全文获取类型
收费全文 | 1342篇 |
免费 | 74篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 36篇 |
化学工业 | 254篇 |
金属工艺 | 39篇 |
机械仪表 | 20篇 |
建筑科学 | 35篇 |
矿业工程 | 4篇 |
能源动力 | 44篇 |
轻工业 | 125篇 |
水利工程 | 14篇 |
石油天然气 | 6篇 |
无线电 | 147篇 |
一般工业技术 | 207篇 |
冶金工业 | 270篇 |
原子能技术 | 7篇 |
自动化技术 | 212篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 22篇 |
2021年 | 35篇 |
2020年 | 18篇 |
2019年 | 42篇 |
2018年 | 43篇 |
2017年 | 34篇 |
2016年 | 50篇 |
2015年 | 31篇 |
2014年 | 61篇 |
2013年 | 85篇 |
2012年 | 61篇 |
2011年 | 64篇 |
2010年 | 65篇 |
2009年 | 45篇 |
2008年 | 57篇 |
2007年 | 63篇 |
2006年 | 49篇 |
2005年 | 26篇 |
2004年 | 32篇 |
2003年 | 31篇 |
2002年 | 39篇 |
2001年 | 38篇 |
2000年 | 22篇 |
1999年 | 31篇 |
1998年 | 73篇 |
1997年 | 45篇 |
1996年 | 26篇 |
1995年 | 26篇 |
1994年 | 22篇 |
1993年 | 20篇 |
1992年 | 16篇 |
1991年 | 11篇 |
1990年 | 7篇 |
1989年 | 14篇 |
1988年 | 14篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 6篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1977年 | 6篇 |
1976年 | 19篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有1420条查询结果,搜索用时 0 毫秒
61.
Tugrul U. Daim Donggyu Lim Fredy A. Gomez Justus Schwarz Stevan Jovanovic 《国际可持续能源杂志》2014,33(1):1-15
The transition from traditional energy sources to renewable has gained popularity and acceptance in recent years. This has been driven mainly by the current level of pollution, global warming, decommission of old nuclear power plants and the increasing cost of conventional energy sources. Nevertheless, one of the many steps to overcome is the seasonality or intermittency of renewable energy sources such as wind power. In recent years, new technologies have come up to address this problem, so the energy can be stored for future purposes. This paper analyses these energy storage alternatives for a specific case in the Columbia River Gorge for wind power. A hierarchical decision model is developed with criteria including political, social, environmental, technical and economical. The main conclusions highlight that the economical and technical criteria are among the most important ones for decision-makers. 相似文献
62.
Ismael Gomez Vuk Marojevic Antoni Gelonch 《Analog Integrated Circuits and Signal Processing》2011,69(2-3):153-160
Software-defined radio (SDR) permits dynamic switches of the employed radio access technology (RAT), over-the-air (OTA) software updates, software and hardware reuse. This extended flexibility comes at the price of a higher computing complexity and, in particular, the energy consumption at the receiver. The analysis of the computational profile of signal processing algorithms is of great importance in SDR for understanding the implication on the energy consumption. Several signal processing algorithms show a different profile as a function of the signal quality perceived at the receiver antenna. Therefore, power control policies have an implication on the computational performance of SDR receivers. Understanding the behaviour of these algorithms allows trading transmitted power against receiver energy consumption. This paper presents a model for characterizing the computational profile of Turbo and LDPC decoders and demonstrates is applicability in existing power control strategies. 相似文献
63.
Garcia Hector A.; Kelley Lance P.; Rentz Timothy O.; Lee Shuko 《Canadian Metallurgical Quarterly》2011,8(1):1
Cognitive–behavioral therapies (CBTs) can be effective treatments for posttraumatic stress disorder (PTSD) but their effectiveness is limited by high rates of premature dropout. Few studies have compared pretreatment characteristics of treatment completers and dropouts, and only one has examined these factors in Operations Iraqi Freedom and Enduring Freedom (OIF/OEF) Veterans. This study analyzed archival clinical data from 117 OEF/OIF Veterans evaluated and treated through a Veterans Affairs PTSD clinic. High numbers dropped out of treatment (68%). Treatment dropouts (n = 79) and completers (n = 38) differed significantly on Minnesota Multiphasic Personality Inventory-2 (MMPI-2) scales, PTSD symptom severity, and age. Regression analyses identified one MMPI-2 scale, TRT (negative treatment indicators), and age as unique but modest predictors of dropout. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
64.
65.
Transient Electronics: Thermally Triggered Degradation of Transient Electronic Devices (Adv. Mater. 25/2015) 下载免费PDF全文
66.
