全文获取类型
收费全文 | 287篇 |
免费 | 29篇 |
专业分类
林业 | 20篇 |
农学 | 7篇 |
40篇 | |
综合类 | 19篇 |
农作物 | 30篇 |
水产渔业 | 39篇 |
畜牧兽医 | 134篇 |
园艺 | 6篇 |
植物保护 | 21篇 |
出版年
2023年 | 5篇 |
2022年 | 14篇 |
2021年 | 19篇 |
2020年 | 12篇 |
2019年 | 18篇 |
2018年 | 12篇 |
2017年 | 20篇 |
2016年 | 13篇 |
2015年 | 10篇 |
2014年 | 17篇 |
2013年 | 18篇 |
2012年 | 24篇 |
2011年 | 19篇 |
2010年 | 7篇 |
2009年 | 11篇 |
2008年 | 16篇 |
2007年 | 13篇 |
2006年 | 12篇 |
2005年 | 6篇 |
2004年 | 8篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 3篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有316条查询结果,搜索用时 15 毫秒
101.
102.
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
103.
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
104.
Lindenberg AM Larsson J Sokolowski-Tinten K Gaffney KJ Blome C Synnergren O Sheppard J Caleman C Macphee AG Weinstein D Lowney DP Allison TK Matthews T Falcone RW Cavalieri AL Fritz DM Lee SH Bucksbaum PH Reis DA Rudati J Fuoss PH Kao CC Siddons DP Pahl R Als-Nielsen J Duesterer S Ischebeck R Schlarb H Schulte-Schrepping H Tschentscher T Schneider J von der Linde D Hignette O Sette F Chapman HN Lee RW Hansen TN Techert S Wark JS Bergh M Huldt G van der Spoel D Timneanu N Hajdu J Akre RA Bong E 《Science (New York, N.Y.)》2005,308(5720):392-395
The motion of atoms on interatomic potential energy surfaces is fundamental to the dynamics of liquids and solids. An accelerator-based source of femtosecond x-ray pulses allowed us to follow directly atomic displacements on an optically modified energy landscape, leading eventually to the transition from crystalline solid to disordered liquid. We show that, to first order in time, the dynamics are inertial, and we place constraints on the shape and curvature of the transition-state potential energy surface. Our measurements point toward analogies between this nonequilibrium phase transition and the short-time dynamics intrinsic to equilibrium liquids. 相似文献
105.
Suicide transport: destruction of neurons by retrograde transport of ricin, abrin, and modeccin 总被引:5,自引:0,他引:5
Certain toxic lectins, including ricin, are retrogradely transported along neuronal processes to the cell body where they inactivate ribosomes, resulting in neuronal death. This process of "suicide transport" suggests a powerful new experimental strategy for solving neurobiological problems. 相似文献
106.
Rauch A Thiel CT Schindler D Wick U Crow YJ Ekici AB van Essen AJ Goecke TO Al-Gazali L Chrzanowska KH Zweier C Brunner HG Becker K Curry CJ Dallapiccola B Devriendt K Dörfler A Kinning E Megarbane A Meinecke P Semple RK Spranger S Toutain A Trembath RC Voss E Wilson L Hennekam R de Zegher F Dörr HG Reis A 《Science (New York, N.Y.)》2008,319(5864):816-819
Fundamental processes influencing human growth can be revealed by studying extreme short stature. Using genetic linkage analysis, we find that biallelic loss-of-function mutations in the centrosomal pericentrin (PCNT) gene on chromosome 21q22.3 cause microcephalic osteodysplastic primordial dwarfism type II (MOPD II) in 25 patients. Adults with this rare inherited condition have an average height of 100 centimeters and a brain size comparable to that of a 3-month-old baby, but are of near-normal intelligence. Absence of PCNT results in disorganized mitotic spindles and missegregation of chromosomes. Mutations in related genes are known to cause primary microcephaly (MCPH1, CDK5RAP2, ASPM, and CENPJ). 相似文献
107.
