全文获取类型
收费全文 | 745篇 |
免费 | 22篇 |
专业分类
教育 | 463篇 |
科学研究 | 73篇 |
各国文化 | 8篇 |
体育 | 132篇 |
综合类 | 2篇 |
文化理论 | 16篇 |
信息传播 | 73篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 24篇 |
2020年 | 30篇 |
2019年 | 42篇 |
2018年 | 61篇 |
2017年 | 58篇 |
2016年 | 51篇 |
2015年 | 26篇 |
2014年 | 32篇 |
2013年 | 126篇 |
2012年 | 37篇 |
2011年 | 27篇 |
2010年 | 26篇 |
2009年 | 18篇 |
2008年 | 32篇 |
2007年 | 20篇 |
2006年 | 16篇 |
2005年 | 21篇 |
2004年 | 17篇 |
2003年 | 9篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1962年 | 1篇 |
1935年 | 1篇 |
1903年 | 1篇 |
排序方式: 共有767条查询结果,搜索用时 15 毫秒
171.
Christian?Stummer Walter J?Gutjahr Michaela?Denk Harald?Riedmann Karl A?FroeschlEmail author 《知识管理研究与实践》2012,10(1):64-78
In the project ‘Competence-Driven Project Portfolio Analysis’ (CDPPA), an integrated system for supporting R&D project selection, staff assignment and activity scheduling with special consideration of the strategic development of competencies has been designed and implemented prototypically. The system has been field-tested at the Electronic Commerce Competence Center (EC3), a public–private partnership R&D enterprise. Experiences from this trial application are summarised and discussed, particularly concerning data collection and competence measurement, the benefits and limits of the chosen multi-criteria decision analysis approach, the evaluation of introduced changes to the decision-making processes, and the transparency of the formal planning model and its components. 相似文献
172.
Volianitis S Dawson EA Dalsgaard M Yoshiga C Clemmesen J Secher NH Olsen N Nielsen HB 《Journal of sports sciences》2012,30(2):149-153
Reduced hepatic lactate elimination initiates blood lactate accumulation during incremental exercise. In this study, we wished to determine whether renal lactate elimination contributes to the initiation of blood lactate accumulation. The renal arterial-to-venous (a-v) lactate difference was determined in nine men during sodium lactate infusion to enhance the evaluation (0.5 mol x L(-1) at 16 ± 1 mL x min(-1); mean ± s) both at rest and during cycling exercise (heart rate 139 ± 5 beats x min(-1)). The renal release of erythropoietin was used to detect kidney tissue ischaemia. At rest, the a-v O(2) (CaO(2)-CvO(2)) and lactate concentration differences were 0.8 ± 0.2 and 0.02 ± 0.02 mmol x L(-1), respectively. During exercise, arterial lactate and CaO(2)-CvO(2) increased to 7.1 ± 1.1 and 2.6 ± 0.8 mmol x L(-1), respectively (P < 0.05), indicating a -70% reduction of renal blood flow with no significant change in the renal venous erythropoietin concentration (0.8 ± 1.4 U x L(-1)). The a-v lactate concentration difference increased to 0.5 ± 0.8 mmol x L(-1), indicating similar lactate elimination as at rest. In conclusion, a -70% reduction in renal blood flow does not provoke critical renal ischaemia, and renal lactate elimination is maintained. Thus, kidney lactate elimination is unlikely to contribute to the initial blood lactate accumulation during progressive exercise. 相似文献
173.
174.
175.
176.
177.
