全文获取类型
收费全文 | 6297篇 |
免费 | 481篇 |
国内免费 | 2篇 |
专业分类
林业 | 521篇 |
农学 | 185篇 |
基础科学 | 28篇 |
1078篇 | |
综合类 | 724篇 |
农作物 | 315篇 |
水产渔业 | 709篇 |
畜牧兽医 | 2542篇 |
园艺 | 179篇 |
植物保护 | 499篇 |
出版年
2024年 | 7篇 |
2023年 | 61篇 |
2022年 | 138篇 |
2021年 | 229篇 |
2020年 | 278篇 |
2019年 | 321篇 |
2018年 | 312篇 |
2017年 | 276篇 |
2016年 | 256篇 |
2015年 | 184篇 |
2014年 | 255篇 |
2013年 | 363篇 |
2012年 | 454篇 |
2011年 | 512篇 |
2010年 | 261篇 |
2009年 | 258篇 |
2008年 | 377篇 |
2007年 | 370篇 |
2006年 | 298篇 |
2005年 | 256篇 |
2004年 | 236篇 |
2003年 | 247篇 |
2002年 | 187篇 |
2001年 | 69篇 |
2000年 | 54篇 |
1999年 | 57篇 |
1998年 | 41篇 |
1997年 | 26篇 |
1996年 | 30篇 |
1995年 | 21篇 |
1994年 | 23篇 |
1993年 | 12篇 |
1992年 | 24篇 |
1991年 | 24篇 |
1990年 | 22篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 7篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 20篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1978年 | 7篇 |
1976年 | 8篇 |
1974年 | 7篇 |
1971年 | 7篇 |
1924年 | 6篇 |
排序方式: 共有6780条查询结果,搜索用时 78 毫秒
61.
Buckwheat is a pseudocereal that has gained increasing interest of industry and consumers over the past decade. Little, however, is known about its dietary fiber composition and nonstarch polysaccharide structures. Analysis of the monosaccharide composition indicated large amounts of pectic polysaccharides in both insoluble and soluble fiber from buckwheat. Methylation analysis gave further insights into the structures of the polysaccharides. The corresponding partially methylated alditol acetates suggested only low amounts of galactans. Xyloglucans were the main hemicellulosic polysaccharides in the insoluble fiber fraction. Highly branched arabinans, exclusively substituted at position O3, were of higher abundance. These results were confirmed by screening endo‐arabinanase and endo‐galactanase liberated oligosaccharides with high‐performance anion‐exchange chromatography with pulsed amperometric detection and LC‐MS2. Application of this method also demonstrated highly branched arabinan areas within the pectic polysaccharides. Only low amounts of fiber associated hydroxycinnamic acids and diferulic acids were liberated by alkaline treatment, and no evidence was found for their attachment to polysaccharides, suggesting only a minor impact of these structural elements on fiber structures in dehulled buckwheat seeds. 相似文献
62.
Thromboelastographic assessment of the contribution of platelets and clotting proteases to the hypercoagulable state of dogs with immune‐mediated hemolytic anemia
下载免费PDF全文
![点击此处可从《Journal of Veterinary Emergency and Critical Care》网站下载免费的PDF全文](/ch/ext_images/free.gif)
63.
Development and characterization of a technique for percutaneous radiologic gastrojejunostomy tube placement in the dog
下载免费PDF全文
![点击此处可从《Journal of Veterinary Emergency and Critical Care》网站下载免费的PDF全文](/ch/ext_images/free.gif)
64.
65.
66.
Daniel J. Joffe Roxana Lelewski J. Scott Weese Jamie Mcgill-Worsley Catharine Shankel Sonia Mendonca Tara Sager Michael Smith Zvonimir Poljak 《The Canadian veterinary journal. La revue veterinaire canadienne》2016,57(1):46-51
This study investigated the association between presence of respiratory pathogens and development of Canine Infectious Respiratory Disease Complex (CIRDC) in dogs in 5 Canadian small animal clinics. In total, 86 dogs were tested using a commercial PCR respiratory panel; 64 dogs were considered as cases and 22 were control dogs matched by veterinary clinic. No control animals (0/22) were positive for canine parainfluenza virus (CPIV), whereas 27/64 (42%) CIRDC cases were positive. Furthermore, 81% of case dogs tested positive for Mycoplasma cynos, compared with 73% of control dogs. Canine respiratory corona virus (CRCoV) was detected in no control dogs compared with 9.4% of clinical dogs. No animals were positive for any influenza virus type A present in the diagnostic panel. Presence of CPIV was associated (P < 0.01) with the occurrence of CIRDC after adjustment for demographic factors and presence of CRCoV (P = 0.09). 相似文献
67.
68.
Alana Batista dos Santos Mara Lúcia Albuquerque Pereira Herymá Giovane de Oliveira Silva Gleidson Giordano Pinto de Carvalho Taiala Cristina de Jesus Pereira Leandro Sampaio Oliveira Ribeiro José Augusto Gomes Azevêdo Maria das Graças Conceição Parada Costa Silva Larisse Borges Sousa Leandro Borges Sousa Daiane de Oliveira Alencar 《Tropical animal health and production》2016,48(3):509-515
69.
70.
Use of Non‐invasive Methods for Evaluating the Testicular Biometry in Collared Peccaries (Pecari tajacu Linnaeus, 1758)
下载免费PDF全文
![点击此处可从《Anatomia, histologia, embryologia》网站下载免费的PDF全文](/ch/ext_images/free.gif)
G. C. X. Peixoto M. A. Silva G. L. Lima L. B. Campos A. L. C. Paiva V. V. Paula A. R. F. Ricarte A. R. Silva 《Anatomia, histologia, embryologia》2016,45(1):60-66
The aim of this study was to compare the accuracy of two methods used to estimate testicular volume in the collared peccary. Calliper and ultrasonographic measurements of testicular dimensions (length, width and height) of both testes were taken on five adult collared peccaries. The testicular volume was calculated by Lambert's empiric formula: length (L) × width (W) × height (H) × 0.71, the formula of an ellipsoid L × W × H × 0.52, and Hansen's formula: L × W2 × 0.52. The calculated volumes were then compared with the actual ones, which were estimated by water displacement. The mean of true testicular volume was 22.65 ± 1.52 ml. Lambert's formula estimated testicular volume more accurately when ultrasound measurements were taken. However, when the calliper was the methodology used, the results were closest to the true volume, especially when Ellipsoid formula and Hansen's formula were applied, and underestimated the true volumes by 1.53 ± 1.75 ml and 1.53 ± 1.65 ml, respectively. This specific application of technologies in wild animals has the potential to revolutionize the selection process for the collared peccary entering artificial insemination or natural breeding programmes. 相似文献