全文获取类型
收费全文 | 1440055篇 |
免费 | 25682篇 |
国内免费 | 6990篇 |
专业分类
电工技术 | 33915篇 |
综合类 | 6367篇 |
化学工业 | 266709篇 |
金属工艺 | 63097篇 |
机械仪表 | 39714篇 |
建筑科学 | 44361篇 |
矿业工程 | 11257篇 |
能源动力 | 50105篇 |
轻工业 | 102009篇 |
水利工程 | 14464篇 |
石油天然气 | 37272篇 |
武器工业 | 142篇 |
无线电 | 194120篇 |
一般工业技术 | 271340篇 |
冶金工业 | 138970篇 |
原子能技术 | 33671篇 |
自动化技术 | 165214篇 |
出版年
2021年 | 15489篇 |
2020年 | 11748篇 |
2019年 | 14493篇 |
2018年 | 14058篇 |
2017年 | 13265篇 |
2016年 | 20349篇 |
2015年 | 17125篇 |
2014年 | 28493篇 |
2013年 | 87450篇 |
2012年 | 33105篇 |
2011年 | 44169篇 |
2010年 | 40561篇 |
2009年 | 49423篇 |
2008年 | 41743篇 |
2007年 | 38477篇 |
2006年 | 42855篇 |
2005年 | 37072篇 |
2004年 | 39734篇 |
2003年 | 39772篇 |
2002年 | 39071篇 |
2001年 | 35856篇 |
2000年 | 34525篇 |
1999年 | 33296篇 |
1998年 | 37602篇 |
1997年 | 34560篇 |
1996年 | 32475篇 |
1995年 | 28918篇 |
1994年 | 27375篇 |
1993年 | 27279篇 |
1992年 | 25555篇 |
1991年 | 22551篇 |
1990年 | 23022篇 |
1989年 | 22064篇 |
1988年 | 20469篇 |
1987年 | 18847篇 |
1986年 | 18160篇 |
1985年 | 21470篇 |
1984年 | 21931篇 |
1983年 | 19916篇 |
1982年 | 19045篇 |
1981年 | 19120篇 |
1980年 | 17671篇 |
1979年 | 18249篇 |
1978年 | 17522篇 |
1977年 | 16805篇 |
1976年 | 17030篇 |
1975年 | 15793篇 |
1974年 | 15321篇 |
1973年 | 15392篇 |
1972年 | 12866篇 |
排序方式: 共有10000条查询结果,搜索用时 4 毫秒
921.
Albrecht Jason E.; O'Brien Edward J.; Mason Robert A.; Myers Jerome L. 《Canadian Metallurgical Quarterly》1995,21(2):364
An implicit assumption of several causal reasoning models is that readers adopt the goals of a narrative's protagonist during text comprehension. In apparent violation of this assumption, readers participating in Experiment 1 of the present study drew inferences relevant to a protagonist's goal even when that goal was already satisfied from the perspective of the protagonist. In Experiments 2 and 3, participants were explicitly asked to view the text situation from the point of view of the protagonist. In this case, the goals of the reader and the protagonist should be the same. In these experiments, participants focused on the goals of the protagonist only when those goals had not been satisfied from the perspective of the protagonist. These results are discussed in terms of reader- and character-based perspectives and in terms of text characteristics that cue perspective taking. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
922.
923.
M Furuta K Hayakawa S Katano Y Saito Y Nakayama T Takahashi R Imai T Ebara N Mitsuhashi H Niibe 《Canadian Metallurgical Quarterly》1996,26(2):95-98
Vaccination with peptides that induce a specific immune response is a potential prophylactic or therapeutic strategy against viral infections and tumors. Because of the extensive polymorphism of the HLA loci, synthetic peptide vaccines must consist of a cocktail of peptides that bind specifically to different HLA molecules. Such cocktails should be optimized for the target population as each population has its specific HLA gene frequencies. To achieve maximum population coverage with a minimum number of peptides, information is needed on the ranking of the most frequent HLA phenotypes. We introduce the minimal phenotype panel, which is the smallest combination of HLA antigens selected so that the proportion of individuals in a population that express at least one of the antigens in the panel exceeds a desired minimum value. We developed a method for assembling minimal phenotype panels based on known HLA class I gene frequencies. We give an example based on a set of 2446 well-defined HLA-typed, random, healthy, unrelated, Dutch Caucasoid individuals. In addition, we discuss the possibility of assembling minimal phenotype panels based on two-locus haplotypes, which enables the assembly of phenotype panels from the antigens of both loci. 相似文献
924.
本文概述了离子注入过程中污染产生的原因和防止污染的措施,特别强调了对微粒污染和金属污染的防护以满足ULSI加工对离子注入的要求。 相似文献
925.
926.
927.
The paper covers a simple idea. If we sample an aperture, we can obtain valid patterns over a limited angular region about the normal to the aperture. The same expression can be used with near-field measurements. I reduced the expression to a nomograph. A nomograph allows one to rapidly test various choices. In the second half of the paper, I answer questions caused by the February column which discussed polarization (Milligan, IEEE Antennas. Propag. Mag., vol.38, no.1, p.56-8, 1996) 相似文献
928.
The formation of mullite was investigated using microcomposite powders which consist of α-alumina cores and amorphous silica coatings. Differential thermal analysis and X-ray diffraction showed that the mullitization reaction was endothermic. In contrast, mullite forms exothermically in samples prepared by sol-gel processing. The results are shown to be consistent with available thermodynamic data for mullite formation from different alumina and silica phases. 相似文献
929.
930.