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81.
An infestation of mangrove forests with Neodolichodorus persiangulfus n. sp. in southern Iran is reported. This paper is the first to report a representative species of the genus in the country. The new species was characterized by 2,120 (1795–2400) µm long females, and 1755 (1533–2019) µm long males, a continuous to slightly offset cephalic region separated from the rest of the body by a shallow depression, having 5–7 annuli and a distinct labial plate, a lateral field with four lines, the outer ones crenate, irregularly areolated in anterior and posterior body region, 79 (66–85) μm long female stylet, a didelphic‐amphidelphic female reproductive system with asymmetric sclerotized vaginae, phasmids 5–10 annuli behind the anus, female tail elongate conoid, suddenly narrowing at 5–12 annuli posterior to anus and males with trilobed bursa, 52.5 (47–58) μm long spicules and 21.5 (18–27) μm gubernaculum. With the elongate‐conoid female tail and c? >1.2, the new species is close to five known species of the genus: N. brevistylus, N. leiocephalus, N. paralongicaudatus, N. rageshi and N. sinensis, but is distinguished from them by the morphology of the female tail, areolation type of the lateral field, position of hemizonid and phasmid and morphometric data. Molecular phylogenetic analyses using sequences of the near full‐length fragment of the small and the D2‐D3 expansion segments of the large subunit ribosomal DNA (SSU and LSU rDNA D2‐D3) revealed the new species placed in a clade including one isolate of Neodolichodorus sp. and some species of Globodera, Heterodera and Rotylenchulus with 0.89 Bayesian posterior probability (BPP) in SSU phylogeny. The only available SSU sequence of the genus was the tentative closest relative to the new species in the inferred SSU tree. In the reconstructed LSU phylogenetic tree, N. persiangulfus n. sp. formed a poorly supported clade with Rotylenchulus spp. in Bayesian inference (BI), and the only other available D2‐D3 sequence of the genus occupied a distant placement to the new species.  相似文献   
82.
The possible role of chitinase in in vitro growth inhibition of the wheat pathogens Fusarium graminearum and Bipolaris sorokiniana by Bacillus pumilus SG2 was investigated. B. pumilus SG2, a chitinolytic bacterium producing two different chitinases, was previously isolated from the saline deserts of Iran. When grown in Spizizen salts medium with colloidal chitin, B. pumilus SG2 secreted two chitinases into the medium, resulting in growth inhibition of F. graminearum and abortion of hyphal elongation of B. sorokiniana. In contrast, when glucose was used as the carbon source, the chitinases were not expressed and antifungal activity of the B. pumilus SG2 was completely abolished. These results confirmed that expression of the B. pumilus SG2 chitinases is under the control of two types of regulation, special regulation by chitin and global regulation by glucose. We demonstrated that chitinases are the main components that caused hyphal inhibition activity of B. pumilus SG2. Hyphal inhibition of F. graminearum and B. sorokiniana was stable in agar for a minimum of 14 days.  相似文献   
83.
Nitrification inhibitors can effectively decrease nitrification rates and nitrous oxide(N2O)emission while increasing crop yield under certain conditions.However,there is no information available on the effects of nitrification inhibitors and tillage practices on N2O emissions from maize cropping in Iran.To study how tillage practices and nitrapyrin(a nitrification inhibitor)affect N2O emission,a split factorial experiment using a completely randomized block design with three replications was carried out in Northeast Iran,which has a cold semiarid climate.Two main plots were created with conventional tillage and minimum tillage levels,and two nitrogen(N)fertilizer(urea)management systems(with and without nitrapyrin application)were created as subplots.Tillage level did not have any significant effect on soil ammonium(NH4+)and nitrate(NO3-)concentrations,cumulative amount and yield-scaled N2O emission,and aboveground biomass of maize,whereas nitrapyrin application showed significant effect.Nitrapyrin application significantly reduced the cumulative amount of N2O emission by 41%and 32%in conventional tillage and minimum tillage practices,respectively.A reduction in soil NO3-concentration by nitrapyrin was also observed.The average yield-scaled N2O emission was 13.6 g N2O-N kg-1N uptake in both tillage systems without nitrapyrin application and was significantly reduced to 7.9 and 8.2 g N2O-N kg-1N uptake upon the application of nitrapyrin in minimum tillage and conventional tillage practices,respectively.Additionally,nitrapyrin application increased maize biomass yield by 4%and 13%in the minimum tillage and conventional tillage systems,respectively.Our results indicate that nitrapyrin has a potential role in reducing N2O emission from agricultural systems where urea fertilizers are broadcasted,which is common in Iran due to the practice of traditional farming.  相似文献   
84.

Asparagus officinalis is the most economically important species of asparagus worldwide. Commercial cultivars of asparagus are susceptible to some biotic and abiotic stresses. Drought stress is one of the most common stresses in agricultural crops cultivation. The main purpose of the current study was to compare Iranian asparagus accessions drought tolerance rate with that of ‘Mary Washington’ commercial cultivar and introducing superior accessions in terms of dry resistance rate. A factorial experiment was laid out based on a completely randomized design with three replications. The factors were a) asparagus accession in 10 levels including nine wild accessions of Iranian asparagus and ‘Mary Washington’ commercial cultivar (as control) and b) drought stress in four levels including 0 (as control), 5, 10 and 15% (w/v polyethylene glycol). Results showed that highest values of percentage and speed of seed germination and lengths of radicle and plumule were recorded in Gazanak accession. The lowest values of radicle length were recorded in Chalaki and Shiraz accessions (6.19 and 8.01?mm, respectively). Calli of ‘Mary Washington’ cultivar under highest applied level of drought stress showed the lowest value of relative growth rate (11.53?mg/day). Cluster analysis based on assessed characteristics under different applied levels of drought stress, divided Iranian asparagus accessions into four groups at Euclidean distance of 2.0. In conclusion, obtained results showed that Iranian asparagus accessions especially Gazanak accession could be a good candidate to apply in asparagus breeding programs with aim of producing asparagus dry tolerant cultivars.

