全文获取类型
收费全文 | 260583篇 |
免费 | 4448篇 |
国内免费 | 1818篇 |
专业分类
电工技术 | 5412篇 |
技术理论 | 5篇 |
综合类 | 1165篇 |
化学工业 | 42037篇 |
金属工艺 | 11020篇 |
机械仪表 | 7741篇 |
建筑科学 | 6591篇 |
矿业工程 | 1660篇 |
能源动力 | 5591篇 |
轻工业 | 25799篇 |
水利工程 | 2890篇 |
石油天然气 | 5999篇 |
武器工业 | 243篇 |
无线电 | 27783篇 |
一般工业技术 | 49182篇 |
冶金工业 | 47208篇 |
原子能技术 | 5616篇 |
自动化技术 | 20907篇 |
出版年
2021年 | 2476篇 |
2019年 | 2121篇 |
2018年 | 3385篇 |
2017年 | 3357篇 |
2016年 | 3684篇 |
2015年 | 2797篇 |
2014年 | 4578篇 |
2013年 | 11353篇 |
2012年 | 7686篇 |
2011年 | 10191篇 |
2010年 | 8114篇 |
2009年 | 8667篇 |
2008年 | 9472篇 |
2007年 | 9585篇 |
2006年 | 8431篇 |
2005年 | 7386篇 |
2004年 | 6654篇 |
2003年 | 6200篇 |
2002年 | 6209篇 |
2001年 | 6318篇 |
2000年 | 5906篇 |
1999年 | 5875篇 |
1998年 | 12854篇 |
1997年 | 9533篇 |
1996年 | 7275篇 |
1995年 | 5525篇 |
1994年 | 5081篇 |
1993年 | 4947篇 |
1992年 | 3943篇 |
1991年 | 3751篇 |
1990年 | 3823篇 |
1989年 | 3770篇 |
1988年 | 3530篇 |
1987年 | 3019篇 |
1986年 | 3050篇 |
1985年 | 3408篇 |
1984年 | 3321篇 |
1983年 | 3074篇 |
1982年 | 2698篇 |
1981年 | 2902篇 |
1980年 | 2643篇 |
1979年 | 2839篇 |
1978年 | 2736篇 |
1977年 | 2841篇 |
1976年 | 3693篇 |
1975年 | 2457篇 |
1974年 | 2290篇 |
1973年 | 2320篇 |
1972年 | 1981篇 |
1971年 | 1785篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
131.
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
132.
133.
K Alanko L Kanerva B Mohell-Talolahti R Jolanki T Estlander 《Canadian Metallurgical Quarterly》1996,35(4):647-648
The biotransformation of oxazepam by Bifidobacterium bifidum was studied. The major metabolite was purified by chromatographic methods and found to be desmethyldiazepam using NMR, IR and other physicochemical data. 相似文献
134.
135.
136.
Translated from Izmeritel'naya Tekhnika, No. 3, pp. 57–58, March, 1993. 相似文献
137.
Lewis Gloria J.; Greenburg Sharon L.; Hatch David B. 《Canadian Metallurgical Quarterly》1988,19(1):81
We report the results of the first national survey of psychologists in private practice regarding their participation in peer consultation groups. The sample (71% return) was drawn from 800 randomly selected psychologists listed in the National Register of Health Service Providers in Psychology. We found that 23% of the sample currently belonged to peer consultation groups, and 24% had belonged in the past. Of those not currently in groups, 61% expressed the desire to belong if one were available. There were virtually no significant demographic differences between current members and nonmembers. We examined the following group characteristics: formation, length of existence, size, membership, leadership, theoretical orientation, range of experience, time and place, content, and group process. Groups tended to be small, informal, and leaderless; however, we found great variation among groups on all dimensions. Findings also showed a high degree of satisfaction with membership. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
138.
139.
140.
1. A total of 360 Japanese quail of 4 commercial meat-type lines and two diet treatments (260 and 216 g/kg or 238 and 195 g/kg of crude protein (CP) in the starter and grower diet, respectively) were used. 2. The positive effect of a high CP diet on body weight was significant only for the first 4 weeks after hatching. 3. The mean age at inflection point of the growth curve (t+) across lines and sexes was 1.4 d (0.6 to 2.8 d within line/sex groups) earlier for quail fed on a high CP diet than in quail receiving a low CP diet. The inflection (y+) and asymptotic (A) weights were similar under both dietary protein concentrations. Nevertheless, the shape of the growth curve, characterised by the ratio y+/A and parameter of the maturing rate k, was significantly influenced by diet. 4. A higher food intake and less efficient food conversion were found for quail fed on a high CP diet in the period from 15 to 28 d of age. 5. The fattening traits such as body weight, cumulative food intake and food conversion, were not affected by dietary CP content at the age of 5 weeks. 6. The effects of line on body weight, food intake and food conversion are discussed. 相似文献