全文获取类型
收费全文 | 373篇 |
免费 | 32篇 |
专业分类
林业 | 34篇 |
农学 | 12篇 |
基础科学 | 2篇 |
89篇 | |
综合类 | 16篇 |
农作物 | 20篇 |
水产渔业 | 65篇 |
畜牧兽医 | 124篇 |
园艺 | 13篇 |
植物保护 | 30篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 20篇 |
2020年 | 26篇 |
2019年 | 16篇 |
2018年 | 18篇 |
2017年 | 12篇 |
2016年 | 17篇 |
2015年 | 16篇 |
2014年 | 14篇 |
2013年 | 28篇 |
2012年 | 23篇 |
2011年 | 38篇 |
2010年 | 22篇 |
2009年 | 14篇 |
2008年 | 23篇 |
2007年 | 16篇 |
2006年 | 24篇 |
2005年 | 10篇 |
2004年 | 14篇 |
2003年 | 12篇 |
2002年 | 11篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1981年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有405条查询结果,搜索用时 15 毫秒
101.
Evaluation of the influence of thermal oxidation on the phenolic composition and on the antioxidant activity of extra-virgin olive oils 总被引:1,自引:0,他引:1
Carrasco-Pancorbo A Cerretani L Bendini A Segura-Carretero A Lercker G Fernández-Gutiérrez A 《Journal of agricultural and food chemistry》2007,55(12):4771-4780
A comparison between the results obtained by using HPLC-UV, HPLC-MS, and CE-UV for characterizing the deterioration of extra-virgin olive oil during heating (180 degrees C) was investigated, taking into account phenolic compounds. The concentration of several compounds belonging to four families of phenols (simple phenols, lignans, complex phenols, and phenolic acids) was determined in the samples after the thermal treatment by all three techniques. Hydroxytyrosol, elenolic acid, decarboxymethyl oleuropein aglycon, and oleuropein aglycon reduced their concentration with the thermal treatment more quickly than other phenolic compounds present in olive oil. HYTY-Ac and Lig Agl were demonstrated to be quite resistant to this kind of treatment, and the behavior of lignans could be outstanding, as they belong to the family most resistant to thermal treatment. Several "unknown" compounds were determined in the phenolic profiles of the oils after the thermal treatment, and their presence was confirmed in refined olive oils. The oxidative stability index (OSI time) was reduced from 25 to 5 h after 3 h of heating, whereas the peroxide value showed a minimum after 1 h of heating. 相似文献
102.
Chiavaro E Vittadini E Rodriguez-Estrada MT Cerretani L Bonoli M Bendini A Lercker G 《Journal of agricultural and food chemistry》2007,55(26):10779-10786
Thermal properties of monovarietal extra virgin olive oils were evaluated by means of differential scanning calorimetry (upon cooling) and related to their chemical composition (triacylglycerols, diacylglycerols, total and free fatty acids, oxidation status). The overall crystallization enthalpy did not significantly differ among samples and did not account for the differences observed in chemical compositions. On the contrary, a higher degree of unsaturation in the lipid profile induced a shift of the crystallization onset towards lower temperatures and narrowing of the crystallization temperature range. The presence of triacylglycerol lysis and lipid oxidation products shifted the crystallization towards higher temperatures and the phase transition developed over a larger temperature range. Differential scanning calorimetry thermograms were deconvoluted into three constituent exothermic peaks for all samples. The area of the two lower-temperature exotherms was found to be statistically correlated with the amount of triunsaturated and monosaturated triacylglycerols present in the oil. Thermal properties of extra virgin olive oil were found to be affected by oil chemical composition. 相似文献
103.
OBJECTIVE: To report use of combined spinal epidural anesthesia for tail resection and surgical exploration of the pelvic canal and the perineal-pararectal area in a dog. ANIMAL: A 4-month-old, 13 kg male Collie dog. METHODS: Under inhalant anesthesia, an epidural catheter was threaded through a Tuohy needle at L5-L6. Then using a Whitacre spinal needle bupivacaine and fentanyl were administered in the subarachnoid space at L6-L7 level. Fifteen minutes later, morphine was administered epidurally. Bupivacaine and morphine were administered epidurally 4 hours after the subarachnoid injection. RESULTS: No cardiorespiratory response to surgical stimulation was observed. Postoperative analgesia was satisfactory, and the catheter was removed 30 hours later. No complications or neurologic sequelae occurred before discharge or were noted 10 days later. CONCLUSION: Combined spinal-epidural anesthesia provided excellent intraoperative anesthesia and perioperative analgesia in a dog undergoing surgery involving the pelvic canal. CLINICAL RELEVANCE: Combined spinal-epidural anesthesia can be performed in dogs, and its use should be considered in major surgeries caudal to the diaphragm, as the epidural catheter allows cranial extension of the block, providing excellent intraoperative anesthesia and perioperative analgesia. 相似文献
104.
