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191.
本文初步对保山市反季节蔬菜进行分析,纵向从蔬菜种子的来源、蔬菜的栽培、蔬菜的收集销售、贮藏和运输这一商品链出发,逐级分析菜农、蔬菜收集人、菜老板的收益分析,从而在整体上揭示菜农在这条商品链上的收益地位;横向同种植其他经济作物,如香烟和甘蔗的收益作对比分析。说明了西部民族山区的广大农户主要收入来源于种植业的现实,农户如何选择种植的经济作物对提高收入有直接的影响,决定农户种植收益除了市场的因素以外各级政府的行政行为则也起到一定的作用。 相似文献
192.
Using Neural Network to Predict the Interfacial Friction and Flow Stress of Materialsvia Ring Compre
Xu Weiliang 《东南大学学报》1996,(1)
UsingNeuralNetworktoPredicttheInterfacialFrictionandFlowStressofMaterialsviaRingCompressionXuWeiliang(徐卫良)(DepartmentofMecha... 相似文献
193.
“鲍勃!鲍勃!”我身旁的女人大声命令着,“告诉她你去年为什么不愿跟那个女人结婚!”桌子对面的鲍勃顺从地粗着嗓子回答:“哦,她呀!那真是糟透了!她对我说,要是想跟她结婚的话,我就再也不能去跳舞了!我就告诉她,‘噢,我想我做不到。’” 相似文献
194.
Individual, family, and neighborhood factors distinguish resilient from non-resilient maltreated children: a cumulative stressors model 总被引:2,自引:0,他引:2
OBJECTIVE: Children who are physically maltreated are at risk of a range of adverse outcomes in childhood and adulthood, but some children who are maltreated manage to function well despite their history of adversity. Which individual, family, and neighborhood characteristics distinguish resilient from non-resilient maltreated children? Do children's individual strengths promote resilience even when children are exposed to multiple family and neighborhood stressors (cumulative stressors model)? METHODS: Data were from the Environmental Risk Longitudinal Study which describes a nationally representative sample of 1,116 twin pairs and their families. Families were home-visited when the twins were 5 and 7 years old, and teachers provided information about children's behavior at school. Interviewers rated the likelihood that children had been maltreated based on mothers' reports of harm to the child and child welfare involvement with the family. RESULTS: Resilient children were those who engaged in normative levels of antisocial behavior despite having been maltreated. Boys (but not girls) who had above-average intelligence and whose parents had relatively few symptoms of antisocial personality were more likely to be resilient versus non-resilient to maltreatment. Children whose parents had substance use problems and who lived in relatively high crime neighborhoods that were low on social cohesion and informal social control were less likely to be resilient versus non-resilient to maltreatment. Consistent with a cumulative stressors model of children's adaptation, individual strengths distinguished resilient from non-resilient children under conditions of low, but not high, family and neighborhood stress. CONCLUSION: These findings suggest that for children residing in multi-problem families, personal resources may not be sufficient to promote their adaptive functioning. 相似文献
195.
OBJECTIVE: Children's Advocacy Centers (CACs) aim to improve child forensic interviewing following allegations of child abuse by coordinating multiple investigations, providing child-friendly interviewing locations, and limiting redundant interviewing. This analysis presents one of the first rigorous evaluations of CACs' implementation of these methods. METHODS: This analysis is part of a quasi-experimental study, the Multi-Site Evaluation of Children's Advocacy Centers, which evaluated four CACs relative to within-state non-CAC comparison communities. Case abstractors collected data on investigation methods in 1,069 child sexual abuse cases with forensic interviews by reviewing case records from multiple agencies. RESULTS: CAC cases were more likely than comparison cases to feature police involvement in CPS cases (41% vs. 15%), multidisciplinary team (MDT) interviews (28% vs. 6%), case reviews (56% vs. 7%), joint police/child protective services (CPS) investigations (81% vs. 52%) and video/audiotaping of interviews (52% vs. 17%, all these comparisons p<.001). CACs varied in which coordination methods they used, and some comparison communities also used certain coordination methods more than the CAC with which they were paired. Eighty-five percent of CAC interviews took place in child-friendly CAC facilities, while notable proportions of comparison interviews took place at CPS offices (22%), police facilities (18%), home (16%), or school (19%). Ninety-five percent of children had no more than two forensic interviews, and CAC and comparison differences on number of interviews were mostly non-significant. CONCLUSIONS: Relative to the comparison communities, these CACs appear to have increased coordination on investigations and child forensic interviewing. The CAC setting was the location for the vast majority of CAC child interviews, while comparison communities often used settings that many consider undesirable. CACs showed no advantage on reducing the number of forensic interviews, which was consistently small across the sample. 相似文献
196.