Christian Denger Barbara Paech und Bernd Freimut 《Informatik - Forschung und Entwicklung》2005,20(1-2):11-23
Zusammenfassung Seit der Einführung von Use Cases hat deren Bedeutung zur Spezifikation von Anforderungen stetig zugenommen. Die Qualit?t
der Use Cases ist ein entscheidender Faktor für den Erfolg des Entwicklungsprozesses, da die meisten Entwicklungsschritte
auf den Use Cases aufbauen. Trotz der extremen Wichtigkeit der Qualit?t der Use Cases stellen die meisten use-case-basierten
Entwicklungsans?tze keine oder nur unzureichende integrierte qualit?tssichernde Ma?nahmen bereit (z.B. ad-hoc Empfehlungen,
Erstellungsrichtlinien, einige Checklisten zur Inspektion von Use Cases). Diese Techniken werden in den meisten F?llen unabh?ngig
voneinander eingesetzt, so dass bestimmte Fehlerklassen in den Use Cases durch mehrere Techniken, andere Fehlerklassen überhaupt
nicht adressiert werden. In diesem Artikel wird ein integrierter Ansatz vorgestellt, in dem Use Case Erstellungsrichtlinien,
Inspektionen und Simulation in systematischer Weise miteinander verknüpft werden. Der Ansatz basiert auf einer Fehlerklassifikation
für Use Cases, die als Grundlage dient, die verschiedenen Techniken auf bestimmte Fehlerarten zu fokussieren .
Since their introduction, use cases (UCs) have become increasingly important for the specification of software requirements. High quality UCs are a prerequisite for project success. Despite the high importance of their quality, UC driven approaches often lack systematic and integrated quality assurance techniques. Only ad-hoc recommendations, creation guidelines, and a few checklists for inspection are available in the literature. If at all, these techniques are developed and used separately, so that one class of defects is addressed by several techniques and other classes are not addressed at all. In this paper, we present an integrated approach that combines UC creation guidelines, UC inspections, and simulation in a systematic way. We base our combined approach on a defect classification for use cases. This classification enables the requirements engineer to focus the different techniques on different types of defects.
CR Subject Classification D2.1 相似文献
178.
Diese Arbeit stellt ein Modell und ein System zur Steuerung von Exoskeletten mit Hilfe von elektrischen
Signalen vor, die an den Muskeln des Benutzers gemessen werden. Anhand dieser Signale wird der eigene Drehmomentbeitrag
des Benutzer zur gewünschten Bewegung abgesch?tzt, und ein einstellbarer Faktor bestimmt das vom
Exoskelett hinzugefügte Drehmoment in Bezug auf den Beitrag des Benutzers. Die Signale werden durch
ein komplexes biomechanisches Modell ausgewertet. 相似文献
179.
Robert J. Noonan Danielle Christian Lynne M. Boddy Pedro F. Saint-Maurice Gregory J. Welk Paul R. Hibbing 《Journal of sports sciences》2019,37(16):1919-1925
This study used accelerometer and self-report measures of overall sedentary time (ST) and screen time behaviours to examine their respective associations with adiposity among UK youth. Participants (Year groups 5, 8, and 10; n=292, 148 girls) wore the SenseWear Armband Mini accelerometer for eight days and completed the Youth Activity Profile, an online report tool designed to estimate physical activity and ST.Stature, body mass and waist circumference were measured to classify adiposity outcomes (overweight/obese and central obesity). One-way between groups ANOVA and adjusted linear, logistic and multinomial logistic regression analyses were conducted. There was a significant main effect of age on total ST across the whole week (F(2, 289)=41.64, p≤0.001). ST increased monotonically across Year 5 (581.09±107.81 min·dˉ¹), 8 (671.96±112.59 min·dˉ¹) and 10 (725.80±115.20 min·dˉ¹), and all pairwise comparisons were significant at p≤0.001. A steep age-related gradient to mobile phone use was present (p≤0.001). ST was positively associated with adiposity outcomes independent of moderate-to-vigorous intensity physical activity (MVPA; p≤0.001). Engaging in >3 hours of video gaming daily was positively associated with central obesity (OR=2.12, p≤0.05) but not after adjustment for MVPA. Results further demonstrate the importance of reducing overall ST to maintain healthy weight status among UK youth. 相似文献
180.