全文获取类型
收费全文 | 115篇 |
免费 | 4篇 |
专业分类
林业 | 7篇 |
农学 | 6篇 |
15篇 | |
综合类 | 4篇 |
农作物 | 6篇 |
水产渔业 | 12篇 |
畜牧兽医 | 49篇 |
园艺 | 7篇 |
植物保护 | 13篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 8篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1963年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有119条查询结果,搜索用时 15 毫秒
61.
Conservation: limits of land sparing 总被引:1,自引:0,他引:1
Fischer J Batáry P Bawa KS Brussaard L Chappell MJ Clough Y Daily GC Dorrough J Hartel T Jackson LE Klein AM Kremen C Kuemmerle T Lindenmayer DB Mooney HA Perfecto I Philpott SM Tscharntke T Vandermeer J Wanger TC Von Wehrden H 《Science (New York, N.Y.)》2011,334(6056):593; author reply 594-593; author reply 595
62.
63.
64.
65.
66.
67.
Daniel Kurjak Katarína St?elcová ?ubica Ditmarová Tibor Priwitzer Jaroslav Kmet’ Marián Homolák Viliam Pichler 《European Journal of Forest Research》2012,131(6):1737-1746
Physiological reactions of 25-year-old Norway spruce (Picea abies (L.) Karst.) trees to drought were examined during 2009 vegetation period. During the second half of summer, the decrease in soil water content was observed and irrigation was applied to a group of spruce trees, while the second group was treated under natural soil drought. The response to water deficit was recorded at the level of leaf water potential (ΨL). However, it appears that ΨL plays minor role in early stomata regulation of Norway spruce as CO2 assimilation rate (P N) and stomatal conductance (g S) were reduced already before water potential decrease. Leaf water potential decreased significantly only in case when soil water content was low in the long run and when transpiration losses were simultaneously relatively high. Almost complete stomatal closure even of the irrigated trees was caused by the increase in the vapour pressure deficit of the air (D) above the value of approximately 1.5?kPa. Low values of D were accompanied by partial stomata opening of drought-treated trees. In non-irrigated spruce trees, the values of P N decreased by 35–55% in comparison with irrigated trees. No drought-induced significant changes were found either in chlorophyll and carotenoid concentration (chl a?+?b, car) or in maximal photochemical efficiency of photosystem II (F v/F m). High rates of sap flow (F) did not always lead to stomatal closure during midday. It?appears that high transpiration rates do not control stomatal response to D. 相似文献
68.
In the present series of cases, 8 laparoscopic cryptorchidectomies and 4 laparoscopic ovariectomies were carried out in sedated standing horses. Sedation involved a lesser anaesthesiological risk than does general anaesthesia. As compared to laparotomic exposure, the minimally invasive laparoscopic intervention provided better visualisation, shorter operative time and faster recovery. The blood vessels supplying the testes and ovaries and the suspensory ligaments of the organs were sealed and cut with EnSeal?, an adaptive bipolar electrosurgical blood vessel- and tissue-sealing device. The clinical use of the blood vessel- and tissue-sealing device proved to be successful in all cases. Gradual separation of the intact tissue from the treated, compacted, dehydrated and homogenised tissue areas and occlusion of the lumen of blood vessels treated with the device could be observed in all histological sections. To the best of our knowledge, this is the first report on the use of EnSeal? for laparoscopic cryptorchidectomy and ovariectomy in horses. 相似文献
69.
70.
Li C La MP Sun P Kurtan T Mandi A Tang H Liu BS Yi YH Li L Zhang W 《Marine drugs》2011,9(8):1403-1418
Six new (3Z,5E)-11,20-epoxybriara-3,5-dien-7,18-olide diterpenoids, gemmacolides N-S (1-6), were isolated together with four known analogues, juncenolide D, and juncins R, S and U (7-10), from the South China Sea gorgonian Dichotella gemmacea. The structures of the new compounds were elucidated by the detailed analysis of spectroscopic data in combination with the comparison with reported data. The absolute configuration of 1 was determined by a TDDFT calculation of its solution ECD spectrum, affording the determination of absolute configuration of other analogues by simply comparing their ECD spectra with that of 1. The cytotoxic and antimicrobial activities of these compounds were evaluated. In preliminary in vitro bioassays, compounds 4, 5, 6, 8 and 9 showed cytotoxicity against A549 and MG63, while compounds 1, 2, 4, 7-10 showed antimicrobial activity against the fungus Septoria tritici and the bacterium Escherichia coli. 相似文献