全文获取类型
收费全文 | 25997篇 |
免费 | 453篇 |
国内免费 | 35篇 |
专业分类
教育 | 18798篇 |
科学研究 | 2228篇 |
各国文化 | 270篇 |
体育 | 2017篇 |
综合类 | 35篇 |
文化理论 | 223篇 |
信息传播 | 2914篇 |
出版年
2022年 | 151篇 |
2021年 | 263篇 |
2020年 | 419篇 |
2019年 | 591篇 |
2018年 | 827篇 |
2017年 | 910篇 |
2016年 | 838篇 |
2015年 | 516篇 |
2014年 | 690篇 |
2013年 | 5058篇 |
2012年 | 666篇 |
2011年 | 716篇 |
2010年 | 557篇 |
2009年 | 546篇 |
2008年 | 624篇 |
2007年 | 597篇 |
2006年 | 533篇 |
2005年 | 473篇 |
2004年 | 443篇 |
2003年 | 396篇 |
2002年 | 446篇 |
2001年 | 470篇 |
2000年 | 453篇 |
1999年 | 461篇 |
1998年 | 250篇 |
1997年 | 268篇 |
1996年 | 307篇 |
1995年 | 255篇 |
1994年 | 258篇 |
1993年 | 223篇 |
1992年 | 349篇 |
1991年 | 333篇 |
1990年 | 366篇 |
1989年 | 345篇 |
1988年 | 322篇 |
1987年 | 272篇 |
1986年 | 282篇 |
1985年 | 345篇 |
1984年 | 284篇 |
1983年 | 269篇 |
1982年 | 218篇 |
1981年 | 234篇 |
1980年 | 199篇 |
1979年 | 256篇 |
1978年 | 235篇 |
1977年 | 205篇 |
1976年 | 178篇 |
1975年 | 139篇 |
1974年 | 139篇 |
1973年 | 160篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
982.
983.
Fisher M Paolone V Rosene J Drury D Van Dyke A Moroney D 《Research quarterly for exercise and sport》1999,70(4):361-368
Five women and 5 men were studied to examine the effects of submaximal exercise on thermoregulatory and hemodynamic variables during recovery in two environments: (a) control (C), 22 degrees C, 33% rh; and (b) hot humid (H), 32 degrees C. The participants exercised on a cycle ergometer at 60% of peak oxygen consumption for 35 min prior to 90 min of seated recovery. Sessions were identical, except for environment. Variables evaluated (p < .05) were: core temperature (TR), mean skin temperature (Ts), sweat rate (SR), heart rate (HR), stroke index (SI), cardiac index (CI), forearm blood flow (FBF), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Men and women exhibited similar patterns of TR, Ts, and SR in both environments. Ts and SR (collapsed means for gender) were higher in the H than in the C. DBP was higher in men than in women throughout recovery in both environments. With combined means for gender, HR was higher in the H than in the C. CI, SI, FBF, and SBP were similar in both environments and returned to baseline within 15 min into recovery. These data suggest that heat dissipation during extended recovery was accomplished with similar contributions of cutaneous vasodilation and sweating in M and F. Furthermore, the moderate exercise level did not influence hemodynamics beyond 15 min of recovery in either environment. 相似文献
984.
Sallis JF Calfas KJ Nichols JF Sarkin JA Johnson MF Caparosa S Thompson S Alcaraz JE 《Research quarterly for exercise and sport》1999,70(1):1-10
Project GRAD (Graduate Ready for Activity Daily) evaluates a university course to promote physical activity. In a randomized study, 338 university seniors participated in either an intervention or control course for academic credit, and posttest data were collected on 321. The control course was knowledge-oriented. The intervention course taught behavior change skills in weekly lectures and peer-led labs. Physical activity was assessed with 7-Day Physical Activity Recall interviews. The intervention had no significant effects on men. Among women, the intervention increased total physical activity during leisure, strengthening exercises, and flexibility exercise. This university course had the intended effects of promoting healthful patterns of physical activity among women, but no effects were observed on men, who were more active than women at baseline. 相似文献
985.
