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   1935篇
  免费   114篇
  国内免费   1篇
  2021年   15篇
  2020年   16篇
  2019年   23篇
  2018年   14篇
  2017年   26篇
  2016年   41篇
  2015年   70篇
  2014年   78篇
  2013年   115篇
  2012年   133篇
  2011年   131篇
  2010年   72篇
  2009年   88篇
  2008年   121篇
  2007年   134篇
  2006年   110篇
  2005年   112篇
  2004年   107篇
  2003年   140篇
  2002年   116篇
  2001年   15篇
  2000年   16篇
  1999年   19篇
  1998年   26篇
  1997年   16篇
  1996年   15篇
  1995年   20篇
  1994年   15篇
  1993年   15篇
  1992年   13篇
  1991年   9篇
  1990年   10篇
  1989年   8篇
  1988年   6篇
  1987年   12篇
  1986年   10篇
  1984年   10篇
  1983年   7篇
  1982年   7篇
  1981年   6篇
  1980年   8篇
  1979年   10篇
  1978年   15篇
  1977年   9篇
  1976年   8篇
  1975年   8篇
  1974年   8篇
  1973年   10篇
  1972年   7篇
  1971年   10篇
排序方式: 共有2050条查询结果,搜索用时 15 毫秒
1.
2.
3.
The substrate level of the photosynthetic reductive pentosephosphate cycle in spinach leaves during SO2 fumigation wassurveyed. At the beginning of SO2 fumigation, fructose-1,6-bisphosphateincreased and fructose-6-phosphate decreased, while ribulose-1,5-bisphosphateremained unchanged and 3-phosphoglyceric acid rapidly decreased.These results suggested that the inhibition of photosynthesisin spinach leaves with SO2 might be due to inactivation of fructose-1,6-bisphosphatase. (Received May 26, 1982; Accepted September 27, 1982)  相似文献   
4.
5.
6.
Summary A new haptenic compound, a muramyl dipeptide (MDP) derivative (designated as L4-MDP-ONB) cross-reactive with Bacillus Calmette Guerin (BCG) was synthesized. The cross-reactivity of L4-MDP hapten to BCG was demonstrated from the following evidence; (a) lymph node cells from BCG-primed C3H/HeN mice exhibited appreciable L4-MDP-specific proliferative responses to the in vitro stimulation of L4-MDP-modified syngeneic cells (L4-MDP-self); (b) inoculation of L4-MDP-self into footpads of BCG-primed C3H/HeN mice elicited ample delayed type-hypersensitivity (DTH) responses in vivo as measured by footpad swelling; and (c) BCG-primed mice contained L4-MDP-reactive helper T cell activity which functions to augment the generation of effector T cell responses to cell surface antigens. This crossreactivity between L4-MDP hapten and BCG as measured by the helper T cell activity was applied to enhanced induction of tumor-specific immunity. When BCG-primed C3H/HeN mice were immunized with L4-MDP-modified syngeneic X5563 tumor cells, these mice could generate augmented tumor-specific in vivo protective (tumor neutralizing) immunity as well as in vitro cytotoxic T cell responses. These results indicate the effectiveness of L4-MDP hapten in augmenting tumor-specific immunity. The present approach is discussed in the context of potential advantages of this new hapten for its future application to clinical tumor systems.  相似文献   
7.
1. 1. The study aimed at knowing whether thermal sensation during afternoon cool exposure could be influenced by bright light (4000 lx) or dim light (200 lx) in the forenoon.
2. 2. The subjects felt cooler after exposure to dim light than to bright light.
3. 3. Melatonin in the urine was significantly higher in bright light than in dim light at 10:30 h and at noon.
  相似文献   
8.
9.
The primary purpose of this study was to test our hypothesis that the behavior of self-selecting the preferred ambient illuminance might be determined by a load error between the core temperature and its set-point. Seven female volunteers were asked to choose the preferred ambient light intensity by adjusting a rheostat from the time when they rose spontaneously in the morning to the time when they felt sleepy and retired. Rectal temperature was measured every 10 min. Their preferred ambient light intensity increased quickly and then gradually after they rose and rose to approximately 2000 lx over 3 hrs. It decreased gradually and then quickly to the time when they retired. We discussed these findings in terms of a load error between the actual core temperature and its set-point.  相似文献   
10.
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