首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Untilnow,allmachiningmethodsusedarephysicalorchemicalorphysicochemical.Thetechnologysystemofnaturalsciencecanbeclassifiedintothefollowingthreesubsidiarysystems:physics,chemistryandbiology.Thereforeabiologicalmachiningtechnologywillbeabrandnewbranchinma…  相似文献   

2.
持续农业与中国的生态农业   总被引:6,自引:0,他引:6  
持续农业与中国的生态农业李萍萍,章熙谷(南京农业大学农学系,210014)SustainableAgricultureandChina’sEcologicalAgriculture¥.LiPingping;ZhangXigu(NanjingAgricul-turalUniversity,210014).ChineseJournaJofEcolegy,1993,12(2):16-18.Thebackground,conceptandcharacteristicsofsustainableagriculturearediscussed,anditssimilaritiesanddifferencestoChina’secologicalagriculturearedescribed.It’sconsideredthatChina’secologicalagri-cultureisaconcretereflectionofsustainableagricultureandasuccessfulmodelforagriculturaldevelop-ment.Keywords:sustainableagricult  相似文献   

3.
Proteincrystalgrowthhasbeenofgreatimportanceinexploitationofstructuresofbiologicalmacromolecules.Themicrogravityenvironmentinspaceisanidealplacetostudythecomplicatedproteincrystallizationprocessandtogrowgoodqualityproteincrystals.Sincethe1980s,noticeabl…  相似文献   

4.
Receptor,theprimarysiteofcellperceivingexternalsignals,controlsthecommunicationbetweencellsandenvironment[1].Acetylcholineisanimportantneurotransmitterinvolvedinthetransmissionofsignalsatjunctionsbetweennervesandbetweennerveandmuscle.Theactionofacetylch…  相似文献   

5.
Breeding technology of alloplasmic wheat   总被引:4,自引:0,他引:4  
Thenucleiofcultivatedwheatcouldbetransferredintocytoplasmofheterogenicspeciesorgeneraviasubstitutionbackcrossandothertechniques,thusTriticinaeexhibitswidegeneticdiversityofcytoplasm.Thisdiversityhadboththeoreticandbreedingvalueandcouldbeusedinalloplas…  相似文献   

6.
Chromatinismadeupofregularlyspacedsubunits,nucleosomes.Ineukaryoticcells,chromatinisassembledimmediatedlyafterDNAreplication,butincellfreesystems,itcanbeassembledindependentofDNAreplicationwhenexogenousDNAwasaddedtoeggoroocyteextractsofXenopuslaevis.The…  相似文献   

7.
Identification of a novel DNA-binding protein to osmotin promoter   总被引:6,自引:0,他引:6  
Osmotinisa24kubasicproteinthatwasoriginallyidentifiedasthemostprominentpolypeptidepresentinsaltadaptedtobaccocells.Theexpressionofosmotinisinducedbymanystressesandenvironmentalfactorsincludingpathogeninfection,ethylene,ABA,Methyljasmonate,salicylicacid,w…  相似文献   

8.
Saccharomycescerevisiaeisanindustrialstrainwidelyusedintheproductionofethanol,breweryandsinglecellprotein(SCP).Butitisunabletofermentstarchduetothelackofamylolyticenzymes.Thestarchmustfirstbecooked,liquifiedandconvertedintoglucoseandthenutilizedincommer…  相似文献   

9.
Themicroenvironmentconstitutedbythymicstromalcellsisanimportantsiteforthedevelopmentofthymocytes.95%ofthymocytesdieinthethymuseveryday,inthewayofapoptosis[1].Thecelldeathismainlycausedbythedefaultofpositiveselectionandtheactionofnegativeselectionswhichar…  相似文献   

10.
Amolecularmarkercanbedesignatedascodominantordominanttypeaccordingtothegenotypicinformationprovided[1—4].Foracodominantmarker,threebandpatternscanbeobservedinelectrophoreticgels,whichcorrespondtotwocopiesoftheDNAsegmentsonthislocusbeinghomozygousP1type,h…  相似文献   

11.
1 IntroductionIntheearlyyearsofhumanhistory ,Paleolithicstoneartifactswerethemainculturalsymbols ,andtheyplayedtheleadingroleinearlyhominidactivitythroughouttheperiod .WithrespecttotheformingcausesofthePaleolithicindustrialfeaturesofasite ,manyscholarshaverecognizedtheimpor tanceofthenaturalenvironment[1] anddifferenthumaneconomicactivities[2 ] ,buttherelationshipbe tweenrawmaterialsandPaleolithicindustrialfeatureshasnotbeensufficientlyexplored[3] .Inalargenumberofresearchreports ,thestonematerialsareonlyid...  相似文献   

