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   35855篇
  免费   1493篇
  国内免费   18篇
  37366篇
  2020年   356篇
  2019年   418篇
  2018年   608篇
  2017年   613篇
  2016年   664篇
  2015年   507篇
  2014年   593篇
  2013年   2743篇
  2012年   1058篇
  2011年   1042篇
  2010年   667篇
  2009年   629篇
  2008年   868篇
  2007年   939篇
  2006年   804篇
  2005年   786篇
  2004年   708篇
  2003年   665篇
  2002年   714篇
  2001年   1334篇
  2000年   1283篇
  1999年   946篇
  1998年   378篇
  1997年   344篇
  1996年   373篇
  1992年   781篇
  1991年   750篇
  1990年   739篇
  1989年   670篇
  1988年   668篇
  1987年   633篇
  1986年   604篇
  1985年   615篇
  1984年   514篇
  1983年   456篇
  1982年   348篇
  1981年   324篇
  1979年   544篇
  1978年   415篇
  1977年   347篇
  1975年   451篇
  1974年   563篇
  1973年   572篇
  1972年   455篇
  1971年   444篇
  1970年   411篇
  1969年   419篇
  1968年   542篇
  1967年   478篇
  1966年   428篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
891.
Phonetic segments are coarticulated in speech. Accordingly, the articulatory and acoustic properties of the speech signal during the time frame traditionally identified with a given phoneme are highly context-sensitive. For example, due to carryover coarticulation, the front tongue-tip position for HI results in more fronted tongue-body contact for a /g/ preceded by /l/ than for a /g/ preceded by /r/. Perception by mature listeners shows a complementary sensitivity—when a synthetic /da/-/ga/ continuum is preceded by either /al/ or /ar/, adults hear more /g/s following HI rather than Irl. That is, some of the fronting information in the temporal domain of the stop is perceptually attributed to /l/ (Mann, 1980). We replicated this finding and extended it to a signaldetection test of discrimination with adults, using triads of disyllables. Three equidistant items from a /da/-/ga/ continuum were used preceded by /al/ and /ar/. In the identification test, adults had identified item ga5 as “ga”, and dal as “da”, following both /al/ and /ar/, whereas they identified the crucial item d/ga3 predominantly as “ga” after /al/ but as “da” after /ar/. In the discrimination test, they discriminated d/ga3 from dal preceded by /al/ but not /ar/; compatibly, they discriminated d/ga3 readily from ga5 preceded by /ar/ but poorly preceded by /al/. We obtained similar results with 4-month-old infants. Following habituation to either ald/ga3 or ard/ga3, infants heard either the corresponding ga5 or dal disyllable. As predicted, the infants discrimi-nated d/ga3 from dal following /al/ but not /ar/; conversely, they discriminated d/ga3 from ga5 following /ar/ but not /al/. The results suggest that prelinguistic infants disentangle consonant-consonant coarticulatory influences in speech in an adult-like fashion.  相似文献   
892.
Growth systematically changes the body proportions of both humans and animals so that the ratio of head height to body height decreases with age. Prior studies have demonstrated that body proportions provide effective information for age perception. To test the proposal that illustrators incorporate this information into their drawings, measurements were made of the head and body heights of 100 pairs of animals appearing in children’s picture books. In 93 pairs, the animal intended to be perceived as older had a smaller head-to-body ratio than did the younger animal. Ratings collected for 25 of these pairs showed that both perceived age and cuteness are significantly correlated with body proportions. The magnitudes of the correlations were only modest, suggesting that other aspects of the drawings influenced perceived age and cuteness. In addition, observers reported that body proportions are only one of a variety of factors influencing age and cuteness perception. As has been found in other studies, perceived age and cuteness were negatively correlated.  相似文献   
893.
State lawmakers in Virginia recently approved a measure to limit to one the number of handguns a person can purchase within a thirty day period. In the months preceding the law's approval, a survey was conducted to measure the level of public support for the proposed initiative. The results of the survey were provided to lawmakers and other high level government officials in an effort to provide policymakers with objective data for gauging support (or non-support) for the proposal. Past public opinion polls which have measured attitudes concerning gun control reveal differences in the levels of support with regard to such factors as individual gun ownership and region of residence. The following research reveals the sentiment of one State's citizenry toward a specific handgun control measure by focusing on how responses varied across selected sub-groups within the sample.  相似文献   
894.
Briefly stated my point is that the well-being of each person in a community conceived abstractly may be all too easily sacrificed for the sake of the abstraction. Physicians may offer critically ill patients places in programs of experimental treatment, but there is commonly a catch to the offer. To take part in a program of clinical experiment a patient must not only risk a possible failure of a fresh drug and the chance of destructive side effects from the drug, but the patients must risk only getting the traditional treatment along with a placebo rather than the experimental drug. Placebo control, double blind critical protocols for testing effects of fresh drugs on critically ill patients are a commonplace. I question the scientific objectivity of the protocols and the underlying ethic, and suggest use of alternate protocols. Experimental tests in the treatment gram-negative bacteria blood infections, muscular dystrophy, and AIDS and AIDS-related diseases are examples.  相似文献   
895.
This article reviews the results of survey methodological research that illustrate phenomena of potential interest to investigators of memory, and also reviews psychological research designed to explore some of these phenomena under controlled laboratory conditions. We classify the phenomena reviewed into broad categories of remembering what events occurred, remembering when events occurred, and estimation and reconstruction processes used in reporting recurring events. We delineate the contributions of this research for our understanding of memory phenomena and show where this research has revealed gaps in our existing theories and knowledge. These findings present challenges for future collaboration between cognitive psychologists and survey methodologists.  相似文献   
896.
897.
This study explores Black teachers' preferences for and ratings of consultant effectiveness as a function of consultant race, consultant style, and teacher stage of racial identity development. No significant differences were noted in preferences for either a same- or opposite-race consultant. Participants preferred and rated as more effective an instrumentally oriented consultant.  相似文献   
898.
This study examined the effects of neurolinguistic mirroring versus nonmirroring of selected nonverbal behaviors on empathy, trustworthiness, and positive interaction in a cross-cultural setting among 60 Choctaw adolecents and Caucasian female counselors. Results indicated significant mirroring effects on the empathy scale of the Barrett-Lennard Relationship Inventory.  相似文献   
899.
People become subject to political and social violence when governments fail to give priority to basic health care or education. Attempts to meet foreign obligations also produce severe economic recessions which further impede efforts to improve the general quality of life of disadvantaged populations. Since multiple factors contribute to violence, a multidisciplinary approach is best suited to address the problem. For example, poverty and its associated risks are linked to violence, but living in poverty does not necessarily engender violence. Living in poverty may, however, fuel high rates of child mortality, illiteracy, malnutrition, excessive population growth, street children, and familial disintegration. An integrated action program was developed in Brazil for at-risk individuals and their families based upon the idea of building and reinforcing family ties and intergenerational togetherness. Undernourished infants, street children, the handicapped, women subjected to violence, and neglected senior citizens received special interventions in the program described in the text.  相似文献   
900.
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