Tufária Mussá Carolina Rodríguez-Cari?o Alejandro Sánchez-Chardi Massimiliano Baratelli Mar Costa-Hurtado Lorenzo Fraile Javier Domínguez Virginia Aragon María Montoya 《Veterinary research》2012,43(1):80
Pigs possess a microbiota in the upper respiratory tract that includes Haemophilus parasuis. Pigs are also considered the reservoir of influenza viruses and infection with this virus commonly results in increased impact of bacterial infections, including those by H. parasuis. However, the mechanisms involved in host innate responses towards H. parasuis and their implications in a co-infection with influenza virus are unknown. Therefore, the ability of a non-virulent H. parasuis serovar 3 (SW114) and a virulent serovar 5 (Nagasaki) strains to interact with porcine bone marrow dendritic cells (poBMDC) and their modulation in a co-infection with swine influenza virus (SwIV) H3N2 was examined. At 1 hour post infection (hpi), SW114 interaction with poBMDC was higher than that of Nagasaki, while at 8 hpi both strains showed similar levels of interaction. The co-infection with H3N2 SwIV and either SW114 or Nagasaki induced higher levels of IL-1β, TNF-α, IL-6, IL-12 and IL-10 compared to mock or H3N2 SwIV infection alone. Moreover, IL-12 and IFN-α secretion differentially increased in cells co-infected with H3N2 SwIV and Nagasaki. These results pave the way for understanding the differences in the interaction of non-virulent and virulent strains of H. parasuis with the swine immune system and their modulation in a viral co-infection. 相似文献
105.
Andrea Coppi Lorenzo Cecchi Federico Selvi Mauro Raffaelli 《Genetic Resources and Crop Evolution》2010,57(7):1041-1052
DNA sequences from the ITS region of the nuclear genome and Inter-Simple Sequence Repeat markers (ISSR) were used to estimate
genetic diversity among and within populations of the Frankincense tree Boswellia sacra from Dhofar, Oman. This is a culturally and ecologically relevant species that is showing symptoms of decline due to anthropic
factors and, possibly, global warming. ITS sequences were 511 bp long and showed low (6.4%) variation among geographically
different populations. The four selected ISSR primers yielded 93 reproducible bands, of which 91 (97.9%) were polymorphic
in the 97 individual profiles obtained. Total genetic diversity (H
T) and average heterozygosity within populations (H
S) resulted fairly low (0.22 and 0.136, respectively). The accession from Wadi Dowkah, an UNESCO world heritage site, showed
the lowest level of genetic diversity (H
E = 0.107), while the eastern populations from the Hasik area harboured a slightly greater amount of variation. Analysis of
Molecular Variance showed that differentiation among populations was relatively high (38.1%), possibly due to the reduced
gene flow between the largely isolated stands of Boswellia (N
m = 0.39). Genetic distances and AMOVA suggested a clear differentiation between the eastern and western coastal populations,
while those from the internal area did not form a consistent group. For conservation, the eastern sites should be given priority
as core populations harbouring significant amounts of allelic diversity. Reasons for reinforcing the more depauperated stands,
such as Wadi Dowkah, with local plant material only or, alternatively, with the introduction of germplasm from genetically
distinct stands are discussed. 相似文献
106.
107.
108.
Phaeomoniella chlamydospora (Pch) and Togninia minima (Tmi) produced scytalone, isosclerone and pullulans in liquid cultures, as well as in calli. Secondary metabolites and host defense compounds were shown to occur in calli of Vitis vinifera cv. Italia and cv. Matilde infected by the esca-associated fungi Pch, Tmi and Fomitiporia mediterranea (Fme). Calli of both cvs. were grown as dual cultures with Pch, Tmi and Fme. The fungi grew well in the presence of calli of both cvs., but callus growth was reduced. Accumulation and changes of total phenolics and recurring phenolics, and of two phytotoxic pentaketides and pullulans were analyzed by HPLC. On comparing results for cv. Italia and cv. Matilde, it can be seen that concentrations of phenolics are strongly related to the cv. The paper discusses the possible relationship between melanin biosynthesis in Pch and Tmi, which utilize pentaketide metabolites as intermediates and their pathogenicity related to phytotoxity of scytalone and isosclerone. 相似文献
109.
Meningioangiomatosis in a dog: magnetic resonance imaging and neuropathological studies 总被引:1,自引:0,他引:1
A case of a dog with a long-standing history of seizures is reported. Neurological examination suggested an intracranial focal lesion, while magnetic resonance imaging disclosed a right cerebral mass with ventricular involvement. Pathological analysis of the resected specimen revealed characteristics of meningioangiomatosis. 相似文献
110.
M. Macari R. L. Furlan F. P. Gregorut E. R. Secato J. R. Guerreiro 《British poultry science》1993,34(5):1035-1042
1. The effect of endotoxin, interleukin‐1β and prostaglandin on fever response was studied in 80 broilers (Hubbard strain). Endotoxin (E. coli, LPS) was injected iv (1.5 μg/kg) and icv (1.5 μg/bird); interleukin‐1 (human recombinant IL‐1β, 80 pg/bird) and prostaglandin E2 (5 μg/bird) were injected icv. Indomethacin (10 mg/kg, iv) pretreatment was also used before iv endotoxin injection.
2. The results showed that indomethacin was able to block the fever response induced by iv endotoxin injection, and IL‐1β and PGE2 were both effective in producing fever when injected icv. These data suggest a prostaglandin‐mediated fever response by broilers, and also a strong evidence of the involvement of endogenous pyrogen (interleukin‐1) in fever response in birds. 相似文献