全文获取类型
收费全文 | 1118篇 |
免费 | 91篇 |
国内免费 | 1篇 |
学科分类
工业技术 | 1210篇 |
出版年
2024年 | 3篇 |
2023年 | 11篇 |
2022年 | 18篇 |
2021年 | 79篇 |
2020年 | 34篇 |
2019年 | 42篇 |
2018年 | 43篇 |
2017年 | 43篇 |
2016年 | 59篇 |
2015年 | 44篇 |
2014年 | 46篇 |
2013年 | 88篇 |
2012年 | 80篇 |
2011年 | 88篇 |
2010年 | 69篇 |
2009年 | 64篇 |
2008年 | 90篇 |
2007年 | 67篇 |
2006年 | 58篇 |
2005年 | 31篇 |
2004年 | 26篇 |
2003年 | 19篇 |
2002年 | 29篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有1210条查询结果,搜索用时 15 毫秒
71.
The melt processability and physico‐mechanical properties of blends of natural rubber (NR) and ethylene propylene diene rubber (EPDM) containing different dosages (0–10 phr) of phosphorylated cardanol prepolymer (PCP) were studied in unfilled and china‐clay‐filled mixes. The plasticizing effect of PCP in the blends was evidenced by progressive reduction in power consumption of the mixing and activation energy for melt flow with an increase in the dosage of PCP. The PCP‐modified blend vulcanizates showed higher tensile properties and tear strength despite a decrease in the chemical crosslink density (CLD) index. This is presumably due to the formation of a crosslinked network structure of PCP with the rubbers and improved dispersion of the filler particles in the rubber matrix, as evidenced by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Thermogravimetric analysis showed an increase in thermal stability of the blend vulcanizate in presence of 5 phr of PCP. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5123–5130, 2006 相似文献
72.
Dietary fiber and antioxidants are food constituents and functional ingredients that are generally addressed separately. Nowadays there is scientific evidence that primary characteristics of DF assigned to non starch polysaccharides and lignin (resistance to digestion and absorption in the small intestine and fermentation in the large intestine) can be extended to other indigestible food constituents that are resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine. The antioxidant dietary fiber concept was defined as a dietary fiber concentrate containing significant amounts of natural antioxidants associated with non digestible compounds. Hibiscus sabdariffa L flower shows in its composition an important percentage of dietary fiber and high antioxidant capacity. The infusion obtained by decoction of flowers, had been extensibility studied due to the healthy properties. In this work the principal nutritional aspects from Hibiscus sabdariffa L and its use as a possible antioxidant dietary fiber source had been considered. 相似文献
73.
ABSTRACT Regardless of the fast-growing popularity of shrinking cities in the literature, certain misconceptions persist. Urban shrinkage is often assumed to be near-synonymous with urban distress, and shrinking cities are assumed to be in need of growth. In this paper, we seek to achieve a greater conceptual clarity for both shrinkage and distress, thereby informing present debates on the topic and inviting more nuanced ones in the future. The paper is organized in three main parts. We first use a historical lens to challenge the conflation of shrinkage and distress. Western history is rife with examples of when growth—shrinkage’s opposite—was associated with distress. Second, we comment on some contradictions in the conceptual currents that underlie the idea of shrinking as distress, particularly in the United States. Third, we highlight how shrinkage may benefit cities and the people who live in them. 相似文献
74.
Sonia A. Hirt 《International Planning Studies》2005,10(3-4):219-240
This paper examines adjustments of the urban planning process to the post-communist context in the case of Sofia, the capital of Bulgaria. The main research question is whether master-planning processes have substantially changed from top-down and technocratic (as they certainly were in fascist and then communist Bulgaria) to open and participatory today. The paper tells the story of four master plans—one pre-communist, two communist, and one post-communist. It concludes that despite the increased capacity of the citizenry to both influence and challenge government planning and decision-making, there is little evidence of sharp discontinuity between past and present planning processes. 相似文献
75.
Cereals are a very important part of the human and animal diets. However, agricultural products can be contaminated by moulds and their mycotoxins. Plant extracts, particularly those of Equisetum arvense and Stevia rebaudiana have been reported previously to contain antioxidant compounds which may have antifungal properties. In this study, E. arvense and S. rebaudiana extracts were tested for their control of mycotoxigenic fungi in maize. The extracts were tested separately and as a mixture for their effect on growth of Aspergillus flavus and Fusarium verticillioides. Extracts were added to unsterilised inoculated maize at different water activity (a(w)) levels (0.85-0.95). Moulds were inoculated and incubated for 30 days. Results confirmed that the extract of E. arvense and a mixture 1:1 of Equisetum-Stevia may be effective for the inhibition of both growth of A. flavus and aflatoxin production at high water activity levels (pre-harvest conditions). In general, growth of the F. verticillioides was reduced by the use of plant extracts, especially at 0.95 a(w). However, fumonisin presence was not significantly affected. E. arvense and S. rebaudiana extracts could be developed as an alternative treatment to control aflatoxigenic mycobiota in moist maize. 相似文献
76.
