全文获取类型
收费全文 | 211篇 |
免费 | 10篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 76篇 |
金属工艺 | 5篇 |
机械仪表 | 1篇 |
建筑科学 | 7篇 |
矿业工程 | 3篇 |
能源动力 | 3篇 |
轻工业 | 24篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 7篇 |
一般工业技术 | 21篇 |
冶金工业 | 10篇 |
原子能技术 | 7篇 |
自动化技术 | 50篇 |
出版年
2023年 | 3篇 |
2022年 | 11篇 |
2021年 | 4篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 15篇 |
2012年 | 14篇 |
2011年 | 24篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 10篇 |
2006年 | 7篇 |
2005年 | 11篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1978年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有221条查询结果,搜索用时 10 毫秒
21.
Alberto Gutierrez-Escolar Ana Castillo-Martinez Jose M. Gomez-Pulido Jose-Maria Gutierrez-Martinez Esteban Patricio Dominguez González-Seco Zlatko Stapic 《Energy Efficiency》2017,10(2):265-282
There are very few countries that have provisions addressing the energy efficiency of the whole street lighting system, such as Spain or the Netherlands. Nevertheless, there is not an agreement about how energy efficiency must be assessed. The Spanish Government contemplates it in the Royal Decree 1890/2008 with the goal of improving energy savings and efficiency. However, this has not obtained the expected results. Nowadays, energy efficiency of this kind of systems is assessed using a label. In the case of Spain, this label only assesses one magnitude. The contributions of this paper are two evaluation systems (kiviat diagram and pie chart) which assess five magnitudes: lamps, energy efficiency index, light pollution, renewable energy contribution, and harness of the luminous flux using dimming. After that, a survey was done to study several subjects: (1) if citizens are aware about the efficiency of street lighting systems, (2) whether the sample of colors used in the label is adequate, and (3) if our proposed systems could replace the current evaluation system. Finally, the paper finishes with the conclusions of the survey. 相似文献
22.
Ricardo Uauy Patricio Peirano Dennis Hoffman Patricia Mena David Birch Eileen Birch 《Lipids》1996,31(1):S167-S176
The basis for n-3 fatty acid essentiality in humans includes not only biochemical evidence but functional measures associated
with n-3 deficiency in human and nonhuman primates. Functional development of the retina and the occipital cortex are affected
by α-linolenic acid deficiency and by a lack of docosahexaenoic acid (DHA) in preterm infant formulas and, as reported more
recently, in term diets. Functional effects of n-3 supply on sleep-wake cycles and heart rate rhythms support the need for
dietary n-3 fatty acids during early development. Our results indicate that n-3 long-chain polyunsaturated fatty acids should
be considered provisionally essential for infant nutrition. DHA may also be required by individuals with inherited metabolic
defects in elongation and desaturation activity, such as patients with peroxisomal disorders and some forms of retinitis pigmentosa. 相似文献
23.
Natalia Landeros Patricio Gonzalez-Hormazabal Pablo Prez-Moreno Julio C. Tapia Lilian Jara 《International journal of molecular sciences》2022,23(23)
Variants in genes encoding for microRNAs have been associated with their deregulation in breast cancer (BC). Sequencing of microRNAs deregulated in BC was performed using DNA from Chilean patients with a strong family history and negative for mutations in BRCA1/BRCA2. Seventeen variants were identified, three of which were selected for a case-control association study: rs376491654 (miR-335), rs755634302 (miR-497), and rs190708267 (miR-155). For rs190708267 C>T, the heterozygous T allele was detected in four BC cases and absent in controls, while homozygous TT cases were not detected. Variants were modelled in silico, cloned in a plasmid, expressed in BC cell lines, and functional in vitro assays were performed. Overexpression of the miR-155-T allele increased mature miR-155-5p levels in both BC cell lines, suggesting that its presence alters pre-miR-155 processing. Moreover, BC cells overexpressing the miR-155-T allele showed increased proliferation, migration, and resistance to cisplatin-induced death compared to miR-155-C overexpressing cells. Of note, the 3′UTR of APC, GSK3β, and PPP1CA genes, all into the canonical Wnt signaling pathway, were identified as direct targets. APC and GSK3β mRNA levels decreased while PP1 levels increased. These results suggest a pathogenic role of the variant rs190708267 (miR-155) in BRCA 1/2 negative BC, conferring susceptibility and promoting traits of aggressiveness. 相似文献
24.
