全文获取类型
收费全文 | 221篇 |
免费 | 7篇 |
国内免费 | 5篇 |
专业分类
233篇 |
出版年
2023年 | 8篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 9篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 9篇 |
2013年 | 21篇 |
2012年 | 13篇 |
2011年 | 13篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 6篇 |
2007年 | 10篇 |
2006年 | 6篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1992年 | 7篇 |
1991年 | 1篇 |
1990年 | 5篇 |
1989年 | 11篇 |
1988年 | 5篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有233条查询结果,搜索用时 0 毫秒
101.
Zarrin Banikazemi Hemat Aghagolzadeh Haji Mohsen Mohammadi Gholamreza Taheripak Elmira Iranifar Mohsen Poursadeghiyan Abdullah Moridikia Bahman Rashidi Mohsen Taghizadeh Hamed Mirzaei 《Journal of cellular biochemistry》2018,119(1):185-196
Cancer is one of main health public problems worldwide. Several factors are involved in beginning and development of cancer. Genetic and internal/external environmental factors can be as important agents that effect on emerging and development of several cancers. Diet and nutrition may be as one of important factors in prevention or treatment of various cancers. A large number studies indicated that suitable dietary patterns may help to cancer prevention or could inhibit development of tumor in cancer patients. Moreover, a large numbers studies indicated that a variety of dietary compounds such as curcumin, green tea, folat, selenium, and soy isoflavones show a wide range anti‐cancer properties. It has been showed that these compounds via targeting a sequence of cellular and molecular pathways could be used as suitable options for cancer chemoprevention and cancer therapy. Recently, dietary microRNAs and exosomes have been emerged as attractive players in cancer prevention and cancer therapy. These molecules could change behavior of cancer cells via targeting various cellular and molecular pathways involved in cancer pathogenesis. Hence, the utilization of dietary compounds which are associated with powerful molecules such as microRNAs and exosomes and put them in dietary patterns could contribute to prevention or treatment of various cancers. Here, we summarized various studies that assessed effect of dietary patterns on cancer prevention shortly. Moreover, we highlighted the utilization of dietary compounds, dietary microRNAs, and dietary exosomes and their cellular and molecular pathways in cancer chemoprevention. 相似文献
102.
对紫玉盘属8种,杯冠木属3种和Ellipeia属 1种进行了叶的比较研究,以调查不同种之间解剖 学的不同点,这对种的鉴别和了解它们的分类学意义可能是有用的。有意义的解剖学特征是:末端石细 胞,表皮细胞的晶簇,毛状体,在中脉和叶柄的薄壁组织内的短石细胞以及中脉和叶柄横切面的形状。 有某些特征仅出现在某些种中,这对种的鉴别是有用的。结果亦显示这三个属的联系十分紧密。 相似文献
103.
Louise K. Sj?holm Lena Backlund Emarndeena Haji Cheteh Inger R?mer Ek Louise Frisén Martin Schalling Urban ?sby Catharina Lavebratt Pernilla Nikamo 《PloS one》2010,5(9)
Background
Bipolar disorder patients often display abnormalities in circadian rhythm, and they are sensitive to irregular diurnal rhythms. CRY2 participates in the core clock that generates circadian rhythms. CRY2 mRNA expression in blood mononuclear cells was recently shown to display a marked diurnal variation and to respond to total sleep deprivation in healthy human volunteers. It was also shown that bipolar patients in a depressive state had lower CRY2 mRNA levels, nonresponsive to total sleep deprivation, compared to healthy controls, and that CRY2 gene variation was associated with winter depression in both Swedish and Finnish cohorts.Principal Findings
Four CRY2 SNPs spanning from intron 2 to downstream 3′UTR were analyzed for association to bipolar disorder type 1 (n = 497), bipolar disorder type 2 (n = 60) and bipolar disorder with the feature rapid cycling (n = 155) versus blood donors (n = 1044) in Sweden. Also, the rapid cycling cases were compared with bipolar disorder cases without rapid cycling (n = 422). The haplotype GGAC was underrepresented among rapid cycling cases versus controls and versus bipolar disorder cases without rapid cycling (OR = 0.7, P = 0.006−0.02), whereas overrepresentation among rapid cycling cases was seen for AAAC (OR = 1.3−1.4, P = 0.03−0.04) and AGGA (OR = 1.5, P = 0.05). The risk and protective CRY2 haplotypes and their effect sizes were similar to those recently suggested to be associated with winter depression in Swedes.Conclusions
We propose that the circadian gene CRY2 is associated with rapid cycling in bipolar disorder. This is the first time a clock gene is implicated in rapid cycling, and one of few findings showing a molecular discrimination between rapid cycling and other forms of bipolar disorder. 相似文献104.
Fructus Euphorbia sororia is a widely used traditional medicine in China. Six new jatrophane-type diterpenoids (compounds 1–6) were isolated from Fructus E. sororia. The structures were elucidated by spectroscopic methods (IR, ESI-MS, HR-ESI-MS, 1D and 2D NMR). 相似文献
105.