12.
Moststudiesonthereceptivefield(RF)organizationofvisualcortexneuronshavefocusedonitsspatialstructure.Stimuliinthenaturalvisualworld,however,includebothspatialandtemporalaspects.Foramorecompletefunctionaldescriptionofthevisualneurons,itisnecessarytoinvest…  相似文献   

13.
1 IntroductionAmongthefourMiocenehominoidsitesofKaiyuan ,Lufeng ,YuanmouandBaoshaninYunnanProvinceofChina ,LufengandYuanmouaretherichestfossilsites .Sinceitsfirstdiscoveryin 1 975,manycolleaguesaroundtheworldhavebeeninvolvedinthestudyofLufengpithecusfossils .However,noagreementhasbeenreachedontherelationshipofLufengpithecustootherMiocenehominoidsfoundaroundtheworldoronitsphylogeny .WuRukangbelievesthatthereareaseriesofmorphologicaldif ferencesbetweenLufengpithecusandtheSivapithecusspecimensfoundinTurkeyandP...  相似文献   

14.
生态位理论及其在森林生态学研究中的应用   总被引:47,自引:4,他引:43  
生态位理论及其在森林生态学研究中的应用朱春全(中国林业科学研究院林业研究所,北京100091)NichcTheoryanditsApplicationinForestEcology¥.ZhuChunquan(InslituteofForestry,ChineseAcademyofForestrySciences,Beijing100091),ChineseJournalofEcology,1993,12(4):41-46.Thedevelopmentofnichetheoryanditsapplicationinforestecologicalstudyarereviewedinthispaper.Itispointedoutthatthefunctionalactionofplantunitwasnotinvolvedinpreviousnicheconcepts,Theparticularitiesofnicheofplantunitarediscussedandanewmethodisdevelopedtodetermineitwithpho-tosyntheticproductionasafunct  相似文献   

15.
Scaffoldassociatedregion(SAR)andmatrixattachmentregion(MAR)areknownascisactingDNAelements,whichspecificallybindtonuclearscaffoldornuclearmatrix.SAR/MARareusually300—1000bplong,ATrich,andcontainingtopoisomeraseIIconsensussequenceandotherATrichsequencemotifs[1].…  相似文献   

16.
陆生脊椎动物生态学研究的过去、现在和将来(前苏联科学院动物进化形态学与生态学研究所,莫斯科)Past,PresentandFutureofEcologicalResearchonTerrcstrialVctebratcs¥.(InstituteofAnimalEvolutionaryMorphologyandEcology,theFormerAcademyofSclencesofSovietUnion).ChineseJournalofEcology,1993,12(4):66-71。Thispaperdescribesthemainstages,directionsanditemsofecologicalresearchintheformersovietU-nion.EcologicalresearchinthecountrywasrestrodedbymanysuUectiveandoUectivefactorsandstilllagsbehindtheworldlevelinmanyaspectssuchaspopulationdynamicstheory,communityresearch,eco-  相似文献   

17.
生态学的精神价值   总被引:1,自引:0,他引:1  
生态学的精神价值陈清硕(江苏农学院扬州225001)SpiritualValueofEcology¥.ChenQingshuo(JiangsuAgriculturalCollege,Yangzhou225001):ChineseJournalofEcology,1993,12(3):68-72.Thispaperdescribesthefunctionsofecologyintheprogressofsocialideologyandcivilization.Ecologyhelpsbringintobeingtheconstructionofascientificworldoutlookandincreasetheecologicalconscious-nessofmankind.Italsosuppliesatotaldevelopmentalpointofviewforthesocietyandprovidesagreataestheticvalue.Thespiritualvalueofecologyshouldneverbeneglected.Keywords:socialecology,ecol  相似文献   

18.
日本对虾野生种群和养殖群体的同功酶遗传变异   总被引:12,自引:0,他引:12  
PenaeidshrimpPenaeusjaponicus ,commonlynamedasFloweryShrimporBandedShrimp ,isoneofthemostcommer ciallyimportantspeciesofmarinecrustaceanfisheryinChina .Beingofthewarm waterspeciesconductingshortdistancemigra tion,theanimalismainlydistributedinthecoastalwa…  相似文献   

19.
Insectsarethemostsuccessfulanimalgroupintermsofnumbersofspecies.Althoughmanyfactorsmustcontributetotheprofusionofinsectspecies,onekeyelementisprobablyadevelopmentalplanthatincorporatesmetamorphosisanddiapause.Diapauseisacomplexadaptativeresponsewhichi…  相似文献   

20.
Electro-acupuncture-mediated gene transfer   总被引:2,自引:0,他引:2  
Somaticgenetherapyisbecomingincreasinglyimportantforpotentialtreatmentofgeneticandacquireddisorders,whichispromisinginclinicalapplication.GenetransferisoneofthekeytechniquesingenetherapythatallowsinstallationandexpressionofDNAdeliveredintotargetcells[1…  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