全文获取类型
收费全文 | 593篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 11篇 |
综合类 | 1篇 |
化学工业 | 146篇 |
金属工艺 | 10篇 |
机械仪表 | 10篇 |
建筑科学 | 28篇 |
能源动力 | 29篇 |
轻工业 | 68篇 |
水利工程 | 5篇 |
石油天然气 | 3篇 |
无线电 | 50篇 |
一般工业技术 | 95篇 |
冶金工业 | 30篇 |
原子能技术 | 4篇 |
自动化技术 | 144篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 14篇 |
2021年 | 21篇 |
2020年 | 18篇 |
2019年 | 27篇 |
2018年 | 33篇 |
2017年 | 22篇 |
2016年 | 34篇 |
2015年 | 23篇 |
2014年 | 44篇 |
2013年 | 59篇 |
2012年 | 33篇 |
2011年 | 43篇 |
2010年 | 29篇 |
2009年 | 40篇 |
2008年 | 30篇 |
2007年 | 25篇 |
2006年 | 16篇 |
2005年 | 12篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 8篇 |
1996年 | 7篇 |
1995年 | 1篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 7篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 3篇 |
1970年 | 1篇 |
排序方式: 共有634条查询结果,搜索用时 15 毫秒
51.
Gerardo Aragon-Camarasa Haitham Fattah J. Paul Siebert 《Robotics and Autonomous Systems》2010,58(3):276-286
This paper presents the results of an investigation and pilot study into an active binocular vision system that combines binocular vergence, object recognition and attention control in a unified framework. The prototype developed is capable of identifying, targeting, verging on and recognising objects in a cluttered scene without the need for calibration or other knowledge of the camera geometry. This is achieved by implementing all image analysis in a symbolic space without creating explicit pixel-space maps. The system structure is based on the ‘searchlight metaphor’ of biological systems. We present results of an investigation that yield a maximum vergence error of ~6.5 pixels, while ~85% of known objects were recognised in five different cluttered scenes. Finally a ‘stepping-stone’ visual search strategy was demonstrated, taking a total of 40 saccades to find two known objects in the workspace, neither of which appeared simultaneously within the field of view resulting from any individual saccade. 相似文献
52.
Gerardo C Saucedo Pedro B Gonzlez Sergio M Revah Gustavo G Viniegra Maurice Raimbault 《Journal of the science of food and agriculture》1990,50(4):467-477
The major effect of Lactobacillus inoculation on laboratory cassava (Manihot esculenta Crantz) silage was a change from a heterofermentative pattern observed in natural silage to a homofermentation. Small amounts of starter culture (1% v/w) were required to produce a high level of lactic acid (> 28 g kg?1 DM) and to reach a pH of at least 4. The Gompertz model was used to evaluate the effect of inoculation level on the lactic formation based on kinetic criteria. Also an empirical pH lactic acid correlation was proposed to monitor the progress of ensiling, based solely on pH measurements. The simulation model may be used to improve guidelines for silo safety and to evaluate the effect of lactobacilli inoculants. 相似文献
53.
54.
Mu?oz Ricardo F.; McQuaid John R.; González Gerardo M.; Dimas Juanita; Rosales Verónica A. 《Canadian Metallurgical Quarterly》1999,67(4):502
Clinical depression is frequently unrecognized, even in health care settings. This study (a) reports high levels of major depressive episodes (MDEs) and depressive symptoms in a public sector women's clinic, (b) compares computerized voice recognition with live interviews, and (c) compares Spanish and English versions of the depression-screening instruments. Patients (N?=?104) completed face-to-face interviews and/or computerized voice recognition interviews in counterbalanced order; 38% scored positive for current MDE, and 67% scored positive for lifetime MDE. The mean score on the Center for Epidemiological Studies Depression scale (CES-D) was 22.1 (SD?=?12.1), with 68% scoring 16 or above. No differences were found on either measure between English and Spanish speakers. Overall agreement between computer and live interviews was as follows: κ?=?.82 for both current and lifetime MDE and r?=?.89 for CES-D scores. Kappas between the MDE Screener developed for this study and the Primary Care Evaluation of Mental Disorders were .75 for live interviews and .81 for the computerized version. Depression screening with computerized voice recognition methods yielded results comparable with those of live interviews in both English and Spanish. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
55.
Gerardo Iñiguez Rafael A. Barrio János Kertész Kimmo K. Kaski 《Computer Physics Communications》2011,182(9):1866-1869
In a previous paper we proposed a model to study the dynamics of opinion formation in human societies by a co-evolution process involving two distinct time scales of fast transaction and slower network evolution dynamics. In the transaction dynamics we take into account short range interactions as discussions between individuals and long range interactions to describe the attitude to the overall mood of society. The latter is handled by a uniformly distributed parameter α, assigned randomly to each individual, as quenched personal bias. The network evolution dynamics is realised by rewiring the societal network due to state variable changes as a result of transaction dynamics. The main consequence of this complex dynamics is that communities emerge in the social network for a range of values in the ratio between time scales. In this paper we focus our attention on the attitude parameter α and its influence on the conformation of opinion and the size of the resulting communities. We present numerical studies and extract interesting features of the model that can be interpreted in terms of social behaviour. 相似文献
56.
