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11.
The aim of this study was to investigate the role of Nitric Oxide (NO) in the atresia of ovarian follicles in an animal model. Twenty adult, female rats (90 days old with body weights of210 +/- 10 g in the beginning of the experiments) were divided into 4 groups of 5 each. They were treated twice daily from the subcutaneous route for 21 successive days with either of the following chemicals: nitroglycerine, L-arginine, L-NAME, or saline. On day 22, all animals were sacrificed. Ovaries were dissected out free of connected tissue and were fixed in formaline 10%. Later, paraffine blocks were prepared and serial sections were made by means of H and E routine staining method. Intact and atretic follicles were counted separately. In addition, damages were analyzed qualitatively from the points of view of appearance and morphologic changes. In the evaluation of ovarian follicular structures, different types of healthy as well as atretic follicles were observed. In most of atretic follicles, the oocytes were abnormally elongated and increnation of their outlines were obvious. There were numerous macrophages around and inside of the atretic follicles. Our investigation regarding the distribution of atretic follicles in the ovaries of test groups revealed that atretic follicles in the L-NAME treated group were increased in comparison to the control group. Conversely, however, in the arginine-treated group, the atretic follicles were reduced compared to the control animals. Treatment with nitroglycerine of the rats decreased the number of atretic follicles significantly (p < 0.05) in comparison to the control group. In conclusion, enhanced NO, either from endogenous or exogenous origins, prevents atresia phenomenon, while inhibition of NO exerts an opposite effect.  相似文献   
12.
There is general believe that exercise may results in changes that likely reduce the risk of developing cardiovascular disease and may slow the progression of established coronary artery disease. Chronic cardiovascular training results in changes in lipoproteins and apolipoproteins that reflect adaptation to the increased metabolic demands imposed by frequent, vigorous exercise. Moreover, the alterations in lipoproteins vary according to level of physical conditioning and intensity of exercise. One hundred three pre-menopausal physically active women ages 20-50 years old which have been exercising for at least 6 months involve in this study. Upon entering the study subjects were asked to complete questionnaire, regarding personal health and diet history (24 h recall plus 7 days food frequency list). Total calorie intake, level of carbohydrate, protein and fat in the subjects' diet were analyzed. In addition the concentration of women's plasma triglycerides, total cholesterol, LDL-C and HDL-C were also measured and compared with normal value. The results of the present study showed that, the mean total caloric intake of women were 1812.54 kilocalories, where their carbohydrate, protein and fat intake were 67.28, 12.83 and 19.89% of their total calories, respectively. The average age, weight, height and Body Mass Index (BMI) of the women involved in the study were, 30.81+/-8.87 years, 57.85+/-7.79 kg, 160.32+/-5.36 cm and 22.53+/-2.82 kg m(-2), respectively. Plasma lipid and lipoprotein concentration of women were also in normal range with the lowest in those who exercise for more than one year and physical education teacher.  相似文献   
13.
Turfgrasses are commonly propagated by seeds. In some genera of turfgrasses, the presence of low germination percentage (GP) or rate is the main problem in seed propagation. The present investigation was undertaken to determine the best concentration and duration of sulphuric acid treatment for seeds of the following turfgrass genera: Cynodon dactylon [L.] Pers.; Festuca rubra L. var. rubra‘Shadow’; Lolium perenne L. ‘Barball’ and Poa pratensis L. ‘Merion’. In the first experiment, sulphuric acid was used with concentrations of 0 (control), 25, 50, 75 and 100 % for 10, 15, 20, 25 and 30 min. In the second experiment, effects of light/dark (16/8) or dark conditions on germination rates of different mentioned genera were investigated using the best specific acid treatments. Each treatment was replicated four times with 100 seeds per replicate kept in plastic Petri dishes. The results indicated that in Cynodon, using 50 % acid for 20–25 min had highest GP and mean daily germination (MDG) in light/dark; in Festuca, using 25 % acid for 15 min had highest GP and MDG in light/dark; in Lolium using 50 % acid for 10 min had highest MDG in dark and in Poa, using 50 % acid for 15–25 min had highest MDG in dark. Both Cynodon and Poa had the highest and Festuca had the lowest GPs. Cynodon and Festuca had the highest and lowest MDGs, respectively. This simple procedure, with considerable results, may be replaced to time-consuming and expensive methods such as seed priming.  相似文献   
14.
The essential oil of Oliveria decumbens was investigated for its components and antimicrobial activity against six bacteria and two fungal strains. The essential oil was characterized by a high amount of oxygenated monoterpene components of which thymol (47.06%) and carvacrol (23.31%) were the major components. The oil exhibited high antimicrobial activity against all tested Gram+ and Gram- bacteria and fungal strains.  相似文献   
15.
