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   30108篇
  免费   1367篇
  国内免费   27篇
  2021年   248篇
  2020年   429篇
  2019年   496篇
  2018年   700篇
  2017年   697篇
  2016年   729篇
  2015年   538篇
  2014年   639篇
  2013年   2809篇
  2012年   1151篇
  2011年   1257篇
  2010年   744篇
  2009年   753篇
  2008年   1015篇
  2007年   986篇
  2006年   943篇
  2005年   835篇
  2004年   795篇
  2003年   803篇
  2002年   800篇
  2001年   941篇
  2000年   911篇
  1999年   673篇
  1998年   372篇
  1997年   375篇
  1996年   320篇
  1995年   299篇
  1994年   268篇
  1993年   290篇
  1992年   493篇
  1991年   473篇
  1990年   477篇
  1989年   446篇
  1988年   401篇
  1987年   399篇
  1986年   436篇
  1985年   450篇
  1984年   393篇
  1983年   331篇
  1982年   252篇
  1981年   271篇
  1979年   295篇
  1978年   277篇
  1977年   236篇
  1976年   230篇
  1975年   280篇
  1974年   342篇
  1973年   281篇
  1972年   257篇
  1969年   237篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
991.
Multiple baseline designs were used to examine the effects of an instructional package on accuracy of performance in solving multiplication facts by 3 students with learning disabilities. The instructional package included the following components: (a) a modified instructional sequence in which multiplication facts were grouped into the zeros, ones, doubles, fives, and nines categories, and those remaining; (b) identification of the category in which each fact belonged; (c) mnemonic strategies associated with solving facts in each category; and (d) steps to be completed for solving facts in each category. Results indicated that the instructional package produced substantial and immediate effects. After receiving instruction, a participant's accuracy was often 100%, and this was maintained throughout the evaluation even as other strategies were introduced. Comparable results occurred across students, demonstrating replication of the effects of the instructional package.  相似文献   
992.
The associations between early onset (prior to 15 years of age) cannabis use and rates of mental health or adjustment problems during the period from 15 to 16 years of age were studied in a New Zealand birth cohort. Early onset cannabis users were at increased risks of later substance use behaviors, conduct/oppositional disorders, juvenile offending, severe truancy, school dropout, anxiety, depression, and suicidal ideation. Early cannabis users had odds of these outcomes ranging from 2.7 to 30.8 times higher than the odds for those who did not use cannabis prior to age 15. Most of the elevated risks of early onset users were explained by the fact that they were a high-risk group of adolescents characterized by family disadvantages, early adjustment problems, and high affiliations with substance-using or delinquent peers. Nonetheless, even after adjustment for a wide range of confounding factors, early onset users had increased risks of later cannabis use. It is concluded that while most of the elevated risks of early onset users were explained by social, family, and individual characteristics of this group, early onset users were at increased risks of later cannabis use.This research was funded by grants from the Health Research Council of New Zealand, the National Child Health Research Foundation and the Canterbury Medical Research Foundation.  相似文献   
993.
To determine the relative impact of a number of family variables on children's performance of gender-typed household tasks, this study took account of the gender of the child, the gender of a sibling within the same age range (8–14 years), whether a first or second child and three parental variables: the degree of encouragement given to perform masculineand femininetasks, parental involvement in the same tasks, and parents' general egalitarianism. The sample consisted of 191 white, mainly Anglo Australian two-parent families, with the two oldest children in a boy—boy, girl—girl, boy—girl, or girl—boy sequence. To check on the robustness of effects, measures were taken on two occasions, on average 16 months apart. Among the family context variables, the gender of the child was the strongest contributing variable, with girls doing more feminine tasks than boys and boys doing more masculine tasks than girls. There was limited support for the proposition that first children do more housework than second children of the same gender, while the results for gender of sibling were small and inconsistent. Among the parental variables, encouragement had strong positive effects for feminine tasks (i.e., more encouragement by parents corresponded to more involvement by children). In contrast, parental involvement in the same tasks (modeling) and parental egalitarianism predicted only the performance of masculine tasks, and the direction of the effects was mostly negative (e.g., the more a father was involved in masculine tasks, the less a child did of those tasks). The results point to involvement in gender-typed activities being influenced by multiple factors, with parental encouragement and gender of child being most prominent among these. They also point to the value of sampling on more than one occasion and of considering separately the performance of feminine and masculine tasks. This research was financially supported by the Australian Research Council. We are happy to acknowledge that support, together with the essential assistance of the Department of Education and the many parents and children who participated in the study.  相似文献   
994.
