全文获取类型
收费全文 | 184279篇 |
免费 | 8174篇 |
国内免费 | 160篇 |
出版年
2020年 | 2864篇 |
2019年 | 3517篇 |
2018年 | 3649篇 |
2017年 | 4099篇 |
2016年 | 4747篇 |
2015年 | 3995篇 |
2014年 | 4893篇 |
2013年 | 23863篇 |
2012年 | 4948篇 |
2011年 | 4054篇 |
2010年 | 4058篇 |
2009年 | 4929篇 |
2008年 | 4280篇 |
2007年 | 3825篇 |
2006年 | 4337篇 |
2005年 | 4284篇 |
2004年 | 3812篇 |
2003年 | 3416篇 |
2002年 | 3214篇 |
2001年 | 3615篇 |
2000年 | 3461篇 |
1999年 | 3366篇 |
1998年 | 2899篇 |
1997年 | 2721篇 |
1996年 | 2627篇 |
1995年 | 2473篇 |
1994年 | 2446篇 |
1993年 | 2400篇 |
1992年 | 2842篇 |
1991年 | 2681篇 |
1990年 | 2547篇 |
1989年 | 2414篇 |
1988年 | 2390篇 |
1987年 | 2421篇 |
1986年 | 2398篇 |
1985年 | 2662篇 |
1984年 | 2692篇 |
1983年 | 2445篇 |
1982年 | 2438篇 |
1981年 | 2418篇 |
1980年 | 2231篇 |
1979年 | 2406篇 |
1978年 | 2260篇 |
1977年 | 2212篇 |
1976年 | 2052篇 |
1975年 | 2183篇 |
1974年 | 2278篇 |
1973年 | 2179篇 |
1972年 | 1748篇 |
1971年 | 1672篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
902.
Werner Lowenthal Ph.D. 《The Journal of medical humanities》1988,9(1):44-49
The purpose of this study was to document the responses of pharmacy students and pharmacists to various ethical dilemmas. The responses of the first professional year students, third professional year students and pharmacists were evaluated and compared. In most instances, responses indicated a high priority for patient/client welfare. Pharmacists and students reportedly act with regard to the dignity of life, individual freedom, and an inner sense of right. 相似文献
903.
904.
D. E. McMillan PhD. 《Integrative psychological & behavioral science》1988,23(2):57-66
Pigeons were trained to acquire a new four-response position sequence each day by pecking three response keys in a predetermined order. The key color varied after each correct response prior to food delivery. Acute administration of Γ9-tetrahydrocannabinol (Δ9-THC) up to a dose that completely eliminated responding, had no effect on total acquisition errors, or on within session patterns of error elimination. Chronic administration of Δ9-THC (3–10 mg/kg/day), either before or after the session for 4–7 weeks, also did not affect these error measures, although rates of responding were markedly suppressed and at times no responding occurred Discontinuation of Δ9-THC administration for periods of 4–6 weeks also was without effect on errors. These experiments suggest that neither acute nor chronic Δ9-THC produce specific effects on the repeated acquisition of serial position responses in pigeons. 相似文献
905.
John Polich Maung Aung Donald J. Dalessio 《Integrative psychological & behavioral science》1988,23(1):35-40
Experiment 1 elicited the P1, N1, P2, and N2 components of the long latency auditory evoked potential (AEP) using a 1000 Hz tone presented at 30, 50, or 70 dB SPL and 1-, 3-, or 5- second inter-stimulus intervals to assess the relative effects of the combination of these variables on component amplitude and latency. Four blocks of 16 tone presentations each were recorded from each subject to determine if changes in the AEP would occur because of short-term habituation. Both stimulus factors interacted significantly in a systematic fashion for the amplitude measures, with increases in latency also associated with increases in intensity and inter-stimulus interval. Only minor changes across the four trial blocks for either the amplitude or latency measures were observed over the various stimulus presentation conditions. Experiment 2 employed the same tone stimulus presented at 50 dB SPL and a 3-second inter-stimulus interval. Eight blocks of 64 trials were recorded from each subject on each day for four days to investigate long-term habituation effects. No substantial changes in any of the component amplitudes or latencies were obtained across the 32 trial blocks. It was concluded that intensity and inter-stimulus interval interact to determine AEP amplitude as well as latency values and that the constituent components do not change appreciably with repeated stimulus presentations, even after several days. 相似文献
906.
