全文获取类型
收费全文 | 2707篇 |
免费 | 45篇 |
国内免费 | 2篇 |
专业分类
教育 | 1840篇 |
科学研究 | 313篇 |
各国文化 | 18篇 |
体育 | 215篇 |
综合类 | 9篇 |
文化理论 | 18篇 |
信息传播 | 341篇 |
出版年
2022年 | 21篇 |
2021年 | 23篇 |
2020年 | 28篇 |
2019年 | 47篇 |
2018年 | 54篇 |
2017年 | 87篇 |
2016年 | 76篇 |
2015年 | 64篇 |
2014年 | 69篇 |
2013年 | 567篇 |
2012年 | 67篇 |
2011年 | 68篇 |
2010年 | 54篇 |
2009年 | 38篇 |
2008年 | 55篇 |
2007年 | 56篇 |
2006年 | 44篇 |
2005年 | 36篇 |
2004年 | 44篇 |
2003年 | 37篇 |
2002年 | 31篇 |
2001年 | 30篇 |
2000年 | 48篇 |
1999年 | 56篇 |
1998年 | 27篇 |
1996年 | 28篇 |
1995年 | 17篇 |
1994年 | 19篇 |
1993年 | 29篇 |
1992年 | 30篇 |
1991年 | 45篇 |
1990年 | 49篇 |
1989年 | 44篇 |
1988年 | 34篇 |
1987年 | 26篇 |
1986年 | 36篇 |
1985年 | 48篇 |
1984年 | 39篇 |
1983年 | 30篇 |
1982年 | 33篇 |
1981年 | 25篇 |
1980年 | 23篇 |
1979年 | 30篇 |
1978年 | 35篇 |
1977年 | 25篇 |
1976年 | 23篇 |
1974年 | 24篇 |
1971年 | 20篇 |
1968年 | 28篇 |
1967年 | 24篇 |
排序方式: 共有2754条查询结果,搜索用时 125 毫秒
21.
I. I. Potapov 《Scientific and Technical Information Processing》2018,45(2):63-69
Modern global eco-dynamics problems are discussed. It is noted that global changes are mostly characterized by several key features, such as their multicomponent nature, as well as interactivity and nonlinearity. These features challenge various forecast estimates in such a way that the concept of forecasting has been replaced over the last few years by a much more ambiguous concept of scenarios. The vagueness of scenarios is due to the problem of global climate change. A global climate–nature–society system model is outlined. 相似文献
22.
I. V. Zibareva L. Yu. Ilina B. L. Alperin 《Scientific and Technical Information Processing》2018,45(2):106-109
The current state of the Russian Science Citation Index is analyzed. Several areas for its further development identified by long-standing active users, such as data searching, refinement, and storage; current user alerts; data input with the Science Index license; patent information; and the application programming interface (API) are investigated. 相似文献
23.
Miller LE Pierson LM Nickols-Richardson SM Wootten DF Selmon SE Ramp WK Herbert WG 《Research quarterly for exercise and sport》2006,77(1):58-63
This study assessed muscular torque and rate of torque development following concentric (CON) or eccentric (ECC) isokinetic training. Thirty-eight women were randomly assigned to either CON or ECC training groups. Training consisted of knee extension and flexion of the nondominant leg three times per week for 20 weeks (SD = 1). Eccentric training increased ECC knee extension and flexion peak torque more than CON training. The ECC group improved acceleration time and time to peak torque with ECC movements versus the CON group. Slow-velocity ECC isokinetic training yielded greater ECC and similar CON torque development gains versus CON training over the course of 20 weeks in young women. 相似文献
24.
