全文获取类型
收费全文 | 2193篇 |
免费 | 2篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 5篇 |
综合类 | 4篇 |
化学工业 | 214篇 |
金属工艺 | 4篇 |
机械仪表 | 103篇 |
建筑科学 | 131篇 |
矿业工程 | 6篇 |
能源动力 | 3篇 |
轻工业 | 631篇 |
水利工程 | 9篇 |
石油天然气 | 21篇 |
武器工业 | 4篇 |
无线电 | 44篇 |
一般工业技术 | 845篇 |
冶金工业 | 7篇 |
原子能技术 | 2篇 |
自动化技术 | 165篇 |
出版年
2015年 | 1篇 |
2012年 | 232篇 |
2011年 | 279篇 |
2010年 | 58篇 |
2009年 | 21篇 |
2008年 | 227篇 |
2007年 | 215篇 |
2006年 | 155篇 |
2005年 | 132篇 |
2004年 | 128篇 |
2003年 | 133篇 |
2002年 | 106篇 |
2001年 | 114篇 |
2000年 | 88篇 |
1999年 | 51篇 |
1998年 | 40篇 |
1997年 | 38篇 |
1996年 | 41篇 |
1995年 | 13篇 |
1994年 | 21篇 |
1993年 | 7篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 14篇 |
1989年 | 11篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 13篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有2198条查询结果,搜索用时 31 毫秒
1.
Cooney CM 《Environmental science & technology》1996,30(11):479A
Government. 相似文献
2.
Cooney CM 《Environmental science & technology》1996,30(9):387A
Society. 相似文献
3.
Cooney CM 《Environmental science & technology》1996,30(8):336A-337A
Government. 相似文献
4.
Cooney CM 《Environmental science & technology》1996,30(5):195A-196A
Government. 相似文献
5.
6.
7.
Shepson PB Kleindienst TE Edney EO Nero CM Cupitt LT Claxton LD 《Environmental science & technology》1986,20(10):1008-1013
8.
9.
Campbell CA Cook FJ Pickett JA Pope TW Wadhams LJ Woodcock CM 《Journal of chemical ecology》2003,29(10):2225-2234
Gynoparous female and male damson-hop aphids, Phorodon humuli (Schrank), were caught in the field by water traps that were releasing the sex pheromone of this species, (1RS,4aR,7S,7aS)-nepetalactol. No behavioral activity was elicited by (4aS,7S,7aR)-nepetalactone, the major sex pheromone component of other aphid species such as Megoura viciae Buckton, even though olfactory cells were found in the secondary rhinaria on the third antennal segment of P. humuli that responded strongly to this compound. Gynoparous female P. humuli in the field responded less strongly to (1R,4aS,7S,7aR)-nepetalactol, the sex pheromone of the bird cherry-oat aphid, Rhopalosiphum padi (L.), than they did to the (4aR,7S,7aS)-nepetalactols, but males responded only to the latter. The (4aR,7S,7aS)-nepetalactone showed no electrophysiological activity so was not used in field trials. Releasing either the (4aS,7S,7aR)-nepetalactone or the (1R,4aS,7S,7aR)-nepetalactol with the (4aR,7S,7aS)-nepetalactols did not inhibit the response of P. humuli gynoparous females and males to the latter. Males of R. padi responded as strongly to the (4aR,7S,7aS)-nepetalactols as they did to (1R,4aS,7S,7aR)-nepetalactol. Males of P. humuli and R. padi responded positively to an increased concentration of the (4aR,7S,7aS)-nepetalactols released from two vials compared with that from a single vial, as did P. humuli (in one of two experiments) and R. padi to the (1RS,4aR,7S,7aS)- and (1R,4aS,7S,7aR)-nepetalactols when released together. 相似文献
10.
The white pine cone beetle, Conophthorus coniperda, exhibited dose and enantiospecific responses to -pinene in stands of mature eastern white pine, Pinus strobus, in a seed orchard near Murphy, North Carolina, USA. (–)--Pinene significantly increased catches of cone beetles to traps baited with (± )-trans-pityol. (+)--Pinene did not increase catches of beetles to pityol-baited traps and interrupted the response of beetles to traps baited with (±)-trans-pityol and (–)--pinene. Maximal attraction of cone beetles to pityol-baited traps was obtained with lures releasing (–)--pinene at a rate of 103 mg/day at 23°C. Lures releasing (–)--pinene at rates lower or higher than 103 mg/day resulted in reduced catches to traps baited with (±)-trans-pityol. The sex ratio in all catches was heavily male biased. Attraction of the clerid predator, Thanasimus dubius, to traps baited with (±)-trans-pityol increased significantly with the presence of -pinene, irrespective of enantiomeric composition. Maximal attraction of T. dubius to pityol-baited traps occurred with devices releasing (–)--pinene at the highest rate tested, 579 mg/d at 23°C, a sub optimal rate for cone beetles. 相似文献