全文获取类型
收费全文 | 2403篇 |
免费 | 8篇 |
专业分类
电工技术 | 46篇 |
化学工业 | 47篇 |
金属工艺 | 11篇 |
机械仪表 | 11篇 |
建筑科学 | 11篇 |
能源动力 | 5篇 |
轻工业 | 26篇 |
水利工程 | 1篇 |
无线电 | 74篇 |
一般工业技术 | 62篇 |
冶金工业 | 1925篇 |
原子能技术 | 10篇 |
自动化技术 | 182篇 |
出版年
2022年 | 4篇 |
2020年 | 4篇 |
2017年 | 9篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 33篇 |
2012年 | 9篇 |
2011年 | 19篇 |
2010年 | 13篇 |
2009年 | 13篇 |
2008年 | 15篇 |
2007年 | 16篇 |
2006年 | 17篇 |
2005年 | 17篇 |
2004年 | 13篇 |
2003年 | 11篇 |
2002年 | 13篇 |
2001年 | 7篇 |
2000年 | 19篇 |
1999年 | 59篇 |
1998年 | 543篇 |
1997年 | 336篇 |
1996年 | 221篇 |
1995年 | 138篇 |
1994年 | 101篇 |
1993年 | 140篇 |
1992年 | 26篇 |
1991年 | 31篇 |
1990年 | 25篇 |
1989年 | 41篇 |
1988年 | 44篇 |
1987年 | 52篇 |
1986年 | 45篇 |
1985年 | 37篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 18篇 |
1981年 | 20篇 |
1980年 | 24篇 |
1979年 | 8篇 |
1978年 | 14篇 |
1977年 | 51篇 |
1976年 | 107篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 9篇 |
1972年 | 5篇 |
1971年 | 5篇 |
1969年 | 5篇 |
排序方式: 共有2411条查询结果,搜索用时 0 毫秒
21.
22.
23.
Because knowledge has advanced in several fields related to the treatment of early breast cancer, revising the landmark 1992 standards for breast-conservation treatment by these four organizations is appropriate. The current report reviews and summarizes the literature and describes the selection and evaluation of patients, the technical aspects of surgical treatment and irradiation, follow-up care, and areas for further research. 相似文献
24.
This paper considers the fixed-structure, discrete-time mixed H 2 / H X controller synthesis problem in the delta operator (difference operator) framework. The differential operator and shift operator versions of the problem are reviewed for comparison, and necessary conditions are derived for all three formulations. A quasi-Newton/continuation algorithm is then used to obtain approximate solutions to these equations. Controllers are synthesized for two numerical examples, and the performance of the algorithm on the differential, difference and shift operator versions of the problems is compared. 相似文献
25.
26.
A group of rhesus monkeys, consisting of 8 matrilines of up to 4 generations each and 9 unrelated adult males, was studied for 2 yrs. Group size varied between 75 and 91 individuals. Data collection consisted of ad lib recording of agonistic interactions. Results indicate that adult male interference in agonistic episodes was strongly biased against adolescent and adult male participants, whereas adult female interference was biased in favor of kin and in support of younger animals against older animals. Although natal males also were biased in favor of their kin, their selective targeting of sexually mature males was independent of kinship. Adolescent males targeted adult males, but only in defense of kin. It is suggested that this selective interference against adolescent and adult males by adult males has the potential to profoundly modify male agonistic participation in intragroup encounters after puberty. Because female support is influenced primarily by kinship, females less consistently interfere against male agonistic participants. Adult males may therefore play an important role in the socialization of male agonistic expression. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
27.
28.
29.
30.
Herbert J. Bernstein 《Quantum Information Processing》2006,5(6):451-461
Recent advances in experimental technique make SuperDense Teleportation (SDT) possible only now, ten years after my first proposal at an ISI Torino summer conference on Quantum Computing. The effect uses remote state preparation to send more state-specifying parameters per bit than ordinary quantum teleportation (QT) can transmit. The SDT uses a maximally entangled state to teleport the relative phases of an n-dimensional state with equal amplitudes on every standard basis vector. For n greater than or equal to 3, the SDT sends more of these state-specifying parameters than QT. In the limit of large n the ratio is 2 to 1, hence the nomenclature by analogy with Super Dense Coding. Alice’s measurements and Bob’s transformations are far simpler than their corresponding operations in QT. The roles of Charles who chooses the state and Diana who deploys it are different than in QT. My discussion includes a brief review of the progress and possibilities of realization for several different experimental approaches around the world. This paper is the write-up of my remarks at the Festschrift conference for Anton Zeilinger, for many years a close collaborator in the Hampshire College NSF grant continuing our work with Mike Horne and Danny Greenberger started under Cliff Shull at MIT in the late 20th century. 相似文献