Sneana Hini April Rich Nicole V. Anayannis Stephanie Cabarcas-Petroski Laura Schramm Patricio I. Meneses 《International journal of molecular sciences》2022,23(18)
High-risk human papillomaviruses (HPV) are important agents, responsible for a large percentage of the 745,000 cases of head and neck squamous cell carcinomas (HNSCC), which were identified worldwide in 2020. In addition to being virally induced, tobacco and heavy alcohol consumption are believed to cause DNA damage contributing to the high number of HNSCC cases. Gene expression and DNA methylation differ between HNSCC based on HPV status. We used publicly available gene expression and DNA methylation profiles from the Cancer Genome Atlas and compared HPV positive and HPV negative HNSCC groups. We used differential gene expression analysis, differential methylation analysis, and a combination of these two analyses to identify the differences. Differential expression analysis identified 1854 differentially expressed genes, including PCNA, TNFRSF14, TRAF1, TRAF2, BCL2, and BIRC3. SYCP2 was identified as one of the top deregulated genes in the differential methylation analysis and in the combined differential expression and methylation analyses. Additionally, pathway and ontology analyses identified the extracellular matrix and receptor interaction pathway as the most altered between HPV negative and HPV positive HNSCC groups. Combining gene expression and DNA methylation can help in elucidating the genes involved in HPV positive HNSCC tumorigenesis, such as SYCP2 and TAF7L. 相似文献
25.
Poly(propylene) (PP) composites were prepared by using eggshell (ES) as filler and their mechanical properties were compared with those using talc (TA) and calcium carbonate (CC) of different grain sizes (X50). A decrease in impact strength and deformation at break with increase in filler content was observed. The PP composite with ES (X50 = 8.4 µm) was stiffer than those with CC (X50 = 0.7 µm). The hybrid composite PP‐ES‐TA showed a similar stiffness as the PP‐TA composites due to the similar morphology of TA (X50 = 0.5 µm) and ES, when TA was replaced up to 75 wt.‐% by ES. SEM study revealed evidence of improved interfacial bonding between PP and ES in theirs composites.
26.
Flanagan Constance A.; Cumsille Patricio; Gill Sukhdeep; Gallay Leslie S. 《Canadian Metallurgical Quarterly》2007,99(2):421
The developmental correlates of diffuse support for the polity and civic commitments were explored in a survey of 1,052 students (mean age = 14.96 years) from African American, Arab American, European American, and Latino American backgrounds. Results of structural equation modeling revealed that regardless of their age, gender, or ethnic background, youth were more likely to believe that America was a just society and to commit to democratic goals if they felt a sense of community connectedness, especially if they felt that their teachers practiced a democratic ethic at school. Discussion focuses on the civic purposes of education in inculcating a sense of identification with the polity in younger generations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
27.
Patricio Toro Raúl Quijada Mehrdad Yazdani-Pedram José Luis Arias 《Materials Letters》2007,61(22):4347-4350
Chicken eggshell (ES) is an industrial byproduct containing 95% calcium carbonate, and its disposal constitutes a serious environmental hazard. Different proportions of chicken eggshell as bio-filler for polypropylene (PP) composite were compared with different particle sizes and proportions of commercial talc and calcium carbonate fillers by tensile test. The Young's modulus (E) was improved with the increment of ES content, and this bio-filler was better than all types of carbonate fillers with different particle sizes used in this study. Although ES composites showed lower E values than talc composites, talc filler could be replaced by up to 75% with ES while maintaining a similar stiffness and E compared to the talc composites. Scanning electron microscopy showed an improved interfacial bonding on the tensile fractured surface. The improvement in the mechanical properties was attributed to a better ES/matrix interface related to the geometric ratio of the ES particles similar to talc particles. 相似文献
28.
The relationships among adolescent depressive symptoms and self-reported family cohesion, adaptability, satisfaction with family functioning, family structure, and social support received from family and friends were investigated in a sample of 93 families attending family therapy at an outpatient clinic. Results were in keeping with previous studies of nonclinical samples, in that family cohesion and family social support were inversely related to depression. In contrast to nonclinical samples, family characteristics were more strongly associated with depression among boys than among girls, and social support from friends did not act as a buffer against depression. The strongest predictor of depressive symptoms was adolescents' levels of satisfaction with the cohesiveness and adaptability in their families, suggesting the importance of subjective cognitive appraisal in the link between family functioning and depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
29.
Liberto Ercoli Patricio A.A. Laura Ricardo O. Grossi Gustavo Snchez Sarmiento 《Nuclear Engineering and Design》1985,88(3):377-381
The title problem is approximately solved by means of a variational formulation. It is shown that in the case of complicated boundary shapes of the cross section, the technique of conformal mapping is, sometimes, quite advantageous. The analytical predictions are compared with the results obtained by means of the finite element method and, in general, good engineering agreement is shown to exist. 相似文献
30.
Patricio A. A. Laura 《Nuclear Engineering and Design》1978,47(2):231-237
This paper compares analytical and finite element results for an unsteady heat-conduction problem in simply and doubly connected plates of regular polygonal shape. A numerical solution is obtained by means of the powerful finite element method and the results are shown to agree with an approximate conformal mapping-variational technique previously developed by the first author and coworkers. 相似文献