全文获取类型
收费全文 | 1078篇 |
免费 | 58篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 361篇 |
金属工艺 | 8篇 |
机械仪表 | 9篇 |
建筑科学 | 39篇 |
矿业工程 | 1篇 |
能源动力 | 20篇 |
轻工业 | 207篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 70篇 |
一般工业技术 | 172篇 |
冶金工业 | 81篇 |
原子能技术 | 6篇 |
自动化技术 | 147篇 |
出版年
2024年 | 1篇 |
2023年 | 18篇 |
2022年 | 42篇 |
2021年 | 57篇 |
2020年 | 16篇 |
2019年 | 24篇 |
2018年 | 32篇 |
2017年 | 23篇 |
2016年 | 31篇 |
2015年 | 18篇 |
2014年 | 45篇 |
2013年 | 65篇 |
2012年 | 64篇 |
2011年 | 88篇 |
2010年 | 70篇 |
2009年 | 70篇 |
2008年 | 61篇 |
2007年 | 73篇 |
2006年 | 47篇 |
2005年 | 46篇 |
2004年 | 32篇 |
2003年 | 37篇 |
2002年 | 33篇 |
2001年 | 14篇 |
2000年 | 17篇 |
1999年 | 16篇 |
1998年 | 16篇 |
1997年 | 13篇 |
1996年 | 9篇 |
1995年 | 14篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1974年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1136条查询结果,搜索用时 15 毫秒
991.
Anaïs F. Poncet Olivier Grunewald Veronika Vaclavik Isabelle Meunier Isabelle Drumare Valrie Pelletier Batrice Bocquet Margarita G. Todorova Anne-Gaëlle Le Moing Aurore Devos Daniel F. Schorderet Florence Jobic Sabine Defoort-Dhellemmes Hlne Dollfus Vasily M. Smirnov Claire-Marie Dhaenens 《International journal of molecular sciences》2022,23(8)
992.
Sprague-Dawley rats were fed purified diets varying in both protein (20%) and lipid (11%) content for 28 d to verify the independent
and interactive effects of dietary proteins and lipids on serum and hepatic lipids, and on tissue lipoprotein lipase (LPL)
activity in both fasted and postprandial states. These diets consisted of either casein-menhaden oil, casein-coconut oil,
soy protein-menhaden oil (SPMO), soy protein-coconut oil, cod protein-menhaden oil, or cod protein-coconut oil. A randomized
3×2 factorial design was used. A significant protein-lipid interaction was seen on serum triglyceride levels: menhaden oil,
compared with coconut oil, induced a decrease in serum triglyceride levels when combined with soy protein but not when combined
with cod protein and casein. The lower serum triglyceride concentrations observed in the SPMO-fed rats could be the result
of decreased hepatic triglycerides when soy protein was compared with casein and when menhaden oil was compared with coconut
oil. Total LPL activity in the heart was higher in menhaden oil-fed rats than in coconut oil-fed rats in the postprandial
state. The higher LPL activity in the heart could, however, explain only 10% of the reduction of serum triglycerides, contributing
slightly to the lowering effects of SPMO diet on serum triglycerides. Therefore, the present results indicate that dietary
proteins can modulate the effects of fish oil on triglyceridemia in the rat, and that could be mainly related to specific
alterations in hepatic lipid concentrations. 相似文献
993.
Aïcha O. Cherif Mhamed Ben Messaouda Isabelle Pellerin Sadok Boukhchina Habib Kallel Claude Pepe 《Journal of the American Oil Chemists' Society》2013,90(5):675-686
Total hydrocarbon composition and content of whole peanuts from three Tunisian varieties of peanut (two cultivars: AraC (Virginia type), AraT (Valencia type) and a wild one: AraA) were investigated during maturation. The results show that 30 hydrocarbons were identified from the wild AraA species, while only 27 hydrocarbon were detected in the cultivar ones. The hydrocarbon fraction is essentially composed of squalene, n-alkenes especially nC14=, nC16=, nC18=, nC20= and nC22=, n-alkanes such as nC16, nC17, nC18, nC25, nC26 and nC27, and branched saturated hydrocarbon noted (HC1, HC2 and HC3). Among the hydrocarbon components, generally the wild variety AraA presents the highest content of phytochemical squalene during maturation, whereas a maximum was detected from cultivar AraT at 12 days after podding (815.45 mg/100 g of oil). At maturity, the maximum level is reached at about 346.74 mg/100 g of oil for AraA. During maturity, wild AraA is considered to be an excellent source of squalene like olive and pumpkin oil. 相似文献
994.
