全文获取类型
收费全文 | 275篇 |
免费 | 48篇 |
国内免费 | 1篇 |
专业分类
林业 | 14篇 |
农学 | 11篇 |
23篇 | |
综合类 | 19篇 |
农作物 | 4篇 |
水产渔业 | 28篇 |
畜牧兽医 | 213篇 |
园艺 | 3篇 |
植物保护 | 9篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 24篇 |
2019年 | 16篇 |
2018年 | 19篇 |
2017年 | 17篇 |
2016年 | 26篇 |
2015年 | 15篇 |
2014年 | 21篇 |
2013年 | 16篇 |
2012年 | 14篇 |
2011年 | 21篇 |
2010年 | 10篇 |
2009年 | 13篇 |
2008年 | 5篇 |
2007年 | 10篇 |
2006年 | 11篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 9篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
排序方式: 共有324条查询结果,搜索用时 671 毫秒
61.
A. M. V. Batista A. F. Mustafa G. R. A. Santos F. F. R. de Carvalho J. C. B. Dubeux Jr M. A. Lira S. B. P. Barbosa 《Journal of Agronomy and Crop Science》2003,189(2):123-126
The objective of this study was to determine ruminal degradability of the dry matter (DM) and crude protein (CP) of 10 varieties of spineless cactus (Opuntia spp.) grown in north‐eastern Brazil. Two ruminally fistulated steers were used in a randomized complete block design. Ash, CP, acid detergent fiber, and acid detergent lignin levels ranged from 10.4 to 13.3 %, 6.2–7.7 %, 19.8–24.8 % and 3.4–5.4 %, respectively. Relative to the other cactus varieties, Redonda had the highest (P < 0.05) in situ soluble DM fraction and effective DM degradability. No differences in effective DM degradability were observed between the other cactus varieties. In situ soluble CP fraction ranged from 1.7 % of CP for the 69 IPA/UFRPE variety to 11.1 % of CP for the Gigante variety. Slowly degradable CP fraction and its rate of degradation were similar among the cactus varieties (average 90 % of CP and 9 % h?1, respectively). The cactus variety 69 IP/UFRPE had a lower (P < 0.05) effective ruminal CP degradability (ECPD) than the other varieties, which had a similar ECPD (average 66 % of CP). It was concluded that differences in ruminal degradability exist between cactus varieties, with more variations observed for ruminal DM than for CP degradability. 相似文献
62.
Maciel Laura Priscila Araújo Amaro de Carvalho Francisco Fernando Ramos Batista Ângela Maria Vieira Guim Adriana do Vale Maciel Michel Cardoso Daniel Barros de Lima Júnior Dorgival Morais 《Tropical animal health and production》2019,51(6):1717-1723
Tropical Animal Health and Production - The objective of this study was to evaluate the effect of the substitution of Tifton 85 hay (Cynodon spp.) with spineless cactus (Nopalea cochenillifera) on... 相似文献
63.
dos Santos Alyce Raiana Monteiro Cabral Carla Heloísa Avelino Cabral Carlos Eduardo Avelino de Barros Lívia Vieira de Barros Jackelliny Melo Cabral Welton Batista Dias Milene Rodrigues 《Tropical animal health and production》2019,51(8):2395-2403
Tropical Animal Health and Production - This study evaluated the effect of energy and protein supplementation on the nutritional characteristics, ingestive behavior, and productive performance in... 相似文献
64.
Effects of Growth Hormone on In Situ Culture of Bovine Preantral Follicles are Dose Dependent
下载免费PDF全文
![点击此处可从《Reproduction in domestic animals》网站下载免费的PDF全文](/ch/ext_images/free.gif)
CR Jimenez JL de Azevedo RG Silveira J Penitente‐Filho EL Carrascal‐Triana AM Zolini VR Araújo CAA Torres 《Reproduction in domestic animals》2016,51(4):575-584
The objective of this study was to evaluate different concentrations of growth hormone (GH) on the development of bovine preantral follicles cultured included in the ovarian tissue (in situ) on the rates of morphologically normal, viable, primordial and developing follicles, as well as the oocyte and follicle diameter and ultrastructural analysis. Ovarian fragments collected from cows with no cross‐breeds defined were cultured in situ for 1 and 7 days in minimal essential medium (α‐MEM+) supplemented with different concentrations of recombinant human GH (0, 10, 25, 50 ng/ml). The ovarian fragments non‐cultured (control) and cultured were processed for classic histology, mechanical isolation and electron transmission microscopy (MET). The parameters underwent anova (Tukey′s and Dunnett′s tests) and chi‐square test (χ2). After 7 days of culture, the treatment with 50 ng/ml GH showed no differences with fresh control (p > 0.05) and had greater effectiveness than in the 0, 10 and 25 ng/ml GH concentrations of the morphologically normal follicles. Regarding the primordial follicles, a reduction was observed in the 50 ng/ml GH concentration concomitant with the significant increase in developing follicles, differing from both the fresh control and the other GH concentrations tested. In addition, 50 ng/ml GH showed a larger follicle and oocyte diameter when compared to the other treatments cultured. Similar structures were ultrastructurally observed in the control group, 50 ng/ml GH. Follicles cultured in 10 ng/ml GH showed nuclear invagination, vacuoles and lesioned basal membrane. Hence, it is concluded that 50 ng/ml GH is the most effective concentration for the development of preantral follicles cultured in situ. 相似文献
65.