Syed Jafar Mehdi Hector Rosas-Hernandez Elvis Cuevas Susan M. Lantz Steven W. Barger Sumit Sarkar Merle G. Paule Syed F. Ali Syed Z. Imam 《International journal of molecular sciences》2016,17(9)
Currently, the lack of new drug candidates for the treatment of major neurological disorders such as Parkinson’s disease has intensified the search for drugs that can be repurposed or repositioned for such treatment. Typically, the search focuses on drugs that have been approved and are used clinically for other indications. Kinase inhibitors represent a family of popular molecules for the treatment and prevention of various cancers, and have emerged as strong candidates for such repurposing because numerous serine/threonine and tyrosine kinases have been implicated in the pathobiology of Parkinson’s disease. This review focuses on various kinase-dependent pathways associated with the expression of Parkinson’s disease pathology, and evaluates how inhibitors of these pathways might play a major role as effective therapeutic molecules. 相似文献
67.
Taller Hector Barroso 《世界建筑导报》2019,(4)
<正>在墨西哥Valle de Bravo一处茂密的丛林中,五栋假日住宅散布于此。它们顺应着场地的环境,在松树林与风的回声中静静屹立。五栋住宅采用完全相同的内部结构,其内部六个功能区相互连接围合出中央天井。该中庭享有良好的视野,静谧的氛围,和亲密的舒适感。位于北侧的建筑内部空间相对私密,而南侧则向自然充分开放。低层坐落着客厅,餐厅,厨房和一间融入外部露台、中庭和花园的卧室。顶层三间卧室面向松树林迎接美丽的自然景观。建筑材料源自于当地的砖,木和泥土。 相似文献
68.
Griselda Castruita-de León Claudia Y. Yeverino-Miranda Angel de J. Montes-Luna Hector Iván Meléndez-Ortiz German Alvarado-Tenorio Luis Alfonso García-Cerda 《应用聚合物科学杂志》2020,137(3):48286
Flat mixed matrix membranes (MMMs) comprising polysulfone and clinoptilolite-type natural zeolite were prepared by casting. Zeolite was modified with three alkylamines: ethanolamine (EA), bis(2-hydroxypropyl)amine (BHPA), and polyethylenimine (PEI) by the impregnation method. Impregnated zeolite samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and N2 adsorption–desorption. The alkylamine loading extent determined by thermogravimetric analysis was 5.2, 4.8, and 8.5% for EA, BHPA, and PEI, respectively. Analyses of MMMs showed that the incorporation of impregnated zeolite affected the glass-transition temperature (Tg) and mixed-gas transport properties. In this regard, a decreasing trend of the Tg values from 185.5 °C for the polymeric membrane up to 176.6 °C for Clino-EA-based MMM was recorded. In addition, the gas separation performance was evaluated at two different feed pressures. At 50 psi, MMMs showed an enhancement up to 30% on the CO2 permeability (22.79 Barrer) and 55% on the CO2/CH4 selectivity (45.78) in comparison with the polymeric membrane (CO2 permeability 17.34 Barrer; CO2/CH4 selectivity 29.38). These values varied depending on the alkylamine, BHPA being the most selective. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48286. 相似文献
69.
Silvia Gomez Joop A. Peters Jan C. van der Waal Wuzong Zhou Thomas Maschmeyer 《Catalysis Letters》2002,82(1-2):1-5
Platinum particles (<1.5 nm) have been shown to behave as bases in their interaction with -alumina. FTIR spectra of adsorbed pyridine probe molecules showed that the acid strength of the -alumina was decreased by the presence of (<1.5 nm) Pt particles. Ammonium chloride treatment converts the primary Pt clusters to H
x
Pt
y
Cl
z
intermediates that de-anchor from the support. Consequently, agglomeration to 8 nm Pt particles was observed following treatment in hydrogen at a relatively mild temperature. For the treated catalyst the IR data of absorbed pyridine show a 3 cm-1 increase relative to the original Pt/-Al2O3 catalyst, indicating a strengthening of the acidity. Changes in the Pt particle size were confirmed by FTIR spectroscopy of CO absorbed onto the Pt particles before and after treatment. Consecutive CO and pyridine probe adsorption demonstrated the electronic interplay between the Pt particles and the support. Pyridine adsorption onto the -alumina support of a Pt/Al2O3 catalyst pre-dosed with CO produces a nearly 40 cm-1 lowering of the CO peak position, indicative of CO bond weakening. In the case of CO adsorbed onto a catalyst pre-dosed with pyridine, a shift in the pyridine IR spectrum was only observed from the original highly dispersed catalyst. 相似文献
70.
A. Ureña J. M. Gomez De Salazar J. Quiñones S. Merino J. Martin 《Journal of Materials Science》1996,31(3):807-817
Diffusion bonds have been produced between sheets of an Al-Li-Cu-Mg-Zr alloy using aluminium-4% copper vapour deposited metallic interlayers. Microstructural changes occurred both in the parent alloy and in the bond interface after diffusion bonding cycles and post-bonding heat treatments were analysed. Different metallographic techniques (light microscopy, scanning and transmission electron microscopy) have been used. Diffusion bonding trials were carried out using the same alloy (AA8090), both in non-superplastic (T6) and superplastic conditions. Differences in their behaviours in relation to diffusion bonding were observed. 相似文献