全文获取类型
收费全文 | 373篇 |
免费 | 6篇 |
专业分类
林业 | 10篇 |
农学 | 6篇 |
基础科学 | 3篇 |
45篇 | |
综合类 | 36篇 |
农作物 | 35篇 |
水产渔业 | 17篇 |
畜牧兽医 | 211篇 |
园艺 | 2篇 |
植物保护 | 14篇 |
出版年
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2014年 | 8篇 |
2013年 | 19篇 |
2012年 | 15篇 |
2011年 | 21篇 |
2010年 | 12篇 |
2009年 | 6篇 |
2008年 | 27篇 |
2007年 | 13篇 |
2006年 | 20篇 |
2005年 | 24篇 |
2004年 | 19篇 |
2003年 | 22篇 |
2002年 | 27篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1993年 | 2篇 |
1991年 | 4篇 |
1989年 | 2篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1970年 | 8篇 |
1969年 | 4篇 |
1968年 | 3篇 |
1967年 | 4篇 |
1964年 | 3篇 |
1961年 | 2篇 |
1945年 | 2篇 |
1944年 | 6篇 |
1943年 | 10篇 |
排序方式: 共有379条查询结果,搜索用时 15 毫秒
81.
Oglesby PA Joubert KE Meiring T 《Journal of the South African Veterinary Association》2006,77(3):160-163
Amitraz is a formamidine compound used in veterinary medicine as a topical dip to control ticks and mites on dogs and livestock. A 10-year-old female Scottish terrier was presented following the accidental oral administration of a dip containing amitraz. This case report describes the clinical signs, treatment and pathology of this dog. Clinical signs of toxicity from amitraz result from stimulation of alpha2-adrenergic receptors. Amitraz is seldom fatal because the effects can be reversed by alpha2-adrenergic antagonists. The dog recovered from the amitraz toxicity but died 5 days later from acute renal failure. 相似文献
82.
Anaesthesia and analgesia for dogs and cats in South Africa undergoing sterilisation and with osteoarthritis--an update from 2000 总被引:1,自引:0,他引:1
Joubert KE 《Journal of the South African Veterinary Association》2006,77(4):224-228
A survey was conducted in 2000 into the use of analgesic drugs by veterinarians in South Africa. This survey was repeated in 2005 to establish whether the use of analgesic drugs has increased and which analgesic drugs are being used for acute pain and osteoarthritis. The number of sterilisations performed and the number of new cases of osteoarthritis in dogs and cats was estimated. It is estimated that approximately 260000 cats are operated on each year in South Africa and that 150000 cats are sterilised. Five hundred thousand dogs undergo surgery, of which 242000 are sterilised. It appears that the number of surgical procedures performed in South Africa has decreased. The estimated death rate following anaesthesia has remained unchanged at 1:1004. Overall, the use of analgesics by South African veterinarians has increased significantly. Fifty-six per cent of cats and 74% of dogs were given peri-operative analgesics but this increased to 94% and 84% after including pre-anaesthetic medications with analgesic properties. The use of opioids (morphine and buprenorphine) and propofol has increased significantly. Approximately 253000 dogs and 33000 cats with osteoarthritis are seen by veterinarians in South Africa annually. The recognition by veterinarians of osteoarthritis in cats appears to be poor and is in need of attention. Carprofen and glucosamine/chondroitin are the most commonly used agents for the treatment of osteoarthritis. Details of the drugs used by veterinarians are given. Knowledge of analgesic drugs has increased significantly over the last 5 years. Continuing education is thought to have played an important role in the changes reported in this study. 相似文献
83.
Cordeau ME Joubert P Dewachi O Hamid Q Lavoie JP 《Veterinary immunology and immunopathology》2004,97(1-2):87-96
Heaves is a common condition of horses of cold climate that is characterized by small airway inflammation and obstruction following exposure of susceptible horses to moldy hay and straw. It has been shown that helper T lymphocytes (Th) orchestrate the inflammatory response in asthma and in various animal models of allergic lung diseases by the release of Th2-type cytokines. Results of previous studies indicate that a predominant expression of Th2-type response by airway cells may also be present in heaves. To evaluate the temporal mRNA expression of Th1 (IFN-gamma) and Th2 (IL-4, IL-5) type cytokines in heaves and their relationship to clinical disease, we studied the pulmonary mechanics and cytokine mRNA expression (IL-4, IL-5 and IFN-gamma) in bronchoalveolar lavage lymphocytes of horses with heaves (n=6) and control (n=6) before and after 24h and 9 days of continuous natural inhalation challenge. Starting 24h after challenge horses with heaves, but not control horses, had a significant increase in pulmonary elastance and the number of lymphocytes expressing mRNA for IL-4 and IL-5. These changes were further increased at 9 days, at which time the number of cells positive for IFN-gamma mRNA was decreased. In this study we have shown that BAL lymphocytes of horses with heaves during clinical exacerbation have a predominant Th2-type cytokine response and that this response coincides in time with the presence of airway obstruction. 相似文献
84.