Influence of different anaesthetic protocols over the sperm quality on the fresh,chilled (4°C) and frozen‐thawed epididymal sperm samples in domestic dogs
下载免费PDF全文
![点击此处可从《Reproduction in domestic animals》网站下载免费的PDF全文](/ch/ext_images/free.gif)
This study assessed the influence of three different anaesthetic protocols on semen quality obtained from the epididymis. Sixty male dogs undergoing to routine sterilization were assigned to three anaesthetic protocols: thiopental group (TG, n = 20), propofol group (PG, n = 20) and ketamine–dexmedetomidine group (KDG, n = 20). Immediately after orchidectomy, the cauda epididymides and vas deferent ducts were isolated and then a retrograde flushing was performed to collect spermatozoa. In experiment 1, after the initial evaluation of the semen (sperm concentration, sperm motility and the percentages of live spermatozoa, abnormal spermatozoa and acrosome membrane integrity), semen samples were diluted in Tris‐glucose‐egg yolk extender and chilled for 48 hr, and the sperm motility was assessed at 6, 24 and 48 hr. In experiment 2, semen samples were diluted in Tris‐glucose‐egg yolk extender and chilled for 24 hr, and then samples were frozen in two extenders with different glycerol concentrations, to reach a final concentration of 50–100 × 106 spermatozoa ml?1, 20% egg yolk, 0.5% Equex and 4% and 5% glycerol, respectively. Mean values of total sperm concentration, sperm viability and the percentages of intact acrosome and abnormal spermatozoa were not significantly different between experimental groups, and therefore, the anaesthetic protocols assessed did not affect sperm parameters mentioned above. However, our study confirmed a detrimental effect of the use of thiopental (TG) over the total sperm motility (p < 0.05) and progressive sperm motility (p < 0.05) of the fresh and chilled epididymal sperm samples. The anaesthetic protocols including the application of propofol or ketamine–dexmedetomidine can be used to recover sperm in domestic canids without significant changes in sperm quality compared when semen is collected routinely and these techniques could be applicable to endangered wild canids. 相似文献
66.
Anthony R Palmer Igshaan Samuels Clement Cupido Andiswa Finca W Fransiska Kangombe Isa AM Yunusa 《African Journal of Range and Forage Science》2016,33(1):43-51
Following a field campaign to determine the species composition, canopy cover, aboveground annual production and leaf area index (LAI) of the semi-arid savanna of north-western Namibia, we present a production model that can be used by graziers to determine the livestock carrying capacity. The model predicts the annual aboveground net primary production (ANPP) from regression equations of canopy cover by annual production fraction for plant functional classes. We tested the output of the model against another fully independent net primary production (NPP) model, namely the MODIS NPP product. The mean MODIS NPP for the 29 sites was 343 ± 22?kg dry matter (DM) ha?1 y?1 as opposed to 285 ± 142?kg DM ha?1 y?1 for the fAP model that used the regression method (p < 0.01). As a proof of concept, these landscape-scale ANPP values are used to calculate a recommended livestock carrying capacity for the Ehirovipuka Communal Conservancy, a 1 980 km2 communal area with both wildlife and livestock populations. In addition, we also provide details of a field method for predicting landscape-scale LAI from line transect data. This approach can be used to ground reference the LAI values generated from the MODIS LAI product. 相似文献
67.
68.
69.
Alana Batista dos Santos Mara Lúcia Albuquerque Pereira Herymá Giovane de Oliveira Silva Gleidson Giordano Pinto de Carvalho Leandro Sampaio Oliveira Ribeiro Taiala Cristina de Jesus Pereira José Augusto Gomes Azevêdo Larisse Borges Sousa LeandroBorges Sousa Paulo José Presídio Almeida 《Tropical animal health and production》2016,48(7):1491-1495
70.