986.
Collective efficacy is an important determinant of the motivation of individuals within groups, with increases in collective efficacy producing more effort in a task and greater persistence when faced with failure. To test hypotheses concerning the impact of collective efficacy on effort and persistence, participants (n = 22) were assigned to triads (consisting of the participant and two confederates) and performed three time trials on cycle ergometers. After trial 1, the participants were assigned to either a high or low collective efficacy condition, receiving appropriate bogus performance feedback. All groups received failure feedback after trial 2. Effort was assessed by performance time and maximum heart rate (HRmax) achieved during performance. A 2 (collective efficacy condition) x 3 (trials) analysis of variance with repeated measures on trials revealed significant interaction effects for both performance time and HRmax. Fisher's least significant difference post-hoc tests indicated that, following efficacy manipulation, groups low in collective efficacy significantly reduced both their performance time and HRmax, whereas groups high in collective efficacy maintained performance and HRmax. However, predictions concerning the impact of failure on persistence were not supported. Our results provide partial support for the role of collective efficacy in team sports. 相似文献
987.
The AIDS Library evolved out of consumer health activism in response to the need for the latest HIV information, materials, and technology. In 1998, staff implemented a microcomputer-based integrated automated library system with Web publishing capability to link catalogs, databases of Philadelphia regional services, online publications, and fact sheets. The Web site, , became "live" December 1, 1998. History leading to its development and future plans are presented. 相似文献
988.
Estabrook AD 《Medical reference services quarterly》1999,18(3):79-84
There is a dearth of core lists for the mental health librarian and materials must be selected from several sources. This list is described as "basic," but it does provide a core collection of books, journals and Web sites which can be used by mental health librarians to build or evaluate collections. "Classics" not contained in this list should also be included in library collections as well as a comprehensive handbook, Tasman's Psychiatry, to which mental health practitioners can refer for a quick answer to a question. Most importantly, the library collection should reflect the purposes and philosophy of the medical staff and institution it supports. 相似文献
989.
This study examines the perceived impacts of electronic government or e-government adoption on U.S. cities. This research conducted a survey of Texas and Florida city managers in the fall of 2005 to find out their opinions on the impact of e-government on their city government. The results indicated that e-government is having a positive impact on management, stakeholder involvement, needs and collaboration, and procurement in American cities. There are, however, concerns over spam or unsolicited e-mail and the ability of e-government to reduce the level of staffing. The results of this study imply that, according to city managers' perceptions, e-government adoption in American city governments is positively viewed as having an impact on their organizations and communities. 相似文献
990.
In the summer of 2004, it was revealed that the U.S. Census Bureau had provided tabulations in 2002 and 2003 on Arab Americans to the Department of Homeland Security that included detailed information on the number of people of Arab backgrounds living in selected ZIP codes. Although not a violation of law, the Census Bureau realized that this perceived breach of confidentiality would have a negative impact on public trust, and within a few months following the news of the Arab American tabulations it announced that it would no longer assist law enforcement and intelligence agencies with tabulations on ethnic groups and other sensitive populations. In spite of this damage control, we believe that the Bureau's tabulation of Arab Americans provides momentum to a process that adversely affects data quality by increasing both non-response and the cost of obtaining survey and census data. We argue that there are no “methodological fixes” that can repair the damage, and further that public relations campaigns and internal administrative changes are not optimal solutions because of the governing structure within which the Bureau currently operates. Ultimately, the best way to limit the damage already done is to effect a political solution. Toward this end we describe short- and long-term actions. In the long run, we recommend removing the Census Bureau from the Executive branch of government and re-structuring it under a permanent and non-political oversight panel similar to either the Federal Reserve Board or the Congressional Budget Office. Such a move would make a strong statement that the Bureau is non-partisan federal statistical agency. 相似文献