全文获取类型
收费全文 | 238篇 |
免费 | 8篇 |
专业分类
电工技术 | 1篇 |
综合类 | 1篇 |
化学工业 | 86篇 |
金属工艺 | 2篇 |
机械仪表 | 2篇 |
建筑科学 | 2篇 |
能源动力 | 4篇 |
轻工业 | 41篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 7篇 |
一般工业技术 | 38篇 |
冶金工业 | 30篇 |
原子能技术 | 1篇 |
自动化技术 | 29篇 |
出版年
2023年 | 6篇 |
2022年 | 14篇 |
2021年 | 14篇 |
2020年 | 3篇 |
2019年 | 9篇 |
2018年 | 4篇 |
2017年 | 8篇 |
2016年 | 7篇 |
2014年 | 4篇 |
2013年 | 14篇 |
2012年 | 16篇 |
2011年 | 17篇 |
2010年 | 11篇 |
2009年 | 12篇 |
2008年 | 11篇 |
2007年 | 17篇 |
2006年 | 10篇 |
2005年 | 8篇 |
2004年 | 11篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 2篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有246条查询结果,搜索用时 0 毫秒
21.
Perkins Kenneth A.; Marcus Marsha D.; Levine Michele D.; D'Amico Delia; Miller Amy; Broge Michelle; Ashcom Jacquelyn; Shiffman Saul 《Canadian Metallurgical Quarterly》2001,69(4):604
Women smokers concerned about weight gain (N?=?219) were randomly assigned to 1 of 3 adjunct treatments accompanying group smoking cessation counseling: (a) behavioral weight control to prevent weight gain (weight control); (b) cognitive–behavioral therapy (CBT) to directly reduce weight concern, in which dieting was discouraged; and (c) standard counseling alone (standard), in which weight gain was not explicitly addressed. Ten sessions were conducted over 7 weeks, and no medication was provided. Continuous abstinence was significantly higher at posttreatment and at 6 and 12 months of follow-up for CBT (56%, 28%, and 21%, respectively), but not for weight control (44%, 18%, and 13%, respectively), relative to standard (31%, 12%, and 9%, respectively). However, weight control, and to a lesser extent CBT, was associated with attenuation of negative mood after quitting. Prequit body mass index, but not change in weight or in weight concerns postquit, predicted cessation outcome at 1 year. In sum, CBT to reduce weight concerns, but not behavioral weight control counseling to prevent weight gain, improves smoking cessation outcome in weight-concerned women. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
22.
The influence of [Fe]-hydrogenase from Clostridium acetobutylicum was studied on the anaerobic corrosion of mild steel. Two short-circuited mild steel electrodes were exposed to the same solution and hydrogenase was retained on the surface of only one electrode thanks to a dialysis membrane. The galvanic current and the electrode potential were measured as a function of time in order to monitor the difference in electrochemical behaviour induced by the presence of hydrogenase. A sharp potential decrease of around 500 mV was controlled by the deoxygenating phase. When hydrogenase was introduced after complete deoxygenation, significant heterogeneous corrosion was observed under the vivianite deposit on the electrode in contact with hydrogenase, while the other electrode only showed the vivianite deposit, which was analysed by MEB and EDX. The effect of hydrogenase was then confirmed by monitoring the free potential of single coupons exposed or not to the enzyme in a classical cell after complete deoxygenating. In both phosphate and Tris-HCl buffers, the presence of hydrogenase increased the free potential around 60 mV and induced marked general corrosion. It was concluded that [Fe]-hydrogenase acts in the absence of any final electron acceptor by catalysing direct proton reduction on the mild steel surface. 相似文献
23.
The initial microstructures of two wheat flours (hard wheat flour and soft wheat flour) and flour components (starch, gluten, soluble pentosans and insoluble pentosans) were observed by scanning electron microscopy (SEM) and the changes in microstructure during hydration were described using environmental SEM (ESEM). SEM images permitted observation of the classical microstructure of wheat flour particles and starch granules. The initial microstructure of the purified fractions of flour components (gluten, soluble pentosans and insoluble pentosans) seemed largely dependent on the purification techniques, and could not thus directly be used to describe their in situ behavior during flour processing. ESEM observations of wheat flours and flour components during hydration first demonstrated slight changes in surface of particles that we associated to apparent swelling effects. The formation of a continuous aqueous phase between particles was observed for long hydration times. 相似文献
24.
