全文获取类型
收费全文 | 2823篇 |
免费 | 220篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 54篇 |
综合类 | 6篇 |
化学工业 | 818篇 |
金属工艺 | 67篇 |
机械仪表 | 87篇 |
建筑科学 | 160篇 |
矿业工程 | 3篇 |
能源动力 | 55篇 |
轻工业 | 279篇 |
水利工程 | 11篇 |
石油天然气 | 2篇 |
无线电 | 210篇 |
一般工业技术 | 601篇 |
冶金工业 | 236篇 |
原子能技术 | 10篇 |
自动化技术 | 447篇 |
出版年
2023年 | 17篇 |
2022年 | 37篇 |
2021年 | 72篇 |
2020年 | 46篇 |
2019年 | 68篇 |
2018年 | 82篇 |
2017年 | 102篇 |
2016年 | 107篇 |
2015年 | 105篇 |
2014年 | 115篇 |
2013年 | 172篇 |
2012年 | 145篇 |
2011年 | 193篇 |
2010年 | 114篇 |
2009年 | 131篇 |
2008年 | 144篇 |
2007年 | 137篇 |
2006年 | 113篇 |
2005年 | 87篇 |
2004年 | 63篇 |
2003年 | 68篇 |
2002年 | 46篇 |
2001年 | 45篇 |
2000年 | 50篇 |
1999年 | 44篇 |
1998年 | 80篇 |
1997年 | 60篇 |
1996年 | 50篇 |
1995年 | 43篇 |
1994年 | 26篇 |
1993年 | 38篇 |
1992年 | 25篇 |
1991年 | 23篇 |
1990年 | 18篇 |
1989年 | 24篇 |
1988年 | 20篇 |
1987年 | 16篇 |
1986年 | 26篇 |
1985年 | 22篇 |
1984年 | 21篇 |
1983年 | 16篇 |
1982年 | 14篇 |
1981年 | 19篇 |
1980年 | 13篇 |
1979年 | 21篇 |
1978年 | 23篇 |
1977年 | 18篇 |
1976年 | 20篇 |
1974年 | 14篇 |
1973年 | 12篇 |
排序方式: 共有3046条查询结果,搜索用时 15 毫秒
1.
2.
High‐intensity sweeteners in espresso coffee: ideal and equivalent sweetness and time–intensity analysis
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bruna M. Azevedo Flávio L. Schmidt Helena M. A. Bolini 《International Journal of Food Science & Technology》2015,50(6):1374-1381
The efficient substitution of sucrose by a sweetener in beverages requires the application of some sensory techniques. First, one must determine the concentrations of the sweeteners under study, equivalent in sweetness to the ideal sucrose concentration. In addition, it is fundamental to determine which is most similar to sucrose. The objectives of this study were to determine the ideal sweetness for espresso coffee and the equivalent concentrations in sweetness of different sweeteners, as well as characterise the time–intensity profile of each sweetener in relation to sweetness. The sweeteners evaluated were sucralose, aspartame, neotame, a cyclamate/saccharin mixture (2:1) and stevia. The sucrose concentration considered ideal by consumers was 12.5% (w/v), and the equivalent concentrations of the sweeteners were 0.0159% for sucralose, 0.0549% for aspartame, 0.0016% for neotame, 0.0359% for the cyclamate/saccharin mixture and 0.0998% for stevia. The time–intensity analysis indicated that possibly the sweeteners neotame, aspartame and sucralose would be the best substitutes for sucrose. 相似文献
3.
