全文获取类型
收费全文 | 4816篇 |
免费 | 184篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 39篇 |
综合类 | 5篇 |
化学工业 | 1149篇 |
金属工艺 | 82篇 |
机械仪表 | 79篇 |
建筑科学 | 215篇 |
矿业工程 | 20篇 |
能源动力 | 166篇 |
轻工业 | 366篇 |
水利工程 | 35篇 |
石油天然气 | 36篇 |
武器工业 | 2篇 |
无线电 | 430篇 |
一般工业技术 | 804篇 |
冶金工业 | 867篇 |
原子能技术 | 14篇 |
自动化技术 | 696篇 |
出版年
2023年 | 32篇 |
2022年 | 72篇 |
2021年 | 91篇 |
2020年 | 59篇 |
2019年 | 72篇 |
2018年 | 88篇 |
2017年 | 91篇 |
2016年 | 89篇 |
2015年 | 88篇 |
2014年 | 129篇 |
2013年 | 363篇 |
2012年 | 221篇 |
2011年 | 298篇 |
2010年 | 190篇 |
2009年 | 221篇 |
2008年 | 220篇 |
2007年 | 237篇 |
2006年 | 197篇 |
2005年 | 156篇 |
2004年 | 123篇 |
2003年 | 119篇 |
2002年 | 127篇 |
2001年 | 97篇 |
2000年 | 79篇 |
1999年 | 81篇 |
1998年 | 109篇 |
1997年 | 101篇 |
1996年 | 78篇 |
1995年 | 95篇 |
1994年 | 61篇 |
1993年 | 58篇 |
1992年 | 47篇 |
1991年 | 50篇 |
1990年 | 64篇 |
1989年 | 46篇 |
1988年 | 45篇 |
1987年 | 38篇 |
1986年 | 39篇 |
1985年 | 57篇 |
1984年 | 58篇 |
1983年 | 44篇 |
1982年 | 42篇 |
1981年 | 36篇 |
1980年 | 42篇 |
1979年 | 46篇 |
1978年 | 49篇 |
1977年 | 40篇 |
1976年 | 40篇 |
1975年 | 36篇 |
1973年 | 35篇 |
排序方式: 共有5005条查询结果,搜索用时 31 毫秒
21.
Merging uncertain information with semantic heterogeneity in XML 总被引:1,自引:1,他引:0
Semistructured information can be merged in a logic-based framework [6, 7]. This framework has been extended to deal with
uncertainty, in the form of probability values, degrees of beliefs, or necessity measures, associated with leaves (i.e. textentries)
in the XML documents [3]. In this paper we further extend this approach to modelling and merging uncertain information that
is defined at different levels of granularity of XML textentries, and to modelling and reasoning with XML documents that contain
semantically heterogeneous uncertain information on more complex elements in XML subtrees. We present the formal definitions
for modelling, propagating and merging semantically heterogeneous uncertain information and explain how they can be handled
using logic-based fusion techniques.
Anthony Hunter received a B.Sc. (1984) from the University of Bristol and an M.Sc. (1987) and Ph.D. (1992) from Imperial College, London.
He is currently a reader in the Department of Computer Science at University College London. His main research interests are:
Knowledge representation and reasoning, Analysing inconsistency, Argumentation, Default reasoning and Knowledge Fusion.
Weiru Liu is a senior lecturer at the School of Computer Science, Queen's University Belfast. She received her B.Sc. and M.Sc. degrees
in Computer Science from Jilin University, P.R China, and her Ph.D. degree in Artificial Intelligence from the University
of Edinburgh. Her main research interests include reasoning under uncertainty, knowledge representation and reasoning, uncertain
knowledge and information fusion, and knowledge discovery in databases. She has published over 50 journal and conference papers
in these areas. 相似文献
22.
Perkins Kenneth A.; Ciccocioppo Melinda; Jacobs Lynette; Doyle Todd; Caggiula Anthony 《Canadian Metallurgical Quarterly》2003,11(4):269
Nonpharmacological cues associated with drug intake may influence subjective and reinforcing effects of those drugs. Social drinkers (N = 80) participated in 2 sessions in which they rated and then consumed ad lib their preferred beer (with participants blind to brand). Visual and olfactory stimuli were obscured during 1 session (blocked) and not obscured during the other (unblocked). Dependent measures included ratings of "liking", "want another", and "desire to drink"; subjective mood; and ad lib beer consumption (reinforcement). Most ratings and ad lib consumption were lower during the blocked versus the unblocked condition. There were no interactions of blockade condition with sex and no effect of blockade on mood. These findings show that nonpharmacological stimuli associated with alcohol consumption influence alcohol's subjective and reinforcing effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
23.
