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91.
Autopolyploidization is considered to play an important role in plant evolution. In polyploidization, the polyploid evolves from the original diploid cytotype, in which the triploid state is considered to mediate the process (triploid bridge). Nevertheless, the fitness of triploid individuals seems to be too low to facilitate the polyploidization process (triploid block). The evolutionary condition of autopolyploidy was analyzed using a mathematical model focusing on the role of parthenogenesis in triploid and tetraploid individuals. In addition, offspring were assumed to arise by sexual reproduction by conjugations between haploid, diploid, and triploid gametes produced by diploid, tetraploid, and triploid individuals. According to the analysis, even if triploid block suppresses the fitness of sexually produced triploids, the polyploidization process can proceed when parthenogenesis occurs frequently. If only triploids frequently reproduce parthenogenetically, the evolutionary consequences tend to depend on the fitness of the tetraploid individuals. On the basis of a predetermined parameter set, if tetraploid fitness is relatively low, all three ploidies can coexist. Otherwise, tetraploidization occurs. In this case, triploid parthenogenesis promotes not only triploidization but also tetraploidization. However, if both triploids and tetraploids frequently reproduce parthenogenetically, the ploidy levels with the highest fitness are likely to dominate in the population through direct competition among cytotypes. 相似文献
92.
93.
Nicholas M. Thomson Azusa Saika Kazunori Ushimaru Smith Sangiambut Takeharu Tsuge David K. Summers Easan Sivaniah 《Applied and environmental microbiology》2013,79(6):1948-1955
The type I polyhydroxyalkanoate synthase from Cupriavidus necator was heterologously expressed in Escherichia coli with simultaneous overexpression of chaperone proteins. Compared to expression of synthase alone (14.55 mg liter−1), coexpression with chaperones resulted in the production of larger total quantities of enzyme, including a larger proportion in the soluble fraction. The largest increase was seen when the GroEL/GroES system was coexpressed, resulting in approximately 6-fold-greater enzyme yields (82.37 mg liter−1) than in the absence of coexpressed chaperones. The specific activity of the purified enzyme was unaffected by coexpression with chaperones. Therefore, the increase in yield was attributed to an enhanced soluble fraction of synthase. Chaperones were also coexpressed with a polyhydroxyalkanoate production operon, resulting in the production of polymers with generally reduced molecular weights. This suggests a potential use for chaperones to control the physical properties of the polymer. 相似文献
94.
Ali Ferjani Shoji Segami Gorou Horiguchi Azusa Sakata Masayoshi Maeshima Hirokazu Tsukaya 《Plant signaling & behavior》2012,7(1):38-42
The synthesis of DNA, RNA, and de novo proteins is fundamental for early development of the seedling after germination, but such processes release pyrophosphate (PPi) as a byproduct of ATP hydrolysis. The over-accumulation of the inhibitory metabolite PPi in the cytosol hinders these biosynthetic reactions. All living organisms possess ubiquitous enzymes collectively called inorganic pyrophosphatases (PPases), which catalyze the hydrolysis of PPi into two orthophosphate (Pi) molecules. Defects in PPase activity cause severe developmental defects and/or growth arrest in several organisms. In higher plants, a proton-translocating vacuolar PPase (H+PPase) uses the energy of PPi hydrolysis to acidify the vacuole. However, the biological implications of PPi hydrolysis are vague due to the widespread belief that the major role of H+PPase in plants is vacuolar acidification. We have shown that the Arabidopsis fugu5 mutant phenotype, caused by a defect in H+PPase activity, is rescued by complementation with the yeast cytosolic PPase IPP1. In addition, our analyses have revealed that increased cytosolic PPi levels impair postgerminative development in fugu5 by inhibiting gluconeogenesis. This led us to the conclusion that the role of H+PPase as a proton-pump is negligible. Here, we present further evidence of the growth-boosting effects of removing PPi in later stages of plant vegetative development, and briefly discuss the biological role of PPases and their potential applications in different disciplines and in various organisms. 相似文献
95.
Masaaki Murakami Masaya Harada Daisuke Kamimura Hideki Ogura Yuko Okuyama Noriko Kumai Azusa Okuyama Rajeev Singh Jing-Jing Jiang Toru Atsumi Sayaka Shiraya Yuji Nakatsuji Makoto Kinoshita Hitoshi Kohsaka Makoto Nishida Saburo Sakoda Nobuyuki Miyasaka Keiko Yamaguchi-Takihara Toshio Hirano 《Cell reports》2013,3(3):946-959
Highlights? The IL-6 amplifier is associated with various human diseases and disorders ? Genome-wide screens can isolate IL-6-amplifier-related genes ? These genes include those associated with human diseases ? Identified genes, e.g., the epiregulin-ErbB1 axis, may be therapeutic targets 相似文献
96.
