全文获取类型
| 收费全文 | 3063篇 |
| 免费 | 58篇 |
| 国内免费 | 2篇 |
专业分类
| 教育 | 2339篇 |
| 科学研究 | 157篇 |
| 各国文化 | 35篇 |
| 体育 | 289篇 |
| 文化理论 | 49篇 |
| 信息传播 | 254篇 |
出版年
| 2023年 | 36篇 |
| 2022年 | 55篇 |
| 2021年 | 59篇 |
| 2020年 | 113篇 |
| 2019年 | 189篇 |
| 2018年 | 249篇 |
| 2017年 | 220篇 |
| 2016年 | 199篇 |
| 2015年 | 151篇 |
| 2014年 | 157篇 |
| 2013年 | 646篇 |
| 2012年 | 128篇 |
| 2011年 | 101篇 |
| 2010年 | 95篇 |
| 2009年 | 60篇 |
| 2008年 | 80篇 |
| 2007年 | 68篇 |
| 2006年 | 40篇 |
| 2005年 | 42篇 |
| 2004年 | 51篇 |
| 2003年 | 41篇 |
| 2002年 | 39篇 |
| 2001年 | 25篇 |
| 2000年 | 33篇 |
| 1999年 | 18篇 |
| 1998年 | 21篇 |
| 1997年 | 11篇 |
| 1996年 | 25篇 |
| 1995年 | 17篇 |
| 1994年 | 17篇 |
| 1993年 | 11篇 |
| 1992年 | 9篇 |
| 1991年 | 13篇 |
| 1990年 | 13篇 |
| 1989年 | 12篇 |
| 1988年 | 10篇 |
| 1987年 | 5篇 |
| 1986年 | 8篇 |
| 1985年 | 6篇 |
| 1980年 | 6篇 |
| 1979年 | 3篇 |
| 1978年 | 2篇 |
| 1977年 | 2篇 |
| 1976年 | 6篇 |
| 1975年 | 2篇 |
| 1974年 | 3篇 |
| 1973年 | 2篇 |
| 1972年 | 2篇 |
| 1970年 | 2篇 |
| 1967年 | 3篇 |
排序方式： 共有3123条查询结果，搜索用时 15 毫秒
121.
122.
Alexandra LaLonde Maria F. Romero-Creel Mario A. Saucedo-Espinosa Blanca H. Lapizco-Encinas 《Biomicrofluidics》2015,9(6)
Isolation and enrichment of low-abundant particles are essential steps in many bio-analytical and clinical applications. In this work, the capability of an insulator-based dielectrophoresis (iDEP) device for the detection and stable capture of low abundant polystyrene particles and yeast cells was evaluated. Binary and tertiary mixtures of particles and cells were tested, where the low-abundant particles had concentration ratios on the order of 1:10 000 000 compared to the other particles present in the mixture. The results demonstrated successful and stable capture and enrichment of rare particles and cells (trapping efficiencies over 99%), where particles remained trapped in a stable manner for up to 4 min. A device with four reservoirs was employed for the separation and enrichment of rare particles, where the particles of interest were first selectively concentrated and then effectively directed to a side port for future collection and analysis. The present study demonstrates that simple iDEP devices have appropriate screening capacity and can be used for handling samples containing rare particles; achieving both enrichment and isolation of low-abundant particles and cells. 相似文献
123.
Miguel-Ángel Gómez Otavio Battaglia Alberto Lorenzo Jorge Lorenzo Sergio Jiménez Jaime Sampaio 《Journal of sports sciences》2015,33(17):1844-1852
Ball screens are one of the most frequently used tactical behaviour in elite basketball games. The aim of the present study was to identify their predictors of success related to time, space, players, and tasks performed. The sample was composed of 818 ball screens corresponding to 20 close games (mean differences in score of 3.1 ± 0.8 points) randomly selected from the playoff games of the Spanish Basketball League (2008–2011). Classification tree analysis (CHAID) was used to analyse which variable or combination of variables, better predicts effectiveness during ball screens. The main results allowed identifying interactions with dribbler actions after the screen and the orientation of the screen on the ball. The results showed no interaction with game quarter and quarter minute temporal-related variables in both analyses. The present findings allow improving coaches’ strategic plans that involve selecting the most appropriate offensive approach when performing ball screens. 相似文献
124.
Irene R. Faber Maria W. G. Nijhuis-Van Der Sanden Marije T. Elferink-Gemser Frits G. J. Oosterveld 《Journal of sports sciences》2015,33(11):1149-1158
A motor skills assessment could be helpful in talent development by estimating essential perceptuo-motor skills of young players, which are considered requisite to develop excellent technical and tactical qualities. The Netherlands Table Tennis Association uses a motor skills assessment in their talent development programme consisting of eight items measuring perceptuo-motor skills specific to table tennis under varying conditions. This study aimed to investigate this assessment regarding its reproducibility, internal consistency, underlying dimensions and concurrent validity in 113 young table tennis players (6–10 years). Intraclass correlation coefficients of six test items met the criteria of 0.7 with coefficients of variation between 3% and 8%. Cronbach’s alpha valued 0.853 for internal consistency. The principal components analysis distinguished two conceptually meaningful factors: “ball control” and “gross motor function.” Concurrent validity analyses demonstrated moderate associations between the motor skills assessment’s results and national ranking; boys r = ?0.53 (P < 0.001) and girls r = ?0.45 (P = 0.015). In conclusion, this evaluation demonstrated six test items with acceptable reproducibility, good internal consistency and good prospects for validity. Two test items need revision to upgrade reproducibility. Since the motor skills assessment seems to be a reproducible, objective part of a talent development programme, more longitudinal studies are required to investigate its predictive validity. 相似文献
125.
