全文获取类型
收费全文 | 243篇 |
免费 | 31篇 |
国内免费 | 3篇 |
专业分类
277篇 |
出版年
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 16篇 |
2013年 | 14篇 |
2012年 | 20篇 |
2011年 | 19篇 |
2010年 | 12篇 |
2009年 | 17篇 |
2008年 | 9篇 |
2007年 | 10篇 |
2006年 | 13篇 |
2005年 | 15篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有277条查询结果,搜索用时 0 毫秒
11.
12.
Zhinxin Zhao Roberto Gambari Kenneth Ka-Ho Lee Stanton Hon-Lung Kok Raymond Siu-Ming Wong Fung-Yi Lau Johnny Cheuk-On Tang Kim-Hung Lam Chor-Hing Cheng Desmond Kwok Po Hau Chung-Hin Chui Wai-Yeung Wong Wai-Kwok Wong 《Bioorganic & medicinal chemistry letters》2013,23(8):2373-2376
We explore the possible cellular cytotoxic activity of an amphiphilic silicon(IV) phthalocyanine with axially ligated rhodamine B under ambient light experimental environment as well as its in vivo antitumour potential using Hep3B hepatoma cell model. After loading into the Hep3B hepatoma cells, induction of cellular cytotoxicity and cell cycle arrest were detected. Strong growth inhibition of tumour xenograft together with significant tumour necrosis and limited toxicological effects exerted on the nude mice could be identified. 相似文献
13.
14.
人精子顶体膜蛋白的纯化及性质的研究 总被引:2,自引:0,他引:2
目的:提取和纯化与人卵透明带(HZP)作用更为密切的人精子膜蛋白,为改进精子包被抗原的制备方法和筛选避孕疫苗抗原提供科学依据。方法:将人精子膜蛋白混合液进行SDS-PAGE电泳,然后全胶电洗脱分剐收集蛋白溶液30管,以阳性管内的HZP特异精子蛋白溶液包被抗原进行AsAb检测。结果:与HZP结合的人精子膜蛋白有多种成分;全胶电洗脱后以第14管内成分之特异最强,其分子量范围为48~53KD。结论:以电洗脱转移法纯化筛选的人精子膜蛋白是特异的,与HZP具极强相关性,可以用该精子膜蛋白包被抗原进行AsAb研究。 相似文献
15.
Differential contribution of inhibitory phosphorylation of CDC2 and CDK2 for unperturbed cell cycle control and DNA integrity checkpoints 总被引:6,自引:0,他引:6
Chow JP Siu WY Ho HT Ma KH Ho CC Poon RY 《The Journal of biological chemistry》2003,278(42):40815-40828
Inhibition of cyclin-dependent kinases (CDKs) by Thr14/Tyr15 phosphorylation is critical for normal cell cycle progression and is a converging event for several cell cycle checkpoints. In this study, we compared the relative contribution of inhibitory phosphorylation for cyclin A/B1-CDC2 and cyclin A/E-CDK2 complexes. We found that inhibitory phosphorylation plays a major role in the regulation of CDC2 but only a minor role for CDK2 during the unperturbed cell cycle of HeLa cells. The relative importance of inhibitory phosphorylation of CDC2 and CDK2 may reflect their distinct cellular functions. Despite this, expression of nonphosphorylation mutants of both CDC2 and CDK2 triggered unscheduled histone H3 phosphorylation early in the cell cycle and was cytotoxic. DNA damage by a radiomimetic drug or replication block by hydroxyurea stimulated a buildup of cyclin B1 but was accompanied by an increase of inhibitory phosphorylation of CDC2. After DNA damage and replication block, all cyclin-CDK pairs that control S phase and mitosis were to different degrees inhibited by phosphorylation. Ectopic expression of nonphosphorylated CDC2 stimulated DNA replication, histone H3 phosphorylation, and cell division even after DNA damage. Similarly, a nonphosphorylation mutant of CDK2, but not CDK4, disrupted the G2 DNA damage checkpoint. Finally, CDC25A, CDC25B, a dominant-negative CHK1, but not CDC25C or a dominant-negative WEE1, stimulated histone H3 phosphorylation after DNA damage. These data suggest differential contributions for the various regulators of Thr14/Tyr15 phosphorylation in normal cell cycle and during the DNA damage checkpoint. 相似文献
16.