OBJECTIVE: To determine the effect of area postrema AP on DOCA-salt induced hypertension in rat, with emphasis on renal hemodynamics. METHOD: Blood pressure, salt and water balances and renal hemodynamics were observed in AP ablated and sham-operated rats treated with DOCA-salt. RESULTS: In AP intact (API) rats, after one week of DOCA-salt treatment BP began elevating to statistical significance at the end of the second week (MAP 15.9 +/- 0.7 vs. 13.5 +/- 0.5 kPa), followed by a plateau period from the third to fifth week. In AP ablated (APX) rats, BP raised during the first week of DOCA-salt treatment. However, the elevation gradually disappeared and BP returned to baseline at the fifth week. Sodium balance study showed that DOCA-salt treatment induced significant sodium retention in API rat, while the sodium metabolism remained stable in APX group except in the first week. Basal renal hemodynamic parameters (GFR, RPF, UNaV, UV) were not changed at neither the beginning nor the end of the study. However, a small dose of hypertonic saline (7% NaCl 0.3 ml) injection caused a brisk rising of these four parameters in APX but not API group. CONCLUSION: AP plays an important role in normal salt and water metabolism and might be involved in pathogenesis of DOCA-salt hypertension through regulation for renal hemodynamics and body fluid homeostasis. 相似文献
24.
The interfacial stress intensity factors for three types of sandwich specimens: the single edge crack tensile specimen, the three point bend specimen and the four point shear specimen were obtained by the finite element analysis and compared with the asymptotic solutions. The results show that the geometric effect for mode II specimen is larger than mode I specimen. The limit curves for geometry factor equal to 1.05 were obtained to indicate the usable range of validity of the asymptotic solution. 相似文献
25.
26.
Anthony R. Tricker M. John Perkins Robert C. Massey David J. McWeeny 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1985,180(5):379-383
Zusammenfassung Der Gehalt an Nitrosoaminosäuren und ihr Anteil an den Gesamt-N-Nitrosoverbindungen im Fettgewebe von rohem Schinkenspeck wurde untersucht. In 80% der Proben wurde ein Gehalt an Nitrosoaminosäuren von bis zu 0,2 mg/kg festgestellt. Scheinbare Gesamt-N-Nitrosoverbindungen waren in allen Proben in einer Konzentration von 0,4 bis 3,7 mg (N-NO)/kg vorhanden. Die eigentlichen Nitrosoaminosäuren machen nur etwa 1% der scheinbaren Gesamt-N-Nitrosoverbindungen aus. Die Mehrzahl der scheinbaren Gesamt-N-Nitrosoverbindungen im Fettgewebe findet sich im nichtlöslichen Bindegewebe, wobei der verbleibende Rest chloroformlöslich ist.Summary The levels of nitrosoamino acids and apparent total N-nitroso compounds in the adipose tissue of raw bacon have been examined. Nitrosoamino acids were detected in 80% of the samples in levels of up to 0.2 mg/kg. Apparent total N-nitroso compounds were present in all samples in concentrations of between 0.4 and 3.7 mg (N-NO)/kg. Nitrosoamino acids accounted for approximately only 1 % of the apparent total N-nitroso compounds. The majority of the apparent total N-nitroso compounds in the adipose tissue were associated with the insoluble connective tissue fraction, with the remainder present as chloroform soluble species.
Einige Nitrosoaminosäuren im fettgewebe von Schinkenspeck und ihr anteil an der Konzentration der Gesamt-N-Nitrosoverbindungen相似文献
27.
I review arguments regarding hypnosis in forensic investigations, offer procedures of a nonhypnotic nature to enhance memory recall, and suggest guidelines for hypnosis in criminal cases. The effects of hypnosis on memory, as well as the concomitant dangers regarding those effects, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
Anthony L. Whitear 《Journal of the Institute of Brewing》1991,97(1):47-51
Laurence Bishop's contribution to the brewing industry over more than 50 years of research endeavour and committee activities is reviewed. Three research areas — prediction of extract, the effect of turbidity on yeast activity during fermentation and the development of a 3-vessel fermentation system — are used to highlight his achievements. Five topics with which the author was intimately involved, three of which were connected with Laurence Bishop's own researches, are used to describe the author's activities. These concerned the assessment of beer foam, the prediction of beer stability, the assessment of the bittering value of hops, time course changes in the analytical characteristic of an ale fermentation and the use of fractional factorial designs to facilitate experimental programmes. 相似文献
29.
30.
Harper David N.; McLean Anthony P.; Dalrymple-Alford John C. 《Canadian Metallurgical Quarterly》1994,108(4):691
Examined the effects of medial septal (MS) and mammillary body (MB) radio-frequency lesions in an automated delayed-matching-to-sample (DMTS) procedure using lever-position stimuli and rats. Memory performance pre- and postsurgery was assessed with a negative exponential decay function fitted to bias-free measures of recognition. Part 1 showed that MS, but not MB or sham-control surgery, impaired DMTS performance. This impairment in the MS group was best characterized as an increase in the rate of forgetting. Part 2 examined the interaction between MS and MB lesion effects and proactive interference arising from responses made on the previous DMTS trial. The results indicated that proactive interference effects were similar for all groups. These results provide further support for the critical role of the MS region in memory function but indicate that damage to this brain region does not disrupt memory function through a heightened sensitivity to proactive interference. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献