全文获取类型
收费全文 | 495篇 |
免费 | 22篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 2篇 |
综合类 | 3篇 |
化学工业 | 114篇 |
金属工艺 | 4篇 |
机械仪表 | 6篇 |
建筑科学 | 24篇 |
矿业工程 | 2篇 |
能源动力 | 8篇 |
轻工业 | 130篇 |
水利工程 | 5篇 |
石油天然气 | 3篇 |
无线电 | 13篇 |
一般工业技术 | 74篇 |
冶金工业 | 77篇 |
原子能技术 | 1篇 |
自动化技术 | 53篇 |
出版年
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 5篇 |
2019年 | 9篇 |
2018年 | 10篇 |
2017年 | 11篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 16篇 |
2013年 | 24篇 |
2012年 | 25篇 |
2011年 | 43篇 |
2010年 | 20篇 |
2009年 | 15篇 |
2008年 | 28篇 |
2007年 | 25篇 |
2006年 | 18篇 |
2005年 | 17篇 |
2004年 | 17篇 |
2003年 | 15篇 |
2002年 | 11篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 10篇 |
1997年 | 10篇 |
1996年 | 4篇 |
1995年 | 9篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 2篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1971年 | 2篇 |
排序方式: 共有519条查询结果,搜索用时 15 毫秒
101.
Schippers Gerard M. ; Lammers Sylvia M. M. ; Schaap Cas P. D. R. 《Canadian Metallurgical Quarterly》1993,7(1):76
Review of book: Contributions to the Psychology of Addiction, Gerard M. Schippers, Sylvia M. M. Lammers and Cas P. D. R. Schaap, (Eds.), Amsterdam/Lisse: Swets & Zeitlinger, 1991, 157 pp., ISBN 90-265-1217-1. Reviewed by Arvid Amundsen. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
102.
McLain SE Dolgos MR Tennant DA Turner JF Barnes T Proffen T Sales BC Bewley RI 《Nature materials》2006,5(7):561-566
Fluoride phases that contain the spin-1/2 4d9 Ag(II) ion have recently been predicted to have interesting or unusual magnetochemistry, owing to their structural similarity to the 3d9 Cu(II) cuprates and the covalence associated with this unusual oxidation state of silver. Here we present a comprehensive study of structure and magnetism in the layered Ag(II) fluoride Cs2AgF4, using magnetic susceptometry, inelastic neutron scattering techniques and both X-ray and neutron powder diffraction. We find that this material is well described as a two-dimensional ferromagnet, in sharp contrast to the high-T(C) cuprates and a previous report in the literature. Analyses of the structural data show that Cs2AgF4 is orbitally ordered at all temperatures of measurement. Therefore, we suggest that orbital ordering may be the origin of the ferromagnetism we observe in this material. 相似文献
103.
Berninger Virginia W.; Vaughan Katherine; Abbott Robert D.; Brooks Allison; Abbott Sylvia P.; Rogan Laura; Reed Elizabeth; Graham Steve 《Canadian Metallurgical Quarterly》1998,90(4):587
Poor spellers in 2nd grade (n?=?128) participated in 24 20-min sessions that included (a) direct instruction in the alphabet principle (most frequent phoneme-spelling connections); (b) modeling of different approaches, singly and in combination, for developing connections between spoken and written words for 48 words ordered by sound-spelling predictability; and (c) practice in composing. Results of this multilayered intervention showed that (a) more than 1 way of developing sound-spelling connections is effective in teaching spelling but that after training in the alphabet principle, combining whole word and onset-rime training is most effective in achieving transfer of the alphabet principle across word contexts; (b) functional spelling units of not only a single letter but also 2 or more letters are important in beginning spelling; and (c) training in spelling transfers to composition and word recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
105.
Castillo Linda G.; Cano Miguel A.; Chen Sylvia W.; Blucker Ryan T.; Olds Tori S. 《Canadian Metallurgical Quarterly》2008,15(1):43
This study examined the impact of family conflict and intragroup marginalization on acculturative stress in 188 bicultural Latino college students. Results showed that low parental income, low acculturation, perceived family conflict, and perceived intragroup marginalization were related to higher acculturative stress for participants. Intragroup marginalization accounted for a statistically significant proportion of the variance in acculturative stress after all variables were controlled. The findings emphasize the need to recognize culture-specific stressors of college students. Implications for mental health providers are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
106.
