全文获取类型
收费全文 | 250篇 |
免费 | 9篇 |
专业分类
林业 | 31篇 |
农学 | 25篇 |
基础科学 | 5篇 |
68篇 | |
综合类 | 11篇 |
农作物 | 49篇 |
水产渔业 | 9篇 |
畜牧兽医 | 37篇 |
园艺 | 7篇 |
植物保护 | 17篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 22篇 |
2017年 | 24篇 |
2016年 | 26篇 |
2015年 | 6篇 |
2014年 | 12篇 |
2013年 | 33篇 |
2012年 | 13篇 |
2011年 | 12篇 |
2010年 | 15篇 |
2009年 | 13篇 |
2008年 | 13篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 1篇 |
1999年 | 1篇 |
1996年 | 4篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1984年 | 1篇 |
1983年 | 5篇 |
排序方式: 共有259条查询结果,搜索用时 15 毫秒
21.
The use of vermicompost as a biological fertilizer under salinity stress conditions was tested in this research. Accordingly, the seeds of Medicago rigidula were grown in the greenhouse. The experiment was performed based on factorial arrangement in a completely randomized design using 5 replications. Application rates of vermicompost were 0, 10, 20 and 30%. Salinity stress was conducted in three levels (0, 50 and 100 mM sodium chloride (NaCl)). The highest and the lowest values of the plant survival capacity (%), shoot dry weight (g), leaf relative water content (LRWC) (%), total chlorophyll content (%), leaf area (cm2), total nitrogen content (TNC) (%) and potassium (K) content (%) of the plant tissues were found in VC4 × SL1 and VC1 × SL3 treatments, respectively. Whereas, the maximum and minimum values of root dry weight and root:shoot ratio were seen in VC1 × SL3 and VC4 × SL1 treatments, respectively. 相似文献
22.
23.
Tapinoma indicum (Forel) (Hymenoptera: Formicidae) is a nuisance pest in Asia countries. However, studies on T. indicum are limited, especially in the field of molecular biology, to investigate the species characteristic at the molecular level. This paper aims to provide valuable genetic markers as tools with which to study the T. indicum population. In this study, a total of 143,998 microsatellite markers were developed based on the 2.61 × 106 microsatellites isolated from T. indicum genomic DNA sequences. Fifty selected microsatellite markers were amplified with varying numbers of alleles ranging from 0 to 19. Seven out of fifty microsatellite markers were characterized for polymorphism with the Hardy–Weinberg equilibrium (HWE) and linkage disequilibrium (LD) analysis. All seven microsatellite markers demonstrated a high polymorphic information content (PIC) value ranging from 0.87 to 0.93, with a mean value of 0.90. There is no evidence of scoring errors caused by stutter peaks, no large allele dropout, and no linkage disequilibrium among the seven loci; although loci Ti-Tr04, Ti-Tr09, Ti-Te04, Ti-Te13, and Ti-Pe5 showed signs of null alleles and deviation from the HWE due to excessive homozygosity. In conclusion, a significant amount of microsatellite markers was developed from the data set of next-generation sequencing, and seven of microsatellite markers were validated as informative genetic markers that can be utilized to study the T. indicum population. 相似文献
24.
Omid Khalifezadeh Koureh Mohammadreza Pourghayoumi Majid Majidian 《International Journal of Fruit Science》2019,19(1):1-12
The aim of this research was to determine the effect of three different fertilizing systems, including organic, conventional, and integrated ones, on the yield, fruit quality, antioxidant activity, and some phenolic compounds of white seedless grape. The study was carried out on several 6-year-old white seedless grapevine located in the Urmia Province (North-West Iran). The results showed that the fruit physical characteristics and yield were affected significantly by different fertilization systems. The highest yield was observed in the conventional fertilization, followed by organic and integrated systems. The leaf mineral contents were obviously dependent on the different fertilization used, whereas pH and titratable acidity were not affected. Based on our results, the highest values of antioxidant activity and total flavonoid were found in the organic and integrated fertilization systems, respectively. Also, the highest contents of total phenolic, catechin, and quercetin-3-galactoside were observed in the organic fertilization system. Overall, the highest nutritional quality and biochemical characteristics of white seedless grape were obtained in organic fertilization system, which improved antioxidant capacity by enhancing total phenolics, total flavonoids and valuable phenolic compounds. 相似文献
25.
