全文获取类型
收费全文 | 368篇 |
免费 | 22篇 |
专业分类
林业 | 13篇 |
农学 | 6篇 |
基础科学 | 5篇 |
94篇 | |
综合类 | 17篇 |
农作物 | 24篇 |
水产渔业 | 13篇 |
畜牧兽医 | 198篇 |
园艺 | 5篇 |
植物保护 | 15篇 |
出版年
2024年 | 4篇 |
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 13篇 |
2020年 | 18篇 |
2019年 | 16篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 16篇 |
2015年 | 13篇 |
2014年 | 24篇 |
2013年 | 30篇 |
2012年 | 26篇 |
2011年 | 29篇 |
2010年 | 21篇 |
2009年 | 17篇 |
2008年 | 20篇 |
2007年 | 24篇 |
2006年 | 10篇 |
2005年 | 17篇 |
2004年 | 15篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 2篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1978年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1967年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有390条查询结果,搜索用时 15 毫秒
111.
Antioxidant properties of carnosine re-evaluated in a ferrylmyoglobin model system and in cooked pork patties 总被引:1,自引:0,他引:1
Carlsen CU Kröger-Ohlsen M Lund MN Lund-Nielsen T Rønn B Skibsted LH 《Journal of agricultural and food chemistry》2002,50(24):7164-7168
The antioxidative effect of purified carnosine (i.e., separated from the common contaminant hydrazine) has been evaluated in two systems: (i) Carnosine was found to possess poor reducing properties toward the prooxidant ferrylmyoglobin; at pH approximately 5 the presence of carnosine did not increase the rate of reduction of MbFe(IV)=O compared to autoreduction, whereas at pH 7.4 the rate constant for reduction by carnosine was 0.010 +/- 0.002 M(-1).s(-1) (I = 0.16; 25.0 degrees C). (ii) In cooked pork patties prepared from meat (longissimus dorsi and masseter) with purified or nonpurified carnosine added, the effect of purified carnosine was insignificant when compared to control patties, whereas patties with carnosine contaminated with hydrazine had a lower oxidation level than patties with purified carnosine. Carnosine is concluded not to deactivate the prooxidant ferrylmyoglobin and not to have any antioxidative effect in cooked pork. 相似文献
112.
Andersen KE Bjergegaard C Møller P Sørensen JC Sørensen H 《Journal of agricultural and food chemistry》2005,53(14):5809-5817
The contents of raffinose family oligosaccharides (RFO) and sucrose in Brassica, Lupinus, Pisum, and Hordeum species were investigated by chemometric principal component analysis (PCA). Hordeum samples contained sucrose and raffinose, and Brassica samples all contained sucrose, raffinose, and stachyose. In addition to these, the Pisum samples contained verbascose and the Lupinus samples also contained ajugose. High stachyose and low ajugose contents were found in Lupinus albus in contrast to Lupinus angustifolius, having low stachyose and high ajugose contents. Lupinus luteus had average stachyose and ajugose contents, whereas large amounts of verbascose were accumulated in these seeds. Lupinus mutabilis had high stachyose and low ajugose contents, similar to the composition in L. albus but showing higher raffinose content. The Brassica samples also showed compositional RFO variations within the species, and subgroup formations were discovered within the investigated Brassica napus varieties. PCA results indicated compositional variations between the investigated genera and within the various species of value as chemotaxonomic defined parameters and as tools in evaluations of authenticity/falsifications when RFO-containing plants are used as, for example, feed and food additives. 相似文献
113.
Objective: To compare ultrasound‐guided lateral and medial approaches for periarticular injections of the thoracolumbar intervertebral facet joints (IFJ). Study Design: Experimental cadaveric study. Sample Population: Adult equine cadavers (n=4). Methods: IFJ (T12–T13 to L5–L6) were identified by ultrasound (transducer perpendicular to the spine axis) and insertion of a 13 cm, 18 g spinal needle monitored until bone contact using medial (right side) and lateral (left side) approaches. Number of needle insertions at each site, needle repositioning, and insertion depth were recorded. On bone contact 2 mL latex was injected. Intraarticular deposition, distance of latex from the closest articular margin, and presence of latex in the multifidus muscle were established by dissection. Results: Of 96 attempts, only 1 site require reinsertion of the needle; however, 46% of the injections required needle repositioning. Mean ± SD insertion depth was 8.5 ± 1.1 cm. Most injections (86%) were intraarticular and 96% were at or within 0.5 cm of the closest articular margin. Needle insertion relative to the transducer (lateral, medial) had no effect on the distance from the latex to the closest articular margin and all injections were performed into the multifidus muscle. Conclusions: Ultrasound‐guidance facilitated accurate periarticular injection of thoracolumbar IFJ irrespective of using a medial or lateral approach. 相似文献
114.