Sylvia A Mitchell Helen N Asemota Mohammad H Ahmad 《Journal of the science of food and agriculture》1995,67(4):541-550
Factors such as inorganic ammonium, growth regulator supplements, propagule type and subculture period affecting the in-vitro establishment of Dioscorea cayenensis and D trifida have been examined. The results indicate that for D cayenensis, transfer of whole plantlets to fresh initiation media prior to cutting into nodal segments and transfer to establishment media was beneficial. Addition of 800 mg litre?1 NH4NO3 to basal medium (BM) containing 0.5 mg litre?1benzylamino purine (BAP) caused a significant improvement in nodal numbers and resulted ir. 11.8 propagules per original explant after 8 weeks or 184.1 propagules after 16 weeks in-vitro. Rapid establishment of D trifida cv Short Neck Yampie depended on the original explant source. Explants obtained from small tuber vines grew faster on establishment than those obtained from leafy cuttings. Initiation on BM supplemented with 0.5 mg litre?1 kinetin (BM0.5K) and establishment on BM supplemented with 0.5 mg litre?1 BAP (BM0.5BAP) produced the optimum result for the vines obtained from small tubers (24.0 propagules after 8 weeks of culture). For explants obtained from leafy cuttings, initiation on BM0.5BAP and establishment on BM0.5K gave optimum results (15.8). Quick establishment of initiated plantlets shown by increased shoot response and high multiplication rates were achieved in this study. 相似文献
107.
108.
Serrano-Garcia William Jayathilaka Wanasinghe Arachchige Dumith Madushanka Chinnappan Amutha Tran Thang Quyet Baskar Chinnappan Thomas Sylvia Wilson Ramakrishna Seeram 《中国科学:技术科学(英文版)》2019,62(6):895-902
In the present review, we have selected advances in electrospinning nanofibers that we envision to be embedded in textiles and wearables. These nanofibers have been proven to be excellent options for applications such as power generation, sensing, and communication. Their similitude with already known woven meshes makes these fibers perfect for electronically active textiles.These fibers offer well known characteristics such as mechanical flexibility, high surface area-to-volume ratio, light weight and can be tuned by carefully selecting the active materials in the precursor solution. Here we will discuss polymers with electroactive, piezoelectric, triboelectric and their composites that have been used in fiber structures by using the electrospinning technique. 相似文献
109.
Lennart Nicke Philip Horx Ronny Müller Dr. Sylvia Els-Heindl Prof. Dr. Armin Geyer 《Chembiochem : a European journal of chemical biology》2021,22(2):330-335
A generalized synthetic strategy is proposed here for the synthesis of asymmetric β-indoylated amino acids by 8-aminoquinoline (8AQ)-directed C(sp3)-H functionalization of suitably protected precursors. Peptides containing one of the four stereoisomers of (indol-3-yl)-3-phenylalanine at position 2 of the parent peptide KwFwLL-NH2 (w=d -Trp) cover a wide range of activities as ghrelin receptor inverse agonists, among them the most active described until now. This application exemplarily shows how β-indoylated amino acids can be used for the systematic variation of the position of an indole group in a bioactive peptide. 相似文献
110.
Juliana Starling Ângelo de Fátima Maria Sylvia Silva Dantas 《Journal of Adhesion Science and Technology》2013,27(24):2393-2401
The adhesion between polymer adhesives and dentin involves the removal of minerals, by acid etching the dentin surface, to allow for monomer infiltration among collagen fibrils. However, instability within this hybrid layer has been observed, which may partially be attributed to a slow degradation of the collagen not protected by the adhesive. The objective of this work was to improve the stability of the hybrid layer by increasing the interactions between adhesives and collagen through the incorporation of a monomer that behaves reactively toward collagen in the adhesive. In this work, a control adhesive was prepared based on a chemical formulation containing Bis-GMA and HEMA, and was modified by incorporating different concentrations (5, 10, and 20%) of NSA (N-acryloxysuccinimide), which contains an ester group capable of interacting with primary amine. These experimental adhesives were applied to bovine dentin for the in vitro production of the interfacial layer, which was analyzed by Raman spectroscopy and scanning electron microscopy. The obtained results showed that it was possible to incorporate the NSA monomer into the adhesive up to a maximum concentration of 10%. The presence of amide bonds in the Raman spectra, as well as the presence of a large amount of experimental adhesive within the interfacial layer, as indicated in the scanning electron microscopy images, may suggest the occurrence of chemical interactions between polymers and dentin collagen fibrils. These interfacial chemical interactions involving dental adhesives and dentin can be an important tool in protecting the hybrid layer from degradation. 相似文献