全文获取类型
收费全文 | 285篇 |
免费 | 24篇 |
专业分类
309篇 |
出版年
2022年 | 1篇 |
2021年 | 5篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 9篇 |
2013年 | 17篇 |
2012年 | 22篇 |
2011年 | 12篇 |
2010年 | 8篇 |
2009年 | 15篇 |
2008年 | 24篇 |
2007年 | 15篇 |
2006年 | 22篇 |
2005年 | 17篇 |
2004年 | 13篇 |
2003年 | 10篇 |
2002年 | 14篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 9篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 3篇 |
1971年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有309条查询结果,搜索用时 0 毫秒
301.
Partial phenylcarbamoylation of ribonucleosides by means of bis(tributyltin) oxide--phenyl isocyanate system is described herein; the reaction was found to occur regioselectively to give the corresponding 5'-, 3'-, and 2'-O-phenylcarbamoyl derivatives due to the conditions used. 相似文献
302.
Tomohisa Baba Takeshi Yoshida Yamato Tanabe Tatsunori Nishimura Soji Morishita Noriko Gotoh Atsushi Hirao Rikinari Hanayama Naofumi Mukaida 《Cell death & disease》2021,12(4)
Accumulating evidence indicates the presence of cytoplasmic DNAs in various types of malignant cells, and its involvement in anti-cancer drug- or radiotherapy-mediated DNA damage response and replication stress. However, the pathophysiological roles of cytoplasmic DNAs in leukemias remain largely unknown. We observed that during hematopoietic stem cell transplantation (HSCT) in mouse myeloid leukemia models, double-stranded (ds)DNAs were constitutively secreted in the form of extracellular vesicles (EVs) from myeloid leukemia cells and were transferred to the donor cells to dampen their hematopoietic capabilities. Subsequent analysis of cytoplasmic DNA dynamics in leukemia cells revealed that autophagy regulated cytoplasmic dsDNA accumulation and subsequent redistribution into EVs. Moreover, accumulated cytoplasmic dsDNAs activated STING pathway, thereby reducing leukemia cell viability through reactive oxygen species (ROS) generation. Pharmaceutical inhibition of autophagosome formation induced cytoplasmic DNA accumulation, eventually triggering cytoplasmic DNA sensing pathways to exert cytotoxicity, preferentially in leukemia cells. Thus, manipulation of cytoplasmic dsDNA dynamics can be a novel and potent therapeutic strategy for myeloid leukemias.Subject terms: Acute myeloid leukaemia, Chronic myeloid leukaemia 相似文献
303.
Unnatural bases specifically pairing with pyridin-2-one, 2-amino-6-(2-thienyl) purine and 2-amino-6-(2-furanyl)purine, were newly designed to replace 2-amino-6-(N,N-dimethylamino)purine. It was expected that these novel purine analogues, as compared with 2-amino-6-(N,N-dimethylamino)purine, might reduce the interference in the stacking interactions with the neighboring bases in a duplex and improve the efficiency of the enzymatic incorporation of the nucleoside triphosphate of pyridin-2-one opposite these unnatural bases. The syntheses of these nucleoside derivatives and the DNA fragments were examined. 相似文献
304.
Solid-phase synthesis of oligoribonucleotides 总被引:2,自引:0,他引:2
Selective deprotection of the 5'-O-dimethoxytrityl group of oligoribonucleotides required for 5'-deprotection reaction during synthesis of an oligoribonucleotide was achieved by the treatment with 1% dichloroacetic acid in dichloromethane at room temperature, without removal of the 2'-O-tetrahydropyranyl group. Phosphorylation of protected ribonucleosides and coupling reaction to the 5' end of oligoribonucleotides attached to polystyrene solid support were carried out by the use of bifunctional reagent 2-chlorophenyl-O-O-bis(1-benzotriazolyl) phosphate. In this way, trinucleotides; TpTpT, dUpdUpT, and UpUpT, were synthesized. 相似文献
305.
