全文获取类型
收费全文 | 319篇 |
免费 | 23篇 |
专业分类
林业 | 15篇 |
农学 | 15篇 |
基础科学 | 2篇 |
113篇 | |
综合类 | 12篇 |
农作物 | 20篇 |
水产渔业 | 41篇 |
畜牧兽医 | 90篇 |
园艺 | 4篇 |
植物保护 | 30篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 15篇 |
2020年 | 17篇 |
2019年 | 18篇 |
2018年 | 21篇 |
2017年 | 16篇 |
2016年 | 18篇 |
2015年 | 12篇 |
2014年 | 9篇 |
2013年 | 13篇 |
2012年 | 23篇 |
2011年 | 27篇 |
2010年 | 14篇 |
2009年 | 11篇 |
2008年 | 24篇 |
2007年 | 16篇 |
2006年 | 22篇 |
2005年 | 11篇 |
2004年 | 9篇 |
2003年 | 13篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有342条查询结果,搜索用时 15 毫秒
131.
The complete amino acid sequence of an α-type gliadin from spelt wheat (spelta) has been deduced from the cloned DNA sequence and compared with α-type gliadin sequences from bread wheat. The comparison showed only minor differences in amino acid sequences between the α-type gliadin from bread wheat and the α-type gliadin from spelta. The two sequences had an identity of 98.5%. Larger differences can be found between different α-type gliadin amino acid sequences from common bread wheat. Because all the different classes of gliadins, α, β, γ, and ω, appear to be active in celiac disease, it is reasonably certain that the spelta gliadin is also toxic. We conclude that spelta is not a safe grain for people with celiac disease, contrary to the implications in labeling a bread made from spelta as “an alternative to wheat”. Our conclusions are in accord with spelta and bread wheat being classed taxonomically as subspecies of the same genus and species, Triticum aestivum L. 相似文献
132.
Kim Dong-Wook Silva Renato Rodrigues Kim Ju-Sung Kim Yoonha Kim Hak-Jin Chung Yong Suk 《Journal of Crop Science and Biotechnology》2020,23(1):73-79
Journal of Crop Science and Biotechnology - Nitrogen management is crucial for high yield potential of crops as well as reducing environmental pollution. However, the heterogeneity of nitrogen... 相似文献
133.
Hugo de Oliveira Barbosa Pedro Paulino Borges Renato Bolson Dala‐Corte Patrick Thomaz de Aquino Martins Fabrício Barreto Teresa 《Fisheries Management and Ecology》2019,26(2):119-130
Understanding variability in the composition of aquatic assemblages requires a multiscale perspective, since processes operating at different spatial scales (from regional to local) drive the community assembly. Here, the relative importance of environmental variables on fish species composition in streams of the Brazilian savanna (Cerrado) is assessed and quantified at local and landscape scales. The importance of both local and landscape environmental variables in structuring fish assemblages was supported. Local variables explained a substantially higher amount of variance of fish assemblages than landscape variables. However, the shared explanation indicate that landscape variables had a complementary effect. The streams sampled were mostly headwaters at similar altitudes and with similar watershed sizes, so the sensitivity of the fish assemblages, even to small landscape gradients, is highlighted. Maintaining these important instream habitat characteristics close to natural conditions seems to be essential for conserving stream fish species, and for this, the landscape context should be taken into account. Considering the near‐pristine condition of the streams studied, these findings can be used as a reference for further studies addressing the effects of human modifications on stream fish biodiversity of the Cerrado. 相似文献
134.
We describe the development and distribution of intestinal aminopeptidase M, dipeptidyl aminopeptidase IV, non-specific esterase, alkaline phosphatase and acid phosphatase, using enzyme histochemistry techniques, in the spotted sand bass larvae ( Paralabrax maculatofasciatus ) under culture conditions. All digestive enzymes tested showed a positive reaction from first feeding (day 2) and throughout the study period (day 30). At first feeding, the main enzymatic activity was in the mucosa throughout the intestines. Later, enzymatic activity occurred in the liver, kidney and stomach. All enzymatic activities increased from days 15 to 20, remaining constant until the end of the study. This enzymatic activity suggests the onset of maturation of the digestive tract. After day 20, a positive reaction was recorded in the pyloric caeca for all tested enzymatic activities. Our study confirms the digestive and absorptive functions in the intestines in spotted sand bass larvae from first feeding. It also brings new insight to establish an early weaning strategy during cultivation of spotted sand bass larvae. 相似文献
135.
