全文获取类型
收费全文 | 968篇 |
免费 | 43篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 15篇 |
综合类 | 1篇 |
化学工业 | 376篇 |
金属工艺 | 27篇 |
机械仪表 | 21篇 |
建筑科学 | 33篇 |
矿业工程 | 3篇 |
能源动力 | 26篇 |
轻工业 | 140篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
武器工业 | 1篇 |
无线电 | 66篇 |
一般工业技术 | 168篇 |
冶金工业 | 15篇 |
原子能技术 | 8篇 |
自动化技术 | 112篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 66篇 |
2021年 | 80篇 |
2020年 | 22篇 |
2019年 | 26篇 |
2018年 | 27篇 |
2017年 | 26篇 |
2016年 | 44篇 |
2015年 | 29篇 |
2014年 | 43篇 |
2013年 | 72篇 |
2012年 | 63篇 |
2011年 | 64篇 |
2010年 | 43篇 |
2009年 | 42篇 |
2008年 | 42篇 |
2007年 | 36篇 |
2006年 | 27篇 |
2005年 | 26篇 |
2004年 | 26篇 |
2003年 | 16篇 |
2002年 | 24篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 12篇 |
1996年 | 15篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 11篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1971年 | 1篇 |
排序方式: 共有1015条查询结果,搜索用时 31 毫秒
71.
Jacek Słupski Jacek Achrem‐Achremowicz Zofia Lisiewska Anna Korus 《International Journal of Food Science & Technology》2010,45(8):1682-1688
The aim of this work was to evaluate the effect of processing on the amino acid content and protein quality of New Zealand spinach (Tetragonia tetragonioides Pall. Kuntze). In this research, fresh and cooked New Zealand spinach as well as two frozen products prepared for consumption, one obtained using the traditional method (blanching–freezing–storage–cooking) and the other a convenience food product obtained using a modified process (cooking–freezing–storage–defrosting and heating in a microwave oven), were analysed. Glutamic acid was the dominant amino acid in fresh New Zealand spinach, and the limiting amino acids were cystine and methionine. Technological and culinary processing caused a significant increase in amino acid content in 100 g of edible portion, with the exception of methionine and cystine in frozen products prepared for eating. Changes in amino acid content expressed in g/16 g of N (which corresponded to 100 g tissue protein) were not significant, with the exception of the lower glutamic acid content in the frozen product obtained using traditional processing method. 相似文献
72.
The paper deals with the determination of reliability of an elementary safety system which consists of two identical elements used simultaneously (hot reserve) whereas for correct system operation is enough when one out of it is good. The operation time is so short that is assumed it is of zero length. Knowing the reliability of element, reliability of system is found. 相似文献
73.
Rados?aw Bandomir Mariusz Krawczyk Jacek Namie?nik 《Journal of Automated Methods and Management in Chemistry》2005,2005(2):55-57
We present the results of a first stage of development work on a new type of analyzer for hydrogen and C1–C3 hydrocarbons concentration measurements in the lower explosive limit range, based on single pellistor sensor with artificial neural network data postprocessing. 相似文献
74.
A two-way circular consecutively connected system with multistate components (two-way circular CCSMC) consists of n cyclically ordered components e1,…,en, i.e. ei+1, succeeds e1, iε«ng l, …, n − 1ång;, e, succeeds en- Each component is capable of sending a signal in left-hand and right-hand directions. All components operate independently. The whole system is functioning if both left-hand and right-hand signals are received by each component. A recursive procedure evaluating the reliability of a two-way circular CCSMC is presented. 相似文献
75.
The experimental material was a myofibrillar preparation obtained from mechanically recovered poultry meat by the washing
and separation of fat and connective tissues. Changes occurring during frozen storage were investigated in the preparation
without and with the addition of the following substances: 2 g/kg carrageen, 2.5 g/kg sodium tripolyphosphate (TPP) mixture
and 80 g/kg polydextrose, and 3 g/kg enzymatic preparation (ACTIVA WM) containing microbial transglutaminase (MTG). Samples
with the addition of MTG were pre-incubated at the temperature of 7 ± 1 °C for 1, 3, 5, 24 h. All samples were stored at the
temperature of approx. −23 °C for 2, 30, 60, 90 days. The smallest change in protein solubility was observed in samples with
added TPP and polydextrose. Along with the extension of pre-incubation time of samples containing the enzyme a gradual decrease
was found in the amount of soluble protein. Also the results of the investigations obtained using the DSC technique showed
the most advantageous protective effect, i.e., causing the smallest decrease in enthalpy values of samples during freezer
storage, in case of the addition of TPP and polydextrose mixture. Analysis of thermal drip volume from gels showed that carrageen
was the most advantageous addition to the myofibrillar preparation. Moreover, a gradual increase was observed in the volume
of thermal drip along with the extension of pre-incubation time of the protein isolate with enzymatic preparation. Results
of gel texture testing indicated that the most advantageous effect on gel quality was found for ACTIVA applied in 3 and 5 h
pre-incubation with the myofibrils. Assuming that among the analyzed properties the most important were thermal drip and gel
texture, 3 g/kg MTG at pre-incubation time of 3 h was considered the most advantageous additive. 相似文献
76.