I Hirao T Fujiwara M Kimoto T Mitsui T Okuni T Ohtsuki S Yokoyama 《Nucleic acids symposium series》2000,(44):261-262
The unnatural base, 2-amino-6-(2-thienyl)purine (designated as s), instead of 2-amino-6-(N,N-dimethylamino)purine (designated as x), was designed in order to improve the specificity and efficiency of the base pairing with pyridin-2-one (designated as y). DNA fragments containing s were chemically synthesized, and the thermal stability and the enzymatic reactions involving the s-y pairing were examined. Thermal denaturation experiments showed that the DNA duplex (12-mer) containing the s-y pair was more stable than that containing the x-y pair. The incorporation of dyTP was also more advantageous to the s-y pairing than the x-y pairing in single-nucleotide insertion experiments using the Klenow fragment of Escherichia coli DNA polymerase I. 相似文献
306.
Y Takaue T Watanabe Y Kawano S Saitoh A Hirao K Matsunaga T Abe Y Kuroda T Ninomiya K Himeno 《Cellular immunology》1991,133(2):526-531
We report here the development of an alternative limiting dilution assay (LDA) of T lymphocytes (T cells). Blood mononuclear cells were first stimulated for 60 hr with PHA and then cultured in microwells in the presence of recombinant interleukin-2 without feeder cells. After 4 days of culture, wells were scored for proliferation. Clonal expansion of T cells followed the single-hit model of the Poisson distribution. The progenitor frequency (f) in the mononuclear cells and E-rosette-positive cells from normal donors were 0.082 +/- 0.025 (n = 12) and 0.236 +/- 0.029 (n = 5), respectively, but this was markedly decreased in patients who underwent marrow-ablative chemotherapy and autografts with blood hematopoietic stem cells. This LDA system should be of value in routine use for the evaluation of T cell proliferative activities. 相似文献
307.
Tomonori Hirao Atsushi Watanabe Manabu Kurita Teiji Kondo Katsuhiko Takata 《BMC plant biology》2008,8(1):70
Background
The recent determination of complete chloroplast (cp) genomic sequences of various plant species has enabled numerous comparative analyses as well as advances in plant and genome evolutionary studies. In angiosperms, the complete cp genome sequences of about 70 species have been determined, whereas those of only three gymnosperm species, Cycas taitungensis, Pinus thunbergii, and Pinus koraiensis have been established. The lack of information regarding the gene content and genomic structure of gymnosperm cp genomes may severely hamper further progress of plant and cp genome evolutionary studies. To address this need, we report here the complete nucleotide sequence of the cp genome of Cryptomeria japonica, the first in the Cupressaceae sensu lato of gymnosperms, and provide a comparative analysis of their gene content and genomic structure that illustrates the unique genomic features of gymnosperms. 相似文献308.
Susumu Yoshida Shigeo Kasuga Yuzo Hirao Tohru Fuwa Shizutoshi Nakagawa 《In vitro cellular & developmental biology. Plant》1987,23(7):460-464
Summary Biosynthetic human epidermal growth factor (Bh-EGF) induced dose-dependent synthesis and secretion of neutral mucin glycoprotein
when the fundal cells isolated from rabbit stomach were cultured in serum-free medium containing Bh-EGF at concentrations
as high as 10 to 100 ng/ml. At these high concentrations, Bh-EGF had no effect on the cell growth. In marked contrast, much
lower concentrations from 0.1 to 1.0 ng/ml of Bh-EGF failed to stimulate mucin synthesis, but enhanced proliferation of the
cells. Electrophoretic pattern of the mucin secreted from the cultured mucosal cells was very similar to that of the authentic
mucin obtained from rabbit stomach. Maximal secretion of the mucin from the cells was observed at Hour 96 of the culture.
Although fetal bovine serum (5%) and insulin (0.5 μg/ml) also stimulated the mucosal cells, both in growth and in mucin synthesis
and release, the enhancing activity of the mucin synthesized and released by Bh-EGF at a concentration of 100 ng/ml per microgram
DNA of cultured cells was far superior to that of 5% fetal bovine serum and 0.5 μg/ml insulin. 相似文献
309.
We found a synthetic GCGAAAGC fragment with a mobility greater than that of other oligodeoxyribonucleotides in gel electrophoresis to take on a stable hairpin structure possessing two terminal G-C base pairs. The GCGAAAGC sequence is also found in the replication origin of phage G4 single-stranded DNA, but the hairpin structure originally proposed differs from that of the GCGAAAGC fragment we have studied. Possibility of rearrangement of the secondary structure in the replication origin of phage G4 was examined in relation to its replication initiation mechanism. 相似文献