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排序方式: 共有316条查询结果,搜索用时 281 毫秒
91.
盛秀艳 《河北师范大学学报(自然科学版)》2003,27(5):438-440
图的顶点C-划分是指:G的顶点划分{V1,V2…,Vk},使得每个G[Vi]为多重完全图(1≤i≤k)。结合图的顶点C-划分的条件,确定了一类点的度在modulo4下值为0或3的上可嵌入图类,综合已有结果,较完整地刻画了这类图的上可嵌入情况。 相似文献
92.
93.
董占斌 《东华大学学报(自然科学版)》1999,(6)
消费需求是总需求的重要组成部分,是促进经济增长的重要动力.但是我国目前市场消费需求不足,已成为经济增长的主要制约因素.在分析影响消费需求的原因之后,提出了扩大消费需求的综合对策. 相似文献
94.
Malaguarnera L 《Cellular and molecular life sciences : CMLS》2006,63(24):3018-3029
The enzyme chitotriosidase (ChT), the human analogue of chitinases from non-vertebrate species, is one of the most abundant
and indicative proteins secreted by activated macrophages. Its enzymatic activity is elevated in serum of patients suffering
from Gaucher’s disease type 1 and in some other inherited lysosomal storage disorders, as well as in diseases in which macrophages
are activated. The last decade has witnessed the appearance of a substantial number of studies attempting to unravel its cellular
functions, which have yet not been fully defined. A great deal of progress has been made in the study of the physiological
roles of ChT. This review is looks at the key areas of investigations addressed to further illuminate whether ChT activation
might have different functional meanings in various diseases.
Received 7 June 2006; received after revision 24 July 2006; accepted 21 September 2006 相似文献
95.
Delhommeau F Pisani DF James C Casadevall N Constantinescu S Vainchenker W 《Cellular and molecular life sciences : CMLS》2006,63(24):2939-2953
Myeloproliferative disorders (MPDs) are clonal haematopoietic malignancies involving the abnormal proliferation of myeloid
lineages. The World Health Organisation (WHO) classification of haematopoietic malignancies distinguishes MPDs from myelodysplastic/
myeloproliferative disorders and systemic mastocytosis. These malignancies frequently involve constitutive tyrosine kinase
activity, resulting from either oncogenic fusion protein production or from point mutations. Chronic myelogenous leukaemia
is the model used for studies of the consequences of such molecular defects. However, the heterogeneity of the clinical course
of MPDs should be seen in a more rationale conceptual framework, including the many molecular events associated with these
diseases. This review focuses on the various tyrosine kinase-related molecular mechanisms underlying both MPDs and rare diseases
with myeloproliferative features. We pay particular attention to the newly identified JAK2 V617F mutation in polycythaemia
vera, essential thrombocythaemia and idiopathic myelofibrosis and deal with disease heterogeneity and putative additional
molecular mechanisms.
Received 9 June 2006; received after revision 28 July 2006; accepted 11 September 2006 相似文献
96.
Zisapel N 《Cellular and molecular life sciences : CMLS》2007,64(10):1174-1186
Sleep is a neurochemical process involving sleep promoting and arousal centers in the brain. Sleep performs an essential restorative
function and facilitates memory consolidation in humans. The remarkably standardized bouts of consolidated sleep at night
and daytime wakefulness reflect an interaction between the homeostatic sleep need that is manifested by increase in sleep
propensity after sleep deprivation and decrease during sleep and the circadian pacemaker. Melatonin, the hormone produced
nocturnally by the pineal gland, serves as a time cue and sleep-anticipating signal. A close interaction exists between the
sleep-wake, melatonin, core temperature, blood pressure, immune and hormonal rhythms leading to optimization of the internal
temporal order. With age the robustness of the circadian system decreases and the prevalence of sleep disorders, particularly
insomnia, increases. Deviant sleep patterns are associated with increased risks of morbidity, poor quality of life and mortality.
Current sleep pharmacotherapies treat insufficient sleep quantity, but fail to improve daytime functioning. New treatment
modalities for sleep disorders that will also improve daytime functioning remain a scientific and medical challenge. 相似文献
97.
From Creutzfeldt-Jakob disease (CJD) to variant CJD through Gerstmann-Str?ussler-Scheinker syndrome, kuru and fatal familial insomnia, the journey leading to current understanding of the basic aspects of human prion diseases has been full of unexpected, but often dramatic and always fascinating twists. Recent progress in modeling prion diseases and characterization of the various prion protein forms reveal that such a wide spectrum of the diseases is associated with the chameleon-like conformational features of prions. 相似文献
98.
文章将光滑粒子流体动力学(SPH)法应用于浅水方程,针对传统SPH法中存在的边界缺陷问题,引入了一种处理边界条件的方法,即虚粒子法,对一维溃坝问题进行模拟,并将所得结果与用有限差分法等数值方法得到的结果相比较,结果表明SPH法能够捕捉到水坝崩溃后的激波现象,并且所得图像较为平滑,在间断处也较为锐利。 相似文献
99.
Schwarz G 《Cellular and molecular life sciences : CMLS》2005,62(23):2792-2810
The molybdenum cofactor (Moco) forms the active site of all molybdenum (Mo) enzymes, except nitrogenase. Mo enzymes catalyze
important redox reactions in global metabolic cycles. Moco consists of Mo covalently bound to one or two dithiolates attached
to a unique tricyclic pterin moiety commonly referred to as molybdopterin (MPT). Moco is synthesized by an ancient and conserved
biosynthetic pathway that can be divided into four steps, according to the biosynthetic intermediates precursor Z (cyclic
pyranopterin monophosphate), MPT and adenylated MPT. In a fifth step modifications such as attachment of nucleotides, sulfuration
or bond formation between Mo and the protein result in different catalytic Mo centers. A defect in any of the steps of Moco
biosynthesis results in the pleiotropic loss of all Mo enzyme activities. Human Moco deficiency is a hereditary metabolic
disorder characterized by severe neurodegeneration resulting in early childhood death. Recently, a first substitution therapy
was established.
Received 17 June 2005; received after revision 18 August 2005; accepted 1 September 2005 相似文献
100.
结合边连通度,探讨了独立集中具有最小特定度和的点的上可嵌入图.得到了下列结果. (1)设G,是一个2-边连通简单图且满足条件:对任意一个G的3-独立集I, ∨xi ,xj ∈I (i,j = 1,2,3), d(xi ,xj)≧3 (1 ≦ i ≠ j ≦ 3) =>∑i = 13 d(xi) ≧ v + 1(v = | V(G)|}), 则G是上可嵌入的;(2)设G是一个3-边连通简单图且满足条件:对任意一个G的6-独立集I, ∨xi ,xj ∈I (1≦i,j≦6), d(xi,xj) ≧3(1 ≦ i ≠ j ≦ 6) => ∑i = 16 d(xi) ≧ v + 1(v = | V(G)|), 则G是上可嵌入的. 相似文献