全文获取类型
收费全文 | 81篇 |
免费 | 4篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 7篇 |
机械仪表 | 1篇 |
建筑科学 | 15篇 |
能源动力 | 1篇 |
轻工业 | 14篇 |
无线电 | 7篇 |
一般工业技术 | 14篇 |
冶金工业 | 14篇 |
自动化技术 | 11篇 |
出版年
2021年 | 1篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 2篇 |
2012年 | 8篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2003年 | 1篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有85条查询结果,搜索用时 46 毫秒
1.
A stochastic damage mechanics failure model of composites This paper focuses on the theoretical simulation of strength and failure of specimens with nonlocal damage. A concept is proposed for quantitative interpretation and prediction of nonlinear. nominal stress-strain curves of damaged materials like fine ceramics or intermetallic alloys. For that reason methods of damage mechanics and of probability theory are combined. 相似文献
2.
The present study was initiated to assess time-course and risk factors for the development of cataract and posterior-capsule opacification as well as complications of cataract surgery and YAG-laser capsulotomy following vitrectomy for diabetic retinopathy. The charts of all patients undergoing vitrectomy for diabetic retinopathy during a 5-year period in a university eye hospital were retrospectively reviewed. The course of 306 consecutive eyes in which the lens was retained during vitrectomy was analyzed for subsequent cataract surgery and YAG-laser capsulotomy. The first 6 months after cataract or YAG-laser surgery were examined for the occurrence of complications. Data were analyzed with regard to the time course using Kaplan-Meier life-table analysis. The proportion of eyes that underwent cataract surgery after vitrectomy increased nearly linearly with time, approaching 75% after 5 years. Silicone tamponade (relative risk 1.9; P = 0.0005) and transscleral retinal cryotherapy (relative risk 1.4; P = 0.003) were risk factors for subsequent cataract surgery. No significant cataractogenous effect of intravitreal gas as compared with balanced salt solution was found. YAG-laser capsulotomy was performed in 60% of vitrectomized diabetic eyes within 2 years but in only 10% of nondiabetic controls (P < 0.0001). Within 6 months of extracapsular cataract surgery with implantation of an intraocular lens (IOL) in 54 eyes, no serious complication was observed. After YAG-laser capsulotomy, vitreous hemorrhage occurred within 6 months in 6 of 21 eyes. In conclusion, cataract surgery was performed in 75% of the phakic eyes within 5 years of vitrectomy for diabetic retinopathy. Posterior capsular opacification is particularly common in this subset of eyes. No serious complication was observed after extracapsular cataract surgery with IOL implantation, but YAG-laser capsulotomy was associated with an increased risk for vitreous hemorrhage. 相似文献
3.
4.
5.
Ebony A. Monson Donna R. Whelan Karla J. Helbig 《International journal of molecular sciences》2021,22(9)
Lipid droplets (LDs) have traditionally been thought of as solely lipid storage compartments for cells; however, in the last decade, they have emerged as critical organelles in health and disease. LDs are highly dynamic within cells, and their movement is critical in organelle–organelle interactions. Their dynamics are known to change during cellular stress or nutrient deprivation; however, their movement during pathogen infections, especially at very early timepoints, is under-researched. This study aimed to track LD dynamics in vitro, in an astrocytic model of infection. Cells were either stimulated with a dsRNA viral mimic, poly I:C, or infected with the RNA virus, Zika virus. Individual LDs within infected cells were analysed to determine displacement and speed, and average LD characteristics for multiple individual cells calculated. Both LD displacement and mean speed were significantly enhanced in stimulated cells over a time course of infection with an increase seen as early as 2 h post-infection. With the emerging role for LDs during innate host responses, understanding their dynamics is critical to elucidate how these organelles influence the outcome of viral infection. 相似文献
6.
We introduce two new concepts for?-efficiency and investigate these and some known concepts under the following aspects: (1) What are the relationships between the efficient and the?-efficient point set? (2) If the sequence (v ?) of?-efficient points converges forε → 0, is the limit efficient, or weakly efficient? (3) Can the distance between the?-efficient and the efficient point set be estimated in terms ofε? 相似文献
7.
The determination of grain boundary planes in multicrystalline material has only been restricted to transmission electron microscope investigations (Jang et al., 1992; Elgat et al., 1985) or to metallograpical investigations of the grain boundary (Randle et al., 1993). The first method is expensive, and both are complex and time consuming in grain boundary preparation. This paper proposes the determination of grain boundary planes in semiconductor wafer by a combined application of Electron Back Scatter Diffraction and Infrared Transmission Microscopy. In particular, the new method is demonstrated with directional solidificated multicrystalline silicon. 相似文献
8.
9.
New oligofunctional surfactants prepared from ethyl 2-aminododecanoate hydrochloride and positional isomers of aromatic acid
di- and trichlorides via amide bond formation, including also the monofunctional compound of comparison, have been synthesized. Surface properties
of the new compounds, in particular critical micelle concentration (CMC), surface tension at the CMC, effectiveness, and maximum
surface excess, were determined. Moreover, their effectiveness at flotation using the model mineral fluorite was studied.
We found that the surfactant parameters clearly depend on the number and position of the amphiphilic subunits attached to
the aromatic core. We also found that a bundling of amphiphilic subunits, as performed, is profitable in the flotation of
fluorite and that effects of preorganization due to the proximity and geometric grouping of the amphiphilic subunits are of
importance. As a rule, the more amphiphilic subunits are included in the surfactant structure, the more efficient is the collecting
agent, involving approximate enhancements of fluorite flotation by powers of 10 when going from mono- to bi- and trifunctional
surfactant analogs, respectively. Nevertheless, the surface properties of the newly synthesized surfactants do not directly
correlate with the flotation data, which makes relations between surfactant structure and efficiency of fluorite flotation
at the current stage of development difficult to determine. Future studies relating to this problem are suggested. 相似文献
10.
We show how to use the reciprocity between electroluminescence and solar cell quantum efficiency for the simulation and interpretation of electroluminescence images. The analysis of the spectral properties of the electroluminescence images obtained by using different short- and long-pass filters yields information about surface recombination velocity, bulk diffusion length and reflection of the back side in flat and textured solar cells. 相似文献