全文获取类型
收费全文 | 2091篇 |
免费 | 25篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 91篇 |
金属工艺 | 9篇 |
机械仪表 | 5篇 |
建筑科学 | 14篇 |
矿业工程 | 1篇 |
能源动力 | 14篇 |
轻工业 | 58篇 |
水利工程 | 14篇 |
无线电 | 70篇 |
一般工业技术 | 110篇 |
冶金工业 | 1634篇 |
原子能技术 | 14篇 |
自动化技术 | 79篇 |
出版年
2023年 | 5篇 |
2022年 | 13篇 |
2021年 | 16篇 |
2020年 | 28篇 |
2019年 | 23篇 |
2018年 | 12篇 |
2017年 | 11篇 |
2016年 | 14篇 |
2015年 | 10篇 |
2014年 | 15篇 |
2013年 | 24篇 |
2012年 | 15篇 |
2011年 | 38篇 |
2010年 | 19篇 |
2009年 | 18篇 |
2008年 | 20篇 |
2007年 | 19篇 |
2006年 | 16篇 |
2005年 | 19篇 |
2004年 | 12篇 |
2003年 | 17篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 16篇 |
1999年 | 35篇 |
1998年 | 473篇 |
1997年 | 280篇 |
1996年 | 189篇 |
1995年 | 147篇 |
1994年 | 96篇 |
1993年 | 92篇 |
1992年 | 28篇 |
1991年 | 25篇 |
1990年 | 17篇 |
1989年 | 11篇 |
1988年 | 16篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 13篇 |
1983年 | 12篇 |
1982年 | 7篇 |
1981年 | 21篇 |
1980年 | 21篇 |
1979年 | 5篇 |
1978年 | 9篇 |
1977年 | 62篇 |
1976年 | 111篇 |
1974年 | 4篇 |
1973年 | 6篇 |
1972年 | 3篇 |
排序方式: 共有2116条查询结果,搜索用时 15 毫秒
1.
2.
S.K. Vimala Bharathi M. Maria Leena J.A. Moses C. Anandharamakrishnan 《International Journal of Food Science & Technology》2020,55(3):1238-1245
The usage of cling wraps is emerging as an easy and cost-effective approach to protect fresh-cut fruits and vegetables from dust, whilst improving visual appeal on retail counters. This study focused on developing an alternate, protein-based packaging material as a food grade cling wrap for food packaging applications. Zein-based cling wraps were produced, and their physical and mechanical characteristics were evaluated and compared with conventionally used chitosan biopolymer films and commercial synthetic polymer films. Antioxidant potential of the prepared films was studied, and the effectiveness of the developed films as anti-browning cling wraps was evaluated using studies conducted on fresh-cut apple slices at ambient conditions. Anti-browning effects were in par with polymeric counterparts; however, zein cling wraps could better prevent weight loss in apple slices. Zein-based films can be adopted as biodegradable food grade cling wraps as an alternative to chitosan and synthetic polymeric materials. 相似文献
3.
X. Gong W. Ma J.C. Ostrowski K. Bechgaard G.C. Bazan A.J. Heeger S. Xiao D. Moses 《Advanced functional materials》2004,14(4):393-397
The electronic properties, carrier injection, and transport into poly(9,9‐dioctylfluorene) (PFO), PFO end‐capped with hole‐transporting moieties (HTM), PFO–HTM, and PFO end‐capped with electron‐transporting moieties (ETM), PFO–ETM, were investigated. The data demonstrate that charge injection and transport can be tuned by end‐capping with HTM and ETM, without significantly altering the electronic properties of the conjugated backbone. End‐capping with ETM resulted in more closely balanced charge injection and transport. Single‐layer electrophosphorescent light‐emitting diodes (LEDs), fabricated from PFO, PFO–HTM and PFO–ETM as hosts and tris[2,5‐bis‐2′‐(9′,9′‐dihexylfluorene)pyridine‐κ2NC3′]iridium(III ), Ir(HFP)3 as the guest, emitted red light with brightnesses of 2040 cd m–2, 1940 cd m–2 and 2490 cd m–2 at 290 mA cm–2 (16 V) and with luminance efficiencies of 1.4 cd A–1, 1.4 cd A–1 and 1.8 cd A–1 at 4.5 mA cm–2 for PFO, PFO–HTM, and PFO–ETM, respectively. 相似文献
4.
We characterize the meander of re-entrant excitation in a model of a sheet of mammalian ventricular tissue, and its control by resonant drift under feedback driven stimulation. The Oxsoft equations for excitability in a guinea pig single ventricular cell were incorporated in a two dimensional reaction-diffusion system to model homogeneous, isotropic tissue with a plane wave conduction velocity of 0.35 m s-1. Re-entrant spiral wave solutions have a spatially extended transient motion (linear core) that settles down into rotation with an irregular period of 100-110 ms around an irregular, multi-lobed spiky core. In anisotropic tissue this would appear as a linear conduction block. The typical velocity of drift of the spiral wave induced by low amplitude resonant forcing is 0.4 cm s-1. 相似文献
5.
SA Balakirev VI Tsygankin AV Ivanov VI Atroshchenko AN Ianovski? M Sarfundin 《Canadian Metallurgical Quarterly》1997,43(4):445-447
The report deals with the development of procedures, evaluation of laser application and prevention of complications involved in intensive chemoradiation therapy of neoplasms of hemopoietic and lymphoid tissue in childhood. The clinical data on 548 patients, aged 2 months-15 years, with leukemia and solid tumor were evaluated. Laser application for treatment of different complications of chemoradiation therapy of pediatric leukemia proved a valuable innovation. It had a pronounced antiinflammatory and analgetic effect, promoted tissue regeneration processes and cut down the duration of complication treatment drastically. 相似文献
6.
7.
AV Pensler 《Canadian Metallurgical Quarterly》1998,19(4):387-90, 392-4, 396; quiz 398
8.
9.
10.
AV Stefano LF Canosa JL D'Eramo O Fridman JM Affanni GM Somoza 《Canadian Metallurgical Quarterly》1997,118(3):335-345
Gonadotropin-releasing hormone (GnRH) molecular variants in the brain and pituitary gland of pejerrey, Odontesthes bonariensis (Atheriniformes), were characterized by gradient reverse phase high performance liquid chromatography (RP-HPLC). Eluted fractions were tested in radioimmunoassays with different antisera. The results show that the brain extract contains three forms of GnRH: one is immunologically and chromatographically similar to cIIGnRH (chicken II), and another is similar to sGnRH (salmon). A third GnRH appears to be chromatographic and immunologically different from the nine other known forms of the vertebrate hormone. This is the only variant present in the pituitary gland. 相似文献