全文获取类型
收费全文 | 16094篇 |
免费 | 621篇 |
国内免费 | 4篇 |
出版年
2019年 | 213篇 |
2018年 | 258篇 |
2017年 | 219篇 |
2016年 | 257篇 |
2015年 | 169篇 |
2014年 | 261篇 |
2013年 | 1272篇 |
2012年 | 432篇 |
2011年 | 485篇 |
2010年 | 289篇 |
2009年 | 312篇 |
2008年 | 414篇 |
2007年 | 441篇 |
2006年 | 421篇 |
2005年 | 343篇 |
2004年 | 372篇 |
2003年 | 334篇 |
2002年 | 329篇 |
2001年 | 451篇 |
2000年 | 510篇 |
1999年 | 342篇 |
1998年 | 205篇 |
1997年 | 154篇 |
1996年 | 166篇 |
1995年 | 164篇 |
1992年 | 276篇 |
1991年 | 285篇 |
1990年 | 296篇 |
1989年 | 277篇 |
1988年 | 267篇 |
1987年 | 234篇 |
1986年 | 246篇 |
1985年 | 259篇 |
1984年 | 191篇 |
1983年 | 207篇 |
1982年 | 158篇 |
1980年 | 156篇 |
1979年 | 248篇 |
1978年 | 216篇 |
1977年 | 150篇 |
1975年 | 215篇 |
1974年 | 242篇 |
1973年 | 268篇 |
1972年 | 225篇 |
1971年 | 210篇 |
1970年 | 162篇 |
1969年 | 195篇 |
1968年 | 248篇 |
1967年 | 239篇 |
1966年 | 209篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
M C Rodriguez-Perez F de Vicente-Perez G Gomez-Jarabo Garcia 《Behavioral and neural biology》1992,58(3):165-170
The use of neurological tests in various states of undernutrition has confirmed the presence of delays in reflex ontogeny. Glucocorticoid administration in conditions of normal nutrition produces diminished growth and alterations in brain development similar to those observed in malnutrition, but there is not enough evidence about its effect on reflex development. In addition, some facts lead us to think that the use of permissive doses of these hormones during gestation could alleviate some of the effects of protein malnutrition on the development of pups. In the present study the ages at which certain reflexes appeared in the offspring of Wistar rats (Rattus norvegicus) fed a 20% (N) or 10% (M) protein diet from a week before conception to the end of lactation were observed. Each dietary group was subdivided into two: mothers receiving a daily injection during gestation either of a 0.9% NaCl (S) solution or of a 0.5 mg/100 g weight hydrocortisone acetate (C) solution. Results showed that the NS group of pups generally presented earlier ages of appearance of the variables under study than the remaining groups. Pups of the NC group presented delays in the age of appearance of reflexes. Finally, protein malnutrition delayed the appearance of reflexes and this effect seemed to be attenuated by treatment with hydrocortisone. Thus, hydrocortisone administration in protein malnutrition conditions seems to be beneficial although the results are harmful when administered under normal nutritional conditions. 相似文献
123.
Fifteen rats performed in a standard radial-arm maze task (Experiment 1) and in a modified task with a set of forced choices and a 15-min retention interval prior to completion of the maze (Experiment 2). In addition to the standard measure of choice in the radial-arm maze, orientation toward arms was measured and considered to constitute go-no-go "microchoice" decisions. Rats investigated but rejected many arms. A model of choice was developed in which it was assumed that choice decisions about arms were made independently and that microchoices were not selectively guided toward baited arms. The model performed nearly as well as the rats. These results place important limitations on the theory that choice behavior in the radial-arm maze is guided by a cognitive map. 相似文献
124.
Human analog tests of object permanence were administered to various breeds of adult dogs (Canis familiaris). Experiment 1 showed that the performance of terriers, sporting, and working dogs did not differ. Dogs succeeded in solving invisible displacement problems, but performance was lower than in visible displacement tests. Familiarity with the task had some influence because invisible displacement tests were more successful if they were preceded by visible displacement tests. In Experiment 2, odor cues from the target object and the hiding screens were available or were masked. Results confirmed that success was lower in invisible than in visible displacement tests and that these problems were solved on the basis of representation of visual information rather than on the basis of olfactory cues or of local rule learning. Dogs are compared with other species that display Stage 6 object permanence. 相似文献
125.
126.
Elders exposed to either progressive or imaginal relaxation procedures reported significant relaxation effects and showed improvement on measures of personal functioning. The results of the Physical Assessment Scale of the Relaxation Inventory indicated that relaxation responses were acquired within and across sessions. Large, consistent changes in relaxation occurred in all 4 sessions. The Symptom Checklist-90-R, which measures self-reported personal adjustment, showed significant positive changes following relaxation training and at 1-month follow-up. Elders who imagined muscle tension release profited as much as those engaged in actual muscle tension-release activities. This finding is of importance for older adults who may experience physical limitations that contraindicate muscle-tension-release procedures. 相似文献
127.
Adult age differences were explored on 3 short tests of the ability to generate and manipulate mental images. Age-related decrements were found in all 3 tests and were especially marked on the Clock Test. The tests are all reliable, as shown by test-retest reliability coefficients. Correlations also revealed that the Brooks Letter Test and the East-West Test appear to tap one common underlying ability, whereas the Clock Test measured a somewhat different ability. The East-West and Clock tests, in particular, may provide rapid and easily administered assessments of age-related changes in aspects of mental imagery. 相似文献
128.
The development of a campus-based Substance Abuse Prevention Program (SAPP) is discussed. The program has been designed in accordance with recommendations made by prominent authorities in this field, keeping in mind the needs of the campus at which the program is located. Suggestions for developing such programs are provided. 相似文献
129.
PHILLIP B. NIFFENEGGER THOMAS F. HOLCOMB 《Journal of counseling and development : JCD》1992,70(5):642-644
This article describes how state legislators were the target of a video marketing campaign aimed at increasing the funding for elementary counselors. How the video was developed, distributed, and used are discussed. 相似文献
130.