全文获取类型
收费全文 | 3310篇 |
免费 | 119篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 41篇 |
综合类 | 21篇 |
化学工业 | 575篇 |
金属工艺 | 61篇 |
机械仪表 | 54篇 |
建筑科学 | 141篇 |
矿业工程 | 12篇 |
能源动力 | 117篇 |
轻工业 | 410篇 |
水利工程 | 21篇 |
石油天然气 | 20篇 |
无线电 | 265篇 |
一般工业技术 | 400篇 |
冶金工业 | 819篇 |
原子能技术 | 24篇 |
自动化技术 | 461篇 |
出版年
2023年 | 28篇 |
2022年 | 58篇 |
2021年 | 70篇 |
2020年 | 48篇 |
2019年 | 41篇 |
2018年 | 63篇 |
2017年 | 50篇 |
2016年 | 63篇 |
2015年 | 61篇 |
2014年 | 101篇 |
2013年 | 157篇 |
2012年 | 117篇 |
2011年 | 153篇 |
2010年 | 117篇 |
2009年 | 102篇 |
2008年 | 120篇 |
2007年 | 135篇 |
2006年 | 114篇 |
2005年 | 82篇 |
2004年 | 77篇 |
2003年 | 86篇 |
2002年 | 70篇 |
2001年 | 65篇 |
2000年 | 64篇 |
1999年 | 66篇 |
1998年 | 268篇 |
1997年 | 163篇 |
1996年 | 108篇 |
1995年 | 69篇 |
1994年 | 82篇 |
1993年 | 81篇 |
1992年 | 38篇 |
1991年 | 37篇 |
1990年 | 32篇 |
1989年 | 36篇 |
1988年 | 29篇 |
1987年 | 31篇 |
1986年 | 18篇 |
1985年 | 25篇 |
1984年 | 20篇 |
1983年 | 22篇 |
1981年 | 17篇 |
1980年 | 22篇 |
1979年 | 13篇 |
1978年 | 15篇 |
1977年 | 29篇 |
1976年 | 47篇 |
1974年 | 14篇 |
1973年 | 18篇 |
1972年 | 13篇 |
排序方式: 共有3442条查询结果,搜索用时 15 毫秒
991.
992.
993.
Kragh-S?rensen CE Hansen PC Baastrup EF Hvidberg 《Canadian Metallurgical Quarterly》1976,9(4):178-182
Based on the evidence that therapeutic plasma concentration range in fact exists for the tricyclic antidepressant drug, Nortriptyline (range 50-150 ng/ml), three different investigations were under taken in order to clarify some clinical pharmacological problems during long-term treatment with this drug. The possible prophlactic effect of the drug in recurrent affective disorders was specially examined in a group of patients with a high risk of episodes in their unipolar manic-depressive disease. The results highly demonstrate the value of monitoring plasma levels in achieving therapeutic control. Depressive relapses during treatment, for months and years, were only related to therapeutic insufficient plasma levels of the drug. 相似文献
994.
P. V. Hansen F. L. Kauffman L. H. Wiedermann 《Journal of the American Oil Chemists' Society》1959,36(5):193-195
Summary A direct spectrophotometric method for the determination of butylated hydroxyanisole has been presented. This procedure allows
good precision in the analysis of lard and hardened lard containing from 0 to 100 p.p.m. of BHA and is more reliable than
existing colorimetric techniques, especially in the lower range of antioxidant concentrations. 相似文献
995.
996.
997.
This paper is an overview of the Trio system which enables users to simultaneously develop and execute programs at three terminals. The system consists of an operating system written in Concurrent Pascal and a set of standard programs written in Sequential Pascal. The system has been used on a PDP 11/55 minicomputer since spring 1979. This work concludes 5 years of experience with the first abstract language for concurrent programming. 相似文献
998.
An effective surface treatment for adhesive bonding of polyethylene has been developed. It involves exposing the polymer to an environment of elemental fluorine or fluorine diluted in argon. By this treatment, extensive fluorination of the surface region is effected. The fluorinated surface permits formation of strong adhesive joints by conventional adhesive bonding techniques even though the wettability of the new surface is similar to polytetrafluoroethylene. We believe that treatment of the polymer with elemental fluorine effectively eliminates the weak boundary layer associated with polyethylene by either crosslinking or by increasing the molecular weight in the surface region. 相似文献
999.
1000.
Lysozyme activity in cerebrospinal fluid. Studies in inflammatory and non-inflammatory CNS disorders
Lysozyme activity was measured in cerebrospinal fluid (CSF) from 114 patients with inflammatory (bacterial and serous meningitis, polyradiculitis, encephalitis) and non-inflammatory (multiple sclerosis, CNS tumors, cerebral vascular diseases) CNS diseases. Highly elevated values were found consistently in patients with bacterial meningitis. Elevated values were found also in patients with encephalitis, polyradiculitis, multiple sclerosis and CNS tumors, but a considerable overlapping between these groups and normal controls precludes the use of CSF lysozyme measurements as a diagnostic aid in the latter disease groups. Simultaneous measurements of lysozyme, albumin and IgG in CSF and serum suggested that the mechanism for increased CSF lysozyme values in bacterial meningitis is mainly a breakdown of the blood/brain barrier, whereas the increased CSF lysozyme values in the remaining groups of patients are more likely caused by production of lysozyme by cells within the meninges (neutrophilic granulocytes, monocytes?). 相似文献