全文获取类型
收费全文 | 804篇 |
免费 | 76篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 413篇 |
金属工艺 | 16篇 |
机械仪表 | 4篇 |
建筑科学 | 24篇 |
矿业工程 | 3篇 |
能源动力 | 19篇 |
轻工业 | 154篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 52篇 |
一般工业技术 | 79篇 |
冶金工业 | 53篇 |
原子能技术 | 2篇 |
自动化技术 | 55篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 86篇 |
2021年 | 141篇 |
2020年 | 47篇 |
2019年 | 38篇 |
2018年 | 33篇 |
2017年 | 35篇 |
2016年 | 46篇 |
2015年 | 31篇 |
2014年 | 34篇 |
2013年 | 53篇 |
2012年 | 53篇 |
2011年 | 57篇 |
2010年 | 34篇 |
2009年 | 22篇 |
2008年 | 23篇 |
2007年 | 24篇 |
2006年 | 20篇 |
2005年 | 11篇 |
2004年 | 10篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有881条查询结果,搜索用时 203 毫秒
61.
62.
AbstractBeech wood has a high frequency of defects such as red heartwood, reaction wood (tension wood). For the experimental measurements four logs without visible defects like red heartwood, which can noticeably affects the measurements' results were qualified. The drying medium temperature in the first phase of the process before the moisture content of the specimens fell below the FSP was maintained at 45?°C. Then, the temperature was gradually increased to the maximum value 65?°C. The results showed that different initial wood moisture content does not affect to final value of tension and normal wood. The colorimetric parameter L* was much higher for tension wood. After steaming, there were greater differences in the colorimetric parameters, respectively, a* and b*. After drying the difference of all colorimetric parameters between tension and normal wood was significantly less. The color changes were only noticed in the surface layers of specimens. Differences were small, and thus, the impact of the tension wood on the color changes was not confirmed. However, since the lightness of tension wood plays a key role for its visual detection, it may be adequate to only measure the lightness parameter (L*). 相似文献
63.
64.
65.
Nina Krako Jakovljevic Kasja Pavlovic Aleksandra Jotic Katarina Lalic Milica Stoiljkovic Ljiljana Lukic Tanja Milicic Marija Macesic Jelena Stanarcic Gajovic Nebojsa M. Lalic 《International journal of molecular sciences》2021,22(12)
Type 2 diabetes (T2D), one of the most prevalent noncommunicable diseases, is often preceded by insulin resistance (IR), which underlies the inability of tissues to respond to insulin and leads to disturbed metabolic homeostasis. Mitochondria, as a central player in the cellular energy metabolism, are involved in the mechanisms of IR and T2D. Mitochondrial function is affected by insulin resistance in different tissues, among which skeletal muscle and liver have the highest impact on whole-body glucose homeostasis. This review focuses on human studies that assess mitochondrial function in liver, muscle and blood cells in the context of T2D. Furthermore, different interventions targeting mitochondria in IR and T2D are listed, with a selection of studies using respirometry as a measure of mitochondrial function, for better data comparison. Altogether, mitochondrial respiratory capacity appears to be a metabolic indicator since it decreases as the disease progresses but increases after lifestyle (exercise) and pharmacological interventions, together with the improvement in metabolic health. Finally, novel therapeutics developed to target mitochondria have potential for a more integrative therapeutic approach, treating both causative and secondary defects of diabetes. 相似文献
66.
Smith Dylan; Loewenstein George; Jepson Christopher; Jankovich Aleksandra; Feldman Harold; Ubel Peter 《Canadian Metallurgical Quarterly》2008,27(5):653
Objective: People tend to overestimate the impact that future events will have on their quality of life. In the case of a medical treatment like kidney transplant, this should result in biased predictions--overestimates of how much the transplant will benefit quality of life. The authors surveyed kidney transplant patients, both before and after transplant, to test whether they would overestimate the benefits of a successful transplant for their quality of life. Design: The authors interviewed 307 patients on a waiting list for cadaveric renal or renal-pancreatic transplant, and 195 patients one year after a successful transplant. A sub sample of patients were interviewed both before and after transplant. Main Outcome Measures: The survey included measures of quality of life, both in terms of an overall estimate (0-100), and across sub domains, including health, employment, and travel. Results: Cross-sectional results suggested that overall quality of life improved after transplant, but the predictions of pretransplant patients overestimated the magnitude of the improvement (p 相似文献
67.
68.
Lukasz Drewniak Robert Stasiuk Witold Uhrynowski Aleksandra Sklodowska 《International journal of molecular sciences》2015,16(7):14409-14427
The purpose of this study was a detailed characterization of Shewanella sp. O23S, a strain involved in arsenic transformation in ancient gold mine waters contaminated with arsenic and other heavy metals. Physiological analysis of Shewanella sp. O23S showed that it is a facultative anaerobe, capable of growth using arsenate, thiosulfate, nitrate, iron or manganite as a terminal electron acceptor, and lactate or citrate as an electron donor. The strain can grow under anaerobic conditions and utilize arsenate in the respiratory process in a broad range of temperatures (10–37 °C), pH (4–8), salinity (0%–2%), and the presence of heavy metals (Cd, Co, Cr, Cu, Mn, Mo, Se, V and Zn). Under reductive conditions this strain can simultaneously use arsenate and thiosulfate as electron acceptors and produce yellow arsenic (III) sulfide (As2S3) precipitate. Simulation of As-removal from water containing arsenate (2.5 mM) and thiosulfate (5 mM) showed 82.5% efficiency after 21 days of incubation at room temperature. Based on the obtained results, we have proposed a model of a microbially mediated system for self-cleaning of mine waters contaminated with arsenic, in which Shewanella sp. O23S is the main driving agent. 相似文献
69.
70.
Dynamic experimental simulation of hydrogen oriented underground gasification of lignite 总被引:2,自引:0,他引:2
Krzysztof Stańczyk Krzysztof Kapusta Marian Wiatowski Jerzy ?wi?drowski Andrzej Kotyrba Jan Rogut 《Fuel》2010,89(11):3307-3314
The main goal of the study presented in the paper was to experimentally demonstrate the feasibility of lignite gasification to hydrogen-rich gas under the underground conditions simulated in the ex situ reactor. The in situ gasification conditions were simulated both in respect to the coal seam and the surrounding stratum. In the 54-h experiment the process of lignite gasification with oxygen and steam as gasifying medium was tested. The experiment was initially divided into three stages: the ignition stage, the oxygen stage and the steam stage.The gas produced in the steam gasification stage was characterized by the calorific value of 7.8 MJ/m3 and average hydrogen content of 46.3 vol.%. Unfortunately a rapid decrease in the temperature levels and in the amount of produced gas proved that the tested lignite of 53 vol.% moisture content was not suitable for steam gasification. A great amount of thermal energy was consumed for water evaporation which led to a considerable heat loss. An addition of stoichiometric amount of water in the system by adding steam caused the seam to extinguish. Thus only oxygen could be used as the gasifying medium in the gasification of the tested lignite. The average calorific value of gas produced in the stable operation during oxygen gasification stage equaled 5.2 MJ/m3 with the average gas production rate of 16.0 m3/h and the average hydrogen content in the produced gas of 26.4 vol.%. 相似文献