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   302篇
  免费   17篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2018年   4篇
  2017年   7篇
  2016年   13篇
  2015年   9篇
  2014年   16篇
  2013年   19篇
  2012年   12篇
  2011年   14篇
  2010年   12篇
  2009年   7篇
  2008年   13篇
  2007年   10篇
  2006年   15篇
  2005年   18篇
  2004年   10篇
  2003年   9篇
  2002年   11篇
  2001年   8篇
  2000年   10篇
  1999年   8篇
  1998年   3篇
  1997年   2篇
  1996年   9篇
  1995年   1篇
  1994年   2篇
  1993年   11篇
  1992年   6篇
  1991年   4篇
  1990年   5篇
  1989年   2篇
  1988年   10篇
  1987年   5篇
  1986年   7篇
  1985年   4篇
  1984年   3篇
  1983年   4篇
  1982年   1篇
  1979年   6篇
  1978年   2篇
  1976年   1篇
  1975年   1篇
  1972年   1篇
排序方式: 共有319条查询结果,搜索用时 31 毫秒
61.
Amyloid β fibrillation is an early event in Alzheimer’s disease, so its detection is important to understand its roles in Alzheimer’s disease. Curcumin, which has poor water solubility, has been reported to have many pharmacological activities including potent anti-amyloid β fibril activity in Alzheimer’s disease. In this study, we found that curcumin analogues with the fluorescence property instead of non-inhibition of amyloid β fibrils. The development of new curcumin analogue, Me-CUR (9), as fluorescent switchable probe to detect amyloid β fibrils is described. Me-CUR (9) shows excellent fluorescence, especially higher than ThT (4), in the presence of amyloid β fibrils. These results suggest that Me-CUR (9) can become a useful in vitro amyloid fluorescence sensor for diagnosis of Alzheimer’s disease.  相似文献   
62.
This study aimed to clarify the distribution of the ear side of mobile phone use in the general population of Japan and clarify what factors are associated with the ear side of mobile phone use. Children at elementary and junior high schools (n = 2,518) and adults aged ≥20 years (n = 1,529) completed an Internet‐based survey. Data were subjected to a logistic regression analysis. In children, due to the tendency to use the dominant hand, we analyzed the factors associated with the use of right ear in right‐handed people. Statistically significant differences were observed only in talk time per call (odds ratio (OR) = 2.17; 95% confidence interval (CI): 1.22–3.99). In adults, due to the tendency to use the left ear, we analyzed factors associated with the use of left ear in right‐handed people. Significant differences were observed in those aged 30–39 years (OR = 2.55; 95% CI: 1.79–3.68), those aged 40–49 years (OR = 3.08; 95% CI: 2.15–4.43), those aged >50 years (OR = 1.85; 95% CI: 1.20–2.85), and in those with a percentage of total talk time when using mobile phones at work of 51–100% (OR = 1.75; 95% CI: 1.21–2.55). We believe that future epidemiological studies on mobile phone use can be improved by considering the trends in mobile phone use identified in this study. Bioelectromagnetics. 39:53–59, 2018. © 2017 Wiley Periodicals, Inc.  相似文献   
63.
Sillaginid juveniles collected from the surf zone at Tigbauan, Iloilo, Philippines, between May 1986 and September 1987 were identified asSillago aeolus (n=702, 8.9–26.0 mm SL) andS. sihama (n=3414, 8.6–22.9 mm SL), based on the numbers of dorsal and anal soft fin rays and vertebrae. The two species were easily distinguishable by the pattern of melanophores distributed on the caudal fin base,S. aeolus having a triangular-shaped cluster, whereas the melanophores formed a vertical line inS. sihama. The ratios of pre-anal and caudal peduncle lengths to SL also differed between the species, both being higher inS. aeolus. The occurrence ofS. aeolus was limited to the dry season, from January to March. On the other hand,S. sihama occurred year-round, although a peak was observed in the dry season, from November to April.  相似文献   
64.
65.
