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91.
为探索富勒烯及其水溶性衍生物对哺乳动物卵母细胞减数分裂的作用,使用富勒烯膦酸衍生物(2P)、富勒烯-PVP和富勒醇作用于体外培养的小鼠GV期卵母细胞和超排卵母细胞,通过观察第一极体排出率和原核形成率以判断卵母细胞的成熟和激活,并探讨光照对这一作用的影响.结果表明,在光照和非光照下,富勒烯的PVP水溶液、富勒醇对卵母细胞的成熟没有明显影响,而2P在光照下对卵母细胞的成熟和孤雌激活具有明显抑制作用,其作用有浓度依赖性. 相似文献
92.
根据不同的岩浆侵入地层方式以及围岩内孔隙水是否发生气化建立了四种热传导模型,以苏格兰西北部Skye岛的辉绿岩岩墙为实例分别采用这四种热传导模型数值模拟了侵入体相邻泥质烃源岩有机质的成熟度。模拟结果显示:(1)岩浆的侵入方式能显著地影响热传导模型对侵入体围岩成熟度的预测,岩浆有限时间侵入方式的假设下热传导模型所预测的镜质体反射率(Ro)与假设岩浆瞬间侵入方式的模型相比,最大偏差处低2.13%~2.59%;(2)当岩浆侵入方式相同时,考虑孔隙水气化的模型预测的Ro普遍低于不考虑孔隙水气化的模型。孔隙水气化引起Ro的最大偏差达0.71%~0.91%,明显低于岩浆的侵入方式对围岩成熟度预测结果的影响;(3)不考虑围岩内孔隙水的气化且假设岩浆有限时间侵入地层的热传导模型所预测的Ro与实测值十分吻合,说明岩浆侵入方式应为有限时间侵入且围岩孔隙水的气化作用不显著,该模型是否适用于其他地区,还有待于进一步研究。 相似文献
93.
94.
BU Shumin XIA Guoliang XIE Huirong & GUO Yong College of Biological Science China Agricultural University Beijing China Correspondence should be addressed to Xia Guoliang 《科学通报(英文版)》2003,48(1)
In recent years, embryo engineering concerning animal cloning, animal transgene and bioreactor technique has been developed rapidly. Since the operation of each of these techniques needs matured mammalian oocytes, the demand for highly qualified oocytes is expanding. On the other hand, various factors existing in follicle might be involved in oocyte meiotic maturation, and the process involved is extremely complex and inadequately defined. As a result, the mechanism of oocyte maturation regula… 相似文献
95.
A. Hasilik 《Cellular and molecular life sciences : CMLS》1992,48(2):130-151
Lysosomal enzymes are subjected to a number of modifications including carbohydrate restructuring and proteolytic maturation. Some of these reactions support lysosomal targeting, others are necessary for activation or keeping the enzyme inactive before being segregated, while still others may be adventitious. The non-segregated fraction of the enzyme is secreted and can be isolated from the medium. It is considered that the secreted lysosomal enzymes fulfill certain physiological and pathophysiological roles. By comparing the secreted and the intracellular enzymes it is possible to distinguish between the reactions that occur before and after the segregation. In this review the reactions that may influence the segregation are referred to as the early processing and those characteristic for the enzymes isolated from lysosomal compartments as the late processing. The early processing is characterized mainly by modifications of carbohydrate side chains. In the late processing, proteolytic fragmentation represents the most conspicuous changes. The review focuses on the compartmentation of the reactions and the proteolytic fragmentation of lysosomal enzyme precursors. While a plethora of proteolytic reactions are involved, our knowledge of the proteinases responsible for the particular maturation reactions remains very limited. The review points also to work with cells from patients affected with lysosomal storage disorders, which contributed to our understanding of the lysosomal apparatus. 相似文献
96.
Mari SA Soragna A Castagna M Santacroce M Perego C Bossi E Peres A Sacchi VF 《Cellular and molecular life sciences : CMLS》2006,63(1):100-111
We investigated the role of the Q291 glutamine residue in the functioning of the rat γ-aminobutyric acid (GABA) transporter
GAT-1. Q291 mutants cannot transport GABA or give rise to transient, leak and transport-coupled currents even though they
are targeted to the plasma membrane. Coexpression experiments of wild-type and Q291 mutants suggest that GAT-1 is a functional
monomer though it requires oligomeric assembly for membrane insertion. We determined the accessibility of Q291 by investigating
the impact of impermeant sulfhydryl reagents on cysteine residues engineered in close proximity to Q291. The effect of these
reagents indicates that Q291 faces the external aqueous milieu. The introduction of a steric hindrance close to Q291 by means
of [2-(trimethylammonium)ethyl] methanethiosulfonate bromide modification of C74A/T290C altered the affinity of the mutant
for cations. Taken together, these results suggest that this irreplaceable residue is involved in the interaction with sodium
or in maintaining the cation accessibility to the transporter.
Received 24 October 2005; accepted 11 November 2005 相似文献
97.
98.
《科学通报(英文版)》1999,44(17):1600-1600
The low-temperature and low-pressure artificial hydropyrolysis experiment proves that at the immature-low mature thermal evolution stage of source rock, the condensation reaction and the thermal degradation reaction occur continuously and simultaneously in both soluble organic matter and insoluble organic matter. This process was called \"antipole evolution\", which means transformation into two opposing extremes. The soluble organic matter and insoluble organic matter constitute an organic related integrity, transforming mutually in a dynamic equilibrium. Non-hydrocarbon and asphaltene are key intermediates between kerogen and hydrocarbon . Asphaltene is one of the major sources of immature hydrocarbons. 相似文献
99.
100.
赵世玉;赵刚 《中国科学技术大学学报》2023,53(9):0902-1-0902-16
There have been increasing requirements for women’s fertility preservation due to oncological and nononcological reasons in recent years, and meeting these demands will be a hot topic in the coming years. Oocyte cryopreservation is a workable option for preserving women’s fertility, and great advances have already been made and much progress has been made in mammalian gene banking and human oocyte banks. In this paper, we systematically introduce the history of oocyte cryopreservation and vitrification technology and highlight the vitrification carrier. Furthermore, we summarize the fundamentals of oocyte vitrification and discuss the effects of vitrification on oocyte quality. Strategies to improve the effect of oocyte cryopreservation are also proposed. At the end of this review, we conclude oocyte cryopreservation and outline future perspectives. 相似文献