Treatment of odorous sulphur compounds by chemical scrubbing with hydrogen peroxide--stabilisation of the scrubbing solution 总被引:2,自引:0,他引:2
Charron I Couvert A Laplanche A Renner C Patria L Requieme B 《Environmental science & technology》2006,40(24):7881-7885
To slow down the hydrogen peroxide decomposition in basic aqueous conditions, the addition of stabilizers and co-stabilizers in the scrubbing solution was investigated. Results found with sodium silicate (Na2SiO3) were quite promising but several problems still remained. Based on these observations, this study focused on the research of a better stabilizer. Several ways were investigated: the use of silicate solutions employed in pulp industries, the addition of co-stabilizers to sodium silicate, or the use of an another stabilizer (the poly-alpha-hydroxyacrylic acid). Experiments revealed that the poly-alpha-hydroxyacrylic acid is the best stabilizing compound. 相似文献
995.
Lyudmyla V. Karabanova Gisele Boiteux Gerard Seytre Isabelle Stevenson Andrew W. Lloyd Sergey V. Mikhalovsky Mikle Helias Lyudmyla M. Sergeeva Elena D. Lutsyk Anna Svyatyna 《Polymer Engineering and Science》2008,48(3):588-597
The thermal, dynamic mechanical analysis, morphology and mechanical properties of semi‐interpenetrating polymer networks based on crosslinked polyurethane (PU) and poly(2‐hydroxyethyl methacrylate) (PHEMA) synthesized by photopolymerization and by thermopolymerization have been investigated. The thermal analysis has evidenced the two glass temperature transitions in the semi‐IPNs and this is confirmed by the thermodynamic miscibility investigation of the systems. The Dynamic Mechanical Analysis spectra have shown that the phase separation is more significant in the thermopolymerized semi‐IPNs: the tan δ peaks of constituent polymers are more distinct and the minimum between the two peaks is deeper. The calculated segregation degree values of semi‐IPN's components are significantly higher for thermopolymerized semi‐IPNs, thereby the process of phase separation in the thermopolymerized semi‐IPNs is more developed. The structures of two series of samples investigated by SEM are completely different. The mechanical properties reflect these changes in structure of semi‐IPNs with increasing amount of PHEMA and with the changing of the method of synthesis. The results suggest that the studied semi‐IPNs are two‐phase systems with incomplete phase separation. The semi‐IPN samples with early stage of phase separation demonstrate higher mechanical characteristics. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers 相似文献
996.
García-Graells C Van Opstal I Vanmuysen SC Michiels CW 《International journal of food microbiology》2003,81(3):211-221
The inactivation of eight different bacteria comprising Escherichia coli LMM1010 and MG1655, respectively a pressure-resistant strain and the corresponding wild-type, Salmonella Typhimurium, Pseudomonas fluorescens, Staphylococcus aureus, Enterococcus faecalis, Listeria innocua and Lactobacillus plantarum, by high hydrostatic pressure in skim milk supplemented with the lactoperoxidase-hydrogen peroxide-thiocyanate (LP) system at naturally occurring concentration was studied. In the absence of pressure treatment, the LP system had either no effect, i.e. on S. Typhimurium and E. coli LMM1010, a growth inhibiting effect, i.e. on E. coli MG1655, L. innocua, S. aureus, L. plantarum and E. faecalis, or a bactericidal effect, i.e. on P. fluorescens. The presence of the LP system affected inactivation by high pressure in a cell density-dependent manner. At low cell concentration (10(6) cfu/ml), the LP system strongly increased high-pressure inactivation as measured immediately after pressure treatment of all bacteria except the pressure-resistant E. coli. At high cell density (10(9) cfu/ml), only inactivation of L. innocua, E. faecalis and L. plantarum were enhanced. For both E. coli strains, the fate of the bacteria during 24 h following pressure treatment was also studied. It was found that in the presence of the LP system, considerable further inactivation occurred in the first hours after pressure treatment. The potential of the LP system to improve the bactericidal efficiency of high-pressure treatment for food preservation is discussed. 相似文献
997.