EJ Goldstein DM Citron M Hudspeth S Hunt Gerardo CV Merriam 《Canadian Metallurgical Quarterly》1997,41(7):1552-1557
The in vitro activity of Bay 12-8039, a new oral 8-methoxyquinolone, was compared to the activities of 11 other oral antimicrobial agents (ciprofloxacin, levofloxacin, ofloxacin, sparfloxacin, azithromycin, clarithromycin, amoxicillin clavulanate, penicillin, cefuroxime, cefpodoxime, and doxycycline) against 250 aerobic and 140 anaerobic bacteria recently isolated from animal and human bite wound infections. Bay 12-8039 was active against all aerobic isolates, both gram-positive and gram-negative isolates, at < or = 1.0 microg/ml (MICs at which 90% of isolates are inhibited [MIC90s < or = 0.25 microg/ml) and was active against most anaerobes at < or = 0.5 microg/ml; the exceptions were Fusobacterium nucleatum and other Fusobacterium species (MIC90s, > or = 4.0 microg/ml) and one strain of Prevotella loeschii (MICs, 2.0 microg/ml). In comparison, the other quinolones tested had similar in vitro activities against the aerobic strains but were less active against the anaerobes, including peptostreptococci, Porphyromonas species, and Prevotella species. The fusobacteria were relatively resistant to all the antimicrobial agents tested except penicillin G (one penicillinase-producing strain of F. nucleatum was found) and amoxicillin clavulanate. 相似文献
57.
Sebastian Ibarra-Rojas Author Vitae Gerardo Espinosa-Pérez Author Vitae 《Automatica》2004,40(6):1079-1085
The current problems to successfully apply sensorless controllers for induction motors are the existence of operation regimes for which the performance is remarkably deteriorated, due to the difficulties in estimating correctly motor speed and flux, and the lack of a theoretical explanation for this kind of behavior. In this paper a global observability analysis for these machines is carried out. It is first shown that all indistinguishable trajectories of the system, i.e. pairs of state trajectories with the same input/output behavior, can be described by a differential equation on a manifold, named here the indistinguishable dynamics. Studying the stability properties of this latter system it can be shown that the induction motor is not completely observable nor detectable in a local or in a global sense, and for every set of parameters. This implies that it is impossible to construct a state observer for the motor that converges for every trajectory of the system. Moreover, the indistinguishable dynamics provides a systematic method to study, understand and explain particular operation regimes, and this is illustrated by some case studies of practical relevant operating conditions. 相似文献
58.
Jos David Snchez-Martínez Ana Rita Garcia Gerardo Alvarez-Rivera Alberto Valds Maria Alexandra Brito Alejandro Cifuentes 《International journal of molecular sciences》2023,24(1)
Agrifood by-products and microalgae represent a low-cost and valuable source of bioactive compounds with neuroprotective properties. However, the neuroprotective effectiveness of therapeutic molecules can be limited by their capacity to cross the blood–brain barrier (BBB) and reach the brain. In this research, various green extracts from Robinia pseudoacacia (ASFE), Cyphomandra betacea (T33), Coffea arabica (PPC1), Olea europaea L., (OL-SS), Citrus sinensis (PLE100) by-products and from the microalgae Dunaliella salina (DS) that have demonstrated in vitro neuroprotective potential were submitted to an in vitro BBB permeability and transport assay based on an immortalized human brain microvascular endothelial cells (HBMEC) model. Toxicity and BBB integrity tests were performed, and the transport of target bioactive molecules across the BBB were evaluated after 2 and 4 h of incubation using gas and liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (GC/LC-Q-TOF-MS). The HBMEC-BBB transport assay revealed a high permeability of representative neuroprotective compounds, such as mono- and sesquiterpenoids, phytosterols and some phenolic compounds. The obtained results from the proposed in vitro BBB cellular model provide further evidence of the neuroprotective potential of the target natural extracts, which represent a promising source of functional ingredients to be transferred into food supplements, food additives, or nutraceuticals with scientifically supported neuroprotective claims. 相似文献
59.
Jardón-Pérez Luis E. Amaro-Villeda Adrian González-Rivera Carlos Trápaga Gerardo Conejo A. N. Ramírez-Argáez Marco A. 《Metallurgical and Materials Transactions B》2019,50(5):2121-2133
Metallurgical and Materials Transactions B - The planar laser-induced fluorescence (PLIF) technique was implemented to measure mixing time in a 1/17 water model of a 200-ton ladle furnace. The... 相似文献
60.
Gerardo Lara Jos Escobar Jos A De Los Reyes María C. Barrera Jos A. Colín Florentino R. Murrieta 《加拿大化工杂志》2005,83(4):685-694
USY faujasites (SiO2/Al2O3 = 12, 30 and 80) were used as hydrodesulphurization (HDS) catalyst supports. Mo, Co and P were impregnated at two concentrations: ~12.5, ~3 and ~1.6 mass %; ~18, ~5.5 and ~2.2 mass % (CL and HL series, respectively). Surface acidity decreased after Co‐Mo‐P deposition. Sulphided catalysts were tested in dibenzothiophene (DBT) HDS (320°C, 5.59 MPa). The HDS rate slightly increased with both SiO2 content and Co‐Mo‐P loading. High selectivity to hydrogenated products suggested deficient Mo promotion in CL solids. Improved Mo promotion by Co (HL series) could be responsible for higher activity and marked selectivity to desulphurization to biphenyl. 相似文献