全文获取类型
收费全文 | 203篇 |
免费 | 14篇 |
专业分类
林业 | 15篇 |
农学 | 10篇 |
55篇 | |
综合类 | 6篇 |
农作物 | 14篇 |
水产渔业 | 26篇 |
畜牧兽医 | 63篇 |
园艺 | 4篇 |
植物保护 | 24篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 12篇 |
2019年 | 8篇 |
2018年 | 18篇 |
2017年 | 13篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 15篇 |
2011年 | 22篇 |
2010年 | 6篇 |
2009年 | 19篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 1篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有217条查询结果,搜索用时 15 毫秒
41.
Ana Carina Heil da Silva Matos Juliana da Silva Leite Anglica Consalter Marcela Freire Vallim de Mello Maria de Lourdes Gonalves Ferreira Ana Beatriz Monteiro Fosenca Ana Maria Reis Ferreira 《Reproduction in domestic animals》2019,54(6):828-834
Granulosa cell tumour (GCT) is a majorly observed ovarian tumour in female dogs. It is essential to diagnose GCT in its initial phase before any symptoms occur, as histological and physiological differences may be observed based on the evolution of this neoplasia. This study aimed to analyse the anatomic histopathology of GCT in its initial stage, with findings of ovaries not yet with the suspicion of neoplasms in the Canis familiaris. A sample including 55 ovaries presented GCT in 40 female dogs. The histopathological analysis was performed considering the intensity of pleomorphism, vascularization and inflammatory infiltrate. Furthermore, we evaluated the mitoses count in 10 fields using 40× magnification. Out of the 40 animals evaluated, 62.5% (25/40) presented the tumour in only one ovary. The Call‐Exner corpuscle was present in 65% (26/40) of the cases. The follicular histological pattern was present in 52.5% (21/40) of the animals. The presence of the Call‐Exner bodies and the degree of tumour cell pleomorphism (p = 0.033) were associated. Moreover, the degree of vascularization and the intensity of the inflammatory infiltrate were also related (p = 0.001). In addition, there was a positive relationship between the increase in pleomorphism and the mean age of the animals (p = 0.044). This study confirmed that the appearance of this tumour may precede any clinical symptomatology. In this study, the most frequent histopathological pattern was the follicular. The characteristics of the granulosa cell tumour diagnosed early were poorly pleomorphic cells, low mitotic index and presence of Call‐Exner body. 相似文献
42.
43.
44.
45.
Cristina Martínez-Garza Marcela Osorio-BeristainDavid Valenzuela-Galván Alondra Nicolás-Medina 《Forest Ecology and Management》2011,262(12):2207-2218
Domestic livestock grazing and firewood extraction are chronic and pervasive disturbances in dry secondary forest that reduce diversity and modify composition. Exclosure of such disturbances may allow the reestablishment of original diversity. To investigate potential vegetation recovery following 30 years of perturbation, seed rain was evaluated monthly during 3 years in 96 0.78 m2 seed traps located in eight exclosures established in 2006 in a species-poor secondary dry forest in central Mexico. Twelve additional seed traps were located outside the exclosures in 2010 for comparison purposes. Baseline diversity of seed sources (trees, ?5 cm DBH) was recorded to compare standing tree composition with seed rain. Also, baseline diversity of potential primary (birds) and secondary (ants) dispersal vectors were registered to infer current plant-animal interactions. Total seed rain over 3 years within the exclosures comprised 180,375 seeds from 61 woody species, an average of 1.12 seeds/m2/month. Half of these species (31) and 95% of the seeds falling within the exclosures belonged to trees typical of perturbed sites. Sixty percent of all recorded seeds belonged to an early-successional, bird-dispersed shrub (Hamelia patens Jacq., Rubiaceae). Seed rain at one non-excluded plot was dominated by the wind-dispersed early-successional tree Heliocarpus sp. (Tiliaceae). Richness and seed density increased significantly in the second year of exclusion; however, by the third year, richness remained constant while seed density decreased. Seed rain was richer and more abundant during the dry season and was dominated by wind-dispersed species. Phenology, successional status and the dispersal modes of woody species explained most variance in richness and seed density of seed rain in early-successional dry forest. Seeds of early-successional species were dispersed in equal measure by abiotic and biotic vectors, whereas biotic vectors dispersed a higher density of late-successional seeds. The amount and timing of fall of abiotically dispersed seeds of the three most abundant species in the standing tree community may prolong their current domination of the landscape. However, even when richness in the seed rain within exclosures remained constant through time, composition was gradually shifting towards animal-dispersed species which may start a positive feedback producing an increase in animal visitation and a further increase of richness. 相似文献
46.
