全文获取类型
收费全文 | 179篇 |
免费 | 6篇 |
专业分类
林业 | 13篇 |
农学 | 6篇 |
56篇 | |
综合类 | 2篇 |
农作物 | 19篇 |
水产渔业 | 14篇 |
畜牧兽医 | 69篇 |
园艺 | 1篇 |
植物保护 | 5篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 9篇 |
2019年 | 4篇 |
2018年 | 13篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 9篇 |
2014年 | 15篇 |
2013年 | 13篇 |
2012年 | 20篇 |
2011年 | 5篇 |
2010年 | 6篇 |
2009年 | 8篇 |
2008年 | 19篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 10篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 6篇 |
排序方式: 共有185条查询结果,搜索用时 15 毫秒
21.
Tonin AA Pimentel VC da Silva AS de Azevedo MI Souza VC Wolkmer P Rezer JF Badke MR Leal DB Schetinger MR Monteiro SG Lopes ST 《Research in veterinary science》2012,92(2):197-201
Leptospirosis is a systemic disease of humans and domestic animals, mainly dogs, cattle and swine. The course of human leptospirosis varies from mild to severe fatal forms and the most severe form of human leptospirosis is principally caused by Leptospira interrogans serovar icterohaemorrhagiae (L. icterohaemorrhagiae). The enzyme adenosine deaminase (ADA) plays an important role in the production and differentiation of blood cells. The aim of this study was to evaluate the activity of ADA in serum, erythrocytes and lymphocytes of rats infected with L. icterohaemorrhagiae, as compared with non-infected rats. Twenty-four adult rats, divided into two uniform groups (A and B) were used for the enzymatic assays. The animals in Group B were inoculated intraperitoneally with 2×10(8) leptospires/rat, and the rodents in Group A (control) were not-inoculated. Blood collection was performed on days 5 and 15 post-infection (PI) and the blood used to assess the ADA activity. The infection by L.icterohaemorrhagiae altered erythrocyte count, hemoglobin concentration and hematocrit, causing a decrease in all these parameters on day 15 PI. Lymphocytes decreased significantly on day 15 PI, and ADA activity in serum was inhibited in infected rats on days 5 and 15 PI and its activity in erythrocytes were increased on day 5 PI. On day 5 PI, we found an increase in ADA activity in erythrocytes of infected rats. No correlation was observed between hematocrit and erythrocyte ADA activity on days 5 and 15 PI. The ADA activity was inhibited in rats infected on day 15 PI. A positive correlation (r(2)=60) was also observed between the number of lymphocytes and ADA activity in lymphocytes on day 15 PI (P<0.05). In conclusion, our results showed that the ADA activity is altered in serum, lymphocytes and erythrocytes in experimental infection by L.icterohaemorrhagiae in rats, concomitantly with hematological parameters. 相似文献
22.
23.
Oliveira DM Freitas HS Souza MF Arçari DP Ribeiro ML Carvalho PO Bastos DH 《Journal of agricultural and food chemistry》2008,56(22):10527-10532
Yerba maté (Ilex paraguariensis) is rich in polyphenols, especially chlorogenic acids. Evidence suggests that dietary polyphenols could play a role in glucose absorption and metabolism. The aim of this study was to evaluate the antidiabetic properties of yerba maté extract in alloxan-induced diabetic Wistar rats. Animals (n = 41) were divided in four groups: nondiabetic control (NDC, n = 10), nondiabetic yerba maté (NDY, n = 10), diabetic control (DC, n = 11), and diabetic yerba maté (DY, n = 10). The intervention consisted in the administration of yerba maté extract in a 1 g extract/kg body weight dose for 28 days; controls received saline solution only. There were no significant differences in serum glucose, insulin, and hepatic glucose-6-phosphatase activity between the groups that ingested yerba maté extract (NDY and DY) and the controls (NDC and DC). However, the intestinal SGLT1 gene expression was significantly lower in animals that received yerba maté both in upper (p = 0.007) and middle (p < 0.001) small intestine. These results indicate that bioactive compounds present in yerba maté might be capable of interfering in glucose absorption, by decreasing SGLT1 expression. 相似文献
24.
