全文获取类型
收费全文 | 244篇 |
免费 | 23篇 |
国内免费 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 16篇 |
2014年 | 11篇 |
2013年 | 17篇 |
2012年 | 21篇 |
2011年 | 19篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 13篇 |
2007年 | 16篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 12篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1994年 | 1篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1969年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1962年 | 1篇 |
1953年 | 1篇 |
排序方式: 共有268条查询结果,搜索用时 46 毫秒
121.
122.
Pedro Tauler Antoni Aguiló Isabel Gimeno Aina Noguera Alvar Agustí Josep A. Tur 《Free radical research》2013,47(9):931-938
We have determined the effects of chronic vitamin C intake on neutrophil and lymphocyte antioxidant defences during the acute phase immune response induced by intense exercise. Blood samples were taken from 16 voluntary athletes in basal conditions, both immediately after and 1 h after a duathlon competition. Sportsmen's nutrient intakes were determined before the competition. After determining the basal plasmatic ascorbate levels, the results were analysed taking into account the vitamin C intake and their plasmatic levels. Two groups were constituted, the vitamin C supplemented group and the control group, with the dietary vitamin C intake as the only statistical difference between groups. The duathlon competition induced a significant neutrophilia, which was higher in the supplemented group. Lymphocyte antioxidant enzyme activities increased after the competition, with a higher increase in SOD activity in the control group than in the supplemented one. The competition decreased neutrophil antioxidant enzyme activities and neutrophil ascorbate concentration. The decrease in the SOD activity in the supplemented group was higher than in the control group. Finally, the duathlon competition increased the expression of MAC-1 neutrophil adhesion molecule in the supplemented group. High vitamin C intake influenced the response of neutrophils and lymphocytes to oxidative stress induced by exercise, increasing the neutrophil activation. 相似文献
123.
124.
Leendertz FH Scuda N Cameron KN Kidega T Zuberbühler K Leendertz SA Couacy-Hymann E Boesch C Calvignac S Ehlers B 《Journal of virology》2011,85(2):916-924
The oncogenic Merkel cell polyomavirus (MCPyV) infects humans worldwide, but little is known about the occurrence of viruses related to MCPyV in the closest phylogenetic relatives of humans, great apes. We analyzed samples from 30 wild chimpanzees and one captive gorilla and identified two new groups of polyomaviruses (PyVs). These new viruses are by far the closest relatives to MCPyV described to date, providing the first evidence of the natural occurrence of PyVs related to MCPyV in wild great apes. Similar to MCPyV, the prevalence of these viruses is relatively high (>30%). This, together with the fact that humans in West and Central Africa frequently hunt and butcher primates, may point toward further MCPyV-like strains spreading to, or already existing in, our species. 相似文献
125.
Peach softening is usually attributed to the dismantling of the cell wall in which endo-polygalacturonase (endo-PG)-catalysed depolymerization of pectins plays a central role. In this study, the hypothesis that the function of endo-PG is critical for achieving a melting flesh fruit texture but not for reducing fruit firmness was tested by comparing pericarp morphology and endo-PG expression and localization in melting (MF) and non-melting flesh (NMF) fruit at successive stages of ripening. MF Bolero, Springbelle, and Springcrest, and NMF Oro-A and Jonia cultivars were analysed. Both MF and NMF fruit were left to ripen on the tree and reached a firmness of <10 Newtons (N). The image analysis of pericarp tissues revealed that during softening the loss of cell turgidity was a process common to mesocarp cells of all MF and NMF fruit and was clearly visible in peaches with a firmness of less than ~20?N. In contrast, the loss of cell adhesion was a feature exclusively observed in ripe MF fruit pericarp. In this ripe fruit, large numbers of endo-PG isoforms were highly expressed and the enzyme localization corresponded to the middle lamella. As a consequence, wide apoplastic spaces characterized the pericarp of ripe MF peaches. In contrast, no loss of cell adhesion was observed in any NMF fruit or in unripe MF peaches. Accordingly, no endo-PG was detected in unripe NMF fruit, whereas few and poorly expressed enzyme isoforms were revealed in ripe NMF and in unripe MF peaches. In this fruit, the poorly expressed endo-PG localized mainly in vesicles within the cytoplasm and inner primary cell wall. On the whole the results suggested that endo-PG function was needed to achieve melting flesh texture, which was characterized by wide apoplastic spaces and partially deflated mesocarp cells. Conversely, endo-PG activity had no critical influence on the reduction of fruit firmness given the capacity of NMF peaches to soften, reaching values of 5-10?N. As in tomato, the change of symplast/apoplast water status seems to be the main process through which peach fruit regulates its firmness. 相似文献
126.
