全文获取类型
收费全文 | 89篇 |
免费 | 3篇 |
专业分类
林业 | 12篇 |
农学 | 9篇 |
31篇 | |
综合类 | 3篇 |
农作物 | 4篇 |
水产渔业 | 5篇 |
畜牧兽医 | 19篇 |
园艺 | 3篇 |
植物保护 | 6篇 |
出版年
2024年 | 1篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 8篇 |
2012年 | 6篇 |
2011年 | 7篇 |
2010年 | 4篇 |
2009年 | 7篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2002年 | 4篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有92条查询结果,搜索用时 15 毫秒
1.
本研究利用同源克隆法以苹果属平邑甜茶和杂种后代叶片为试验材料,克隆得到4个SERK基因家族片段,并分析了SERKs家族基因在平邑甜茶和杂种后代不同器官和组织中的表达情况。研究结果表明:分离获得的4个SERK基因家族片段的氨基酸序列与模式植物拟南芥、烟草等植物的同源性均在84%以上,同时与其他物种的氨基酸序列进行Blast比对都具有较高的同源性;RT-PCR定量分析结果表明SERK1、SERK2、SERK3、SERK4基因主要在生殖器官中表达。因此,推测SERKs基因在平邑甜茶和杂种后代生殖发育过程中起着重要的调控作用。本研究结果为进一步揭示无融合生殖的发生机理奠定了基础。 相似文献
2.
Suman Lata Verma Chris Penfold 《Communications in Soil Science and Plant Analysis》2017,48(4):459-468
With diminishing world reserves of phosphorus (P) deposits and rising fertilizer prices, it is important to find alternate sources of P for crops. The aim of this research was to evaluate the effect of four different composts C1 (animal manure and straw), C2 (garden waste), C3 (wood chips and bark), and C4 (kitchen waste) on soil P pools and P uptake by wheat on 14, 28, and 72 days after compost application. The composts were applied as a 2.5 cm thick layer on the soil surface. During sampling, only the soil underlying compost was sampled. Soil pH and total organic carbon were not affected by the amendments. Soil respiration was significantly higher in compost-amended soils compared with the unamended soil except with C4 on day 72. Addition of composts increased plant growth, and P uptake being highest on day 72 with C1 and C4. With little effect on available P concentration on day 14, there was a conversion of organic P into inorganic P in the compost treatments suggesting net mineralization of organic P on day 28. On day 72, the concentrations of the less labile P forms were higher in the compost treatments compared with the unamended suggesting precipitation and fixation as well as synthesis of organic P. This study showed that mulching with composts having high available and total P concentrations can provide plants with P and also increase soil P concentrations which could reduce the fertilizer requirement for the following crop. 相似文献
3.
4.
Antibodies to Coxiella burnetii have been found in the Danish dairy cattle population with high levels of herd and within herd seroprevalences. However, the prevalence of antibodies to C. burnetii in Danish beef cattle remains unknown. The objectives of this study were to (1) estimate the prevalence and (2) identify risk factors associated with C. burnetii seropositivity in Danish beef and dairy cattle based on sampling at slaughter. 相似文献
5.
Developmentally specific expression of Rhizobium spp. genes involved in symbiotic N2 fixation is known to operate through cascade regulation of various nif and fix operons. Fusion constructs of lacZ under symbiotic promoters P1 (for nifHDK operon) and P2 (for fixABCX operon) of Rhizobium meliloti were mobilized into Rhizobium spp. (Cicer) strains Rcd301 and RCR13. The assays for -galactosidase activity to monitor the expression of lacZ under these promoters was performed in host backgrounds of Escherichia coli, R. meliloti, and Rhizobium spp. (Cicer). The enzyme assays indicated significant levels of expression from P1 and P2 promoters in chickpea rhizobia, specifically in symbiotic cells from nodules. However, as in R. meliloti, these promoters did not induce strong expression in free-living cells of Rhizobium spp. (Cicer). This indicates functional homology of R. meliloti promoters in rhizobium spp. (Cicer). Functional cross-reactivity of trans regulatory factors like NtrA, NtrC, and NifA between these rhizobia seems evident from the nodule-specific expression of P1 and P2 cis elements. 相似文献
6.
