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41.
In order to be able to fertilize oocytes, human sperm must undergo a series of morphological and structural alterations, known as capacitation. It has been shown that the production of endogenous sperm reactive oxygen species (ROS) plays a key role in causing cells to undergo a massive acrosome reaction (AR). Astaxanthin (Asta), a photo-protective red pigment belonging to the carotenoid family, is recognized as having anti-oxidant, anti-cancer, anti-diabetic and anti-inflammatory properties and is present in many dietary supplements. This study evaluates the effect of Asta in a capacitating buffer which induces low ROS production and low percentages of acrosome-reacted cells (ARC). Sperm cells were incubated in the presence or absence of increasing concentrations of Asta or diamide (Diam) and analyzed for their ROS production, Tyr-phosphorylation (Tyr-P) pattern and percentages of ARC and non-viable cells (NVC). Results show that Asta ameliorated both sperm head Tyr-P and ARC values without affecting the ROS generation curve, whereas Diam succeeded in enhancing the Tyr-P level but only of the flagellum without increasing ARC values. It is suggested that Asta can be inserted in the membrane and therefore create capacitation-like membrane alteration which allow Tyr-P of the head. Once this has occurred, AR can take place and involves a higher numbers of cells.  相似文献   
42.

Background  

The general or spontaneous motor activity of animals is a useful parameter in chronobiology. Modified motion detectors can be used to monitor locomotor activity rhythms. We modified a commercial microwave-based detection device and validated the device by recording circadian and ultradian rhythms.  相似文献   
43.
Journal of Plant Diseases and Protection - A study was carried out for identification and detection of Phytophthora spp. from soil and plant samples, collected from Solanaceous crops in Egypt and...  相似文献   
44.
  1. The extent and intensity of impacts of multiple new dams in the Amazon basin on specific biological groups are potentially large, but still uncertain and need to be better understood.
  2. It is known that river disruption and regulation by dams may affect sediment supplies, river channel migration, floodplain dynamics, and, as a major adverse consequence, are likely to decrease or even suppress ecological connectivity among populations of aquatic organisms and organisms dependent upon seasonally flooded environments.
  3. This article complements our previous results by assessing the relationships between dams, our Dam Environmental Vulnerability Index (DEVI), and the biotic environments threatened by the effects of dams. Because of the cartographic representation of DEVI, it is a useful tool to compare the potential hydrophysical impacts of proposed dams in the Amazon basin with the spatial distribution of biological diversity. As the impact of Amazonian dams on the biota of both rivers and periodically flooded riparian environments is severe, DEVIs from different Amazonian tributary basins are contrasted with patterns of diversity and distribution of fish, flooded forest trees and bird species.
  4. There is a consistent relationship between higher DEVI values and the patterns of higher species richness and endemism in all three biological groups. An assessment of vulnerability at the scale of tributary basins, the assessment of biodiversity patterns related to DEVI, and the analysis of teleconnections at basin scale, demonstrate that recent construction of dams is affecting the biota of the Amazon basin.
  5. The evidence presented here predicts that, if currently planned dams are built without considering the balance between energy production and environmental conservation, their cumulative effects will increase drastically and represent a major threat to Amazonian biodiversity.
  相似文献   
45.
The mode of acquisition of gastric Helicobacter spp. infection in dogs has not been determined. It is suspected that oral-oral and faecal-oral transmission may be involved. The present study sought to determine if Helicobacter spp. DNA is present in the oral cavity of healthy and vomiting dogs. Thirty-eight pet dogs (27 vomiting and 11 clinically healthy) were studied. The presence of Helicobacter spp. was determined by single and nested PCR evaluation of DNA extracted from saliva, dental plaque and gastric biopsy samples. Helicobacter spp. DNA was detected by nested PCR in 36 (94.7%) gastric biopsies, 17 (44.7%) dental plaque and 19 (50%) saliva samples out of the 38 dogs examined. Overall 27 (71.1%) dogs screened by nested PCR were found to harbour Helicobacter spp. DNA in the oral cavity (dental plaque and/or saliva). There was no significant difference in the prevalence of Helicobacter spp. DNA in the oral cavity of vomiting and healthy dogs, and the time from vomiting to oral sampling did not have significant impact. This study confirms the high prevalence of gastric Helicobacter spp. infection in dogs, and reveals that Helicobacter spp. DNA is detectable in the oral cavity of over 70% of dogs. These findings support the possibility of oral-oral transmission between dogs and that the canine oral cavity may act as source of non-pylori Helicobacter spp. infection for humans.  相似文献   
46.