Danuta Ro?? Przemys?aw Adamczyk Joanna Boinska Robert Szafkowski Irena Ponikowska Katarzyna Stankowska Barbara Góralczyk Barbara Ruszkowska-Ciastek 《Journal of Zhejiang University. Science. B》2015,16(5):404-411
Objective
The aim of this study was to evaluate the concentrations of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and the degree of homeostasis model assessment-insulin resistance (HOMA-IR) in patients with morbid obesity exposed to a three-week low-calorie diet and balneotherapy.Methods
The study included 33 patients (25 females and 8 males; mean age 46 years) with body mass index (BMI) values of >40 kg/m2. Evaluations of CRP, IL-6, TNF-α, lipid profile, HOMA-IR, and fasting glucose were carried out before (baseline data) and three weeks after the treatment. The control group consisted of 20 healthy volunteers (15 females and 5 males) with a mean age of 39 years and BMI values of ≤24.9 kg/m2.Results
In the blood of patients with morbid obesity we found significantly elevated levels of CRP, TNF-α, triglycerides, HOMA-IR and fasting glucose, but a decreased level of high density lipoprotein (HDL)-cholesterol, compared with the healthy individuals. The treatment resulted in about a 9.4% reduction in body weight from 122.5 to 111.0 kg and a significant decrease in the concentration of CRP, but no change in TNF-α or IL-6. HOMA-IR was significantly reduced.Conclusion
The decrease in CRP level without changes in TNF-α or IL-6 concentrations after the low-calorie diet and balneological treatment, suggests that an essential amount of adipose tissue must be removed before proper adipocyte function is restored. The decrease in HOMA-IR indicates an improvement in insulin sensitivity, which is beneficial in obese patients.126.
Maria C. Porcal-Gonzalo 《Journal of Map & Geography Libraries》2015,11(3):289-329
In recent years, there has been a growing recognition of the fact that the proper management of information has to include concern for its preservation and future re-use. This ambition is particularly significant for geospatial data. The primary aim of this article is to define the European and Spanish frameworks for the preservation and reutilization of geographical information, with the ultimate goal of proposing an articulated, lifecycle-based data management model. With this, the intent is to shed some light on a complex, difficult and ever-evolving subject.The article is divided into two main parts. The first part begins with a conceptual justification for geospatial data management and continues by synthesizing the current normative and technological framework for the preservation and reutilization of geographical information. Within this context, the implementation of Spatial Data Infrastructures (SDI) in Spain is evaluated. The second part begins with a case study from Spain that aims to identify different agents and flows that influence the lifecycle of geographical data, as well as the strengths and weaknesses found in each stage of the process under examination. Finally, the foregoing ideas are used in order to propose a SDI-related system for the management of geographical information. 相似文献
127.
Leonardo Madariaga Miguel Nussbaum Faustino Marañón Cristóbal Alarcón María Alicia Naranjo 《Government Information Quarterly》2019,36(2):179-195
People still use documents in many everyday government processes. From tax payments to passport requests, citizens have to interact with low-interactivity information artifacts such as reports, maps and datasets, among many others. Despite efforts to improve information delivery in the public sector, effective information usage remains a critical topic of action and research. The user experience of government documents has rarely been assessed, despite them being regularly published and frequently used. Considering this, the two following research questions arise: 1) How can government documents be classified (or grouped) in terms of user experience? 2) How can the user experience of government documents be monitored over time in order to inform design decisions? Working with a public agency in Chile, we develop and test a classification and monitoring framework based on two online surveys (N?=?338 and N?=?298). We then propose a framework for understanding user experience of government documents in these three dimensions: interaction goal, volume of information and ease of understanding. Using a graphical representation to classify user experience provides greater visibility of the current status of information produced by a public organization. Furthermore, by monitoring the user experience of a government document at different times, organizations can understand the effect of their design decisions and improve their service quality by implementing user-centered processes. 相似文献
128.
Méndez A Pérez C Montañéz JC Martínez G Aguilar CN 《Journal of Zhejiang University. Science. B》2011,12(12):961-968
The combined effects of pH and temperature on red pigment production and fungal morphology were evaluated in a submerged culture
of Penicillium purpurogenum GH2, using Czapek-Dox media with d-xylose as a carbon source. An experimental design with a factorial fix was used: three pH values (5, 7, and 9) and two temperature
levels (24 and 34 °C) were evaluated. The highest production of red pigment (2.46 g/L) was reached with a pH value of 5 and
a temperature of 24 °C. Biomass and red pigment production were not directly associated. This study demonstrates that P. purpurogenum GH2 produces a pigment of potential interest to the food industry. It also shows the feasibility of producing and obtaining
natural water-soluble pigments for potential use in food industries. A strong combined effect (p<0.05) of pH and temperature was associated with maximal red pigment production (2.46 g/L). 相似文献
129.
Ruszkowska B Gadomska G Bielis L Gruszka M Góralczyk B Rość D Odrowąż-Sypniewska G 《Journal of Zhejiang University. Science. B》2011,12(1):12-17
Objective
The influence of hormone replacement therapy (HRT) on hemostasis processes depends on the type of hormone, the combination of doses, the time of taking HRT, and the route of administration (oral, transdermal, implanted). The aim of the current study was to assess some parameters of coagulation, especially tissue factor pathway inhibitor (TFPI) and tissue factor (TF) in postmenopausal women using oral or transdermal HRT. 相似文献130.