全文获取类型
收费全文 | 151702篇 |
免费 | 2044篇 |
国内免费 | 655篇 |
专业分类
电工技术 | 3115篇 |
综合类 | 187篇 |
化学工业 | 24072篇 |
金属工艺 | 5781篇 |
机械仪表 | 4942篇 |
建筑科学 | 4418篇 |
矿业工程 | 377篇 |
能源动力 | 3927篇 |
轻工业 | 17306篇 |
水利工程 | 1140篇 |
石油天然气 | 618篇 |
武器工业 | 5篇 |
无线电 | 20493篇 |
一般工业技术 | 28843篇 |
冶金工业 | 23754篇 |
原子能技术 | 2341篇 |
自动化技术 | 13082篇 |
出版年
2019年 | 834篇 |
2018年 | 1081篇 |
2017年 | 1131篇 |
2016年 | 1268篇 |
2015年 | 1063篇 |
2014年 | 1796篇 |
2013年 | 6575篇 |
2012年 | 3192篇 |
2011年 | 4608篇 |
2010年 | 3594篇 |
2009年 | 4151篇 |
2008年 | 4647篇 |
2007年 | 4913篇 |
2006年 | 4350篇 |
2005年 | 4108篇 |
2004年 | 4002篇 |
2003年 | 3899篇 |
2002年 | 3928篇 |
2001年 | 3980篇 |
2000年 | 3742篇 |
1999年 | 3691篇 |
1998年 | 6632篇 |
1997年 | 5227篇 |
1996年 | 4460篇 |
1995年 | 3709篇 |
1994年 | 3358篇 |
1993年 | 3184篇 |
1992年 | 2783篇 |
1991年 | 2690篇 |
1990年 | 2628篇 |
1989年 | 2614篇 |
1988年 | 2459篇 |
1987年 | 2166篇 |
1986年 | 2115篇 |
1985年 | 2556篇 |
1984年 | 2316篇 |
1983年 | 2195篇 |
1982年 | 2068篇 |
1981年 | 1991篇 |
1980年 | 1860篇 |
1979年 | 1874篇 |
1978年 | 1770篇 |
1977年 | 2085篇 |
1976年 | 2562篇 |
1975年 | 1583篇 |
1974年 | 1430篇 |
1973年 | 1453篇 |
1972年 | 1196篇 |
1971年 | 1115篇 |
1970年 | 948篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Xiaoling He Hodgson J.W. 《Intelligent Transportation Systems, IEEE Transactions on》2002,3(4):244-251
For pt.I see ibid., vol.3, no.4, p.235-43 (2002). Hybrid electric vehicle (HEV) simulation is conducted based on the model developed for a parallel HEV built in the University of Tennessee, Knoxville (UT-HEV). The HEV simulation is a parametric analysis of the power control schemes and vehicle performance. Major parameters are evaluated for the vehicle driven under the standard urban and highway driving schedules. The results indicate that current configuration of the UT-HEV NEON has superb capability for battery state of charge (SOC) recovery while meeting the velocity request of the given driving schedules. Recommendations are given from the simulation for optimal performance in light of the HEV power control, capability for SOC recovery through regeneration and regenerative braking, as well as velocity, acceleration and range performance. 相似文献
992.
A method of determination for solasodine glycosides by using thin-layer chromatography (TLC) immunostaining was investigated. Solasodine glycosides separated by silica gel TLC were transferred to a polyvinylidene difluoride membrane. The membrane was treated with sodium periodate solution followed by bovine serum albumin (BSA), resulting in a solasodine glycoside-BSA conjugate. Conjugation was confirmed by matrix-assisted laser desorption/ionization mass spectrometry. Individual spots were stained by monoclonal antibody against solamargine. Immunostaining of solasodine glycosides was more sensitive compared to other stainings. The newly established immunostaining method can be extended to analysis of the distribution of solasodine glycoside in the plant body. 相似文献
993.
Park Y.C. Lee K.Y. Youn D.H. Kim N.H. Kim W.K. Park S.H. 《IEEE transactions on bio-medical engineering》1992,39(8):868-871
An efficient algorithm detecting the presence of a fetal QRS complex is presented. The proposed fetal QRS detection method computes the averaged magnitude of the difference between the fetal ECG signal and the reference signal to detect the fetal QRS event. The detected fetal QRS complexes are exponentially averaged to generate the template signal which can track the slowly varying shape of the fetal ECG signal. As an effort to obtain improved detection performances, two approaches of normalizing the fetal ECG signal and the template are considered. 相似文献
994.
The authors demonstrate the application of a commercially available SiGe heterojunction bipolar transistor monolithic microwave integrated circuit technology to active mixers in future communication systems at 5.7 GHz and above. This technology can be used to realise circuits with less than 50 mW power consumption, conversion gains above 15 dB and small double sideband noise figures of 3.6 and 9.4 dB for 5.7 and 11.2 GHz Gilbert cell mixer circuits, respectively 相似文献
995.
Modeling of stress and electromigration at the microscopic level, in confined interconnect metallic lines with tungsten studs, can very well account for the resistance behaviour in time. The resistance change at saturation for a metallic line with blocking boundaries at both ends can be related, according to the model, to threshold product (jL)c found by Blech [1]. 相似文献
996.
997.
Predicts the future of behavior therapy, focusing on theoretical development, therapeutic techniques, and empirical research. The importance of cognitive and affective processes in behavior change will attract increasing attention. Already one of the most widely adopted approaches, behavior therapy will be used to treat an expanded range of psychiatric disorders and health problems. Research will focus on comparative outcome studies and provide probes for investigating the nature of specific disorders and the mechanisms of therapeutic change. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
998.
Tested whether the global shape of objects can be processed without accessing semantic or identity information. Ss judged which of 2 fragmented forms had the same global shape as a reference stimulus. Matching stimuli could be physically identical, semantically related, or unrelated. The reference stimulus and nonmatching (distractor) form could be semantically related or unrelated. Similarity effects in the related condition were unconfounded with matches nameable and nonnameable forms. For nameable forms, related matching forms facilitated performance; a related distractor disrupted performance. Semantic interference was eliminated when nameable distractors were replaced with nonnameable partners; semantic similarity effects on matching were eliminated with a nonnameable reference stimulus and with inverted targets and distractors. Access to information concerning global shape does not normally occur without object identification. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
999.
1000.