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91.
Costas Chryssanthopoulos Christos Ziaras Tanja Oosthuyse Ioannis Lambropoulos Paradisis Giorgios P Elias Zacharogiannis 《Journal of sports sciences》2018,36(7):824-833
This study examined the effect of carbohydrate mouth rinsing on endurance running performance in women. Fifteen female recreational endurance runners, who used no oral contraceptives, ran two races of 1-h duration on an indoor track (216-m length) at 18:00 h after an 8-h fast with a 7-days interval between races, corresponding to the 3rd-10th day of each premenopausal runner’s menstrual cycle, or any day for the postmenopausal runners. In a double-blind random order, participants rinsed their mouth with 25 ml of either a 6.4% carbohydrate (RCHO) or a placebo solution (RP). No fluid was ingested during exercise. Serum 17β-Εstradiol (P = 0.59) and Progesterone (P = 0.35) did not differ between treatments. There was no difference in 1-hour running performance (RCHO: 10,621.88 ± 205.98 m vs. RP: 10,454.00 ± 206.64 m; t = 1.784, P = 0.096). Furthermore, the mean percentage effect (±99%CI) of RCHO relative to RP, 1.67% (?1.1% to 4.4%), and Cohen’s effect size (d = 0.21) support a trivial outcome of RCHO for total distance covered. In conclusion, carbohydrate mouth rinsing did not improve 60-min track running performance in female recreational runners competing in a low ovarian hormone condition, after an 8-h fast and when no fluid was ingested during exercise. 相似文献
92.
Kristina Andersson 《Cultural Studies of Science Education》2017,12(2):425-433
Marie Ståhl and Anita Hussénius have defined what discourses dominate national tests in chemistry for Grade 9 in Sweden by using feminist, critical didactic perspectives. This response seeks to expand the results in Ståhl and Hussénius’s article Chemistry inside an epistemological community box!—Discursive exclusions and inclusions in the Swedish national tests in chemistry, by using different facets of gender awareness. The first facet—Gender awareness in relations to the test designers’ own conceptions—highlighted how the gender order where women are subordinated men becomes visible in the national tests as a consequence of the test designers internalized conceptions. The second facet—Gender awareness in relation to chemistry—discussed the hierarchy between discourses within chemistry. The third facet—Gender awareness in relation to students—problematized chemistry in relation to the students’ identity formation. In summary, I suggest that the different discourses can open up new ways to interpret chemistry and perhaps dismantle the hegemonic chemistry discourse. 相似文献
93.
94.
Recently direct optimization of information retrieval (IR) measures has become a new trend in learning to rank. In this paper,
we propose a general framework for direct optimization of IR measures, which enjoys several theoretical advantages. The general
framework, which can be used to optimize most IR measures, addresses the task by approximating the IR measures and optimizing
the approximated surrogate functions. Theoretical analysis shows that a high approximation accuracy can be achieved by the
framework. We take average precision (AP) and normalized discounted cumulated gains (NDCG) as examples to demonstrate how
to realize the proposed framework. Experiments on benchmark datasets show that the algorithms deduced from our framework are
very effective when compared to existing methods. The empirical results also agree well with the theoretical results obtained
in the paper. 相似文献
95.
A novel floating foundation to support the NREL offshore 5 MW wind turbine was designed conceptually by combining the characteristics of barge and Spar. The main focus was structural design and hydrodynamic modelling. Based on this novel floating foundation, the hydrodynamic performance was investigated in the frequency domain and time domain by using the wave analysis software HydroD and DeepC from Det Norske Veritas. The frequency domain analysis was conducted to investigate the effects of the incident wave angle and water depth. The time-domain analysis was carried out to evaluate the response of the floating foundation under a selected operational condition. The hydrodynamic performances of this floating foundation with respect to time series and response spectra were also investigated in this study. 相似文献
96.
ZHANG Ji-gao 《浙江大学学报(A卷英文版)》2007,8(3):361-369
Particle pollution in air, also sometimes known as fine dust contamination, may cause electric contact failure. Recent research further proved that the fine particle is becoming a major disruption of the electronic connectors in signal transmission system. This paper specifies the connector contact in mobile phone application. To study the contact failure of mobile phone, a series of inspections and analytical research methods are introduced. Special features that cause the contact failure are summarized. Particle accumulation is the main problem; organic material such as lactates from sweat of the human body may act as adhesives to stick the separate particles together and make them adhere on the contact surface; chemical properties of dust cause serious local corrosion. The corrosion products may trap the particles and firmly attach on the contact surface; micro motion frequently occurs at the contact interface. Hard particle can be embedded into the surface, and soft particle could be squeezed and inserted into the contact; silicon compounds in dust play the most important role in forming high resistance regions that lead to failure; deposition of particles depends on the amount of materials, static electricity attracting force and gravity force applied on the particles. Current dust test can hardly reflect the serious contact failure. It is difficult to simulate the complexity of contact failure caused by particle contamination. Thus alternative ways of simulation experiment and improvement of contact reliability are proposed. 相似文献
97.
