全文获取类型
收费全文 | 15848篇 |
免费 | 212篇 |
国内免费 | 8篇 |
专业分类
教育 | 11597篇 |
科学研究 | 1304篇 |
各国文化 | 108篇 |
体育 | 1360篇 |
综合类 | 8篇 |
文化理论 | 130篇 |
信息传播 | 1561篇 |
出版年
2021年 | 153篇 |
2020年 | 244篇 |
2019年 | 390篇 |
2018年 | 522篇 |
2017年 | 522篇 |
2016年 | 472篇 |
2015年 | 289篇 |
2014年 | 378篇 |
2013年 | 3022篇 |
2012年 | 369篇 |
2011年 | 406篇 |
2010年 | 268篇 |
2009年 | 257篇 |
2008年 | 354篇 |
2007年 | 259篇 |
2006年 | 330篇 |
2005年 | 216篇 |
2004年 | 202篇 |
2003年 | 188篇 |
2002年 | 235篇 |
2001年 | 331篇 |
2000年 | 298篇 |
1999年 | 265篇 |
1998年 | 137篇 |
1997年 | 161篇 |
1996年 | 182篇 |
1995年 | 181篇 |
1994年 | 145篇 |
1993年 | 167篇 |
1992年 | 240篇 |
1991年 | 216篇 |
1990年 | 215篇 |
1989年 | 247篇 |
1988年 | 247篇 |
1987年 | 206篇 |
1986年 | 204篇 |
1985年 | 217篇 |
1984年 | 190篇 |
1983年 | 231篇 |
1982年 | 171篇 |
1981年 | 160篇 |
1980年 | 156篇 |
1979年 | 230篇 |
1978年 | 181篇 |
1977年 | 166篇 |
1976年 | 150篇 |
1975年 | 130篇 |
1974年 | 119篇 |
1973年 | 126篇 |
1971年 | 106篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Aaron J. Beach René E. D. Ferdinands Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):295-313
Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling. 相似文献
132.
Konstantinos D. Tambalis Demosthenes B. Panagiotakos Glykeria Psarra Stelios Daskalakis Stavros A. Kavouras Nickos Geladas 《European Journal of Sport Science》2016,16(6):736-746
The aim of the this study was to establish age- and gender-specific physical fitness normative values and to compare percentiles and Z scores values in a large, nationwide sample of Greek children aged 6–18 years. From March 2014 to May 2014, a total of 424,328 boys and girls aged 6–18 years who attended school in Greece were enrolled. The studied sample was representative, in terms of age–sex distribution and geographical region. Physical fitness tests (i.e. 20?m shuttle run test (SRT), standing long jump, sit and reach, sit-ups, and 10?×?5?m SRT) were performed and used to calculate normative values, using the percentiles of the empirical distributions and the lambda, mu, and sigma statistical method. Normative values were presented as tabulated percentiles for five health-related fitness tests based on a large data set comprising 424,328 test performances. Boys typically scored higher than girls on cardiovascular endurance, muscular strength, muscular endurance, and speed/agility, but lower on flexibility (all p values <0.001). Older boys and girls had better performances than younger ones (p?0.001). Physical fitness tests' performances tended to peak at around the age of 15 years in both sexes. The presented population-based data are the most up-to-date sex- and age-values for the health-related fitness of children and adolescents in Greece and can be used as standard values for fitness screening and surveillance systems and for comparisons among the same health-related fitness scores of children from other countries similar to Greece. Schools need to make efforts to improve the fitness level of the schoolchildren through the physical education curriculum to prevent cardiovascular risk. 相似文献
133.
Perceived health problems in swimmers according to the chemical treatment of water in swimming pools
Álvaro Fernández-Luna Pablo Burillo José Luis Felipe Julio del Corral Jorge García-Unanue Leonor Gallardo 《European Journal of Sport Science》2016,16(2):256-265
The objective of this study was to determine which chemical treatment used for disinfecting water in indoor swimming pools had the least impact on users' perceptions of health problems, and which generated the greatest satisfaction with the quality of the water. A survey on satisfaction and perceived health problems was given to 1001 users at 20 indoor swimming pools which used different water treatment methods [chlorine, bromine, ozone, ultraviolet lamps (UV) and salt electrolysis]. The findings suggest that there is a greater probability of perceived health problems, such as eye and skin irritation, respiratory problems and skin dryness, in swimming pools treated with chlorine than in swimming pools using other chemical treatment methods. Pools treated with bromine have similar, although slightly better, results. Other factors, such as age, gender, time of day of use (morning and afternoon) and type of user (competitive and recreational), can also affect the probability of suffering health problems. For all of the above, using combined treatment methods as ozone and UV, or salt electrolysis produces a lower probability of perceived health problems and greater satisfaction. 相似文献
134.
