全文获取类型
收费全文 | 13591篇 |
免费 | 175篇 |
国内免费 | 124篇 |
专业分类
教育 | 9061篇 |
科学研究 | 1406篇 |
各国文化 | 117篇 |
体育 | 2099篇 |
综合类 | 19篇 |
文化理论 | 142篇 |
信息传播 | 1046篇 |
出版年
2022年 | 113篇 |
2021年 | 162篇 |
2020年 | 291篇 |
2019年 | 418篇 |
2018年 | 562篇 |
2017年 | 564篇 |
2016年 | 488篇 |
2015年 | 343篇 |
2014年 | 371篇 |
2013年 | 2327篇 |
2012年 | 355篇 |
2011年 | 311篇 |
2010年 | 268篇 |
2009年 | 285篇 |
2008年 | 262篇 |
2007年 | 243篇 |
2006年 | 266篇 |
2005年 | 218篇 |
2004年 | 420篇 |
2003年 | 401篇 |
2002年 | 369篇 |
2001年 | 434篇 |
2000年 | 261篇 |
1999年 | 183篇 |
1998年 | 131篇 |
1997年 | 115篇 |
1996年 | 124篇 |
1995年 | 131篇 |
1994年 | 127篇 |
1993年 | 93篇 |
1992年 | 159篇 |
1991年 | 132篇 |
1990年 | 150篇 |
1989年 | 170篇 |
1988年 | 128篇 |
1987年 | 140篇 |
1986年 | 127篇 |
1985年 | 140篇 |
1984年 | 127篇 |
1983年 | 128篇 |
1982年 | 103篇 |
1981年 | 87篇 |
1980年 | 93篇 |
1979年 | 141篇 |
1978年 | 94篇 |
1977年 | 76篇 |
1976年 | 97篇 |
1975年 | 72篇 |
1974年 | 79篇 |
1973年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
931.
Today's doctoral programs continue to prepare students for a traditional academic career path despite the inadequate supply of research-focused faculty positions. We advocate for a broader doctoral curriculum that prepares trainees for a wide range of science-related career paths. In support of this argument, we describe data from our survey of doctoral students in the basic biomedical sciences at University of California, San Francisco (UCSF). Midway through graduate training, UCSF students are already considering a broad range of career options, with one-third intending to pursue a non-research career path. To better support this branching career pipeline, we recommend that national standards for training and mentoring include emphasis on career planning and professional skills development to ensure the success of PhD-level scientists as they contribute to a broadly defined global scientific enterprise. 相似文献
932.
933.
Plaisant O Courtois R Toussaint PJ Mendelsohn GA John OP Delmas V Moxham BJ 《Anatomical sciences education》2011,4(6):305-310
Assessment of the personalities of medical students could enable medical educators to formulate strategies for the best development of academic and clinical competencies. In this article, we focus on the experience of students in the anatomy dissecting room. While there have been many attempts to evaluate the emotional responses of medical students to human cadaveric dissection, there has been no investigation into how different personality traits affect the responses. The main hypothesis tested was that there is a relationship between personality traits and attitudes toward the dissection room. For the present study, a group of French medical students (n = 403; mean age 21.3 ± 1.6; 65.3% female) completed a "Big Five" personality inventory and a questionnaire to assess their attitudes in regard to human dissection. The findings are consistent with our hypothesis, in that we found a relationship between reporting anxiety and four of the "Big Five" dimensions (all except openness). The rated level of anxiety was positively correlated with negative affectivity, more strongly at the beginning than at the end of the course. There were significant gender differences in attitudes toward dissection. The findings are discussed in relation to the possibility of preparing students for the dissecting room experience and also in relation to the students' understanding of mortality issues. 相似文献
934.
T. Le Sage A. Bindel P. P. Conway L. M. Justham S. E. Slawson A. A. West 《Sports Engineering》2011,14(1):1-14
The research outlined in this paper was conducted to allow real-time processing, transmission and presentation of data to
swimming coaches and subsequently their swimmers in a training environment, focused on providing information relevant to strokes
in free swimming. This was achieved using a wearable wireless sensor and embedded programming techniques, using accelerations
involved in the swimming stroke to provide relevant features for coaches. Current methods used do not offer real-time response
to coaches, which results in the lack of real-time feedback and significantly increased post-session analysis time. Filtering
and signal processing algorithms are described here, which allow real-time data analysis to be embedded within a wireless
sensor node. The system significantly reduces the time for processing acquired data and has delivered a novel monitoring device
suitable for operation within the harsh environment of the pool. 相似文献
935.