Puolakanaho A Ahonen T Aro M Eklund K Leppänen PH Poikkeus AM Tolvanen A Torppa M Lyytinen H 《Journal of learning disabilities》2008,41(4):353-370
The authors examined second grade reading accuracy and fluency and their associations via letter knowledge to phonological and language predictors assessed at 3.5, 4.5, and 5.5 years in children in the Jyv?skyl? Longitudinal Study of Dyslexia. Structural equation modeling showed that a developmentally highly stable factor (early phonological and language processing [EPLP]) behind key dyslexia predictors (i.e., phonological awareness, short-term memory, rapid naming, vocabulary, and pseudoword repetition) could already be identified at 3.5 years. EPLP was significantly associated with reading and spelling accuracy and by age with letter knowledge. However, EPLP had only a minor link with reading fluency, which was additionally explained by early letter knowledge. The results show that reading accuracy is well predicted by early phonological and language skills. Variation in fluent reading skills is not well explained by early skills, suggesting factors other than phonological core skills. Future research is suggested to explore the factors behind the development of fast and accurate decoding skills. 相似文献
197.
198.
Terrall M 《Isis; an international review devoted to the history of science and its cultural influences》2006,97(4):683-699
In eighteenth-century France, geodesy (the measure of the earth's shape) became an arena where mathematics and narrative intersected productively. Mathematics played a crucial role not only in the measurements and analysis necessary to geodesy but also in the narrative accounts that presented the results of elaborate and expensive expeditions to the reading public. When they returned to France to write these accounts after their travels, mathematician-observers developed a variety of ways to display numbers and mathematical arguments and techniques. The numbers, equations, and diagrams they produced could not be separated from the story of their acquisition. Reading these accounts for the interplay of these two aspects--the mathematical and the narrative--shows how travelers articulated the intellectual and physical difficulties of their work to enhance the value of their results for specialist and lay readers alike. 相似文献
199.
200.
The aim of this study was to examine the effects of muscle-tendon length on joint moment and power during maximal sprint starts. Nine male sprinters performed maximal sprint starts from the blocks that were adjusted either to 40 degrees or 65 degrees to the horizontal. Ground reaction forces were recorded at 833 Hz using a force platform and kinematic data were recorded at 200 Hz with a film camera. Joint moments and powers were analysed using kinematic and kinetic data. Muscle - tendon lengths of the medial gastrocnemius, soleus, vastus medialis, rectus femoris and biceps femoris were calculated from the set position to the end of the first single leg contact. The results indicated that block velocity (the horizontal velocity of centre of mass at the end of the block phase) was greater (P < 0.01) in the 40 degrees than in the 65 degrees block angle condition (3.39 +/- 0.23 vs. 3.30 +/- 0.21 m . s(-1)). Similarly, the initial lengths of the gastrocnemius and soleus of the front leg in the block at the beginning of force production until half way through the block phase were longer (P < 0.001) in the 40 degrees than in the 65 degrees block angle condition. The initial length and the length in the middle of the block phase were also longer in the 40 degrees than in the 65 degrees block angle condition both for both the gastrocnemius (P < 0.01) and soleus (P < 0.01-0.05) of the rear leg. In contrast, the initial lengths of the rectus femoris and vastus medialis of the front leg were longer (P < 0.05) in the 65 degrees than in the 40 degrees block angle condition. All differences gradually disappeared during the later block phase. The peak ankle joint moment (P < 0.01) and power (P < 0.05) during the block phase were greater in the 40 degrees than in the 65 degrees block angle condition for the rear leg. The peak ankle joint moment during the block phase was greater (P < 0.05) in the 40 degrees block angle for the front leg, whereas the peak knee joint moment of the rear leg was greater (P < 0.01) in the 65 degrees block angle condition. The results suggest that the longer initial muscle-tendon lengths of the gastrocnemius and soleus in the block phase at the beginning of force production contribute to the greater peak ankle joint moment and power and consequently the greater block velocity during the sprint start. 相似文献