全文获取类型
收费全文 | 588篇 |
免费 | 66篇 |
国内免费 | 2篇 |
专业分类
林业 | 14篇 |
农学 | 28篇 |
基础科学 | 2篇 |
105篇 | |
综合类 | 35篇 |
农作物 | 26篇 |
水产渔业 | 44篇 |
畜牧兽医 | 348篇 |
园艺 | 13篇 |
植物保护 | 41篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 18篇 |
2019年 | 21篇 |
2018年 | 35篇 |
2017年 | 14篇 |
2016年 | 23篇 |
2015年 | 21篇 |
2014年 | 29篇 |
2013年 | 48篇 |
2012年 | 11篇 |
2011年 | 28篇 |
2010年 | 30篇 |
2009年 | 25篇 |
2008年 | 38篇 |
2007年 | 23篇 |
2006年 | 36篇 |
2005年 | 21篇 |
2004年 | 26篇 |
2003年 | 16篇 |
2002年 | 17篇 |
2001年 | 15篇 |
2000年 | 16篇 |
1999年 | 16篇 |
1998年 | 20篇 |
1997年 | 13篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1972年 | 2篇 |
排序方式: 共有656条查询结果,搜索用时 15 毫秒
21.
E López Agüero N Bosch Bosch C Barrera Vázquez B López Ruiz 《Journal of agricultural and food chemistry》1999,47(11):4682-4685
A new, simple, precise, and rapid ion chromatography (IC) method has been developed to determine chloride in mustard sauces using a mixture of phthalic acid, acetone, and water adjusted to pH 5.0 as eluent. Conductometric detection was carried out. The retention time for chloride was 1.5 min. Linearity was obtained up to a concentration level of 100 mg/L NaCl. The method was statistically evaluated for accuracy and precision after being used to assay the chloride from mustard sauces. Within the same samples, the chloride levels obtained by IC were compared with the sodium concentrations quantified by atomic absorption spectrophotometry. 相似文献
22.
Seed yield is a major breeding target in tetraploid red clover. We investigated if marker‐assisted parentage analysis can identify progeny plants with two high seed‐yielding parents in tetraploid red clover and if this technique is more advantageous than traditional half‐sib selection. Parentage analysis was successfully performed on the progeny from the 10% highest seed‐yielding genotypes from a second‐cycle family selection trial: 16.0% of progeny were identified with a high seed‐yielding father. However, progeny plants with two high seed‐yielding parents did not produce more seeds than traditionally selected progeny (27.3 g vs. 30.7 g/plant, respectively). The 10% highest seed‐yielding genotypes displayed on average 2% self‐fertilization. Four genotypes were self‐fertile with individual selfing rates up to 20%. Our results discourage the use of marker‐assisted parentage analysis to improve seed yield in tetraploid red clover when the material has been preselected for seed yield. Breeders should be aware that intensive selection for seed yield in tetraploid red clover may inadvertently lead to selection for increased self‐fertility, which may increase inbreeding in the long term. 相似文献
23.
Ortiz J Ruiz de Ybañez MR Abaigar T Goyena M Espeso G Cano M Alonso F 《The Veterinary record》2001,149(1):12-15
Seven different methods of administering ivermectin to gazelles were compared: subcutaneous injection, direct oral administration, administration in individual feeds, administration in a herd feed, direct oral administration of a second ivermectin formulation, administration in individual water supplies, and administration in the herd's water supply. The first five treatments were effective, as monitored by faecal egg count reduction tests, and administration in individual feeds or in a herd feed avoided the need to capture the animals, with the attendant risk of mortality. Of the factors associated with the recipients (species, sex, age and inbreeding coefficient) age was the only significant factor for the efficacy of the treatment. Oral or subcutaneous, individual or collective, and direct or indirect administrations were equally satisfactory for the treatment of all the parasite groups studied. Only when parasitic problems were due to Nematodirus species did direct administration to individual animals appear to be preferable. 相似文献
24.
