全文获取类型
收费全文 | 1854篇 |
免费 | 109篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 29篇 |
化学工业 | 457篇 |
金属工艺 | 32篇 |
机械仪表 | 40篇 |
建筑科学 | 71篇 |
矿业工程 | 2篇 |
能源动力 | 98篇 |
轻工业 | 223篇 |
水利工程 | 17篇 |
石油天然气 | 2篇 |
无线电 | 157篇 |
一般工业技术 | 352篇 |
冶金工业 | 76篇 |
原子能技术 | 4篇 |
自动化技术 | 407篇 |
出版年
2024年 | 7篇 |
2023年 | 24篇 |
2022年 | 51篇 |
2021年 | 69篇 |
2020年 | 29篇 |
2019年 | 55篇 |
2018年 | 54篇 |
2017年 | 64篇 |
2016年 | 70篇 |
2015年 | 53篇 |
2014年 | 96篇 |
2013年 | 136篇 |
2012年 | 143篇 |
2011年 | 159篇 |
2010年 | 110篇 |
2009年 | 135篇 |
2008年 | 129篇 |
2007年 | 97篇 |
2006年 | 72篇 |
2005年 | 47篇 |
2004年 | 64篇 |
2003年 | 45篇 |
2002年 | 42篇 |
2001年 | 25篇 |
2000年 | 15篇 |
1999年 | 22篇 |
1998年 | 24篇 |
1997年 | 31篇 |
1996年 | 23篇 |
1995年 | 17篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有1967条查询结果,搜索用时 15 毫秒
51.
Biodegradable Ethylene‐Bis(Propyl)Disulfide‐Based Periodic Mesoporous Organosilica Nanorods and Nanospheres for Efficient In‐Vitro Drug Delivery 下载免费PDF全文
52.
53.
(4‐Ethylphenyl)‐3,5‐ditertiarybutyl‐4‐hydroxybenzylamine, 1‐phenyl‐4‐(3,5‐ditertiarybutyl‐4‐hydroxybenzyl)piperazine, and 1‐(3,5‐ditertiarybutyl‐4‐hydroxybenzyl)piperidine were synthesized and characterized, and their performance in polypropylene copolymer (PPCP) was tested by multiple extrusions in a Brabender plasticorder. The thermooxidative stability of PPCP was assessed by the measurement of oxidative induction time at 200 ± 1°C, and the thermal stability was assessed by observation of the change in the melt flow rate. A comparative study of the synthesized antioxidants with the commercially available antioxidant 2,6‐ditertiarybutyl‐4‐methylphenol was made. The presence of phenolic and amino groups influenced the performance of the antioxidants. The performance of the antioxidants influenced the thermal stability of the PPCP. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1097–1103, 2004 相似文献
54.
Chateau Marie-Elise Galet Laurence Soudais Yannick Fages Jacques 《Journal of surfactants and detergents》2004,7(4):355-362
A new test was developed to assess the efficiency of no-wiping hard-surface cleaning. The test allows cleaner comparisons
according to their ability to remove greasy soils. The chosen approach minimizes the mechanical forces applied while cleaning
so that the interactions between a detergent solution and the soil to be removed can be characterized. For this, immersion
cleaning was chosen, with coated stainless steel as substrate and pigmented oils as the model soil. Several parameters were
studied in defined ranges using the Experimental Design method and systematic comparisons. The test shows high reliability
on degreasing assessments and is there-fore especially suited to optimization of nonionic surfactant mixes. The originality
of the test lies in the possibility of keeping a visual trace of the cleaned substrate appearance by imprinting it on a piece
of paper. The validation of the test leads to corroboration of several practical observations. Temperature and agitation play
a major role in cleaning efficiency. Detergent solution concentration is a more relevant parameter than pH. Sodium carbonate
is shown to have a higher buffering effect than pentahydrated sodium metasilicate. The test is easy to set up, highly sensitive,
and can be adapted to solve the problems encountered by formulators of detergent cleaners, such as screening the best ethoxylated
fatty alcohol mix for better degreasing properties. 相似文献
55.
We have studied the preparation of a new class of epoxy thermosets from diglycidyl ether of bisphenol A (DGEBA) modified with an amphiphilic star polymer (SP), initiated either by 1-methyl imidazole or ytterbium triflate, anionic and cationic initiators, respectively. The curing process has been characterized by means of DSC, FTIR and rheology. The last technique allowed us to monitor the shrinkage during curing. DMTA provided valuable information about the transitions of the materials, as well as their modulus in the rubbery state. Cationic systems produce monomodal tan δ relaxations, whereas anionics presented a shoulder in this peak. By means of electron microscopy we could observe phase separation in the case of cationically initiated systems while in the anionic initiated materials zones with different electronic densities were appreciated. Finally, Young’s modulus and hardness of the materials were determined by nanoinentation. 相似文献
56.