Tomaselli S Esposito V Vangone P van Nuland NA Bonvin AM Guerrini R Tancredi T Temussi PA Picone D 《Chembiochem : a European journal of chemical biology》2006,7(2):257-267
Current views of the role of beta-amyloid (Abeta) peptide fibrils range from regarding them as the cause of Alzheimer's pathology to having a protective function. In the last few years, it has also been suggested that soluble oligomers might be the most important toxic species. In all cases, the study of the conformational properties of Abeta peptides in soluble form constitutes a basic approach to the design of molecules with "antiamyloid" activity. We have experimentally investigated the conformational path that can lead the Abeta-(1-42) peptide from the native state, which is represented by an alpha helix embedded in the membrane, to the final state in the amyloid fibrils, which is characterized by beta-sheet structures. The conformational steps were monitored by using CD and NMR spectroscopy in media of varying polarities. This was achieved by changing the composition of water and hexafluoroisopropanol (HFIP). In the presence of HFIP, beta conformations can be observed in solutions that have very high water content (up to 99 % water; v/v). These can be turned back to alpha helices simply by adding the appropriate amount of HFIP. The transition of Abeta-(1-42) from alpha to beta conformations occurs when the amount of water is higher than 80 % (v/v). The NMR structure solved in HFIP/H2O with high water content showed that, on going from very apolar to polar environments, the long N-terminal helix is essentially retained, whereas the shorter C-terminal helix is lost. The complete conformational path was investigated in detail with the aid of molecular-dynamics simulations in explicit solvent, which led to the localization of residues that might seed beta conformations. The structures obtained might help to find regions that are more affected by environmental conditions in vivo. This could in turn aid the design of molecules able to inhibit fibril deposition or revert oligomerization processes. 相似文献
25.
Inspired by the Multiplicative Exponential fragment of Linear Logic, we define a framework called the prismoid of resources where each vertex is a language which refines the λ-calculus by using a different choice to make explicit or implicit (meta-level) the definition of the contraction, weakening, and substitution operations. For all the calculi in the prismoid we show simulation of β-reduction, confluence, preservation of β-strong normalisation and strong normalisation for typed terms. Full composition also holds for all the calculi of the prismoid handling explicit substitutions. The whole development of the prismoid is done by making the set of resources a parameter of the formalism, so that all the properties for each vertex are obtained as a particular case of the general abstract proofs. 相似文献
26.
N‐Benzyl‐4‐((heteroaryl)methyl)benzamides: A New Class of Direct NADH‐Dependent 2‐trans Enoyl–Acyl Carrier Protein Reductase (InhA) Inhibitors with Antitubercular Activity 下载免费PDF全文
Ana Guardia Dr. Gulcin Gulten Dr. Raquel Fernandez Jesus Gómez Dr. Feng Wang Dr. Maire Convery Delia Blanco María Martínez Dr. Esther Pérez‐Herrán Marta Alonso Dr. Fátima Ortega Dr. Joaquín Rullás Dr. David Calvo Lydia Mata Dr. Robert Young Prof. James C. Sacchettini Dr. Alfonso Mendoza‐Losana Dr. Modesto Remuiñán Dr. Lluís Ballell Pages Dr. Julia Castro‐Pichel 《ChemMedChem》2016,11(7):687-701
Isoniazid (INH) remains one of the cornerstones of antitubercular chemotherapy for drug‐sensitive strains of M. tuberculosis bacteria. However, the increasing prevalence of multidrug‐resistant (MDR) and extensively drug‐resistant (XDR) strains containing mutations in the KatG enzyme, which is responsible for the activation of INH into its antitubercular form, have rendered this drug of little or no use in many cases of drug‐resistant tuberculosis. Presented herein is a novel family of antitubercular direct NADH‐dependent 2‐trans enoyl–acyl carrier protein reductase (InhA) inhibitors based on an N‐benzyl‐4‐((heteroaryl)methyl)benzamide template; unlike INH, these do not require prior activation by KatG. Given their direct InhA target engagement, these compounds should be able to circumvent KatG‐related resistance in the clinic. The lead molecules were shown to be potent inhibitors of InhA and showed activity against M. tuberculosis bacteria. This new family of inhibitors was found to be chemically tractable, as exemplified by the facile synthesis of analogues and the establishment of structure–activity relationships. Furthermore, a co‐crystal structure of the initial hit with the enzyme is disclosed, providing valuable information toward the design of new InhA inhibitors for the treatment of MDR/XDR tuberculosis. 相似文献
27.
