全文获取类型
收费全文 | 203篇 |
免费 | 11篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 44篇 |
金属工艺 | 2篇 |
机械仪表 | 2篇 |
建筑科学 | 6篇 |
能源动力 | 5篇 |
轻工业 | 53篇 |
水利工程 | 1篇 |
无线电 | 7篇 |
一般工业技术 | 17篇 |
冶金工业 | 50篇 |
原子能技术 | 1篇 |
自动化技术 | 25篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 12篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 8篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 8篇 |
2012年 | 12篇 |
2011年 | 16篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 9篇 |
2007年 | 6篇 |
2006年 | 10篇 |
2005年 | 8篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 6篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 5篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1969年 | 2篇 |
1962年 | 1篇 |
排序方式: 共有214条查询结果,搜索用时 15 毫秒
141.
Villarreal Julissa S.; Dykes James R.; Barea-Rodriguez Edwin J. 《Canadian Metallurgical Quarterly》2004,118(6):1166
A functional hippocampus is required for trace fear conditioning, which involves learning the association of a tone and shock that are separated over time. Young and aged rats received 10 trace conditioning trials. Twenty-four hours later, rats were tested for fear to the tone in a novel chamber by measuring freezing. The results showed significantly lower levels of freezing in aged rats as compared with young rats, which provides evidence of age-related memory impairments. Pseudorandom conditioning groups showed low levels of freezing, indicative of no associative memory. Age-related memory deficits were not found with delay conditioning, which suggests no age-related sensory-motor deficits. These data suggest that aging hinders the ability of the hippocampus to process information separated over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
142.
Abstract: Most research on Latino voting behavior conclusively finds that as a group, Latinos vote at lower rates than other racial and ethnic groups in the United States. In this article, we argue that given the appropriate circumstances, Latinos should be expected to vote at higher rates than other racial and ethnic groups. In particular, we think the presence of a viable Latino candidate will spur increased Latino turnout and that when Latinos candidates run for office, Latino voters will prefer the co‐ethnic candidate. Analyzing precinct level returns from the Los Angeles 2001 mayoral and the 2000 presidential elections we show this may be the case. High‐density Latino precincts show higher rates of turnout when Latino candidates are on the ballot, and these same precincts show heightened support for the co‐ethnic candidate. In fact, for the first time ever in Los Angeles, the 2001 mayoral election witnessed Latinos voting at the highest rates of any racial or ethnic group in the city. 相似文献
143.
The computation language of a DNA-based system consists of all the words (DNA strands) that can appear in any computation step of the system. In this work we define properties of languages which ensure that the words of such languages will not form undesirable bonds when used in DNA computations. We give several characterizations of the desired properties and provide methods for obtaining languages with such properties. The decidability of these properties is addressed as well. As an application we consider splicing systems whose computation language is free of certain undesirable bonds and is generated by nearly optimal comma-free codes. 相似文献
144.
Transforming growth factor-beta 1 (TGF-beta 1) is known to regulate cardiac cell function and its overexpression in the heart is thought to contribute to the development of cardiac hypertrophy and fibrosis. We wished to develop a high efficiency gene transfer method that could be used both in vitro and in vivo and result in the overexpression of TGF-beta 1. For this purpose, we constructed a replication-deficient human adenovirus 5 vector encoding for human TGF-beta 1 and used for control purposes an adenovirus lacZ vector. The adenovirus 5 construct was capable of infecting neonatal rat cardiac myocytes, fibroblasts and VSMCs. Of the three cell types, cardiac myocytes appear more susceptible to infection by the adenovirus 5 construct as assessed through beta-galactosidase staining. Infection of cardiac fibroblasts, myocytes and VSMCs with the hTGF-beta 1 adenovirus leads to the expression of hTGF-beta 1 mRNA and enhanced levels of bioactive and total TGF-beta 1 protein. Infection with hTGF-beta 1 adenovirus also results in enhanced levels of collagen type III gene expression in VSMCs and fibroblasts whereas in cardiac myocytes it leads to increased levels for sarcomeric and beta-actin. Thus, this adenoviral vector might be used for the exploration of in vivo effects of altered levels of cardiac TGF-beta 1. 相似文献
145.
DH Villarreal VN Ortiz JR Iturregui G Suarez N Duran 《Canadian Metallurgical Quarterly》1998,90(4-6):93-94
This is a case report of a newborn patient with imperforate anus, urethro-colonic fistula, perianal hamartoma, and bifid scrotum. Successful staged repair of these anomalies is described together with review of the embriology related to the case. 相似文献
146.
