全文获取类型
收费全文 | 325149篇 |
免费 | 29323篇 |
国内免费 | 282篇 |
出版年
2018年 | 3605篇 |
2017年 | 3450篇 |
2016年 | 4659篇 |
2015年 | 5161篇 |
2014年 | 6320篇 |
2013年 | 9025篇 |
2012年 | 9885篇 |
2011年 | 10559篇 |
2010年 | 7324篇 |
2009年 | 6482篇 |
2008年 | 9284篇 |
2007年 | 9482篇 |
2006年 | 8978篇 |
2005年 | 8524篇 |
2004年 | 8380篇 |
2003年 | 8170篇 |
2002年 | 7881篇 |
2001年 | 15476篇 |
2000年 | 15312篇 |
1999年 | 11750篇 |
1998年 | 3566篇 |
1997年 | 3666篇 |
1996年 | 3514篇 |
1995年 | 3226篇 |
1994年 | 3145篇 |
1993年 | 3044篇 |
1992年 | 9199篇 |
1991年 | 8975篇 |
1990年 | 9062篇 |
1989年 | 8642篇 |
1988年 | 8065篇 |
1987年 | 7647篇 |
1986年 | 6883篇 |
1985年 | 7193篇 |
1984年 | 5713篇 |
1983年 | 4968篇 |
1982年 | 3485篇 |
1981年 | 3258篇 |
1980年 | 3004篇 |
1979年 | 5380篇 |
1978年 | 4131篇 |
1977年 | 3776篇 |
1976年 | 3678篇 |
1975年 | 4274篇 |
1974年 | 4591篇 |
1973年 | 4716篇 |
1972年 | 4099篇 |
1971年 | 3764篇 |
1970年 | 3367篇 |
1969年 | 3149篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
75.
We studied the impulse activity of neurons of the basal and lateral amygdalar nuclei generated when experimental animals (rats) performed fast stereotyped food-procuring movements by the forelimb. Within the basolateral amygdala, there are neurons whose activity is related to different stages of getting off the food, and according to the characteristics of their spiking these neurons should be divided into a number of subpopulations. Activation forestalling the movement initiation by 0.5-1.0 sec was observed in most neurons of the basolateral amygdala; this is considered a manifestation of excitation related to a motivation component of the food-procuring behavior. Activation of amygdalar neurons following movement initiation can result from generation in this structure of additional excitation necessary for successful performance of a complete food-procuring motor cycle. 相似文献
76.
A rational attempt to prepare FmocHis(piTrt)OH regiospecifically gave in fact the well-known tau-trityl isomer, and experiments with model systems indicate that the prospects for access to pi-trityl histidine derivatives, which would be of great value for the racemization-free synthesis of histidine-containing peptides, are poor. 相似文献
77.
78.
N. P. Todaria 《Biologia Plantarum》1986,28(4):280-287
A comparative study of dark respiration and effects of high and low temperature on dark respiration in five greenhouse cultivated tropical and sub-tropical species was made. The respiration rates determined manometrically were low in all species. Respiration rates increased with increasing temperature. Low temperature treatment accelerated the rate of respiration at 25 °G except in two species. An attempt has been made to determine the critical and optimum temperature for these species. The respiratory behaviour of these species has been discussed with respect to their original habitats and prevailing environmental conditions. 相似文献
79.
80.