98.
Induction of diabetes by Streptozotocin in rats 总被引:1,自引:0,他引:1
A. Akbarzadeh D. Norouzian M. R. Mehrabi Sh. Jamshidi A. Farhangi A. Allah Verdi S. M. A. Mofidian B. Lame Rad 《Indian journal of clinical biochemistry : IJCB》2007,22(2):60-64
The objective of this study is to induce experimental diabetes mellitus by Streptozotocin in normal adult Wistar rats via
comparison of changes in body weight, consumption of food and water, volume of urine and levels of glucose, insulin and C-peptide
in serum, between normal and diabetic rats. Intra-venous injection of 60mg/kg dose of Streptozotocin in adult wistar rats,
makes pancreas swell and at last causes degeneration in Langerhans islet beta cells and induces experimental diabetes mellitus
in the 2–4 days. Induction of experimental diabetes mellitus is indeed the first step in the plan of purification of pancreatic
Langerhans islet cells of normal rats for transplanting under the testis subcutaneous of experimentally induced diabetic rats.
Streptozotocin induces one type of diabetes which is similar to diabetes mellitus with non-ketosis hyperglycemia in some animal
species. For induction of experimental diabetes in male adult rats weighted 250–300 grams (75–90 days), 60mg/kg of Streptozotocin
was injected intravenously. Three days after degeneration of beta cells, diabetes was induced in all animals. The diabetic
and normal animals were kept in the metabolic cages separately and their body weight, consumption of food and water, urine
volume, the levels of serum glucose, insulin and C-peptide quantities in all animals were measured and then these quantities
were compared. For a microscopic study of degeneration of Langerhans islet beta cells of diabetic rats, sampling from pancreas
tissue of diabetic and normal rats, staining and comparison between them, were done. Induction of diabetes with Streptozotocin
decreases Nicotinamide-adenine dinucleotide (NAD) in pancreas islet beta cells and causes histopathological effects in beta
cells which probably intermediates induction of diabetes. In this study, we used Streptozotocin for our experiments in induction
of experimental diabetes mellitus. After Induction of diabetes, consumption of food and water, volume of urine and glucose
increased in the diabetic animals in comparison with normal animals, but the weight of body and the volume of insulin and
C-peptide decreased in the diabetic animals. Sampling and staining of pancreas tissue of diabetic and normal rats showed that
the Langerhans islet beta cells of diabetic rats have been clearly degenerated. In three days, Streptozotocin makes pancreas
swell and at last causes degeneration in Langerhans islet beta cells and induces experimental diabetes. It also changes normal
metabolism in diabetic rats in comparison with normal rats. Consumption of water and food, volume of urine, serum glucose
increases in diabetic animals in comparison with normal rats but the levels of serum insulin, C-peptide and body weight decreases. 相似文献
99.
In this paper, we consider theories about processes of visual perception and perception-based knowledge representation (VPR)
in order to explain difficulties encountered in figural processing in junior high school geometry tasks. In order to analyze
such difficulties, we take advantage of the following perspectives of VPR: (1) Perceptual organization: Gestalt principles,
(2) recognition: bottom-up and top-down processing; and (3) representation of perception-based knowledge: verbal vs. pictorial
representation, mental images and hierarchical structure of images. Examples given in the paper were mostly taken from Gal's
study (2005) which aimed at identifying and analyzing Problematic Learning Situations (after Gal & Linchevski, 2000) in junior high school geometry classes. Gal's study (2005) suggests that while this theoretical perspective became part of teachers' pedagogic content knowledge, the teachers were
aware of their students' thinking processes and their ability to analyze and cope with their students’ difficulties in geometry
was improved. 相似文献
100.
Soumela Atmatzidou Stavros Demetriadis Panagiota Nika 《Journal of Science Education and Technology》2018,27(1):70-85
Educational robotics (ER) is an innovative learning tool that offers students opportunities to develop higher-order thinking skills. This study investigates the development of students’ metacognitive (MC) and problem-solving (PS) skills in the context of ER activities, implementing different modes of guidance in two student groups (11–12 years old, N1 = 30, and 15-16 years old, N2 = 22). The students of each age group were involved in an 18-h group-based activity after being randomly distributed in two conditions: “minimal” (with minimal MC and PS guidance) and “strong” (with strong MC and PS guidance). Evaluations were based on the Metacognitive Awareness Inventory measuring students’ metacognitive awareness and on a think-aloud protocol asking students to describe the process they would follow to solve a certain robot-programming task. The results suggest that (a) strong guidance in solving problems can have a positive impact on students’ MC and PS skills and (b) students reach eventually the same level of MC and PS skills development independently of their age and gender. 相似文献