全文获取类型
收费全文 | 601篇 |
免费 | 77篇 |
国内免费 | 1篇 |
专业分类
林业 | 39篇 |
农学 | 20篇 |
108篇 | |
综合类 | 19篇 |
农作物 | 39篇 |
水产渔业 | 74篇 |
畜牧兽医 | 304篇 |
园艺 | 12篇 |
植物保护 | 64篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 26篇 |
2021年 | 33篇 |
2020年 | 47篇 |
2019年 | 52篇 |
2018年 | 42篇 |
2017年 | 46篇 |
2016年 | 51篇 |
2015年 | 21篇 |
2014年 | 37篇 |
2013年 | 34篇 |
2012年 | 39篇 |
2011年 | 44篇 |
2010年 | 29篇 |
2009年 | 19篇 |
2008年 | 30篇 |
2007年 | 25篇 |
2006年 | 17篇 |
2005年 | 11篇 |
2004年 | 14篇 |
2003年 | 11篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有679条查询结果,搜索用时 15 毫秒
171.
Alexandre Lima NEPOMUCENO Renata FUGANTI-PAGLIARINI Maria Sueli Soares FELIPE Hugo Bruno Correa MOLINARI Edivaldo Domingues VELINI Eduardo Romano de Campos PINTO Maria Lucia Zaidan DAGLI Galdino ANDRADE FILHO Patr cia Machado Bueno FERNANDES 《农业科学与工程前沿(英文版)》2020,7(2):204-210
Globally, the area of land cultivated with genetically modified (GM) crops has increased a thousand-fold over the last two decades. Although this technology has become important for food production, the regulatory frameworks that underpin these outcomes are based on a list of requirements for a risk assessment that differ from country to country. In recent years, policymakers have had the opportunity to learn from the controversies over transgenics to create effective regulatory milestones for emerging technologies, allowing them to reach their potential for a more sustainable agriculture, ensuring food security. In Brazil, Law No. 11.105 of 24 March 2005 established a framework with four main organizations responsible for risk assessment and management. However, most of new breeding technologies did not exist at that time and were not considered in this law. In 2016, Normative Resolution No. 16 of the National Biosafety Technical Commission (CTNBio) was established to address this gap based on the evaluation of the products obtained through these techniques (termed Innovative Precision Improvement Techniques in the resolution), in a case-by-case consultation system. Briefly, if the product is designated to be a GM, the developer will have to go through the biosafety requirements and will be approved only after CTNBio risk assessment. If the product is designated not to be GM (for the purposes of the legislation), then it can be registered using the existing procedures. Currently, 152 GM products are commercially approved in Brazil. In 2018, CTNBio assessed the first consultation on commercial release of plants generated using the new breeding technologies and has subsequently approved six products. It is expected that many institutions would be able to participate in Brazilian and world markets, developing and introducing new biotechnological solutions and products through a more sustainable approach and without facing public disapproval, a common issue for GM crops. 相似文献
172.
Taida Juliana Adorian Patrícia Inês Mombach Dirleise Pianesso Joziane Lima Thaís Soares Luiza Loebens Leila Picolli da Silva 《Aquaculture Nutrition》2020,26(5):1647-1656
This study was conducted with the objective of evaluating the combination of different ratios of soluble and insoluble linseed fibre for silver catfish (Rhamdia quelen). For this, the soluble and insoluble fractions were concentrated separately and combined in four ratios (1:0.5, 1:1, 1:2, 1:4), which were added to silver catfish diets and evaluated in a bioassay. After 45 days of receiving the experimental diets, the animals were submitted to biometry to collect data and tissues. The experimental design was completely randomized, with five treatments and four replications and the means were compared by Tukey's test (p < .05). Diets 1:2 and 1:4 provided higher weight gain, specific growth rate and crude protein deposition to the fish, whereas only the 1:4 diet reflected higher crude body protein. The 1:0.5 diet altered the trypsin activity in the intestine, and, together with the 1:4 diet, it provided a higher intestinal villi height. Body yield, somatic and digestive parameters, chymotrypsin activity and glucose, glycogen and liver protein were not altered, regardless of the experimental diets. In conclusion, the results indicate that linseed fibre acts effectively as a growth promoter in silver catfish diets, with the use of 1:2 and 1:4 ratios optimizing its prebiotic action. 相似文献
173.