BackgroundAbnormal cardiac uptake of 123I-metaiodobenzylguanidine (123I-MIBG) is a diagnostic marker of Lewy body diseases (LBDs), e.g., Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). Planar imaging is generally used to assess cardiac sympathetic dysfunction in 123I-MIBG scintigraphy; however, its clinical utility requires further improvement. We hypothesized that the co-registration of single-photon emission tomography (SPECT) and computed tomography (CT) images would improve the diagnostic accuracy of 123I-MIBG cardiac scintigraphy for LBDs. This study sought to evaluate the effects of SPECT/CT imaging on 123I-MIBG cardiac scintigraphy for diagnosing LBDs.MethodsWe retrospectively investigated data of 54 patients (consecutive 18 patients in each PD, DLB, and idiopathic normal pressure hydrocephalus [iNPH] groups) who underwent 123I-MIBG cardiac scintigraphy (planar and SPECT/CT) because of suspected LBDs at the Tohoku University hospital from June 2012 to June 2015. We compared the diagnostic accuracies of the conventional planar 123I-MIBG method and SPECT/CT methods (manual and semi-automatic).ResultsIn the conventional planar analysis, 123I-MIBG uptake decreased only in the DLB group compared with the iNPH group. In contrast, the SPECT/CT analysis revealed significantly lower 123I-MIBG uptake in both the PD and DLB groups compared with the iNPH group. Furthermore, a receiver operating characteristic analysis revealed that both the manual and semi-automatic SPECT/CT methods were superior to the conventional planar method in differentiating the 3 disorders.ConclusionsSPECT/CT 123I-MIBG cardiac scintigraphy can detect mild cardiac sympathetic dysfunction in LDBs. Our results suggest that the SPECT/CT technique improves diagnostic accuracy for LBDs.  相似文献   
66.
Neutrophils biosynthesize leukotoxin, 9, 10-epoxy-12-octadecenoate   总被引:1,自引:0,他引:1  
An epoxy derivative of linoleate, 9,10-epoxy-12-octadecenoate, was demonstrated to be biosynthesized by neutrophils from various sources such as canine and human blood, and guinea-pig peritonea. It was nominated as leukotoxin from its 'toxic' activity onto mitochondrial respiration. From the reaction mixture of leukocytes with linoleate, an isomer of leukotoxin, 12,13-epoxy-9-octadecenoate, and a 'non-toxic' hydroxy derivative of linoleate, 9-hydroxy-12-octadecenoate, were detected. Such a cascade reaction of linoleate by leukocytes was discussed. Biosynthesis of leukotoxin by neutrophils was substantially enhanced by the presence of calcium ion and calcium-ionophore, A23187. Neutrophils contained leukotoxin, ca. 7 f moles/cell, which was extractable by 60% ethanol, but little of the isomer.  相似文献   
67.
In human peripheral polymorphonuclear leukocyte (PMN), 10% of PLA2 activity was found in the particulate fraction. In the particulate fraction, the activity of phospholipase A2 was enhanced 270% by 100 microM guanosine 5'-[gamma-thio]triphosphate, a hydrolysis-resistant analog of GTP. In the soluble fraction, such enhancement was not observed. Guanosine 5'-[beta-thio]diphosphate (2 mM), which irreversibly inactivates GTP-binding protein, blocked the enhancement in the particulate fraction. Membrane-binding phospholipase A2 activity of PMN would thus appear to be regulated directly by GTP-binding protein.  相似文献   
68.
Development of swimming and feeding abilities based on morphological development of larval and early juvenileChanos chanos was investigated. In larvae smaller than about 6.5 mm SL, mechanical supports of fins and branchial arches were in a primordial stage of development. Supports and rays of the vertical fins and branchial arches rapidly developed from 6.5 mm SL, and all components appeared by about 10.5 mm SL. Thereafter body depth proportion changed and the supports and rays of the paired fins and gill-rakers developed. These developmental events were nearly or totally completed by about 17 mm SL, and we concluded that the larvae transformed to juveniles at this size. By this time, the mode of swimming of the fish shifted from undulating locomotion to caudal propulsion and that of feeding from swallowing paniculate food to filtering and concentrating substrate food matters using gill-rakers and the epibranchial organ. One of the most characteristic, and well-known, phenomena in the life history ofChanos chanos is the mass occurrence in the surf zone of postlarvae of a limited size range. In view of the scheme of the development of mechanical supports of the body and fins, they may acquire a swimming ability strong enough to move against the current only upon reaching about 10.5 mm SL, and if active shoreward migration of the larvae occurs, it is only during the late period of their journey from the spawning grounds to the shore. The sudden disappearance from the surf zone of larvae larger than 15–16 mm SL is obviously related to a change in food habit.  相似文献   
69.
70.
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