全文获取类型
收费全文 | 713篇 |
免费 | 30篇 |
国内免费 | 447篇 |
出版年
2023年 | 3篇 |
2022年 | 20篇 |
2021年 | 6篇 |
2020年 | 11篇 |
2019年 | 61篇 |
2018年 | 29篇 |
2017年 | 82篇 |
2016年 | 72篇 |
2015年 | 52篇 |
2014年 | 27篇 |
2013年 | 7篇 |
2012年 | 51篇 |
2011年 | 45篇 |
2010年 | 35篇 |
2009年 | 35篇 |
2008年 | 35篇 |
2007年 | 49篇 |
2006年 | 45篇 |
2005年 | 32篇 |
2004年 | 26篇 |
2003年 | 18篇 |
2002年 | 19篇 |
2001年 | 35篇 |
2000年 | 39篇 |
1999年 | 49篇 |
1998年 | 20篇 |
1997年 | 28篇 |
1996年 | 26篇 |
1995年 | 31篇 |
1994年 | 35篇 |
1993年 | 10篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 54篇 |
1982年 | 5篇 |
1978年 | 4篇 |
1970年 | 2篇 |
1964年 | 2篇 |
1963年 | 2篇 |
1960年 | 2篇 |
1958年 | 2篇 |
1957年 | 11篇 |
1956年 | 2篇 |
排序方式: 共有1190条查询结果,搜索用时 15 毫秒
991.
Theskullisverybigandrobust,exceptionallyshortandwidthinproperty.Theroofascendslikeaflightofsteps.Occipitalistriangleinformandupperborderextendsposteriorly,projectedovertheoccipital.Theanteriorpartofupperpremolariswiderthanthatofposteriorone.TheprotoconeofP4isverysmall.LengthofM,islongerthanthatofP4.ItslimbswerediscoveredforfirsttimeinChina.Itisshownafterstudyingthatitsskullisexceptionallyrobustbutitslimbsdonotindicateanyrobust.ComparedwiththeHyaenasinensis,theskullofDinocrocutagiganteaisl.… 相似文献
992.
LATE JURASSIC PROTOSUCHIAN SICHUANOSUCHUS HUIDONGENSIS (ARCHOSAURIA: CROCODYLIFORMES) FROM ZIGONG, SICHUAN, CHINA 总被引:1,自引:1,他引:0
PENG Guanghao 《古脊椎动物学报》1996,(4)
AddihonaldiagnodsInternasialbarformedbypreInakilla;afaintmtCreSondorsalsurfaceoffrontalalongposterodorsalcomeroforbUpostorbitalcoInPleteyex-dudedfr0minfrateInporalfenestra;lengthofSymhysisbothanitSwidth;ventraledgeofangularexpandedtransverSeytoforml0ngitUdinalmwhalandlateralridges;denhckiinhpedgeofcheekteethlagrthanthoseinanteriorandposterioredges'RrmarksClosephylCgeneticrelahonshipsofShuhaandAstUngOSUchusfromtheInteJurassicandEariyCretaanusofthenorthernChinaareindicatalbythefollowing… 相似文献
993.
994.
INTRODUCTIONMa1n11la1iaIlskeletal1llusclefibresare(listiIlgl1ishedint()severaltypesacc()rdillgtodifferentclassificatiollscl1e111es.Eachtypeofmusc1efibresl1asasetofspecificcharacteristics.Ollewell-kllowl1waytoclassifymusclefibresistodividethemintotwobroadtypestslow-twitcI1ortypeIfibres,andfast-twitchortypelIfibres.ThefOrmerllormallyappearsreda11dthelaterappearswhite.Theypossesswidedifferellceswithrespectt()physiol()gical,biochemical,andmorpho1ogica1pl1ellotypiccharacteristics,suchasisom… 相似文献
995.
ZHANG WANHUI YUNLONG ZHU FUZHOU WANG YUZHEN HU QI MEI CHAO ZHAO JIANGKANG CHEN 《Cell research》1995,5(2):197-207
The undecapeptide substanceP(SP) was shown to be intimately involved in both the structural and functional aspects of the anterior pituitary.Yet,in addition to its influences on hormonal secretion,SP may well possess more actions in this master gland.The present study was ftherefore aimed to investigate the effect of SP on the proliferation of rat anterior pituitary cells in primary culture,It was found that SP could dose-dependently increase the incorporation of tritiated thymidine(3H-TdR) into cultured anterior pituitary cells.Other mammalian tachykinins such as neurokinin A and neurokinin B had similar effect but to varying degrees.The equipotent analogue of SP,Norleucine^11-SP(Nle^11-SP),also acted likewise.with its action antagonizable by spantide,a SP receptor blocker.To further characterize the nature of cells responsive to the challenge of SP,immunocytochemical staining against S-100 protein and some adenohypophyseal hormones was performed alone or plus autoradiography.The results showed that the percentage of S-100 proteinimmunorective cells was apparently elevated by the addtion of Nle^11-Sp for 48h,which indicates a preferential proliferation of folliculo-stellate cells under the regime .This was confirmed by increases in immunocytochemical or autoradiographical labelling indices of anterior pituitary Substance P and anterior pituitary cell proliferation.Cells treated similarly.Taken together,These results reveal that the trophic action of SP observed previously in other tissues is also present at least in cultured rat anterior pituitary cells.with responding cells being predominantly folliculo-stellate cells as typified by S-100 proteinimmunoreactivity.Therefore,an intra-pituitary trophicaction of SP in vivo could be anticipated. 相似文献
996.