We investigated the rat submaxillary gland for the presence of GnRH and GnRH receptors, the localization and colocalization of GnRH, GnRH receptor and their mRNA, and studied the sequence of GnRH receptor complementary DNA (cDNA) by immunohistochemistry, in situ hybridization and RT-PCR. The results showed that GnRH and GnRH receptor immunoreactive materials were colocalized in the epithelial cells of the serous acinus and glandular duct. The GnRH and GnRH receptor mRNA hybridization signals were detected in the above cells. The sequence obtained from the RT-PCR product was identical to the published cDNA sequence of GnRH receptor in the rat pituitary. The results suggested that the rat submaxillary gland was capable of synthesizing GnRH and GnRH receptors. GnRH may be involved in the functional regulation of the submaxillary gland through autocrine or paracrine activity. 相似文献
17.
The genus Ostreopsis is an important component of benthic and epiphytic dinoflagellate assemblages in coral reefs and seaweed beds of Malaysia.
Members of the species may produce toxins that contribute to ciguatera fish poisoning. In this study, two species have been
isolated and cultured, Ostreopsis ovata and Ostreopsis lenticularis. Analyses of the 5.8S subunit and internal transcribed spacer regions ITS1 and ITS2 of the ribosomal RNA gene sequences of
these two species showed that they are separate species, consistent with morphological designations. The nucleotide sequences
of the 5.8S subunit and ITS1 and ITS2 regions of the rRNA gene were also used to evaluate the interpopulation and intrapopulation
genetic diversity of O. ovata found in Malaysian waters. Results showed a low level of sequence divergence within populations. At the interpopulation level,
the rRNA gene sequence distinguished two groups of genetically distinct strains, representative of a Malacca Straits group
(isolates from Port Dickson) and a South China Sea group (isolates from Pulau Redang and Kota Kinabalu). Part of the sequences
in the ITS regions may be useful in the design of oligonucleotide probes specific for each group. Results from this study
show that the ITS regions can be used as genetic markers for taxonomic, biogeographic, and fine-scale population studies of
this species.
Received September 15, 2000; accepted December 15, 2000 相似文献
18.
不同功能位点介导α干扰素的免疫调节和中枢镇痛作用 总被引:6,自引:0,他引:6
细胞因子α干扰素(IFNα)具有中枢镇痛作用。抗内源性阿片肽血清与IFNα能发生明显的交叉反应,提示IFNα与内源性阿片肽之间存在着共同的抗原决定基。采用基因定点突变技术,获得系列IFNα突变体,并分别测定其免疫学活性和镇痛能力。结果显示,IFNα突变体Y129S-IFNα免疫学活性显著下降,但仍然保留了很强的镇痛能力,阿片受体拮抗纳洛酮能够阻断Y129S-IFNα的镇痛作用。实验结果表明,IFN 相似文献
19.
天花粉蛋白Y14F/R22L定点突变及其活性研究 总被引:1,自引:0,他引:1
利用多聚酶链式反应(PCR)技术,对天然天花粉蛋白(nTCS)基因在Tyr14和Arg22两个保守残基处同时进行定点突变,即Tyr14变成Phe,Arg22变成Leu,然后克隆到pET-8c高效表达载体上,构建成重组质粒pETY14F/R22L.经序列分析,定点突变的结果与预先设计的完全一致,突变后的天花粉蛋白命名为Y14F/R22LTCS.将pETY14F/R22L转化到E.coliBL21(DE3,pLysS)中,进行表达.经CM-SepharoseCL-6B柱纯化,SDS-PAGE鉴定,纯度可达90%.RIP活性测定显示,Y14F/R22LTCS的活性比nTCS降低了7.5倍,活性变化不显著,因此,TCS的Try14和Arg22对维持其活性部位构象并不是必需的.但由于Y14F/R22LTCS在E.coli中的表达量与nTCS相比明显下降,因此,Tyr14和Arg22可能与TCS翻译后的折叠有关. 相似文献
20.
Carbon‐Coated Li3Nd3W2O12: A High Power and Low‐Voltage Insertion Anode with Exceptional Cycleability for Li‐Ion Batteries 下载免费PDF全文
Rohit Satish Vanchiappan Aravindan Wong Chui Ling John B. Goodenough Srinivasan Madhavi 《Liver Transplantation》2014,4(9)
The synthesis of carbon‐coated Li3Nd3W2O12 (C‐Li3Nd3W2O12), a low voltage insertion anode (0.3 V vs. Li) for a Li‐ion battery, is reported to exhibit extraordinary performance. The low voltage reversible insertion provides an increase in the energy density of Li‐ion power packs. For instance, C‐Li3Nd3W2O12 delivered an energy density of ≈390 Wh kg?1 (based on cathode mass loading) when coupled with an LiMn2O4 cathode with an operating potential of 3.4 V. Furthermore, excellent cycling profiles are observed for C‐Li3Nd3W2O12 anodes both in half and full‐cell configurations. The full‐cell is capable of delivering very stable cycling profiles at high current rates (e.g., 2 C), which clearly suggests the high power capability of such garnet‐type anodes. 相似文献