全文获取类型
收费全文 | 1611篇 |
免费 | 51篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 13篇 |
综合类 | 1篇 |
化学工业 | 482篇 |
金属工艺 | 32篇 |
机械仪表 | 9篇 |
建筑科学 | 66篇 |
矿业工程 | 3篇 |
能源动力 | 32篇 |
轻工业 | 176篇 |
水利工程 | 11篇 |
石油天然气 | 8篇 |
无线电 | 172篇 |
一般工业技术 | 298篇 |
冶金工业 | 143篇 |
原子能技术 | 13篇 |
自动化技术 | 213篇 |
出版年
2023年 | 8篇 |
2022年 | 12篇 |
2021年 | 19篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 20篇 |
2017年 | 25篇 |
2016年 | 27篇 |
2015年 | 26篇 |
2014年 | 42篇 |
2013年 | 87篇 |
2012年 | 58篇 |
2011年 | 99篇 |
2010年 | 67篇 |
2009年 | 72篇 |
2008年 | 91篇 |
2007年 | 64篇 |
2006年 | 72篇 |
2005年 | 50篇 |
2004年 | 62篇 |
2003年 | 52篇 |
2002年 | 69篇 |
2001年 | 33篇 |
2000年 | 33篇 |
1999年 | 37篇 |
1998年 | 33篇 |
1997年 | 20篇 |
1996年 | 25篇 |
1995年 | 24篇 |
1994年 | 27篇 |
1993年 | 25篇 |
1992年 | 24篇 |
1991年 | 16篇 |
1990年 | 18篇 |
1989年 | 23篇 |
1988年 | 19篇 |
1987年 | 15篇 |
1986年 | 16篇 |
1985年 | 30篇 |
1984年 | 13篇 |
1983年 | 23篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 20篇 |
1979年 | 18篇 |
1978年 | 15篇 |
1976年 | 17篇 |
1975年 | 20篇 |
1974年 | 10篇 |
1966年 | 7篇 |
排序方式: 共有1672条查询结果,搜索用时 0 毫秒
41.
Gwénaëlle Hourdin Alain Germain Claude Moreau François Fajula 《Catalysis Letters》2000,69(3-4):241-244
Ti‐BEA and Ti‐FAU, obtained by post‐synthesis treatment, and TS‐1, obtained by direct hydrothermal synthesis, have been tested
as catalysts for the Ruff oxidative degradation of calcium d‐gluconate to d‐arabinose using diluted hydrogen peroxide as oxidant.
Only large‐pore zeolites Ti‐BEA and Ti‐FAU were found to be active. It was shown, in particular, that a very rapid leaching
of titanium occurred and that the titanium species present in the solution were responsible for the catalytic activity observed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
42.
Claire C. Berton‐Carabin Marie‐Hélène Ropers Claude Genot 《Comprehensive Reviews in Food Science and Food Safety》2014,13(5):945-977
More polyunsaturated fats in processed foods and fewer additives are a huge demand of public health agencies and consumers. Consequently, although foods have an enhanced tendency to oxidize, the usage of antioxidants, especially synthetic antioxidants, is restrained. An alternate solution is to better control the localization of reactants inside the food matrix to limit oxidation. This review establishes the state‐of‐the‐art on lipid oxidation in oil‐in‐water (O/W) emulsions, with an emphasis on the role of the interfacial region, a critical area in the system in that respect. We first provide a summary on the essential basic knowledge regarding (i) the structure of O/W emulsions and interfaces and (ii) the general mechanisms of lipid oxidation. Then, we discuss the factors involved in the development of lipid oxidation in O/W emulsions with a special focus on the role played by the interfacial region. The multiple effects that can be attributed to emulsifiers according to their chemical structure and their location, and the interrelationships between the parameters that define the physicochemistry and structure of emulsions are highlighted. This work sheds new light on the interpretation of reported results that are sometimes ambiguous or contradictory. 相似文献
43.
Sorayya Azarnia Daniel St-Gelais Claude P. Champagne Kieran N. Kilcawley 《Food Biotechnology》2013,27(2):135-149
The use of recombinant aminopeptidase (PepN) from Lactobacillus rhamnosus S93 in free or encapsulated form was investigated to shorten the duration of Cheddar cheese ripening. Proteolysis was determined by measuring the soluble nitrogen as phosphotungstic acid (PTA-N) derivatives and free amino acids (FAA) over a 6-month period. The experimental cheeses received higher scores for sensory properties than the control cheese. The amounts of PTA-N and total FAA in the cheese with the encapsulated enzyme after 2 months of ripening were close to those of the control cheese after 6 months, suggesting the acceleration in proteolysis by about 4 months. 相似文献
44.
Oregano: chemical analysis and evaluation of its antimalarial, antioxidant, and cytotoxic activities
El Babili F Bouajila J Souchard JP Bertrand C Bellvert F Fouraste I Moulis C Valentin A 《Journal of food science》2011,76(3):C512-C518
Abstract: GC‐FID and GC‐MS analysis of essential oil from oregano leaves (Origanum compactum) resulted in the identification of 46 compounds, representing more than 98% of the total composition. Carvacrol was the predominant compound (36.46%), followed by thymol (29.74%) and p‐cymene (24.31%). Serial extractions with petroleum ether, ethyl acetate, ethanol, and water were performed on aerials parts of Origanum compactum. In these extracts, different chemical families were characterized: polyphenols (gallic acid equivalent 21.2 to 858.3 g/kg), tannins (catechin equivalent 12.4 to 510.3 g/kg), anthocyanins (cyanidin equivalent 0.38 to 5.63 mg/kg), and flavonoids (quercetin equivalent 14.5 to 54.7 g/kg). The samples (essential oil and extracts) were subjected to a screening for antioxidant (DPPH and ABTS assays) and antimalarial activities and against human breast cancer cells. The essential oil showed a higher antioxidant activity with an IC50= 2 ± 0.1 mg/L. Among the extracts, the aqueous extract had the highest antioxidant activity with an IC50= 4.8 ± 0.2 mg/L (DPPH assay). Concerning antimalarial activity, Origanum compactum essential oil and ethyl acetate extract showed the best results with an IC50 of 34 and 33 mg/mL, respectively. In addition, ethyl acetate extract (30 mg/L) and ethanol extract (56 mg/L) showed activity against human breast cancer cells (MCF7). The oregano essential oil was considered to be nontoxic. 相似文献
45.
