全文获取类型
收费全文 | 1085篇 |
免费 | 22篇 |
专业分类
电工技术 | 19篇 |
化学工业 | 238篇 |
金属工艺 | 27篇 |
机械仪表 | 22篇 |
建筑科学 | 57篇 |
矿业工程 | 23篇 |
能源动力 | 14篇 |
轻工业 | 111篇 |
水利工程 | 21篇 |
石油天然气 | 3篇 |
无线电 | 75篇 |
一般工业技术 | 189篇 |
冶金工业 | 152篇 |
原子能技术 | 8篇 |
自动化技术 | 148篇 |
出版年
2022年 | 17篇 |
2021年 | 18篇 |
2020年 | 18篇 |
2019年 | 11篇 |
2018年 | 12篇 |
2017年 | 11篇 |
2016年 | 25篇 |
2015年 | 19篇 |
2014年 | 32篇 |
2013年 | 49篇 |
2012年 | 56篇 |
2011年 | 64篇 |
2010年 | 49篇 |
2009年 | 46篇 |
2008年 | 50篇 |
2007年 | 49篇 |
2006年 | 34篇 |
2005年 | 31篇 |
2004年 | 33篇 |
2003年 | 24篇 |
2002年 | 33篇 |
2001年 | 14篇 |
2000年 | 24篇 |
1999年 | 24篇 |
1998年 | 27篇 |
1997年 | 26篇 |
1996年 | 14篇 |
1995年 | 15篇 |
1994年 | 15篇 |
1993年 | 12篇 |
1992年 | 13篇 |
1991年 | 15篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 15篇 |
1987年 | 20篇 |
1986年 | 7篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 12篇 |
1975年 | 10篇 |
1972年 | 8篇 |
1971年 | 6篇 |
1970年 | 7篇 |
排序方式: 共有1107条查询结果,搜索用时 15 毫秒
61.
Hubert Chanson 《Canadian Metallurgical Quarterly》2010,136(11):940-944
The present study examines the free-surface properties of undular tidal bores observed for 1相似文献
62.
Allaoua Achouri Joyce Irene Boye Denis Belanger Tiphaine Chiron Varoujan A. Yaylayan Faustinus K. Yeboah 《Food research international (Ottawa, Ont.)》2010,43(5):1494-1504
This study describes an extraction process for the preparation of highly purified calcium precipitated glycinin (11S). Initial extraction of soy proteins using isoelectric precipitation at pH 6.8 followed by cryo-precipitation yielded 4.2% product (11S) recovery with 98% protein purity for the control extracted with NaOH. Addition of calcium chloride (CaCl2) doubled the extraction yield (9%) compared to the control and when two other salts were used (i.e., sodium (Na2SO4) and ammonium (NH4)2SO4 sulfate, average yields of 4.4% and 5.17%, respectively). Thermal and molecular stability under varying conditions (pH, salts, SDS as a protein structure perturbing agent), and effect of glycation on functional and structural properties were investigated. Size exclusion chromatography and electrophoresis confirmed the predominance of a major band with MW of ~342 kDa with 98.4% purity. Differential scanning calorimetry (DSC) yielded one endothermic transition peak at 95.5 °C. Denaturation temperatures were >100 °C for all salt concentrations studied. The pH had a dominant influence on the structural properties of glycinin. In the presence of NaCl and CaCl2 (0.2–1 M), the protein structure showed very little denaturation and no aggregation bands were observed even on heating to 95 °C. Lower SDS concentrations (0.5–1%) resulted in denaturation and aggregation, while at 2% SDS only denaturation was observed. Glycation did not alter the conformational structure of protein. Improvements in surface properties were observed with moderate degree of glycation (6–24 h). 相似文献
63.
