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   720篇
  免费   110篇
  国内免费   37篇
  2024年   1篇
  2023年   26篇
  2022年   16篇
  2021年   26篇
  2020年   24篇
  2019年   53篇
  2018年   31篇
  2017年   30篇
  2016年   40篇
  2015年   24篇
  2014年   30篇
  2013年   131篇
  2012年   17篇
  2011年   22篇
  2010年   22篇
  2009年   37篇
  2008年   28篇
  2007年   30篇
  2006年   21篇
  2005年   30篇
  2004年   16篇
  2003年   23篇
  2002年   22篇
  2001年   18篇
  2000年   23篇
  1999年   11篇
  1998年   10篇
  1997年   9篇
  1996年   12篇
  1995年   12篇
  1994年   11篇
  1993年   7篇
  1992年   11篇
  1991年   8篇
  1990年   2篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1985年   5篇
  1984年   4篇
  1983年   3篇
  1982年   3篇
  1981年   2篇
  1980年   1篇
  1978年   1篇
  1977年   3篇
  1976年   2篇
  1975年   2篇
排序方式: 共有867条查询结果,搜索用时 15 毫秒
161.
Youth involvement in substance abuse can be a source of considerable distress for their parents. Unilateral family interventions have been advocated as one means by which concerned family members can be supported to assist substance‐abusing family members. To date there has been little research examining the impact of unilateral family interventions on the directly participating family members. In this study the early impact of an 8‐week parent‐group programme known as Behavioural Exchange Systems Training (BEST) was evaluated using a quasi‐experimental, waiting list control design. The professionally led programme had been developed to support and assist parents in their efforts to cope with adolescent substance abuse. Subjects were 66 parents (48 families) accepted for entry into the programme between 1997 and 1998. Comparison was made between 46 parents offered immediate entry into the programme and 20 parents whose entry to the programme was delayed by an 8‐week waiting list. At the first assessment 87% of parents showed elevated mental health symptoms on the General Health Questionnaire. Evidence suggested exposure to the intervention had a positive impact on parents. Compared to parents on the waiting list, parents entered immediately into the intervention demonstrated greater reductions in mental health symptoms, increased parental satisfaction, and increased use of assertive parenting behaviours. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
162.
The neurosteroid dehydroepiandrosterone (DHEA) is a powerful inhibitor of aggression in murine models when given for 15 days and potentially may be useful in the management of inappropriate human aggression. Although the biosynthesis and metabolism of DHEA have been described, little is known about the potential effect of the steroidal environment during sexual differentiation on the subsequent response to DHEA. Whether prenatal androgen exposure influences the subsequent response to DHEA was assessed by comparing the effect of DHEA (80 μg/d) on aggression in female offspring where dams were treated with 1, 10, or 100 μg of testosterone (T) on days 15 to 18 of gestation (Experiment I) or that developed in different uterine positions (Experiment II). The results showed that DHEA decreased attack behavior in general and that the 100‐μg prenatal T treatments enhanced the antiaggressive effect of this neurosteroid. Neither the lower doses of exogenously administered T nor the uterine position led to an enhanced response to DHEA. In addition, whether DHEA produced changes in social and nonsocial activities was examined. In the 100‐μg T females, DHEA increased the duration of the former and decreased the frequency and duration of the latter, indicating that it was not a general decrement in behavioral expression that mediated the enhanced response to the antiaggressive effect of DHEA. In the second experiment, DHEA treatment led to increased frequencies of social nonaggressive and nonsocial activities. However, the uterine positions × treatment interactions were not significant, demonstrating that contiguity to male fetuses did not differentially affect the response to DHEA. Aggr. Behav. 27:130–138, 2001. © 2001 Wiley‐Liss, Inc.  相似文献   
163.
In a residential research ward coffee drinking was studied in 9 volunteer human subjects with histories of heavy coffee drinking. A series of five experiments was undertaken to characterize adlibitum coffee consumption and to investigate the effects of manipulating coffee concentration, caffeine dose per cup, and caffeine preloads prior to coffee drinking. Manipulations were double-blind and scheduled in randomized sequences across days. When cups of coffee were freely available, coffee drinking tended to be rather regularly spaced during the day with intercup intervals becoming progressively longer throughout the day; experimental manipulations showed that this lengthening of intercup intervals was not due to accumulating caffeine levels. Number of cups of coffee consumed was an inverted U-shaped function of both coffee concentration and caffeine dose per cup; however, coffee-concentration and dose-per-cup manipulations did not produce similar effects on other measures of coffee drinking (intercup interval, time to drink a cup, within-day distribution of cups). Caffeine preload produced dose-related decreases in number of cups consumed. As a whole, these experiments provide some limited evidence for both the suppressive and the reinforcing effects of caffeine on coffee consumption. Examination of total daily coffee and caffeine intake across experiments, however, provides no evidence for precise regulation (i.e., titration) of coffee or caffeine intake.  相似文献   
164.