Helga Simon-Molas Xavier Vallv-Martínez Irene Caldera-Quevedo Pere Fontova Claudia Arnedo-Pac Anna Vidal-Alabr Esther Castao urea Navarro-Sabat Núria Lloberas Ramon Bartrons Anna Manzano 《International journal of molecular sciences》2021,22(14)
The glycolytic modulator TP53-Inducible Glycolysis and Apoptosis Regulator (TIGAR) is overexpressed in several types of cancer and has a role in metabolic rewiring during tumor development. However, little is known about the role of this enzyme in proliferative tissues under physiological conditions. In the current work, we analysed the role of TIGAR in primary human lymphocytes stimulated with the mitotic agent Concanavalin A (ConA). We found that TIGAR expression was induced in stimulated lymphocytes through the PI3K/AKT pathway, since Akti-1/2 and LY294002 inhibitors prevented the upregulation of TIGAR in response to ConA. In addition, suppression of TIGAR expression by siRNA decreased the levels of the proliferative marker PCNA and increased cellular ROS levels. In this model, TIGAR was found to support the activity of glucose 6-phosphate dehydrogenase (G6PDH), the first enzyme of the pentose phosphate pathway (PPP), since the inhibition of TIGAR reduced G6PDH activity and increased autophagy. In conclusion, we demonstrate here that TIGAR is upregulated in stimulated human lymphocytes through the PI3K/AKT signaling pathway, which contributes to the redirection of the carbon flux to the PPP. 相似文献
57.
Impact of oxygen transport properties on the kinetic modeling of polypropylene thermal oxidation. II. Effect of oxygen diffusivity 下载免费PDF全文
Alexandre François‐Heude Emmanuel Richaud Alain Guinault Eric Desnoux Xavier Colin 《应用聚合物科学杂志》2015,132(6)
The kinetic model, established in a previous article (François‐Heude et al., J. Appl. Polym. Sci., in press) to predict the homogeneous oxidation in iPP films typically thinner than 100 µm, is now extended to simulate the oxidation profiles in thicker plates by coupling the oxygen diffusion and its consumption by the chemical reactions. In this perspective, oxygen transport properties (namely oxygen solubility, diffusivity, and permeability) are measured by permeametry on a reference iPP. These values are compared with an exhaustive compilation of literature data to evaluate their variability among the whole iPP family, which one has been reasonably ascribed to initial differences in polymer morphology, but also to evaluate their consistency, especially their temperature dependence between 20 and 140°C. Failing to simulate oxidation profiles, the kinetic model is then used as an inverse resolution method for estimating more satisfactory values of oxygen transport properties. It is thus evidenced that the crystallinity changes induced by thermal oxidation largely explains the dramatic decrease in oxygen penetration toward the sample core just after the induction period. A strategy aimed for introducing the relationship between the polymer crystalline morphology and oxygen transport properties into the kinetic model is given in the graphical abstract, although the effect of polymer polarity remains to be established prior to this implementation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41562. 相似文献
58.
The anionic curing initiated by 1‐methyl imidazole of diglycidyl ether of bisphenol A with a hyperbranched polymer (HBP) containing long aliphatic chains in the structure were studied. The hydroxyl groups present as chain ends in the HBP structure played an important role in the curing kinetics, as demonstrated by differential scanning calorimetry, Fourier transform infrared spectroscopy and rheological studies. Properties such as shrinkage on curing and thermomechanical characteristics were also investigated. The structure of the HBP, which contains long aliphatic chains and reactive hydroxyl groups as chain ends, flexibilizes the network significantly, improving the impact resistance without notably affecting either the glass transition temperature or the microhardness of the modified thermosets. Copyright © 2012 Society of Chemical Industry 相似文献
59.
Wei Chen Jian Liu Flore Brue Frédéric Skoczylas C.A. Davy Xavier Bourbon Jean Talandier 《Cement and Concrete Research》2012,42(7):1001-1013
This experimental study aims at identifying the water retention properties of two industrial concretes to be used for long term underground nuclear waste storage structures. Together with water retention, gas transfer properties are identified at varying water saturation level, i.e. relative gas permeability is assessed directly as a function of water saturation level Sw. The influence of the initial de-sorption path and of the subsequent re-saturation are analysed both in terms of water retention and gas transfer properties. Also, the influence of concrete microstructure upon water retention and relative gas permeability is assessed, using porosity measurements, analysis of the BET theory from water retention properties, and MIP. Finally, a single relative gas permeability curve is proposed for each concrete, based on Van Genuchten–Mualem's statistical model, to be used for continuous modelling approaches of concrete structures, both during drying and imbibition. 相似文献
60.
Renan Felicio dos Reis Joao Sergio Cordeiro Xavier Font Cali Laguna Achon 《Drying Technology》2020,38(10):1247-1260
AbstractSewage treatment can be classified into three phases: liquid, gaseous, and solid. Treatment of solids is performed in several steps, and the greatest difficulty in removing water from sewage sludge is due to the bound water present in the sludge. Thus, biodrying, a drying method that can be classified as biological, has been recently applied to treat this type of waste. This review paper aims to report and compile data from 49 biodrying assays of sewage sludge found in the literature (through the present, 2019) into one synthesis table, to discuss and compare the numerous variables found in these papers and their implications for biodrying, and to suggest possibilities for future research. This paper additionally intends to improve knowledge of biodrying and to consequently contribute to the monitoring and understanding of the process. 相似文献