全文获取类型
收费全文 | 427篇 |
免费 | 28篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 65篇 |
金属工艺 | 14篇 |
机械仪表 | 15篇 |
建筑科学 | 5篇 |
能源动力 | 3篇 |
轻工业 | 16篇 |
水利工程 | 2篇 |
无线电 | 27篇 |
一般工业技术 | 93篇 |
冶金工业 | 156篇 |
原子能技术 | 11篇 |
自动化技术 | 43篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 11篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 11篇 |
2016年 | 9篇 |
2015年 | 9篇 |
2014年 | 9篇 |
2013年 | 16篇 |
2012年 | 24篇 |
2011年 | 17篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 11篇 |
2007年 | 15篇 |
2006年 | 10篇 |
2005年 | 5篇 |
2004年 | 11篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 12篇 |
1998年 | 40篇 |
1997年 | 18篇 |
1996年 | 20篇 |
1995年 | 13篇 |
1994年 | 12篇 |
1993年 | 8篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 18篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1974年 | 2篇 |
1972年 | 5篇 |
1971年 | 2篇 |
排序方式: 共有455条查询结果,搜索用时 0 毫秒
151.
152.
153.
154.
Dawson Geraldine; Toth Karen; Abbott Robert; Osterling Julie; Munson Jeff; Estes Annette; Liaw Jane 《Canadian Metallurgical Quarterly》2004,40(2):271
This study investigated social attention impairments in autism (social orienting, joint attention, and attention to another's distress) and their relations to language ability. Three- to four-year-old children with autism spectrum disorder (ASD; n = 72), 3- to 4-year-old developmentally delayed children (n = 34), and 12- to 46-month-old typically developing children (n = 39), matched on mental age, were compared on measures of social orienting, joint attention, and attention to another's distress. Children with autism performed significantly worse than the comparison groups in all of these domains. Combined impairments in joint attention and social orienting were found to best distinguish young children with ASD from those without ASD. Structural equation modeling indicated that joint attention was the best predictor of concurrent language ability. Social orienting and attention to distress were indirectly related to language through their relations with joint attention. These results help to clarify the nature of social attention impairments in autism, offer clues to developmental mechanisms, and suggest targets for early intervention. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
155.
156.
A comparative assessment is performed on one of the false morel mushrooms, Gyromitra esculenta, including the amounts of some hydrazines present in this fungus, the cancer-inducing doses of these chemicals or the mushroom used in animal experiments, the total amounts of the hydrazines or mushroom needed to induce neoplasms in mice and the estimated total amounts of hydrazines or mushroom needed to induce cancer in humans. When one compares the estimated amounts of hydrazines required to induce cancer with the amount of raw Gyromitra esculenta needed to yield a similar effect, it becomes clear that to date 37 percent of the carcinogenic ingredients of this fungus have been identified. 相似文献
157.
158.
AE Tollefson TW Hermiston DL Lichtenstein CF Colle RA Tripp T Dimitrov K Toth CE Wells PC Doherty WS Wold 《Canadian Metallurgical Quarterly》1998,392(6677):726-730
DNA viruses have evolved elaborate mechanisms to overcome host antiviral defences. In adenovirus-infected cells, programmed cell death (apoptosis) induced by the cytokine tumour necrosis factor (TNF) is inhibited by several adenovirus-encoded proteins. Occupation of the cell-surface receptor Fas, a member of the TNF-receptor superfamily that is expressed on most cell types, triggers apoptosis of that cell. Here we show that the adenovirus RID (for receptor internalization and degradation) protein complex, which is an inhibitor of TNF-induced apoptosis, mediates internalization of cell-surface Fas and its destruction inside lysosomes within the cell. Fas has not previously been shown to be internalized and then degraded. RID also mediates internalization of the receptor for epidermal growth factor, but it does not affect the transferrin receptor or class I antigens of the major histocompatibility complex. Removal of Fas from the surface of adenovirus-infected cells expressing RID may allow infected cells to resist Fas-mediated cell death and thus promote their survival. 相似文献
159.
B Toth 《Canadian Metallurgical Quarterly》1980,97(2):97-108
Twenty actual new cancer-causing hydrazines, hydrazides, and hydrazones of synthetic or natural origin are described. These compounds induce tumors in various target tissues in mice, hamsters and rats. To nine of these compounds the human population is exposed in the form of drugs, agricultural herbicides, and naturally occurring ingredients of edible mushrooms. Yet, with one exception, none of the hydrazines described here were investigated for cancer-inducing abilities in man. The human population should be warned against the use of this hazardous class of chemicals, the total number of which is now 40. 相似文献
160.