全文获取类型
收费全文 | 1018篇 |
免费 | 56篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 277篇 |
金属工艺 | 4篇 |
机械仪表 | 17篇 |
建筑科学 | 67篇 |
矿业工程 | 3篇 |
能源动力 | 22篇 |
轻工业 | 158篇 |
水利工程 | 7篇 |
石油天然气 | 3篇 |
无线电 | 37篇 |
一般工业技术 | 129篇 |
冶金工业 | 231篇 |
原子能技术 | 4篇 |
自动化技术 | 113篇 |
出版年
2023年 | 15篇 |
2022年 | 68篇 |
2021年 | 76篇 |
2020年 | 26篇 |
2019年 | 28篇 |
2018年 | 30篇 |
2017年 | 37篇 |
2016年 | 35篇 |
2015年 | 18篇 |
2014年 | 30篇 |
2013年 | 58篇 |
2012年 | 55篇 |
2011年 | 54篇 |
2010年 | 53篇 |
2009年 | 50篇 |
2008年 | 61篇 |
2007年 | 35篇 |
2006年 | 23篇 |
2005年 | 23篇 |
2004年 | 22篇 |
2003年 | 24篇 |
2002年 | 26篇 |
2001年 | 12篇 |
2000年 | 7篇 |
1999年 | 11篇 |
1998年 | 12篇 |
1997年 | 8篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1994年 | 12篇 |
1993年 | 8篇 |
1992年 | 13篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1970年 | 3篇 |
1964年 | 2篇 |
排序方式: 共有1074条查询结果,搜索用时 15 毫秒
131.
Dr. Francesco A. Greco Dr. Elisa Albini Dr. Alice Coletti Dr. Daniela Dolciami Prof. Andrea Carotti Dr. Ciriana Orabona Prof. Ursula Grohmann Prof. Antonio Macchiarulo 《ChemMedChem》2019,14(24):2084-2092
Indoleamine 2,3-dioxygenase 1 (IDO1) catalyzes the oxidative cleavage of l -Tryptophan (l -Trp) to yield N-formyl-kynurenine in the first and rate limiting step of the kynurenine pathway. Bioactive metabolites, involved in the regulation of important immunological responses and neurological processes, are then produced by downstream enzymes along the pathway. Inhibitors of IDO1 are being designed and developed as therapeutic agents for immuno-oncology. In this work, we investigated the molecular recognition path of l -Trp to IDO1, integrating biophysical methods with supervised molecular dynamics (suMD) and mutagenesis experiments. Results allowed disclosing for the first time high and low dissociation constants of l -Trp to IDO1, and the presence of a metastable interaction site located at the upper part of a channel whose borders are defined by the EF-loop and the C-terminal part of the JK-loop. Collectively, our results provide new clues for the design of next-generation IDO1 ligands. 相似文献
132.
André F. Soares Alice R. Honorio Diana C. Nunes de Lima Alline A. L. Tribst 《International Journal of Food Science & Technology》2021,56(9):4428-4433
This study characterised the main sweet beverages and food products marketed in Brazil regarding (i) the addition of sugar/sweeteners, (ii) nutritional profile and (iii) sugar claims. Results revealed that most of the beverages had added sweeteners, while food products were mainly sweetened with sugar. Moreover, >90% of the powdered products had added sweeteners. ‘Zero sugar’ (46%) and ‘light’ (55%) were the most common sugar claims in sugar-free and reduced-sugar products, respectively. Powdered products, soya drinks and baked products included claims less frequently. Regarding the nutritional profile, beverages with sugar substitution had a proportionally greater reduction in the content of carbohydrates and calories (up to 99%, for both) in relation to food (<82% and <85%, respectively). The results suggest that reducing sugar in solid foods remains a greater challenge than in beverages and that this reduction has less impact on the final energy density of foods. 相似文献
133.
134.
Marcus A. OMara Sean P. Ogilvie Matthew J. Large Aline Amorim Graf Anne C. Sehnal Peter J. Lynch Jonathan P. Salvage Izabela Jurewicz Alice A. K. King Alan B. Dalton 《Advanced functional materials》2020,30(32)
Here, an approach is presented to incorporate graphene nanosheets into a silicone rubber matrix via solid stabilization of oil‐in‐water emulsions. These emulsions can be cured into discrete, graphene‐coated silicone balls or continuous, elastomeric films by controlling the degree of coalescence. The electromechanical properties of the resulting composites as a function of interdiffusion time and graphene loading level are characterized. With conductivities approaching 1 S m?1, elongation to break up to 160%, and a gauge factor of ≈20 in the low‐strain linear regime, small strains such as pulse can be accurately measured. At higher strains, the electromechanical response exhibits a robust exponential dependence, allowing accurate readout for higher strain movements such as chest motion and joint bending. The exponential gauge factor is found to be ≈20, independent of loading level and valid up to 80% strain; this consistent performance is due to the emulsion‐templated microstructure of the composites. The robust behavior may facilitate high‐strain sensing in the nonlinear regime using nanocomposites, where relative resistance change values in excess of 107 enable highly accurate bodily motion monitoring. 相似文献
135.