85.
Mark D. Christopher Shuyu Liu Marla D. Hall David S. Marshall Myron O. Fountain Jerry W. Johnson Eugene A. Milus Kimberly A. Garland‐Campbell Xianming Chen Carl A. Griffey 《Plant Breeding》2013,132(1):53-60
Little is known about the extent or diversity of resistance in soft red winter wheat (Triticum aestivum L.) to stripe rust, caused by the fungal pathogen Puccinia striiformis f.sp. tritici. The soft red winter (SRW) wheat cultivar ‘USG 3555’ has effective adult‐plant resistance to stripe rust, which was characterized in a population derived from ‘USG 3555’/‘Neuse’. The mapping population consisted of 99 recombinant inbred lines, which were evaluated for stripe rust infection type (IT) and severity to race PST‐100 in field trials in North Carolina in 2010 and 2011. Genome‐wide molecular‐marker screenings with 119 simple sequence repeats and 560 Diversity Arrays Technology (DArT) markers were employed to identify quantitative trait loci (QTL) for stripe rust resistance. QTL on chromosomes 1AS, 4BL and 7D of ‘USG 3555’ explained 12.8, 73.0 and 13.6% of the variation in stripe rust IT, and 13.5, 72.3 and 10.5% of the variation in stripe rust severity, respectively. Use of these and additional diagnostic markers for these QTL will facilitate the introgression of this source of stripe rust resistance into SRW wheat lines via marker‐assisted selection. 相似文献
86.
de Beer D Joubert E Marais J Manley M 《Journal of agricultural and food chemistry》2006,54(8):2897-2905
The total antioxidant capacity (TAC) and phenolic composition of 139 Pinotage wines (2002 and 2003 vintages) were determined using the 2,2'-azino-di(3-ethylbenzo-thialozine-sulfonic acid) scavenging assay and high-performance liquid chromatography, respectively. The contribution of individually quantified phenolic compounds to the wine TAC was calculated using their concentrations and Trolox equivalent antioxidant capacity (TEAC) values. The TEAC values of quercetin-3-galactoside, isorhamnetin, and peonidin-3-glucoside are reported for the first time. Between 11 and 24% of the measured TAC of Pinotage wines was explained by the sum of the calculated contributions of their quantified phenolic compounds comprising monomeric phenolic compounds and procyanidin B1. Ultrafiltration was carried out to attempt separation of monomeric and polymeric phenolic compounds. Analysis of ultrafiltration permeates and retentates enabled estimation of the TAC contribution of large molecular weight (MW) unknown compounds (46%) (>50 kDa), including oligomeric and polymeric phenolic compounds and small MW unknown compounds (34%) (<50 kDa). Three mixtures, containing 12 phenolic compounds in typical concentrations expected in Pinotage wines, exhibited 16-23% synergistic antioxidant activity. This suggests that synergy between phenolic compounds does play a role in the wine TAC but that it does not explain the large discrepancy between measured and calculated TAC values. 相似文献
87.
Kamara BI Brand DJ Brandt EV Joubert E 《Journal of agricultural and food chemistry》2004,52(17):5391-5395
Cyclopia subternata is one of the 24 Cyclopia species that are used to brew honeybush tea, a unique South African herbal beverage with a pleasant taste and flavor. It contains various antioxidants, very low tannin content, and no caffeine. Many health properties are associated with regular consumption of the tea. Honeybush infusions have been noted as a tonic for colds and influenza, catarrh, and pulmonic tuberculosis and is becoming well-known for its effectiveness in alleviating menopausal symptoms in women. "Unfermented" leaves of C. subternata contain pinitol, shikimic acid, p-coumaric acid, 4-glucosyltyrosol, epigallocatechin gallate, the isoflavone orobol, the flavanones hesperedin, narirutin, and eriocitrin, a glycosylated flavan, the flavones luteolin, 5-deoxyluteolin, and scolymoside, the xanthone mangiferin, and the flavonol C-6-glucosylkaempferol. The structures were elucidated by spectroscopic and spectrometric analysis. 相似文献
88.
