全文获取类型
收费全文 | 133篇 |
免费 | 6篇 |
专业分类
林业 | 1篇 |
农学 | 9篇 |
56篇 | |
综合类 | 25篇 |
农作物 | 16篇 |
水产渔业 | 14篇 |
畜牧兽医 | 15篇 |
植物保护 | 3篇 |
出版年
2021年 | 2篇 |
2018年 | 2篇 |
2016年 | 3篇 |
2014年 | 4篇 |
2013年 | 1篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 13篇 |
2007年 | 11篇 |
2006年 | 13篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1965年 | 1篇 |
1963年 | 1篇 |
1956年 | 1篇 |
1955年 | 1篇 |
1953年 | 1篇 |
1945年 | 1篇 |
1928年 | 1篇 |
1927年 | 1篇 |
1921年 | 1篇 |
1909年 | 2篇 |
1902年 | 1篇 |
1899年 | 2篇 |
1884年 | 1篇 |
排序方式: 共有139条查询结果,搜索用时 15 毫秒
1.
2.
3.
Fleming LE Jerez E Stephan WB Cassedy A Bean JA Reich A Kirkpatrick B Backer L Nierenberg K Watkins S Hollenbeck J Weisman R 《Marine drugs》2007,5(4):208-219
With an apparent increase of harmful algal blooms (HABs) worldwide, healthcare providers, public health personnel and coastal managers are struggling to provide scientifically-based appropriately-targeted HAB outreach and education. Since 1998, the Florida Poison Information Center-Miami, with its 24 hour/365 day/year free Aquatic Toxins Hotline (1–888–232–8635) available in several languages, has received over 25,000 HAB-related calls. As part of HAB surveillance, all possible cases of HAB-related illness among callers are reported to the Florida Health Department. This pilot study evaluated an automated call processing menu system that allows callers to access bilingual HAB information, and to speak directly with a trained Poison Information Specialist. The majority (68%) of callers reported satisfaction with the information, and many provided specific suggestions for improvement. This pilot study, the first known evaluation of use and satisfaction with HAB educational outreach materials, demonstrated that the automated system provided useful HAB-related information for the majority of callers, and decreased the routine informational call workload for the Poison Information Specialists, allowing them to focus on callers needing immediate assistance and their healthcare providers. These results will lead to improvement of this valuable HAB outreach, education and surveillance tool. Formal evaluation is recommended for future HAB outreach and educational materials. 相似文献
4.
Allelic losses and gains during translocations of a high conservation value fish,Coregonus lavaretus
Kim Præbel Colin W. Bean Jennifer A. Dodd Elizabeth C. Etheridge Andrew R.D. Gowans Rune Knudsen Alexander A. Lyle Peter S. Maitland Ian J. Winfield Colin E. Adams 《水产资源保护:海洋与淡水生态系统》2021,31(9):2575-2585
- The use of translocations to establish new or ‘refuge’ populations for species with high conservation value is controversial but widely used in conservation management. One of the risks of this approach is that an establishing population does not adequately capture the genetic diversity of the donor gene pool. This effect, rarely examined, is tested here.
- In this study the genetic consequences of two conservation translocations after five generations (16 years) of the European whitefish, Coregonus lavaretus, were quantified. Both translocations were made using almost the same genetic groups and thus represent a partly replicated natural study.
- Analysis of 12 informative microsatellites showed that expected heterozygosity, the mean number of alleles per locus and allelic richness did not differ between donor and translocated populations. There was also no loss of heterozygosity in the translocated populations, nor deviations from Hardy–Weinberg equilibrium expectations, nor signs of linkage disequilibrium.
- All populations were genetically differentiated but pairwise FST values were low, indicating that the magnitude of divergence was small.
- There was no evidence of inbreeding but there were significant differences in private allelic richness between donor and translocated populations. Of 50 alleles found in the donor population, 16% of the rarer alleles were lost in one translocated population and 8% in the other.
- Allele loss without a reduction in heterozygosity strongly points to stochastic drift effects having occurred following translocation. The evidence indicates that alleles that were not detected in the donor population have arisen de novo in the translocated populations.
