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961.
Chunyan Zheng Fang Ouyang Xianghui Liu Junhua Ma Fenghua Zhao Zhu Ouyang Feng Ge 《Ecology and evolution》2019,9(19):11367-11378
Groundwater and nitrogen fertilizer overuse severely threatens crop productions; thus, current ecological agriculture requires low irrigation and nitrogen fertilizer inputs. The effects of combined reduced irrigation and nitrogen fertilizer addition on soil organism (e.g., mite) community and biodiversity remain poorly understood. We analyzed soil mite community composition, wheat grain yield, and soil characteristics in a 10‐year manipulation experiment with two levels of irrigation (reduced and conventional irrigation) and five nitrogen fertilizer levels (0, 70, 140, 210, and 280 kg N/ha). Reduced irrigation (20% reduction, from 280 to 220 mm) and nitrogen fertilizer (25% reduction, from 280 to 210 kg N/ha) addition did not significantly influence soil mite community and wheat yield. The relative abundances of fungivores and predators showed negative quadratic relationships with wheat yield, while that of plant parasites showed a positive relationship. The relationships between soil mite trophic groups and wheat yield revealed that we can evaluate the impacts of reduced irrigation and nitrogen fertilizer addition from the perspective of soil fauna. Soil mite community composition was altered by soil abiotic factors prior to reduced irrigation and nitrogen fertilizer addition. Overall, moderate reductions of irrigation and nitrogen fertilizer may not threaten to soil mite community and diversity or decrease crop production; in contrast, such reductions will benefit mite community development and the sustainable agriculture. 相似文献
962.
963.
采用PCR技术从鱼腥藻(Anabaena sp.) PCC 7120中扩增获得红色荧光蛋白基因all1280 gaf2,并利用Bam HⅠ和SalⅠ酶切位点,将该基因插入到pET-30a(+)中,构建表达载体pET-all1280 gaf2。将该表达载体与藻胆色素生物合成质粒pACYC-ho1-pcyA同时转化到大肠杆菌E. coli BL21 (DE3),表达后获得大肠杆菌色素细胞。结果显示,该色素细胞在荧光显微镜下具有红色荧光,且在15E/15Z态之间具有可逆光效应。进一步以pET-all1280 gaf2为模板,通过定点突变技术在all1280 gaf2基因中引入C53A突变,获得了突变体All1280 GAF2 (C53A)。将All1280 GAF2 (C53A)与藻胆色素在E. coli BL21 (DE3)中共表达,获得了比野生型红色荧光更强的大肠杆菌色素细胞。研究结果表明,与野生型相比,All1280 GAF2 (C53A)具有较高的摩尔消光系数和荧光量子产率,红色荧光更强。 相似文献
964.
目的探讨常见毛囊细胞角蛋白在毛囊周期中的表达特征。
方法取毛囊发育期、生长期启动、生长期、退化期和静止期的小鼠皮肤,石蜡切片后通过免疫荧光的方法,检测细胞角蛋白Krt5、Krt6、Krt10、Krt14、Krt15和Krt19的表达情况。
结果Krt5在静止期和生长期启动表达于所有毛囊上皮细胞,在其他时期表达不一致;Krt6表达于所有时期的外根鞘细胞和内根鞘细胞;Krt10表达于生长期和退化期的毛母质和内根鞘细胞,在其他时期表达不一致;Krt14在生长期和退化期表达于所有毛囊上皮细胞,在其他时期表达不一致;Krt15和Krt19表达于毛囊发育期、生长期启动和静止期的毛囊隆突区细胞,在生长期和退化期表达不一致。
结论角蛋白作为毛囊结构或毛囊干细胞标记物仅适用于特定的毛囊周期。研究者在使用毛囊角蛋白作为标记物时,应首先明确其在毛囊周期中的表达情况。 相似文献
965.
Zhenling Ma Xueli Zhao Mingjiao Deng Zhengjie Huang Jing Wang Yi Wu Dan Cui Yingfu Liu Rushi Liu Gaoliang Ouyang 《Cell reports》2019,26(6):1533-1543.e4
966.
967.
围产期干细胞库质量管理体系(QMS)建设是保障干细胞产品和服务健康发展的基础工作。本文比较分析美国输血协会(AABB)、细胞疗法认证基金会(FACT)和ISO 9001的标准的架构、内容和侧重点,重点论述围产期干细胞库QMS构建的方法、步骤和参考模式。参照权威机构标准建立和运行QMS,能够保障我国围产期干细胞库标准化、规范化和科学化的建设和管理,提升我国干细胞库能力和信任水平。良好的QMS进一步促进干细胞与精准医疗战略性新兴产业升级,为建设健康中国提供动力。 相似文献
968.
969.
Achyut Kumar Banerjee Hai‐Dan Wu Wu‐Xia Guo Wei‐Lun Ng Wei‐Xi Li Yan Ma Hui Feng Ye‐Lin Huang 《植物分类学报:英文版》2022,60(4):809-823
The phylogeography of coastal plant species is heavily influenced by past sealevel fluctuations, dispersal barriers, and life-history traits, such as long-distance dispersal ability of the propagules. Unlike the widely studied mangroves, phylogeographic patterns have remained mostly obscure for other coastal plant species. In this study, we sampled 42 populations of Scaevola taccada (Gaertn.) Roxb., a coastal shrub of the family Goodeniaceae, from 17 countries across its distribution range. We used five chloroplast DNA (cpDNA) and 14 nuclear microsatellite (simple sequence repeat [SSR]) markers to assess the influence of abiotic factors and population genetic processes on the phylogeographic pattern of the species. Geographical distribution of cpDNA haplotypes suggests that the species originated in Australia, followed by historical dispersal and expansion of its geographic range. Multiple abiotic factors, including the sealevel changes during the Pleistocene, the presence of landmasses like the Malay Peninsula, and contemporary oceanic circulation patterns, restricted gene flow between geographically distinct populations, thereby creating low haplotype diversity and a strong population structure. Population genetic processes acted on these isolated populations, leading to high nuclear genetic diversity and population differentiation, as revealed from analyzing the polymorphic SSR loci. Although genetic divergence was mostly concordant between cpDNA and SSR data, asymmetrical gene flow and ancestral polymorphism could explain the discordance in the detailed genetic structure. Overall, our findings indicate that abiotic factors and population genetic processes interactively influenced the evolutionary history and current phylogeographic pattern of S. taccada across its distribution range. 相似文献
970.
Gene duplication provides raw material for functional innovation, but gene duplicability varies considerably. Previous studies have found widespread asymmetrical sequence evolution between paralogs. However, it remains unknown whether the rate of evolution among paralogs affects their propensity of being retained after another round of whole-genome duplication (WGD). In this study, we investigated gene groups that have experienced two successive WGDs to determine which of two older duplicates with different evolutionary rates was more likely to retain both younger duplicates. To uncouple the measurement of evolutionary rates from any assignment of duplicate or singleton status, we measured the evolutionary rates of singleton genes in out-lineages but classified these singleton genes according to whether they are retained or not in a crown group of species. We found that genes that retained younger duplicates in the crown group of genomes were more constrained prior to the younger duplication event than those that failed to leave duplicates. In addition, we also found that the retained clades have more genes in out-lineages. Subsequent analyses showed that genes in the retained clades were expressed more broadly and highly than genes in the singleton clades. We concluded that the set of repeatedly retained genes after two WGDs is biased toward slowly evolving genes in angiosperms, suggesting that the potential of genes for both functional conservation and divergence likely affects their propensity of being retained after WGD in angiosperms. 相似文献