Jorge Hernández Iker Uriarte María Teresa Viana Renato Westermeier & Ana Farías 《Aquaculture Research》2009,40(15):1694-1702
A feeding experiment was carried out to evaluate two natural diets versus a formulated feed on the performance of weaning red abalone Haliotis rufescens . Four treatment diets were then investigated: a formulated diet; plantlets from culture Macrocystis pyrifera, Porphyra columbina from natural beds; and a mixed diet consisting of a blend of fresh P. columbina together with the formulated diet. This study was performed in a shallow aquaculture system with a horizontal water flow. After 90 days, significant differences were observed between treatments. The highest growth was obtained with Porphyra (3.3 mm month−1 ), followed by the mixed diet (2.6 mm month−1 ), then Macrocystis (2.1 mm month−1 ) and lastly the formulated diet (1.4 mm month−1 ). Moreover, after the diets were tested for stability and remnant nutrients after a 12-h water immersion, a positive trend appeared to be related to the protein/energy (P:E). It is concluded that fronds of P. columbina resulted in the best diet for weaning H. rufescens under horizontal water flow systems, even if apparently the water stability of the formulated diet had a negative impact on abalone performance, particularly due to a poor nutrient retention capacity. Therefore, formulated diets should be improved before being recommended for weaning red abalone. 相似文献
136.
Renato Eiji Kitagima Débora Machado Fracalossi 《Journal of the World Aquaculture Society》2011,42(3):306-312
Apparent digestibility coefficients (ADCs) of amino acids, crude protein, gross energy, and dry matter of canola meal, corn gluten feed, fish offal meal, shrimp and fish offal meal, poultry by‐product meal, and hydrolyzed feather meal were determined for channel catfish, Ictalurus punctatus. Experimental diets contained 30% test ingredient, 69.5% casein‐based reference diet, and 0.5% chromic oxide. Groups of 20 fish (102.45 g) were fed the experimental diets twice a day at 3.5% body weight. Fecal samples were collected in triplicate daily at 0000 h and 0600 h after settlement into collection devices. Shrimp and fish offal meal and corn gluten feed presented significantly lower (P < 0.05) ADC for dry matter (59.5 and 39.3%) suggesting their low value as feedstuffs for catfish feeds. Although ADC values for crude protein were above 80% for all the test ingredients, amino acid digestibility varied significantly, except for histidine whose ADC remained constant regardless of the protein source. Lysine was the first limiting amino acid in most of the test ingredients, except in fish offal meal and poultry by‐product meal. Among the protein sources tested, only fish offal meal and poultry by‐product meal met channel catfish amino acid requirements for a 28% digestible protein grow‐out diet. 相似文献
137.
138.
Cruz Jaqueline Matos Montagnolli Renato Nallin Bidoia Ederio Dino 《Water, air, and soil pollution》2020,231(8):1-16
Water, Air, &; Soil Pollution - Phytoremediation is a cost-effective and relatively cleaner method for remediating contaminated areas using plants. Certain plants, including some sunflower... 相似文献
139.
The environmental variables affecting the spatial distribution of Squatina guggenheim Marini, 1936, an important commercial resource, are unknown. Here the influence of temperature, salinity and depth on the distribution of S. guggenheim in the Southwest Atlantic was analyzed. The species–habitat associations were evaluated for the S. guggenheim population as a whole as well as segregated by sex and by size classes (group 1, 23–44 cm; group 2, 45–74 cm; group 3, 75–91 cm LT). Sampling took place during four bottom trawl surveys conducted in the Argentine–Uruguayan Common Fishing Zone (AUCFZ) during spring (October 1997) and fall (March 1997, March–April 1998, May–June 1998). The sharks were captured using an Engel bottom trawl and the hydrographical information was obtained using a CTD. Bottom depth was measured with an echo-sounder. The distribution of the population was affected (P ≤ 0.05) by temperature during spring and fall, while it was affected by salinity only in spring. S. guggenheim showed preference for temperatures ranging from 7.0 to 18.5 °C and salinity values ranging from 33.4 to 33.8. Generally, the distribution of males was affected (P ≤ 0.05) by temperature during both seasons, while females were influenced by temperature only in spring. The distribution of both sexes was affected by salinity in spring but not in fall. The distribution of adults sharks (group 3) was more affected by temperature and salinity than that of juveniles sharks (groups 1 and 2). Depth had no effects on the distribution of adults (males or females); however, juveniles belonging to size-group 2 were associated with depth during both spring and fall. High population catches were associated to thermal fronts during all surveys suggesting that these oceanographic structures play an important role as feeding areas for S. guggenheim. A population strategy of spatial segregation by size was proposed and discussed. 相似文献