  相似文献   
85.
This is the first report of an acephalous lamb from the transfer of an in vitro-produced sheep embryo. Twelve in vitro-fertilized embryos were transferred to 4 recipient ewes (3 embryos/ewe). Two ewes remained pregnant: one delivered a normal female lamb, the other a male acephalous lamb. Possible contributing factors are discussed.  相似文献   
86.
87.
BACKGROUND: Teucrium polium is an analgesic, antidiabetic and antilipeidemic herbal medicament. The aim of this survey was to evaluate the effect of aqueous extract T. polium on liver enzymes linked to liver dysfunction, serum lipids and glucose, in diabetic male rats. METHODS: A total of 20 Sprague-Dawly male rats became diabetic by intraperitoneal injection of streptozotocin (60 mg/kg). the animals were divided randomly into two groups. Experimental group was fed Teucrium polium (50 mg/kg) for a month but control group was received the same volume of distilled water. Liver enzymes, biochemical parameters (cholesterol, triglyceride, low density lipoprotein, alanine transaminase, aspartae transaminase) and glucose were measured by kinetic (Enzymatic) and colorimetric methods. Data obtained were analyzed and mean values were compared by paired student's t-test. The results were expressed as mean +/- SD. Significant differences were set at P < 0.05. RESULTS: Our results showed that in test group, serum glucose values decreased significantly (P < 0.05), but cholesterol, triglyceride, low density lipoprotein, alanine transaminase and aspartae transaminase increased significantly after use of T. polium (P < 0.05). This parameters value did not show any changes in control group. CONCLUSION: Although the aqueous extract of Teucrium polium has strong hypoglycemic properties in experimental animals, but because of some hepatotoxic effects, it is not suitable to use it in human as an antidiabetic agent.  相似文献   
88.
The properties of soils affected by salinity and processes involving degradation of soil structure have been partly recognized. However, the effects of saline and sodic conditions on mechanical and physical properties of soils have been studied to a lesser extent. In this research, the effects of electrical conductivity (EC) and sodium adsorption ratio (SAR) on soils possessing various amounts of organic matter were assessed under laboratory conditions. The soils contained a uniform clay type, predominantly Illite. The major difference of the soils was their amount of organic matter content. The treatments consisted of solutions with definite EC and SAR (two levels of EC: 0.5 and 4 dS/m and three levels of SAR: 0, 5 and 15). The amount of tensile strength was dependent on organic matter, EC, and SAR in a way that with the increase of SAR, the tensile strength decreased. In similar SAR, treatments with higher EC exhibited greater tensile strength. Also, the soils with higher organic matter showed greater tensile strength. The analysis of variance showed the significant difference (at 1%) between the mean of parameters analyzed (soil type, sampling depth, EC, and SAR). The order of averages of tensile strength were: permanent pasture (Agropyron elengatum)Festuca arusdinaceae)相似文献   
89.
90.
An eight‐week research was conducted to investigate the effects of single or combined administration of sodium propionate (Na‐P) and sodium acetate (Na‐A) on the performance of yellowfin seabream (Acanthopagrus latus) juveniles (6.5 ± 0.3 g). A plant protein (PP)‐rich diet was supplemented with sole or blends of organic acid salts (OAS) namely Na‐P and Na‐A to design six experimental feeds including control (without OAS), Na‐P5 (5 g/kg Na‐P), Na‐P10 (10 g/kg Na‐P), Na‐A5 (5 g/kg Na‐A), Na‐A10 (10 g/kg Na‐A) and Na‐P + A (5 g/kg Na‐P + 5 g/kg Na‐A). Except for Na‐A5 group, the other OAS‐supplemented treatments had higher growth and feed efficiency ratio than the control (p < .05). The inclusion of OAS in the experimental feeds pronouncedly enhanced plasma lysozyme and alternative complement pathway activities compared to the control. Furthermore, fish fed on the OAS‐supplemented diets had greater catalase and glutathione peroxidase activities in the liver than the control (p < .05). Total antioxidant capacity in the liver of fish fed on the OAS‐supplemented diet also was higher than the control. Fish fed on the OAS‐supplemented diets had higher pepsin, trypsin and lipase activities than the control. The insulin‐like growth factor 1 (IGF‐1) gene expression was remarkably down‐regulated in the liver of fish fed on the OAS‐supplemented diets compared to the control especially in groups fed on the Na‐P10 and Na‐A10 diets. The greatest IGF‐1 gene down‐regulation level in the gut was in fish fed on the Na‐P5 and Na‐P10 diets. The interleukine‐1β in the gut was remarkably up‐regulated in the control compared to the other groups (p < .05). The lactic acid bacterial colonies count in the gut of the control was lower than the OAS‐supplemented groups. Based on the findings of the present study, supplementing PP‐rich diets with 10 g/kg Na‐P or blends of Na‐P (5 g/kg) and Na‐A (5 g/kg) beneficially alleviated inflammatory responses and improved immune parameters and digestive capacity in yellowfin seabream juveniles.  相似文献   
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