element examples and used to design materials with optimal elastic properties that are less prone to localized instability in the form of local buckling modes at the scale of the microstructure. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献