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991.
Gernot Segelbacher Per Wegge Andrey V. Sivkov Jacob H?glund 《Journal of Ornithology》2007,148(1):79-84
We quantified the genetic structure among 58 capercaillie (Tetrao urogallus) from three closely spaced leks in boreal Russia using ten microsatellite loci. We did not find significant structuring with
respect to lek membership in an overall analysis. However, all but one individual could be strongly assigned to one of two
genetic clusters, which we interpret as reflecting different local lineages or extended family groups. There was evidence
for structuring among some clusters within leks, and one smaller lek consisted of nine out of ten males from one cluster,
which could reflect kin biasing of lek membership. One cluster was apparently outperforming the other, since nine out of ten
juveniles sampled belonged to it. 相似文献
992.
Jakob Augustin Donald Blomqvist Tibor Szép Zoltán D. Szabó Richard H. Wagner 《Journal of Ornithology》2007,148(2):189-198
Genetic parentage studies of socially monogamous birds reveal a widespread prevalence of extra-pair paternity. Variation in
extra-pair paternity among individuals may depend on how different individuals benefit from extra-pair fertilisations and
on the opportunity to pursue extra-pair copulations. A long-term study of sand martins (Riparia riparia) in Hungary allowed us to examine patterns of extra-pair fertilisations in a large colony of over 3,000 breeding pairs with
many known age individuals. We used multi-locus DNA fingerprinting to determine whether extra-pair fertilisations occur when
females are paired to (1) presumably low quality mates, or (2) genetically similar or dissimilar mates, and whether extra-pair
fertilisations result in offspring of higher quality. Extra-paternal young were found in 38% of 47 broods and comprised 19%
of 190 offspring. Males that lost paternity did not differ significantly from others in age or body condition. Social mates
of broods containing extra-pair offspring did not differ in genetic similarity from pairs without extra-pair offspring. Furthermore,
there was no significant difference in body condition between extra-pair young and their maternal half-siblings. We were unable
to assign paternity and therefore cannot exclude the possibility that extra-pair males differed from the within-pair males
they cuckolded, in age, body condition or genetic similarity with the female. We found a positive relationship between paternity
losses and breeding density, suggesting that low breeding density may constrain opportunities for seeking extra-pair copulations. 相似文献
993.
Vagenas D Doeschl-Wilson A Bishop SC Kyriazakis I 《International journal for parasitology》2007,37(14):1617-1630
An in silico mathematical model was used to explore the effect of, and the interaction between, (i) nutrition, (ii) genotype for growth and (iii) genotype for resistance, on the estimates of genetic parameters for resistance and performance in a population of lambs trickle-challenged daily with 3,000 L3s of Teladorsagia circumcincta. A previously published model for nematode infections in sheep was developed to include heritable variation in sheep growth traits, as well as in immunologically controlled traits such as establishment of incoming larvae, mortality of the adult worms and fecundity of the adult female worms. The simulated population comprised 10,000 lambs, these being the offspring of 250 sires mated to 5,000 dams. The model assumed the lambs to be parasitologically naïve at weaning (2 months of age), at which point the trickle challenge commenced and the model was updated daily until slaughter (at 6 months of age). Dietary treatments included a good and a poor quality feed, offered ad libitum. Two genotypes for growth were assumed: (i) fast and (ii) slow growing. Three genotypes for resistance were used: (i) benchmark, (ii) susceptible and (iii) resistant, differing in their ability to cope with nematode infections. Genetic parameters for output traits, including growth rate, food intake, worm burden and faecal egg count were estimated using a linear mixed model, fitting sire as a random effect to capture genetic effects. Heritabilities and correlations were found to change over time. In general, the heritabilities of immunity traits increased over time, whereas genetic correlations between production and immunity traits became weaker. Diet had a significant effect on the means and the estimated correlations of output traits, while genotypes for growth and resistance had smaller effects. These results suggest that discrepancies between published genetic parameters for nematode resistance may be a function of environmental factors rather than differences in host genotype. 相似文献
994.
