全文获取类型
收费全文 | 963篇 |
免费 | 58篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 262篇 |
金属工艺 | 15篇 |
机械仪表 | 16篇 |
建筑科学 | 16篇 |
能源动力 | 41篇 |
轻工业 | 197篇 |
水利工程 | 3篇 |
石油天然气 | 3篇 |
无线电 | 83篇 |
一般工业技术 | 148篇 |
冶金工业 | 74篇 |
原子能技术 | 4篇 |
自动化技术 | 150篇 |
出版年
2023年 | 9篇 |
2022年 | 37篇 |
2021年 | 33篇 |
2020年 | 22篇 |
2019年 | 38篇 |
2018年 | 32篇 |
2017年 | 34篇 |
2016年 | 35篇 |
2015年 | 35篇 |
2014年 | 34篇 |
2013年 | 70篇 |
2012年 | 56篇 |
2011年 | 75篇 |
2010年 | 46篇 |
2009年 | 57篇 |
2008年 | 60篇 |
2007年 | 30篇 |
2006年 | 46篇 |
2005年 | 37篇 |
2004年 | 36篇 |
2003年 | 26篇 |
2002年 | 21篇 |
2001年 | 18篇 |
2000年 | 10篇 |
1999年 | 11篇 |
1998年 | 22篇 |
1997年 | 14篇 |
1996年 | 13篇 |
1995年 | 11篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 9篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1021条查询结果,搜索用时 0 毫秒
121.
Tony Salvador John W. Sherry Alvaro E. Urrutia 《Information Technology for Development》2013,19(1):77-95
About 10% of the world has access to information and communication technologies (ICTs). Telecenters and cyber cafés are one prevalent way to increase access. This paper suggests increasing access through currently existing, local businesses where people already gather and where proprietors already posses existing business relationships with suppliers and customers. This paper questions the prevailing emphasis on the “cyber'' characteristics of access, e.g., computing and internet access as is currently known, and attempts to refocus the conversation by considering computing and access in the context of the “café,” e.g., as public life in the sense of Habermas, which permits an in situ evolution of relevant access. This analysis is based on extant literature and direct ethnographic research in several public places in six countries. We offer example design perspectives based on a reflection of “third places” as inspiration for appropriate innovation in the provision of computing and communications. © 2005 Wiley Periodicals, Inc. 相似文献
122.
123.
Ana Santos-Gmez Federico Miguez-Cabello Natalia Juli-Palacios Deyanira García-Navas Víctor Soto-Insuga Juan J. García-Peas Patricia Fuentes Salvador Ibez-Mic Laura Cuesta Ramn Cancho Patricia Andreo-Lillo Gema Gutirrez-Aguilar Olga Alonso-Luengo Ignacio Mlaga Antonio Hedrera-Fernndez ngels García-Cazorla David Soto Mireia Olivella Xavier Altafaj 《International journal of molecular sciences》2021,22(23)
Background: GRIN-related disorders (GRD), the so-called grinpathies, is a group of rare encephalopathies caused by mutations affecting GRIN genes (mostly GRIN1, GRIN2A and GRIN2B genes), which encode for the GluN subunit of the N-methyl D-aspartate (NMDA) type ionotropic glutamate receptors. A growing number of functional studies indicate that GRIN-encoded GluN1 subunit disturbances can be dichotomically classified into gain- and loss-of-function, although intermediate complex scenarios are often present. Methods: In this study, we aimed to delineate the structural and functional alterations of GRIN1 disease-associated variants, and their correlations with clinical symptoms in a Spanish cohort of 15 paediatric encephalopathy patients harbouring these variants. Results: Patients harbouring GRIN1 disease-associated variants have been clinically deeply-phenotyped. Further, using computational and in vitro approaches, we identified different critical checkpoints affecting GluN1 biogenesis (protein stability, subunit assembly and surface trafficking) and/or NMDAR biophysical properties, and their association with GRD clinical symptoms. Conclusions: Our findings show a strong correlation between GRIN1 variants-associated structural and functional outcomes. This structural-functional stratification provides relevant insights of genotype-phenotype association, contributing to future precision medicine of GRIN1-related encephalopathies. 相似文献
124.
Salvador Alfaro Manuel Arruebo Joaquín Coronas Miguel Menndez Jesús Santamaría 《Microporous and mesoporous materials》2001,50(2-3):195-200
Zeolite MFI membranes were successfully prepared on both alumina and stainless steel tubular supports by crystallization of previously deposited silicate layers under a steam atmosphere. The resultant membranes were able to separate n/isobutane mixtures at relatively high temperatures, displaying separation selectivities of 11.3, 8.9 and 2.5 at 100, 230 and 330 °C, respectively. 相似文献
125.
In a study of the enlargement of pores of coals it has been found that treatment of a bituminous coal (PSOC No. 371, from the Pennsylvania State University Coal Section) with a 5:95 O2:N2 stream 4 h at 400 °C increases the surface area as measured by nitrogen adsorption at 77K by a factor of at least 50 to a value 52 m2 g?1. The increase in pore size was accompanied by a 9.7% weight loss. Simultaneously, the area as measured by carbon dioxide at 195K increased from 61 to 136 m2 g?1 and that measured by carbon dioxide at room temperature increased from 125 to 237 m2 g?1. Attempts to enlarge the pores by oxidation with hydrogen peroxide or ozone were unsuccessful. A Pittsburgh coal subject to a small percentage of oxygen in nitrogen or steam at 300 to 400 °C showed a surface area as measured by nitrogen adsorption of less than 1 m2 g?1 both before and after such pretreatment. This same coal with a 5:95 O2:N2 stream for 4 h at 450 °C showed a surface area of 110 m2 g?1 measured by nitrogen adsorption at 77K. 相似文献
126.
127.
128.
129.
130.