Pascual Marqués-Bruna 《Sports Engineering》2011,13(4):195-204
This study examined aerodynamic properties and boundary layer stability in five cambered airfoils operating at the low Reynolds
numbers encountered in motor racing. Numerical modelling was carried out in the flow regime characterised by Reynolds numbers
0.82–1.29 × 106. The design Reynolds number of 3 × 106 was used as a reference. Aerodynamics variables were computed using AeroFoil 2.2 software, which uses the vortex panel method
and integral boundary layer equations. Validation of AeroFoil 2.2 software showed very good agreement between calculated aerodynamic
coefficients and wind tunnel experimental data. Drag polars, lift/drag ratio, pitching moment coefficient, chordwise distributions
(surface velocity ratio, pressure coefficient and boundary layer thickness), stagnation point, and boundary layer transition
and separation were obtained at angles of attack from −4° to 12°. The NASA NLF(1)-0414F airfoil offers versatility for motor
racing with a wide low-drag bucket, low minimum profile drag, high lift/drag ratio, laminar flow up to 0.7 chord, rapid concave
pressure recovery, high resultant pressure coefficient and stall resistance at low Reynolds numbers. The findings have implications
for the design of race car wings. 相似文献
936.
A number of recent studies have measured the extent and timing of segment rotation during the golf swing. A promising technique,
instantaneous screw axis (ISA) theory, could provide a better expression of segment rotation. In Part 1 of this two-part study,
the objectives are to identify the ISA of the pelvis, shoulders and left arm during the downswing, compute segment angular
velocity relative to that segment’s ISA and verify that ISA theory is a valid tool to analyse segment rotation during the
golf swing. Results indicate that for all subjects, at least 71% of marker velocity is a result of rotation about their respective
ISA, when averaging results over the duration of the downswing, confirming that motion is primarily rotational. Furthermore,
ISA position and orientation of each segment approaches, on average, the expected gross axis of rotation, confirming that
motion about the ISA is representative of joint motion. 相似文献
937.
Michaud-Paquette Y Magee P Pearsall D Turcotte R 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(1):12-21
The purpose of this study was to identify joint angular kinematics that corresponds to shooting accuracy in the stationary ice hockey wrist shot. Twenty-four subjects participated in this study, each performing 10 successful shots on four shooting targets. An eight-camera infra-red motion capture system (240 Hz), along with passive reflective markers, was used to record motion of the joints, hockey stick, and puck throughout the performance of the wrist shot. A multiple regression analysis was carried out to examine whole-body kinematic variables with accuracy scores as the dependent variable. Significant accuracy predictors were identified in the lower limbs, torso and upper limbs. Interpretation of the kinematics suggests that characteristics such as a better stability of the base of support, momentum cancellation, proper trunk orientation and a more dynamic control of the lead arm throughout the wrist shot movement are presented as predictors for the accuracy outcome. These findings are substantial as they not only provide a framework for further analysis of motor control strategies using tools for accurate projection of objects, but more tangibly they may provide a comprehensive evidence-based guide to coaches and athletes for planned training to improve performance. 相似文献
938.
对足球运动员在长期训练过程中身体准备的综合体系进行了分析。长期的研究结果表明,足球运动训练可以被划分为4个方面:1)单纯性身体活动的使用,2)不同目标训练过程的交替使用,3)较小训练周期固定结构的保留并作为训练过程的基础,4)专门性推动能力的有序发展。这4个方面可以有效地解决足球运动员全面身体准备的问题。 相似文献
939.
Matthew P. Ciszek 《The Journal of Academic Librarianship》2011,37(5):430-436
This article explores the relationship between the perceived campus environment for gay, lesbian, bisexual, and transgender (GLBT) students at colleges and universities and how academic libraries have deployed GLBT-related resources on the Web. Recommendations are made for increasing GLBT-related materials and information in academic libraries. 相似文献
940.
A. A. Talalaev I. P. Tishenko V. P. Fralenko V. M. Khachumov 《Scientific and Technical Information Processing》2011,38(5):313-321
The paper summarizes the experience of developing the PS ANN image recognition software system based on artificial neural
networks (ANNs). The real abilities of neural networks to solve image recognition, data compression, and extrapolation problems
are demonstrated. The results of experimental studies on accelerating parallel task computations are presented. 相似文献