全文获取类型
收费全文 | 345624篇 |
免费 | 5783篇 |
国内免费 | 753篇 |
专业分类
电工技术 | 6753篇 |
综合类 | 646篇 |
化学工业 | 55058篇 |
金属工艺 | 11086篇 |
机械仪表 | 9577篇 |
建筑科学 | 9830篇 |
矿业工程 | 1059篇 |
能源动力 | 9362篇 |
轻工业 | 34778篇 |
水利工程 | 2829篇 |
石油天然气 | 3750篇 |
武器工业 | 8篇 |
无线电 | 42169篇 |
一般工业技术 | 66176篇 |
冶金工业 | 60855篇 |
原子能技术 | 5736篇 |
自动化技术 | 32488篇 |
出版年
2021年 | 3123篇 |
2020年 | 2246篇 |
2019年 | 2795篇 |
2018年 | 4620篇 |
2017年 | 4422篇 |
2016年 | 4726篇 |
2015年 | 3576篇 |
2014年 | 5708篇 |
2013年 | 16781篇 |
2012年 | 9113篇 |
2011年 | 12352篇 |
2010年 | 9618篇 |
2009年 | 10713篇 |
2008年 | 11389篇 |
2007年 | 11259篇 |
2006年 | 9895篇 |
2005年 | 8958篇 |
2004年 | 8746篇 |
2003年 | 8418篇 |
2002年 | 8193篇 |
2001年 | 8206篇 |
2000年 | 7755篇 |
1999年 | 8077篇 |
1998年 | 18430篇 |
1997年 | 13465篇 |
1996年 | 10603篇 |
1995年 | 8357篇 |
1994年 | 7624篇 |
1993年 | 7298篇 |
1992年 | 5609篇 |
1991年 | 5306篇 |
1990年 | 5225篇 |
1989年 | 5055篇 |
1988年 | 4906篇 |
1987年 | 4136篇 |
1986年 | 4235篇 |
1985年 | 5053篇 |
1984年 | 4588篇 |
1983年 | 4282篇 |
1982年 | 3864篇 |
1981年 | 4026篇 |
1980年 | 3680篇 |
1979年 | 3655篇 |
1978年 | 3438篇 |
1977年 | 4027篇 |
1976年 | 5096篇 |
1975年 | 2973篇 |
1974年 | 2807篇 |
1973年 | 2819篇 |
1972年 | 2320篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
1.
One specific class of non-linear evolution equations, known as the Tzitzéica-type equations, has received great attention from a group of researchers involved in non-linear science. In this article, new exact solutions of the Tzitzéica-type equations arising in non-linear optics, including the Tzitzéica, Dodd–Bullough–Mikhailov and Tzitzéica–Dodd–Bullough equations, are obtained using the expa function method. The integration technique actually suggests a useful and reliable method to extract new exact solutions of a wide range of non-linear evolution equations. 相似文献
2.
Thomas Fibiger 《Material Religion》2019,15(2):204-220
AbstractThis article discusses different approaches to materiality and material expressions of cultural identity in contemporary Bahrain, a small Arab Gulf state. Various Islamic traditions have different understandings of materiality and its ontological qualities. In the contemporary Gulf this difference is often understood as a sectarian difference between Sunni and Shia Muslims, a division that has gained increasing political importance in recent years. In this article I discuss how these traditions view materiality in religion, in particular focusing on the role of material mediation for Shia Muslims, exemplified by the use and meaning of the turba prayer stone. With this as a point of departure I discuss two other forms of materiality—political graffiti and martyr images—that in the wake of the uprising in 2011 have also been imbued with sectarian meanings, but where this is less clear. I therefore argue that vernacular understandings of material culture show ambiguous identifications that challenge the clear dichotomies with which people—locally and analytically —often operate. 相似文献
3.
4.
5.
6.
7.
Zenan Yu Julian Moore Jean Calderon Lei Zhai Jayan Thomas 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(39):5289-5295
Cable‐shaped supercapacitors (SCs) have recently aroused significant attention due to their attractive properties such as small size, lightweight, and bendability. Current cable‐shaped SCs have symmetric device configuration. However, if an asymmetric design is used in cable‐shaped supercapacitors, they would become more attractive due to broader cell operation voltages, which results in higher energy densities. Here, a novel coil‐type asymmetric supercapacitor electrical cable (CASEC) is reported with enhanced cell operation voltage and extraordinary mechanical‐electrochemical stability. The CASECs show excellent charge–discharge profiles, extraordinary rate capability (95.4%), high energy density (0.85 mWh cm−3), remarkable flexibility and bendability, and superior bending cycle stability (≈93.0% after 4000 cycles at different bending states). In addition, the CASECs not only exhibit the capability to store energy but also to transmit electricity simultaneously and independently. The integrated electrical conduction and storage capability of CASECS offer many potential applications in solar energy storage and electronic gadgets. 相似文献
8.
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
9.
10.