全文获取类型
收费全文 | 300篇 |
免费 | 17篇 |
专业分类
林业 | 22篇 |
农学 | 6篇 |
38篇 | |
综合类 | 8篇 |
农作物 | 13篇 |
水产渔业 | 20篇 |
畜牧兽医 | 179篇 |
园艺 | 4篇 |
植物保护 | 27篇 |
出版年
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 14篇 |
2018年 | 18篇 |
2017年 | 12篇 |
2016年 | 19篇 |
2015年 | 8篇 |
2014年 | 14篇 |
2013年 | 19篇 |
2012年 | 25篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 9篇 |
2008年 | 7篇 |
2007年 | 14篇 |
2006年 | 7篇 |
2005年 | 9篇 |
2004年 | 6篇 |
2003年 | 13篇 |
2002年 | 10篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1997年 | 4篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 6篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1965年 | 1篇 |
1901年 | 1篇 |
排序方式: 共有317条查询结果,搜索用时 31 毫秒
91.
92.
93.
Lars G. F. Tellnes Lone Ross Gobakken Per Otto Flæte Gry Alfredsen 《Wood material science & engineering》2014,9(3):139-143
AbstractThe outer facade constitutes a substantial volume of the total consumption of materials used in a building and the need for maintenance of the facade makes it especially interesting from a life cycle perspective. The range of wooden materials and products used for facades has different impacts over the life cycle, but the analyses so far have not included a time-adjusted global warming potential (GWP). Wooden facade materials were assessed with respect to their life cycle carbon footprint based on the environmental product declarations (EPD) and adjusted according to EN15804. The results showed low impacts of untreated Scots pine heartwood (≈1 kg CO2-eq. per square meter [m2]), medium for thermally modified Scots pine, coated Norway spruce and oil/copper–organic preservative-treated Scots pine (1–5 kg CO2-eq. per m2) and high for furfurylated Scots pine and acetylated Radiata pine (5–10 kg CO2-eq. per m2). The results with time-adjustment showed that these methods have a potential large effect on the carbon footprint of wooden claddings. The inclusion of biogenic carbon flows and timing seems to be more important than the difference between the product when biogenic carbon is not included. This fact highlights the importance time-adjusted GWP would have for wood products EPDs. 相似文献
94.
Haroldo Henrique de Rezende Neves Felipe Polin dos Reis Flávia Motta Paterno Aline Rocha Guarini Roberto Carvalheiro Lilian Regina da Silva João Ademir de Oliveira Sandra Aidar de Queiroz 《Tropical animal health and production》2014,46(7):1235-1241
The objective of a performance test station is to evaluate the performance of potential breeding bulls earlier in order to decrease the generation interval and increase genetic gain as well. This study evaluates the herd-of-origin influence on end-of-test weight (ETW), average daily weight gain during testing (ADG), average daily weight gain during the adjustment period (ADGadj), rib eye area (REA), marbling (MARB), subcutaneous fat thickness (SFT), conformation (C), early finishing (EF), muscling (M), navel (N) and temperament (T) scores, and scrotal circumference (SC) of Nellore cattle that underwent a performance test. We evaluated 664 animals that participated in the performance tests conducted at the Center for Performance CRV Lagoa between 2007 and 2012. Components of variance for each trait were estimated by an animal model (model 1), using the restricted maximum likelihood method. An alternative animal model (model 2) included, in addition to the fixed effects present in S1, the non-correlated random effect of herd-year (HY). A significant HY effect was observed on ETW, REA, SFT, ADGadj, C, and Cw (p?0.05). The estimated heritability of all traits decreased when the HY effect was included in the model; also, the bull rank, in deciles, changed significantly for traits ETW, REA, SFT, and C. The adjustment period did not completely remove the environmental effect of herd of origin on ETW, REA, SFT, and C. It is recommended that the herd-of-origin effect should be included in the statistical models used to predict the breeding values of the participants of these performance tests. 相似文献
95.
