首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   171篇
  免费   8篇
  179篇
  2023年   2篇
  2022年   4篇
  2021年   1篇
  2020年   3篇
  2019年   5篇
  2018年   4篇
  2017年   7篇
  2016年   11篇
  2015年   8篇
  2014年   2篇
  2013年   6篇
  2012年   8篇
  2011年   13篇
  2010年   6篇
  2009年   6篇
  2008年   8篇
  2007年   12篇
  2006年   19篇
  2005年   15篇
  2004年   13篇
  2003年   6篇
  2002年   5篇
  2001年   3篇
  2000年   5篇
  1999年   3篇
  1997年   2篇
  1985年   1篇
  1980年   1篇
排序方式: 共有179条查询结果,搜索用时 0 毫秒
141.
Tetrahydropyrimidine thiones, which are cyclic thiocarbamides derivatives, were synthesised from thiourea, β-diketones and substituted benzaldehydes. A tautomeric form of these derivatives incorporates the thiol functionality, which is known to interact with metal ions from metalloenzymes active sites, such as the carbonic anhydrases (CAs, EC 4.2.1.1) among others. This is a superfamily of widespread enzymes, which catalyses a crucial biochemical reaction, the reversible hydration of carbon dioxide to bicarbonate and protons (H+). The newly synthesised N-alkyl (aril)-tetrahydropyrimidine thiones were tested for inhibition of the cytosolic human isoforms I and II (hCA I and II). Both isoforms were effectively inhibited by the newly synthesised thiones. Ki values were in the range of 218.5?±?23.9–261.0?±?41.5?pM for hCA I, and of 181.8?±?41.9–273.6?±?41.4?pM for hCA II, respectively. This under-investigated class of derivatives may bring interesting insights in the field of non-sulphonamide CA inhibitors.  相似文献   
142.
C Polat 《Chronobiologia》1985,12(2):169-172
The possible rhythmic interaction between morphine and mast cell was investigated in mice. It has been found that both at normal and drug-induced state, mast cells varied as a function of time and the number of mast cells was significantly affected at the time in which the number of mast cells was highest over a 24-h period. The exact underlying mechanism of the phenomenon still remains to be investigated.  相似文献   
143.
The spindle position checkpoint (SPOC) is a mitotic surveillance mechanism in Saccharomyces cerevisiae that prevents cells from completing mitosis in response to spindle misalignment, thereby contributing to genomic integrity. The kinase Kin4, one of the most downstream SPOC components, is essential to stop the mitotic exit network (MEN), a signalling pathway that promotes the exit from mitosis and cell division. Previous work, however, suggested that a Kin4-independent pathway contributes to SPOC, yet the underlying mechanisms remain elusive. Here, we established the glycogen-synthase-kinase-3 (GSK-3) homologue Mck1, as a novel component that works independently of Kin4 to engage SPOC. Our data indicate that both Kin4 and Mck1 work in parallel to counteract MEN activation by the Cdc14 early anaphase release (FEAR) network. We show that Mck1''s function in SPOC is mediated by the pre-replication complex protein and mitotic cyclin-dependent kinase (M-Cdk) inhibitor, Cdc6, which is degraded in a Mck1-dependent manner prior to mitosis. Moderate overproduction of Cdc6 phenocopies MCK1 deletion and causes SPOC deficiency via its N-terminal, M-Cdk inhibitory domain. Our data uncover an unprecedented role of GSK-3 kinases in coordinating spindle orientation with cell cycle progression.  相似文献   
144.
Five cycloartane-type triterpene glycosides were isolated from the methanol extract of the roots of Astragalus amblolepis Fischer along with one known saponin, 3-O-β-D-xylopyranosyl-16-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane. Structures of the compounds were established as 3-O-β-D-xylopyranosyl-25-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane, 3-O-[β-D-glucuronopyranosyl-(1 → 2)-β-D-xylopyranosyl]-25-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane, 3-O-β-D-xylopyranosyl-24,25-di-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane, 6-O-α-L-rhamnopyranosyl-16,24-di-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane, 6-O-α-L-rhamnopyranosyl-16,25-di-O-β-D-glucopyranosyl-3β,6α,16β,24(S),25-pentahydroxy-cycloartane by using 1D and 2D-NMR techniques and mass spectrometry. To the best of our knowledge, the glucuronic acid moiety in cycloartanes is reported for the first time.  相似文献   
145.
146.
Neurochemical Research - In neonates supraphysiological oxygen therapy has been demonstrated to cause neuronal death in hippocampus, prefrontal cortex, parietal cortex, and retrosplenial cortex....  相似文献   
147.
148.
Inhibition of neuraminidase with neuraminic acid C-glycosides   总被引:2,自引:0,他引:2  
Neuraminic (sialic) acid based alpha-C-glycosides have been synthesized and their inhibitory activity towards bacterial neuraminidase (sialidase) was examined. While some C-glycosides were found to be potent inhibitors (Ki 15-30 microM) of this neuraminidase, others afforded no measurable activity. The structure-activity relationship of these C-glycosides is discussed in the context of other previously reported sialidase inhibitors.  相似文献   
149.
Akin M  Turgut S  Ayada C  Polat Y  Balci YI  Erdoğan F 《Gene》2011,487(1):80-83
The current study was conducted to assess 3435C>T multidrug resistance 1 gene polymorphism and the efficacy of high dose methylprednisolone (HDMP) in childhood acute idiopathic thrombocytopenic purpura patients.

Methods

A total of 31 childhood acute Idiopathic thrombocytopenic purpura patients (17 females, 14 males) between the ages of 2 and 16 years of age were included in the study. High-dose methylprednisolone was given at a dose of 30 mg/kg/day for 3 days and 20 mg/kg/day for 4 days, consecutively and intravenously. Polymerase chain reaction-restriction fragment length polymorphism was used for the detection of C3435T single nucleotide polymorphism. Fragments obtained were 238 bp to T/T genotype, 172 bp and 60 bp fragments to the C/C genotype, and 238 bp, 172 bp and 60 bp to the C/T genotype.

Results

The distribution of CC, CT, and TT genotypes were 19.0%, 61.3%, and 19.4%, respectively. Both allele frequencies of C and T were the same — 50%. There was no significant difference in genotype and allele distribution between the patients with ITP and the control group (χ2 = 0.84 p = 0.65, χ2 = 0.2 p = 0.63, respectively). There were no significant differences in age, gender, and pre- and post-treatment platelet counts between CC, CT, and TT genotypes of the MDR gene. Response to treatment shows no significant difference between genotype and allele groups.

Conclusion

In our study, there was no difference in the HDMP treatment response between MDR1 gene genotypes. However, it should be noted that this study includes a small group of patients. Our data should therefore be considered preliminary, awaiting further confirmatory studies on an expanded patient base.  相似文献   
150.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号