Kenneth Miller Brenna J. Aegerter Nicholas E. Clark Michelle Leinfelder-Miles Eugene M. Miyao Richard Smith 《Communications in Soil Science and Plant Analysis》2019,50(1):77-92
Soil nitrogen (N) mineralization rates from different agricultural regions in California were determined and related to soil properties. Undisturbed soil cores were sampled in spring from 57 fields under annual crop rotations and incubated at 25℃ for 10 weeks. Soil properties varied across and within regions, most notably those related to soil organic matter (SOM), with total soil carbon ranging from 6 to 198 g kg?1. Multivariate linear regression was used to select soil properties that best predicted N mineralization rates. Regression models with a good fit differed between soils with high and low SOM contents, but generally included a measure of SOM quantity, its quality as well as soil texture or mineralogy. Adjusted R2 values were 0.95 and 0.60 for high and low SOM soils, respectively. This study has shown that information on soil properties can contribute to better estimates of N mineralization in soils of contrasting characteristics. 相似文献
89.
Joubert E Manley M Gray BR Schulz H 《Journal of agricultural and food chemistry》2005,53(9):3493-3502
The effect of drying conditions on harpagoside (HS) retention, as well as the use of near-infrared spectroscopy (NIRS) for rapid quantification of the iridoids, HS, and 8-rho-coumaroyl harpagide (8rhoCHG) and moisture, in dried Harpagophytum procumbens (devil's claw) root was investigated. HS retention was significantly (P < 0.05) lower in sun-dried samples as compared to tunnel-dried (60 degrees C, 30% relative humidity) and freeze-dried samples. The best retention of HS was obtained at 50 degrees C when evaluating tunnel drying at dry bulb temperatures of 40, 50, and 60 degrees C and 30% relative humidity. NIRS can effectively predict moisture content with a standard error of prediction (SEP) and correlation coefficient (r) of 0.24% and 0.99, respectively. The HS and 8rhoCHG NIRS calibration models established for both iridoid glucosides can be used for screening purposes to get a semiquantitative classification of devil's claw roots (for HS: SEP = 0.236%, r = 0.64; for 8rhoCHG: SEP = 0.048%, r = 0.73). 相似文献
90.
Joubert E Winterton P Britz TJ Gelderblom WC 《Journal of agricultural and food chemistry》2005,53(26):10260-10267
Unfermented rooibos tea is known to contain higher levels of total polyphenols and flavonoids than its fermented counterpart, making it the obvious choice for the preparation of flavonoid-enriched fractions. Evaluation of aqueous extracts and crude polyphenolic fractions of unfermented and fermented rooibos showed anti- and/or pro-oxidant activities, using a linoleic acid-Tween-buffer emulsion for lipid peroxidation and the deoxyribose degradation assay, based on a Fenton reaction model system containing FeCl3-EDTA and H2O2 for the generation of hydroxyl radicals. Except for the ethyl acetate fraction, with the highest total polyphenol (TP) content and offering the least protection presumably due to pro-oxidant activity, the inhibition of lipid peroxidation by the samples correlated moderately with their TP content in a linear relationship (r = 0.896, P < 0.01). Using the deoxyribose degradation assay, the pro-oxidant activity of the aqueous extracts and their crude polymeric fractions (0.1 mg/mL in the reaction mixture) was linear with respect to their dihydrochalcone (aspalathin and nothofagin) (r = 0.977, P = 0.023) and flavonoid (r = 0.971, P = 0.029) content. Pro-oxidant activity was demonstrated for pure aspalathin. Using the same assay, but with ascorbate added to regenerate Fe3+ to Fe2+, the aqueous extract and crude polymeric fraction of fermented rooibos displayed hydroxyl radical scavenging activity. Fermentation (i.e., oxidation) of rooibos decreased the pro-oxidant activity of aqueous extracts, which was contributed to a decrease in their dihydrochalcone content. The in vitro pro-oxidant activity displayed by flavonoid-enriched fractions of rooibos demonstrates that one must be aware of the potential adverse biological properties of potent antioxidant extracts utilized as dietary supplements. 相似文献