- It is concluded that conservation translocations comprising even a modest number of propagules can successfully capture a high proportion of genetic variation of the host population, and that reduced genetic variation in the translocated population may be mitigated by the emergence of new variation over short time periods.
5.
Characterization of waxy grain sorghum lines in relation to granule-bound starch synthase 总被引:4,自引:0,他引:4
The waxy phenotype, associated with endosperm containing little or no amylose, has been recognized in sorghum (Sorghum bicolor L. Moench) since 1933. Although variants of the waxy gene are well characterized in other cereals, the waxy trait has been
assumed to be controlled by a single allele, wx, in sorghum. Recent improvements in technologies encourage re-examination of the waxy sorghums. The objectives of this research
were therefore to identify and characterize sorghum lines with differing waxy alleles and to describe the actions of those
alleles in crosses. Grain of eight waxy sorghum lines (BTxARG1, BTx630, Tx2907, B.9307, 94C274, 94C278, 94C289, 94C369), three
wild-type checks (BWheatland, RTx430, BN122), and F2 families from crosses among a subset of these lines were evaluated for presence or absence of granule-bound starch synthase
(GBSS), the gene product of the wx locus, and wild-type vs. waxy endosperm. The F2 segregation ratios were tested for fit to a 3:1 ratio using Chi-square analyses. Two distinctly different naturally occurring
waxy alleles were identified: One with no GBSS (GBSS−), and one with apparently inactive GBSS present (GBSS+). We propose
that the waxy allele with no GBSS be designated wxa, and that waxy allele with apparently inactive GBSS present be designated wxb. These two alleles are located in close proximity on the waxy locus. The wxb allele is dominant to the wxa allele in terms of GBSS production, and both are recessive to the wild-type Wx in terms of amylose content.
The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged. 相似文献
6.
Summary Plants of tetraploid Festuca pratensis var. apennina (2n=28) collected from Switserland and Northern Italy produced few inflorescences when grown in the field and under glasshouse conditions. The effects of winter and spring treatments upon reproductive growth were investigated and it was concluded that exposure to low winter temperatures and the control of tiller density in the spring were two important factors controlling the production of inflorescences. A procedure for the production of seed is suggested which will allow breeders to obtain efficient multiplication of collected plant material. 相似文献
7.
8.
Investigation and optimization of the factors influencing sorghum protein extraction 总被引:3,自引:0,他引:3
To optimize the extraction of sorghum proteins, several variables were examined: sample-to-solvent ratio, detergent type and concentration, reducing agent type and concentration, extraction time, and buffer pH and concentration. Samples were quantified and characterized by RP-HPLC, FZCE, and nitrogen analysis. These studies revealed that pH, detergent type, reducing agent type, and sample-to-solvent ratio all had significant effects on the levels of protein extracted. Increasing SDS concentration (2%) and solvent-to-flour ratio (20:1) with multiple 5 min extracts reduced extraction time by 35-80% while still extracting the same levels of total protein relative to the control methodology. Reproducibility using the multiple extractions was found to be excellent with relative standard deviations of <2% for consecutive extractions. 相似文献
9.
10.
Bean A Williamson J Cursons RT 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2004,51(6):285-287
Escherichia coli, a Gram-negative environmental pathogen associated with bovine mastitis was isolated from the milk of 34 symptomatic cows that had been diagnosed with clinical mastitis. Eighty isolates were obtained over a 17-month period and these isolates were screened by DNA amplification for the following E. coli virulence genes: cnf1, cnf2, eaeA, eagg, einv, ltx1, stx1, stx2 and vt2e. Thirty of the bacterial isolates, obtained from 23 different cows, had toxin genes identified in their DNA. The most common virulence gene detected was stx1, with a prevalence of 31%, followed by cnf2 (7.5%), vt2e (6.25%) and eaeA (4%). The possession of different virulence genes by the bacterial isolates had no discernable impact on the health status of the cows as there was no correlation between the potential for toxin production by the E. coli isolates and the systemic clinical condition of the respective infected cows. 相似文献