Yoko Komada Yuko Ikeda Makoto Sato Azusa Kami Chika Masuda Shigenobu Shibata 《Chronobiology international》2019,36(2):258-264
Menstrual symptoms may have a significant impact on women’s lives. Many women experience menses-related health problems, such as menstrual pain, heavy menstrual bleeding, and premenstrual syndrome, during their reproductively fertile years. Circadian misalignment in shift workers has been reported to contribute to menstrual cycle irregularity and/or painful menstruation. However, the relationship between social jetlag (SJL) and menstrual symptoms/menstrual cycle has not been elucidated. In this study, we aimed to elucidate this relationship among female university students. One-hundred and fifty female university students (mean [SD]: 18.8 [0.71]-years old) completed self-reported questionnaires consisting of menstrual symptoms and menstrual cycle, sleep quality and sleep habits, quality of life, and demographic variables. The average menstrual cycle was 32.0 [5.4] days. The percentage of students who showed menstrual cycle irregularity, having less than 25 days or more than 39 days of menstrual cycle during the previous four menstrual cycles, was 60.6%. SJL, the difference between mid-sleep time on free days and mid-sleep time on school days, was categorized into small (absolute SJL < 1 h) or large (≥1 h). Overall, 78.0% of participants had SJL ≥ 1 h. Among the menstrual symptoms, pain, behavioral change, and water retention subscale scores were significantly higher in the SJL ≥ 1 h group than in the SJL < 1 h group. However, no significant differences were found in concentration, autonomic reaction, or negative affect subscale scores between the two groups. The menstrual cycle was 31.2 [5.5] days in the SJL < 1 h group and 32.2 [5.4] days in the SJL ≥ 1 h group, without significant difference. Logistic regression analysis showed that more than 1 h of SJL was a significant associated factor with severe menstrual symptom, independently of sleep duration and late chronotype. This study indicated that SJL was a significant factor associated with severe menstrual symptoms, suggesting the possibilities of association between circadian system and reproductive function among humans. 相似文献
97.
Nobuyuki Mase Azusa Inoue Masaki Nishio Kunihiko Takabe 《Bioorganic & medicinal chemistry letters》2009,19(14):3955-3958
Optically active lactones are important synthons in perfume and aroma manufacturing. Therefore, developments of efficient asymmetric syntheses are desired. Organocatalytic asymmetric α-hydroxymethylations of cyclopentanone with aqueous formaldehyde have been developed, to furnish the corresponding α-(hydroxymethyl)cyclopentanone with high enantioselectivity. Further chemical transformation of α-(hydroxymethyl)cyclopentanone gave the key intermediate for jasmine lactone, which is widely found in fruits and flowers. 相似文献
98.
Chromosomal instability in human mesenchymal stem cells immortalized with human papilloma virus E6, E7, and hTERT genes 总被引:2,自引:0,他引:2
99.
Qing-Hua Yuan Azusa Tanaka Richard H. Kaszynski Morio Iino Tomoko Okuno Tatsuaki Tsuruyama Toshimichi Yamamoto Alec J. Jeffreys Keiji Tamaki 《Journal of molecular evolution》2009,68(2):126-133
Lineages of structurally related alleles at minisatellite MS32 in human populations show considerable differentiation at the continental level. However, the regional specificity of these lineages remains unknown. We now describe the comparison of allele structures in Thai, Han Chinese, and Japanese populations with lineages previously established for North Europeans and Africans. The great majority of alignable Asian alleles showed their closest structural relative in Asia, with few instances of preferential alignment of Asian with European alleles and only one isolated incident showing a best match with an African allele. Further, there was a strong tendency, most marked for Japanese, for Asian alleles to align preferentially with other alleles from the same population, indicating strong regional specificity of allele lineages. This rapidly evolving minisatellite can therefore serve as a lineage marker for exploring recent events in human population history and dissecting population structure at the fine-scale level, as well as being an extremely informative DNA marker for personal identification. 相似文献
100.
Kei Asayama Lutgarde Thijs Jana Brguljan-Hitij Teemu J. Niiranen Atsushi Hozawa José Boggia Lucas S. Aparicio Azusa Hara Jouni K. Johansson Takayoshi Ohkubo Christophe Tzourio George S. Stergiou Edgardo Sandoya Ichiro Tsuji Antti M. Jula Yutaka Imai Jan A. Staessen for the International Database of Home Blood Pressure in Relation to Cardiovascular Outcome investigators 《PLoS medicine》2014,11(1)