全文获取类型
收费全文 | 929篇 |
免费 | 31篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 274篇 |
金属工艺 | 6篇 |
机械仪表 | 10篇 |
建筑科学 | 71篇 |
矿业工程 | 2篇 |
能源动力 | 20篇 |
轻工业 | 164篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 33篇 |
一般工业技术 | 86篇 |
冶金工业 | 206篇 |
原子能技术 | 1篇 |
自动化技术 | 81篇 |
出版年
2023年 | 11篇 |
2022年 | 19篇 |
2021年 | 28篇 |
2020年 | 13篇 |
2019年 | 18篇 |
2018年 | 25篇 |
2017年 | 21篇 |
2016年 | 24篇 |
2015年 | 20篇 |
2014年 | 25篇 |
2013年 | 54篇 |
2012年 | 45篇 |
2011年 | 41篇 |
2010年 | 43篇 |
2009年 | 36篇 |
2008年 | 43篇 |
2007年 | 44篇 |
2006年 | 43篇 |
2005年 | 33篇 |
2004年 | 37篇 |
2003年 | 20篇 |
2002年 | 21篇 |
2001年 | 14篇 |
2000年 | 14篇 |
1999年 | 14篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 17篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 11篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1979年 | 5篇 |
1977年 | 5篇 |
1974年 | 5篇 |
1966年 | 12篇 |
1965年 | 13篇 |
1964年 | 9篇 |
1963年 | 13篇 |
1962年 | 9篇 |
1961年 | 12篇 |
1960年 | 11篇 |
排序方式: 共有960条查询结果,搜索用时 0 毫秒
51.
Sophie Couture Thomas G. Brown Jacques Tremblay N.M.K. Ng Ying Kin Marie Claude Ouimet Louise Nadeau 《Accident; analysis and prevention》2010,42(1):307-312
A first driving while impaired by alcohol (DWI) conviction is a key opportunity to identify offenders who are at high risk for recidivism. Detection of alcohol use disorder (AUD) is a major target of current DWI assessments. However, offenders frequently underreport their alcohol consumption, and use of biomarkers has been proposed as a more objective indicator. Among the best established are aspartate aminotranferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), mean corpuscular red blood cell volume (MCV), carbohydrate-deficient transferrin (CDT), and thiamine. To our knowledge, no research has directly verified whether AUD biomarkers predict DWI recidivism status. Using a cross-sectional design, this study tested three hypotheses related to the utility of biomarkers in DWI assessment.
Hypotheses
(1) DWI recidivists possess biomarkers indicative of greater prevalence of AUD compared to first-time offenders; (2) multiple biomarkers better differentiate first-time offenders from recidivists compared to individual biomarkers; and (3) biomarkers add significantly to the prediction of recidivism over and above psychosocial questionnaires.Methods
First-time offenders (n = 49) and recidivists (n = 95) participated in the study. In addition to self-reported information on sociodemographic and driving characteristics, data from several AUD questionnaires were gathered: Michigan Alcoholism Screening Test, Alcohol Use Disorders Identification Test, Composite International Diagnostic Interview, and Timeline Follow-Back. Blood samples were collected to measure AST, ALT, GGT, MCV, CDT, and thiamine.Results
AUD biomarkers, taken individually or in combination, did not indicate that recidivists had more frequent AUD compared to first-time offenders. Also, they failed to significantly differentiate first-time offenders from recidivists or predict recidivism status. Finally, the superiority of biomarkers over psychosocial AUD questionnaires was not supported in the laboratory setting.Conclusion
The present findings suggest that biomarkers of chronic patterns of heavy drinking may not be adequate to capture the multiple processes that appear to promote recidivism (e.g., binge drinking, other risky behavioural and personality features). Despite their objectivity, caution is warranted in the interpretation of a positive score on these biomarkers in DWI assessment. Longitudinal research is needed to more comprehensively explore the relationship between positive biomarkers in first-time offenders and their risk of becoming recidivists. 相似文献52.
Maureen T. Ross Rena Cruz Trent L. Brooks-Richards Louise M. Hafner Sean K. Powell Maria A. Woodruff 《Virtual and Physical Prototyping》2018,13(4):255-265
Congenital facial anomalies, such as microtia (malformation of the external ear), lead to significant psychosocial effects starting from early childhood. Three-dimensional (3D) scanning and advanced manufacturing are being investigated as a cheaper and more personalised method of fabricating reconstructive treatments for patients compared to traditional approaches. To date, most case studies have used expensive 3D scanners, yet, there is potential for low-cost devices to provide comparable results. This study aimed to investigate these different approaches. Both ears of 16 adult participants were scanned with three devices: Artec Spider (Artec Group), Intel® RealSense? (Intel), and the Apple iPhone® 7 (Apple Inc.) combined with photogrammetry using 90, 60 and 30 photographs. The scanning time, processing time, accuracy, completeness, resolution and repeatability of each technique were assessed using the Artec Spider as a reference scanner. Our results show that the iPhone had the longest processing time however, this decreased nine-fold when reducing the number of photos from 90 to 30. There was no significant difference in the accuracy, completeness or repeatability of the iPhone scans with 90 photographs (1.4?±?0.6?mm, 79.9%, 1.0?±?0.1?mm), 60 photographs (1.2?±?0.2, 79.3%, 0.9?±?0.2?mm) or 30 photographs (1.2?±?0.3?mm, 74.3%, 1.0?±?0.2?mm). The Intel RealSesne performed significantly worse in each parameter (1.8?±?03?mm; 46.6%, 1.4?±?0.5). Additionally, the RealSense had significantly lower resolution with not enough detail captured for the application. These results demonstrate that the ear can be accurately 3D scanned using iPhone photographs. We would recommend capturing between 30 and 60 photographs of the ear to create a scan that is accurate but without the downfall of long processing time. Using these methods we aim to provide a more comfortable setting for the patient and a lower-cost and more personalised ear prosthesis. 相似文献
53.