Pavel Strunz Debashis Mukherji Přemysl Beran Ralph Gilles Lukas Karge Michael Hofmann Markus Hoelzel Joachim Rösler Gergely Farkas 《Metals and Materials International》2018,24(5):934-944
An addition of boron largely increases the ductility in polycrystalline high-temperature Co–Re alloys. Therefore, the effect of boron on the alloy structural characteristics is of high importance for the stability of the matrix at operational temperatures. Volume fractions of ε (hexagonal close-packed—hcp), γ (face-centered cubic—fcc) and σ (Cr2Re3 type) phases were measured at ambient and high temperatures (up to 1500 °C) for a boron-containing Co–17Re–23Cr alloy using neutron diffraction. The matrix phase undergoes an allotropic transformation from ε to γ structure at high temperatures, similar to pure cobalt and to the previously investigated, more complex Co–17Re–23Cr–1.2Ta–2.6C alloy. It was determined in this study that the transformation temperature depends on the boron content (0–1000 wt. ppm). Nevertheless, the transformation temperature did not change monotonically with the increase in the boron content but reached a minimum at approximately 200 ppm of boron. A probable reason is the interplay between the amount of boron in the matrix and the amount of σ phase, which binds hcp-stabilizing elements (Cr and Re). Moreover, borides were identified in alloys with high boron content. 相似文献
4.
A central event in the life of a cellular system is the interaction between the exterior and the interior compartments. Biochemical signals arrive at the cellular surface, bind to their membrane bound receptor followed by a conformational change triggering the release of an internal chemical or electrical signal.This basic principle is followed by all our perceptive abilities like sense of smell or taste, but also by different signal transduction pathways involved in nerve conductivity, vision, sense of touch or hearing. To follow and mimic this principle of parallel registration is one of the aims of modern nanobiotechnology. If we are able to specifically biofunctionalize small arrays of a solid surface, which could be an electrode or a semiconductor, this approach will enable us to build up devices called “biochips” or “biosensors” that allow the determination of bioactive molecules with high specificity at lowest concentrations. Potential pharmacological active substrates might be screened as well as new receptors may be determined. Applications in genomics as well as proteomics are realistic. The major prerequisite for such a broad spectrum of applications is the fabrication of receptive surfaces. Biomolecules have to be surface‐adsorbed in a highly reproducible, oriented and well organised fashion, a task which in biology is taken by the cellular membranes as external or internal receptive surfaces. The physical principles like hydrogen bonds, electrostatic or hydrophobic interactions that lead to such an organized surface are well known. To synthesize molecular building blocks and to position them onto an otherwise unspecific surface is one of the challenges of nanobiotechnology combining biological knowledge and chemical skills with biophysical techniques that allow to handle or analyze even single molecules. 相似文献
5.
6.
Matthias Zobel Joachim Denzler Benno Heigl Elmar Nöth Dietrich Paulus Jochen Schmidt Georg Stemmer 《Machine Vision and Applications》2003,14(1):26-34
Abstract. This contribution introduces MOBSY, a fully integrated, autonomous mobile service robot system. It acts as an automatic dialogue-based
receptionist for visitors to our institute. MOBSY incorporates many techniques from different research areas into one working
stand-alone system. The techniques involved range from computer vision over speech understanding to classical robotics.
Along with the two main aspects of vision and speech, we also focus on the integration aspect, both on the methodological
and on the technical level. We describe the task and the techniques involved. Finally, we discuss the experiences that we
gained with MOBSY during a live performance at our institute. 相似文献
7.
8.
A theoretical model is presented by which a true expression of pregnancy rate resulting from stimulated cycles can be calculated. This includes the transfer of both fresh and cryopreserved embryos. It is concluded that the total reproductive potential of a single cycle of stimulation can only be evaluated by including pregnancies arising from all fresh and frozen embryo transfers resulting from that cycle. 相似文献
9.
Flávio A. Pavan Sidinei A. Gobbi Celso C. Moro Tania M.H. Costa Edilson V. Benvenutti 《Journal of Porous Materials》2002,9(4):307-311
Anilinepropylsilica hybrid powder was synthesized by a sol-gel route in basic medium using HF as catalyst. The effect of the amount of HF catalyst on the morphologies and on organic content was studied. The xerogels were characterized using FTIR, SEM and N2 adsorption-desorption isotherms. The increase in the HF quantity results in an slight increase in organic content and changes in the particle size, surface area and pore structure. 相似文献
10.