Prakash Lakshmanan Majid Danesh Acram Taji 《The Journal of Horticultural Science and Biotechnology》2013,88(2):158-163
SummaryEfficient in vitro procedures for mass propagation of four commercially important Echinacea species have been deveoped. Plants of E. angustifolia, E. pallida, E. paradoxa and E. purpurea were regenerated by three methods, namely axillary bud proliferation, adventitious shoot formation and somatic embyrogenesis. Shoot tips obtained from in vitro germinated seedlings, adventitious shoots or somatic embryo-derived plantlets, when cultured on Murashige and Skoog medium enriched with 1 μM 6-benzylaminopurine, 2 μM kinetin, 0.5 μM indole-3-butyric acid and 4 mg–1 paclobutrazol multiplied three-fold within 3–4 weeks in culture. Incorporation of paclobutrazol in the shoot multiplication medium was necessary to recover healthy and robust shoots suitable for rooting. Direct, high-frequency shoot formation on intact leaves of shoots grown on 6-benzylaminopurine and kinetin-supplemented media, an unusual and novel observation made in this study, occurred in all the species studied. Rooting of in vitro developed shoots was achieved relatively easily with Murashige and Skoog basal medium rather than with auxin-enriched media. Culturing of hypocotyl explants on medium containing 3,6-dichloro-o-anisic acid (commonly known as dicamba), or 2,4-dichlorophenoxyacetic acid, resulted in direct somatic embryogenesis in all the species examined. The presence of cytokinin was required for somatic embryo germination, but further development of germinated somatic embryos into normal plantlets occurred in Murashige and Skoog medium. We conclude that the procedures described here could be used for rapid propagation as well as genetic transformation of commerically cultivated Echinacea species. 相似文献
26.
Masoud Selk Ghaffari DVM PhD Mehdi Marjani DVM PhD Majid Masoudifard DVM PhD 《Journal of Veterinary Cardiology》2009,11(1):67-69
A 3-year-old crossbreed male dog was presented with a history of blunt facial trauma. Skull radiographs showed right zygomatic arch fracture. An electrocardiogram revealed bradycardia, first-degree atrioventricular block and QT prolongation. Standard biochemical profile including electrolytes was normal. Atropine response test (0.04 mg/kg intravenously) restored normal sinus rhythm at a rate of 140 bpm with normal QT and PR intervals. This observation is consistent with oculocardiac reflex secondary to zygomatic arch fracture. 相似文献
27.
28.
A survey of ovine schistosomiasis was carried out in a Schistosoma bovis enzootic area in the central Sudan. Three hundred Desert sheep, representing different age groups, were screened for infection, using Pitchford's faecal egg counting technique. No infection was detected in animals under one year old, but from the age of 18 months onward, the prevalence increased progressively from around 20 per cent to 60 per cent in six-year-old sheep, and this was accompanied by an increase in infection intensity, as determined by faecal egg counts. These findings, which suggest that these sheep did not develop an effective resistance to schistosomiasis, contrasted with those previously recorded in cattle from the same locality, studied in the same year. 相似文献
29.
Molecular markers have been used for identification and mapping of genes and QTLs for numerous agriculturally important traits
in tomato, including resistance/tolerance to biotic and abiotic stresses and fruit- and flower-related characteristics. However,
the extent to which markers have been utilized in tomato breeding programs has not been clearly determined. A review of the
literature indicated that the utility of most markers for use in tomato breeding programs have not been verified. Many markers
are not validated across tomato genotypes or are not polymorphic within tomato breeding populations. In this study, we examined
the utility of available markers for several major disease resistance traits in tomato by testing them in a number of breeding
lines and commercial cultivars with known resistance/susceptibility responses. While several markers were validated, others
needed PCR optimization for successful amplifications or were not informative in the genotypes used. Specifically, of the
37 markers examined 19 (~51%) were informative, including markers for resistance to Fusarium wilt, late blight, bacterial
wilt, tomato mosaic virus, tomato spotted wilt virus, and root knot nematodes. It appears that many of the available markers
may need to be further refined or examined for trait association and presence of polymorphism in breeding lines and populations.
However, with recent advances in tomato sequencing, it is becoming increasingly possible to develop more informative markers
to accelerate the use of MAS in tomato breeding. 相似文献
30.
Hojjat-Allah Abbaszadeh Taki Tiraihi Ali Reza Delshad Majid Saghedi Zadeh Taher Taheri 《Iranian Biomedical Journal》2013,17(2):62-70
Background: The present study investigated the functional maturity of oligodendrocyte derived from rat bone marrow stromal cells (BMSC). Methods: The BMSC were isolated from female Sprague-Dawley rats and evaluated for different markers, such as fibronectin, CD106, CD90, Oct-4 and CD45. Transdifferentiation of OLC from BMSC was obtained by exposing the BMSC to DMSO and 1 µM all-trans-retinoic acid during the pre-induction stage and then induced by heregulin (HRG), platelet-derived growth factor AA (PDGFR-α), fibroblast growth factor and T3. The neuroprogenitor cells (NPC) were evaluated for nestin, neurofilament 68, neurofilament 160 and glial fibrillary acidic protein gene expression using immunocytochemistry. The OLC were assessed by immunocytochemistry for O4, oligo2, O1 and MBP marker and gene expression of PDGFR-α was examined by RT-PCR. Results: Our results showed that the fibronectin, CD106, CD90, CD45 and Oct-4 were expressed after the fourth passage. Also, the yield of OLC differentiation was about 71% when using the O1, O4 and oligo2 markers. Likewise, the expression of PDGFR-α in pre-oligodendrocytes was noticed, while MBP expression was detected in oligodendrocyte after 6 days of the induction. Conclusion: The conclusion of the study showed that BMSC can be induced to transdifferentiate into mature OLC. Key Words: Bone marrow stromal cell, Triiodothyronine, Platelet-derived growth factor α 相似文献