The aim of this study was to compare three different enzyme-linked immunosorbant assays (recombinant major antigenic protein 2 (rMAP2)-ELISA, the Immunocomb (Biogal, Israel) and the Snap 3Dx assay (IDEXX Laboratories Inc., USA)) with the indirect immunofluorescent antibody test in detecting anti-Ehrlichia canis immunoglobulin-G (IgG) antibodies. Samples tested were collected from dogs suspected to be naturally infected with E. canis and from experimentally infected dogs.When qualitative results (positive/negative) were compared, there was an overall agreement of 81% (54/67) between the indirect immunofluorescence antibody (IFA) test and the rMAP2-ELISA. An overall agreement of 94% (63/67) was found between the IFA test and the Immunocomb, and an overall agreement of 91% (61/67) was found between the IFA test and the Snap 3Dx assay. In 50 of 67 (74.6%) samples tested, complete agreement in the qualitative results was found in all four tests. Sixteen of 17 samples with disagreement in the qualitative results were found to have IFA titers of 1:320 or less. The sensitivities and specificities of the tests were found to be 0.71 and 0.85 for the rMAP2-ELISA, 0.86 and 0.98 for the Immunocomb, and 0.71 and 1.00 for the Snap 3Dx assay.The tests performed in this study were found to be highly specific in detecting E. canis antibodies. Their sensitivity was found to be low with sera having IFA titers of < or =1:320, while high with sera having titers greater than 1:320. Repeating the serological tests 1-2 weeks after the first antibody assay may overcome the sensitivity problem with titers of < or =1:320. 相似文献
7.
Jeetendra Prakash Aryal Dil Bahadur Rahut M. L. Jat Sofina Maharjan Olaf Erenstein 《Journal of Crop Improvement》2018,32(4):477-492
Laser land leveling has been increasingly adopted in the irrigated rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping system in the state of Haryana (India), located in the north-western Indo-Gangetic Plains. Still, many farmers have applied it to only a fraction of their land. In this study, we used data collected from 621 farm households in Haryana and applied a double-hurdle model for assessing the factors that determine the adoption and intensity of laser-leveling technology. The results show that large land holders are more likely to laser level their farm land; however, we found a negative association between land holdings and the proportion of laser-leveled land. Information about technology through farmer-to-farmer communication and through private traders, participation in agricultural training and membership in local agricultural institutions increased both the likelihood and the intensity of adoption. Our findings call for a closer collaboration among the various stakeholders, specifically to promote farmer-to-farmer communication through increased participation in local institutions and increase the rate of adoption of laser leveling technology. 相似文献
8.
Study of genetic diversity in Indian and exotic sesame (Sesamum indicum L.) germplasm using random amplified polymorphic DNA (RAPD) markers 总被引:1,自引:0,他引:1
Fifty-eight accessions of sesame (Sesamum indicum L.), an important oil seed crop of the tropics and subtropics were analysed using random amplified polymorphic DNA (RAPD)
technique. The material analysed comprised 36 collections from 18 different states of India and four adjoining countries of
the Indian subcontinent, and 22 exotic accessions from 21 sesame growing countries around the world. The results from PCR
amplifications with the selected 24 random 10-mer primers were statistically analysed. The value of Jaccard’s similarity coefficients
ranged from 0.19 to 0.89. The results indicated the presence of high level of genetic diversity. However, the extent of genetic
diversity was greater in the collections from Indian subcontinent as compared to the exotics. Among the Indian accessions,
the collections from Rajasthan and North-eastern states were highly diverse. The phenetic analysis grouped 48 out of 58 accessions
in six clusters and the remaining highly diverse accessions were placed outside these close-knit clusters. The Bootstrap estimates
obtained by Wagner parsimony analysis were significant for seven out of 49 nodes in the majority-rule consensus tree (<95%
occurrence). The results of both the analyses were, however, broadly comparable when the constitution of the individual clusters
were considered. The principal components analysis indicated that the first two components accounted for only 21% of the total
variations and in order to explain <75% of variations 18 components were required. The high level of genetic diversity prevalent
among the Indian collections is probably indicative of the nativity of this crop species. Similarly, the relatively lower
level of polymorphism in exotic germplasm could be ascribed to the comparatively recent introductions of limited germplasm
of this crop into some of the non-traditional sesame growing countries.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
10.
A. K. Dang Suman Kapila Maneesh Purohit Charan Singh 《Tropical animal health and production》2009,41(7):1213-1217
Colostrum samples were collected from 8 Murrah buffaloes on days 1, 2, 3, 4 and 5 after calving. Levels of IgG averaged 54.0 mg/ml
at calving, then decreased significantly (P < 0.01). IgA and IgM on day 1 were 3.22 mg/ml and 5.22 mg/ml, respectively; both
decreased during the first five days after calving. Values of IgA and IgM were higher than those reported in cows. SCC values,
which were high at calving (500 000 per ml), reduced significantly (P < 0.01) on day 2, then decreased slightly until day
5 (180 000 per ml). At calving, macrophages were the most prominent cells in buffalo colostrum, followed by lymphocytes and
neutrophils. Phagocytic activity was 23% at calving and reduced significantly (P < 0.01) to 14% on day 5. Phagocytic index
was highest in the first colostrum, and then decreased non-significantly. 相似文献