Csar Omar Ramírez Quiroz George D. Spyropoulos Michael Salvador Loïc M. Roch Marvin Berlinghof Jos Darío Perea Karen Forberich Laura‐Isabelle Dion‐Bertrand Nadine J. Schrenker Andrej Classen Nicola Gasparini Ganna Chistiakova Mathias Mews Lars Korte Bernd Rech Ning Li Frank Hauke Erdmann Spiecker Tayebeh Ameri Steve Albrecht Gonzalo Abelln Salvador Len Tobias Unruh Andreas Hirsch Aln Aspuru‐Guzik Christoph J. Brabec 《Advanced functional materials》2019,29(40)
A multipurpose interconnection layer based on poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS), and d ‐sorbitol for monolithic perovskite/silicon tandem solar cells is introduced. The interconnection of independently processed silicon and perovskite subcells is a simple add‐on lamination step, alleviating common fabrication complexities of tandem devices. It is demonstrated experimentally and theoretically that PEDOT:PSS is an ideal building block for manipulating the mechanical and electrical functionality of the charge recombination layer by controlling the microstructure on the nano‐ and mesoscale. It is elucidated that the optimal functionality of the recombination layer relies on a gradient in the d ‐sorbitol dopant distribution that modulates the orientation of PEDOT across the PEDOT:PSS film. Using this modified PEDOT:PSS composite, a monolithic two‐terminal perovskite/silicon tandem solar cell with a steady‐state efficiency of 21.0%, a fill factor of 80.4%, and negligible open circuit voltage losses compared to single‐junction devices is shown. The versatility of this approach is further validated by presenting a laminated two‐terminal monolithic perovskite/organic tandem solar cell with 11.7% power conversion efficiency. It is envisioned that this lamination concept can be applied for the pairing of multiple photovoltaic and other thin film technologies, creating a universal platform that facilitates mass production of tandem devices with high efficiency. 相似文献
998.
Sizing and optimization of high throughput radio‐frequency data down link of earth observation satellites
下载免费PDF全文
![点击此处可从《International Journal of Satellite Communications and Networking》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Nicolas Jeannin Isabelle Dahman 《International Journal of Satellite Communications and Networking》2016,34(2):231-250
This paper analyses the sizing of networks of radio‐frequency ground stations operating at Ka band or above for the reception of data acquired by low earth orbit observation satellites. In particular, the way to account for the use of adaptive transmission schemes, to cope with the high propagation impairments in the troposphere is detailed. A solution to size optimally the ground stations and satellite memory, relying on propagation channel simulations, is also proposed. The resulting performances are assessed in a latter stage using simulated propagation time series. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
999.
Peretz Isabelle; Baba? Myriam; Lussier Isabelle; Hébert Sylvie; Gagnon Lise 《Canadian Metallurgical Quarterly》1995,49(2):211
Studied the degree of familiarity, the age of acquisition, and verbal associations with regard to 144 musical excerpts drawn from the repertory of tunes that is expected to be shared by all French-speaking Quebec university students. Human Ss: 60 normal male and female Canadian adults (aged 21–45 yrs) (university students) (Group 1). 60 normal male and female Canadian adults (aged 19–43 yrs) (university students) (Group 2). The excerpts were presented to all Ss in synthesized, monophonic recordings. Ss in Group 1 were asked to indicate their degree of familiarity with each excerpt and the age at which they learned the excerpt. Ss in Group 2 were asked to indicate whether the original tune was vocal or instrumental and to provide verbal associations for the excerpts. The degree of familiarity, developmental period of acquisition, frequency of verbal associations, and dominant verbal association were determined for each excerpt. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
1000.
There is ample evidence today in the stereotype threat literature that women and girls are influenced by gender-stereotyped expectations on standardized math tests. Despite its high relevance to education, this phenomenon has not received much attention in school settings. The present studies offer the 1st evidence to date indicating that middle school girls exhibit a performance deficit in quasi-ordinary classroom circumstances when they are simply led to believe that the task at hand measures mathematical skills. This deficit occurred in girls working alone or in mixed-gender groups (i.e., presence of regular classmates) but not in same-gender groups (i.e., presence of only same-gender classmates). Compared with the mixed-gender groups, the same-gender groups were also associated for girls in the stereotype threat condition with greater accessibility of positive role models (i.e., female classmates who excel in math), at the expense of both stereotypic in-group and out-group members (i.e., low-math-achievement girls and high-math-achievement boys). Finally, the greater accessibility of positive role models mediated the impact of the activated stereotype on girls' performance, exactly as one would expect from C. M. Steele's (1997) stereotype threat theory. Taken together, these findings clearly show that reducing stereotype threat in the classroom is a crucial challenge for both scientists and teachers. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献