Paloma de Melo Amaral Sebastião de Campos Valadares Filho Edenio Detmann Stefanie Alvarenga Santos Laura Franco Prados Lays Débora Silva Mariz Lyvian Cardoso Alves Ana Clara Baião Menezes Faider Alberto Castaño Villadiego Marco Aurélio Schiavo Novaes Flávia Adriane de Sales Silva 《Tropical animal health and production》2014,46(2):419-425
Beef cattle (24) with an average initial body weight of 417?±?54 kg were assigned in a 2?×?2 factorial design with six repetitions. The factors studied were two levels of CP: 11 (low CP) or 13 % (high CP) in the initial feedlot phase (days 1–36) and in the final phase (days 37–72). After 36 days, half of the bulls fed with each level of CP were selected to reverse the CP level. No interaction was observed (P?>?0.05) between the level of protein in the initial and final phases on the intake of the nutrients evaluated. There was no effect (P?>?0.05) of the protein levels in the initial and final phases on intake of dry matter, organic matter, CP, non-fiber carbohydrates, and total digestible nutrients. No differences were observed among treatments (P?>?0.05) for average daily gain (X = 1.99 kg/day) and carcass traits. We conclude that it is possible to feed Holstein-Zebu crossed bulls with an average daily gain of approximately 2 kg using a fixed level of 11 % CP during the entire feedlot period, and this diet is economically viable and environmentally sound. 相似文献
96.
Rosana C. S. Ogoshi Márcio G. Zangeronimo Jéssica S. Dos Reis Janine França João P. F. Santos Carolina P. Pires Ana F. Chizzotti Adriano C. Costa Lívia G. Ferreira Flávia M. O. B. Saad 《Animal Science Journal》2014,85(5):555-561
This study evaluated the effects of adding an acidifying agent based on phosphoric acid (A), a yeast extract from a specific strain (Saccharomyces cerevisiae) (Y) and the combination of these two additives in food for adult cats. A test was conducted with 24 animals (mean 3.5 years old), mixed breed, weighing 3.72 ± 0.74 kg, kept in individual metabolic cages and distributed in a completely randomized design with a 2 × 2 factorial design (with or without A 0.6% of dry matter, with or without Y 1.5% of dry matter) totalling four treatments and six replicates of each condition. The experimental period was 15 days. The A or the Y reduced (P < 0.01) the dry matter intake, but the effect was not observed when they were associated. The association improved (P < 0.05) the digestibility of dry matter and ashes. The A reduced urine pH (P = 0.05) regardless of the presence of the Y. There was no effect (P > 0.09) on other parameters evaluated. Results of this study show that the isolated use of 0.6% A or 1.5% Y in diets for cats is not recommended. However, the association of these two additives was beneficial in increasing nutrient digestibility. 相似文献
97.
Luís Afonso Marques Claus Flávio Antônio Barca Junior Celso Koetz Junior Gabriel Ribas Pereira Patrícia da Cruz Fávaro Fabio Procópio Ferreira Victor Hugo Gonçalves Galdioli Marcelo Marcondes Seneda Edson Luís de Azambuja Ribeiro 《Reproduction in domestic animals》2021,56(7):1034-1039
The aim of this study was to compare the biometric testicular characteristics, skin thickness and haemodynamics of the testicular artery of 12- and 24-month-old bulls using Doppler ultrasonography, the study was conducted using 48 indicus-taurus animals. The scrotal circumference (SC) and biometry characteristics of the bulls were measured to calculate the testicular volume. Doppler ultrasonography was used to obtain the haemodynamic values of the testicular artery. The skin thickness and volume were lower (p<.01) in the younger bulls (12 months:4.68 ± 0.68 mm; 168.76 ± 47.96 cm3) versus 24 months (5.05 ± 0.89; 499.73 ± 129.24 cm3) animals (p<.01). During diastole, mean velocity was lower in the 12 months (7.98 ± 3.83) than in the 24 months (11.37 ± 4.15) animals (p <.05). The 12-month-old animals had higher pulsatility and resistivity indices (0.49 ± 0.02; 0.51 ± 0.20) compared to the 24-month-old animals (0.32 ± 0.16; 0.40 ± 0.15) (p < .05). The final testicular end velocity was lower in animals with long/moderate-shaped (L/M) (7.31 ± 2.91) than in those moderate/oval-shaped (M/O) (11.48 ± 3.88) testicles (p < .05). Animals with L/M testes presented higher pulsatility values and resistivity indices (0.51 ± 0.05; 0.55 ± 0.04) compared to animals with M/O shape (0.29 ± 0.20; 0.36 ± 0.15). We showed that the blood flow of the supra testicular artery between the two evaluated ages differed, and that 24-month-old bulls presented better thermoregulation capacity. Animals with a long/moderate testicular format presented a greater vascular resistance, which was imposed on the blood flow due to the anatomical differences in the testicular artery, resulting in lower velocity, and indicating better heat dissipation in this format. 相似文献
98.