Josa. Trujillo-Quijano Delia B. Rodriguez-Amaya W. Esteves Gerhard F. Plonis 《European Journal of Lipid Science and Technology》1990,92(6):222-226
In oils extracted from fresh and sterilized palm fruits (Elaeis guineensis, Jacq. tenera, dura dumpy and psifera and E. oleifera), cis-phytofluene, 13-cis-α-carotene, α-carotene, 13-cis-β-carotene, β-carotene, 9-cis-β-carotene, σ-carotene, zeaxanthin, --cryptoxanthin, poly-cis-lycopene, mono-lycopene and lycopene, were identified and quantified by normal phase open column chromatography (stepwise-elution), TLC, UV/Vis spectroscopy and specific chemical reactions. The sum of α- and β-carotene in all samples analysed was higher than 80% of the total carotenoid content, while the α/β-carotene ratios were W.9, 1/11.1, 1/22 and V2.6 for oils extracted from fresh fruits of dura dumpy, psifera, tenera and E. oleifera, respectively. Total carotenoid contents (pg/g) and vitamin A values (R. E./100 g) of these samples were 1 120.7 and 12 404 for dura dumpy, 283.2 and 3612 for psifera, 660.5 and 7630 for tenera and 1576.8 and 21691 for E. oleifera. The sterilization of fruits (127°C × 35 min.) resulted in isomerization of pigments and reduction of vitamin A values of approximately 45% and 25%, respectively. 相似文献
28.
Maria C. F. Ferreira Delia Kesner Laurence Puel 《Applicable Algebra in Engineering, Communication and Computing》1999,9(4):333-371
This paper studies preservation of β-strong normalization by two different confluent λ-calculi with explicit substitutions
defined in [96]; the particularity of these calculi, called λ
d
and λ
dn
respectively, is that both have a (weak) composition operator for substitutions. We apply an abstract simulation technique
to reduce preservation of β-strong normalization of λ
d
and λ
dn
to that of another calculus, called λ
f
having no composition operator. Then, preservation of β-strong normalization of λ
f
is shown using the same technique as in [2]. As a consequence, λ
d
and λ
dn
become the first λ-calculi with explicit substitutions having (weak) composition and preserving β-strong normalization. As
an aside, we also show how to apply our technique to reduce preservation of β-strong normalization of the calculus λ
v
in [20] to that of λ
f
.
Received: August 19, 1997; revised version: November 13, 1998 相似文献
29.
Waschbusch Daniel A.; Porter Stephen; Carrey Normand; Kazmi S. Omar; Roach Kerry A.; D'Amico Delia A. 《Canadian Metallurgical Quarterly》2004,36(2):97
We evaluated parent and teacher ratings of a large sample (N=1579) of elementary-school children in Canada to determine how different conceptualizations of disruptive behaviour are co-related and related to other measures of functioning. Parent and teacher ratings were consistent, and suggested three separate but correlated aspects of disruptive behaviour in children: (1) reactive/oppositional behaviour, (2) proactive/callous behaviour; and (3) inattention-impulsive-overactive behaviour. These were uniquely and significantly related to DSM-IV diagnostic scores and to other measure of impairment, indicating that they measure distinct aspects of disruptive behaviour in children. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
30.
We introduce a new higher-order rewriting formalism, called expression reduction systems with patterns (ERSP), where abstraction is allowed not only on variables but also on nested patterns with metavariables. These patterns are built
by combining standard algebraic patterns with choice constructors denoting cases. In other words, the nondeterministic choice between different rewrite rules which is inherent
to classical rewriting formalisms can be lifted here to the level of patterns. We show that confluence holds for a reasonable
class of systems and terms. 相似文献