YC Marquez CS Galina N Moreno H Ruiz A Ruiz H Merchant 《Reproduction in domestic animals》2005,40(6):553-558
In order to optimize the production of embryos under tropical conditions and to test a possible seasonal effect on embryo quality, 40 Zebu cows were superovulated during the dry season (April to May) and during the rainy season (July to August). A total of 116 (average 2.7/cow) and 83 embryos (3.5 average/cow) were obtained during the respective seasons. After classification as good, fair or poor quality, embryos were tested based on their ultrastructural differences (n = 53 dry season 16 good, 20 fair and 17 poor and n = 61 rainy season 21 good, 20 fair and 20 poor) and their degree of apoptosis using the TUNEL technique (n = 30 during the dry season and n = 55 in the rainy season). Structural characteristics determining embryo quality varied between good and fair quality embryos. No difference, however, was observed between good, fair and poor quality embryos from the two seasons. The number of TUNEL-positive cells was different among embryos (p < 0.001), being lower in labelled cells of good quality embryos regardless of the season. Fewer apoptotic cells were observed in embryos assigned in all three quality levels during the rainy season (p < 0.001). Ultrastructural evaluations confirmed the results obtained by TUNEL. Cryopreserved embryos of good (n = 25 in each season) and fair quality (n = 11 dry season; n = 17 rainy season) showed a significant decrease of TUNEL-positive cells during the rainy season (p < 0.05). Results suggest that embryos collected in the dry season have more cellular damage in contrast; embryos cryopreserved in the rainy season appeared morphologically better equipped to result in a pregnancy following transfer. 相似文献
25.
26.
27.
Ruiz A Molina JM González J Martínez-Moreno FJ Gutiérrez PN Martínez-Moreno A 《Veterinary research》2003,34(4):435-443
The use of cysteine proteinases from Fasciola hepatica adult flukes for the serodiagnosis of caprine fasciolosis by means of an indirect ELISA test was studied. Two proteolytic fractions from adult fluke homogenates, with apparent molecular weights of 28 and 34 kDa (P28 and P34 respectively), were characterised as cysteine proteinases using azocasein assays and gelatin gel analysis. Both P28 and P34 fractions were electroluted and used as antigens in two different indirect ELISA tests. Serum IgG levels against P28 and P34 in goats given an experimental primary infection with 200 metacercariae or in goats given two experimental infections with 200 metacercariae were determined and compared with those observed in an uninfected control group. ELISA tests using both cysteine proteases showed a rapid and consistent detection of specific IgG in all experimentally infected goats. The IgG response to P28 was the first to be detected as early as 2-3 weeks post-infection and remained elevated throughout the experiment. The response to P34 was detected later (4-6 wpi) and disappeared in some animals at 18 wpi, while flukes were still present in the bile ducts. No significant differences were observed between the anti-P28 and anti-P34 IgG responses between animals receiving a primary or a challenge infection. The results of our study, although preliminary, are promising since the P28 ELISA described here may be a reliable method for the immunodiagnosis of F. hepatica infection in goats. 相似文献
28.
Ortuño A Castellà J Marco I Ruiz M Lavín S 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2003,50(5):253-254
Ungulates are involved in the epidemiology of Borreliosis as maintenance hosts for vector tick species. We evaluated the prevalence of antibodies to Borrelia burgdorferi sensu lato in two different populations of southern chamois in Spain. Forty-six sera (40.4%) were positive at titres >/=1 : 64 using an indirect immunofluorescence assay (IFAT). 相似文献
29.
30.
1. Eggs were stored for two different times at varying temperatures. The effects on hatchability, chick weight at hatch and hatching time were examined in two broiler breeder lines from 33 to 58 weeks of age. 2. Short storage (1 to 3 d). Storage at 20 degrees C compared with 16.5 degrees C reduced hatchability of all eggs set. No effect was observed on hatchability of fertile eggs, hatching time or chick weight. 3. Long storage (9 to 11 d). Storage at 16.5 degrees C compared with 10 degrees C decreased both hatchability of fertile eggs and chick weight at hatch. Incidence of early embryonic death increased and incubation time decreased at 16.5 degrees C compared with 10 degrees C. 4. Chicks from morning eggs were heavier than those from afternoon eggs irrespective of storage conditions. 5. Hatchability (all eggs set and fertile eggs) and chick weight varied with hen age irrespective of storage conditions. During long storage, hatching time varied with hen age independently of breeder line, storage temperature or egg laying time. 6. Hatchability (all eggs set and fertile eggs) was higher in line A than in line B. Line B eggs hatched later and produced heavier chicks than line A eggs irrespective of storage time. 相似文献