首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   95篇
  免费   8篇
林业   2篇
农学   4篇
  23篇
综合类   6篇
农作物   10篇
水产渔业   22篇
畜牧兽医   28篇
植物保护   8篇
  2021年   1篇
  2020年   2篇
  2018年   6篇
  2017年   2篇
  2016年   1篇
  2015年   5篇
  2014年   1篇
  2013年   10篇
  2012年   1篇
  2011年   7篇
  2010年   3篇
  2009年   4篇
  2008年   3篇
  2007年   7篇
  2006年   5篇
  2005年   1篇
  2004年   3篇
  2003年   4篇
  2002年   4篇
  2001年   3篇
  2000年   1篇
  1999年   8篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1989年   1篇
  1987年   5篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1980年   1篇
  1974年   1篇
  1968年   2篇
排序方式: 共有103条查询结果,搜索用时 15 毫秒
91.
92.
Kupffer cells from the liver and erythrocytes from peripheral blood were collected at the post-patent period from albino rats infected earlier with Plasmodium berghei and rhesus monkeys infected earlier with P. cynomolgi var. bastianelli or P. knowlesi. The cells were subinoculated into individual normal recipients. These recipients subsequently showed parasitaemia in their circulation. The parasites present in Kupffer cell preparations were found to be sensitive to trypsin treatment, while those in erythrocytes were found to be resistant to trypsin treatment. This differential sensitivity of parasites to trypsin was observed in all the three species of plasmodia studied so far.  相似文献   
93.
Germination, seedling growth, concentrations of photosynthetic pigments and nutrient uptake inTriticum vulgare L. (Var. W-H-147) were studied in response to sugarmill effluent application (10% concentration) in aqueous Vs. soil medium. The effluent rich in various nutrients showed particularly high concentration of sodium. Germination was not affected by the effluent treatment. Seedling growth was reduced significantly by the effluent in aqueous medium, but not in soil. The effluent treatment increased the concentrations of various pigments, however, the pigment ratios got changed in the aqueous medium only. The uptake of nitrogen, magnesium and carbon by the seedlings decreased while that of calcium, sodium and phosphorus increased in effluent treated plants, the changes being more marked in aqueous medium except for phosphorus. In the effluent treated plants, uptake of potassium and chloride increased in aqueous medium, hut decreased sharply in soil.  相似文献   
94.
95.
In vitro biodegradation of trifloxystrobin (TFS) under darkness could best be explained by two-compartment first + first-order rate kinetics with half-lives ranging between 1.8 and 2.3 days. Hydrolysis was found to be the major pathway of degradation resulting in the formation of the acid metabolite, TFS-acid, with an EE conformation. The adsorption rate kinetics of both TFS and TFS-acid followed linear and Freundlich isotherms. The extent of adsorption was directly correlated with organic matter and clay contents, whereas desorption had a negative correlation. The high partition coefficients (KD) indicate strong adsorption of TFS on all of the test soils without any appreciable risk of groundwater contamination. In case of the TFS-acid, however, the adsorption was weaker; hence, if its further degradation is slow, it may contaminate lower soil horizons under worst case conditions. TFS did not cause any adverse effect on the soil microbial population. TFS was susceptible to aquatic photolysis in summer with an environmental half-life of 0.7-1.3 days irrespective of the latitudes.  相似文献   
96.
Two Azospirillum brasilense strains, CDJA and A40, capable of growing and producing plant growth-promoting (PGP) substances at the sub-optimal temperature (SOT) of 22°C, were tested for their ability to survive, colonize and enhance wheat growth and yield under field conditions upon inoculation. The response was compared with that of A. brasilense strain, A9, impaired in growth and PGP activities at SOT (22°C) but otherwise comparable to CDJA and A40 at 37°C. A field experiment was carried out in a split-plot design with four levels of N as main plots and three strains and an uninoculated control as subplots. A differential response in the establishment of the strains and in plant growth and yield was obtained, due to the categories of strains, particularly at lower levels of N (0 kg and 40 kg N ha-1). The results clearly demonstrated that strains capable of growing and producing PGP substances at SOT are better inocula for wheat.  相似文献   
97.
Plant disease resistance gene analogue polymorphism (RGAP) in tomato has been studied on the basis of NBS–LRR (Nucleotide Binding Site–Leucine Rich Repeat) class of genes using degenerated primers. Results revealed variable degree of polymorphism of the Group II compared to the Group I class of R genes. The probable explanation could be further diversification of the Group II class within tomato genotypes compared to the Group I class, which is relatively conserved. Furthermore, investigation of the diversity of the I2 class of genes, responsible for resistance to Fusarium oxysporum f.sp. lycopersici, revealed that genomic PCR mediated identification of functional I2 using the specific primers designed from the conserved domain of LRR region of I2 class of genes, is not possible on the basis of amplified fragment size. On the contrary, PCR amplification of 249 bp fragment from the conserved LRR region of I2 homologue I2C1/C2 gene from all the resistant lines indicated co-segregation of I2C1/C2 to the susceptible background along with the I2 gene during introgression. This may be an indirect PCR-mediated approach for marker-assisted breeding of functional allele of I2.  相似文献   
98.
