全文获取类型
收费全文 | 653篇 |
免费 | 30篇 |
专业分类
化学工业 | 142篇 |
金属工艺 | 11篇 |
机械仪表 | 5篇 |
建筑科学 | 57篇 |
矿业工程 | 1篇 |
能源动力 | 9篇 |
轻工业 | 84篇 |
水利工程 | 7篇 |
无线电 | 81篇 |
一般工业技术 | 85篇 |
冶金工业 | 118篇 |
原子能技术 | 5篇 |
自动化技术 | 78篇 |
出版年
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 22篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 12篇 |
2017年 | 13篇 |
2016年 | 19篇 |
2015年 | 10篇 |
2014年 | 23篇 |
2013年 | 39篇 |
2012年 | 23篇 |
2011年 | 35篇 |
2010年 | 26篇 |
2009年 | 39篇 |
2008年 | 25篇 |
2007年 | 32篇 |
2006年 | 27篇 |
2005年 | 21篇 |
2004年 | 20篇 |
2003年 | 31篇 |
2002年 | 16篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 24篇 |
1998年 | 26篇 |
1997年 | 13篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1965年 | 2篇 |
1956年 | 1篇 |
1954年 | 2篇 |
排序方式: 共有683条查询结果,搜索用时 15 毫秒
1.
Nazir Kizzie‐Hayford Doris Jaros Yvonne Schneider Harald Rohm 《International Journal of Food Science & Technology》2015,50(2):381-388
A standard method for the extraction of tiger nut milk has been introduced. It has been shown that, although milling duration improves the yield of tiger nut milk solids and its nutrient composition, there is a quantifiable loss of nutrient in the pressing residue during milk extraction. Milling duration improved the colloidal stability of the milk against creaming during 16 h of storage. A higher milling intensity resulted in the aggregation of biological polymers which resulted in colloidal destabilisation. Milling improved the lightness and stability and reduced browning rate of the tiger nut milk during storage. This report is important for the production of tiger nut milk of consistent and comparable characteristics. Milling has been introduced as a processing method for the qualitative and quantitative modulation of the properties of tiger nut milk. It is recommended to develop further strategies to improve the colloidal stability of tiger nut milk as a beverage. 相似文献
2.
3.
4.
The dehydroalkylation of toluene with ethane to the isomeric ethyltoluenes was studied on 0.4Pt/H-ZSM-5 at varying contact
times (1/WHSV). At a high contact time of 1.0 h, toluene disproportionation and hydrogenolysis reactions dominate, resulting
in low selectivity to the desired ethyltoluenes via the alkylation reaction. However, at a low contact time of 0.12 h side
reactions are eliminated, resulting in maximum selectivities to the kinetically favored ethyltoluenes and hydrogen. Results
at high selectivities to ethyltoluenes provide significant insight into reaction pathways. 相似文献
5.
Delevoye-Turrell Yvonne; Giersch Anne; Wing Alan M.; Danion Jean-Marie 《Canadian Metallurgical Quarterly》2007,116(1):56
Many everyday activities depend on the capacity to organize and smoothly execute motor sequences. The authors tested the hypothesis that a sequencing deficit is associated with schizophrenia. They used a new method to distinguish between lower and higher order mechanisms for the impairment. The 1st task involved triggered sequences in which sensory information from 1 movement was the cue for initiation of the following movement. Results showed that the motor sequences were performed as fluently in patients as in controls. The 2nd and 3rd tasks involved sequences in which the entire movement sequence could be preplanned. Patients executed the sequences less fluently than controls but only under the condition where action sequences were required. Furthermore, the patients' fluency deficit increased with sequence complexity. The high discrimination power of Task 3 gave the authors a means to control for a potential psychometric confound involving differential discriminating power and to argue in favor of a specific higher order motor fluency deficit in patients with schizophrenia. It is suggested that basic lower order mechanisms that integrate sensory information with outgoing motor commands are preserved in schizophrenia, whereas higher order integrative mechanisms that are required for the smooth coordination of motor sequences are impaired. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
DR Gehlert DT Stephenson DA Schober K Rash JA Clemens 《Canadian Metallurgical Quarterly》1997,31(5):705-713
Peripheral benzodiazepine receptors (PBRs) are expressed in a variety of tissues but are normally found at low levels in the brain. Following various types of nerve injury, a reactive gliosis results that exhibits a high expression of this receptor. To further characterize the expression of PBRs following neuronal injury, we evaluated PBR expression in the facial nucleus following facial nerve axotomy (FNA). Injury to a peripheral nerve results in a complex series of metabolic and morphological changes around the injured neuron. Transections of the facial nerve results in a rapid activation of both astrocytes and microglia around axotomized motor neurons. FNA resulted in an increase in the staining for both astrocytes (glial fibrillary acidic protein) and activated microglia (OX42). There was also a reduction in synaptic contacts with the motor nucleus as evidenced by reduced staining for the synaptic marker, synaptophysin. In sections labeled with [3H]-PK11195, the subsequent autoradiograms displayed marked increases in the labeling for PBRs. This increase was observed at 5, 7 and 10 days after nerve transection. The increase was primarily in the level of expression (Bmax), with no change in the affinity of the ligand (Kd). The increase in PBR expression after FNA supports the hypothesis that PBRs can be used as a sensitive marker for CNS injury. 相似文献
7.
