全文获取类型
收费全文 | 387篇 |
免费 | 20篇 |
专业分类
林业 | 25篇 |
农学 | 11篇 |
93篇 | |
综合类 | 50篇 |
农作物 | 25篇 |
水产渔业 | 37篇 |
畜牧兽医 | 128篇 |
园艺 | 13篇 |
植物保护 | 25篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 18篇 |
2020年 | 21篇 |
2019年 | 16篇 |
2018年 | 10篇 |
2017年 | 17篇 |
2016年 | 27篇 |
2015年 | 16篇 |
2014年 | 14篇 |
2013年 | 11篇 |
2012年 | 34篇 |
2011年 | 42篇 |
2010年 | 15篇 |
2009年 | 20篇 |
2008年 | 18篇 |
2007年 | 24篇 |
2006年 | 16篇 |
2005年 | 16篇 |
2004年 | 22篇 |
2003年 | 10篇 |
2002年 | 16篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有407条查询结果,搜索用时 15 毫秒
361.
Alessandro Pirrone Carolina CastagnettiJole Mariella DVM PhD Cristina BonoliLaura Stancampiano DVM Maria Paola TampieriRoberta Galuppi DVM 《Journal of Equine Veterinary Science》2012
Little is known about the normal or pathologic yeast flora in healthy and critically ill neonatal foals. The aims of this study were to evaluate the yeast flora colonizing the mucous membranes of the digestive tract (oropharynx and rectum mucous membranes) of healthy and hospitalized foals and to find out risk factors involved in yeast colonization of foals referred to a neonatal intensive care unit. A total of 240 swabs were collected from 21 healthy (group A) and 39 sick (group B) foals. In 14 of the 60 foals, yeast was isolated in at least one sample (23.3%): 3 of the 21 foals (14.3%) were positive in group A and 11 of 39 foals (28.2%) were positive in group B. The yeasts were isolated from rectal swabs obtained from none in healthy foals, whereas 5 of the 39 sick foals were positive; however, this difference was not statistically significant. No significant difference was also detected regarding oropharyngeal swabs between healthy (3/21) and sick (10/39) foals. The risk factors significantly associated with the isolation of yeasts from rectal swabs were female sex, treatment with oral antibiotics, and stressful diagnostic–therapeutic procedures. The only risk factor significantly associated with the isolation of yeast from oropharyngeal swabs was the treatment with antacids and gastroprotectants. The results show that fungi present in the gastrointestinal tract of neonatal foals were mainly environmental yeasts and suggested the absence of a stable fungal colonization. Candida was the genus frequently isolated in hospitalized foals, just as it is isolated in critically ill human neonates. 相似文献
362.
Lamagna B Peruccio C Guardascione A Paciello O Costagliola A Giudice C Rondena M Saccone M Uccello V Lamagna F 《Veterinary ophthalmology》2012,15(3):194-199
Two 5-month-old golden retriever dogs were referred for the evaluation of a mass arising from the left ventrolateral conjunctiva of the lower eyelid. The masses were externally located, deemed to be cystic in nature, and were surgically removed, and in one case, 0.15 mL of clear fluid was collected. Cytological examination of the aspirated fluid revealed proteinaceous, basophilic amorphous material, and few epithelial cells with foamy cytoplasm and small nuclei. No micro-organisms were detected. Histological examination of the cysts showed a wall composed of single to double cell layers. The cells were cuboidal to flattened, nonciliated, lined with mild submucosal connective tissues and slight inflammation composed of lymphocytes, plasma cells, and rare macrophages. In some areas, lobules of acinar glandular tissue were observed. To the authors' knowledge, this is the first case report of conjunctival dacryops in dogs. The complete surgical removal of the cysts was curative in both cases. 相似文献
363.
364.
A flexible unmanned aerial vehicle for precision agriculture 总被引:1,自引:0,他引:1
Jacopo Primicerio Salvatore Filippo Di Gennaro Edoardo Fiorillo Lorenzo Genesio Emanuele Lugato Alessandro Matese Francesco Primo Vaccari 《Precision Agriculture》2012,13(4):517-523
An unmanned aerial vehicle (??VIPtero??) was assembled and tested with the aim of developing a flexible and powerful tool for site-specific vineyard management. The system comprised a six-rotor aerial platform capable of flying autonomously to a predetermined point in space, and of a pitch and roll compensated multi-spectral camera for vegetation canopy reflectance recording. Before the flight campaign, the camera accuracy was evaluated against high resolution ground-based measurements, made with a field spectrometer. Then, ??VIPtero?? performed the flight in an experimental vineyard in Central Italy, acquiring 63 multi-spectral images during 10?min of flight completed almost autonomously. Images were analysed and classified vigour maps were produced based on normalized difference vegetation index. The resulting vigour maps showed clearly crop heterogeneity conditions, in good agreement with ground-based observations. The system provided very promising results that encourage its development as a tool for precision agriculture application in small crops. 相似文献
365.
Ressel L Finotello R Innocenti VM Vannozzi I Poli A 《Research in veterinary science》2012,93(1):343-349
Leptin and its receptor (ObR) expression were investigated by immunohistochemistry in normal, hyperplastic and neoplastic canine mammary tissues and related to clinical-pathological features. Leptin expression was detected in healthy mammary tissues, adenosis and in benign mammary tumours and was lower in ductal hyperplasias and malignant tumours. A high percentage of ObR-positive cells were present in adenosis, benign tumours and in complex carcinomas, while ObR expression was lower in healthy mammary tissues, in ductal hyperplasias and in a large part of invasive mammary carcinomas. Our data demonstrated that cancer cells expressed at low level leptin and ObR in canine mammary tumours with a more aggressive behaviour, as well as in lymph node metastases. Consequently, leptin and ObR expressions in this species resulted to be not associated with a reduced overall survival. 相似文献
366.