Antibody diversification in IgM and IgG antibodies was analyzed in an 18-month old bovine (Bos taurus) suffering from naturally occurring chronic and recurrent infections due to bovine leukocyte adhesion deficiency (BLAD). The BLAD, involving impaired leukocyte β2 integrin expression on leukocytes, develops due to a single point mutation in conserved region of the CD18 gene resulting in substitution of aspartic acid128 with glycine (D128G). Twenty four VDJCμ and 25 VDJCγ recombinations from randomly constructed cDNA libraries, originating from peripheral blood lymphocytes, were examined for the variable-region structural characteristics in IgM and IgG antibody isotypes. These analyses led to conclude that: (a) expression of exceptionally long CDR3H is isotype restricted to cattle IgM antibody; (b) VDJ recombinations encoding IgM with exceptionally long CDR3H undergo clonal selection and affinity maturation via somatic mutations similar to conventional antibodies; (c) somatic mutations contribute significantly to both IgM and IgG antibody diversification but significant differences exist in the patterns of ‘hot spot’ in the FR1, FR3 and CDR1H and, also, position-dependant amino acid diversity; and (d) transition nucleotide substitutions predominate over transversions in both VDJCμ and VDJCγ recombinations consistent with the evolutionary conservation of somatic mutation machinery. Overall, these studies suggest that both somatic mutations and exceptional CDR3H size generation contribute to IgM and IgG antibody diversification in cattle during the development of immune response to naturally occurring chronic and multiple microbial infections.  相似文献   
99.
The present study evaluated the effect of supplementation of retinol in the vitrification solution on the viability, apoptosis and development-related gene expression in vitrified buffalo preantral follicles. Preantral follicles isolated from cortical slices of ovaries were randomly assigned into three groups: Group1—Control fresh preantral follicles; Group 2—Vitrification treatment (Vitrification solution 1 (VS1) –TCM-199 + 25 mM HEPES + Foetal bovine serum (FBS) 10%, Ethylene glycol (EG): 10%, Dimethyl sulphoxide (DMSO): 10%, Sucrose-0.3 M for 4 min; VS2- TCM-199 + 25 mM HEPES + FBS10%, EG:25%, DMSO: 25%, Sucrose:0.3 M for 45 s); Group3—vitrification treatment +5 μM of Retinol. Preantral follicles were placed in corresponding vitrification medium and plunged into liquid nitrogen (−196°C). After a week, the follicles were thawed and analysed for follicular viability and gene expression. There was no significant difference in the viability rates among the Group 1(Fresh preantral follicles) (91.46 ± 2.39%), Group 2 (89.59 ± 2.46%) and Group 3 (87.19 ± 4.05%). There was a significantly (p < .05) higher mRNA expression of BCL2L1, GDF-9 and BMP-15 in the vitrification + retinol group compared with the control group. There was a significantly (p < .05) higher expression of Caspase-3 and Annexin-5 in the vitrification group and Vitrification + retinol group compared with control group of follicles. It is concluded that the supplementation of 5 μM of Retinol in Vitrification solution was an efficient vitrification procedure for the vitrification of buffalo preantral follicles.  相似文献   
100.
Field experiments were conducted in oil and edible sunflower to study the effects of potassium(K) fertilization on achene yield and quality, and to estimate the nutrient internal efficiency(IE) and nutrient requirement in sunflower production. All trials in edible sunflower and 75% trials in oil sunflower showed positive yield responses to K fertilization. Compared with control without K fertilization, the application of K increased achene yield by an average of 406 kg ha~(–1) for oil sunflower and 294 kg ha~(–1) for edible sunflower. K application also increased 1 000-achene weight and kernel rate of both oil and edible sunflower. K fertilization improved the contents of oil, oleic acid, linoleic acid and linolenic acid in achenes of oil sunflower, and increased contents of oil, total unsaturated fatty acid and protein in achenes of edible sunflower. The average agronomic efficiency of K fertilizer was 4.0 for oil sunflower and 3.0 kg achene kg~(–1) K_2O for edible sunflower. The average IE of N, P and K under balanced NPK fertilization was 22.9, 82.8, and 9.9 kg kg~(–1) for oil sunflower, and 27.3, 138.9, and 14.3 kg kg~(–1) for edible sunflower. These values were equivalent to 45.5, 14.1, and 108.1 kg, and 39.0, 8.0, and 71.7 kg of N, P and K, respectively, in above-ground dry matter required for production per ton of achenes. The average harvest index of N, P and K was 0.47, 0.56 and 0.05 kg kg~(–1) in oil sunflower, and 0.58, 0.58 and 0.14 kg kg~(–1) in edible sunflower.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号