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   187928篇
  免费   8335篇
  国内免费   155篇
  196418篇
  2020年   2776篇
  2019年   3440篇
  2018年   3657篇
  2017年   4096篇
  2016年   4699篇
  2015年   3927篇
  2014年   4802篇
  2013年   23435篇
  2012年   4974篇
  2011年   4276篇
  2010年   4089篇
  2009年   4852篇
  2008年   4408篇
  2007年   4034篇
  2006年   4481篇
  2005年   4388篇
  2004年   3872篇
  2003年   3464篇
  2002年   3323篇
  2001年   4044篇
  2000年   3909篇
  1999年   3655篇
  1998年   2890篇
  1997年   2726篇
  1996年   2639篇
  1995年   2452篇
  1994年   2412篇
  1993年   2386篇
  1992年   3036篇
  1991年   2843篇
  1990年   2686篇
  1989年   2547篇
  1988年   2532篇
  1987年   2521篇
  1986年   2557篇
  1985年   2754篇
  1984年   2748篇
  1983年   2496篇
  1982年   2444篇
  1981年   2417篇
  1980年   2247篇
  1979年   2525篇
  1978年   2327篇
  1977年   2245篇
  1976年   2048篇
  1975年   2236篇
  1974年   2311篇
  1973年   2245篇
  1972年   1829篇
  1971年   1724篇
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
951.
This study investigates whether language-impaired (LI) children show deficits in rapid automatized naming and whether RAN performance is specific to verbal output (or to rapid motor output in general). A total of 67 LI and 54 age-matched control children were tested with the Rapid Automatized Naming (RAN) test (Denckla & Rudel, 1976) and with a manual version of the RAN (RAN-manual) in which subjects were required to provide a nonverbal, pantomime response. Subjects also completed tests of rapid oral and manual sequencing skills and standardized tests of reading ability. Each subject was tested at 4, 6, and 8 years old. The results showed that LI children perform significantly poorer on both versions of the RAN than age-matched controls. Correlations between RAN scores and tests of reading ability were significant for normal and LI subjects and were particularly high for 8-year-old LI children. RAN-manual scores also correlated with 8-year-old LI children's reading scores. Further, RAN and RAN-manual scores for the LI children correlated significantly with these children's manual sequencing abilities, whereas this was not the case for the control subjects. These findings suggest that LI children's rapid sequential processing deficits are not limited to verbal output, but also generalize to other motoric domains.  相似文献   
952.
953.
There is evidence of two major components of grammatic function in the brain: (1) morphologic, probably based in the postcentral perisylvian cortex, encompassing the selection of individual words and inflectional endings according to the rules of grammar; and (2) syntactic, probably based in the frontal lobes, encompassing construction of the overall structure of a sentence (syntax) to match the concept being considered. We present a stroke patient with impaired morphology but, unlike Broca's aphasics, relative sparing of syntax. He omitted 43% of articles, 40% of complementizers, 20% of pronouns, 27% of semantically marked prepositions, 43% of purely grammatic prepositions, and 22% of auxiliary verbs, but his average sentence length was 9.8 words and 64% of his sentences contained embedded clauses. He frequently intermingled two sentences to convey a given concept, juxtaposing words in grammatically unacceptable ways. This intermingling may represent either a grammatic "conduite d'approche," or a failure of the filtering function of a defective morphologic processor. His great difficulty in completing syntactic frames suggests that a more general form of the processes underlying grammatic morphology may play an important role in phrase structure generation.  相似文献   
954.
We assessed the usefulness of the Western Aphasia Battery for distinguishing the language disturbances caused by Alzheimer dementia (AD) from those caused by stroke. Using discriminant function analyses, the multiple variable "aphasia quotient--reading quotient--writing quotient" classified 29 (72.5%) of the 40 patients correctly. These 29 patients included 8 of 10 patients with left hemisphere infarction and fluent aphasia; 6 of 10 with AD; 5 of 10 patients with right hemisphere infarction; and all 10 of the neurologically normal control subjects. The patients with AD and those with right hemisphere stroke were the most difficult to classify using the aphasia battery.  相似文献   
955.
956.
957.
We measured subjective-tone identification thresholds evoked by acoustically filtered complex tones and compared them to Mandarin-Chinese tone-phoneme identification thresholds previously measured under the same filtering conditions. Tone phonemes were identified at intensities below subjective-tone identification thresholds, suggesting subjective tone is not necessary for tone-phoneme identification. Lower subjective-tone thresholds evoked by resolved harmonics rather than unresolved harmonics were consistent with pattern recognition theories of pitch perception.The authors thank Donald Gans and Richard Klich for all their help.  相似文献   
958.
Analyzed case records to determine the costs and service usage patterns for a group of 25 youth randomly selected from the case load of a regional mental health agency. Study participants had extensive histories of publicly supported psychiatric hospitalizations. An average of 36.2 contacts per youth (905 total contacts) with human services providers were documented. Approximately 2 out of every 5 contacts resulted in out-of-home placements. The estimated cost of providing services to the 25 youth exceeded 3 million dollars. The types and costs of treatment services provided to study participants are discussed.  相似文献   
959.
Examined the effects of precautionary behavior on subsequent criminal victimization, fear of crime, and psychological distress. A sample of 538 adults was interviewed three times at 6-month intervals. Four different aspects of precaution were assessed: vigilance (alertness), locks (access control), neighbors (informal cooperation), and professionals (formal programs). In logistic regressions that controlled for 14 risk factors, precaution had no preventive effects on the occurrence of subsequent crimes. LISREL models revealed that use of neighbors was the only precaution not to increase fear of crime, although both locks and neighbors showed a capacity to buffer the effects of fear on generalized distress. It was concluded that the most promising strategy was protective neighboring. Altogether, however, the promotion of citizen-initiated prevention appears highly inadequate as a policy response to problems of crime and fear.  相似文献   
960.
Investigated predictors of five measures of early school adjustment for an ethnically diverse cohort of 683 inner-city kindergartners and first graders. Data from 2 consecutive years were collected from teachers, school records, and children. A multiple-regression preduction model significantly explained children's competence behavior, problem behavior, reading achievement, mathematics achievement, and school absences. Prior adjustment and sociodemographic factors explained a majority of the variance in adjustment. Perceived quality of parent involvement was signifcantly related (in the expected direction) to all five outcomes. Exposure to life events was significantly associated in the expected direction with competence behavior, problem behavior, and school absences but not with reading and mathematics achievement. Together, parent involvement and life-event variables explained as much as 12% of the variance in adjustment independent of sociodemographic and prior adjustment factors. The role of family and school factors in the adjustment of children at risk is discussed [corrected].  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