Alexandre Silveira José A. Pereira Jr. Cristiano Poleto João L. M. P. de Lima Flávio A. Gonçalves Livia A. Alvarenga Jorge M. P. G. Isidoro 《Journal of Soils and Sediments》2016,16(11):2640-2650
Purpose
This study aims to quantify and characterise sediments accumulated in the street gutters in an urban area of Poços de Caldas, Brazil. The main research questions are: What type of urban areas, e.g. those under construction, produce most sediments and what are the main characteristics of such sediments? What differences, e.g. granulometry, can be found in loose and adhered sediments? What trace metals can be found in the sediments?Materials and methods
Fieldwork was carried out in a residential area of Poços de Caldas, Brazil. Ten samplings were conducted between May and August 2013 to collect sediments from road gutters. The collected sediments were then divided into ‘loose’ and ‘adhered’, depending on whether they were collected in a first, gentle, sweeping with soft bristled brush or in a subsequent sweeping with a stiff bristled brush. Granulometric curves were drawn for both types of sediments. Fine sediment analyses (≤63 μm) were performed on samples from the last five samplings. Two techniques were used to look for trace elements: energy dispersive X-ray fluorescence (EDXRF) and inductively coupled plasma-atomic emission spectrometry (ICP-AES).Results and discussion
Larger amounts of sediments were collected after lower intensity rainfall events. Higher intensity events seemed to wash the sediments away. A correlation was found between areas under construction and sediment mass production. A characteristic range of granulometries (medium sand), found in our study is in accordance with studies by other authors. An important presence of heavy metals (Cr, Cd, Pb, Zn, Ni and Cu) was detected and characterised. As and Sn were also detected even though they are not often mentioned in the literature on urban soil pollutants.Conclusions
Areas under construction were found to produce more sediments than other areas. The trace metals found in highest concentrations were Pb and As. The heavy metal concentration decreases after wet periods, showing that they are carried by runoff. It is expected that this study may serve as an input for establishing diffuse pollution control and mitigation strategies for the accumulation of pollutants in the urban environment.99.
Monção Flávio Pinto Costa Marco Aurélio Morais Soares Rigueira João Paulo Sampaio de Sales Eleuza Clarete Junqueira Leal Dijair Barbosa da Silva Marcos Felipe Pereira Gomes Virgílio Mesquita Chamone Julieta Maria Alencar Alves Dorismar David da Cunha Siqueira Carvalho Cinara Murta José Eduardo Jardim Júnior Vicente Ribeiro Rocha 《Tropical animal health and production》2020,52(1):235-241
Tropical Animal Health and Production - The objective of this study was to evaluate the productivity, productive efficiency, and nutritional value of the elephant grass cultivar BRS capiaçu... 相似文献
100.
Radan Elvis Matias de Oliveira Giovanna Almeida Santoro Augusto Carlos da Bôaviagem Freire Fernanda Löffler Niemeyer Attademo Stella Almeida Lima Aline da Costa Bomfim Ana Bernadete Lima Fragoso Flávio José de Lima Silva Simone Almeida Gavilan Moacir Franco de Oliveira 《Anatomia, histologia, embryologia》2020,49(1):25-30
The aortic arrangement is an important structure associated with the maintenance of homeostasis. Based on this information, this study was conducted to describe the collateral arteries of the aortic arch of Antillean manatee and define the standard model for the species. Three specimens, an adult male, adult female and a male neonate, all strandings on the coast of the state of Rio Grande do Norte, Brazil, were used. The study was performed in the Laboratory of Morphophysiology of Vertebrates of the Federal University of Rio Grande do Norte, where in situ photographs were taken to demonstrate their topography. Subsequently, their hearts were removed and fixed in 10% formaldehyde and after 72 hr were dissected and analysed, obtaining schematic drawings and photographs of the vascular arrangement. The aortic arch was represented by three collateral arteries identified as the brachiocephalic trunk, left common carotid artery and left subclavian artery. This arrangement was similar to that found for other sirenians, and yet, for other mammals like hooded seal, murine, margarita island capuchin, black-handed tamarin, Mongolian gerbil and human. The morphological similarity presented in this study with different species of mammals, including humans, may contribute valuable information from an evolutionary point of view. 相似文献