FEMALE PARTNERS OF BISEXUAL MEN What They Don't Know Might Hurt Them   总被引:2,自引:0,他引:2  
Individual interviews with 350 behaviorally bisexual men aged 18–30 revealed that 71% of their female sexual partners and 59% of their steady female sexual partners in the past 6 months had not been aware of their homosexual activity. Rates of nondisclosure were higher for African-American than White men. Compared to nondisclosers, men who disclosed to all their female partners were less self-homophobic and perceived their friends, families, and neighbors as more accepting of their homosexual behavior. Compared to men who had disclosed, the nondisclosers had more female partners and used condoms less consistently with women.  相似文献   
995.
Harsh K. Luthar 《Sex roles》1996,35(5-6):337-361
This laboratory experiment involved 290 undergraduate seniors (130 females and 160 males) who were taking the capstone course in business policy in the college of business at a large university. The population of business seniors from which the random sample was drawn consisted of approximately 3.7% African Americans, 7% Asians, 1% Hispanics, and 88.3% white Americans. The study investigated the impact of autocratic and democratic leadership styles on the perception of how well male and female managers perform as well as the leadership ability attributions made to them. It was found that, in general, democratic managers are perceived to be much higher performers, and superior leaders when compared to autocratic managers. There was some support for the gender contrast effect in that the autocratic female managers were perceived to be higher performers than autocratic male managers. Further, the study found support for the perceptual similarity thesis. Male subjects tended to evaluate other male managers higher while female subjects were partial to female managers in their evaluations. In particular, female subjects gave autocratic male managers very low evaluations on performance and judged them to be inferior leaders. The female subjects, however, gave female autocratic managers substantially higher evaluations in terms of both performance and leadership ability.  相似文献   
996.
997.
This study was designed to examine the relationship between gender role orientation and psychological adjustment during pregnancy and the postpartum period in a large sample of French-speaking Caucasian mothers. Gender role was assessed with the Bem Sex Role Inventory, which classifies subjects into four categories: androgynous, masculine, feminine, and undifferentiated. A discriminant analysis showed a relationship between androgyny and the following measures of psychological adaptation: self-esteem, satisfaction with social support, and level of apprehension toward perinatal stressors. The masculine gender role was linked with self-esteem, work involvement, age, and severity of perinatal stress. No relationship was found between gender role and the level of antenatal or postnatal depressive symptomatology. Stress, marital support, and social support were among the predictors of postpartum depression, which underlined the importance of taking these variables into account when studying the well-being of mothers during the postnatal period. Results are discussed in light of previous literature on the association between gender role and motherhood. The limitations of Bem's model and inventory are also considered.  相似文献   
998.
The aim of this study is to provide further characterization of a subgroup of so-called “Grammatical specific language-impaired (SLI)” children. The Grammatical SLI children have a persistent and disproportionate impairment in grammatical comprehension and expression of language. Previous research has indicated that their language impairment may be characterized by a domain-specific and modular language deficit. This study provides an initial investigation as to whether there is a genetic basis underlying their disorder as has been found for other forms of SLI and for SLI in general. The incidence of familial aggregation of language impairment was investigated in 12 Grammatical SLI children (aged 9:3 to 12:10). A familial language impairment (LI) history was classified as positive if one or more of the probands' relatives had a history of a speech/language or reading/writing problem which required speech therapy or any other form of remedial help. Case history information provided an initial indication that the Grammatical SLI children had a significantly higher incidence of a positive familial LI history than could be expected by chance. A questionnaire provided evidence of a positive LI history in the first-degree relatives of the SLI probands and 49 normally developing control probands. The SLI probands had a clearly and significantly higher incidence of a positive familial LI history than the control probands (77.8 vs. 28.5%, respectively). The results are consistent with a genetic basis underlying Grammatical SLI. The pattern of impairment in the SLI probands' relatives is consistent with an autosomal dominant genetic inheritance. In contrast to the control probands, the SLI probands' impaired relatives did not show a male gender bias. Thus, the gene does not appear to be sex-linked. The data indicate that further research is warranted to investigate the nature of the LI in the relatives of the Grammatical SLI probands and the genetic characteristics of this subgroup. The implications for the biological, domain-specific, and modular bases to language are discussed.  相似文献   
999.
1000.
This paper discusses the notions of failure and mistakes in family therapy, arguing that there are insufficient accounts in the literature which reflect the untidiness and disorder of everyday practice. The idea of dominant and subjugated stories is invoked to map the influence of notions of failure upon family therapy practice. It is argued that our practice would benefit if more accounts of our work routinely included stories of failure, mistakes and regret.  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