全文获取类型
收费全文 | 424篇 |
免费 | 15篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 133篇 |
金属工艺 | 3篇 |
机械仪表 | 4篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 5篇 |
轻工业 | 88篇 |
水利工程 | 2篇 |
无线电 | 20篇 |
一般工业技术 | 59篇 |
冶金工业 | 74篇 |
原子能技术 | 1篇 |
自动化技术 | 38篇 |
出版年
2023年 | 2篇 |
2022年 | 11篇 |
2021年 | 14篇 |
2020年 | 10篇 |
2019年 | 6篇 |
2018年 | 13篇 |
2017年 | 9篇 |
2016年 | 11篇 |
2015年 | 4篇 |
2014年 | 14篇 |
2013年 | 24篇 |
2012年 | 13篇 |
2011年 | 31篇 |
2010年 | 26篇 |
2009年 | 17篇 |
2008年 | 18篇 |
2007年 | 22篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1995年 | 2篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1973年 | 2篇 |
1966年 | 3篇 |
1961年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有439条查询结果,搜索用时 15 毫秒
311.
Jury instructions on damage awards are notoriously vague and ambiguous. As a result, awards are sometimes unexpected and seemingly illogical. In this article, the authors argue that jury instructions regarding damages are vague because the law of damages itself is purposefully ambiguous—allowing particularized justice across a variety of different circumstances. The authors review research on comprehension and application of substantive jury instructions related to damages and on procedural variations at trial (e.g., use of preinstruction, bifurcation, blindfolding jurors to various issues, special verdict forms, caps on damages, and instruction revision) that impact the substantive instructions that jurors receive from the judge. They comment on attempts at reforming jury instructions regarding damages and conclude that jurors' decision making on this difficult and emotional issue could be made more predictable by careful reforms at the trial level. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
312.
313.
Stephen Derenzo Gregory BizarriRamesh Borade Edith Bourret-CourchesneRostyslav Boutchko Andrew CanningAnurag Chaudhry Yetta EaglemanGautam Gundiah Stephen HanrahanMartin Janecek Marvin Weber 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,652(1):247-250
We report the scintillation luminosities, decay times, and emission wavelengths for 19 Ce3+ activated scintillators, 18 Eu2+ activated scintillators, and 4 self-activated scintillators. Of these, 18 have not been previously reported either as phosphors or scintillators. Their luminosities range from 40,000 to under 1000 photons/MeV. While these scintillators may not have properties that make them top candidates for widespread use, their data will contribute to a deeper understanding of factors that limit scintillator performance. 相似文献
314.
315.
Jamet M Barski A Devillers T Poydenot V Dujardin R Bayle-Guillemaud P Rothman J Bellet-Amalric E Marty A Cibert J Mattana R Tatarenko S 《Nature materials》2006,5(8):653-659
The emerging field of spintronics would be dramatically boosted if room-temperature ferromagnetism could be added to semiconductor nanostructures that are compatible with silicon technology. Here, we report a high-TC (>400K) ferromagnetic phase of (Ge,Mn) epitaxial layer. The manganese content is 6%, and careful structural and chemical analyses show that the Mn distribution is strongly inhomogeneous: we observe eutectoid growth of well-defined Mn-rich nanocolumns surrounded by a Mn-poor matrix. The average diameter of these nanocolumns is 3nm and their spacing is 10nm. Their composition is close to Ge(2)Mn, which corresponds to an unknown germanium-rich phase, and they have a uniaxially elongated diamond structure. Their Curie temperature is higher than 400K. Magnetotransport reveals a pronounced anomalous Hall effect up to room temperature. A giant positive magnetoresistance is measured from 7,000% at 30K to 200% at 300K and 9T, with no evidence of saturation. 相似文献
316.