367.
Alessandro Vitale Gabriella Cirvilleri Anna Panebianco Filomena Epifani Giancarlo Perrone Giancarlo Polizzi 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(4):483-487
Thirty-two isolates belonging to black aspergilli (Aspergillus section Nigri) associated to vine canker disease of grapevine were collected in seven vineyards located in southeastern Sicily (Italy).
Molecular analysis was performed to identify the isolates by multilocus sequence analysis. Amplification of part of the β-tubulin
gene (benA) and partial calmodulin (CaM) gene were performed using the Bt2a, Bt2b and CL1, CL2A primers, respectively. Molecular characterisation showed a high distribution
of Aspergillus niger “aggregate” species on grapes in Sicily and in particular of A. niger (21 isolates), A. tubingensis (9 isolates), and A. carbonarius (2 isolates). The 21 isolates of A. niger found to belong within the newly described cryptic species A. awamori. Six isolates (3 of A. tubingensis, 2 of A. carbonarius, and 1 of A. niger) were used in pathogenicity studies on mature canes of cv. Italia grape. All species caused Aspergillus vine canker equally
well, with no differences in virulence. 相似文献
368.
Trees outside forests (TOF) are important elements of the landscape and they supply goods and environmental services such as commercial production of timber and fibre, domestic production of food and firewood, carbon sequestration, conservation of habitats and species (plants and animals), erosion control and soil and water quality improvement. TOF include different types of landscape elements: small woodlands, trees along linear features such as property boundaries, roads, railways, rivers and canals, hedgerows or linear forest formations, groups of trees and isolated scattered trees, which have also different ecological functions. The article focuses on the importance and role of linear forest formations (LFF) in the rural context, with special reference to the biodiversity conservation function. It presents the results of research done in the Veneto region, north-eastern Italy. The authors have designed a sampling scheme for LFF based on the Italian National Forest Inventory and tested an indicator system in order to evaluate the quality and biodiversity of the LFF. The indicators used are: LFF type and tree species composition, vertical structure and canopy cover, naturalness, introduced species and deadwood (standing and lying). The main advantages and limitations of the applied method are discussed. 相似文献
369.
Carvalho CO Chagas AC Cotinguiba F Furlan M Brito LG Chaves FC Stephan MP Bizzo HR Amarante AF 《Veterinary parasitology》2012,183(3-4):260-268
The indiscriminate use of anthelmintics has resulted in the establishment of parasite resistance. Thus, this study aimed to evaluate the in vitro antiparasitic effect of plant extracts on Haemonchus contortus in sheep and the in vivo effect on Strongyloides venezuelensis in Rattus norvegicus. The plant extracts from Piper tuberculatum, Lippia sidoides, Mentha piperita, Hura crepitans and Carapa guianensis, produced at different research institutions, were chemically analyzed and evaluated through the egg hatch test (EHT) and larval development test (LDT) in H. contortus. P. tuberculatum (150 and 250 mg kg(-1) of body weight) was evaluated for its anthelmintic action on R. norvegicus experimentally infected with S. venezuelensis. In the EHT, the LC(50) and LC(90) of the extracts were respectively as follows: 0.031 and 0.09 mg mL(-1) for P. tuberculatum, 0.04 and 0.13 mg mL(-1) for L. sidoides, 0.037 and 0.10 mg mL(-1) for M. piperita, 2.16 and 17.13 mg mL(-1) for H. crepitans and 2.03 × 10(-6) and 1.22 × 10(-12) mg mL(-1) for C. guianensis. In the LDT, the LC(50) and LC(90) were respectively: 0.02 and 0.031 mg mL(-1) for P. tuberculatum, 0.002 and 0.04 mg mL(-1) for L. sidoides, 0.018 and 0.03 mg mL(-1) for M. piperita, 0.36 and 0.91 mg mL(-1) for H. crepitans and 17.65 and 1890 mg mL(-1) for C. guianensis. The extract of P. tuberculatum showed the following substances: piperamides as (Z)-piplartine, (E)-piplartine, 8,9-dihydropiplartine, piperine, 10,11-dihydropiperine, 5,6 dihydropiperlongumine and pellitorine. The major compounds of the oils were thymol (76.6%) for L. sidoides, menthol (27.5%) for M. piperita and oleic acid (46.8%) for C. guianensis. Regarding the in vivo test, neither dose of P. tuberculatum caused any significant reduction (P>0.05) in worm burden and fecal egg counts compared with the control group. We conclude that the extracts of P. tuberculatum, L. sidoides and M. piperita have effective activity when tested in vitro, but the doses of the extract of P. tuberculatum have no effect when employed in in vivo tests. 相似文献
370.
De Simoi A 《Journal of veterinary dentistry》2006,23(2):89-95
A 9-year-old, male North African leopard (Panhtera pardus) presented with mandibular brachygnathism and lingually displaced mandibular canine teeth causing a large left oronasal fistula, rhinitis and nasal discharge, and a right orocutaneous fistula. Surgical closure of the left oronasal defect, bilateral mandibular canine tooth crown reduction, and root canal therapy resulted in a positive clinical outcome. A small recurrent left oronasal fistula and the right orocutaneous fistula healed spontaneously after alleviating the occlusal contact with the mandibular canine teeth. At 12-months postoperatively, clinical signs of oral and dental disease had resolved. 相似文献