Tiago Bender Wermuth Mario Norberto Baibich Tania Maria Hubert Ribeiro Carlos Pérez Bergmann 《Ceramics International》2018,44(5):4758-4765
We studied the molar ratio effects of niobium and potassium precursors on the structure and morphology of potassium niobate powders prepared via microwave-assisted hydrothermal synthesis (MaHS). KNbO3 nanostructures in the form of nanotowers and nanocubes were obtained at reduced synthesis times (30–240 min). The products were characterized via XRD, Raman spectroscopy, SEM, and TEM; band gap calculations used diffuse reflectance data. The results indicate that KNbO3 nanostructures were obtained with crystallite sizes ranging from 33 to 52 nm. An orthorhombic crystalline structure was formed from the increase of KOH at a molar ratio Nb2O5:KOH (1:8 to 1:16 M). The band-gap of 3.1–3.3 eV has potential use in photodegradation applications. 相似文献
64.
Dr. Simon Schramm Luca Agnetta Dr. Marcel Bermudez Hubert Gerwe Matthias Irmen Dr. Janine Holze Dr. Timo Littmann Prof. Gerhard Wolber Dr. Christian Tränkle Prof. Michael Decker 《ChemMedChem》2019,14(14):1349-1358
Recently, investigations of the complex mechanisms of allostery have led to a deeper understanding of G protein-coupled receptor (GPCR) activation and signaling processes. In this context, muscarinic acetylcholine receptors (mAChRs) are highly relevant due to their exemplary role in the study of allosteric modulation. In this work, we compare and discuss two sets of putatively dualsteric ligands, which were designed to connect carbachol to different types of allosteric ligands. We chose derivatives of TBPB [1-(1′-(2-tolyl)-1,4′-bipiperidin-4-yl)-1H-benzo[d]imidazol-2(3H)-one] as M1-selective putative bitopic ligands, and derivatives of benzyl quinolone carboxylic acid (BQCA) as an M1 positive allosteric modulator, varying the distance between the allosteric and orthosteric building blocks. Luciferase protein complementation assays demonstrated that linker length must be carefully chosen to yield either agonist or antagonist behavior. These findings may help to design biased signaling and/or different extents of efficacy. 相似文献
65.
Reviews the books, Drogues et dépendances by Jef-Louis Bonnardeaux (1983) and Toxicomanies by Dollard Cormier (1983. The book by Bonnardeaux is clearly written and is accompanied by illustrations. However, one doubts the utility of the representation of many biochemical formulas. One wishes also for a better structuring of the various chapters. The book by Cormier is an excellent complement to the Bonnardeaux book. Drug addiction is presented as a life style expressing a solution to problems of existence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
66.
67.
The slags formed in the LD vessel during the refining process turn out with different chemical compositions, mineralogical structures and physical properties, in dependence on the charging and processing conditions. Electron probe microanalysis (EPMA) combined with a data processing method for mineralogical analysis was used to characterize the mineralogical phases in LD slags and moreover to determine their volume fractions. By this method some correlations between the phase contents and the chemical composition of LD slags were established. The diagrams gained from this work have proven to be a valuable aid for understanding the interrelationships between the chemical composition, the mineralogical structure and some physical properties of LD slags. 相似文献
68.
Intermittent Switching Between Potential Flow and Turbulence in Superfluid Helium at mK Temperatures
Michael Niemetz Hubert Kerscher Wilfried Schoepe 《Journal of Low Temperature Physics》2002,126(1-2):287-296
Superfluid flow around an oscillating microsphere is investigated at temperatures down to 25 mK. Stable laminar flow below a critical velocity and turbulence at large drives are found to be separated below 0.5 K by an intermediate range of driving forces where the flow is unstable, intermittently switching between laminar and turbulent phases. We have recorded time series of this switching phenomenon and have made a statistical analysis of the switching probability. The mean lifetime of the turbulent phases grows with increasing drive and becomes infinite at a critical value. Stability of the laminar phases above the critical velocity is limited by natural background radioactivity or cosmic rays. 相似文献
69.
Andrzej Huczko Hubert Lange Ewa Ca ko Hanna Grubek-Jaworska Pawe Droszcz 《Fullerenes, Nanotubes and Carbon Nanostructures》2001,9(2):251-254
To determine whether carbon nanotubes can induce any significant health hazards we applied methods routinely used in the pathophysiological testing of asbestos-induced disease to show that the soot with a high content of CNTs does not induce any abnormalities of pulmonary function or measurable inflammation in guinea pigs treated with carbon nanotubes. 相似文献
70.