全文获取类型
收费全文 | 152篇 |
免费 | 8篇 |
专业分类
林业 | 6篇 |
农学 | 2篇 |
44篇 | |
综合类 | 10篇 |
农作物 | 2篇 |
水产渔业 | 18篇 |
畜牧兽医 | 59篇 |
园艺 | 4篇 |
植物保护 | 15篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 7篇 |
2013年 | 13篇 |
2012年 | 6篇 |
2011年 | 16篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 18篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 13篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1980年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有160条查询结果,搜索用时 46 毫秒
91.
Martin Riis Weisbjerg Mette Krogh Larsen Lone Hymøller Mette Thorhauge Ulla Kidmose Jacob Holm Nielsen Jens Bech Andersen 《Livestock Science》2013,155(1):60-70
The aim of the experiment was to study the response in milk production and composition of substituting barley with either saturated or unsaturated fat in mixed rations (MR) for dairy cows. The experiment included 35 Danish Holstein (DH), 39 Danish Red (DR), and 31 Danish Jersey (DJ) cows from parturition until week 30 of lactation. Cows were ad libitum fed one of the three MR based on maize and grass/clover silage, barley, soybean meal, and dried sugar beet pulp. In the saturated ration (SFA), C16 rich fat substituted barley on dry matter (DM) basis; in the unsaturated ration (UFA), ground rape and linseed (0.74:0.26 ratio) substituted barley on DM basis; and in the control ration (CO), no barley was substituted. Concentrations of crude fat (CF) of total ration DM was 3.03% in CO, and in diets supplemented to intended similar fat levels 5.65% (SFA) and 5.81% (UFA), respectively. Statistical analyses were performed within breed and random regression was used to test for differences between treatment responses throughout lactations. 相似文献
92.
Willerslev E Cappellini E Boomsma W Nielsen R Hebsgaard MB Brand TB Hofreiter M Bunce M Poinar HN Dahl-Jensen D Johnsen S Steffensen JP Bennike O Schwenninger JL Nathan R Armitage S de Hoog CJ Alfimov V Christl M Beer J Muscheler R Barker J Sharp M Penkman KE Haile J Taberlet P Gilbert MT Casoli A Campani E Collins MJ 《Science (New York, N.Y.)》2007,317(5834):111-114
It is difficult to obtain fossil data from the 10% of Earth's terrestrial surface that is covered by thick glaciers and ice sheets, and hence, knowledge of the paleoenvironments of these regions has remained limited. We show that DNA and amino acids from buried organisms can be recovered from the basal sections of deep ice cores, enabling reconstructions of past flora and fauna. We show that high-altitude southern Greenland, currently lying below more than 2 kilometers of ice, was inhabited by a diverse array of conifer trees and insects within the past million years. The results provide direct evidence in support of a forested southern Greenland and suggest that many deep ice cores may contain genetic records of paleoenvironments in their basal sections. 相似文献
93.
Mette D.K. Markussen 《Pesticide biochemistry and physiology》2010,98(1):50-2957
Neonicotinoids play an essential role in the control of house flies Musca domestica. The development of neonicotinoid resistance was found in two field populations. 766b was 130- and 140-fold resistant to imidacloprid and 17- and 28-fold resistant to thiamethoxam in males and females, respectively. 791a was 22- and 20-fold resistant to imidacloprid and 9- and 23-fold resistant to thiamethoxam in males and females, respectively. Imidacloprid selection of 791a increased imidacloprid resistance to 75- and 150-fold in males and females, respectively, whereas selection with thiamethoxam had minimum impact. Neonicotinoid resistance was in all cases suppressed by PBO. The cytochrome P450 genes CYP6A1, CYP6D1 and CYP6D3 were constitutively over-expressed in resistant strains and CYP6D1 and CYP6D3 differentially expressed between sexes. The highest level of CYP6A1 expression was observed in both gender of the imidacloprid-selected strain after neonicotinoid exposure. CYP6D1 expression was increased after neonicotinoid exposure in resistant males. CYP6D3 expression was induced in both sexes upon neonicotinoid exposure but significantly higher in females. 相似文献
94.