Study on the applicability of high-pressure homogenization for the production of banana juices 总被引:1,自引:0,他引:1
Sonia Calligaris Martina Foschia Ingrid Bartolomeoli Michela Maifreni Lara Manzocco 《LWT》2012,45(1):117-121
The aim of this preliminary study was to evaluate the potential applicability of high-pressure homogenization (HPH) for the production of banana juices. To this purpose, a prototype equipment working up to 400 MPa and a lab-scale homogenizer working up to 150 MPa were used. Temperature, microbial load, pectate lyase activity, colour and viscosity of the samples homogenized at increasing pressure were evaluated. Pressures higher than 200 MPa were needed to obtain 4 log unit reduction of total mesophilic bacteria and pectate lyase inactivation. Following HPH, banana juice resulted brighter and less viscous than the untreated one. Data suggest that HPH treatments could be a reliable technological alternative to conventional heat treatments for the production of added-value fruit juices. However, the homogenization design could play a critical role in affecting the product quality attributes. In fact, homogenization performed at the same operative pressure by using different equipment leads to different effects on product quality. 相似文献
77.
García-Cela E Ramos AJ Sanchis V Marin S 《Journal of the science of food and agriculture》2012,92(7):1455-1461
BACKGROUND: The presence of ochratoxin A (OTA) in grapes and grape derivatives has been reported mainly in the Mediterranean area. Consequently, great efforts are being made to prevent the growth of Aspergillus on grapes. However, the European Commission suggests that climate change may result in increased temperatures and longer drought periods in southern Europe. Therefore the aim of this study was to investigate how ochratoxigenic fungal growth and the efficiency of fungicides used at present might be affected by environmental conditions predicted with climate change. RESULTS: The effectiveness of grape field antifungals (Switch, Flint Max and Equisetum arvense extract) under two alternating temperature, photoperiod and relative humidity (RH) scenarios (current: 20/30 °C, 16 h light/8 h darkness, 80% RH; predicted: 25/37 °C, 16 h light/8 h darkness, 75% RH) on the growth and OTA production of two Aspergillus carbonarius isolates and one Aspergillus ochraceus isolate on grapes was investigated. CONCLUSION: Predicted conditions reduced A. carbonarius and limited A. ochraceus growth. Antifungals reduced fungal infection (by 40‐84%), although no correlation between climatic conditions and effectiveness of the antifungals was found. However, Switch always showed the greatest reduction and E. arvense (0.02 g mL?1 extract) the least. Higher temperatures affected OTA production by the isolates in different ways. In general, Switch and Flint Max reduced OTA production, while E. arvense stimulated it. Copyright © 2011 Society of Chemical Industry 相似文献
78.
María C. Doporto Cecilia Dini Alicia Mugridge Sonia Z. Viña María A. García 《Journal of food engineering》2012
The aims of this work were to analyze physicochemical and thermal properties of ahipa and cassava flours and starches and to determine their water sorption isotherms and thermodynamic properties. Both flours are naturally gluten-free products, obtained by relatively simple procedures (grating or slicing). Ahipa flour gelatinized at lower temperature than cassava, indicating a better aptitude for cooking. Gelatinization temperatures of flours were higher than those of their starches. Water holding capacity of ahipa flours was significantly higher than those of cassava, leading the slicing process the highest values. Sorption isotherms were determined at 10, 20 and 30 °C. Experimental data were satisfactorily fitted using different mathematical models. Thermodynamic parameters associated with water adsorption process were calculated from GAB model, as well as the monolayer water content. All samples could be considered as products with an acceptable stability. 相似文献
79.
Thirty-two Merino lambs fed barley straw and a concentrate alone (CONTROL group) or enriched with carnosic acid [0.6 g kg(-1) dry matter (DM), CARN006 group; 1.2 g kg(-1) DM, CARN012 group] or vitamin E (0.6 g kg(-1) DM, VITE006 group) were used to assess the effect of these antioxidant compounds on meat quality. After being fed the experimental diets for at least 5 weeks, the animals were slaughtered with the 25 kg intended body weight and the different muscles (longissimus lumborum; LL, gluteus medius; GM) were sliced and kept refrigerated under modified atmosphere packaging during 0, 7 and 14 days. The results indicate that carnosic acid seemed to be useful to delay lipid peroxidation in a medium colour-stable muscle such as GM, but this effect was lower than that observed when vitamin E was supplemented to fattening lambs. On the contrary, meat texture and protection against cholesterol oxidation were equally improved with both compounds. 相似文献
80.
Montouto-Graña M Cabanas-Arias S Porto-Fojo S Vázquez-Odériz ML Romero-Rodríguez MA 《Journal of food science》2012,77(1):S40-S46
For a new product to succeed in the market, it must be accepted by consumers. This study investigates consumer opinions on fresh-cut potatoes packaged under vacuum and under a modified atmosphere using home use tests. The data obtained were related to demographic characteristics and patterns of consumption and to purchase intention toward potatoes and other vegetables. The sensory characteristics evaluated by a panel of assessors trained in the sensory evaluation of potato were also considered. The results indicate that although both products were accepted by the consumer, vacuum-packed potatoes received slightly higher ratings and more consumers intended to purchase this product. PRACTICAL APPLICATION: The fresh-cut potato packaged under vacuum is a product with all the sensory characteristics that will be accepted by the consumers. The adaptation to the productive process at the industrial level, it can be performed with enough guarantees that the product will definitely be purchased by the consumers. 相似文献