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891.
目的:观察Bcl-2 和COX-2 在正常宫颈和宫颈鳞癌中的表达情况,并探讨其与宫颈鳞癌发生发展的关系。方法:应用免疫组 织化学S-P法检测40 例宫颈鳞癌组织、10 例正常宫颈组织中Bcl-2 和COX-2 的表达情况。结果:(1)Bcl-2 在正常宫颈组织和宫颈 鳞癌组织中的阳性表达率分别为30.0%、72.5 %(P<0.05),而COX-2在正常宫颈组织和宫颈鳞癌组织中的阳性表达率分别为0.0 %、 60.0 %(P<0.05)。(2)在宫颈鳞癌中,Bcl-2 的表达与宫颈鳞癌的病理分级、临床分期以及淋巴结转移无关(P>0.05),而COX-2 的表达 与宫颈鳞癌的病理分级及淋巴转移有关(P<0.05),与临床分期无关(P>0.05)。(3)Spearman 等级相关性分析显示宫颈鳞癌组织中 Bcl-2 和COX-2的表达呈正相关(r=0.517,P<0.01)。结论:Bcl-2 和COX-2 在宫颈鳞癌中的表达升高并呈显著正相关,且COX-2的 表达与宫颈鳞癌的淋巴转移有关,二者在宫颈癌的发生发展中可能起重要作用,有可能作为评估宫颈鳞癌淋巴结转移的参考指 标。  相似文献   
892.
目的:研究livin 蛋白在非小细胞肺癌中的表达及其与非小细胞肺癌的生物学特性及临床预后的关系。方法:通过免疫组化 的方法检测和比较88 例非小细胞肺癌组织和20例癌旁正常肺组织中livin 蛋白的表达,并分析其与非小细胞肺癌的临床病理特 征和预后的相关性。结果:非小细胞肺癌组织及癌旁正常肺组织中livin 蛋白的阳性表达率分别为54.55%和5%,差异有显著统计 学差异(P<0.05)。非小细胞肺癌组织中livin 蛋白的表达水平与淋巴结转移、TNM分期显著相关(P<0.05),但与患者的性别、年龄、 分化程度及病理学类型无关(P>0.05)。Livin 高表达的非小细胞肺癌患者生存时间显著短于livin 低表达的患者(P<0.05)。结论: Livin 蛋白在非小细胞肺癌的发生及发展中起重要作用并与患者的预后相关,可能作为非小细胞肺癌新的防治靶点。  相似文献   
893.
Amphioxus, also called lancelet or cephalochordate, is a promising model organism owning to its particularly evolu- tionary position, simple genome content and comparable body plan to that of vertebrates (Holland et aL, 2004; Bertrand and Escriva, 2011). However, use of amphioxus as a model or- ganism has been limited for many years because of lack of an efficient genomic modification method. Recently, several revolutionary gene targeting methods that could induce directed mutations, insertions and deletions at intended target sites, have been developed (Gaj et al., 2013).  相似文献   
894.
佟丹  朱莉  刘磊  林楠  肖巍 《生物磁学》2014,(3):486-489
目的:观察Bcl-2和COX-2在正常宫颈和宫颈鳞癌中的表达情况,并探讨其与宫颈鳞癌发生发展的关系。方法:应用免疫组织化学s-P法检测40例宫颈鳞癌组织、10例正常宫颈组织中Bcl-2和COX-2的表达情况。结果:(1)Bcl-2在正常宫颈组织和宫颈鳞癌组织中的阳性表达率分别为30.0%、72.5%(P〈0.05),而COX-2在正常宫颈组织和宫颈鳞癌组织中的阳性表达率分别为0.0%、60.0%(P〈0.05)。(2)在宫颈鳞癌中,Bcl-2的表达与宫颈鳞癌的病理分级、临床分期以及淋巴结转移无关(P〉0.05),而COX-2的表达与宫颈鳞癌的病理分级及淋巴转移有关(P〈0.05),与临床分期无关(P〉0.05)。(3)Spearman等级相关性分析显示宫颈鳞癌组织中Bcl-2和COX-2的表达呈正相关(r=0.517,P〈0.01)。结论:Bcl-2和COX-2在宫颈鳞癌中的表达升高并呈显著正相关,且COX-2的表达与宫颈鳞癌的淋巴转移有关,二者在宫颈癌的发生发展中可能起重要作用,有可能作为评估宫颈鳞癌淋巴结转移的参考指标。  相似文献   
895.
