全文获取类型
收费全文 | 5640篇 |
免费 | 96篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 44篇 |
综合类 | 1篇 |
化学工业 | 720篇 |
金属工艺 | 58篇 |
机械仪表 | 59篇 |
建筑科学 | 49篇 |
矿业工程 | 4篇 |
能源动力 | 91篇 |
轻工业 | 206篇 |
水利工程 | 12篇 |
石油天然气 | 7篇 |
无线电 | 305篇 |
一般工业技术 | 525篇 |
冶金工业 | 3341篇 |
原子能技术 | 27篇 |
自动化技术 | 296篇 |
出版年
2023年 | 26篇 |
2022年 | 60篇 |
2021年 | 75篇 |
2020年 | 73篇 |
2019年 | 65篇 |
2018年 | 86篇 |
2017年 | 62篇 |
2016年 | 63篇 |
2015年 | 58篇 |
2014年 | 79篇 |
2013年 | 177篇 |
2012年 | 105篇 |
2011年 | 107篇 |
2010年 | 76篇 |
2009年 | 87篇 |
2008年 | 86篇 |
2007年 | 74篇 |
2006年 | 83篇 |
2005年 | 59篇 |
2004年 | 43篇 |
2003年 | 47篇 |
2002年 | 45篇 |
2001年 | 22篇 |
2000年 | 44篇 |
1999年 | 148篇 |
1998年 | 1110篇 |
1997年 | 622篇 |
1996年 | 430篇 |
1995年 | 243篇 |
1994年 | 202篇 |
1993年 | 203篇 |
1992年 | 55篇 |
1991年 | 74篇 |
1990年 | 54篇 |
1989年 | 75篇 |
1988年 | 66篇 |
1987年 | 74篇 |
1986年 | 62篇 |
1985年 | 42篇 |
1984年 | 21篇 |
1983年 | 21篇 |
1982年 | 40篇 |
1981年 | 47篇 |
1980年 | 46篇 |
1979年 | 22篇 |
1978年 | 19篇 |
1977年 | 85篇 |
1976年 | 174篇 |
1975年 | 16篇 |
1973年 | 24篇 |
排序方式: 共有5745条查询结果,搜索用时 15 毫秒
1.
2.
Patel Sapna Kumar Dushyant Chaurasiya Nitesh Kumar Tripathi Shweta 《Semiconductors》2019,53(13):1797-1803
Semiconductors - In the present paper, analytical modeling of surface potential and drain current for hetero-dielectric double gate tunnel FET (HDG-TFET) has been done. The two dimensional (2D)... 相似文献
3.
Journal of Mechanical Science and Technology - An experimental study is performed to explore the effect of swirl and number of swirler vanes on combustion characteristics of methane inverse... 相似文献
4.
Parsania P. H. Sankhavara Dharmesh B. Chopda Jalpa Patel Jignesh P. 《Polymer Bulletin》2020,77(6):3111-3128
Polymer Bulletin - Jute and glass composites of epoxy resin of (2E, 6E)-bis(4-hydroxybenzylidene)cyclohexanone (EBHBC) were prepared by compressing molding technique using three different hardeners... 相似文献
5.
全流程低功耗设计技术的应用 总被引:1,自引:0,他引:1
SameerPatel 《电子设计应用》2004,(1):91-92
随着便携式电子设备的日益使用,要求集成电路IC及SoC的功耗越来越低。在今后日益复杂的设计中,实现一个可靠的电源网络以减小功耗变成了主要的挑战。对于使用者来说,期待每一代新产品都具有新型功能,同时也希望产品的体积小并具有较长的工作时间。解决这个难题的方法之一就是采用新型的IC设计技术,以提供小而且高效的晶体管。在整个设计流程中,为了使器件的性能和可靠性最优,电源方面的限制非常关键。例如在逻辑门应用中,由于开关从一种状态转换到另一种状态从而引起动态功耗。在开关的转换过程中,和晶体管门极相连的所有内部电容将会被… 相似文献
6.
S Moss B Ibbotson H Prosser D Goldberg P Patel N Simpson 《Canadian Metallurgical Quarterly》1997,32(6):344-354
The Psychiatric Assessment Schedule for Adults with Developmental Disability (PAS-ADD) is a semi-structured interview for use with respondents who have learning disability and for key informants. This report investigates the ability of the instrument to detect symptoms that had been found to exist during routine clinical assessment of the patients. Field trials involved 95 referred patients with learning disability and a key informant for each sample member. Clinical opinions of the referring psychiatrists were sought using a symptom checklist. Referrer checklist symptoms and PAS-ADD data were both factor analysed. Validity testing involved (a) computation of correlations between PAS-ADD factors and checklist data and (b) comparison of PAS-ADD and referrers' diagnoses. Results indicated good validity for the PAS-ADD in relation to psychotic symptoms and depressive symptoms. Anxiety symptom identification was not well validated, probably due to small numbers. Expansive mood identified by the referrers was not detected by the PAS-ADD because there is currently no corresponding section in the interview. Where the PAS-ADD produced a diagnosis (in 58 members of the sample), 44 were in agreement with the referrer. Probability of diagnosis by PAS-ADD increased with the number of relevant active symptoms identified by the referrer. The PAS-ADD has been shown in a previous report to have the sensitivity to detect mental disorders not known to psychiatric services. For psychotic and depressive conditions, our results showed that symptom detection was in good agreement with the information provided by the referring psychiatrists on their patients. The PAS-ADD needs a section on hypomania and further investigation of its detection of anxiety disorders. 相似文献
7.
FJ Overdyk PM Gramling-Babb JR Handy NI Faller MJ Miller 《Canadian Metallurgical Quarterly》1997,84(1):213-215
Robertsonian translocations, although relatively common as a constitutional genetic aberration, are rarely encountered in leukaemia. We report a case of acute myeloid leukaemia which showed an acquired Robertsonian translocation in the form of der(14;21) by cytogenetic analysis of leukaemic cells. This was confirmed by the PHA-stimulated culture of peripheral blood lymphocytes. A review of the literature identifies only eight reported cases of acquired Robertsonian translocations in leukaemia. In the majority of cases the Robertsonian translocation occurs as a secondary change in a complex abnormal clone, whereas in two out of nine patients reported, including ours, it is found as a sole karyotypic abnormality. 相似文献
8.
Twenty-six patients with an intracardiac myxoma underwent surgical resection at our institution from 1977 through 1992. Left atrial myxoma was diagnosed in 22 patients, left ventricular in 1, right atrial in 2, and right ventricular in 1. Six patients were asymptomatic; preoperative symptoms included dyspnea, arrhythmias, embolic episodes, and syncope. The diagnosis was established with transthoracic echocardiography in all cases but one. Surgery was performed in all cases with the aid of cardiopulmonary bypass with moderate hypothermia and cold crystalloid cardioplegia. One patient with a left ventricular myxoma died in a comatose state during the immediate postoperative period. Long-term clinical and echocardiographic evaluation was performed in 19 patients; results were excellent (all the patients were in New York Heart Association functional class I or II), and no recurrences were documented. The clinical characteristics, diagnostic methods, and surgical approach are presented and discussed. 相似文献
9.
10.