Effect of low and high acetylation degree in the morphological, physicochemical and structural characteristics of barley starch 总被引:2,自引:0,他引:2
Luis A. Bello-Pérez Edith Agama-Acevedo Paul B. Zamudio-Flores Guadalupe Mendez-Montealvo Sandra L. Rodriguez-Ambriz 《LWT》2010,43(9):1434-1440
Barley starch was acetylated at two levels (low degree: LD (0.9), and high degree: HD (2.7)) substitution and the morphological, physicochemical and structural of the resultant acetylated barley starch were determined. The acetylated barley starches presented the signal at 1226 cm−1 that corresponds to the C-O stretching of acetyl groups. The morphological study showed fusion of starch granules in the acetylated starch with HD. This effect was evident in the pasting test, because the viscoamylograph profile of HD starch showed the absence in peak viscosity, viscosity breakdown and viscosity setback. The peak gelatinization was similar for native and LD and decrease in the HD acetylated starch. The gelatinization enthalpy value showed difference among the samples, indicating that the loss of the ordered double helices more than the crystallinity loss was higher in the HD acetylated barley starch. In the retrogradation test, acetylation affected both retrogradation and enthalpy value, because acetylated barley starch with HD substitution at three storage days had 3.2 j/g and with LD 4.8 j/g. The molecular weight and z-average radius of gyration values decreased due to the acetylation process, indicating depolymerization of starch components as it was evidenced by the increase in short chains level in the acetylated samples. 相似文献
317.
Paola I. Angulo-Bejarano Nadia M. Verdugo-Montoya Edith O. Cuevas-Rodríguez Jorge Milán-Carrillo Rosalva Mora-Escobedo Jose A. Lopez-Valenzuela José A. Garzón-Tiznado Cuauhtémoc Reyes-Moreno 《Food chemistry》2008
The effects of solid state fermentation (SSF) on physicochemical and nutritional properties of chickpea flour were studied. Fermented (tempeh) flour showed higher particle size index, gelatinization temperature, dispersability and resistant starch content, and lower gelatinization enthalpy and water solubility than unfermented flour. SSF increased the content of the essential amino acids (EAA) Ile, total sulphur (Met + Cys), total aromatic (Phe + Tyr), and Thr in 37, 41, 107, and 39 g kg−1 protein, respectively; Trp content decreased 8 g kg−1 protein. Total sulphur (EAA score = 0.87) was limiting in unfermented flour and Trp (0.93) in tempeh flour. SSP improved the in vitro and true protein digestibility (72.2–83.2% and 83.7–88.8%, respectively), protein efficiency ratio (PER, 1.59–2.31), cPER (1.54–2.21), and corrected protein digestibility (0.73–0.89). Chickpea tempeh flour may be considered for the fortification of widely consumed legume-based food products. 相似文献
318.
Marion Thébault Uwe Müller Andreas Kandelbauer Edith Zikulnig-Rusch Herfried Lammer 《Holz als Roh- und Werkstoff》2017,75(6):853-876
The resins used in impregnation of the core layers of Kraft paper-based decorative laminates are basically synthetized from phenol and formaldehyde (PF). The increasing costs of phenol force laminates manufacturers to search for alternatives or partial substitution products to reduce consumption of this chemical. Preferably, such PF alternative substitutes are environmentally friendly bio-based phenolic compounds, such as lignin, tannins, or cashew nut shell liquid. However, substitution raises some technological issues in the impregnation process due to the chemical variability of these natural raw materials and their different properties from phenol. These differences do not only have an influence on the technological behavior of the modified resins during impregnation and laminate pressing, but also require inclusion of new or modified processes such as biomass treatment (down-streaming, modification of natural polyphenols, activation, etc.) or novel synthetic procedures. Moreover, the use of resins containing natural compounds in the laminates manufacture can result in products with minor mechanical properties. This article provides a general overview of the most promising candidates of such bio-based materials and deals with the most important issues when it comes to their incorporation into PF resins. Due to their abundance on Earth, much knowledge of lignin-based materials has already been gained and uses of lignin in PF resins have been studied for many decades. Other natural polyphenols that are less frequently considered for impregnation are covered as well, as they do also possess some potential for PF substitution. 相似文献
319.
320.
Different defect chemical models for calculation of ionic and electronic defect concentrations are discussed regarding their applicability to transition metal perovskite-type oxides (ABO3 – ) with large ranges of oxygen non-stoichiometry. A point defect model, which allows simultaneous consideration of three different B-site species concentrations as a function of the oxygen partial pressure is compared to a simple point defect model, considering only two different B-site species. Additionally, a model assuming electrons/holes as negative resp. positive electronic charge carriers is presented. Further, models involving association of point defects in different complexes are discussed. Examples are given for fits of experimental data of La1 – xSrxBO3 – (x = 0.6, B = Fe, Co) to selected models in the temperature range 700–900_C and oxygen partial pressures 10– 5 < pO2/atm < 1. 相似文献