全文获取类型
收费全文 | 6055篇 |
免费 | 35篇 |
国内免费 | 1篇 |
专业分类
教育 | 4199篇 |
科学研究 | 842篇 |
各国文化 | 15篇 |
体育 | 293篇 |
综合类 | 8篇 |
文化理论 | 119篇 |
信息传播 | 615篇 |
出版年
2022年 | 22篇 |
2021年 | 23篇 |
2020年 | 27篇 |
2019年 | 53篇 |
2018年 | 754篇 |
2017年 | 783篇 |
2016年 | 557篇 |
2015年 | 105篇 |
2014年 | 82篇 |
2013年 | 421篇 |
2012年 | 138篇 |
2011年 | 375篇 |
2010年 | 358篇 |
2009年 | 196篇 |
2008年 | 263篇 |
2007年 | 371篇 |
2006年 | 43篇 |
2005年 | 112篇 |
2004年 | 194篇 |
2003年 | 130篇 |
2002年 | 62篇 |
2001年 | 33篇 |
2000年 | 62篇 |
1999年 | 56篇 |
1998年 | 23篇 |
1997年 | 28篇 |
1996年 | 21篇 |
1995年 | 16篇 |
1993年 | 14篇 |
1992年 | 22篇 |
1991年 | 34篇 |
1990年 | 45篇 |
1989年 | 34篇 |
1988年 | 32篇 |
1987年 | 21篇 |
1986年 | 34篇 |
1985年 | 40篇 |
1984年 | 34篇 |
1983年 | 28篇 |
1982年 | 26篇 |
1981年 | 22篇 |
1980年 | 18篇 |
1979年 | 29篇 |
1978年 | 29篇 |
1977年 | 21篇 |
1976年 | 18篇 |
1974年 | 17篇 |
1971年 | 17篇 |
1970年 | 14篇 |
1968年 | 19篇 |
排序方式: 共有6091条查询结果,搜索用时 0 毫秒
81.
82.
The term noise is used to describe fluctuations about the mean deterministic stationary value of a physical quantity. It is
now being increasingly realised that noise is an important ingredient to bring order in dynamical processes. Though it appears
counterintuitive, noise seems to help in directing transport processes in biological systems at the molecular level. In Part
2 of the article, we discuss some more examples of noise assisted directed motion. 相似文献
83.
This study investigated patterns of college attendance using data from a nationwide and contemporary sample of 2112 rural youth. We found that more than half of rural youth attended two-year institutions at some point during their college career and about a fourth initially enrolled in a two-year college before enrolling in a four-year college. Results also revealed that parental education, college preparatory track and preparation experiences, and teacher expectations predicted students’ college attendance patterns. Our findings point to the importance of two-year colleges and highlight the influence of family characteristics and students’ schooling experiences in the postsecondary trajectories of rural youth. 相似文献
84.
This article investigates how culture shapes instruction in three early care and education programs on the Flathead Indian Reservation. Interviews with eight early childhood teachers as well as classroom observations were conducted. The investigation is framed by the following research question: How does the culture of the family and community shape curriculum? Data analysis suggested that ongoing communication with parents and community about teaching within a culturally relevant context, building a sense of belongingness and community through ritual, and respecting children, families, and community were essential to defining the Native American Indian culture within these early learning programs. 相似文献
85.
The Youth in Transition Survey is used to follow the postsecondary education (PSE) pathways and outcomes of Canadian youth over the mid 2000s. Students starting at community colleges and four year universities are analyzed separately. First program outcomes are reported, showing the proportions of students who leave their first programs but remain in PSE by switching/transferring to other programs, institutions, or levels. Multinomial regression estimates correlates of students’ first program switching and leaving decisions. Five year graduation rates are calculated to show the importance of different pathways (across programs, institutions, and levels) to earning a PSE credential; in the aggregate and for subgroups of students. Transfers constitute important but not terribly large pathways for Canadian students to adjust their PSE and obtain PSE credentials. We calculate the resulting extent to which institution specific measures of persistence, PSE leaving, and graduation rates misstate the rates experienced by students. Compared to American students, university and community college starters in Canada have higher persistence and graduation rates and lower transfer rates across institutions. For community college starters, much of the difference is due to the relative lack of well defined pathways from community colleges to universities in Canada. We find that students with more family resources are better able to transfer across programs or institutions in order to obtain a PSE credential. 相似文献
86.