The aim of this study was to examine the relationship between indicators of risk of disordered eating, body image and varied menstrual cycle lengths. Altogether, 151 female athletes were invited from 16 sports and 70 female non-athletic controls were recruited from a university lecture class. The participants completed several surveys, including demographics, menstrual cycle history, physical activity, Eating Disorder Inventory (EDI) and the Three Factor Eating Questionnaire (TFEQ). Selected EDI subscales were summed to reflect eating disorder risk and body image. Menstrual cyclicity was based on self-reported cycle length for the last 6 months (normal cycles = 26-32 days, irregular cycles < or =26 or >32 days). Athletes overall had more irregular cycles (29.1%) than the non-athletes (15.7%) (P < 0.05). There were significant differences in scores for eating disorder risk, body dissatisfaction, drive for thinness, cognitive restraint (TFEQ) and disinhibition (TFEQ), only when athletes were divided based on menstrual cyclicity (i.e. irregularly cycling athletes had higher scores than athletes with normal menstrual cycle lengths). No differences in these scores were found between non-athletes with normal or irregular menstrual cycle lengths. In conclusion, irregularly short or long menstrual cycle length is associated with subtle indications of higher risk of disordered eating in female athletes. 相似文献
25.
The aim of the present study was to assess the effects of motivating and oudeterous (neither motivating nor demotivating) synchronous music on 400-m sprint performance while controlling for the potential confound of pre-performance mood. A panel of volunteer Caucasian males (n = 20; mean age = 20.5 years, s = 1.2) rated the motivational qualities of 32 musical selections using the Brunel Music Rating Inventory-2. An experimental group of volunteer Caucasian males (n = 36; mean age = 20.4 years, s = 1.4) completed three 400-m time trials under conditions of motivational music, oudeterous music, and a no-music control. Pre-performance mood was assessed using the Brunel University Mood Scale (BRUMS). A series of repeated-measures analyses of variance with Bonferroni adjustment revealed no differences in the BRUMS subscales. A repeated-measures analysis of variance on the 400-m times showed a significant effect (F1.24, 42.19 = 10.54, P < 0.001, eta 2 = 0.24) and follow-up pair wise comparisons revealed differences between the synchronous music conditions and the control condition. This finding supported the first research hypothesis, that synchronous music would result in better performance than a no-music control, but not the second hypothesis, that performance in the motivational synchronous music condition would be better than that in the oudeterous condition. It appears that synchronous music can be applied to anaerobic endurance performance among non-elite sports persons with a considerable positive effect. 相似文献
26.
27.
The classical criteria for controllability and observability are given a tensorial formulation which is then extended into Boolean form directly related to a digraph interpretation of system structure. This is examined in detail with particular reference to group theoretic aspects, invariant properties under transformation, the term rank test and the existence of zero eigenvalues.Within this framework the structural design concepts of potential controllability and observability are presented in generalised terms. 相似文献
28.
The graph theoretic aspects of controllability and observability are examined and related to the tensorial formulation of Part I of the paper. Particular emphasis is given to the significance of the system digraph decomposition and the relevance of this to certain system algebraic properties of interest in control theory. 相似文献
29.
A sequence of tests on derived polynomials to be strictly Hurwitz polynomials is shown to be equivalent to a given (typically real) polynomial having all its zeros in an open sector, symmetric with respect to the real axis, in the left half-plane. The number of tests needed is at most 1 + ?(ln k)/(ln 3)?, where k is the integer associated with the central angle π/k of the sector. An extension of this result on the sector as a region of root clustering is given which shows that only a limited number of tests are needed to verify that the roots are clustered in a region composed as the intersection of a set of primative (sector-like) regions. The results reported evolve from application of a collection of mappings on the complex plane defined by a particular collection of Schwarz-Christoffel transformations. 相似文献
30.
Black and white male schoolchildren covertly evaluated their own performance at a verbal task administered by black and white male experimenters. It was hypothesized that academically successful children would be predisposed to appraise themselves favorably, whereas relatively unsuccessful pupils would be biased toward self-criticism. The covert self-evaluations were assumed to represent at internalization of early experiences of predominantly positive or negative social reinforcement from adult socializing agents. The predicition for self-criticism was upheld in the white experimenter condition but not in the black experimenter condition. Relationships consistent with the theory were found between subjects' self-appraisals and their retrospective reports of positive and negative reinforcements received from parents and teachers in various typical situations. These relationships were more evident for black subjects than for white subjects. The extent to which children's self-praise and self-criticism mediated affect was assessed by means of a color conditioning technique. Contrary to predicition, possibly due to the easy nature of the experimental task. 相似文献