Hispanic children are the fastest growing segment of the population. Numerous factors place them at-risk for school success. This study examined the effects of Child-Centered Play Therapy (CCPT) compared to a curriculum-based small group intervention with 29 Hispanic children referred for school counseling due to behavior problems. Children were assigned to treatment groups by random drawing within grade levels. Treatment was provided by Hispanic bilingual counselors. Statistical analysis revealed that, according to parent report, children receiving CCPT showed statistically significant decreases in externalizing behavior problems, compared to the curriculum-based treatment group. Effect size calculations revealed that CCPT demonstrated a large treatment effect on externalizing behavior problems and a moderate treatment effect on internalizing behavior problems. Cultural considerations and recommendations for practice and future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Yvonne Conrad 《Datenschutz und Datensicherheit - DuD》2006,30(7):405-409
Zusammenfassung Der Wandel der Gesellschaft im Umgang mit personenbezogenen Daten sowie die stete Entwicklung technischer M?glichkeiten in
der Datenverarbeitung haben l?ngst dazu beigetragen, dass Verbraucherinnen und Verbraucher im Wege der Erstellung umfassender
Konsumentenprofile immer st?rker in die Rolle gl?serner Kunden gedr?ngt werden. Daten sammelnde Unternehmen stellen insoweit
eine Gefahr für das Recht der Einzelnen auf informationelle Selbstbestimmung dar. Vor diesem Hintergrund befasst sich der
Beitrag mit den datenschutzrechtlichen Anforderungen an Kundenbindungsprogramme und zeigt, wie sie datenschutzgerecht und
verbraucherfreundlich gestaltet werden k?nnen. 相似文献
9.
HH Henneicke-von Zepelin U Mrowietz L F?rber K Bruck-Borchers C Schober J Huber G Lutz R Kohnen E Christophers D Welzel 《Canadian Metallurgical Quarterly》1993,129(6):713-717
We report the results of a multicentre, double-blind, placebo-controlled study of topical therapy with omega-3-polyunsaturated fatty acids (omega-3-PUFA) in 52 patients suffering from moderate plaque-type psoriasis. In each patient, two similar stable psoriatic plaques served as indicator lesions for the study. One indicator lesion was randomly assigned to treatment with topical preparations of highly purified omega-3-PUFA in one of two concentrations (1 or 10%), and the other was treated with placebo. Efficacy assessment was based on changes in local psoriasis severity index, area involved, erythema, desquamation, induration and pruritus. After 8 weeks of treatment, all indicator lesions had improved significantly, compared with baseline. However, no statistically or clinically relevant differences between the omega-3-PUFA-treated and the placebo-treated lesions were found. Therapy was well tolerated and, apart from one patient who developed perilesional eczema, no clinically relevant adverse events occurred. In conclusion, topical omega-3-PUFA were not effective in a randomized, placebo-controlled, double-blind setting. Results of non-blind trials should be (re-)considered with caution. 相似文献
10.
Lampe L.H.-J. Schober R. Fischer R.F.H. 《Wireless Communications, IEEE Transactions on》2003,2(3):582-590
In this paper, powerful coding techniques for differential space-time modulation (DSTM) over Rayleigh flat fading channels and noncoherent detection without channel state information at the receiver are investigated. In particular, multilevel coding, bit-interleaved coded modulation, and so-called hybrid coded modulation (HCM) are devised and compared. For improved noncoherent reception multiple-symbol differential detection (MSDD) is adapted to DSTM. In order to reduce the computational effort required for MSDD, a low-complexity version of MSDD is applied. Evaluating the ergodic channel capacity for the different schemes as appropriate performance measure, HCM with simplified MSDD is shown to offer a favorable tradeoff between complexity and achievable power efficiency. Simulation results employing turbo codes in properly designed HCM schemes confirm the predictions from information theory. 相似文献