l!ntroductionAutonomousLotka-VolterramutuallstlcsystemhasbeenstudiedInmanypaperE3】,E4].[5】,ourpurposehereIstoconsiderthenonautonomouStwo-SPPCllsLOtkt-Volterramutuallstlcsystem.WeareconcernedwiththedifferentialequationsbelongtoC‘andC‘isthesetOfsllCOlltlnuouSfunCtionSg:[0,+。)、RbOUnded。hove。ndbelOWbyCOnst。ms,moreover,notallofa:。(t)(l<l,j<n,。/j)arezero.Theper。odlccasehasbeenconsideredIn[1】.Insection3ofthlspaper,westudiedthegeneralcaseoftlmede… 相似文献
997.
INTRODUCTIONTherearesomekindsofcorrelatedrelationshiPsbetweenagronomytraitsIntndtcarice.Geneticandenvlronmentatcorrelat[onshavebeenanalyzedforsometraitsInrice[‘·’J.LiandYangfoundadditivecorrelationcoefficientswerefrom一0.773to0·993forsomeflowertraitsInrice[’].Yuhavefoundthataddltlvecorrelationwasslgnlflcantforsometraitsinbarley[13].Uptonow,partitioningthegenotyplccovarlanceoftraitsInricehasnomorethanaddltlveanddominancecovarlancecomponents.kcausethenutrl-**t吕Of凡8… 相似文献
998.
A NEW HYOPSODUS FROM THE EARLY EOCENE OF FANGXIAN, HUBEI 总被引:1,自引:0,他引:1
Huang Xueshi 《古脊椎动物学报》1995,(1)
CondylarthraCoPe,l88lHyopsodontidaeTrouessart,l879HyopsodusLeidy,l87oHyopsodusfangxianensissp.nov.TypeArightmendibularfragmelltpreservingml-ln3(IVPPVl2oo5).LocalityandhorizonLuojiagou,Fangx1anCou11ty,HubeiProvince;EarlyEoceneYoupingFormation.Diagnosism24.5mmlong.Thelel1gthofm1a11dm2ncar1yequal.m1andm2re1ativelywideafldIObustwhilem3narrowands1cn(ler.Noparaconidandme-tasty1idonthemo1ars.Hypoconu11dmoredevelopedandsituatednearthemiddleofthetoothonthefirsttwolowermolars-EtymologyTrivia… 相似文献
999.
THE GEOLOGICAL SIGNIFICANCE OF SINACANTHUS FROM TARIM, CHINA 总被引:1,自引:0,他引:1
Liu Shifan 《古脊椎动物学报》1995,(2)
TheSinacanthusfossiIlocalitieswererestrictedtotheYangtzeregionbeforethediscoveryoftheTarimfossils.TheyusedtobereferredtoasDevonianorEarlyDevonianinage,butlaterdiscoverieshavedemostratedthattheageofSinacanthus-bearingbedsshou1dbeSilurian(Li,198O).In1988,fiveSinacanthusfossill,edswerefoundintheTataertagPormationofKalping,NWTarimandtheageoftheTataertagFormationwasconsideredMiddle-LateSilurian(Table2).Inthesummerofl992,WangJunqing,ZhuMinandtheauthorofthispaperfoundalotoffossilfinspinesi… 相似文献
1000.
近年来我们结合有关疾病的防治工作,先后在云南省采到葛李恙螨亚属(SubgenusGahrliepia Oudemans,1912)二新种,记述如下。 宽痕葛李恙螨Gahrliepia(Gahrliepia)eurypunctata新种(图1—5) 鉴别特征 本新种与重庆葛李恙螨G.(G.)chungkingensis Jeu et al.,1963较近似,主要区别是:(1)本种须毛式为B-B-NNB,而非B-B-NNN。(2)盾板上的大形痘痕分布广,在感器前后方均有,而并非仅见于感器的后方。(3)背毛33—34根,而非48—49根。 相似文献