Marcee M. Steele 《Early Childhood Education Journal》2004,32(2):75-79
The early identification of children with learning disabilities (LD) is difficult but can be accomplished. Observation of key behaviors which are indicators of LD by preschool and kindergarten teachers can assist in this process. This early identification facilitates the use of intervention strategies to provide a positive early experience for children at risk for academic difficulties. 相似文献
87.
Parental reactions to children's negative emotions: longitudinal relations to quality of children's social functioning 总被引:7,自引:0,他引:7
Relations between self-reported parental reactions to children's negative emotions (PNRs) and children's socially appropriate/problem behavior and negative emotionality were examined longitudinally. Evidence was consistent with the conclusion that relations between children's externalizing (but not internalizing) emotion and parental punitive reactions to children's negative emotions are bidirectional. Reports of PNRs generally were correlated with low quality of social functioning. In structural models, mother-reported problem behavior at ages 10-12 was at least marginally predicted from mother-reported problem behavior, children's regulation, and parental punitive or distress reactions. Moreover, parental distress and punitive reactions at ages 6-8 predicted reports of children's regulation at ages 8-10, and regulation predicted parental punitive reactions at ages 10-12. Father reports of problem behavior at ages 10-12 were predicted by earlier problem behavior and parental distress or punitive reactions; some of the relations between regulation and parental reactions were similar to those in the models for mother-reported problem behavior. Parental perceptions of their reactions were substantially correlated over 6 years. Some nonsupportive reactions declined in the early to mid-school years, but all increased into late childhood/early adolescence. 相似文献
88.
Urinary citric acid and calcium levels have been estimated in the urine of 20 normal healthy persons as well as 12 urinary
stone patients. Inhibition efficiency of these urine samples towards the mineralisation of urinary stone forming minerals,
viz., calcium phosphate, oxalate or carbonate, has been studied in an experimental model. Statistical correlation of the above
data has been made by computing the coefficient of determination and unexplained variance. Clinico-biochemical indexing of
calcium urolithiasis risk factor has been attempted in the light of the data. 相似文献
89.
K. A. Faseehuddin Shakir Basavaraj Madhusudhan 《Indian journal of clinical biochemistry : IJCB》2007,22(1):117-121
Rats fed with hypercholesterolemic diet showed a significant increase in serum total—cholesterol, liver homogenate total-cholesterol,
HDL-cholesterol and changed LDL-cholesterol, and HDL/LDL ratio in comparison to control. Flaxseedchutney (FC) supplemented diet (15%, w/w) was found to be more effective in restoring lipid profile changes in rats fed with cholesterol,
(1.0%). The activities of serum marker enzymes glutamate oxaloacetate transminase (GOT), glutamate pyruvate transaminase (GPT)
and alkaline phosphatase (ALP) were elevated significantly in carbon tetrachloride induced rats. Administration of flaxseedchutney (15%, w/w) resulted in depletion of serum marker enzymes and exhibited recoupment thus showing significant hepatoprotective
effect. It was observed that flaxseedchutney supplemented diet could lower the serum cholesterol and as a potential source of antioxidants it could exert protection against
hepatotoxic damage induced by carbon tetrachloride (CCl4) in rats. 相似文献
90.
K. Pratibha T. Seenappa K. Ranganath 《Indian journal of clinical biochemistry : IJCB》2007,22(2):158-161
Alkaptonuria, a metabolic disorder characterized by a triad of homogentisic aciduria, arthritis and ochronosis is one of the
first conditions in the charter of group of inborn errors of metabolism proposed to have Mendelian recessive inheritance.
It is due to the deficiency of the enzyme homogentisic acid oxidase which catalyzes the conversion of homogentisic acid to
maleylacetoacetic acid in the catabolism of tyrosine. Homogentisic acid thus accumulates in cells and body fluids and its
oxidized polymers bind to collagen, leading to progressive deposition of grey to bluish black pigment resulting in degenerative
changes in cartilage, intervertebral disc and other connective tissues, leading to arthritis which is the only disabling effect
in an affected older individual. However the diagnosis can be made in neonates when blackish stain is noticed in an unwashed
diaper. Alkaptonuria is treated symptomatically, surgical intervention necessitates in advanced stages, treatment with ascorbic
acid (Vitamin C) and dietary restrictions of food containing phenylalanine and tyrosine have proved to be successful in alleviating
the symptoms. 相似文献