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41.
通过制备Plcd1转基因小鼠研究Plcd1基因功能.首先逆转录PCR获得约2.2kb的Plcd1基因全长,T载体克隆后测序验证;以pMD19-T-Plcd1为模板,通过设计引物及PCR扩增引入酶切位点,与pEF6/V5-His同时进行酶切、连接,构建pEF6/V5-His-Plcd1表达载体;经真核表达验证后,酶切获得目标片段,显微注射681枚受精卵,在82只仔鼠中获得转基因阳性首建鼠15只,其中13只稳定遗传并建系.PLCD1-HIS融合蛋白在睾丸组织中表达,在皮肤组织中无表达.Plcd1转基因小鼠为Plcd1功能研究奠定了基础. 相似文献
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Summary To produce antisera of high antibody concentration animals after sensitization with protein have been reinjected with lethal doses of the antigen, protected against the shock-effect by substances with antihistamin properties (as example Antistin). The antibody concentration was considerably higher in these animals as in the other non-protected group reinjected with the highest tolerated antigen dosage. 相似文献
44.
White TD WoldeGabriel G Asfaw B Ambrose S Beyene Y Bernor RL Boisserie JR Currie B Gilbert H Haile-Selassie Y Hart WK Hlusko LJ Howell FC Kono RT Lehmann T Louchart A Lovejoy CO Renne PR Saegusa H Vrba ES Wesselman H Suwa G 《Nature》2006,440(7086):883-889
The origin of Australopithecus, the genus widely interpreted as ancestral to Homo, is a central problem in human evolutionary studies. Australopithecus species differ markedly from extant African apes and candidate ancestral hominids such as Ardipithecus, Orrorin and Sahelanthropus. The earliest described Australopithecus species is Au. anamensis, the probable chronospecies ancestor of Au. afarensis. Here we describe newly discovered fossils from the Middle Awash study area that extend the known Au. anamensis range into northeastern Ethiopia. The new fossils are from chronometrically controlled stratigraphic sequences and date to about 4.1-4.2 million years ago. They include diagnostic craniodental remains, the largest hominid canine yet recovered, and the earliest Australopithecus femur. These new fossils are sampled from a woodland context. Temporal and anatomical intermediacy between Ar. ramidus and Au. afarensis suggest a relatively rapid shift from Ardipithecus to Australopithecus in this region of Africa, involving either replacement or accelerated phyletic evolution. 相似文献
45.
复杂设备运行的协同服务支持 总被引:5,自引:0,他引:5
针对现有的设备服务模式存在的问题,提出支持复杂设备优化运行的协同服务模式.为了使复杂设备能充分发挥其潜在价值,指出复杂设备的运行应该与必需的技术服务关联起来,形成“产品服务捆绑体”.解释了支持复杂设备运行的协同服务内涵,并对组织结构形式、协同服务业务模式识别和过程建模关键技术进行系统论述,提出了建立嵌入式在线服务标准(embeddedo nline service,EOS)作为支持协同服务运行的设备接入技术. 相似文献
46.
The hierarchical organization (HO) that has provided the prevailing model for business management for most of this century has been challenged repeatedly during the last 20 to 30 years. Matrix Management (MM), Total Quality Management (TQM), and Business Process Reengineering (BPR) are just three in the long line of approaches that have been suggested to remedy some of the problems with HO. Although these approaches have showed great promise, they either have been abandoned (MM), are on their way out (TQM), or are experiencing serious problems (BPR) in a large number of organizations that have tried to implement them. Yet many of these organizations have managed to make these approaches work. It is suggested in this paper that the main reasons for the failures do not lie in the models themselves, each of which have considerable merits, but in the absence of an overall theoretical framework, within which the various models could be validated and amalgamated. The authors are of the opinion that teleonics (proposed by Járos and Cloete, 1987) could serve as the basis for such a framework, which could thus be called the Teleonic Management Framework (TMF). 相似文献
47.
刘健 《华东理工大学学报(自然科学版)》1996,(4)
考察了文题材料的蠕变行为,发现其以取决于所施加的应力与温度而出现的蠕变第一、第二、第三阶段为特征。蠕变过程中出现的主要结构变化为纤维重排、富碳界面层的氧化以及基质中晶体的生长。虽然复合材料的受力极限取决于残余玻璃相,但纤维的引入使得材料的热机械性能得以大幅度地提高。 相似文献
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Cytosolic pH regulates root water transport during anoxic stress through gating of aquaporins 总被引:2,自引:0,他引:2
Tournaire-Roux C Sutka M Javot H Gout E Gerbeau P Luu DT Bligny R Maurel C 《Nature》2003,425(6956):393-397
Flooding of soils results in acute oxygen deprivation (anoxia) of plant roots during winter in temperate latitudes, or after irrigation, and is a major problem for agriculture. One early response of plants to anoxia and other environmental stresses is downregulation of water uptake due to inhibition of the water permeability (hydraulic conductivity) of roots (Lp(r)). Root water uptake is mediated largely by water channel proteins (aquaporins) of the plasma membrane intrinsic protein (PIP) subgroup. These aquaporins may mediate stress-induced inhibition of Lp(r) but the mechanisms involved are unknown. Here we delineate the whole-root and cell bases for inhibition of water uptake by anoxia and link them to cytosol acidosis. We also uncover a molecular mechanism for aquaporin gating by cytosolic pH. Because it is conserved in all PIPs, this mechanism provides a basis for explaining the inhibition of Lp(r) by anoxia and possibly other stresses. More generally, our work opens new routes to explore pH-dependent cell signalling processes leading to regulation of water transport in plant tissues or in animal epithelia. 相似文献
50.
Tafti M Petit B Chollet D Neidhart E de Bilbao F Kiss JZ Wood PA Franken P 《Nature genetics》2003,34(3):320-325
In rodents, the electroencephalogram (EEG) during paradoxical sleep and exploratory behavior is characterized by theta oscillations. Here we show that a deficiency in short-chain acyl-coenzyme A dehydrogenase (encoded by Acads) in mice causes a marked slowing in theta frequency during paradoxical sleep only. We found Acads expression in brain regions involved in theta generation, notably the hippocampus. Microarray analysis of gene expression in mice with mutations in Acads indicates overexpression of Glo1 (encoding glyoxylase 1), a gene involved in the detoxification of metabolic by-products. Administration of acetyl-L-carnitine (ALCAR) to mutant mice significantly recovers slow theta and Glo1 overexpression. Thus, an underappreciated metabolic pathway involving fatty acid beta-oxidation also regulates theta oscillations during sleep. 相似文献