Corrosion processes in drinking water distribution systems have been investigated for years. This paper proves the existence of a layer of steady water surrounding and partly filling corrosion scale in corroded water pipes. It is expected that steady water may substantially influence the corrosion. The idea of steady water explains why longer retention times would lead to more turbid waters containing more suspended Fe oxides (hydroxides). During stagnation period stagnant water mixes partially with steady water and the compensation of ions' concentration as well as particle diffusion is observed. Steady water is rich in ions and has reductive properties causing quick disappearance of nitrates and unwanted ammonia formation. Ammonia in turn may be responsible for fast oxygen and chlorine decay in the distribution system due to nitrification. Nitrates may also undergo denitrification in steady water, i.e. they would support bacterial existence in the distribution system. Such an environment makes favourable conditions for sulphate reducing bacteria and in fact in all of the steady water samples we have detected sulphides. Moreover, our results have shown that considerable amounts of assimilable organic carbon (AOC) can be formed in the corroded distribution system. 相似文献
77.
Janicka M Kot-Wasik A Kot J Namieśnik J 《International journal of molecular sciences》2010,11(11):4631-4659
Isoprostanes (IsoPs) are key biomarkers for investigating the role of free radical generation in the pathogenesis of human disorders. To solve IsoPs-related problems with regard to isoprostanes, analytical tools are required. This paper reviews the problems and trends in this field focusing on the methodology for assaying biomarkers in exhaled breath condensate (EBC) samples. A large amount of work has been done in the qualitative and quantitative analysis of IsoPs, but a standardized method has yet to emerge. The methodologies described differ, either in the sample preparation steps or in the detection techniques, or both. Requiring a number of chromatographic steps, the relevant extraction and purification procedures are often critical and time-consuming, and they lead to a substantial loss of target compounds. Recent data show that EBC is a promising non-invasive tool for the evaluation of different diseases. Two main analytical approaches have been adopted for IsoPs measurement: immunological methods and mass spectrometry. The methodologies for the extraction, purification and analysis of IsoPs in EBC samples are presented. 相似文献
78.
Marcin Pastorczak Michael Wübbenhorst Gustavo Dominguez-Espinosa Lidia Okrasa Marek Pyda Marcin Kozanecki Slawomir Kadlubowski Piotr Ulanski Janusz M. Rosiak Jacek Ulanski 《Polymer》2012,53(1):161-168
The phase transition observed by various methods in poly(vinyl methyl ether)/water systems at around 18 °C has been assigned by some investigators to the pre-melting of water and by others to a glass transition of the polymer. In this study, broadband dielectric spectroscopy and temperature modulated differential scanning calorimetry were used to identify this transition in radiationally crosslinked poly(vinyl methyl ether) hydrogels, as well as to analyse sub-zero relaxation processes in such a three-phase (polymer/ice/liquid water) system. The process at 18 °C was related to the pre-melting of water induced by the segmental motions of the polymer; however, it was seen to be one transition due to the cooperative motions of both compounds. The atypical (two regimes) temperature dependence of the segmental motion process was observed and was related to confinement of the polymer chains between ice clusters below approximately ?24 °C; furthermore, the main dielectric process of hexagonal ice was identified and a Maxwell-Wagner effect was observed. 相似文献
79.
ABSTRACT The deformations and drying-induced stresses in a saturated porous plate insulated on one side and dried convectively on the others were analysedPlate material is assumed to be elastic and viscoelastic. A rigorous solution of the problem is presented using Laplace transformations and the method of variable separation. The results are presented in the form of a series resulting from the solution of a Sturm-Liouville problem. The shrinkage stresses in the plate are caused by non-uniform distribution of the moisture content. The thermal stresses are not included as the consideration were confined to only constant rate drying period. 相似文献
80.