Abstract This study was undertaken to determine the effect of salinity and pH on tolerance to low dissolved oxygen concentration in postlarval (PL 12; 18 mg wet weight) and early juvenile (720 mg wet weight) Peneaus setiferus . Lethal levels of dissolved oxygen were determined in animals at four combinations of salinity and pH (36 and 15 ppt salinity and pH 6 and 8). For postlarvae, the 48-h LC50 for dissolved oxygen was 1.27 mgO2/L at 15 ppt and pH8, and was significantly lower than that obtained in the other combinations of salinity and pH (P < 0.05). For juveniles, the 72-h LC50 was 1.16 mg1L at 15 ppt and pH 8, and was significantly lower than that obtained in the other combinations of salinity and pH (P < 0.05). A significant interaction between salinity and pH was observed. These results suggest that the intensive culture of P. setiferus may be conducted at moderate salinity, where shrimp appear to be more tolerant of low concentrations of oxygen than at higher salinities.  相似文献   
47.
Olive oil has been characterized by rapid proton transfer reaction-mass spectrometry (PTR-MS) headspace analysis without any concentration of the volatiles or pretreatment of the samples. Comparison of extra virgin and defective (rancid) samples, as described by a panel of sensory judges, and the monitoring of thermo-oxidation processes are discussed. Multivariate analysis of PTR-MS data has been carried out and cross-validated, providing (i) reliable classification models for extra virgin oil as opposed to defective oil and (ii) calibration models able to predict independently thermo-oxidative degradation and the corresponding peroxide value. PTR-MS fragmentation patterns of volatiles considered in this study are also reported.  相似文献   
48.
Model wheat doughs started with six different lactic acid bacteria (LAB), with or without a commercial baker's yeast culture, were used to study proteolysis in sourdough fermentations. Cell counts, pH, and free amino acid concentration were measured. Sequential extraction of dough samples was performed to separate wheat proteins. The salt-soluble protein fraction (albumins and globulins) was analyzed by RP-HPLC and SDS-PAGE, whereas propanol-soluble (gliadins) and insoluble (glutenins) protein fractions were analyzed by SDS-PAGE only. Multivariate statistical methods were used for the analysis of results. The presence of yeasts and LAB affected RP-HPLC and SDS-PAGE patterns of the salt-soluble fraction in a complex way. The only changes in the gluten proteins that could be related to the presence of LAB were the appearance of new protein fragments (20 and 27 kDa) from gliadins and the degradation of high molecular weight glutenin subunits.  相似文献   
49.
Sirex noctilio is one of the most important invasive pests that affect Pinus radiata plantations in Chile. Its management is based on a biological control complex, the most important component of which is the nematode, Deladenus siricidicola. However, in some areas, S. noctilio populations attain epidemic levels and no effective control methods exist to reduce large populations in a short period. In this study, we evaluated a novel method called mega-trap-plots (MTPs), which consist of an area of 1 ha with trap trees, which were debilitated in four different months (from November to February) with the purpose of reducing the Sirex wasp population through harvesting of trees attacked. The main objective was to reduce the potential population of S. noctilio, by evaluating four periods or months of MTP installation to maximise the colonisation of trap trees by wood wasps. The results showed that the MTPs that were installed from November to January had the highest wood wasp infestation, which was coincident with the flight period of the insect. The trap trees were clearly attractive to S. noctilio females up to 90 d following their establishment. The MTPs that were established in November concentrated a potential population of 57 901 females of S. noctilio, which represents a population 5.4 times greater than that in the control, with 10 701 females. The population of S. noctilio attracted between November and January shows that the use of MTPs is an effective system for the management of wood wasps on plantations with a high level of infestation and thereby can reduce their spread and the attack of new trees within the same forest compartments.  相似文献   
50.
Changes in anthocyanins during ripening of Cabernet Sauvignon and Tempranillo grapes were studied over a three year period. The accumulation of anthocyanins showed variations during ripening, especially during the first three weeks after veraison, and the accumulation pattern of those molecules changed only slightly from one year to another. On the other hand, the percentages of the different anthocyanins studied were different for each cultivar, and some changes were observed in both cultivars depending on the weather conditions of the growing season. In warm years the percentages of primitive anthocyanins (delphinidin 3-O-glucoside and petunidin 3-O-glucoside) were slightly lower than in a relatively cool year. Nevertheless, the anthocyanin fingerprints of Cabernet Sauvignon and Tempranillo grapes seem to be rather stable during ripening, despite the sugar content of the grapes.  相似文献   
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