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   715篇
  免费   34篇
  2023年   5篇
  2022年   5篇
  2021年   5篇
  2020年   6篇
  2019年   8篇
  2018年   9篇
  2017年   11篇
  2016年   11篇
  2015年   17篇
  2014年   29篇
  2013年   40篇
  2012年   54篇
  2011年   50篇
  2010年   32篇
  2009年   36篇
  2008年   42篇
  2007年   46篇
  2006年   34篇
  2005年   39篇
  2004年   40篇
  2003年   40篇
  2002年   41篇
  2001年   11篇
  2000年   7篇
  1999年   14篇
  1998年   7篇
  1997年   10篇
  1996年   6篇
  1995年   7篇
  1994年   9篇
  1993年   8篇
  1992年   6篇
  1991年   5篇
  1990年   5篇
  1989年   5篇
  1988年   3篇
  1987年   5篇
  1986年   4篇
  1985年   4篇
  1984年   6篇
  1983年   4篇
  1981年   2篇
  1980年   4篇
  1979年   4篇
  1977年   1篇
  1976年   1篇
  1975年   2篇
  1974年   4篇
  1973年   2篇
  1972年   1篇
排序方式: 共有749条查询结果,搜索用时 15 毫秒
51.
A 36-kDa allergen, Tri a Bd 36K, was purified from wheat albumin and characterized. The protein was similar to barley peroxidase BP-1 both in its amino acid sequence and peroxidase activity. The enzyme seemed to contain L-fucose and D-mannose and the glycan moiety reacted with IgE antibodies in a patient's serum.  相似文献   
52.
Growth hormone (GH), prolactin (PRL) and somatolactin (SL) are members of a pituitary hormone family that are believed to have evolved from a common ancestral gene by duplication and subsequent divergence. Since these hormones are found both in bony fish and cartilaginous fish, their ancestral form(s) should be present in the Agnatha. Thus, although there is no convincing evidence that the lamprey pituitary secretes GH or PRL, GH- and/or PRL-like immunoreactivity was examined in the pituitary of adult sea lampreys (Petromyzon marinus), using antibodies to GHs, PRLs and SL of mammalian and/or fish origins. Our initial attempt with ordinary immunohistochemical procedures failed to detect any positive reactions in the lamprey pituitary. Following the hydrated autoclave pretreatment of the sections, anti-salmon GH, anti-salmon PRL and anti-blue shark GH gave positive reactions in most cells distributed in the dorsal half of the proximal pars distalis. These results suggest that the material immunoreactive to those antibodies is related, to some extent, to GH/PRL, but enhancement of immunoreactivity to reveal this by the hydrated autoclave pretreatment of sections is needed due to low crossreactivity. The similarity of the topographic distributions within the pituitary between lampreys and teleosts suggests that lamprey GH/PRL-like cells are GH cells of the lamprey.  相似文献   
53.
54.
Synaptic mechanisms underlying pheromonal memory in vomeronasal system   总被引:2,自引:0,他引:2  
When female mice are mated, they form a memory of the pheromonal signal of the male with which they mated. Our research objective was to determine the neural mechanisms underlying learning and memory by employing a convenient model of pheromone-induced olfactory memory (pheromonal memory). Formation of pheromonal memory depends on the association between mating and exposure to pheromones. Synaptic plasticity involving this memory occurs in the accessory olfactory bulb (AOB), depending on vaginocervical stimulation at mating. The vaginocervical stimulation at mating reduces the dendrodendritic feedback inhibition of principal neurons (mitral/tufted (MT) cells) in the AOB and enhances their cell activity. The enhancement of activity induces on these plastic changes in dendrodendritic synapses, which in turn enhance GABA-mediated inhibition of MT cell activity. This "self-inhibition" of MT cells activity in response to pheromonal signals of the partner can disrupt its signals at the AOB thereby preventing the signals from reaching the central brain. The formation and maintenance of pheromonal memory is based on this inhibition mechanism.  相似文献   
55.
Neonatally streptozotocin-induced diabetic (n-STZ) rats were given food containing Lactobacillus GG cells (GG) or a control diet (control), from 9 to 18 weeks of age. The GG cells significantly lowered the blood hemoglobin A(1C) (HbA(1C)) level and improved glucose tolerance in n-STZ rats (p<0.05). In the GG group, the serum insulin level at 30 min after glucose loading was significantly higher than in the control group (p<0.05).  相似文献   
56.
57.
We have previously identified 17 biomarker genes which were upregulated by whole virion influenza vaccines, and reported that gene expression profiles of these biomarker genes had a good correlation with conventional animal safety tests checking body weight and leukocyte counts. In this study, we have shown that conventional animal tests showed varied and no dose-dependent results in serially diluted bulk materials of influenza HA vaccines. In contrast, dose dependency was clearly shown in the expression profiles of biomarker genes, demonstrating higher sensitivity of gene expression analysis than the current animal safety tests of influenza vaccines. The introduction of branched DNA based-concurrent expression analysis could simplify the complexity of multiple gene expression approach, and could shorten the test period from 7 days to 3 days. Furthermore, upregulation of 10 genes, Zbp1, Mx2, Irf7, Lgals9, Ifi47, Tapbp, Timp1, Trafd1, Psmb9, and Tap2, was seen upon virosomal-adjuvanted vaccine treatment, indicating that these biomarkers could be useful for the safety control of virosomal-adjuvanted vaccines. In summary, profiling biomarker gene expression could be a useful, rapid, and highly sensitive method of animal safety testing compared with conventional methods, and could be used to evaluate the safety of various types of influenza vaccines, including adjuvanted vaccine.  相似文献   
58.
The function of GABA in the adrenal medulla is still controversial. We will review experimental results in vivo and in vitro in adrenal chromaffin cells of various mammals to clarify what has been elucidated and what still remains to be settled.  相似文献   
59.
60.
Triploid Fritillaria camschatcensis (L.) Ker-Gawler (2n = 3x = 36) is a wild species growing in the low-lying areas of Hokkaido Island, Japan, including the Sapporo campus of Hokkaido University. Many F. camschatcensis plants grew on the campus about a century ago, but we seldom find the plants nowadays and so a project to restore this species is being planned. Because preservation of genetic diversity and composition in populations has become a major target of conservation, this study compared variation in the F. camschatcensis population on the Sapporo campus with that in two other populations in Hokkaido. Phenetic variation assessed by 57 randomly amplified polymorphic DNA markers showed that the three populations were significantly distinct from each other; analysis of molecular variance showed 64.3% of variation (P < 0.001) existed among the three populations. Comparison of phenetic diversity on the Sapporo campus population with that in the two other populations showed that the Sapporo campus population contained large genetic variation despite reduced plant numbers. These results indicate that multiplying F. camschatcensis individuals on the Sapporo campus is adequate to restore the Sapporo campus population because this population contains enough genetic diversity, and that transplanting from other populations should be avoided so as not to introduce different genotypes into the campus. These results will be used to design the restoration strategy.  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