全文获取类型
| 收费全文 | 11548篇 |
| 免费 | 825篇 |
| 国内免费 | 111篇 |
专业分类
| 林业 | 1095篇 |
| 农学 | 485篇 |
| 基础科学 | 96篇 |
| 2980篇 | |
| 综合类 | 486篇 |
| 农作物 | 626篇 |
| 水产渔业 | 1255篇 |
| 畜牧兽医 | 4221篇 |
| 园艺 | 205篇 |
| 植物保护 | 1035篇 |
出版年
| 2024年 | 16篇 |
| 2023年 | 89篇 |
| 2022年 | 153篇 |
| 2021年 | 297篇 |
| 2020年 | 316篇 |
| 2019年 | 296篇 |
| 2018年 | 530篇 |
| 2017年 | 542篇 |
| 2016年 | 544篇 |
| 2015年 | 421篇 |
| 2014年 | 480篇 |
| 2013年 | 743篇 |
| 2012年 | 923篇 |
| 2011年 | 859篇 |
| 2010年 | 545篇 |
| 2009年 | 454篇 |
| 2008年 | 635篇 |
| 2007年 | 645篇 |
| 2006年 | 530篇 |
| 2005年 | 517篇 |
| 2004年 | 439篇 |
| 2003年 | 401篇 |
| 2002年 | 319篇 |
| 2001年 | 231篇 |
| 2000年 | 238篇 |
| 1999年 | 202篇 |
| 1998年 | 52篇 |
| 1997年 | 56篇 |
| 1996年 | 38篇 |
| 1995年 | 37篇 |
| 1994年 | 23篇 |
| 1993年 | 22篇 |
| 1992年 | 60篇 |
| 1991年 | 45篇 |
| 1990年 | 51篇 |
| 1989年 | 53篇 |
| 1988年 | 42篇 |
| 1987年 | 42篇 |
| 1986年 | 48篇 |
| 1985年 | 53篇 |
| 1984年 | 40篇 |
| 1983年 | 37篇 |
| 1982年 | 20篇 |
| 1979年 | 34篇 |
| 1978年 | 32篇 |
| 1977年 | 30篇 |
| 1974年 | 30篇 |
| 1973年 | 45篇 |
| 1972年 | 33篇 |
| 1971年 | 29篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
61.
Josiane C. Panisson Nathália C. Oliveira Cristina M. Sá-Fortes Adsos A. Passos Claudia C. da Silva Wagner A. G. Araújo Idael M. G. Lopes Gleison M. S. Costa Iara Q. Ataíde Bruno A. N. Silva 《Animal Science Journal》2021,92(1):e13592
Improvements in sow productivity have raised questions regarding dietary vitamin D recommendations. The present study aimed to evaluate the effects of the housing system with access to sunlight exposure and supplementation of 25-hydroxicholecalciferol on performance and serum levels of 25(OH)D3 in sows during gestation and lactation. Sows were distributed in an experimental design with two housing systems: gestation crates or gestation free-range system with external area for sunlight exposure; and two diets: 0 or 50 μg of 25-hydroxicholecalciferol kg−1. The use of 25-hydroxicholecalciferol tended (P = 0.052) to improve total born and influenced (P = 0.046) on number of born alive. Litter weight at birth was also increased (P = 0.01) by 25-hydroxicholecalciferol supplementation; 25-hydroxicholecalciferol supplementation and housing system (free-range with sunlight exposure) tended to increase weaning weight (P = 0.07) and litter daily gain (P = 0.051) during lactation. Exposure to sunlight and 25-hydroxicholecalciferol supplementation increased 25(OH)D3 serum levels when compared with control treatment during gestation (136.95 vs. 113.92 ng mL−1; P = 0.035) and lactation (120.29 vs. 88.93 ng mL−1; P = 0.026). In conclusion, the association of 25-hydroxicholecalciferol supplementation with exposure to sunlight during gestation improved significantly 25(OH)D3 serum levels and consequently performance traits in gestation and lactation. 相似文献
62.
David Santiago‐Ramos Juan de Dios Figueroa‐Crdenas Jos Juan Vles‐Medina Rosalía Reynoso‐Camacho Minerva Ramos‐Gmez Marcela Gaytn‐Martínez Eduardo Morales‐Snchez 《Cereal Chemistry》2015,92(5):475-480
The objective of the present work was to study the effect of annealing and concentration of Ca(OH)2 (lime) and calcium salts on the thermal and rheological properties of maize starch during an ecological nixtamalization process. Thermal and rheological properties of maize starch changed during the ecological nixtamalization process because of three main causes: the annealing phenomenon, type of calcium salt, and calcium salt concentration. In all treatments thermal properties (To, Tp, and Tf) of nixtamal starch increased owing to the annealing process, whereas the type of salt or lime increased thermal properties and decreased pasting properties in this order: CaCl2 > CaSO4 > Ca(OH)2 ≈ CaCO3. This behavior was because of the dissociation of each salt or lime in water. Anions (OH−) can penetrate much more easily into the starch granule and start the gelatinization process by rupturing hydrogen bonds. Additionally, amylose‐lipid complexes were formed during the nixtamalization processes, as indicated by an increasing peak at 4.5 Å in X‐ray diffraction patterns. 相似文献
63.
64.
65.
The influence of crossbreeding on collagen solubility and tenderness of Infraspinatus and Semimembranosus muscles of semi‐intensively reared young bulls 
下载免费PDF全文
下载免费PDF全文 Monika Modzelewska‐Kapituła Zenon Nogalski Aleksandra Kwiatkowska 《Animal Science Journal》2016,87(10):1312-1321
The aim of the present study was to investigate the effects of crossbreeding on collagen content and solubility, shear force (WBSF) and the eating quality of Infraspinatus (INF) and Semimembranosus (SM) muscles of young bulls and the relationships between collagen content and solubility, shear force and the eating quality of beef. The experimental material comprised muscles of crossbred young bulls (about 600 days old) of Polish Holstein‐Friesian (PHF) × Limousine (LM) (n = 10), PHF × Charolaise (CH) (n = 9), PHF × Hereford (HER) (n = 9) breeds. The crossbreeding influenced WBSF, aroma and taste, total, water‐soluble, acid‐soluble, total soluble and insoluble collagen content, as well as the acid‐soluble, total soluble and insoluble collagen proportions. WBSF was significantly negatively correlated with sensorial tenderness and water‐soluble collagen content. The eating quality of beef obtained from different crossbreds was similar; however, the meat from PHF × LM and PHF × HER bulls had lower WBSF values than PHF × CH bulls. © 2016 Japanese Society of Animal Science 相似文献
66.
67.
68.
69.