Campylobacter jejuni is associated with, but not sufficient to cause vibrionic hepatitis in chickens
Jennings JL Sait LC Perrett CA Foster C Williams LK Humphrey TJ Cogan TA 《Veterinary microbiology》2011,149(1-2):193-199
Vibrionic hepatitis is a disease of poultry which is characterised by the presence of focal lesions in the liver, usually 1-2mm in size and greyish-white in colour. The cause of the disease remains unclear, as do the reasons for its recent re-emergence. We examined the livers of commercial broiler chickens taken during processing and found Campylobacter spp. in both normal livers and those displaying signs indicative of focal hepatitis. Livers with signs of hepatitis had significantly more Campylobacter spp. present than those without and other bacterial genera were infrequently present. We were unable to replicate the disease in a healthy host following experimental infection with a Campylobacter jejuni strain isolated from a liver showing signs of focal hepatitis. However, a significant T cell response to C. jejuni was seen in the liver of Campylobacter infected birds. We conclude that the presence of Campylobacter spp. in the liver alone is not sufficient to cause vibrionic hepatitis, but that a predisposing factor, possibly within the host is required. We also provide evidence that chickens mount an adaptive T cell response to systemic C. jejuni. 相似文献
115.
116.
117.
The chemical induced barley mutant m351 was first selected for its low level of mixed-linkage (1–3,1–4) beta-D-glucan (MLG) in an experimental effort to search for barley lines with varied grain MLG contents. The MLG decrease in m351 was associated with increased levels of fructans and crude fiber, but maintained the same plant characteristics under field conditions. The mutation was mapped to a genetic locus flanked by two SSR markers, Bmag369 and Bmag564, on chromosome 7H. Molecular cloning of the CslF6 gene from the m351 line revealed the presence of a point mutation, causing a substitution of an alanine for threonine at position 849 in the amino acid sequence of the corresponding protein. The resultant protein retains some functionality and affects other components in the m351 grain. Those metabolic changes associated with MLG reduction in m351 is the first case reported of a partially functional CslF6 gene in cereal grains. The results contribute to better understanding of the functional effects of the CslF6 gene and the mutant has potential implications in grain end-use quality improvement. 相似文献
118.
Reid EL Worthy CA Probert I Ali ST Love J Napier J Littlechild JA Somerfield PJ Allen MJ 《Marine drugs》2011,9(4):586-602
Emiliania huxleyi is a single celled, marine phytoplankton with global distribution. As a key species for global biogeochemical cycling, a variety of strains have been amassed in various culture collections. Using a library consisting of 52 strains of E. huxleyi and an 'in house' enzyme screening program, we have assessed the functional biodiversity within this species of fundamental importance to global biogeochemical cycling, whilst at the same time determining their potential for exploitation in biocatalytic applications. Here, we describe the screening of E. huxleyi strains, as well as a coccolithovirus infected strain, for commercially relevant biocatalytic enzymes such as acid/alkali phosphodiesterase, acid/alkali phosphomonoesterase, EC1.1.1-type dehydrogenase, EC1.3.1-type dehydrogenase and carboxylesterase. 相似文献
119.
OBJECTIVE: This study was undertaken to establish the prevalence and severity of nutritional problems among low-income children of elementary school age in the Los Angeles Unified School District (LAUSD) in order to collect baseline data to inform policy-makers. DESIGN AND METHODS: A cross-sectional survey of children in 14 elementary schools was conducted from January to June, 1998. Nine hundred and nineteen children were measured and interviewed. The planning, design and data analysis were carried out in collaboration with key LAUSD policy-makers. RESULTS: More than 35% of the sample was classified as being at risk for overweight or overweight according to body mass index. CONCLUSION: There is a high prevalence of children who are at risk for overweight or who are overweight in Los Angeles. This finding has triggered the development of multiple school-based intervention programmes. 相似文献
120.
Salovaara S Larsson Alminger M Eklund-Jonsson C Andlid T Sandberg AS 《Journal of agricultural and food chemistry》2003,51(17):5131-5136
The iron dialyzability and uptake in relation to transit time through the stomach and small intestine was investigated using a dynamic in vitro gastrointestinal model in combination with Caco-2 cells. Three test meals were evaluated, consisting of lactic fermented vegetables with white (I) or whole meal bread (II) and of sourdough-fermented rye bread (III). Three transit times were tested (fast, medium, and slow transport). Iron dialyzability and absorption differed significantly between medium and slow transit time for meal I and between fast and medium transit time for meal III. For meal II, high in phytate, the iron dialyzability and absorption were low irrespective of transit time. The meals could be ranked with respect to iron dialyzability and uptake in the order I > III > II. Although the in vitro models used have limitations compared to in vivo experiments, the results suggest that an increased transit time may improve iron availability. 相似文献