High-resolution Greenland ice core data show abrupt climate change happens in few years 总被引:1,自引:0,他引:1
Steffensen JP Andersen KK Bigler M Clausen HB Dahl-Jensen D Fischer H Goto-Azuma K Hansson M Johnsen SJ Jouzel J Masson-Delmotte V Popp T Rasmussen SO Röthlisberger R Ruth U Stauffer B Siggaard-Andersen ML Sveinbjörnsdóttir AE Svensson A White JW 《Science (New York, N.Y.)》2008,321(5889):680-684
The last two abrupt warmings at the onset of our present warm interglacial period, interrupted by the Younger Dryas cooling event, were investigated at high temporal resolution from the North Greenland Ice Core Project ice core. The deuterium excess, a proxy of Greenland precipitation moisture source, switched mode within 1 to 3 years over these transitions and initiated a more gradual change (over 50 years) of the Greenland air temperature, as recorded by stable water isotopes. The onsets of both abrupt Greenland warmings were slightly preceded by decreasing Greenland dust deposition, reflecting the wetting of Asian deserts. A northern shift of the Intertropical Convergence Zone could be the trigger of these abrupt shifts of Northern Hemisphere atmospheric circulation, resulting in changes of 2 to 4 kelvin in Greenland moisture source temperature from one year to the next. 相似文献
95.
Ståle Refstie Brett Glencross Thor Landsverk Mette Sørensen Einar Lilleeng Wayne Hawkins Åshild Krogdahl 《Aquaculture (Amsterdam, Netherlands)》2006,261(4):1382-1395
This study assessed the effects of yellow lupin (Lupinus luteus) and narrow-leafed lupin (L. angustifolius) kernel meals and protein concentrates on the gastrointestinal integrity, capacity for digestive hydrolysis, and digestibility of nutrients in Atlantic salmon. A basal diet (FM) was made from fish meal, wheat, and fish oil. Six additional diets were formulated by replacing 30% of the FM diet with lupin kernel meal made from L. l. cv. Wodjil (LKM), L. a. cv. Belara (BKM), and L. a. cv. Myallie (MKM), lupin protein concentrates made from the same L. l. (LPC) and L. a. cv. M (MPC), or extracted soybean meal (SBM). All diets were extruded. Each diet was fed to three groups of 176 g salmon kept in 1 m2 tanks with 5.6 °C saltwater for 3 weeks prior to sampling of blood, intestinal organs, digesta, and faeces. Inclusion of lupin meals in the diets resulted in harder and more condensed feed particles. Ulcer-like lesions were observed in the stomach of fish from all feeding groups, and this was worsened by lupin in the diet, but did not appear to be pellet hardness related. No consistent altered morphology was observed in the distal intestine (DI) of fish fed the FM and lupin diets, while the DI of fish fed SBM showed consistent and typical soybean meal-induced pathomorphological changes. Plasma cholesterol was higher when feeding MKM and LKM than when feeding FM, MPC, and LPC, with intermediate levels when feeding BKM and SBM. Feeding LKM and LPC resulted in a higher weight of the GIT when related to body weight. Trypsin activity and bile acid concentration were generally higher in digesta from the pyloric (PI) and mid (MI) intestine when feeding FM and lupin diets than when feeding SBM, while the opposite was seen for trypsin activity in digesta from DI. There were no effects of diet on leucine aminopeptidase (LAP) and maltase activity in PI and MI, but in DI the activity of these brush border enzymes were significantly lowered when feeding SBM. SBM in the diet resulted in watery faeces and lowered apparent digestibility of lipid, but this was not observed when feeding the lupin diets. To conclude, the tested lupin kernel meals and protein concentrates did not alter the intestinal function in Atlantic salmon when included at 30% of the diet. Dietary lupin was, however, involved in the worsening of ulcer-like gastric lesions. 相似文献
96.
