全文获取类型
收费全文 | 513篇 |
免费 | 51篇 |
专业分类
林业 | 26篇 |
农学 | 11篇 |
基础科学 | 5篇 |
88篇 | |
综合类 | 49篇 |
农作物 | 59篇 |
水产渔业 | 44篇 |
畜牧兽医 | 231篇 |
园艺 | 6篇 |
植物保护 | 45篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 17篇 |
2021年 | 38篇 |
2020年 | 23篇 |
2019年 | 27篇 |
2018年 | 27篇 |
2017年 | 26篇 |
2016年 | 25篇 |
2015年 | 19篇 |
2014年 | 26篇 |
2013年 | 25篇 |
2012年 | 31篇 |
2011年 | 36篇 |
2010年 | 22篇 |
2009年 | 17篇 |
2008年 | 29篇 |
2007年 | 18篇 |
2006年 | 20篇 |
2005年 | 11篇 |
2004年 | 18篇 |
2003年 | 11篇 |
2002年 | 15篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有564条查询结果,搜索用时 921 毫秒
1.
2.
M. A. Gomez J. A. Navarro S. Gomez P. Camara J. C. Gomez A. Bernabé 《Anatomia, histologia, embryologia》1989,18(4):305-315
The structure and ultrastructure of the adenohypophyseal pars distalis in kids of the Murciano-granadiana breed (18 males and 12 females), aged 2-3 months and with an average carcass weight of 8 kg has been studied. Techniques of staining (Tetrachrome Herlant's, and Cleveland-Wolfe) and histochemistry (PAS, PAS-OG and BA-PAS-OG) contrasted with immunolabelling (PAP) have been used. In addition an ultrastructural study has been made and nucleus and cytoplasm, secretory granules, mitochondria and lysosomes have been measured with a semiautomatic image analyzer (IBAS-1). TSH cells are found in sagittal section in the anterior area and in an antero-caudodorsal band, and transversally in the ventral and medial region; they are 6% and their average size is 14.15 microns. Ultrastructurally they are a single cellular type with spherical granules whose size is 195 nm in males and 149 in females; these granules are characterized by a clear halo and a variable electronic density. The rough endoplasmic reticulum is found as slightly enlarged vesicles with a homogeneous and moderately electro-dense content or in concentric stratifications. 相似文献
3.
Single cells were mechanically isolated from leaf-derived callus of mature Juniperus oxycedrus L. These cells divided and gave rise to callus when plated on medium containing growth regulators. Best plating efficiency was obtained on a modified Schenk and Hildebrandt medium supplemented with 0.6 micro M 2,4-dichlorophenoxyacetic acid and 100 mg l(-1) casein hydrolyzate. Although single-cell-derived callus showed poor morphogenic potential, both adventitious shoots and embryogenic tissues differentiated from the callus. We also achieved induction of somatic embryogenesis in leaf explants of mature J. oxycedrus trees cultured in the presence of 6.0 or 10.0 micro M 2,4-dichlorophenoxyacetic acid or picloram. Frequency of embryogenic callus ranged from 6 to 18%; however, under the culture conditions tested, isolated embryos failed to develop into plants. 相似文献
4.
5.
6.
7.
8.
9.
Natalia Siwinska Agnieszka Zak Malwina Slowikowska Artur Niedzwiedz Rafal Ciaputa Izabela Janus Marek Lipiec Lukasz Radulski Adam Szymerowski Marcin Nowak 《Equine Veterinary Education》2023,35(2):e61-e65
Bovine tuberculosis is a contagious and zoonotic disease of animals and humans. In Europe, the number of reported cases of tuberculosis has decreased. Equidae are relatively rarely infected even in endemic areas. The presented report describes a case of chronic Mycobacterium bovis tuberculosis in a 30-year-old female donkey. The donkey initially presented with persistent lymphadenopathy; however, as the disease progressed, weight loss became apparent. To the authors' knowledge, this is the second confirmed case of tuberculosis in a donkey in Europe. 相似文献