López-Hurtado M Arteaga-Troncoso G Escobedo-Guerra MR Guerra-Infante FM 《Veterinary immunology and immunopathology》2009,127(1-2):181-185
Endocytic activity of phagocytic cells from armadillos infected with viruses, parasites or bacteria is unknown. This report shows that eosinophils from armadillos infected with microfilaria act against these helmintic parasites but have deficiencies in their oxygen-dependent bacteriocidal mechanisms and also in endocytic capacity against yeast. 相似文献
47.
González-de-la-Vara Mdel R Valdez RA Lemus-Ramirez V Vázquez-Chagoyán JC Villa-Godoy A Romano MC 《Canadian journal of veterinary research》2011,75(3):216-221
Dairy cattle suffer stress from management and production; contemporary farming tries to improve animal welfare and reduce stress. Therefore, the assessment of long-term hypothalamic-pituitary-adrenal function using non-invasive techniques is useful. The aims in this study were: to measure cortisol concentration in cow and calves hair by radioimmunoassay (RIA), to test cortisol accumulation in bovine hair after adrenocorticotropic hormone (ACTH) challenges, and determine the influence of hair color on cortisol concentrations. Fifteen Holstein heifers were allotted to 3 groups (n = 5 each): in control group (C), just the hair was sampled; in the saline solution group (SS), IV saline solution was administered on days 0, 7, and 14; and the ACTH group was challenged 3 times with ACTH (0.15 UI per kg of body weight) on days 0, 7, and 14. Serum samples from the SS and ACTH groups were obtained 0, 60 and 90 min post-injection. Serum cortisol concentration was greater 60 and 90 min after injection with ACTH. Hair was clipped on days 0, 14, 28, and 44. Hair cortisol was methanol extracted and measured by RIA. Hair cortisol was preserved for 11 mo. Hair cortisol concentrations in the ACTH group were greater than in the saline and control groups on days 14 and 28, but not on day 44. Concentrations were greater in calves than in cows and greater in white hair than in black hair. Cortisol accumulated in bovine hair after ACTH challenges, but the concentration was affected by both age and hair color. If hair color effects are taken into account, assessing cortisol concentration in hair is a potentially useful non-invasive method for assessing stress in cattle. 相似文献
48.
Ruiz Maria Luiza Owatari Marco Shizuo Yamashita Marcela Maya Ferrarezi José Victor Saffadi Garcia Patricia Cardoso Lucas Martins Maurício Laterça Mouriño José Luiz Pedreira 《Tropical animal health and production》2020,52(1):167-176
Tropical Animal Health and Production - The aims of this study were to evaluate the inclusion of different concentrations of Lactobacillus plantarum in Nile tilapia diet and to verify histological... 相似文献
49.
This study was conducted to examine the potential for implantation and sustainable fetal development of mouse embryos cultured from the pronuclear to blastocyst stage. Pronuclear embryos from ICR mice (Harlan Sprague‐Dawley) were cultured in Sydney IVF sequential media (Cook) to the blastocyst stage in medium only or co‐cultured with autologous cumulus cells. We also experimented with co‐culture in 100 µL drops. Drop co‐culture produced blastocyst formation rates with a mean of 47.0%, which was significantly higher (P < 0.05) compared to embryos cultured in identical culture conditions except without cumulus cells at 27.3%. Blastocysts obtained in vitro in Cook medium only and co‐cultured in Cook medium with cumulus cells were transferred to pseudopregnant females of ICR strain. The day of blastocyst transfer into surrogate females was designated as post‐transfer of blastocyst day 1 (PT 1). The implantation and fetal development was compared to embryo transfer of in vivo derived blastocysts, which served as controls. There were no statistical differences for implantation and fetal development rates for blastocysts cultured in vitro in either Cook medium only or co‐culture in Cook medium with cumulus cells compared to in vivo‐derived blastocysts. The advantage of the co‐culture system is in generating more blastocysts available for transfer. 相似文献
50.
Premysl Mikula Jana Blahova Marcela Havelkova Martin Hulak 《Pesticide biochemistry and physiology》2009,93(1):13-89
The aim of the study was to evaluate the effect of subchronic exposure to the herbicide LASSO MTX (alachlor 42% W/V) on biometric parameters and important liver biomarkers in the common carp (Cyprinus carpio). One year old fish were exposed for 28 days to LASSO MTX added to the tank water at concentrations of 240 and 2400 μg L−1. The exposure did not affect fish biometric parameters. Glutathione-S-tranferase (GST) activity in liver (hepatopancreas) remained unchanged in exposed fish when compared to controls. However, significant induction of total cytochrome P 450 (CYP 450), ethoxyresorufin-O-deethylase (EROD) activity and elevated glutathione (GSH) in liver of exposed fish were detected. 相似文献