Thiago H Napoleo Lidiane P Albuquerque Nataly DL Santos Isabella CV Nova Thmarah A Lima Patrícia MG Paiva Emmanuel V Pontual 《Pest management science》2019,75(5):1212-1222
The midgut of insects is involved in digestion, osmoregulation and immunity. Although several defensive strategies are present in this organ, its organization and function may be disturbed by some insecticidal agents, including bioactive proteins like lectins and protease inhibitors (PIs) from plants. PIs interfere with digestion, leading to poor nutrient absorption and decreasing amino acid bioavailability. Intake of PIs can delay development, cause deformities and reduce fertility. Ingestion of PIs may lead to changes in the set of proteases secreted in the insect gut, but this response is often insufficient and results in aggravation of the malnutrition status. Lectins are proteins that are able to interact with glycoconjugates, including those linked to cell surfaces. Their effects on the midgut include disruption of the peritrophic matrix, brush border and secretory cell layer; induction of apoptosis and oxidative stress; interference with nutrient absorption and transport proteins; and damaging effects on symbionts. In addition, lectins can cross the intestinal barrier and reach the hemolymph. The establishment of resistant insect populations due to selective pressure resulting from massive use of a bioactive protein is an actual possibility, but this can be minimized by the multiple mode‐of‐action of these proteins, mainly the lectins. © 2018 Society of Chemical Industry 相似文献
174.
175.
Susmara Silva Campos Ugo Lima Silva Maria Zita Tabosa Lúcio Eudes de Souza Correia 《Aquaculture International》2009,17(2):113-124
The aim of this study was to analyze the influence of organic fertilizer on the availability of natural food (plankton and
benthos) and water quality. Two fertilization protocols were adopted using inorganic and organic fertilizers with shrimp (stocked
treatment) and their controls (unstocked treatment). Experimental units consisted of 12 circular fiberglass tanks (500 l)
with estuarine sediment, individual aeration and no water exchange. In stocked treatments were used 40 juveniles/m2, and they were fed with 35% crude protein marine shrimp ration, three times a day. Under the organic fertilization protocol,
the plankton showed higher abundance of Nitzschia and rotifers, the phytobenthos consisted mainly of Nitzschia, Amphiprora and Oscillatoria, the epibenthos was represented mainly by nematodes and rotifers, and the macro-invertebrates were mainly oligochaetes. In
relation to inorganic fertilization, the plankton was represented mainly by Coscinodiscus and rotifers, the phytobenthos consisted mainly of Amphiprora and Oscillatoria, the epibenthos was represented mainly by nematodes and rotifers, and the macro-invertebrates were mainly oligochaetes. Dissolved
oxygen was higher for organic fertilizer (6.16 ± 0.98 mg/l) than for inorganic (5.92 ± 1.19 mg/l) while the other water quality
parameters did not present significant differences. Survival was similar in the two fertilization regimes (96.6%). Final body
weight was 11.89 ± 1.73 g for the inorganic fertilizers and 12.28 ± 1.71 g for organic fertilizer. It is concluded that wheat
bran showed good performance in the water quality without exchange, in the availability of natural food, and in the growth
and survival of the shrimps in the microcosms. 相似文献
176.
177.
Fátima Carvalho Paula Lima Fernando Gonçalves Fernanda Russell-Pinto Jorge Machado 《Journal of the World Aquaculture Society》2004,35(2):189-198
Selenastrum, Chlorella and the Cyanophyta groups, important components of the phytoplankton in the natural habitat of Anodonta cygnea in Mira Lagoon, were used separately as experimental diet for Anodonta cygnea. To assess the effects of the different diets, several organic and inorganic compounds of the haemolymph and extrapallial fluid were measured. Protein content was significantly reduced with experimental Non Feed, and carbohydrate content with Non Feed, Selenastrum, Chlorella , and Cyanophyta diets compared to the control in the lagoon. Lipid contents in body fluids were similar among the different diet groups, with the exception of the Chlorella diet, which showed a higher value. In all diets, the inorganic elements, magnesium and chloride, presented a non-significant variation profile. The concentration of sodium and potassium was significantly affected in Selenastrum and Chlorella diets, observing in the Non Feed diet a minimum value for potassium. The non-significant variation of osmolality suggests the presence of a specific osmotic regulatory mechanism independent of the diet. A particular regulation mechanism seems to exist for both calcium and manganese ion inducing similar profiles for all experimental diets with higher contents in Selenastrum and Cyanophyta diets, respectively. The higher calcium ion concentration appears associated with lower protein-carbohydrate contents, probably due to weak calcium aggregation and deposition mechanism, except for the control and Mixture diets. In general, the concentrations of organic and inorganic compounds in the body fluids of Mixture-fed A. cygnea , were more similar to those found in the control diet group. This suggests that an equal mixture of the three algae, Selenastrum, Chlorella , and Cyanophyta, is more appropriate diet to provide the necessary nutrients for a normal maintenance of A. cygnea in the wild. 相似文献
178.
179.
180.
Carrasco L Lima JS Halfen DC Salguero FJ Sánchez-Cordon P Becker G 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2001,48(7):551-554
This report describes a case of fatal aspergillosis caused by A. fumigatus during the recovery of an oiled Magallanic penguin. The possible role of aspergillosis as a possible complication responsible for the mortality of penguins surviving the first days of treatment for oil is emphasized. 相似文献