Guerra L Pereira C Andrade PB Rodrigues MA Ferreres F De Pinho PG Seabra RM Valentão P 《Journal of agricultural and food chemistry》2008,56(17):8184-8194
Targeted metabolite analysis of aqueous extract of Rumex induratus leaves, in terms of phenolic compounds and organic acids, and the study of its antioxidant activity against the DPPH(*) radical, a reactive oxygen species, hypochlorous acid, and a reactive nitrogen species, nitric oxide ((*)NO), were performed. The samples were collected in several locations, spontaneously occurring or from greenhouse culture, at different stages of development and seasons. The phenolic composition was achieved by high-performance liquid chromatography (HPLC)-diode array detection, and four hydroxycinnamic acid derivatives and 10 flavonoid glycosides (C- and O-heterosides) were determined. Organic acids composition was established by HPLC-UV, revealing five compounds. The total amount of phenolic compounds and organic acids were affected by growing conditions and developmental phase. The aqueous extract exhibited a dose-related activity against all tested reactive species. 相似文献
25.
Ferreres F Pereira DM Valentão P Andrade PB Seabra RM Sottomayor M 《Journal of agricultural and food chemistry》2008,56(21):9967-9974
Screening of the phenolic compounds from seeds, stems, leaves and petals of Catharanthus roseus (L.) G. Don (cv. Little Bright Eye) was achieved by HPLC-DAD-ESI-MS/MS. This is the first detailed study of noncolored phenolics in C. roseus, which allowed the characterization of three caffeoylquinic acids and fifteen flavonol glycosides (di- and trisaccharides of kaempferol, quercetin and isorhamnetin). Fifteen compounds are reported for the first time in this species. The scavenging ability of the different plant matrices was assessed against DPPH(*) radical and against reactive oxygen (superoxide radical) and a reactive nitrogen (nitric oxide) species. A concentration-dependent protective effect was observed for seeds and tissues, with petals shown to be the most active. 相似文献
26.
Patrícia Pereira De Lima Cibele Soares Pontes Maria de Fátima Arruda 《Aquaculture Research》2009,41(1):53-60
Management practices on most Brazilian shrimp farms have resulted in high expenses for producers and damage to the environment. Applied ethology could provide information on the pattern of shrimp activity, enabling more efficient feeding frequencies. Behavioural activities of the shrimp Litopenaeus vannamei were recorded during different feeding frequencies. The shrimp were kept in aquariums on a 12:12 h light/dark cycle. They were fed commercial ration three (at 6:00, 12:00 and 18:00 hours), four (at 6:00, 10:00, 14:00 and 18:00 hours) or seven times per day (at 6:00. 8:00, 10:00, 12:00, 14:00, 16:00 and 18:00 hours). We observed animals at 15 min?1 aquarium?1 time periods, recording feeding, substrate exploration, swimming and inactivity. Feeding and exploration were the highest for shrimp fed three times per day, swimming was greatest when animals received four feedings, whereas inactivity was higher for shrimp fed seven times per day. There was greater food ingestion between 12:00 and 14:00 hours for animals fed three and four times per day, whereas swimming was high mainly at 18:00 hours for shrimp fed three and seven times per day. The results indicate higher forage‐related activities (exploration/ingestion) when feed was offered three or four times, suggesting optimization in the pattern of shrimp activities based on these feeding frequencies. 相似文献
27.
Matheus S. Barros Odilon P. Morais Júnior Patrícia G. S. Melo Orlando P. Morais Adriano P. Castro Flávio Breseghello 《Euphytica》2018,214(4):61
A plant breeding program is a long-term investment. Therefore, periodic assessment of the effectiveness of a breeding strategy is essential to maximize genetic gains per unit of time and resource invested. In this work, we assessed the effectiveness of the early-generation testing (EGT) approach used in the upland rice (Oryza sativa L.) breeding program at Embrapa (Brazilian Agricultural Research Corporation), Brazil, estimating the genetic progress achieved for three traits in two distinct phases, spanning 15 years. In the first phase (from 2003 to 2010), it was used the bulk method within F3 progenies with prior testing of F2 crosses, while in the second phase (from 2010 to 2017), it was used the bulk method within F2 progenies. The dataset comprised 70 yield trials, involving 1884 F3:5 progenies (phase I) and 925 F2:4 progenies (phase II) from an elite population, and 10 check cultivars, evaluated for grain yield (GY), plant height (PH) and days to flowering (DTF). For estimating the genetic gain, we adapted a generalized linear regression method to compute bi-segmented linear regression coefficients. Desirable genetic gains were achieved only for GY in both phases of the breeding program, with 78.75 kg ha?1 year?1 (2.68%) in the first phase, and 53.78 kg ha?1 year?1 (1.54%) in the second phase. These results show the effectiveness of EGT, especially via bulk method within F3 progenies with prior testing of F2 crosses, applied to upland rice breeding. Some refinements are discussed in the method to make it more cost-effective and more efficient in achieving genetic gains. 相似文献
28.