A caffeine versus placebo discrimination procedure was used to determine the lowest caffeine dose that could produce discrimination and self-reported mood effects in normal volunteers. During daily sessions under double-blind conditions, caffeine-abstinent subjects orally ingested a capsule containing 178 mg caffeine or placebo. Before beginning discrimination training, the compounds were identified to subjects by letter codes. Fifteen, 30, and 45 min after capsule ingestion, subjects guessed the capsule's letter code. Correct guesses at 45 min earned money. After each session, subjects received a supplementary capsule containing caffeine or placebo to ensure that, within each phase of the study, subjects received the same daily dose of caffeine equal to the training dose. Five of the 15 subjects acquired the caffeine versus placebo discrimination within the first 20 sessions (greater than or equal to 75% correct); 6 other subjects acquired the discrimination with additional training. Nine subjects who acquired the discrimination were subsequently trained at progressively lower caffeine doses. In general, the lowest dose to produce discrimination (greater than or equal to 75% correct) was also the lowest dose to produce self-reported mood effects: 4 subjects showed discrimination and self-reported mood effects at 100 mg caffeine, 2 at 56 mg, 1 at 32 mg, and 1 at 18 mg. One of these subjects also showed self-reported mood effects at 10 mg. The present study documents discriminative stimulus and self-reported mood effects of caffeine at doses below those previously shown to affect any behavior in normal volunteers.  相似文献   
165.
The acute effects of cocaine hydrochloride (4 to 96 mg/70 kg) and alcohol (0 to 1.0 g/kg), administered alone and in combination, were assessed in two experiments with human volunteers responding under a multiple schedule of repeated acquisition and performance of response chains. Subjects were intermittent users of cocaine and regular drinkers who were not cocaine or alcohol dependent. Alcohol was mixed with orange juice and ingested in six drinks within 30 min; cocaine was administered intranasally 45 min after completion of drinking. In each component of the multiple schedule, subjects completed response sequences using three keys of a numeric keypad. In the acquisition component, a new sequence was learned each session. In the performance component, the response sequence always remained the same. Results were consistent in both experiments, despite variations in the order in which the drugs were tested alone and in combination. Alcohol administered alone increased overall percentage of errors and decreased rates of responding in the acquisition component, whereas responding in the performance component generally was unaffected. Cocaine administered alone decreased rates of responding but did not affect accuracy of responding in the acquisition component, and enhanced accuracy of responding without affecting rates of responding in the performance component. The combined doses of cocaine and alcohol attenuated the effects observed with alcohol and cocaine alone. These results suggest that, under the conditions investigated in this study, (a) alcohol produces greater behavioral disruption than cocaine or cocaine-alcohol combinations, (b) cocaine and alcohol each attenuate effects of the other, and (c) such attenuation is most pronounced for cocaine attenuating the disruptive effects of alcohol.  相似文献   
166.
167.
Maternal serum screening for fetal Down syndrome has been integrated into routine antenatal care in most clinics in Taiwan. We examined the attitudes toward serum screening and the possible implications in women with positive results. From January to July 1995, 276 women were referred to the Genetic Counseling Clinic, Mackay Memorial Hospital for amniocentesis because of positive screening results, and 214 participated in this study. All women opted for amniocentesis after genetic counseling. Over 40% stated that they made decisions independently after being informed of the serum screening. Need for certainty was the most frequently mentioned reason. Two-thirds believed that serum screening could provide a diagnosis. Almost all women would apply for maternal serum screening for future pregnancies. This study demonstrated that Chinese women need more counseling and autonomy regarding maternal serum screening.  相似文献   
168.
We examined the effects of exposure to violence and social support on self-reported state and trait anxiety and parental rated problem behaviors among school-aged African-American children in low and high violence areas. Ninety-seven (97) fourth through sixth graders and their parents were interviewed about exposure to community violence, social support, and state and trait anxiety. Results indicate that trait anxiety was correlated positively with exposure to violence and negatively with social support. State anxiety was correlated negatively with family social support. Problem behaviors were correlated negatively with family support and income. Hierarchial multiple regression analyses indicated that children's reports of their exposure to community violence continued to explain significant variability in trait anxiety, and problem behavior after controlling for both income and social support measures. Social support from peers, family and teachers played differential roles in predicting problem behaviors among children from high and lower violence areas. These findings suggest that in planning intervention programs for children exposed to violence, greater attention to empowering parents to support their children, to fostering peer group support, and to bolstering teacher support may be useful, but attention to the underlying socio-political causes of violence exposure is essential.  相似文献   
169.
We investigated the separate and combined effects of a behavioral intervention and methylphenidate (Ritalin®) on disruptive behavior and task engagement in 3 children with severe to profound mental retardation. The behavioral intervention involved differential reinforcement of appropriate behavior and guided compliance. All 3 children demonstrated decreased disruptive behavior and improved task engagement in response to the behavioral intervention. Two of the 3 children demonstrated similar improvement in response to methylphenidate. Although both interventions were highly effective for these 2 participants, the relative efficacy of the interventions varied between the 2 children. There was no evidence of an additive or synergistic effect of the two interventions, but the high efficacy of each intervention alone limited our ability to detect such effects.  相似文献   
170.
Data from rodent studies have indicated that stress experienced by pregnant mothers may result in behavioral and biological abnormalities in their offspring. However, few studies have examined the effects of prenatal stress on the offspring beyond the childhood period. In this study, 7 prenatally stressed (PNS) monkeys and 7 monkeys from undisturbed pregnancies were tested under mildly challenging conditions at 4 years of age. Following separation from cagemates and group formation, PNS monkeys showed more locomotion, abnormal and disturbance behavior than controls. Controls showed approximately six times more play than PNS animals. The PNS males showed the most clinging to others and the largest increase in contact with other animals over the period. Group differences were also found when the monkeys were observed as groups or alone in a playroom. Controls showed more explanatory behavior in the playroom, whereas PNS monkeys showed more inactivity. Control animals showed a decrease in distress vocalizations over time in the playroom, whereas PNS animals showed the opposite pattern. Control animals spent more time in proximity to and contact with cagemates than PNS animals. These results indicate that prenatal stress can have effects on adaptive and social behavior that persist into adolescence.  相似文献   
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