Walid Briki Keith D. Markman Guillaume Coudevylle Stéphane Sinnapah Olivier Hue 《European Journal of Sport Science》2016,16(3):350-357
The present study examined the influence of momentum sequence (positive vs. negative) and environmental climate (hot–wet vs. neutral) on supporters’ (i.e. virtual observers’) reported levels of perceived psychological momentum (PM) during a simulated cycling competition. Participants supported one of two competing cyclists involved in a race that was displayed on a screen in a lecture hall. The race scenario was manipulated so that the supported cyclist appeared to undergo either a positive or negative momentum sequence. In addition, participants were either exposed to a hot–wet environmental climate or to a neutral environmental climate while observing the race scenario. According to the results, reported levels of PM were higher in the positive momentum sequence condition than in the negative momentum sequence condition, consistent with the notion that supporters’ PM is influenced by a positivity bias, and reported levels of PM were also found to be higher in the hot–wet climate condition than in the neutral climate condition, consistent with the notion that environmental climate is a contextual factor that influences PM through the operation of a causal augmenting mechanism. 相似文献
135.
D P Sen Gupta 《Resonance》2007,12(3):54-69
Alternating Current (AC) is used all over the world today. In India we use AC at 50 Hz (cycles per second) and in USA and
Canada at 60 Hz. During the latter part of the 19th century, even during the early part of the 20th century, Direct Current
or DC was widely used. Had we continued with DC, electricity would not have been as widely available as it is today and its
use would have been cumbersome, costly and severely restricted. We owe it mainly to the Serbian genius Nikola Tesla that electricity
has reached almost every nook and corner of most continents. 相似文献
136.
Gerardo Blanco Ramírez 《International journal of qualitative studies in education》2016,29(2):186-204
Amidst global competition in higher education, colleges and universities adopt strategies that mimic and adapt business practices. Branding is now a widespread practice in higher education; multimodal advertisement is a manifestation of emerging branding strategies for universities. While the visibility of brands in higher education has grown substantially in recent years, its empirical study has lagged. This article reports on the findings from a study that employed social semiotic and multimodal analysis to explore text and visual rhetoric as brand construction strategies in publicly displayed university advertisements. After analyzing photographs representing advertising campaigns from 16 different universities displayed in an urban public transportation system, I suggest that universities construct their brand identity through messages that emphasize multiple choices and convenience, but construct success primarily according to corporate standards and values. 相似文献
137.
138.
1IntroductionRecent advances in wireless communication,digitallibrary,distributed multi media,massive storage,andmobile computing technologies are sti mulating the de-velopment of mobile multi media digital library systems(M2DLS)that allow mobile clients to access multi me-dia material anywhere and anyti me over a cellular ra-dio network[1,2].In M2DLS,multi media objects,ingeneral,can be composed of multiple media streamssuch as audio and video,whose retrieval must proceedso as to not only … 相似文献
139.
140.
Fernanda L. Cross Aixa D. Marchand Michael Medina Andrea Villafuerte Deborah Rivas‐Drake 《Psychology in the schools》2019,56(4):483-496
This study examined the direct association between parental educational expectations and adolescents’ academic self‐efficacy, as well as the moderating influence of parental academic socialization messages. Participants were 148 Latino parent–adolescent dyads with the majority of Mexican origin (80.4%). Most of the parent participants were mothers (85.8%). Adolescents were 13 (46%) or 14 (54%) years of age, and 53% identified as female. Adolescents reported their academic self‐efficacy and perceptions of their parents’ educational expectations; parents reported on their academic socialization messages of shame/pressure and effort regarding academics. The results suggest that, after accounting for parents’ level of education and immigrant status, parental educational expectations were positively associated with adolescent academic self‐efficacy. This association was stronger among adolescents whose parents reported transmitting fewer messages of shame/pressure and academic effort. These results point to the importance of nuances in the content and type of academic socialization messages within Latino families. 相似文献