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   206篇
  免费   20篇
  2023年   1篇
  2022年   1篇
  2021年   4篇
  2020年   1篇
  2019年   1篇
  2018年   3篇
  2017年   2篇
  2016年   5篇
  2015年   13篇
  2014年   10篇
  2013年   18篇
  2012年   16篇
  2011年   5篇
  2010年   12篇
  2009年   13篇
  2008年   16篇
  2007年   12篇
  2006年   16篇
  2005年   14篇
  2004年   17篇
  2003年   9篇
  2002年   17篇
  2001年   3篇
  1999年   1篇
  1998年   4篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1993年   2篇
  1991年   1篇
  1975年   1篇
  1974年   1篇
  1972年   2篇
排序方式: 共有226条查询结果,搜索用时 78 毫秒
21.
22.
Genetic variants of NLRP3 and NLRP1 are known to modulate levels of pro-inflammatory cytokine interleukin (IL)-1β. The purpose of this study was to investigate the association of NLRP3/NLRP1 polymorphisms with susceptibility and clinical features of malignant melanoma in a Swedish case-control study. Common variants in NLRP3/NLRP1 were investigated in sporadic malignant melanoma patients and healthy controls followed by analysis using logistic regression. NLRP3 variant (rs35829419) was significantly more common in male patients than in controls (OR, 2.22; CI, 1.27-3.86). Upon stratification, significant association with nodular melanoma was observed (OR, 2.89; CI, 1.33-6.30), which intensified in male patients (OR 4.03, CI 1.40-11.59). The NLRP1 variant (rs12150220) was significantly more common in fair-skinned female patients (OR, 1.85; CI, 1.04-3.33) and showed strong associations with nodular melanoma (OR, 6.03; CI, 1.33-25). Our data suggest that NLRP3/NLRP1 polymorphisms are associated with melanoma susceptibility; these findings warrant validation in other independent populations.  相似文献   
23.
24.
B‐cell differentiation is one of the most recognized examples of the progressive lineage commitment that is distinctive for stem cell systems. However, the characteristics of the stage just before a cell becomes restricted to the B‐cell lineage are less understood. Using single‐cell RNA sequencing technology, Rolink and colleagues are able to define the cellular heterogeneity at this step and challenge our understanding of developmental trajectories in early B‐lymphoid development (Alberti‐Servera et al, 2017 ).  相似文献   
25.
26.
-Tocopherol and ascorbic acid have been suggested to play a role in breast cancer prevention due to their antioxidative capacity. Increased exposure to endogenous and exogenous sex steroids is a known risk factor for breast cancer. We have studied the effects of -tocopherol and ascorbic acid on hydrogen peroxide induced cell death in sex hormone treated normal breast epithelial cells in culture. We found that -tocopherol but not ascorbic acid alone protected the cells. The effect of -tocopherol increased when ascorbic acid was added to the cultures. The hydrogen peroxide degradation rate decreased in cultures treated with -tocopherol alone and in combination with ascorbic acid compared to cells grown in medium or with ascorbic acid only. Oestradiol and progesterone treatment did not influence the results. Possible beneficial effects of combining various antioxidants, endogenous as well as exogenous, on human breast tissue need to be investigated further both in vivo and in vitro.  相似文献   
27.
28.
Many damselfishes exclude other grazers from their territories and “farm” filamentous algae within their territories. In this study the indirect effect of damselfish territories on faunal composition and abundance of internal bioeroders of dead Acropora formosa (Dana, 1846) was investigated in territories of two damselfish species, Stegastes nigricans (Lacepède, 1802) and Plectroglyphidodon lacrymatus (Quoy and Gaimard, 1825). S. nigricans tends to be more protective and defend their territories more aggressively than P. lacrymatus. Newly killed branches of A. formosa were placed inside and outside damselfish territories, for 1 or 2 years, at a coral reef near Zanzibar, Tanzania. As predicted, the coral branches became covered with more filamentous algae in the S. nigricans territories than in the controls, with intermediate levels in the P. lacrymatus territories. Among the internal bioeroding fauna, polychaetes were by far the most common group. In total, there were significantly more borers in the first year than the second, which was mainly due to a high abundance of sabellids. Furthermore, sabellids were significantly more abundant in control areas and in the P. lacrymatus territories compared to the S. nigricans territories. However, many other genera showed the opposite pattern, with more polychaetes in the fish territories compared to the controls. There was also a clear difference in assemblage structure between S. nigricans territories and controls. Thus, we found strong effects of whether a piece of coral was placed inside or outside a damselfish territory on the abundance of many of the bioeroding taxa. We discuss multiple reasons for these indirect effects of the territories, including that deposit feeding bioeroders may benefit from the dense algal turf found inside the territories whereas suspension feeding bioeroders may benefit from substrate with less filamentous algae found outside territories. Considering our results in the context of the large areas of coral reefs that typically are defended as territories by damselfishes, these fish are likely to have a considerable impact on the boring community of a coral reef.  相似文献   
29.
The tendency in the paper industry is to close all water loops to save water. This leads to higher process temperatures and may increase the colloidal and dissolved material in the process circulation. Increase of nutrients in the water circuits may favor microbiological growth and fouling. In this paper the chemical and microbial compositions of water circuits and deposits were studied of two closed cycled paper/board mills, one mill totally closed (0 m(3) waste water t(-1)), and the other low discharging (about 4 m(3 )t(-1)). The zero discharge mill accumulated high amounts (>10 g C L(-1)) of organic carbon in the circulation waters, about 40% of which composed of volatile acids (lactic, acetic, propionic and butyric acid). Water contents of sulfate, chloride, sodium and calcium increased to >1 g L(-1) of each. q-PCR targeted on 16S rRNA genes indicated that the bacteria in water circuits were mainly viable cells. In both mills anaerobic growth (10(6)-10(8) CFU mL(-1)) equalled or exceeded aerobic growth, with odor problem but no actual slime problem. The major part (40%) of all identifiable bacterial sequences were closest but yet distant (<96%) to Enterococcus cecorum and in the 4 m(3 )t(-1) discharging mill also Bacillus thermoamylovorans and Bacillus coagulans. Slimes and deposits from the mills contained high amounts, >/=10(8) g(-1), of archaean, but only the genus Methanothrix was identifiable from the cloned sequences. The findings indicate that closing the water circuits strongly limited diversity of the microbiota but allowed efficient mineralization of the dissolved and suspended matter.  相似文献   
30.
Chemiluminescence systems enhanced by either isoluminol or luminol in combination with a peroxidase are sensitive methods for the detection of reactive oxygen species (ROS) generated by phagocyte NADPH oxidase. The two amplifying substrates are structurally very similar, differing only in the position of the amino group in the aromatic ring of the molecules. This difference renders isoluminol a less lipophilic molecule that is less permeable to biological membranes. The use of isoluminol is consequently restricted to studies dealing with the secretion of oxygen metabolites. In this study we show that synthetic peptides derived from the N‐terminal domain of the calcium‐regulated protein annexin AI interfere with the detection of radicals in an isoluminol‐amplified, but not in a luminol‐amplified, system. The annexin AI‐derived peptides reduce the light output with isoluminol excited by superoxide and horseradish peroxidase (HRP) in formyl‐methionyl‐leucyl‐phenylalanine‐ and phorbol myristate acetate‐stimulated cells, as well as by hydrogen peroxide and HRP. The precise mechanism for the inhibition is not known. The results presented strongly suggest that a reduced cellular response detected with isoluminol‐amplified chemiluminescence should be confirmed with an alternative technique to determine release of superoxide anions and hydrogen peroxide. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
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