W. J. Jacobs M. Buttrick D. Kennedy 《Integrative psychological & behavioral science》1988,23(1):29-34
The present study outlines a rapid and sensitive on-the-baseline conditional emotional response (CER) procedure. Using rats as the experimental subject, the method detects delay conditioning, incubation, extinction and spontaneous recovery. In addition, the method detects conditional responding using electric shock ranging from 0.23 to 0.50 mA as the unconditional stimulus. Because of its speed and sensitivity, the method shelters the subject from unnecessary long-term deprivation and pain. 相似文献
907.
The manipulation of stimulus significance, by instructions from the experimenter, may be taken as an example of verbal conditioning. Consideration of such a mechanism suggested that personality effects previously found in conditioning studies should be apparent in instructional manipulations of significance in a study of the orienting response (OR) to words. Because of recent changes in dimensioning of the personality structure, some of the items originally used to define Eysenck’s extraversion (E) dimension are now used to assess the new dimension of psychoticism (P), suggesting that at least some of the established effects of E upon conditioning may be associated now with P. Hence the P scale was focused on in this study. Words differing on the evaluative dimension of the semantic differential were presented in three blocks, the first under indifferent instructions, the second under instructions to rate the words for their affective impact, and the third under indifferent instructions again. These blocks correspond to baseline, conditioning, and extinction conditions respectively. Electrodermal activity indicated enhanced conditioning, together with greater carry-over effects in the extinction phase, for low-P compared with high-P subjects. The results indicate the importance of personality effects in studies of stimulus significance and illustrate the value of the verbal conditioning mechanism in this area of the OR field. They also suggest the need to re-examine previously obtained E-effects in conditioning studies in light of changing personality tests. 相似文献
908.
909.
Thirty children and 5 adults participated in two experiments designed to compare visual processing in normal and reading disabled children. The children were aged 8, 10, and 12 years. In Experiment 1, subjects were asked to detect the temporal order of two briefly presented stimuli. In Experiment 2, subjects sorted cards containing bracket stimuli that did or did not produce perceptual grouping effects. Poor readers required more time to make accurate temporal order judgments and showed stronger perceptual grouping effects. For both good and poor readers, the amount of time necessary to make a correct temporal order judgment decreased, and perceptual grouping effects became weaker with age. However, the magnitude of the difference between the groups did not lessen with age. These results suggest that there are visual processing differences between good and poor readers that do not appear to correct by age 12. 相似文献
910.
Many studies directed at demonstrating perception without awareness have relied on the dissociation paradigm. Although the logic underlying this paradigm is relatively straightforward, definitive results have been elusive in the absence of any general consensus as to what constitutes an adequate measure of awareness. We propose an alternative approach that involves comparisons of the relative sensitivity of comparable direct and indirect indexes of perception. The only assumption required by the proposed approach is that the sensitivity of direct discriminations to relevant conscious information is greater than or equal to the sensitivity of comparable indirect discriminations. The proposed approach is illustrated through an evaluation of Avant and Thieman’s (1985) recent claim that an indirect measure of perception based on judgments of apparent visual duration provides a more sensitive indicator of perception than does a direct measure based on forced-choice recognition. Contrary to this claim, when direct and indirect indexes are measured under comparable conditions, an indirect measure based on judgments of perceived duration provides a less sensitive index of perceptual processing than do comparable direct measures. The proposed approach provides a general conceptual/methodological framework for using the dissociation paradigm in studies directed at establishing unconscious processes. 相似文献