全文获取类型
收费全文 | 434篇 |
免费 | 35篇 |
专业分类
林业 | 17篇 |
农学 | 27篇 |
基础科学 | 1篇 |
70篇 | |
综合类 | 23篇 |
农作物 | 29篇 |
水产渔业 | 66篇 |
畜牧兽医 | 205篇 |
园艺 | 10篇 |
植物保护 | 21篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 18篇 |
2020年 | 22篇 |
2019年 | 30篇 |
2018年 | 22篇 |
2017年 | 18篇 |
2016年 | 23篇 |
2015年 | 9篇 |
2014年 | 26篇 |
2013年 | 20篇 |
2012年 | 32篇 |
2011年 | 29篇 |
2010年 | 23篇 |
2009年 | 21篇 |
2008年 | 19篇 |
2007年 | 21篇 |
2006年 | 18篇 |
2005年 | 5篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 11篇 |
1997年 | 3篇 |
1996年 | 9篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1969年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有469条查询结果,搜索用时 0 毫秒
51.
52.
TM Sipriani F Grandi LCG da Silva PC Maiorka CI Vannucchi 《Reproduction in domestic animals》2009,44(S2):137-140
Development of the foetal respiratory system includes both pulmonary growth and maturation. In human medicine, a higher incidence of respiratory distress is reported in newborn males. This study aimed to identify different phases of canine foetal lung maturation throughout pregnancy, to determine the stage of pregnancy in which surfactant production begins and to compare pulmonary development of male and female foetuses. Pregnant bitches (34) were subjected to elective ovariohysterectomy and allocated into four groups, according to the stage of pregnancy: 30–40 days of pregnancy (n = 10), 41–50 days (n = 10), 51–60 days (n = 10) and bitches in the first stage of parturition (n = 4). Foetal lungs were histologically processed and evaluated by optical microscopy. The pseudoglandular phase was identified between the 35th day and 46th day of gestation; the onset of canalicular and saccular periods was observed, respectively, from the 48th day and 60th day of pregnancy. Lungs from foetuses at term were in the saccular phase; thus, the development into the alveolar period occurs in the neonatal period. The histological analyses revealed that respiratory tract development is centrifugal, from upper to lower airways. Therefore, it is possible to identify distinct development periods in different portions of the same organ. In conclusion, the saccular phase of lung development begins around 57 and 60 days of pregnancy, the period in which surfactant production is believed to occur. Male and female foetuses present similar pulmonary development from early pregnancy until parturition. 相似文献
53.
Mastrodi Salgado J Baroni Ferreira TR de Oliveira Biazotto F Dos Santos Dias CT 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(1):39-43
Antioxidants are compounds responsible for free radical scavenging in the body. They protect the organism from oxidative modification
of cells and tissues. These modifications have been associated with degenerative diseases, atherosclerosis and carcinogenesis.
Punica granatum displays high antioxidant potential due to the presence of phenolic compounds, which are capable of disease prevention. The
present study showed the highest antioxidant activity in pomegranate peel than in seeds and pulp. Based on these results,
pomegranate peel was used to produce dried extract that was added to commercial tomato juice and orange juice with strawberries.
Analysis to determine the content of phenolic compounds and antioxidant activity was performed on pomegranate pulp, seeds
and peel and in juices enriched with dried extract of pomegranate peel. The dried extract was responsible for a significant
increase in antioxidant activity of the juices, proportional to the concentrations added. However, although both flavors of
enriched juices displayed high antioxidant levels, the samples with higher dried extract concentrations received the lowest
scores from sensory analysis participants due to the characteristic astringent flavor of pomegranate peels. Therefore, to
obtain greater acceptance in the consumer market, we concluded that the maximum addition of dried pomegranate peel extract
is 0.5% in tomato juice and orange juice with strawberries. 相似文献
54.
The protective effect of dietary L-carnitine supplementation was accessed in turbot (Scophthalmusmaximus) challenged with Streptococcus parauberis. Infected fish fed 240mg L-carnitine showed significantly (P < 0.01) higher survival (78%) than infected fish fed 40mg L-carnitine (11%). When dietary L-carnitine supplementation was suspended, a significant increase in mortality was observed in infected fish. The present report documents that dietary L-carnitine fed on a continuous basis may act as an immunostimulant in turbot. 相似文献
55.
