全文获取类型
收费全文 | 3084篇 |
免费 | 4篇 |
专业分类
综合类 | 3篇 |
化学工业 | 15篇 |
金属工艺 | 1篇 |
建筑科学 | 3篇 |
轻工业 | 8篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 5篇 |
一般工业技术 | 7篇 |
冶金工业 | 3024篇 |
原子能技术 | 2篇 |
自动化技术 | 17篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 4篇 |
2012年 | 5篇 |
2011年 | 1篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 91篇 |
1998年 | 894篇 |
1997年 | 498篇 |
1996年 | 316篇 |
1995年 | 170篇 |
1994年 | 151篇 |
1993年 | 172篇 |
1992年 | 27篇 |
1991年 | 35篇 |
1990年 | 38篇 |
1989年 | 45篇 |
1988年 | 53篇 |
1987年 | 54篇 |
1986年 | 35篇 |
1985年 | 34篇 |
1984年 | 1篇 |
1983年 | 11篇 |
1982年 | 14篇 |
1981年 | 20篇 |
1980年 | 40篇 |
1979年 | 8篇 |
1978年 | 13篇 |
1977年 | 94篇 |
1976年 | 216篇 |
1975年 | 6篇 |
1955年 | 1篇 |
排序方式: 共有3088条查询结果,搜索用时 11 毫秒
71.
72.
We report the results of a comprehensive search of Drosophila melanogaster DNA sequences in GenBank for di-, tri-, and tetranucleotide repeats of more than four repeat units, and a DNA library screen for dinucleotide repeats. Dinucleotide repeats are more abundant (66%) than tri- (30%) or tetranucleotide (4%) repeats. We estimate that 1917 dinucleotide repeats with 10 or more repeat units are present in the euchromatic D. melanogaster genome and, on average, they occur once every 60 kb. Relative to many other animals, dinucleotide repeats in D. melanogaster are short. Tri- and tetranucleotide repeats have even fewer repeat units on average than dinucleotide repeats. Our WorldWide Web site (http://www.bio.cornell.edu/genetics/aquadro/+ ++aquadro.html) posts the complete list of 1298 microsatellites (> or = five repeat units) identified from the GenBank search. We also summarize assay conditions for 70 D. melanogaster microsatellites characterized in previous studies and an additional 56 newly characterized markers. 相似文献
73.
JM Koelman HJ Noteborn de Goey LP BJ Verhaar JT Walraven 《Canadian Metallurgical Quarterly》1985,32(11):7195-7198
74.
75.
76.
The ability of morphine to modify sucrose palatability was assessed by the taste reactivity test. In Experiment 1, rats were injected with morphine (0.0, 0.5, 2.0, and 10.0 mg/kg, subcutaneously), 30 min before receiving a 10-min intraoral infusion of 2% or 20% sucrose solution. A dose of 2.0 mg/kg morphine enhanced ingestive reactions elicited by both concentrations of sucrose solution. In Experiment 2, the interval between morphine pretreatment and the taste reactivity test was manipulated. Rats given 2.0 mg/kg morphine 30 or 120 min before testing displayed enhanced ingestive reactions elicited by 20% sucrose solution during the first 5 min of a 10-min test. The results support the hypothesis that morphine enhances the hedonic assessment of sucrose solution. 相似文献
77.
RD Kortschak H Reimann M Zimmer HJ Eyre R Saint DE Jenne 《Canadian Metallurgical Quarterly》1998,51(2):288-292
A 2-year trial was conducted to evaluate the cost-effectiveness of heliotherapy for psoriasis. The course and cost of psoriasis of 46 Finnish patients were first closely monitored for 1 year, then the patients received a 4-week supervised heliotherapy treatment in the Canary Islands, Spain, after which they continued to be followed for another year. Heliotherapy dramatically reduced the severity of psoriasis and also seemed to have favourable long-term effects on psoriasis. The mean direct cost of the 4-week heliotherapy for one patient was FIM12,289 (1 Pound = FIM7.0 in 1989). The cost of flights and half-board in Spain formed nearly 60% (FIM7033) of the total cost. In the year preceding heliotherapy, the mean direct annual cost of antipsoriasis therapy was FIM7335 and in the year after FIM5700, a reduction of 22% in annual costs; this change was not statistically significant because there were large variations in costs among patients. The costs of heliotherapy exceeded manyfold the mean monthly cost of conventional psoriasis therapy. There were no overall savings using heliotherapy in those patients suffering mainly from moderately severe psoriasis. Heliotherapy saved costs only in those patients with severe psoriasis that required expensive medication or ward treatment. Although heliotherapy cannot be regarded as an economical treatment for the average patients with psoriasis, it clears psoriasis effectively and is preferred by patients. Thus, heliotherapy constitutes an alternative for patients suffering severe psoriasis. 相似文献
78.
Asplenia syndrome in conjoined twins: a case report 总被引:1,自引:0,他引:1
Incomplete fission of the primordial cell mass is generally believed to be the cause of conjoined twinning. It may also explain the tendency towards increased symmetry in these twins. We report a case of the rostral duplication type of conjoined twins with an absence of symmetry; one twin had the asplenia syndrome, whereas the other twin was normal. Local environmental factors acting upon the organ anlage may explain the asymmetric development in these conjoined twins. 相似文献
79.
Alter Adam L.; Oppenheimer Daniel M.; Epley Nicholas; Eyre Rebecca N. 《Canadian Metallurgical Quarterly》2007,136(4):569
Humans appear to reason using two processing styles: System 1 processes that are quick, intuitive, and effortless and System 2 processes that are slow, analytical, and deliberate that occasionally correct the output of System 1. Four experiments suggest that System 2 processes are activated by metacognitive experiences of difficulty or disfluency during the process of reasoning. Incidental experiences of difficulty or disfluency--receiving information in a degraded font (Experiments 1 and 4), in difficult-to-read lettering (Experiment 2), or while furrowing one's brow (Experiment 3)--reduced the impact of heuristics and defaults in judgment (Experiments 1 and 3), reduced reliance on peripheral cues in persuasion (Experiment 2), and improved syllogistic reasoning (Experiment 4). Metacognitive experiences of difficulty or disfluency appear to serve as an alarm that activates analytic forms of reasoning that assess and sometimes correct the output of more intuitive forms of reasoning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
80.
HJ 《家用电脑与游戏机》2012,(11):46-47
大家在筛选录像的时候会发现,每一场DOTA2比赛都有自己的等级,分为普通、高、非常高三种。比赛的等级是由每个人的Matchmarkingranking数值所决定的,我们简称其为MMR值,与天梯积分有点像。 相似文献