The genetic diversity among 128 Iranian Rosa persica (R. persica) accessions in the different populations was analyzed. Amplified fragment length polymorphisms (AFLP) technique was used to produce 171 polymorphic fragments. The number of polymorphic loci ranged from 101 to 147 and the polymorphism information content (PIC) varied from 0.289 to 0.073, with an average of 0.16. This shows extreme variability and genetic diversity among the studied R. persica populations. An indirect estimate of the number of migrants per generation (Nm = 0.376) indicated that gene flow was relatively low among populations of the species. Cluster analysis using the UPGMA method grouped all accessions into six clusters. The results did not show relative agreement with the genotypes’ region of origin. Based on an analysis of molecular variance, 48% of the genetic variation of R. persica was within population and 52% was among populations. The present analysis revealed that Iranian R. persica genotypes are highly variable and genetically distinct from their origins. The apparent unique nature of the R. persica genotypes revealed by our results supports the case for the implementation of more intense characterization and conservation strategies, and provides useful information to address breeding programmes and germplasm resource management in Rosa spp.  相似文献   
16.
17.
Tea [Camellia sinensis (L.) O. Kuntze] is a highly phosphorus (P) deficiency-tolerant species, however, involving mechanisms have not been investigated so far. In this work, mechanisms for intrinsic efficiency of P utilization were studied in tea seedlings grown hydroponically without or with adequate P supply. The contribution of P reserve in cotyledons to the P nutrition of tea seedlings and the role of mature leaves were examined at two contrasting P supply levels in plants with intact or severed cotyledons. During three subsequent harvest intervals, distinct reduction of P content was observed not only in cotyledons, but also in the mature leaves, stem and roots of plants supplied with low P. In plants supplied adequately with P, in contrast, a continuous rise of P content was detected. It was concluded that the cotyledons of tea plants are a major source of P but not organic compounds for growth of the young seedlings.  相似文献   
18.
This research was conducted to investigate the effect of natural zeolite on vegetative growth and flower characteristics of tuberose (Polianthes tuberosa L.). The experiment was performed as a completely randomized design with seven treatments (5, 10, 15, 20, 25 and 30 g zeolite/kg soil mixture along with control) and four replicates. Results indicate that zeolite increased the height of flowering stem, diameter of flower, leaf area and chlorophyll content, but decreased the diameter of flowering stem, dry weight of shoots, and roots and bulblets. Overall, zeolite added to the soil mixture had beneficial effects on only some of the parameters of tuberose growth and development.  相似文献   
19.
The destruction of natural ecosystems is an important issue in many parts of the world. In the west of Iran, a vast area of the Zagros Mountain range is covered by typical vegetation including several rare plant species, of which many are currently considered endangered by anthropogenic activities. Despite the important role of soil seed banks to help conserve these degraded plant communities, the floristic studies in the Zagros forests have only focused on above- ground vegetation. In this study, the characteristics of soil seed banks and above-ground vegetation were examined at two forest sites: an undisturbed control (Un) and a disturbed (D) site. The objectives of this study were 1) to investigate the diversity of above-ground vegetation and soil seed banks in disturbed and undisturbed forests, 2) to examine the soil properties and the germination characteristics of the soil seed bank in disturbed and undisturbed oak forests and 3) to estimate the potential of soil seed banks in the restoration of disturbed sites. The results show that soil properties between Un and D sites were significantly different with higher values of pH, NH4-N, N~o,, CEC, OC, clay and canopy percentage in the Un site than in the D site. The Simpson diversity, Margalef richness and evenness indices differed significantly between sites, either for the soil seed banks or the above-ground vegetation. After a period of 26 weeks, the germination speed and the mean daily number of germinants were significantly different between Un and D sites. Without other conservation measures, soil seed banks alone cannot result in a full recovery after severe disturbances in the oak forests of Zagros.  相似文献   
20.
Landscapes are considered to be complex systems that are hierarchically structured and spatially scale-dependent. Geopedology allows a systematic approach in geomorphic analysis for soil mapping that extrapolates the results obtained at sample areas up to similar units. This paper examines the influence of sampling intervals on the accuracy of geopedological results in the Borujen region, Central Iran. After a primary interpretation of the study area on air photos (1:20 000), a geomorphic unit that encompassed the maximum surface of the sample area (and also the study area) was selected and was surveyed at three different scales: 500, 250 and 125 m intervals. The credibility of generalization of the results of the geopedological approach for the studied unit was tested by comparison with three profiles in a similar unit outside the sample area, named the validation area. Although the type of mapping unit in the sample area and the validation area was the same (complex) at the three different scales, the dominant soil in the validation area was different in comparison with the sample area at 125 and 250 m intervals. The results indicate that the geopedological approach to soil mapping is better carried out in reconnaissance or exploratory surveys. Comparison of soil types between the unit in the sample area and the validation area at three scales indicated that by increasing the taxonomic accuracy, the hidden aspects of the soils may be more identifiable. Therefore, although the geopedological approach tries to distinguish more homogeneous soil mapping units, it still is not able to fully define and represent the variability and apparent chaotic nature of the soils. We recommend further investigations on different techniques of stratifying the landscape in order to better analyze and understand the soil forming processes and soil variability and to improve sampling and mapping approaches.  相似文献   
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