Claude Descorme Patrick Gélin Michel Primet Christine Lécuyer 《Catalysis Letters》1996,41(3-4):133-138
The adsorption of NO at room temperature on a H-ZSM-5 catalyst exchanged with Pd(NH3)
4
2+
complex and activated in oxygen at 773 K has been examined by FTIR spectroscopy. After the oxidizing treatment, the Pd tetrammine complex decomposed into Pd(II) ions and/or Pd(II) hydroxyl complexes dispersed in the zeolite channels. The subsequent adsorption of NO at room temperature led to the reduction of Pd(II) to Pd(I) entities, resulting in the formation and adsorption of NO2 on H-ZSM-5. The Pd(I) entities were shown to adsorb NO and form mononitrosyl complexes dispersed in the zeolite porosity and characterized by a single infrared absorption band at 1881 cm–1. The Pd(I) mononitrosyl complex was shown to reversibly coordinate water and NO2 molecules. The resulting nitrosyl complex was characterized by a single NO vibration band at 1836 cm–1. 相似文献
46.
47.
Jean Claude Assaf Andr El Khoury Ali Chokr Nicolas Louka Ali Atoui 《International Journal of Dairy Technology》2019,72(2):248-256
This study aimed to develop a new method for detoxification of milk from aflatoxin M1 (AFM1) by using Lactobacillus rhamnosus GG biofilm. After inoculation of milk contaminated with AFM1 into L. rhamnosus GG biofilm, the unbound AFM1 was extracted and quantified by HPLC. The stability of the formed AFM1/biofilm complex using different AFM1 contamination levels of milk was also studied. We found that the percentages of bound AFM1 by L. rhamnosus GG biofilm reached up to 60.74%. While no significant difference in milk proteins content was observed after AFM1 binding, some changes in total dry matter and fat content were noticed. 相似文献
48.
Muoz-Lpez Cesar Nadem Daz-Silvestre Sergio Telles-Padilla J. Guadalupe Rivera-Vallejo Claudia St Thomas Claude Jimnez-Regalado Enrique 《Polymer Bulletin》2020,77(5):2539-2555
Polymer Bulletin - Preparation of associating multiblock copolymer electrolytes mediated by radical addition–fragmentation chain transfer (RAFT) technique has been evaluated and reported in... 相似文献
49.
Nooshin Araghipour Jennifer Colineau Alex Koot Wies Akkermans Jose Manuel Moreno Rojas Jonathan Beauchamp Armin Wisthaler Tilmann D. Märk Gerard Downey Claude Guillou Luisa Mannina Saskia van Ruth 《Food chemistry》2008
The volatile compositions of 192 olive oil samples from five different European countries were investigated by PTR-MS sample headspace analysis. The mass spectra of all samples showed many masses with high abundances, indicating the complex VOC composition of olive oil. Three different PLS-DA models were fitted to the data to classify samples into ‘country’, ‘region’ and ‘district’ of origin, respectively. Correct classification rates were assessed by cross-validation. The first fitted model produced an 86% success rate in classifying the samples into their country of origin. The second model, which was fitted to the Italian oils only, also demonstrated satisfactory results, with 74% of samples successfully classified into region of origin. The third model, classifying the Italian samples into district of origin, yielded a success rate of only 52%. This lower success rate might be due to either the small class set, or to genuine similarities between olive oil VOC compositions on this tight scale. 相似文献
50.
Croizé L Mondelain D Camy-Peyret C Delmotte M Schmidt M 《The Review of scientific instruments》2008,79(4):043101
We have developed a tunable diode laser spectrometer, called SIMCO (spectrometer for isotopic measurements of CO(2)), for determining the concentrations of (12)CO(2) and (13)CO(2) in atmospheric air, from which the total concentration of CO(2) and the isotopic composition (expressed in delta units) delta(13)CO(2) are calculated. The two concentrations are measured using a pair of lines around 2290.1 cm(-1), by fitting a line profile model, taking into account the confinement narrowing effect to achieve a better accuracy. Using the Allan variance, we have demonstrated (for an integration time of 25 s) a precision of 0.1 ppmv for the total CO(2) concentration and of 0.3[per thousand] for delta(13)CO(2). The performances on atmospheric air have been tested during a 3 days campaign by comparing the SIMCO instrument with a gas chromatograph (GC) for the measurement of the total CO(2) concentration and with an isotopic ratio mass spectrometer (MS) for the isotopic composition. The CO(2) concentration measurements of SIMCO are in very good agreement with the GC data with a mean difference of Delta(CO(2))=0.16+/-1.20 ppmv for a comparison period of 45 h and the linearity of the concentration between the two instruments is also very good (slope of correlation: 0.9996+/-0.0003) over the range between 380 and 415 ppmv. For delta(13)CO(2), the comparison with the MS data shows a larger mean difference of Delta(delta(13)CO(2))=(-1.9+/-1.2)[per thousand], which could be partly related to small residual fluctuations of the overall SIMCO instrument response. 相似文献