In this paper, an original result in terms of a sufficient condition to test the identifiability of nonlinear delayed-differential models with constant delays and multi-inputs is given. The identifiability is studied for the linearized system and a criterion for linear systems with constant delays is provided, from which the identifiability of the original nonlinear system can be proved. This result is obtained by combining a classical identifiability result for nonlinear ordinary differential systems due to Grewal and Glover (1976) with the identifiability of linear delayed-differential models developed by Orlov, Belkoura, Richard, and Dambrine (2002). This paper is a generalization of Denis-Vidal, Jauberthie, and Joly-Blanchard (2006), which deals with the specific case of nonlinear delayed-differential models with two delays and a single input. 相似文献
54.
55.
Herman Louise M.; Abichandani Sheila L.; Elhajj Ali N.; Herman Elia Y. K.; Sanchez Juliana L.; Pack Adam A. 《Canadian Metallurgical Quarterly》1999,113(4):347
The authors tested a dolphin's (Tursiops truncatus) understanding of human manual pointing gestures to 3 distal objects located to the left of, to the right of, or behind the dolphin. The human referred to an object through a direct point (Pd), a cross-body point (Px), or a familiar symbolic gesture (S). In Experiment 1, the dolphin responded correctly to 80% of Pds toward laterally placed objects but to only 40% of Pds to the object behind. Responding to objects behind improved to 88% in Experiment 2 after exaggerated pointing was briefly instituted. Spontaneous comprehension of Pxs also was demonstrated. In Experiment 3, the human produced a sequence of 2 Pds, 2 Pxs, 2 Ss, or all 2-way combinations of these 3 to direct the dolphin to take the object referenced second to the object referenced first. Accuracy ranged from 68% to 77% correct (chance?=?17%). These results established that the dolphin understood the referential character of the human manual pointing gesture. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
Lynnette D. Madsen Louise Weaver Henrik Ljungcrantz Alison J. Clark 《Journal of Electronic Materials》1998,27(5):418-426
The microstructure of the Pt/Ti/SiO2/Si structure has been investigated by scanning and transmission electron microscopy. Pt films of 100 nm thickness deposited
by sputtering or evaporation onto unheated substrates gave complete coverage of the underlying Ti layer and showed a granular
and faceted structure with grains ∼20 nm in diameter. They did not exhibit hillocks or surface TiOx formation. X-ray diffraction was used to examine the film stress through use of the sin2ψ method with bulk values for the elastic constants (v=0.39, E=162 GPa). The as-deposited sputtered film had a compressive
stress of ∼540 MPa, while the evaporated films had tensile stresses of ∼630 MPa. The films then received a 400°C rapid thermal
anneal (RTA) for 90 s and a subsequent RTA of 650°C for 30s. Further investigation of the film stresses and microstructure
were made after each annealing step. After the low temperature anneal, the film stress for the sputtered film became tensile.
Plan-view sections examined by transmission electron microscopy (TEM) showed that the as-deposited sputtered films were dense
but became porous after annealing. Initially, the evaporated films had a less dense microstructure, but were more stable with
annealing. Little change in the stress for the evaporated film was observed after this initial low temperature annealing step.
Additional annealing of the evaporated and sputtered samples caused complete consumption of the Ti layer including some TiOx formation from the underlying SiO2 layer and marked interaction with the Pt; however, little change in the stress was found. The surface of the Pt film revealed
larger grains, but otherwise remained unaffected. The underlying phase changes were minimized once the Ti layer had reacted
with the Pt. Due to the ratio of the layers, Pt:Ti of 2:1, the surface of the Pt was unaffected. 相似文献
57.
Holden Ronald R.; Wasylkiw Louise; Starzyk Katherine B.; Book Angela S.; Edwards Melanie J. 《Canadian Metallurgical Quarterly》2006,38(1):24
Four studies investigated the dimensionality of the NEO Five-Factor Inventory (NEO-FFI; P. T. Costa & R. R. McCrae, 1992). In Study 1, four inferential dimensions and four clusters represented the NEO-FFI when 114 undergraduates freely sorted items into categories. Construct validity for four item-clusters derived from the inferential space was obtained in Study 2 based on self-report with 304 undergraduates. Study 3 validated these inferential clusters using self and peer reports for 420 undergraduates. Study 4 validated the cluster scales for predicting quality of life and significant social and cultural behaviours for 110 undergraduates. Implications for implicit personality theory, the number of dimensions issue in personality, and test construction are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
58.
Savage Robert S.; Abrami Philip; Hipps Geoffrey; Deault Louise 《Canadian Metallurgical Quarterly》2009,101(3):590
This study reports a randomized controlled trial evaluation of a computer-based balanced literacy intervention, ABRACADABRA (http://grover.concordia.ca/abra/version1/abracadabra.html). Children (N = 144) in Grade 1 were exposed either to computer activities for word analysis, text comprehension, and fluency, alongside shared stories (experimental groups), or to balanced literacy approaches delivered by their classroom teachers (control group). Two computer-based interventions—a phoneme-based synthetic phonics method and a rime-based analytic phonics method—were contrasted. Children were taught 4 times per week for 12 weeks in small groups. There were significant improvements in letter knowledge in the analytic phonics program and significant improvements in phonological awareness, listening comprehension, and reading comprehension at immediate posttest and in phonological awareness and reading fluency at a delayed posttest in the synthetic phonics program. Effect size analyses confirmed that both interventions had a significant impact on literacy at both posttests. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
59.
60.