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71.
Myosin was purified from wheat mitochondria using DE-52 anion exchange chromatography and Sephacryl S-300 gel filtration. The molecular weight of its heavy chain is about 210 ku, similar to that of muscle myosin Ⅱ(205 ku), and it could be recognized by the polyclonal antibodies against human skeletal muscle myosin Ⅱ. The ATPase activity of the mitochondrial myosin stimulated by F-actin from chicken muscle is 202.5 nmoles Pi/min·mg. The mitochondrial myosin could be activated by Ca2+ and was not inhibited by Ca2+ at high concentration. The results demonstrate that the myosin of wheat mitochondria shares some similarities with the skeletal muscle myosin Ⅱ. 相似文献
72.
本文应用模态参数识别与试验模态分析技术.对专用起重机塔架系统的自振特性进行了试验研究.同时对其振动横态参数做了理论计算,取得了较为一致的成果. 相似文献
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74.
含硫、氮席夫碱-3d-金属配合物的研究(Ⅰ)——2,4-二羟基苯甲醛缩氨基硫脲及其铜(Ⅱ)配合物的合成、表征和抗菌活性~* 总被引:1,自引:0,他引:1
本文报导了2,4-二羟基苯甲醛缩氨基硫脲与铜(Ⅱ)的配合物的合成方法、红外光谱、紫外光谱、元素分析等特征及抗菌活性。它们都是未见文献报导的新的化合物。 相似文献
75.
报道了偶氮氯膦-pA用于痕量贵金属元素钌、铑、钯、饿、铱、铂的测定研究及应用.偶氮氯膦-pA与贵金属钯在硝酸介质中表现为显色反应,建立了光度法测定痕量钯的新方法;而偶氮氯膦-pA在微量贵金属离子钌、铑、铂、饿、铱存在下与氧化剂(高碘酸钾、溴酸钾)的催化褪色反应,则建立了测定这些金属元素的催化分光光度新方法.动力学分析建立了相关的线性方程.本文考察了该系列反应的最佳条件、如反应时间、吸收曲线、检出限及线性范围等.此类方法可直接在水溶液中进行,简便快速,灵敏度高,用于贵金属精矿、催化剂等样品中微量铂系元素的测定,结果满意. 相似文献
76.
Vennerstrom JL Arbe-Barnes S Brun R Charman SA Chiu FC Chollet J Dong Y Dorn A Hunziker D Matile H McIntosh K Padmanilayam M Santo Tomas J Scheurer C Scorneaux B Tang Y Urwyler H Wittlin S Charman WN 《Nature》2004,430(7002):900-904
The discovery of artemisinin more than 30 years ago provided a completely new antimalarial structural prototype; that is, a molecule with a pharmacophoric peroxide bond in a unique 1,2,4-trioxane heterocycle. Available evidence suggests that artemisinin and related peroxidic antimalarial drugs exert their parasiticidal activity subsequent to reductive activation by haem, released as a result of haemoglobin digestion by the malaria-causing parasite. This irreversible redox reaction produces carbon-centred free radicals, leading to alkylation of haem and proteins (enzymes), one of which--the sarcoplasmic-endoplasmic reticulum ATPase PfATP6 (ref. 7)--may be critical to parasite survival. Notably, there is no evidence of drug resistance to any member of the artemisinin family of drugs. The chemotherapy of malaria has benefited greatly from the semi-synthetic artemisinins artemether and artesunate as they rapidly reduce parasite burden, have good therapeutic indices and provide for successful treatment outcomes. However, as a drug class, the artemisinins suffer from chemical (semi-synthetic availability, purity and cost), biopharmaceutical (poor bioavailability and limiting pharmacokinetics) and treatment (non-compliance with long treatment regimens and recrudescence) issues that limit their therapeutic potential. Here we describe how a synthetic peroxide antimalarial drug development candidate was identified in a collaborative drug discovery project. 相似文献
77.
Neurofibrillary tangles, amyotrophy and progressive motor disturbance in mice expressing mutant (P301L) tau protein 总被引:29,自引:0,他引:29
Lewis J McGowan E Rockwood J Melrose H Nacharaju P Van Slegtenhorst M Gwinn-Hardy K Paul Murphy M Baker M Yu X Duff K Hardy J Corral A Lin WL Yen SH Dickson DW Davies P Hutton M 《Nature genetics》2000,25(4):402-405
Neurofibrillary tangles (NFT) composed of the microtubule-associated protein tau are prominent in Alzheimer disease (AD), Pick disease, progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Mutations in the gene (Mtapt) encoding tau protein cause frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), thereby proving that tau dysfunction can directly result in neurodegeneration. Expression of human tau containing the most common FTDP-17 mutation (P301L) results in motor and behavioural deficits in transgenic mice, with age- and gene-dose-dependent development of NFT. This phenotype occurred as early as 6.5 months in hemizygous and 4.5 months in homozygous animals. NFT and Pick-body-like neuronal lesions occurred in the amygdala, septal nuclei, pre-optic nuclei, hypothalamus, midbrain, pons, medulla, deep cerebellar nuclei and spinal cord, with tau-immunoreactive pre-tangles in the cortex, hippocampus and basal ganglia. Areas with the most NFT had reactive gliosis. Spinal cord had axonal spheroids, anterior horn cell loss and axonal degeneration in anterior spinal roots. We also saw peripheral neuropathy and skeletal muscle with neurogenic atrophy. Brain and spinal cord contained insoluble tau that co-migrated with insoluble tau from AD and FTDP-17 brains. The phenotype of mice expressing P301L mutant tau mimics features of human tauopathies and provides a model for investigating the pathogenesis of diseases with NFT. 相似文献
78.
79.
Four deletion mutantDictyostelium myosin II heavy chain genes, MyΔ824-941 (Δ1/ 3S2), MyΔ934-1454 (ΔS2), MyΔ934-1194 (ΔS2-1) and MyΔ1 157–1454 (ΔS2-2), were
transformed by standard electfoporation into mhcA-cells (T-null), a mutantDictyostelium cell devoid of endogenous myosin II heavy chain gene. The growth, development and formation of fruiting bodies of cells expressing
those mutant myosin II s under suspension culture were investigated by comparison with the wild type cell. The results indicate
that internal deletion of myosin II affeds the growth and development ofDictyastelium. Furthermore, the longer the length of deletion, the more serious the defect in phenotype. 相似文献
80.