全文获取类型
收费全文 | 47817篇 |
免费 | 1178篇 |
国内免费 | 866篇 |
专业分类
电工技术 | 835篇 |
技术理论 | 1篇 |
综合类 | 142篇 |
化学工业 | 7897篇 |
金属工艺 | 3307篇 |
机械仪表 | 1770篇 |
建筑科学 | 996篇 |
矿业工程 | 196篇 |
能源动力 | 1730篇 |
轻工业 | 2719篇 |
水利工程 | 394篇 |
石油天然气 | 1507篇 |
武器工业 | 10篇 |
无线电 | 4876篇 |
一般工业技术 | 11806篇 |
冶金工业 | 7399篇 |
原子能技术 | 840篇 |
自动化技术 | 3436篇 |
出版年
2022年 | 333篇 |
2021年 | 560篇 |
2020年 | 470篇 |
2019年 | 557篇 |
2018年 | 874篇 |
2017年 | 883篇 |
2016年 | 977篇 |
2015年 | 749篇 |
2014年 | 1126篇 |
2013年 | 2786篇 |
2012年 | 1796篇 |
2011年 | 2331篇 |
2010年 | 1864篇 |
2009年 | 2138篇 |
2008年 | 1977篇 |
2007年 | 1979篇 |
2006年 | 1622篇 |
2005年 | 1447篇 |
2004年 | 1369篇 |
2003年 | 1258篇 |
2002年 | 1204篇 |
2001年 | 1240篇 |
2000年 | 1063篇 |
1999年 | 1124篇 |
1998年 | 2206篇 |
1997年 | 1731篇 |
1996年 | 1519篇 |
1995年 | 1030篇 |
1994年 | 811篇 |
1993年 | 798篇 |
1992年 | 620篇 |
1991年 | 596篇 |
1990年 | 542篇 |
1989年 | 506篇 |
1988年 | 376篇 |
1987年 | 410篇 |
1986年 | 368篇 |
1985年 | 387篇 |
1984年 | 314篇 |
1983年 | 308篇 |
1982年 | 305篇 |
1981年 | 301篇 |
1980年 | 350篇 |
1979年 | 345篇 |
1978年 | 298篇 |
1977年 | 418篇 |
1976年 | 629篇 |
1975年 | 308篇 |
1974年 | 292篇 |
1973年 | 314篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Molecular structure and granule morphology of native and heat‐moisture‐treated pinhão starch 下载免费PDF全文
Vania Z. Pinto Khalid Moomand Nathan L. Vanier Rosana Colussi Franciene A. Villanova Elessandra R. Zavareze Loong‐Tak Lim Alvaro R. G. Dias 《International Journal of Food Science & Technology》2015,50(2):282-289
Pinhão seed is an unconventional source of starch and the pines grow up in native forests of southern Latin America. In this study, pinhão starch was adjusted at 15, 20 and 25% moisture content and heated to 100, 110 and 120 °C for 1 h. A decrease in λ max (starch/iodine complex) was observed as a result of increase in temperature and moisture content of HMT. The ratio of crystalline to amorphous phase in pinhão starch was determined via Fourier transform infra red by taking 1045/1022 band ratio. A decrease in crystallinity occurred as a result of HMT. Polarised light microscopy indicated a loss of birefringence of starch granules under 120 °C at 25% moisture content. Granule size distribution was further confirmed via scanning electron microscopy which showed the HMT effects. These results increased the understanding on molecular and structural properties of HMT pinhão starch and broadened its food and nonfood industrial applications. 相似文献
3.
4.
5.
6.
Electrochemical impedance spectroscopy (EIS), anodic polarization and scanning electron microscopy techniques were used to investigate the damage mechanism in the transpassive potential region of AISI ... 相似文献
7.
Jasmin Kuhn Philipp M. Klein Nader Al Danaf Joel Z. Nordin Sren Reinhard Dominik M. Loy Miriam Hhn Samir El Andaloussi Don C. Lamb Ernst Wagner Yoshitsugu Aoki Taavi Lehto Ulrich Lchelt 《Advanced functional materials》2019,29(48)
Phosphorodiamidate morpholino oligomers (PMOs) are oligonucleotide analogs that can be used for therapeutic modulation of pre‐mRNA splicing. Similar to other classes of nucleic acid‐based therapeutics, PMOs require delivery systems for efficient transport to the intracellular target sites. Here, artificial peptides based on the oligo(ethylenamino) acid succinyl‐tetraethylenpentamine (Stp), hydrophobic modifications, and an azide group are presented, which are used for strain‐promoted azide‐alkyne cycloaddition conjugation with splice‐switching PMOs. By systematically varying the lead structure and formulation, it is determined that the type of contained fatty acid and supramolecular assembly have a critical impact on the delivery efficacy. A compound containing linolenic acid with three cis double bonds exhibits the highest splice‐switching activity and significantly increases functional protein expression in pLuc/705 reporter cells in vitro and after local administration in vivo. Structural and mechanistic studies reveal that the lipopeptide PMO conjugates form nanoparticles, which accelerate cellular uptake and that the content of unsaturated fatty acids enhances endosomal escape. In an in vitro Duchenne muscular dystrophy exon skipping model using H2K‐mdx52 dystrophic skeletal myotubes, the highly potent PMO conjugates mediate significant splice‐switching at very low nanomolar concentrations. The presented aminoethylene‐lipopeptides are thus a promising platform for the generation of PMO‐therapeutics with a favorable activity/toxicity profile. 相似文献
8.
9.
10.
Based on the phase transformation theories, especially the T0 concept of bainite transformation, alloy optimisation of bainitic steel with carbides has been carried out aiming at the produce of plastic mould with large cross-section. The effect of manganese and silicon on proeutectoid ferrite and bainite transformation is explored by dilatometric analysis, XRD and different microscopy techniques. The results show that after the alloy optimisation, the transformation of proeutectoid ferrite is suppressed and when the cooling rate is lower than 0·1°C?s??1, the new lower bainite transformation appears by decreasing carbon capacity of austenite and promoting carbide precipitation. Industrial production proves that the optimised alloy SDP1 can meet the demand for the plastic mould with the thickness of 1050?mm. 相似文献