《Epigenetics》2013,8(11):1308-1318
DNA methylation is essential in brain function and behavior; therefore, understanding the role of DNA methylation in brain-based disorders begins with the study of DNA methylation profiles in normal brain. Determining the patterns and scale of methylation conservation and alteration in an evolutionary context enables the design of focused but effective methylation studies of disease states. We applied an enzymatic-based approach, Methylation Mapping Analysis by Paired-end Sequencing (Methyl-MAPS), which utilizes second-generation sequencing technology to provide an unbiased representation of genome-wide DNA methylation profiles of human and mouse brains. In this large-scale study, we assayed CpG methylation in cerebral cortex of neurologically and psychiatrically normal human postmortem specimens, as well as mouse forebrain specimens. Cross-species human-mouse DNA methylation conservation analysis shows that DNA methylation is not correlated with sequence conservation. Instead, greater DNA methylation conservation is correlated with increasing CpG density. In addition to CpG density, these data show that genomic context is a critical factor in DNA methylation conservation and alteration signatures throughout mammalian brain evolution. We identify key genomic features that can be targeted for identification of epigenetic loci that may be developmentally and evolutionarily conserved and wherein aberrations in DNA methylation patterns can confer risk for disease.  相似文献   
896.
897.
Melanism is an important component of insect cuticle and serves numerous functions that enhance fitness. Despite its importance, there is little information on its genetic basis or its phenotypic and genetic correlation with fitness‐related traits. Here, we examine the heritability of melanism in the wing dimorphic sand cricket and determine its phenotypic and genetic correlation with wing morphology, gonad mass and size of the dorso‐longitudinal muscles (the principle flight muscles). Previously demonstrated trade‐offs among these traits are significant factors in the evolution of life history variation. Using path analysis, we show that melanization is causally related to gonad mass, but not flight muscle mass. Averaged over the sexes, the heritability of melanism was 0.61, the genetic correlation with gonad mass was ?0.36 and with wing morph was 0.51. The path model correctly predicted the ranking of melanization score in lines selected for increased ovary mass, increased flight muscle mass, an index that increased both traits and an unselected control. Our results support the general hypothesis that melanization is costly for insects and negatively impacts investment in early reproduction.  相似文献   
898.
Growth trajectories often impact individual fitness. They are continuous by nature and so are amenable to analysis using a function‐valued (FV) trait framework to reveal their underlying genetic architecture. Previous studies have found high levels of standing additive genetic (co)variance for growth trajectories despite the expectation that growth should be responding to frequent strong directional selection. In this study, the FV framework is used to estimate the additive genetic covariance function for growth trajectories in larval Tribolium castaneum to address questions about standing additive genetic (co)variance and possible evolutionary constraints on growth and to predict responses to four plausible selection regimes. Results show that additive genetic (co)variance is high at the early ages, but decreases towards later ages in the larval period. A selection gradient function of the same size and in the same direction of the first eigenfunction of the G‐function should give the maximal response. However, evolutionary constraints may be acting to keep this maximal response from being realized, through either conflicting effects on survivability and fecundity of larger body size, few evolutionary directions having sufficient additive variance for a response, genetic trade‐offs with other traits or physiological regulatory mechanisms. More light may be shed on these constraints through the development of more sophisticated statistical approaches and implementation of additional empirical studies to explicitly test for specific types of constraints.  相似文献   
899.