目的 构建和鉴定Hoxa11和EGFP双基因共表达真核载体.方法 采用DNA重组技术,将目的 基因Hoxa11克隆至含有报告基因EGFP的pEGFP-N1真核表达载体中,构建的真核表达载体pEGFP-Hoxa11经PCR,双酶切及基因测序鉴定;转染至CHO细胞,荧光显微镜下观察重组质粒的表达,提取细胞蛋白Western印迹检测蛋白表达.结果 pEGFP-Hoxa11重组质粒构建成功.构建的真核表达载体pEGFP-Hoxa11能在CHO细胞中有效表达.结论 成功构建了共表达Hoxa11和EGFP的真核表达载体,并能在CHO细胞中有效表达.为进一步研究Hoxa11的功能提供实验基础. 相似文献
127.
Jessen N An D Lihn AS Nygren J Hirshman MF Thorell A Goodyear LJ 《American journal of physiology. Endocrinology and metabolism》2011,301(1):E164-E171
Exercise and weight loss are cornerstones in the treatment and prevention of type 2 diabetes, and both interventions function to increase insulin sensitivity and glucose uptake into skeletal muscle. Studies in rodents demonstrate that the underlying mechanism for glucose uptake in muscle involves site-specific phosphorylation of the Rab-GTPase-activating proteins AS160 (TBC1D4) and TBC1D1. Multiple kinases, including Akt and AMPK, phosphorylate TBC1D1 and AS160 on distinct residues, regulating their activity and allowing for GLUT4 translocation. In contrast to extensive rodent-based studies, the regulation of AS160 and TBC1D1 in human skeletal muscle is not well understood. In this study, we determined the effects of dietary intervention and a single bout of exercise on TBC1D1 and AS160 site-specific phosphorylation in human skeletal muscle. Ten obese (BMI 33.4 ± 2.4, M-value 4.3 ± 0.5) subjects were studied at baseline and after a 2-wk dietary intervention. Muscle biopsies were obtained from the subjects in the resting (basal) state and immediately following a 30-min exercise bout (70% Vo(2 max)). Muscle lysates were analyzed for AMPK activity and Akt phosphorylation and for TBC1D1 and AS160 phosphorylation on known or putative AMPK and Akt sites as follows: AS160 Ser(711) (AMPK), TBC1D1 Ser(231) (AMPK), TBC1D1 Ser(660) (AMPK), TBC1D1 Ser(700) (AMPK), and TBC1D1 Thr(590) (Akt). The diet intervention that consisted of a major shift in the macronutrient composition resulted in a 4.2 ± 0.4 kg weight loss (P < 0.001) and a significant increase in insulin sensitivity (M value 5.6 ± 0.6), but surprisingly, there was no effect on expression or phosphorylation of any of the muscle-signaling proteins. Exercise increased muscle AMPKα2 activity but did not increase Akt phosphorylation. Exercise increased phosphorylation on AS160 Ser(711), TBC1D1 Ser(231), and TBC1D1 Ser(660) but had no effect on TBC1D1 Ser(700). Exercise did not increase TBC1D1 Thr(590) phosphorylation or TBC1D1/AS160 PAS phosphorylation, consistent with the lack of Akt activation. These data demonstrate that a single bout of exercise regulates TBC1D1 and AS160 phosphorylation on multiple sites in human skeletal muscle. 相似文献
128.
A Genome-wide Map of CTCF Multivalency Redefines the CTCF Code 总被引:1,自引:0,他引:1
Hirotaka Nakahashi Kyong-Rim Kieffer Kwon Wolfgang Resch Laura Vian Marei Dose Diana Stavreva Ofir Hakim Nathanael Pruett Steevenson Nelson Arito Yamane Jason Qian Wendy Dubois Scott Welsh Robert D. Phair B. Franklin Pugh Victor Lobanenkov Gordon L. Hager Rafael Casellas 《Cell reports》2013,3(5):1678-1689
- Download : Download full-size image
129.
Arito Yamane Davide F. Robbiani Wolfgang Resch Anne Bothmer Hirotaka Nakahashi Thiago Oliveira Philipp C. Rommel Eric J. Brown Andre Nussenzweig Michel C. Nussenzweig Rafael Casellas 《Cell reports》2013,3(1):138-147
- Download : Download full-size image
130.