Zhang X Mahmudi-Azer S Connett JE Anthonisen NR He JQ Paré PD Sandford AJ 《Human genetics》2007,120(5):681-690
Polymorphonuclear leukocytes (PMNs) are major effector cells in the chronic airway inflammation in chronic obstructive pulmonary
disease (COPD). PMN degranulation is associated with degradation of extracellular matrix and tissue damage. Hck is an essential
molecule in the signaling pathway regulating PMN degranulation. We hypothesized that polymorphisms affect the expression level
of Hck, which, in turn, modulates PMN mediator release and tissue damage and influences the development of COPD. Here we systematically
investigated genetic tag polymorphisms of the Hck gene, Hck mRNA and protein expression pattern in PMNs, and PMN mediator release (myeloperoxidase) in 60 healthy white subjects, and
assessed their association with the use of several genetic models. The association of genetic polymorphisms with COPD-related
phenotypes was determined in the lung healthy study cohort (LHS). We identified a novel 15 bp insertion/deletion polymorphism
(8,656 L/S) in intron 1 of the Hck gene, which was associated with differential expression of Hck protein and PMN myeloperoxidase release. In the LHS cohort,
there was significant interaction between the 8,656 L/S polymorphism and smoking on baseline lung function and 8,656 L/S was
associated with bronchodilator response. These data suggest that the insertion/deletion polymorphism could be a functional
polymorphism of the Hck gene, may contribute to COPD pathogenesis and modify COPD-related phenotypes. 相似文献
995.
大豆异黄酮代谢途径在大肠杆菌中的构建及表达 总被引:1,自引:0,他引:1
自然界异黄酮合成途径主要存在于豆科植物中。以微生物为宿主研究异黄酮代谢,则需要将整个相关代谢途径的多酶体系组装到工程菌种,从而进行表达及代谢研究,这就需要用到多基因的转化和共表达技术。综合应用了多基因单载体和多基因多载体方法,将大豆异黄酮代谢途径中的五个关键酶基因导入到大肠杆菌中,对异黄酮代谢途径在大肠杆菌中的构建和表达进行了研究和探索,获得了含有五个外源基因的重组大肠杆菌;重组菌经IPTG诱导,以L-酪氨酸为底物进行发酵,发酵产物经过HPLC测定,结果表明和空白对照相比有新的代谢产物生成,初步断定为异黄酮类化合物。 相似文献
996.
997.
998.
野生动物资源是中医药业的主要物质基础之一。目前,生物多样性急剧下降,物种灭绝速度加快,许多药用野生动物濒临灭绝,严重阻碍了中医药业的可持续发展。在许多野生动物野外种群难以恢复或恢复速度很慢、寻找中医药动物原材料的替代品短期内难以实现的情况下,开辟中医药原材料来源渠道是促进中医药业可持续发展的主要措施之一。在正确认识野生动物保护与利用的关系的前提下,妥善、高效利用人工驯养繁殖、库存野生动物产品,遵循经济效益、社会效益、生态效益的原则,优先保障重点领域、重点产业的需要,并发挥市场配置资源的积极作用,充分实现有限资源的合理配置,以促进野生动物资源保护与中医药业可持续发展的良性循环。 相似文献
999.
随着基因芯片的技术的推广,越来越多的表达数据需要被处理和分析.利用这些表达数据提取基因调控矩阵从而构建基因网络是一个重要的问题.通过线性微分方程模型可以初步构建基因网络,了解网络结构,提取最显著的信息.然而由于分子生物学的条件限制或者数据来源的限制,导致实验数据不充分,使方程组无解.本文使用三次样条方法,对26例临床、病理资料完备的具有淋巴结转移的乳腺癌基因表达数据进行插值处理,使表达数据满秩,从而使用最小二乘法解出加权矩阵,构建初步的表达基因调控网络.通过对构建的基因网络的初步分析表明:乳腺癌转移的形成是由多基因异常引起多条传导通路异常,致使细胞恶性转化的结果,这与生物学上公认的看法是相一致的.因此,利用此线性模型方法对基因表达谱进行分析兵有一定可行性,在认识乳腺癌转移机制,乳腺癌诊断和治疗方面具有一定的理论和应用价值. 相似文献
1000.
Xiao-Jie Li Rie Uenishi Saiki Hase Huanan Liao Tee Kok Keng Shigeru Kusagawa Yutaka Takebe 《Virologica Sinica》2007,22(6):426-433
The Asia-Pacific region is a home to 60% of the population in the world and to approximately one quarter of people with HIV/AIDS. Close to a million of people has been infected and a half million people died of AIDS annually in Asia,becoming the second largest epicenter of global AIDS epidemic. Molecular epidemiology has been useful tool to track a course of HIV spread. In-depth knowledge from the studies on molecular epidemiology elucidates the dynamics of HIV spread and the interrelationship of epidemics in the different regions in Asia. 相似文献