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   900篇
  免费   43篇
  国内免费   1篇
  2023年   2篇
  2022年   6篇
  2021年   12篇
  2020年   6篇
  2019年   7篇
  2018年   13篇
  2017年   15篇
  2016年   24篇
  2015年   24篇
  2014年   36篇
  2013年   61篇
  2012年   65篇
  2011年   87篇
  2010年   39篇
  2009年   43篇
  2008年   61篇
  2007年   63篇
  2006年   61篇
  2005年   65篇
  2004年   44篇
  2003年   52篇
  2002年   39篇
  2001年   7篇
  2000年   3篇
  1999年   6篇
  1998年   9篇
  1997年   13篇
  1996年   4篇
  1995年   5篇
  1994年   9篇
  1993年   2篇
  1992年   8篇
  1991年   4篇
  1990年   6篇
  1989年   2篇
  1988年   2篇
  1987年   3篇
  1986年   3篇
  1985年   2篇
  1984年   2篇
  1983年   4篇
  1982年   9篇
  1981年   3篇
  1980年   4篇
  1979年   2篇
  1978年   1篇
  1977年   3篇
  1972年   1篇
  1958年   1篇
  1956年   1篇
排序方式: 共有944条查询结果,搜索用时 31 毫秒
941.
During the period fromlate May through December 1981, tree-dwelling beetles were regularly surveyed at three deciduous oak and two evergreen forests in the vicinity of Gifu City. Chrysomelidae and Curculionidae were abundant in these forests. The species diversity and the seasonal succession of species were most apparent in May and June. The three deciduous oak forests, with many species and high equitability, showed more diverse community structure, but fewer individuals, when compared with the two evergreen forests. Furthermore, the species compositions of the deciduous oak forests were seasonally and spatially more heterogeneous than those of the evergreen forests. A few dominant species, however, had a strong influence on the community structure. The relationship between the diversity index and sample size was examined. The diversity index changed with the sample size, and the range of the variation diminished as the sample size increased. However, equilibrium was not reached even in the largest sample size used in this study (20 samples). There was a significantly high correlation (P<0.001) in diversity index between the smaller sample sizes (5, 10, 15) and the largest. It was, therefore, shown that community structures can be compared on the basis of the diversity indices from samples of constant size, even when the samples are small. Contribution No. 108 from Lab. Ent., Fac. Agr., Gifu Univ.  相似文献   
942.
To determine whether synovial mononuclear cells include a population of tumor necrosis factor α-produeing T cells, we measured tumor necrosis α levels in culture supernatants of synovial mononuclear cells by ELISA and analyzed tumor necrosis α mRNA-positive cell frequencies. There were no significant differences in the spontaneous levels of TNF α between synovial mononuclear cells and peripheral mononuclear cells. The frequency of tumor necrosis factor α mRNA-positive cells in synovial mononuclear cells was higher than that of peripheral mononuclear cells. When stimulated with a superantigen, mononuclear cells from the synovial fluid of rheumatoid arthritis patients showed higher levels of tumor necrosis factor α production (1,035 ± 817 pg/ml) than did mononuclear cells from their peripheral blood (236 ± 180 pg/ml). In addition, we observed that a few T cell clones were resistant to superantigenic restimulation in vitro. We conclude that when these types of T cells persist in the synovium, they play a role in the development of rheumatoid arthritis via a mechanism involving tumor necrosis factor α production.  相似文献   
943.
The communication architecture of the DIMMnet-1 network interface based on MEMOnet is described. MEMOnet is a class of a network interface plugged into a memory slot. This paper proposes three message transfer mechanisms named atomic on-the-fly sending (AOTF), block on-the-fly sending (BOTF) and OTF receiving with selective address translation. The DIMMnet-1 prototype will have an ASIC named Martini, two banks of PC133 based SO-DIMM slots and an 8 Gbps full duplex optical link. The software overhead incurred to generate a message is only 1 CPU cycle and the estimated hardware delay is 105 ns using AOTF. The estimated hardware delay for receiving to on chip memory using OTF receiver is 90 ns. The estimated achievable sending bandwidth of DIMMnet-1 using BOTF is 984 MB/s which was observed in our experiments. This bandwidth is 7.4 times higher than the maximum bandwidth of PCI. This high performance is available even when simultaneous sending and receiving are executed on a cheap personal computer with DIMM slots. This paper also discribes the effects of BOTF for a PCI-based NIC.  相似文献   
944.
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