全文获取类型
收费全文 | 122篇 |
免费 | 5篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 2篇 |
综合类 | 7篇 |
化学工业 | 24篇 |
金属工艺 | 3篇 |
机械仪表 | 5篇 |
建筑科学 | 18篇 |
能源动力 | 1篇 |
轻工业 | 36篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 3篇 |
一般工业技术 | 14篇 |
冶金工业 | 3篇 |
自动化技术 | 10篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 6篇 |
2013年 | 10篇 |
2012年 | 6篇 |
2011年 | 11篇 |
2010年 | 11篇 |
2009年 | 5篇 |
2008年 | 2篇 |
2007年 | 10篇 |
2006年 | 4篇 |
2005年 | 11篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 6篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1994年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1977年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有132条查询结果,搜索用时 15 毫秒
1.
2.
Ilija Ilić Peter Kása Jr. Klara Pintye-Hódi Stane Srčič 《Drug development and industrial pharmacy》2013,39(10):1271-1280
Objective: The purpose of this study was to investigate and quantify flow properties, compressibility, and compactibility of various pharmaceutical lactose powders found on the market today (DCL-11, DCL-21, M‐200, Flowlac-100, and Tablettose 70, 80, and 100). Methods: Flow properties were estimated by measuring flow time, angle of repose, and the Hausner ratio. Particle rearrangement was studied using Kawakita's linear model. Compressibility was studied using two ‘out-of-die’ methods: (i) the Heckel model and (ii) a modified Walker model. Compactibility was quantified using two methods: (i) the tensile strength profile (Cp) and (ii) the compactibility factor (Pr). Statistical approach was used to analyze the results. Results: Flow properties of all materials were passable or better, except for M-200, which has very poor flowability. Compressibility results demonstrated that the most compressible lactose is spray-dried grade of lactose (Flowlac-100) and the least compressible is milled lactose (M-200). Compactibility studies showed that β‐lactose (DCL-21) forms tablets with superior tensile strength in comparison with α-lactose. Conclusion: Results of the compressibility study showed that the discriminative power of modified Walker model is greater in comparison with Heckel model. Compactibility methods yield similar and comparable results. 相似文献
3.
N. E. DOWLING 《Fatigue & Fracture of Engineering Materials & Structures》2009,32(12):1004-1019
A mean stress equation can be incorporated into the strain–life curve in a manner that is consistent with the stress-based use of the same equation. Doing so for the Walker mean stress relationship gives excellent results for a number of strain–life data sets with non-zero mean stresses, including data on steels, one titanium alloy and aluminium alloys. This approach has a number of advantages: All data at all mean stresses can be combined into a single fitting procedure to determine the constants for the stress–life curve, which values also apply to the elastic strain term of the strain–life curve. The Walker parameter γ that also arises from this fitting is related to the sensitivity of the material to mean stress, giving this approach a versatility that is not possessed by other common mean stress methods. Where non-zero mean stress data are not available to obtain γ from fitting, an equation based on existing fitted values can be used to make estimates for steels. For precipitation-hardened aluminium alloys in the 2000 and 7000 series, an estimate of γ= 0.5 may be applied, so that the method becomes similar to that of Smith, Watson and Topper. For other metals, a default estimate of γ= 0.5 is suggested. For life estimates using the strain-based approach, it is recommended that the Walker mean stress method, incorporated into the strain–life curve, should be employed as an alternative to other methods, or perhaps to even replace them entirely. 相似文献
4.
Felicity D Scott 《Architectural Design》2015,85(3):78-85
Felicity D Scott , Associate Professor of Architecture at Columbia University Graduate School of Architecture, Planning and Preservation (GSAPP), describes here the instant city events of the early 1970s. These foreshadowed current global village media practices in what now seems a quaintly material manner: communication between sites involved the physical mailing of videotapes and ‘wire photos’ through the postal service. The sites themselves – in the US and elsewhere – were transformed into ‘instant cities’ through the erection of physical geodesic domes, teepees and inflatables in seas of mud. The true antecedents of today's instant networking, these pioneers embraced the newest technology available at the time and the most innovative forms of temporary architecture. 相似文献
5.
