全文获取类型
收费全文 | 82篇 |
免费 | 5篇 |
专业分类
林业 | 16篇 |
农学 | 2篇 |
6篇 | |
综合类 | 8篇 |
农作物 | 4篇 |
水产渔业 | 5篇 |
畜牧兽医 | 41篇 |
植物保护 | 5篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 11篇 |
2018年 | 2篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 4篇 |
2012年 | 3篇 |
2011年 | 3篇 |
2010年 | 5篇 |
2009年 | 1篇 |
2008年 | 5篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有87条查询结果,搜索用时 15 毫秒
81.
Hans Pretzsch Kamil Bielak Joachim Block Arkadiusz Bruchwald Jochen Dieler Hans-Peter Ehrhart Ulrich Kohnle Jürgen Nagel Hermann Spellmann Michał Zasada Andreas Zingg 《European Journal of Forest Research》2013,132(2):263-280
The mixture of beech (Fagus sylvatica L.) and oak (sessile oak, Quercus petraea (Matt.) Liebl., and pedunculate oak, Q. robur L.) is of considerable importance in Europe and will probably become even more important under climate change. Therefore, the performance of oak and beech in mixture was compared with the species’ growth in pure stands. Data from 37 long-term mixing experiments in Poland, Germany and Switzerland were pooled for analysis of mixing effects on stand productivity and possible interrelationships with mixing portions or site conditions. We found that on average, mixed stands of oak and beech exceeded biomass productivity in pure stands by 30 % or 1.7 t ha?1 year?1, as the growth of both species was benefitted by the mixture. However, that the interaction actually ranged from facilitation and overyielding on poor sites to underyielding on fertile sites triggered by competition. An empirically derived interaction model showed volume and dry mass growth changing in mixed stands from gains of 50 % to losses of 10 % depending on site conditions. It is concluded that the analysed mixture grows in accordance with the stress-gradient hypothesis and that our results suggest a site-specific relationship between species mixture and biomass productivity. As a consequence, an adequate species mix should result in increased productivity under steady state as well as climate change. 相似文献
82.
83.
The aim of the current study was to evaluate the impact of carnosic acid (CA), selenised yeast (YSe) and selenate (VISe) supplemented to diets, including fish oil (FO) and rapeseed oil (RO), on the content of fatty acids, total cholesterol (TCh), tocopherols and malondialdehyde in the fat located between the thigh muscles and the heart in lambs. Twenty-four male Corriedale lambs were divided into 4 groups of 6 animals. Animals were fed a diet with FO and RO (the control diet) or experimental diets containing RO, FO and CA with/without Se (as YSe or VISe). The experimental diets without/with YSe or VISe changed concentrations of fatty acids in the fat and heart compared to the control. All experimental diets increased the levels of c11c14C20:2, c5c8c11c14C20:4, c5c8c11c14c17C20:5 and the sums of long-chain polyunsaturated fatty acids (LPUFA) and conjugated linoleic acid isomers in the fat compared to the control. The experimental diet containing YSe or VISe increased the content of Se, TCh, c11c14C20:2, c8c11c14C20:3, c5c8c11c14C20:4, c5c8c11c14c17C20:5, c7c10c13c16c19C22:5, c4c7c10c13c16c19C22:6 and the concentration sum of n-3LPUFA, n-6LPUFA and tocopherols in the heart in comparison with the control diet and the diet containing only CA. Experimental diets reduced the concentration of malondialdehyde in the fat and heart in comparison with the control diet. Our dietary intervention has great potential for future practical and commercial implementations. 相似文献
84.
Ferdaus Mohamat-Yusuff Syaizwan Zahmir Zulkifli Ahmad Ismail Hiroya Harino Mohd Kamil Yusoff Takaomi Arai 《Water, air, and soil pollution》2010,211(1-4):443-457
Thais gradata samples were collected from six locations along the southern shores of Peninsular Malaysia and analyzed for imposex incidence and organotin (butyltins (BTs), including tributyltin, dibutyltin, and monobutyltin, and phenyltins (PTs), including triphenyltin, diphenyltin, and monophenyltin concentrations), in tissue burden. On average, the BT levels were found to be higher than the levels reported a year before for other biota. In contrast, the PT compounds were found to be lower than in the previous report. The present study also classified the morphological expressions of the imposex scheme for this species into seven stages (stage 0 to stage 6) by observing the development of vas deference sequence (VDS) and penis bulk. This latest imposex scheme clearly indicates the mechanism of VDS growth, the structural changes from penis bulk to a penis with flagellum, and from a normal vaginal opening to a swollen vaginal opening. The degree of imposex was assessed using the vas deference sequence index and the percentage of females possessing the imposex characteristics. It was found that locations possessing high imposex levels also tended to show high BT levels in the snail tissue samples. However, correlation analysis did not show a significant relationship among the two parameters. A better result could be obtained if more samples and sampling locations were added in order to prove the hypothesis. The nonsignificant correlation between the shell height and any of the organotin compounds, along with no significant differences between BT levels in female and lower imposex stage samples, suggests that the BT concentration detected was a recent contamination. 相似文献
85.
86.
Jeklova E Leva L Matiasovic J Kovarcik K Kudlackova H Nevorankova Z Psikal I Faldyna M 《Veterinary microbiology》2008,129(1-2):117-130
Myxoma virus (MXV) causes the systemic disease myxomatosis in the European rabbit. Despite many in vitro studies on the function of MXV immunomodulatory proteins and detailed molecular knowledge of virus, little is known about the dynamics of interaction of the virus with the integrated host-immune system during infection. In this study changes in haematological profile, changes in lymphocyte subset distribution and non-specific proliferation activity of lymphocytes from different lymphoid compartments on the 2nd, 4th, 6th, 9th and 11th day after experimental infection of rabbits with MXV strain Lausanne was characterised. The relationship between alterations of immune parameters and dynamic of virus dissemination through the body was investigated. Haematological changes included moderate leucopenia with significant lymphopenia, neutrophilia, monocytosis and eosinopenia. A decrease of T cells including CD4+ and CD8+ and increase of CD79alpha+ were observed in draining popliteal lymph node 4 days after virus inoculation. From day 6, comparable changes were seen in collateral popliteal lymph node, spleen and peripheral blood. From day 9, the mentioned lymphocyte subsets tended to reach their original state in all of these lymphocyte compartments except draining popliteal lymph node. In thymus, MXV infection affected mainly CD4+CD8+ double positive thymocytes. On the other hand, proliferation activity of lymphocytes determined by the proliferation assay with plant-derived mitogens was significantly reduced from day 4 or 6 and remained reduced until the end of experiment in all observed lymphoid organs. Presence of MXV in respective lymphoid compartments preceded changes in lymphocyte subset distribution or lymphocyte activity. 相似文献
87.
Michael Heym Ricardo Ruíz-Peinado Miren Del Río Kamil Bielak David I. Forrester Gerald Dirnberger Ignacio Barbeito Gediminas Brazaitis Indrė Ruškytkė Lluís Coll Marek Fabrika Lars Drössler Magnus Löf Hubert Sterba Václav Hurt Viktor Kurylyak Fabio Lombardi Dejan Stojanović Jan Den Ouden Renzo Motta Maciej Pach Jerzy Skrzyszewski Quentin Ponette Géraud De Streel Vit Sramek Tomáš Čihák Tzvetan M. Zlatanov Admir Avdagic Christian Ammer Kris Verheyen Buraczyk Włodzimierz Andrés Bravo-Oviedo Hans Pretzsch 《Annals of Forest Science》2017,74(3):63