全文获取类型
收费全文 | 234篇 |
免费 | 9篇 |
专业分类
林业 | 10篇 |
农学 | 4篇 |
基础科学 | 1篇 |
68篇 | |
综合类 | 17篇 |
农作物 | 11篇 |
水产渔业 | 17篇 |
畜牧兽医 | 100篇 |
园艺 | 2篇 |
植物保护 | 13篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 10篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 7篇 |
2013年 | 14篇 |
2012年 | 12篇 |
2011年 | 21篇 |
2010年 | 11篇 |
2009年 | 7篇 |
2008年 | 20篇 |
2007年 | 20篇 |
2006年 | 19篇 |
2005年 | 9篇 |
2004年 | 6篇 |
2003年 | 12篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1980年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有243条查询结果,搜索用时 15 毫秒
151.
Spruce (Picea abies (L.) Karst) needle litter was placedin litterbags and incubated (≥6 yr) at five spruce standsin southern Sweden. The litterbags were collected twice a yearduring year 1–2 and thereafter once a year, for total analyses(conc. HNO3) of Cd, Zn, Mn, Cu and Pb. The main objectiveswere to document changes in concentrations and amounts of theseelements during litter decomposition and to investigate factorscontrolling the changes.Concentrations of Cd, Zn, Cu and Pb increased to at least 0.5, 1.5, 3 and 13 times the initial concentration. During the latterpart of the incubations, concentrations became more stable ordecreased. Concentrations at which the metals are considered to be toxic to micro-organisms in the mor layer were not reached during the experiment. Generally, concentrations of Mn decreased.Total amounts of Cd, Zn and Mn had decreased by at least15, 24 and 43%, from the initial amount at the end of theexperiment. The total amount of Cu increased (>40%) before itstarted to decrease. The total amount of Pb increased by over230%. Thereafter it became more constant or decreased.According to a PCA, the dynamics of total amounts of Cd,Zn and Mn in the litter were similar, as were those of Pb and Cu.Furthermore, in most cases the heavy metal amounts on anysampling occasion differed more between than within sites. Thedynamics of total amounts of elements were more similar betweenadjacent sites than between more distant sites. 相似文献
152.
Sonja Fonfara Udo Hetzel Mark A. Oyama Anja Kipar 《Veterinary journal (London, England : 1997)》2014,199(3):406-412
Serotonin signalling in the heart is mediated by receptor subtype 2B (5-HTR2B). A contribution of serotonin to valvular disease has been reported, but myocardial expression of 5-HTR2B and its role in canine dilated cardiomyopathy (DCM) is not known. The aim of the present study was to investigate myocardial 5-HTR2B mRNA expression in dogs with DCM and to correlate results with expression of markers for inflammation and remodelling. Myocardial samples from eight healthy dogs, four dogs with DCM, five with cardiac diseases other than DCM and six with systemic non-cardiac diseases were investigated for 5-HTR2B mRNA expression using quantitative PCR (qPCR). The results were compared to mRNA expression of selected cytokines, matrix metalloproteinases (MMP) and tissue inhibitors of matrix metalloproteinase (TIMP). Laser microdissection with subsequent qPCR and immunohistochemistry were employed to identify the cells expressing 5-HTR2B.The myocardium of control dogs showed constitutive 5-HTR2B mRNA expression. In dogs with DCM, 5-HTR2B mRNA values were significantly greater than in all other groups, with highest levels of expression in the left ventricle and right atrium. Myocytes were identified as the source of 5-HTR2B mRNA and protein. A significant positive correlation of 5-HTR2B mRNA with expression of several cytokines, MMPs and TIMPs was observed. The findings suggest that serotonin might play a role in normal cardiac structure and function and could contribute to myocardial remodelling and functional impairment in dogs with DCM. 相似文献
153.