JP Heggers C Villarreal P Edgar S Wolf GL Klein SD John M Desai DN Herndon 《Canadian Metallurgical Quarterly》1998,133(11):1247-1250
BACKGROUND: Food and Drug Administration regulations state that ciprofloxacin hydrochloride may cause arthropathies. For this reason, such therapy is contraindicated in the pediatric population. However, several studies in children with cystic fibrosis have found the drug to be efficacious. Our hypothesis was that ciprofloxacin treatment is justified in the case of multiresistant organisms in burn populations. DESIGN: During a 4-year period (January 1, 1993, to December 31, 1997) we treated 56 of our pediatric burn patients with ciprofloxacin when cultures proved resistant to other antibiotics. The burn area was 65% of the total body surface area. The average patient age was 8.4 years. Of the 56 patients who received ciprofloxacin, 50 received the recommended dose. Biopsy specimens were assessed for quantitative bacteriology and antibiotic sensitivity. Radiologic review was conducted to examine for arthropathy. RESULTS: All patients showed unequivocal reduction in quantitative bacterial counts, and susceptibility to ciprofloxacin remained stable without the development of resistance. Of the 56 patients treated, 42 had a major reduction in their quantitative wound biopsies from 10(6) to less than 100 colonies per gram of tissue, while the remaining 14 were observed to have a 2- to 3-log decrease. No arthropathy was detected in any of the 56 patients receiving ciprofloxacin. Review of the patients' charts showed no documented adverse events associated with the use of ciprofloxacin. All patients survived their thermal injury and the complications associated with it without any untoward problems or complications of arthropathy. CONCLUSION: On the basis of these data, ciprofloxacin therapy in the treatment of immunosuppressed pediatric burn patients is efficacious and does not cause arthropathy. 相似文献
147.
A. E. Perez‐Ramos S. Villarreal‐Reyes C. Lepers A. Arvizu M. Muller G. I. Abib 《IEEJ Transactions on Electrical and Electronic Engineering》2015,10(Z1):S162-S164
Ultra wideband over fiber (UWBoF) systems have been proposed to extend wireless range and to interconnect stand‐alone UWB networks. These systems have focused on high‐data‐rate applications. However, UWB will be a key enabler for low‐data‐rate wireless sensor network (WSN) deployments. In this letter, a low‐cost and low‐complexity M‐ary pulse position modulation (PPM) impulse radio (IR)‐UWBoF system designed for WSNs applications is proposed. A spectral line‐suppressive convolutional code is used to achieve spectral line suppression in the power spectral density (PSD). Experimental results show that the system does not distort or add spectral lines to the IR‐UWB signal PSD transmitted over 30 km of a single‐mode fiber, thus demonstrating its feasibility to interconnect WSN deployments. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
148.
Jessica K. Campbell Jennifer L. King Matt Harmston Mary Ann Lila John W. Erdman Jr . 《Journal of food science》2006,71(4):S358-S363
ABSTRACT: Fruits and vegetables contain a variety of phytochemicals, including flavonoids, which have antioxidant and anticancer properties. The purpose of this study was to evaluate the antiproliferative effects and synergistic interactions of a variety of flavonoids in Hepa-1c1c7, a mouse liver cancer cell line, and LNCaP, a human prostate cancer cell line. Aglycone flavonoids, such as quercetin, kaempferol, and naringenin (at 12.5 to 50 μM), inhibited cancer cell proliferation in both cell lines in a dose dependent manner without cytotoxicity. In contrast, glycone flavonoids (rutin, quercetrin, and naringin) did not inhibit cell growth. Significant synergistic antiproliferative effects were demonstrated in both cancer cell lines when flavonoids were provided in combination treatments. These results suggest that combinations of flavonoids, which are naturally present in whole fruits and vegetables, are more effective in cancer cell growth inhibition than the individual flavonoids. 相似文献
149.
Beckjord Ellen Burke; Finney Rutten Lila J.; Arora Neeraj K.; Moser Richard P.; Hesse Bradford W. 《Canadian Metallurgical Quarterly》2008,27(2):249
Objective: Health communication can help reduce the cancer burden by increasing processing of information about health interventions. Negative affect is associated with information processing and may be a barrier to successful health communication. Design and Main Outcome Measures: We examined associations between negative affect and information processing at the population level. Symptoms of depression (6 items) and cancer worry (1 item) operationalized negative affect; attention to health information (5 items) and cancer information-seeking experiences (6 items) operationalized information processing. Results: Higher cancer worry was associated with more attention to health information (p 相似文献
150.
Keh‐Chyou Chang Yunior Hioe Maria G. Villarreal Jose M. Castro 《Polymer Engineering and Science》2009,49(12):2320-2328
Predicting the minimum safe cycle time in injection molding is complicated by the cyclic nature of the process. The mold thermal state changes with continuous molding until a quasi steady state is achieved. In the first part of these series, we presented and experimentally tested a simple approach to predict part and mold surface temperature during continuous molding. In this work, we evaluate the minimum frozen layer thickness required before the part can be demolded and how the growth of this frozen layer is affected as the mold thermal state changes with continuous molding cycles. Experiments are used to relate the minimum frozen layer thickness to dimensional stability. Based on these experiments, statistical tools are used to select an ejection criterion to obtain a minimum safe cooling time. We show that the ejection criteria should be adjusted depending on the precision required from the molded parts. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers 相似文献