随着科学技术的进步和人们对于增强自身能力的渴望,下肢外骨骼助行机器人已成为国内外"人机一体化"的一个重要研究方向。根据研究工作积累和文献资料调研,总结了国内外主要研究机构对于下肢外骨骼助行机器人的研究现状,分析了下肢外骨骼助行机器人研制需要解决的关键技术,对下肢外骨骼助行机器人的发展趋势进行了预测。研究工作表明:下肢外骨骼助行机器人在穿戴性、智能化以及便携性等方面都有了突破性的发展,但是应当加强对微型能源、轻质便携材料、多功能系统等的研究和开发,才能广泛应用于军事、科考、旅游、交通、救灾等领域。 相似文献
6.
分析柘林水库泄水放空洞台车式启闭机手动行走装置运行中存在的问题,提出改造设计思路,并进行主要参数计算和设备选型. 相似文献
7.
In arid regions, reductions in the amount of available agricultural water are fueling interest in alternative, low water-use crops. Perennial grasses have potential as low water-use biofuel crops. However, little is known about which perennial grasses can produce high quantity, high quality yields with low irrigation on formerly high-input agricultural fields in arid regions. We monitored biomass production, weed resistance, rooting depth, and root architecture of nine perennial grasses under multiple irrigation treatments in western Nevada. Under a low irrigation treatment (71 ± 9 cm irrigation water annually), cool-season grasses produced more biomass and were more weed-resistant than warm-season grasses. With additional irrigation (120 ± 12 cm water annually), warm- and cool-season grasses had similar biomass production, but cool-season species remained more weed-resistant. Among species within each grass type, we observed high variability in performance. Two cool-season species (Elytrigia elongata and Leymus cinereus) and one warm-season species (Bothriochloa ischaemum) performed better than the other tested species. Root depth was not correlated with biomass production, but species with deeper roots had fewer weeds. Abundance of fine roots (but not large roots) was correlated with increased biomass and fewer weeds. Both L. cinereus and E. elongata had deep root systems dominated by fine roots, while B. ischaemum had many fine roots in shallow soil but few roots in deeper soil. Cool-season grasses (particularly E. elongata, L. cinereus, and other species with abundant fine roots) may be worthy of further attention as potential biofuel crops for cold desert agriculture. 相似文献
8.
ZHANG Jing & WU MeiPing College of Mechatronics Engineering Automation National University of Defense Technology Changsha China 《中国科学:信息科学(英文版)》2011,(9)
The probability of the rendezvous between a single spacecraft and three non-coplanar constellation satellites is studied,and the necessary and sufficient conditions of the rendezvous without orbital maneuver are deduced.The rendezvous orbit design can be transformed into the patching of two spacecraft orbits,either of which can achieve the rendezvous with two satellites.Firstly,due to the precious quality of spherical geometry,the unique existence of the rendezvous orbit for two constellation satellites is ... 相似文献
9.
本文以彼得沃克代表作伯奈特公园设计为案例,就极简主义景观设计风格进行探索,旨在推动我国景观设计的新发展。 相似文献
10.
Abstract. The multi-variate t distribution provides a viable framework for modelling volatile time-series data; it includes the multi-variate Cauchy and normal distributions as special cases. For multi-variate t autoregressive models, we study the nature of the innovation distribution and the prediction error variance; the latter is nonconstant and satisfies a kind of generalized autoregressive conditionally heteroscedastic model. We derive the exact likelihood equations for the model parameters, they are related to the Yule–Walker equations and involve simple functions of the data, the model parameters and the autocovariances up to the order of the model. The maximum likelihood estimators are obtained by alternately solving two linear systems and illustrated using the lynx data. The simplicity of these equations contributes greatly to our theoretical understanding of the likelihood function and the ensuing estimators. Their range of applications are not limited to the parameters of autoregressive models; in fact, they are applicable to the parameters of ARMA models and covariance matrices of stochastic processes whose finite-dimensional distributions are multi-variate t . 相似文献