Anja Taubert Nikola Pantchev Majda Globokar Vrhovec Christian Bauer Carlos Hermosilla 《Veterinary parasitology》2009
Faecal samples of 4151 dogs from Denmark, 958 dogs from Germany and 231 cats from Germany with clinical signs were examined for lungworm larvae using the Baermann funnel technique between 2003 and 2007. In total, 3.6% of Danish and German dogs shed lungworm larvae. In Denmark, patent infections of dogs with Angiostrongylus vasorum were more prevalent (2.2%) than those with Crenosoma vulpis (1.4%). In Denmark, the majority of A. vasorum- (98%) and C. vulpis-infected (80%) dogs originated from Northern Zealand. The frequency of A. vasorum and C. vulpis infections in Danish dogs obviously decreased from 2003 to 2006. In Germany, canine faecal samples were found more frequently positive for C. vulpis than for A. vasorum larvae (2.4% and 1.2%, respectively). Lungworm-infected dogs originated mainly from southern and western Germany. Larvae of Aelurostrongylus abstrusus were detected in 5.6% of cats from Germany. Overall, a distinct seasonal pattern in the detection of infected dogs was apparent for A. vasorum in Denmark and C. vulpis in Germany. The relatively high number of lungworm-infected dogs and cats indicate that these parasitic diseases should be considered in differential diagnosis of cases of treatment-resistant respiratory/cardiopulmonary distress. 相似文献
154.
Baldwin IT Halitschke R Paschold A von Dahl CC Preston CA 《Science (New York, N.Y.)》2006,311(5762):812-815
155.
Agnello KA Kapatkin AS Garcia TC Hayashi K Welihozkiy AT Stover SM 《Veterinary surgery : VS》2010,39(8):991-1000
Objective: To evaluate the use of a locking compression plate (LCP) with monocortical screw purchase for stabilization of the canine cervical spine. Study Design: Experimental study. Animals: Cadaveric canine cervical spine specimens (n=7). Methods: Flexion and extension bending moments were applied to canine cadaveric specimens (C3–C6) in 4‐point bending, before and after creation of a ventral slot at C4–C5, and after fixation with a 5 hole, 3.5 mm LCP with monocortical screw placement. Screw placement and penetration into the vertebral canal were determined by radiography. Range of motion, stiffness, and energy for passive physiologic loads were determined for the C3–C4, C4–C5, and C5–C6 vertebral motion units (VMU). Monotonic failure properties were determined for cervical extension. Effects of treatments on biomechanical variables were assessed using repeated measures analysis of variance and least square means (P≤.05). Results: The ventral slot procedure increased range of motion at the treated VMU. Plate fixation decreased range of motion, increased stiffness, and decreased energy at the treated VMU. No changes were observed at adjacent VMUs. None of the screws penetrated the vertebral canal. Mean (± SD) yield bending moment of plate stabilized, slotted spines was 15.6 ± 4.6 N m. Conclusion: LCP fixation with monocortical screws stabilized the canine cervical spine. 相似文献
156.
Walders B Raschke A Neugebauer M Geuther E Bertling W Reiser C Buck A Strich S Hess J 《Research in veterinary science》2005,78(2):135-141
Highly immunodominant marker antigens simply blended to existing veterinary vaccines may represent a smart approach for addressing the still open issue of vaccination compliance. This approach was evaluated by blending a widely deployed Mycoplasma hyopneumoniae vaccine with a peptide-KLH (Keyhole Limpet Hemocyanin) conjugate as marker. Piglets were vaccinated twice with: (i) a combination of the M. hyopneumoniae-specific vaccine and the marker, (ii) M. hyopneumoniae-specific vaccine, (iii) marker alone or (iv) placebo dose only. All piglets which received the M. hyopneumoniae-specific vaccine/marker formulation or, as control, the marker blended with Montanide IMS1313 adjuvant responded to the respective immunisation from day 21 to 77 post vaccination as seropositive for the appropriate peptide and KLH. However, the responder rate to M. hyopneumoniae of piglets administered with M. hyopneumoniae-specific vaccine/marker was slightly reduced at day 35 and 49 post immunisation in comparison with piglets vaccinated with M. hyopneumoniae-specific vaccine alone. Accordingly, we conclude that this marker technology could be successfully applied to label a whole set of vaccines prevented that the blending process will be optimised. 相似文献
157.
