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   14376篇
  免费   226篇
  国内免费   21篇
教育   10009篇
科学研究   1622篇
各国文化   145篇
体育   1263篇
综合类   6篇
文化理论   107篇
信息传播   1471篇
  2021年   160篇
  2020年   232篇
  2019年   318篇
  2018年   426篇
  2017年   403篇
  2016年   409篇
  2015年   261篇
  2014年   349篇
  2013年   2501篇
  2012年   316篇
  2011年   345篇
  2010年   301篇
  2009年   242篇
  2008年   291篇
  2007年   255篇
  2006年   254篇
  2005年   220篇
  2004年   238篇
  2003年   224篇
  2002年   192篇
  2001年   450篇
  2000年   300篇
  1999年   264篇
  1998年   123篇
  1997年   169篇
  1996年   140篇
  1995年   136篇
  1994年   154篇
  1993年   116篇
  1992年   195篇
  1991年   201篇
  1990年   195篇
  1989年   207篇
  1988年   176篇
  1987年   168篇
  1986年   172篇
  1985年   212篇
  1984年   174篇
  1983年   160篇
  1982年   138篇
  1981年   126篇
  1980年   124篇
  1979年   175篇
  1978年   140篇
  1977年   125篇
  1976年   93篇
  1975年   114篇
  1974年   102篇
  1973年   109篇
  1971年   98篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
Though there is a long tradition of band members quitting the group or taking a hiatus, the rock group as an organization to produce music continues to be both popular and economically viable. The research question addressed in this paper is whether or not it is a good idea to quit or take a hiatus from the group. We begin with a discussion of the framework for understanding why groups are formed and why they may be difficult to keep together. We then discuss differences between groups in the decade of the 1960s versus today. We argue that there is something unique about the output of the group even with the changes in the structure of contracts, compensation, and consumer focus on the artist that explain the resilience of the rock band as an organizational form within which to create music. We compare the charting success of bands that have members leave the group with the charting success of the members who left the group. We identified the groups in five representative years: 1965, 1975, 1985, 1995, and 2005. We then analyzed the entire Billboard Hot 100 charting careers of those groups and the artists who quit those groups. Our main finding is that when charting success is divided equally among members, going solo pays off—there is a clear economic rationale because solo acts have greater average charting success than the original bands they started in. The other ensuing side projects: duos, collaborations, and other groups are not as lucrative as the original bands. These findings are valid for members of charting groups from each of the 5 years examined. Despite the difficulties in keeping a rock band together, there are fewer band breakups today and remaining with the group generally results in a longer and more productive charting career. Thus, the rock group remains an important organization for producing contemporary music. However, there remains a compelling incentive to go solo. Superstars may benefit from solo projects, but for the average, non-superstar group member, in many circumstances it is better for the band to stay together if the income is divided equally.  相似文献   
133.
We conduct an analysis of 1835 pledges to 10 music production projects hosted on the largest Brazilian crowdfunding platform, namely the Catarse Web site, and we assess the relation between the fundraising accumulation period, the donor–entrepreneur distance and the propensity of donors to back projects. Our results suggest a significantly negative association between distance and the value of capital pledged to projects, which is consistent with the notion that the entrepreneur’s network of close contacts might play a central role in funding. Furthermore, our results contradict the idea that crowdfunding reduces the inhibiting effect of donor–entrepreneur distance. In addition, the results show that a long project exposure is associated with higher values of pledges. These results suggest practical implications for the study of crowdfunding as a financing platform. This study contributes to the literature on the use of crowdfunding as an alternative funding source in a major emerging market.  相似文献   
134.
Knowing what the Communication job market is can be helpful and informative when planning how to build a program of study or research. On the other side, those who are looking for a job or are preparing for future job hunting also need knowledge about the current job market to help make decisions and predictions. To facilitate these processes, this article surveys the entirety of job postings posted on NCA’s CRTNET service and Spectra publication over the course of 2013 and 2014. The analyses provide an in-depth look at what kind of positions are being offered, which have tenure-track options, what degrees are required, if and what research methodological experience is needed, what kind of institution is offering the position, whether grant and/or teaching experience is desired, and what kinds of topical specializations are sought after.  相似文献   
135.
Educational objectives focus practice and dictate what happens in US classrooms. Currently, instructional objectives are privileged in K–12 schools over other forms of objectives, thereby marginalizing the implementation of some educational perspectives. We argue that objectives should be expanded to attend to the student experience, promoting a variety of practices to utilize in classroom operations. In so doing, we suggest an addition to the network of objectives: experience-based objectives. We review the history of objectives before presenting experience-based objectives as embodying 5 major shifts in thinking, and as actualized through four criteria.  相似文献   
136.