Alice E. Snape Jody L. Turner Hassan M. El-Dessouky Mohamed N. Saleh Hannah Tew Richard J. Scaife 《Applied Composite Materials》2018,25(4):735-746
The work presented here focusses on the developments in the stabilising and trimming of 3D woven preforms. Dry fibre preforms are notoriously difficult to trim; once a fabric is cut, it loses its edge stability and consequently the fabric frays. The result is an unstable fabric which can easily be displaced/ distorted prior to composite manufacturing. In this work, three stabilisation and three trimming techniques were investigated. Of the stabilisation techniques these included powder binder, thermoplastic binder yarn (activated to give fabric stabilization); and polyester stitching. The stabilised fabrics were trimmed to near-net-shape using different trimming techniques. The trimming techniques investigated were laser, clicker press and ultrasonic knife. Each stabilisation method was trialled with each trimming method to assess the most suitable combination. The assessment of quality and suitability was made by observing the level of stabilisation, amount of fraying fibres, quality of the cut, ease of application and repeatability of the process. This paper details the assessments made for each combination alongside practical application conclusions. The key findings were; cutting by means of a laser is capable of sealing the fabric edges, producing high edge quality. Stitching as a method of stabilising is not sufficient in preventing fibres from moving during the cutting process, hence producing an unclean cut. 相似文献
136.
In this paper, a single-item capacitated lot-sizing problem in a flow-shop system with energy consideration is studied. The planning horizon is defined by a set of periods where each one is characterised by a length, an allowed maximal power, an electricity price, a power price and a demand. The objective is to determine the quantities to be produced by each machine at each period while minimising the production cost in terms of electrical, inventory, set-up and power required costs. For medium- and large-scale problems, lot-sizing problems are hard to solve. Therefore, in this study, two heuristics are developed to solve this problem in a reasonable time. To evaluate the performances of these heuristics, computational experiments are presented and numerical results are discussed and analysed. 相似文献
137.
Xiaofang Jia Kosuke Minami Koichiro Uto Alice Chinghsuan Chang Jonathan P. Hill Jun Nakanishi Katsuhiko Ariga 《Advanced materials (Deerfield Beach, Fla.)》2020,32(4):1905942
There is a growing interest in the development of dynamic adaptive biomaterials for regulation of cellular functions. However, existing materials are limited to two-state switching of the presentation and removal of cell-adhesive bioactive motifs that cannot emulate the native extracellular matrix (ECM) in vivo with continuously adjustable characteristics. Here, tunable adaptive materials composed of a protein monolayer assembled at a liquid–liquid interface are demonstrated, which adapt dynamically to cell traction forces. An ultrastructure transition from protein monolayer to hierarchical fiber occurs through interfacial jamming. Elongated fibronectin fibers promote formation of elongated focal adhesion structures, increase focal adhesion kinase activation, and enhance neuronal differentiation of stem cells. Cell traction force results in spatial rearrangement of ECM proteins, which feeds back to alter stem cell fate. The reported biomimetic adaptive liquid interface enables dynamic control of stem cell behavior and has potential translational applications. 相似文献
138.
Auditory perception based system for age classification and estimation using dynamic frequency sound
Ilyas Muhammad Othmani Alice Nait-ali Amine 《Multimedia Tools and Applications》2020,79(29-30):21603-21626
Multimedia Tools and Applications - Human age is a crucial factor in social interaction. It determines the way we interact with others. It is also a relevant forensic issue that can provide helpful... 相似文献
139.
Alice S. Tempel 《Journal of chemical ecology》1982,8(10):1289-1298
Techniques used in different biological and industrial fields for the detection and quantification of tannin compounds in plants are discussed. Emphasis is placed on the choice of method for ecological investigations, which may benefit from the use of a method that measures relative astringency of plant extracts at reduced costs in time and equipment, permitting the analysis of larger samples than may be feasible with more sophisticated analytical techniques. 相似文献
140.
Gerhard Gries Regine Gries Alice L. Perez Lilliana M. Gonzales Harold D. Pierce Jr. A. Cameron Oehlschlager Marc Rhainds Mesmer Zebeyou Brou Kouame 《Journal of chemical ecology》1994,20(4):889-897
Small trunk pieces of a freshly felled 10-year-old oil palm,Elaeis quineensis (Jacq.), were placed in a modified Nalgene desiccator, and volatiles captured for six days on Porapak Q. Gas chromatographic (GC) analysis of Porapak-Q-trapped volatiles with both flame ionization (FID) and electroantennographic detection (EAD) using male or femaleR. phoenicis antennae revealed several EAD-active compounds. They were identified as: ethyl acetate, ethyl propionate, isobutyl propionate, ethyl butyrate, and ethyl isobutyrate. In field experiments in the La Me Research Station, Côte d'Ivoire, ethyl propionate (50 mg/24 hr) but not all esters combined (50 mg/24 hr each) significantly increased capture ofR. phoenicis in pheromone-baited (3 mg/24 hr) traps. One kilogram of 1- to 3-day-old palm tissue was significantly more effective than ethyl propionate in enhancing pheromone attraction. Superior attraction of palm tissue may be attributed to additional as yet unknown semiochemicals. Alternatively, release rates and/or ratios of synthetic volatiles differed from those of palm tissue at peak attraction. 相似文献