Patrícia Pereira Machado Fábio Steiner Alan Mario Zuffo Rafael Alves Machado 《Potato Research》2018,61(2):169-182
The adequate supply of boron (B) and zinc (Zn) can improve the structural integrity and permeability of cell membranes, which is a defence mechanism against fungi infection. A greenhouse experiment was conducted to investigate the effect of the application of B and Zn on plant growth and the incidence and severity of potato early blight, a destructive foliar disease of potato crop caused by Alternaria grandis E.G. Simmons. Potato plants (Solanum tuberosum L. cv. Ágata) were grown in 11-l pots filled with sandy soil, unfertilized or fertilized with 5 mg kg?1 B and 5 mg kg?1 Zn (either alone or in combination). Potato plants were inoculated with isolates of Alternaria grandis at 40 days after planting. Early blight incidence and severity were evaluated visually 7 days after inoculation with A. grandis isolates. Disease incidence ranged from 16 to 41% infected leaves, and was significantly highest in the treatment with the application of B, followed by the control, and lowest with application of Zn and B + Zn. Early blight severity ranged from 2.5 to 25%, and was significantly higher in the unfertilized treatment than in those fertilized with Zn either alone or in combination with B. These findings suggest that Zn plays a critical role in potato tolerance to early blight and should be considered as a preventive measure in the disease management plan, since application of zinc reduced the incidence and severity of potato early blight. However, the physiological basis of this remains unknown. 相似文献
29.
da Cunha Karina Patrícia Vieira do Nascimento Clístenes Williams Araújo 《Water, air, and soil pollution》2009,199(1-4):323-341
Water, Air, & Soil Pollution - The southern sector of the Guadiana River basin (GRB) drains the central-western part of the Iberian Pyrite Belt, an area with many polymetallic sulfide deposits... 相似文献
30.
Federico Ferreres Graciliana Lopes Angel Gil-Izquierdo Paula B. Andrade Carla Sousa Teresa Mouga Patrícia Valent?o 《Marine drugs》2012,10(12):2766-2781
Purified phlorotannin extracts from four brown seaweeds (Cystoseira nodicaulis (Withering) M. Roberts, Cystoseira tamariscifolia (Hudson) Papenfuss, Cystoseira usneoides (Linnaeus) M. Roberts and Fucus spiralis Linnaeus), were characterized by HPLC-DAD-ESI-MSn. Fucophloroethol, fucodiphloroethol, fucotriphloroethol, 7-phloroeckol, phlorofucofuroeckol and bieckol/dieckol were identified. The antioxidant activity and the hyaluronidase (HAase) inhibitory capacity exhibited by the extracts were also assessed. A correlation between the extracts activity and their chemical composition was established. F. spiralis, the species presenting higher molecular weight phlorotannins, generally displayed the strongest lipid peroxidation inhibitory activity (IC50 = 2.32 mg/mL dry weight) and the strongest HAase inhibitory capacity (IC50 = 0.73 mg/mL dry weight). As for superoxide radical scavenging, C. nodicaulis was the most efficient species (IC50 = 0.93 mg/mL dry weight), followed by F. spiralis (IC50 = 1.30 mg/mL dry weight). These results show that purified phlorotannin extracts have potent capabilities for preventing and slowing down the skin aging process, which is mainly associated with free radical damage and with the reduction of hyaluronic acid concentration, characteristic of the process. 相似文献