Arterial spin labelling (ASL) provides a potential method to non-invasively determine muscle blood flow and examine the impact of interventions such as supplementation and training. However, it's a method with intrinsically low signal, leading to limitations in accuracy and temporal resolution. To examine these limitations, the current study measured perfusion via ASL on three occasions in the rectus femoris of 10 healthy adults, during light and moderate exercise, over three different exercise durations. For data sampled over 9 min, light intensity exercise gave an average perfusion of 35.0 ± 5.1 ml/min.100g?1 with a coefficient of variation (COV) of 16% and single intraclass correlation coefficient (ICC) of 0.67. For the moderate bout, perfusion was 51.3 ± 5.6 ml/min.100g?1 (COV 10%, ICC 0.82). When the same data were analyzed over 5 min 24 s, perfusion was 37.8 ± 11.13 (COV 30%, ICC 0.13) during light and 49.5 ± 8.8 ml/min.100g?1 (COV 18%, ICC 0.52) during moderate exercise. When sampling was reduced to 1 min 48 s, perfusion was 41.2 ± 13.7 (COV 33%, ICC 0.26) during light and 49.5 ± 13.6 ml/min.100g?1 (COV 28%, ICC 0.04) during moderate exercise. For 9 min a significant perfusion difference was found between the exercise intensities; however, this was not the case for sampling over 5 min 24 s or 1 min 48 s. Such findings illustrate the potential of ASL to non-invasively monitor muscle perfusion under steady-state conditions, but highlight that extended exercise protocols are necessary in order to generate date of sufficient reliability to be able to discriminate intervention dependent perfusion differences.  相似文献   
137.
It is believed that sport massage after intensive exercise might improve power and perceptual recovery in athletes. However, few studies have been done in this area. This study aimed to examine the effect of massage on the performance of bodybuilders. Thirty experienced male bodybuilders were randomly assigned to either a massage group (n = 15) or a control group (n = 15). Both groups performed five repetition sets at 75–77% of 1RM of knee extensor and flexor muscle groups. The massage group then received a 30-min massage after the exercise protocol while the control group maintained their normal passive recovery. Criteria under investigation included: plasma creatine kinase (CK) level, agility test, vertical jump test, isometric torque test, and perception of soreness. All variables were measured over 6 time periods: baseline, immediately after the DOMS inducing protocol, right after the massage, and 24, 48, and 72 h after the massage. Both groups showed significant (P < .001) decreases in jumping, agility performance, and isometric torque, but significant (P < .001) increases in CK and muscle soreness levels. The massage group in general demonstrated a better recovery rate. As such, a post-exercise massage session can improve the exercise performance and recovery rate in male bodybuilders after intensive exercise.  相似文献   
138.
Artificial surfaces are now an established alternative to grass (natural) surfaces in rugby union. Little is known, however, about their potential to reduce injury. This study characterises the spinal kinematics of rugby union hookers during scrummaging on third-generation synthetic (3G) and natural pitches. The spine was sectioned into five segments, with inertial sensors providing three-dimensional kinematic data sampled at 40 Hz/sensor. Twenty-two adult, male community club and university-level hookers were recruited. An equal number were analysed whilst scrummaging on natural or synthetic turf. Players scrummaging on synthetic turf demonstrated less angular velocity in the lower thoracic spine for right and left lateral bending and right rotation. The general reduction in the range of motion and velocities, extrapolated over a prolonged playing career, may mean that the synthetic turf could result in fewer degenerative injuries. It should be noted, however, that this conclusion considers only the scrummaging scenario.  相似文献   
139.
Heavy training is associated with increased respiratory infection risk and antimicrobial proteins are important in defence against oral and respiratory tract infections. We examined the effect of 14 weeks of vitamin D3 supplementation (5000 IU/day) on the resting plasma cathelicidin concentration and the salivary secretion rates of secretory immunoglobulin A (SIgA), cathelicidin, lactoferrin and lysozyme in athletes during a winter training period. Blood and saliva were obtained at the start of the study from 39 healthy men who were randomly allocated to vitamin D3 supplement or placebo. Blood samples were also collected at the end of the study; saliva samples were collected after 7 and 14 weeks. Plasma total 25(OH)D concentration increased by 130% in the vitamin D3 group and decreased by 43% in the placebo group (both = 0.001). The percentage change of plasma cathelicidin concentration in the vitamin D3 group was higher than in the placebo group (= 0.025). Only in the vitamin D3 group, the saliva SIgA and cathelicidin secretion rates increased over time (both = 0.03). A daily 5000 IU vitamin D3 supplement has a beneficial effect in up-regulating the expression of SIgA and cathelicidin in athletes during a winter training period, which could improve resistance to respiratory infections.  相似文献   
140.
The relationships between team performance indicators and match outcome have been examined in many team sports, however are limited in Australian Rules football. Using data from the 2013 and 2014 Australian Football League (AFL) regular seasons, this study assessed the ability of commonly reported discrete team performance indicators presented in their relative form (standardised against their opposition for a given match) to explain match outcome (Win/Loss). Logistic regression and decision tree (chi-squared automatic interaction detection (CHAID)) analyses both revealed relative differences between opposing teams for “kicks” and “goal conversion” as the most influential in explaining match outcome, with two models achieving 88.3% and 89.8% classification accuracies, respectively. Models incorporating a smaller performance indicator set displayed a slightly reduced ability to explain match outcome (81.0% and 81.5% for logistic regression and CHAID, respectively). However, both were fit to 2014 data with reduced error in comparison to the full models. Despite performance similarities across the two analysis approaches, the CHAID model revealed multiple winning performance indicator profiles, thereby increasing its comparative feasibility for use in the field. Coaches and analysts may find these results useful in informing strategy and game plan development in Australian Rules football, with the development of team-specific models recommended in future.  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