Presence of laminin receptors in Staphylococcus aureus 总被引:47,自引:0,他引:47
A characteristic feature of infection by Staphylococcus aureus is bloodstream invasion and widespread metastatic abscess formation. The ability to extravasate, which entails crossing the vascular basement membrane, appears to be critical for the organism's pathogenicity. Extravasation by normal and neoplastic mammalian cells has been correlated with the presence of specific cell surface receptors for the basement membrane glycoprotein laminin. Similar laminin receptors were found in Staphylococcus aureus but not in Staphylococcus epidermidis, a noninvasive pathogen. There were about 100 binding sites per cell, with an apparent binding affinity of 2.9 nanomolar. The molecular weight of the receptor was 50,000 and pI was 4.2. Eukaryotic laminin receptors were visualized by means of the binding of S. aureus in the presence of laminin. Prokaryotic and eukaryotic invasive cells might utilize similar, if not identical, mechanisms for invasion. 相似文献
108.
Construction of a genetic map of melon with molecular markers and horticultural traits, and localization of genes associated with ZYMV resistance 总被引:12,自引:0,他引:12
Yael Danin-Poleg Yaakov Tadmor Galil Tzuri Noa Reis Joseph Hirschberg Nurit Katzir 《Euphytica》2002,125(3):373-384
Abstract: A partial linkage map of melon was constructed from a cross between PI414723 and Dulce. Twenty-two SSR, 46RAPD,
2 ISSR markers and four horticultural markers [female flower form (a), Fusarium resistance, striped epicarp (st), and fruit flesh pH (pH)] were analyzed in an F2/F3 population to produce a map spanning 14 linkage groups. We report for the first time map positions for the st, a, and pH genes. One SSR marker was tightly linked to pH. Mapping the a gene for the female flower form to molecular linkage group 4 enabled the merging of the map of horticultural traits with
the of molecular markers in this region. Using the 22 SSR markers of this map, two of the three postulated ZYMV resistance
genes were located using a BC1 population (PI414723 recurrent parent). One SSR marker was tightly linked to a ZYMV resistance gene, designated Zym-1.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
109.
Cunha Stéfane S. Orrico Junior Marco A. P. Reis Ricardo A. Orrico Ana C. A. Schwingel Alice W. Reis Sirio D. S. Silva Mabio S. J. 《Tropical animal health and production》2020,52(2):871-879
Tropical Animal Health and Production - The increase in haylage production leads to the search for additives that improve its fermentation and nutritional value. This study aimed to assess the... 相似文献
110.
Jeana Pereira da Silva Sheila Canevese Rahal Maria Cristina Reis Castiglioni Raphael Augusto Baldissera Gonçalves Danuta Pulz Doiche Anneke Moresco Maria Jaqueline Mamprim Luiz Carlos Vulcano 《Anatomia, histologia, embryologia》2020,49(4):541-549
This study aimed to evaluate normal features of the heart and lower respiratory tract in toco toucans by means of radiography and helical computed tomography (CT) scanner. Fifteen healthy adult toco toucans (Ramphastos toco), 10 females and 5 males, average body mass of 650 g were studied. CT examination as well as right lateral and ventrodorsal radiographic examinations of the coelomic cavity were performed under chemical restraint. Heart, lungs, air sacs, trachea and syrinx were analysed. The mean values of heart length, heart width and thoracic cavity in radiographs were, respectively, 23.76 mm, 25.94 mm and 48.87 mm. In both X-rays and CT scans, the lung parenchyma had honeycomb-like pattern. The topographic areas of the anterior and posterior air sacs were visualized as dark and air-filled spaces in X-rays. On CT evaluation, the air sacs occupied a larger area in the coelomic cavity compared to X-ray. In the lateral radiographic view, the cervical part of the trachea was positioned more ventrally in the transition from cervical to thoracic regions showing a V-shaped appearance. In all CT planes was visible division of the trachea into the right and left main bronchi at the level of 3rd thoracic vertebra. The syrinx was difficult to visualize in X-rays, but on CT it was easily identified in axial slice. In conclusion, the normal features of toco toucan's heart and lower respiratory tract that were determined on X-rays and CT scans are useful to compare with sick toco toucans, as well as other bird species. 相似文献