Vanessa Dias Capriles Eveline Lopes Almeida Reinaldo Eduardo Ferreira Jos Alfredo Gomes Arêas Caroline Joy Steel Yoon Kil Chang 《Cereal Chemistry》2008,85(5):614-618
The sum of wheat flour and corn starch was replaced by 10, 20, or 30% whole amaranth flour in both conventional (C) and reduced fat (RF) pound cakes, and the effects on physical and sensory properties of the cakes were investigated. RF presented 33% fat reduction. The increasing amaranth levels darkened crust and crumb of cakes, which decreased color acceptability. Fresh amaranth‐containing cakes had similar texture characteristics to the controls, evaluated both instrumentally and sensorially. Sensory evaluation revealed that replacement by 30% amaranth flour decreased C cakes overall acceptability scores, due to its lower specific volume and darker color. Amaranth flour levels had no significant effect on overall acceptability of RF cakes. Hence, the sum of wheat flour and corn starch could be successfully replaced by up to 20% amaranth flour in C and up to 30% in RF pound cakes without negatively affecting sensory quality in fresh cakes. Moisture losses for all the cakes were similar, ≈1% per day during storage. After six days of storage, both C and RF amaranth‐containing cakes had higher hardness and chewiness values than control cakes. Further experiments involving sensory evaluation during storage are necessary to determine the exact limit of amaranth flour replacement. 相似文献
56.
57.
58.
Samuel Luiz Fioreze João Paulo Costa Carneiro Daniela Dias Pinto João Domingos Rodrigues 《Journal of plant nutrition》2017,40(18):2602-2610
We characterized the pollination and fecundation times in soybean flowers and evaluated the effects of kinetin and calcium applications on physiological and productive traits of soybean plants during the reproductive stage. The anatomical study of flowers of eight soybean cultivars showed that fecundation occurred in closed flowers with visible petals, which presented embryo in the first cell divisions. These results indicate that fertilizers and growth regulation applications should be performed before flower opening, which is different from the current recommendation. Foliar applications of kinetin and calcium between the floral bud and full flowering stages did not affect carbon dioxide (CO2) assimilation, yield components and final yield. The results obtained in this research showed the lack of viability of foliar application of calcium and kinetin in order to increase pod set and number of seeds per plant in soybean crop. 相似文献
59.
Glaydson S. dos Reis Matthew A. Adebayo Carlos H. Sampaio Eder C. Lima Pascal S. Thue Irineu A. S. de Brum Silvio L. P. Dias Flavio A. Pavan 《Water, air, and soil pollution》2017,228(1):33
Sludge-derived activated carbons (ACs) were prepared by conventional heating and microwave pyrolysis. The ACs were characterized using several analytical and functional techniques and used for removal of six phenolic compounds from aqueous solutions. The adsorbents exhibited similar features and possessed hydrophobic surfaces. The ACs were assigned mesoporous materials, with specific surface areas of up to 641 and 540 m2 g?1 for CAC-500 and MAC-980, respectively. The preliminary results indicated that phenol removal onto the ACs increased in the order: m-cresol?<?phenol?<?o-cresol?<?2-chrorophenol?<?2-nitrophenol?<?hydroquinone. Hydroquinone exhibited the highest adsorption capacity and was chosen to continue the remaining part of the experimental work—kinetic and isothermal studies. The adsorption kinetic and isotherm data were well described by the Avrami fractionary order and Redlich–Peterson models, respectively. The maximum amounts (Q max) of hydroquinone adsorbed at 25 °C were too high, reaching 1218.3 and 1202.1 mg g?1 for CAC-500 and MAC-980, respectively. The mechanism of adsorption was proposed in this work, and it was suggested that donor–acceptor complex and π–π interactions play major roles in the adsorption process. The adsorbents were also tested on simulated effluents. The two ACs displayed good efficiency for the treatment of industrial simulated effluents. 相似文献
60.
Amanda B. Dias Carmen M.O. MüllerFábio D.S. Larotonda João B. Laurindo 《Journal of Cereal Science》2010
Rice flour is a starchy material with low-cost, because it can be produced from rice that is broken during processing. The aim of this study was to develop biodegradable films based on rice starch and rice flour, and to characterize their physicochemical, microscopic and mechanical properties. Films from rice starch and rice flour were prepared by casting, with glycerol or sorbitol as plasticizer. SEM analysis of starch and flour films revealed compact structures. Rice flour films prepared in the present work have similar mechanical properties to those of starch based films. However, their water vapor permeabilities are two times higher than those of starch based films. Films with sorbitol were less permeable to water and more rigid, while films with glycerol are more plasticized and have poorer water vapor barrier properties. Therefore, preparing edible films from rice flour is a new alternative for using this raw material, which is sometimes much cheaper than commercial starches. 相似文献