Baiting and supplemental feeding of wildlife are widespread, yet highly controversial management practices, with important implications for ecosystems, livestock production, and potentially human health. An often underappreciated threat of such feeding practices is the potential to facilitate intra- and inter-specific disease transmission. We provide a comprehensive review of the scientific evidence of baiting and supplemental feeding on disease transmission risk in wildlife, with an emphasis on large herbivores in North America. While the objectives of supplemental feeding and baiting typically differ, the effects on disease transmission of these practices are largely the same. Both feeding and baiting provide wildlife with natural or non-natural food at specific locations in the environment, which can result in large congregations of individuals and species in a small area and increased local densities. Feeding can lead to increased potential for disease transmission either directly (via direct animal contact) or indirectly (via feed functioning as a fomite, spreading disease into the adjacent environment and to other animals). We identified numerous diseases that currently pose a significant concern to the health of individuals and species of large wild mammals across North America, the spread of which are either clearly facilitated or most likely facilitated by the application of supplemental feeding or baiting. Wildlife diseases also have important threats to human and livestock health. Although the risk of intra- and inter-species disease transmission likely increases when animals concentrate at feeding stations, only in a few cases was disease prevalence and transmission measured and compared between populations. Mostly these were experimental situations under controlled conditions, limiting direct scientific evidence that feeding practices exacerbates disease occurrence, exposure, transmission, and spread in the environment. Vaccination programs utilizing baits have received variable levels of success. Although important gaps in the scientific literature exist, current information is sufficient to conclude that providing food to wildlife through supplemental feeding or baiting has great potential to negatively impact species health and represents a non-natural arena for disease transmission and preservation. Ultimately, this undermines the initial purpose of feeding practices and represents a serious risk to the maintenance of biodiversity, ecosystem functioning, human health, and livestock production. Managers should consider disease transmission as a real and serious concern in their decision to implement or eliminate feeding programs. Disease surveillance should be a crucial element within the long-term monitoring of any feeding program in combination with other available preventive measures to limit disease transmission and spread. 相似文献
158.
González-Rey C Svenson SB Bravo L Siitonen A Pasquale V Dumontet S Ciznar I Krovacek K 《Comparative immunology, microbiology and infectious diseases》2004,27(2):129-139
A total of 73 strains of Plesiomonas shigelloides isolated from humans (24 strains) animals (21 strains) and aquatic environment (28 strains) were determined for their O:H serotype and susceptibility to 18 anti-microbial substances and to the vibriostatic agent O/129. Of all strains, 86.3% were typeable by the O and 94.5% by the H anti-sera used. The serotype distribution was heterogeneous within a country and between the countries. Of the 57 different serotypes identified, O11:H2 (2 strains), O22:H3 (4 strains), O35:HH11 (2 strains), O52:H3 (2 strains) and O90:H6 (2 strains) were found among isolates from humans and animals (mainly in cats) in Finland and Cuba, and O23:H1a1b (3 strains) among isolates from environmental sources in Slovak Republic and Italy. Most (93-100%) of all strains were susceptible to all anti-microbials tested but resistant (92-96%) to the broad-spectrum penicillins (ampicillin, mezlocillin). No correlation between anti-microbial resistance patterns and serotypes was found. 相似文献
159.
The effect of fermentable carbohydrates on experimental swine dysentery and whip worm infections in pigs 总被引:1,自引:0,他引:1
Thomsen LE Knudsen KE Jensen TK Christensen AS Møller K Roepstorff A 《Veterinary microbiology》2007,119(2-4):152-163
An experiment was conducted to study the effect of diets with contrasting fermentability in the large intestine on experimental infections with Brachyspira hyodysenteriae, the causative agent of swine dysentery, and the whip worm, Trichuris suis, in pigs. Two diets with organically grown ingredients were composed. Both diets were based on triticale and barley and supplemented with either rape seed cake (Diet 1) or dried chicory root and sweet lupins (Diet 2). The study had a three-factorial design, with eight groups of pigs receiving Diet 1 or Diet 2, +/-B. hyodysenteriae, and +/-T. suis. Pigs fed Diet 2 and challenged with B. hyodysenteriae did not develop swine dysentery and B. hyodysenteriae was not demonstrated in any of the pigs during the study. In contrast, 94% of the B. hyodysenteriae challenged pigs fed Diet 1 showed clinical symptoms of swine dysentery and all the pigs were shedding B. hyodysenteriae in faeces at some points in time during the experiment. The number of T. suis was lower in pigs fed Diet 2 compared to pigs fed Diet 1, but the differences were not significant. Pigs on Diet 1 and challenged with both pathogens showed clinical symptoms of SD for a longer period than pigs inoculated with B. hyodysenteriae only. The study showed that diets supplemented with highly fermentable carbohydrates from dried chicory roots and sweet lupins can protect pigs against developing swine dysentery, but do not have any significant influence on T. suis. 相似文献
160.