全文获取类型
收费全文 | 574篇 |
免费 | 45篇 |
出版年
2018年 | 9篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 14篇 |
2013年 | 18篇 |
2012年 | 20篇 |
2011年 | 21篇 |
2010年 | 14篇 |
2009年 | 20篇 |
2008年 | 22篇 |
2007年 | 19篇 |
2006年 | 17篇 |
2005年 | 8篇 |
2004年 | 13篇 |
2003年 | 19篇 |
2002年 | 16篇 |
2001年 | 23篇 |
2000年 | 23篇 |
1999年 | 18篇 |
1998年 | 14篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 8篇 |
1994年 | 9篇 |
1993年 | 12篇 |
1992年 | 19篇 |
1991年 | 10篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 15篇 |
1987年 | 10篇 |
1986年 | 14篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 11篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 9篇 |
1974年 | 5篇 |
1973年 | 8篇 |
1971年 | 9篇 |
1970年 | 8篇 |
1968年 | 6篇 |
1967年 | 6篇 |
1966年 | 6篇 |
1965年 | 5篇 |
排序方式: 共有619条查询结果,搜索用时 531 毫秒
611.
612.
A S Wiharta H Hotta S Hotta T Matsumura M SujudiTsuji 《Microbiology and immunology》1985,29(4):337-348
Methylcellulose-elicited peritoneal macrophages from BALB/c mice were cultivated in vitro and inoculated with dengue virus (DV). At intervals thereafter portions of the culture fluids were taken and titrated for viral infectivity. Extracts from Ascaris suum and Parascaris equorum, either crude or Sephadex G-100 fractionated, were examined for effects on the multiplication of DV. The macrophage cultures treated with the above substances produced larger amounts of DV compared with untreated control cultures. The enhancing effect of the substances depended on doses added and duration of treatment and was suppressed by co-treatment with carrageenan, a specific macrophage-inhibiting agent, but was not related to the viability of cultured cells. In fluorescent antibody (FA) as well as infectious center assay experiments, it was shown that the DV-infected cells were found more frequently in treated cultures than in untreated control cultures. In the treated cultures phagocytosis by cultured cells was also of a higher magnitude than that in untreated cultures. In cocultures of macrophages and splenocytes from the same line of mice, no additive effect of splenocytes was noted. The limulus amebocyte lysate clotting enzyme reaction (Limulus test) indicated that involvement of bacterial lipopolysaccharides in the enhancement phenomena was negligible. The data so far obtained suggest that the enhancing effect was due to direct action of the parasitic extracts on macrophages. Four Sephadex G-100 fractions from the crude extracts showed similar activities; however, the effects of fractions I and III appeared to be comparatively strong. Significance of the findings in relation to the pathogenesis of DV infection was discussed. 相似文献
613.
The present report describes not only the effects of tannic acid (TA; belonging to hydrolyzable tannins) and its related compounds upon the infectivity of Chikungunya virus (CHIKV) but also the mechanism involved in this phenomenon. Our data show that TA inactivates CHIKV in vitro. Since the inactivating effect turned out to be pH-dependent and was suppressed by bovine serum albumin, it is most probable that the virus-inactivating capacity of TA is attributable to its preferential binding to proteins of virus particles. Examination on the virus-inactivating capacities of some TA-related compounds and comparison of their structures indicated that the active site of TA and its analogues might be the phenolic hydroxyl groups in their molecules. It seems that the active groups interact with the proteins of virus particles, resulting in a reduction or loss of viral infectivity. Discussion is made on the specificity of the actions of tannins and the possibility of application thereof to chemicals which are useful to investigate the nature and properties of viral proteins. 相似文献
614.
H Stern Y Hotta 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》1977,277(955):277-294
The process of meiosis in Lilium falls into four physiological stages - prezygotene, zygotene, pachytene, and post-pachytene. Each of these stages has distinctive metabolic characteristics. Commitment to meiosis occurs during the prezygotene interval at about the time when S-phase replication is completed. The activities following commitment are essential to synapsis inasmuch as perturbations of cells during that interval have subsequent effects on synapsis and crossing over. Just before the initiation of synapsis, a distinctive lipoprotein complex appears in the nucleus. The complex most probably functions in the process of pairing. Zygotene is marked by the delayed replication of specific intercalary segments of chromosomal DNA (Z-DNA), the replication being a necessary condition for ongoing synapsis. The replication occurs in the lipoprotein complex in the presence of a reassociation protein (r-protein). Z-DNA segments would appear to have other meiotic functions inasmuch as the replicated segments remain unligated to the body of chromosomal DNA until the beginning of chromosome disjunction. The pachytene interval is marked by an activation of endonucleolytic activity. The enzyme produces single-stranded nicks in the DNA at specific loci. These loci consist of moderately repeated segments; about 100-200 base pairs long. Extracellular agents, such as radiation, cause random nicking regardless of the meiotic stage at which they are applied. Localized nicking and repair are thus unique features of meiosis. The temporal segregation of metabolic activities concerned with pairing and crossing over and their operation in special chromosome regions constitute the most prominent features of the biochemical events associated with meiosis. 相似文献
615.
616.
617.
618.
Chatchawann Apichartpiyakul Hirofumi Miyajima Hisaya Doi Masashi Mizokami Morio Homma Hak Hotta 《Microbiology and immunology》1995,39(4):285-289
By means of a polymerase chain reaction (PCR) method using subtype-specific primers for hepatitis C virus (HCV) subtypes 1a, 1b, 2a, 2b and 3a, the prevalence of each subtype among HCV isolates in Chiang Mai, Thailand, was determined. HCV-3a appeared to be the most common subtype in blood donors, and was also frequently found in patients with liver disease. HCV-1b, but not HCV-2a or ?2b, was also commonly found in this area, while a considerable percentage of the total HCV isolates still remained unclassifiable by the above methods. Serotype analysis of the HCV isolates using C14-1 and C14-2 recombinant peptides revealed that HCV-3a was likely to carry an antigenic determinant(s) different from those of the major types 1 (HCV-1a and ?1b) and 2 (HCV-2a and ?2b). 相似文献
619.