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1.
ABSTRACT

Interval exercise training is increasingly recommended to improve health and fitness; however, it is not known if cardiovascular risk is different from continuous exercise protocols. This systematic review with meta-analyses assessed the effect of a single bout of interval exercise on cardiovascular responses that indicate risk of cardiac fibrillation and infarction compared to continuous exercise. Electronic databases Medline, CINAHL, Embase, Scopus and Cochrane were searched. Key inclusion criteria were: (1) intervals of the same intensity and duration followed by a recovery period and (2) reporting at least one of blood pressure, heart rate variability, arterial stiffness or function. Cochrane Risk of Bias tool and GRADE approach were used. Meta-analyses found that systolic blood pressure responses to interval exercise did not differ from responses to continuous exercise immediately (MD 8 mmHg [95% CI ?32, 47], p = 0.71) or at 60 min following exercise (MD 0 mmHg [95% CI ?2, 1], p = 0.79). However, reductions in diastolic blood pressure and flow-mediated dilation with interval exercise were observed 10–15 min post-exercise. The available evidence indicates that interval exercise does not convey higher cardiovascular risk than continuous exercise. Further investigation is required to establish the safety of interval exercise for clinical populations.  相似文献   
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Of all the senses, that of taste is perhaps the hardest to define and quantify and elucidation of the underlying mechanisms is unrespondingly difficult. This article describes a conceptual model — at the molecular level — for the four basic taste modalities, using apparent specific volume as a fundamental parameter. It also considers possible practical applications.  相似文献   
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The propagation of elastic waves in a heterogeneous bar of variable cross-sectional area is investigated via use of the method of characteristics andthe Laplace transform technique. The Young's modulus and density are assumed to be representable as either power law or exponential distributions in the axial coordinate. The transform method is used to establish an infinite number of multi-parameter solutions in closed form for either a stress, velocity or displacement type boundary condition. The numerical characteristic computations show excellent agreement when compared to the transform solutions, and are then used to obtain additional solutions not attainable by the transform method. Detailed results and conclusions for a bar of ogival cross-section are given for a wide range of inhomogeneity.  相似文献   
5.

Purpose

Having been rated the world's leader in e-Government Readiness in 2002, 2004, and 2005, Taiwan sought to capitalize on its experience in e-Government implementation by launching, in 2007, a new Government-to-Citizen service entitled “e-Housekeeper”. The success of this service has since then become an important focus for practitioners.

Methodology

The reported research utilizes a psychological approach that is different from the classical models that dominate the existing literature, by examining how citizens’ adaptive–innovative cognitive styles and involvement jointly influence their loyalty intentions towards e-Housekeeper. The style/involvement model is tested by means of information from a sample of 206 Taiwan citizens.

Findings

While innovators initiated e-Housekeeper significantly earlier than others, their usage did not last for long. In contrast, more-involved citizens have shown higher loyalty intentions. More specifically, a combination of decision-making style and involvement significantly influences both when citizens try the service and whether they continue to use it: more-involved adaptors reported the strongest loyalty intentions.

Originality/value

Practical implications of the findings for the style/involvement model are suggested in the context of enhancing the strategic performance of e-Government services. The value of the style/involvement model is enhanced as a social scientific approach to the analysis of consumer innovation.  相似文献   
6.
Gordon Reikard   《Research Policy》2005,34(10):1476-1490
In the recent endogenous growth literature, the trend in output is stochastic, while investment in scientific knowledge is treated as analogous to a capital stock. This paper models both research and development (R&D) and disembodied technical advance using neo-classical equations, which specify the equilibrium stocks as a function of prices and output. The elasticity of R&D in the production function, estimated using factor shares, is time-varying and increasing. Returns to scale are increasing in all factors. The most important aspect of the model is that the equilibrium rate of technical advance is not cyclically invariant, but co-moves with output at business cycle frequencies. This allows the production function to behave as a stochastic trend. Growth accounting demonstrates that long-term variations in the rate of productivity growth have been associated mainly with low-frequency fluctuations in the rate of disembodied technical advance, with secondary effects from the stocks of R&D and physical capital. During the high productivity period 1948–1972, technical advance contributed 1.48 percentage points per year to output, with 0.98 accounted for by R&D. The productivity slowdown of the mid-1970s was accounted by a gradual decline in the effect of R&D, and a more abrupt collapse in disembodied technology. The subsequent productivity revival was associated with two accelerations in disembodied technical advance, the first beginning in the early 1980s, and the second in the mid-1990s. The production function is simulated in a small econometric model. Model simulations find that exogenous shocks to the inflation rate generate significant variations in growth by inducing fluctuations in disembodied technology.  相似文献   
7.
Animals given electroconvulsive shock (ECS) following active avoidance training were found to exhibit poor retention of the active avoidance response. However, this deficit was alleviated if the animals received an extinction trial for active avoidance prior to retention testing. That the trial was an extinction trial was demonstrated by the fact that exposure to the trial decremented the performance of animals not given ECS after learning. The implications of these findings for explanations of retrograde amnesia are discussed.  相似文献   
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Although most ACL injury prevention programmes encourage greater hip and knee flexion during landing, it remains unknown how this technique influences tibiofemoral joint forces. We examined whether a landing strategy utilising greater hip and knee flexion decreases tibiofemoral anterior shear and compression. Twelve healthy women (25.9 ± 3.5 years) performed a drop-jump task before and after a training session (10–15 min) that emphasised greater hip and knee flexion. Peak tibiofemoral anterior shear and compressive forces were calculated using an electromyography (EMG)-driven knee model that incorporated joint kinematics, EMG and participant-specific muscle volumes and patella tendon orientation measured using magnetic resonance imaging (MRI). Participants demonstrated a decrease in peak anterior tibial shear forces (11.1 ± 3.3 vs. 9.6 ± 2.7 N · kg?1; P = 0.008) and peak tibiofemoral compressive forces (68.4 ± 7.6 vs. 62.0 ± 5.5 N · kg?1; P = 0.015) post-training. The decreased peak anterior tibial shear was accompanied by a decrease in the quadriceps anterior shear force, while the decreased peak compressive force was accompanied by decreased ground reaction force and hamstring forces. Our data provide justification for injury prevention programmes that encourage greater hip and knee flexion during landing to reduce tibiofemoral joint loading.  相似文献   
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