全文获取类型
收费全文 | 435篇 |
免费 | 41篇 |
专业分类
林业 | 24篇 |
农学 | 1篇 |
基础科学 | 2篇 |
114篇 | |
综合类 | 21篇 |
农作物 | 19篇 |
水产渔业 | 26篇 |
畜牧兽医 | 224篇 |
园艺 | 12篇 |
植物保护 | 33篇 |
出版年
2023年 | 8篇 |
2022年 | 9篇 |
2021年 | 16篇 |
2020年 | 21篇 |
2019年 | 17篇 |
2018年 | 26篇 |
2017年 | 24篇 |
2016年 | 21篇 |
2015年 | 10篇 |
2014年 | 21篇 |
2013年 | 36篇 |
2012年 | 29篇 |
2011年 | 41篇 |
2010年 | 24篇 |
2009年 | 17篇 |
2008年 | 24篇 |
2007年 | 37篇 |
2006年 | 21篇 |
2005年 | 25篇 |
2004年 | 17篇 |
2003年 | 11篇 |
2002年 | 11篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1980年 | 2篇 |
排序方式: 共有476条查询结果,搜索用时 46 毫秒
411.
Leptin and adiponectin are adipokines produced by the white adipose tissue. The adipokines have been shown to be valuable quantitative markers of adiposity in dogs. Leptin positively correlates with body condition score (BCS) in dogs, regardless of age, sex and breed, and is influenced by feeding state, pharmacological treatment and thyroid gland activity. Conversely, adiponectin negatively correlates with body fat mass and is therefore more abundant in lean animals. The implication of leptin and adiponectin in the pathogenesis of metabolic syndrome is well established in humans, but currently lacking in dogs. Additional studies are necessary to demonstrate their potential usefulness for monitoring the progression of obesity-related diseases and response to treatment. To date, measurement of canine leptin and adiponectin has been used in experimental studies only, whereas bodyweight and BCS are considered the first-approach parameters for the routine assessment of body fat content in obese dogs. 相似文献
412.
Vitari F Di Giancamillo A Deponti D Carollo V Domeneghini C 《Veterinary research communications》2012,36(1):71-80
Ghrelin is involved in many biological processes, ranging from appetite regulation and the release of growth hormone to the
regulation of gastrointestinal motility and secretion processes. Ghrelin expression is not homogenously distributed throughout
the gastrointestinal tract; expression is species-specific and can also depend on the animal age. This study was performed
to investigate ghrelin immunolocalization in the gastrointestinal tract of pigs at different ages: 1 day (birth), 28 days
(weaning), 2 months, 4 months, and 7 months (pre-puberty). Tissue samples were collected along the entire gastrointestinal
tract and were examined by immunohistochemistry and double-immunofluorescence. Histometry was performed by counting the number
of endocrine ghrelin immunopositive cells in the gastrointestinal mucosa. Ghrelin was found to be present along the swine
alimentary canal from the stomach to the caecum. In all regions of the alimentary canal of the animals studied, ghrelin-immunoreactive
(IR) cells co-localized with chromogranin-A and were therefore identified as endocrine cells. In the gastric fundus, ghrelin-immunoreactivity
was partially detected in co-localization with H-K-adenosine triphosphatase and pepsinogen. Ghrelin-IR endocrine cells were
abundant in the oxyntic mucosa but less present in the small intestine and rare in the large intestine. The cell density of
the ghrelin-IR endocrine cells was lowest in the oxyntic mucosa of 1-day-old pigs. We can conclude that gastric ghrelin expression
is not related merely to age but could also potentially be influenced by food intake. 相似文献
413.
414.
Pérez-Balladares Doménica Castañeda-Terán Michael Granda-Albuja María G. Tejera Eduardo Iturralde Gabriel Granda-Albuja Silvana Jaramillo-Vivanco Tatiana Giampieri Francesca Battino Maurizio Alvarez-Suarez José M. 《Plant foods for human nutrition (Dordrecht, Netherlands)》2019,74(3):350-357
Plant Foods for Human Nutrition - Thirteen fruits, eight legumes and three tubers consumed in the Andean regions of Ecuador were studied to determine their bioactive compounds, organic acids,... 相似文献
415.
416.
Two new phenolic esters 9-trans-p-coumaroyloxy-alpha-terpineol (1) and 7-trans-p-coumaroyloxy-taedol (2), both endowed with free radical scavenger activity and cleroda-3,13 (E)-dien-15,18-diol (3) for which a cis stereochemistry at the decalin junction was found, were isolated from the resinous exudate from Haplopappus taeda upper parts. 相似文献
417.