Biotic invasions provide a natural experiment in evolution: when invasive species colonize new ranges, they may evolve new clines in traits in response to environmental gradients. Yet it is not clear how rapidly such patterns can evolve and whether they are consistent between regions. We compare four populations of the invasive cabbage white butterfly (Pieris rapae) from North America and Japan, independently colonized by P. rapae 150 years ago and 300 years ago, respectively. On each continent, we employed a northern and southern population to compare the effects of latitude on body mass, development rate and immune function. For each population, we used a split‐sibling family design in which siblings were reared at either warm (26.7 °C) or cool (20 °C) temperatures to determine reaction norms for each trait. Latitudinal patterns in development time were similar between the two continents. In contrast, there were strong geographical differences in reaction norms for body size, but no consistent effects of latitude; there were no detectable effects of latitude or continent on immune function. These results imply that some life history traits respond consistently to selection along climatic gradients, whereas other traits may respond to local environmental factors, or not at all.  相似文献   
900.
The evolutionary history of vascular plants is reviewed by extrapolation back through time from a wide range of data recently derived from the present flora, using as the central theme evolutionary inferences gained from phylogenies reconstructed as cladograms. Any region of the genome can be used to infer relationships, but only a combination of knowledge of morphology and the developmental genes that underpin morphology can allow evolutionary interpretation of macroevolutionary transitions; this in turn is necessary to identify bona fide evolutionary radiations and any putative causal key innovations. Such studies require clades to be delimited not by the inclusion of particular extant ‘crown’ species but rather by specific apo‐morphies, thereby giving important phylogenetic roles to extinct as well as extant species. Dating phylogenetic divergences via molecular clocks remains seriously inaccurate, and ultimately relies primarily on fossil benchmarks. First principles suggest that evolution of most regions of the genome is fundamentally gradual, whereas evolution of regions especially prone to strong selection pressure, and of the many facets of the phenotype, is punctuational, being characterized through time dominantly by stasis. Sequence data have proved valuable for inferring monophyletic groups, but within the now widely accepted context of monophyly the taxonomic hierarchy should primarily reflect degrees of morphological rather than molecular divergence. Incongruence among contrasting data sets is best explained by understanding the biological constraints operating on each type of phylogenetic information. The conventional ‘uniformitarian’ view of evolution has only limited applicability as one traces the history of land plants through time. Diversity increased in stepwise fashion, reflecting either attainments of complexity and/or fitness thresholds by the lineage (intrinsic) or the availability of unusually permissive environments, often following major perturbations (extrinsic). The Quaternary period demonstrates especially well the resilience, and ease of migration, of the Earth's vegetation. A higher frequency of generation of novel phenotypes in the deep past is possible, but a far higher frequency of their establishment is certain; together, these factors generate an evolutionary pattern of nested radiations that is fractal, as saturation of the resource space rendered the environment decreasingly permissive through time. In the immediate future, evolutionary‐developmental genetics will have increasing value for testing homology, interpreting homoplasy and elucidating evolutionary constraints, and will become easier to pursue as whole‐genome sequences of additional ‘model’ species further invigorate comparative genomics. Complexity of gene regulation, both by other genes and by the cellular and extra‐cellular environment, appears a particularly fruitful area for further research. Nonetheless, environmental filtering of evolutionary novelties (whether instantaneously isolated mutant ‘prospecies’ or classic neoDarwinian ‘selfish genes’ selectively spreading through panmictic populations) can only be effectively understood by longer term monitoring of populations in the wild, to better capture rare evolutionary and ecological events and to better assess the efficacy of traditional microevolutionary processes. We believe that the resulting renaissance in macroevolutionary studies will encourage a broader systematic perspective ‐ one that better encompasses the remarkable diversity of evolutionary processes that together generated the present diversity of life.  相似文献   
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