Steffensen SK Pedersen HA Labouriau R Mortensen AG Laursen B de Troiani RM Noellemeyer EJ Janovska D Stavelikova H Taberner A Christophersen C Fomsgaard IS 《Journal of agricultural and food chemistry》2011,59(22):12073-12082
Amaranthus hybridus and Amaranthus mantegazzianus are commonly cultivated and the entire young fresh plants consumed as vegetables in regions of Africa and Asia. A. hybridus and A. mantegazzianus were cultivated at four sites in three climate regions of the world: Santa Rosa, Argentina; Lleida, Spain; and Prague and Olomouc, both in the Czech Republic. The contents of flavonoids (isoquercitrin, rutin, nicotiflorin), hydroxybenzoic acids (protocatechuic acid, 4-hydroxybenzoic acid, vanillic acid), hydroxycinnamic acids (caffeic acid, p-coumaric acid, ferulic acid), hydroxycinnamyl amides (N-trans-feruloyltyramine, N-trans-feruloyl-4-O-methyldopamine), and betaines (glycinebetaine, trigonelline) were determined. The variation in phytochemical content due to species and cultivation site was analyzed utilizing the multivariate statistical methods of principal component analysis (PCA) and graphical model (GM). The Argentinean samples differed from the three other locations due to higher contents of most compounds. The samples from Spain and the Czech Republic differed from each other in the content of the negatively correlated metabolites trigonelline and the flavonoids. The two amaranth species were separated primarily by a higher content of trigonelline and the two hydroxycinnamyl amides in A. mantegazzianus. The GM showed that the quantities of the different analytes within each compound group were intercorrelated except in the case of the betaines. The betaines carried no information on each other that was not given through correlations with other compounds. The hydroxycinnamic acids were a key group of compounds in this analysis as they separated the other groups from each other (i.e., carried information on all of the other groups). This study showed the contents of polyphenols and betaines in the aerial parts of vegetable amaranth to be very dependent on growth conditions, but also revealed that some of the compounds (trigonelline and the two hydroxycinnamyl amides) may be useful as features of a taxonomic classification. 相似文献
97.
98.
Pors SE Hansen MS Christensen H Jensen HE Petersen A Bisgaard M 《Veterinary microbiology》2011,150(3-4):354-361
Pasteurella multocida is a widespread respiratory pathogen in pigs associated with atrophic rhinitis and contributing to aggravation of the pulmonary lesions. The aims of the present study were to characterize isolates of P. multocida from porcine bronchopneumonia by pulsed-field gel electrophoresis (PFGE), PCR based capsular typing and multilocus sequence typing (MLST) and to compare clonal complexes outlined with the type of histological lung lesions to investigate if a correlation between clonal lineages and lesions might exist. Isolates of P. multocida were obtained from cases of cranioventrally located porcine bronchopneumonia. All lung lesions were described and classified according to histological lesions. A total of 139 isolates, from lung (n=111), pericardial sac (n=21) and kidney (n=7) of 111 pigs were described using PFGE with ApaI as the restriction enzyme. Furthermore, 20 and 29 isolates were characterized by capsular serotyping and multilocus sequence typing, respectively. PFGE demonstrated 15 different clusters showing 50% or more similarity. All selected isolates were of capsular serotype A and only three main sequence types (ST) were detected among the isolates. Associations were not found between histopathology and clonal complexes of P. multocida. In conclusion, PFGE demonstrated a high diversity of genotypes of P. multocida associated with porcine bronchopneumonia. However, isolates obtained mainly belonged to few STs, indicating that isolates of P. multocida associated with porcine bronchopneumonia originates from a limited number of clonal lineages and therefore might have adapted to porcine hosts. No correlation was demonstrated between genotypes and types of lesions, and extra-pulmonary spreading was only rarely demonstrated. 相似文献
99.
Consumer attitudes towards castration of piglets and alternatives to surgical castration 总被引:1,自引:0,他引:1
Bente Fredriksen Anne Mette Sibeko Johnsen Ellen Skuterud 《Research in veterinary science》2011,90(2):352-6791
From three in-depth focus group studies and an internet based study concerning consumers attitudes towards surgical castration of piglets and alternatives, it can be concluded that Norwegian consumers are content with the current practice of castration using local anaesthesia. They accept castration as a necessary means to prevent the risk of boar taint in meat and thereby secure meat quality. Even though castration using anaesthesia is not a perfect solution, it is considered sufficient, and the consumers do not ask for alternatives. Most consumers were sceptical of immunocastration. The scepticism was mainly based on the fear of residuals in meat and unknown long-term consequences for the consumers. On the other hand the confidence in Norwegian control authorities is considerable, and will probably contribute to the maintenance of purchase habits even if immunocastration is to be introduced in Norwegian pig production. Castration without anaesthesia was characterized as completely unacceptable. 相似文献
100.
Plasma metabolomic profiles and immune responses of piglets after weaning and challenge with E. coli