Barbara Forte Beatrice Malgesini Claudia Piutti Francesca Quartieri Alessandra Scolaro Gianluca Papeo 《Marine drugs》2009,7(4):705-753
In his most celebrated tale “The Picture of Dorian Gray”, Oscar Wilde stated that “those who go beneath the surface do so at their peril”. This sentence could be a prophetical warning for the practitioner who voluntarily challenges himself with trying to synthesize marine sponge-deriving pyrrole-imidazole alkaloids. This now nearly triple-digit membered community has been growing exponentially in the last 20 years, both in terms of new representatives and topological complexity – from simple, achiral oroidin to the breathtaking 12-ring stylissadines A and B, each possessing 16 stereocenters. While the biosynthesis and the role in the sponge economy of most of these alkaloids still lies in the realm of speculations, significant biological activities for some of them have clearly emerged. This review will account for the progress in achieving the total synthesis of the more biologically enticing members of this class of natural products. 相似文献
418.
Grazia Marino Francesca Gaggia Filippo Saiano Bruno Biavati Bruno Marangoni 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(2):195-205
The antimicrobial activity of leaf and callus extracts of Melia azedarach was tested on in vitro shoot cultures of the peach rootstoch ‘MRS 2/5’ (Prunus cerasifera × Prunus spinosa) that were heavily contaminated with Sphingomonas paucimobilis (Sp) and Bacillus circulans (Bc). The extracts were filter-sterilised and added at 0%, 1%, 5%, 10% and 20% to a modified Murashige and Skoog proliferation
medium previously autoclave-sterilised. Up to about 17% shoots died with 10–20% extract, except for Sp-contaminated shoots,
whose survival was reduced to 50% after treatment with 20% extract. No shoots died with 1% to 5% supplement. The undiluted
leaf extract showed bactericidal activity on plated Sp and Bc isolates. The homogenates of shoots randomly collected from
treated cultures were processed for bacterial colony counting. Thus the 10% supplement was the best treatment for ridding
Bc-contaminated cultures of bacteria (although 5% had a similar bactericidal effect), and allowing shoot growth and proliferation
comparable to controls at the fifth subculture on a standard medium, while 20% extract was needed to eliminate Sp, and could
induce higher growth and proliferation rates in surviving shoots than in untreated cultures. Callus extract was ineffective.
The bactericidal activity of the leaf extract seemed attributable to a synergistic effect of azadirachtin with other unidentified
compounds present in the extract. 相似文献
419.
Patrizia Di Filippo Carmela Riccardi Donatella Pomata Claudio Gariazzo Francesca Buiarelli 《Water, air, and soil pollution》2010,211(1-4):231-250
Polycyclic aromatic hydrocarbons (PAHs); their derivatives nitro, and methyl-PAHs; n-alkanes; and organic acids were investigated in the aerosol samples collected during two field campaigns conducted at three sampling stations in an industrialized city in southern Italy. The main sources affecting the atmosphere and its toxicity were investigated by means of the diagnostic ratios of: specific particulate-phase PAHs, marker compounds among nitro-PAHs, alkanes, and acids, the dominant wind direction, daily and seasonal abundance of carcinogenic organic substances. The potential importance of the non-regulated pollutants to assess the air quality was confirmed; in fact the carcinogenic organic compounds showed to have scarce correlation with particulate matter (PM) concentration. An exceptionally high variability of toxic compounds at a daily scale was due to meteorological condition causing periods of extremely high pollution levels. 相似文献
420.
Alvarez-Suarez JM Giampieri F Damiani E Astolfi P Fattorini D Regoli F Quiles JL Battino M 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(1):31-38
Several monofloral Cuban honeys were analyzed to determine their free radical-scavenging activity and from this the total
antioxidant content was estimated. The protective effect against lipid peroxidation in an in vitro model of rat liver homogenates was evaluated and, lastly, the mineral content of the honeys, which can be related to the
maintenance of intracellular oxidative balance, was determined. The scavenging capacities against hydroxyl and superoxide
radicals were determined using the spin-trapping technique and the hypoxanthine/xanthine oxidase assay, respectively. Lipid
peroxidation was evaluated through the production of TBARS and hydroperoxides. All honeys tested showed potential antioxidant
activity with Linen vine displaying the highest scavenging capacity towards the DPPH, hydroxyl and superoxide radicals, while the least efficient
was Christmas vine honey. Honeys also inhibited, in a concentration-dependent mode, lipid peroxidation in rat liver homogenates, with Linen vine resulting the best while the least effective was Christmas vine honey. The ability to scavenge free radicals and protect against lipid peroxidation may contribute to the ability of certain
Cuban honeys to help in preventing/reducing some inflammatory diseases in which oxidative stress is involved. A total of eight
minerals were identified and quantified as follows: cadmium, chromium, copper, nickel, iron, manganese, lead, and zinc. Minerals
found in higher concentrations were iron, zinc and manganese. 相似文献