In the present study, a new online monitoring method for the determination of the CO? sensitivity of micro-organisms, based on the values of the respiration factors [OTR (oxygen transfer rate) and CTR (carbon dioxide transfer rate)], obtained by using the RAMOS (respiratory activity monitoring system) device considering a variety of aeration rates in the measuring flask, is investigated. Based on the data of the OTR, obtained by RAMOS under a variety of specific aeration rates, the proposed new method was developed as an online monitoring method for CO? sensitivity of micro-organisms in shaken bioreactors. A maximum accumulated CO? concentration of 12% was derived in applied methods, provided that the cultivation system is carried out under optimal conditions. Additionally, to predict these conditions, an unsteady-state gas transfer model in shaken bioreactors would be very advantageous. The data of OTR obtained using the RAMOS device were analysed and recalculated by a programme considering the calibration factor (Cf). The major advantage of the new method is the possibility to determine the metabolic activity, regardless of manual sampling. 相似文献
106.
Haji Gholi Kami 《Zoology in the Middle East.》2013,59(1):67-70
Abstract Three specimens of the Olive Ridley Turtle (Lepidochelys olivacea) were collected in Guader (Gwatar) Bay in the Sea of Oman on 6 January, 1997. Two of them have been preserved for the Zoological Museum of Gorgan University. This is the first report of the Olive Ridley Turtle in Iranian coastal waters. 相似文献
107.
Abadi RH 《Indian journal of biochemistry & biophysics》2003,40(3):209-212
In this paper, analysis of free nucleotides from mouseliver tissue during different day times has been described. Perchloric acid extract of mouse liver tissue was neutralized with tri-N-octylamine in trichlorotriflouroethane and after removal of ClO4(-), subjected to preliminary purification on a Cu(2+)-loaded column of Chelex 100. A high-pressure liquid chromatographic (HPLC) anion-exchange procedure used in the study gave a good resolution of free nucleotides on a single column. 相似文献
108.
109.
Characeae, a family of calcifying green algae, are common in carbonate-rich freshwaters. The southwestern shoreline of Lake Ganau (Kurdistan Region, northeastern Iraq) harbors dense and thick mats of these algae (genus Chara). On the lake bottom and along the shore, carbonate sands and rocks rich in the remains of stems, branches, nodes, and whorls of Chara are deposited. These deposits show all stages of growth and degradation of characean algae, including replacement and lithification into limestone. The replacement of the fragments by fine-grained calcite preserved delicate microstructures of Chara, such as cortical walls, cell shape, inner and outer layers of the stems, and reproductive organs. Based on roundness, sorting, the degree of lithification, and preserved microstructures of the grains (fragments), three facies were recognized. The first is represented by a newly formed lime sand facies showing elongated grains, poor sorting, and reduced roundness, with pristine preservation of characean surface microstructures. The second is a weathered lime sand facies, which shows better sorting and good roundness, whereas internal structures of characean fragments are still well preserved. The third is comprised of a lithified lime sand facies (grainstone), with very well sorted and rounded grains, and poorly preserved external and internal structures of the characeans. As compared to the newly formed lime sand facies, the grainstone facies shows an increase in grain size by more than 30 %, owing to precipitation of micritic lamina of possible microbial origin. Eventually, the Characeae-derived lime sands are lithified into oolitic limestones with sparry calcite cement, forming a grainstone microfacies. The present study has important implications for the interpretation of pre-Quaternary environments, as it records all stages of the fossilization process of characean green algae and highlights the role of these algae in the formation of oolitic carbonate rocks. 相似文献
110.
The Bicoid (Bcd) protein gradient in Drosophila serves as a paradigm for gradient formation in textbooks. To explain the generation of the gradient, the ARTS model, which is based on the observation of a bcd mRNA gradient, proposes that the bcd mRNA, localized at the anterior pole at fertilization, migrates along microtubules (MTs) at the cortex to the posterior to form a bcd mRNA gradient which is translated to form a protein gradient. To fulfil the criteria of the ARTS model, an early cortical MT network is thus a prerequisite. We report hitherto undiscovered MT activities in the early embryo important for bcd mRNA transport: (i) an early and omnidirectional MT network exclusively at the anterior cortex of early nuclear cycle embryos showing activity during metaphase and anaphase only, (ii) long MTs up to 50 µm extending into the yolk at blastoderm stage to enable basal-apical transport. The cortical MT network is not anchored to the actin cytoskeleton. The posterior transport of the mRNA via the cortical MT network critically depends on maternally-expressed αTubulin67C and the minus-end motor Ncd. In either mutant, cortical transport of the bcd mRNA does not take place and the mRNA migrates along another yet undisclosed interior MT network, instead. Our data strongly corroborate the ARTS model and explain the occurrence of the bcd mRNA gradient. 相似文献