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991.
992.
Differential Item Functioning (DIF) is traditionally used to identify different item performance patterns between intact groups, most commonly involving race or sex comparisons. This study advocates expanding the utility of DIF as a step in construct validation. Rather than grouping examinees based on cultural differences, the reference and focal groups are chosen from two extremes along a distinct cognitive dimension that is hypothesized to supplement the dominant latent trait being measured. Specifically, this study investigates DIF between proficient and non-proficient fourth- and seventh-grade writers on open-ended mathematics test items that require students to communicate about mathematics. It is suggested that the occurrence of DIF in this situation actually enhances, rather than detracts from, the construct validity of the test because, according to the National Council of Teachers of Mathematics (NCTM), mathematical communication is an important component of mathematical ability, the dominant construct being assessed. However, the presence of DIF influences the validity of inferences that can be made from test scores and suggests that two scores should be reported, one for general mathematical ability and one for mathematical communication. The fact that currently only one test score is reported, a simple composite of scores on multiple-choice and open-ended items, may lead to incorrect decisions being made about examinees. 相似文献
993.
Chayna J. Davis Valerie S. Knopik Richard K. Olson Sally J. Wadsworth John C. DeFries 《Annals of dyslexia》2001,51(1):231-247
The present study assesses the genetic and environmental etiologies of reading, rapid naming (RN), and their covariation by
fitting multivariate structural equation models to data from 587 twin pairs in which at least one member of the pair exhibited
reading difficulties (low-range) and from 360 control (normal-range) twin pairs who were tested in the Colorado Learning Disabilities
Research Center. Results from a bivariate phenotypic analysis with two hypothesized latent factors, READ and RN, indicated
that the correlation between reading and rapid naming performance for the low-range sample was significantly higher than that
of the normal-range sample. When this model was partitioned to include estimates of genetic, shared environmental, and nonshared
environmental influences, resulting heritability estimates did not differ significantly for the low-range and normal-range
samples for either READ or RN. However, similar to the phenotypic correlation, the genetic correlation between the READ and
RN latent factors could not be equated for the two groups. Thus, the etiology of the relationship between reading performance
and rapid naming may differ for children with reading difficulties and normally-achieving readers. Moreover, these results
support previous findings that the best predictors of reading skills may differ for samples of children with normal reading
levels and those with reading difficulties. 相似文献
994.
Goldin-Meadow S 《Child development》2000,71(1):231-239
Gesture has privileged access to information that children know but do not say. As such, it can serve as an additional window to the mind of the developing child, one that researchers are only beginning to acknowledge. Gesture might, however, do more than merely reflect understanding-it may be involved in the process of cognitive change itself. This question will guide research on gesture as we enter the new millennium. Gesture might contribute to change through two mechanisms which are not mutually exclusive: (1) indirectly, by communicating unspoken aspects of the learner's cognitive state to potential agents of change (parents, teachers, siblings, friends); and (2) directly, by offering the learner a simpler way to express and explore ideas that may be difficult to think through in a verbal format, thus easing the learner's cognitive burden. As a result, the next decade may well offer evidence of gesture's dual potential as an illuminating tool for researchers and as a facilitator of cognitive growth for learners themselves. 相似文献
995.
王黎明 《贵阳学院学报(社会科学版)》2002,(1)
愉悦作为一种情感在艺术的殿堂是颇受人们欢迎的 ,也引起了不少人的关注。对当代艺术的愉悦性进行分析并讨论当代艺术愉悦的特点和它的影响。全文共分两个部分 :一 :愉悦性的特点 ;二 :愉悦性的负面影响 相似文献
996.
Yue-qin Qiu Xue-fen Yang Xian-yong Ma Yun-xia Xiong Zhi-mei Tian Qiu-li Fan Li Wang Zong-yong Jiang 《Journal of Zhejiang University. Science. B》2017,18(6):492-500
The expression of the cell death-inducing DNA fragmentation factor α-like effector (CIDE) family including Cidea, Cideb, and Cidec was significantly increased in mouse and human models of obesity. However, there was less information on these genes’ expression in pigs. Here, we hypothesized that different fat accumulation between lean (Duroc×Landrace×Yorkshire gilts, DLY) and obese (Lantang) pigs was attributed to porcine CIDE-modulating lipid metabolism. Our data showed that Cidea and Cidec were expressed at a high level in adipose tissue, and at a relatively high level in skeletal muscle, whereas Cideb was mainly expressed in the liver in both breeds of pig. Lantang pigs had higher white adipose and skeletal muscle Cidea and Cidec mRNA abundance, and hepatic and muscle Cideb mRNA than DLY pigs. Lipid metabolism-related genes including sterol regulatory element binding protein 1c (SREBP-1c), hepatocyte nuclear factor-4α (HNF-4α), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), fatty acid synthase (FASN), diacylglycerol O-acyltransferase 1 (DGAT1), and DGAT2 showed a higher expression level in adipose tissue from obese pigs than in that from lean pigs. Lantang pigs exhibited higher mRNA abundance for liver SREBP-1c, HNF-4α, and PGC-1α, and higher skeletal muscle SREBP-1c, HNF-4α, PGC-1α, and DGAT2 expression, as compared with DLY pigs. However, the perlipin2 mRNA levels in adipose tissues, liver, and skeletal muscle were significantly lower in obese pigs than in their lean counterparts. Furthermore, plasma non-esterified fatty acid (NEFA), glucose, and triacylglycerol (TAG) levels were greater in obese pigs than in lean pigs. Finally, data from correlation analysis further found that CIDE mRNA expression was positively correlated with back fat thickness (BFT), abdominal fat mass (AFM), and the levels of NEFA, TAG, and glucose in the two breeds. Collectively, these data revealed that the porcine CIDEs possibly modulated lipid metabolism and contributed to the development of fat deposition and obesity in Lantang pigs. 相似文献
997.
This paper reports on efforts aimed toward the development of more effective procedures for identifying mothers who are at elevated risk for problems in parenting. We present data from two independent samples of known maladaptors and corresponding comparison mothers and report on our attempts to cross-validate a promising screening instrument composed of items that index social support and parenting attitudes. The resultant 20-item scale correctly identified over 90% of maladaptive and comparison mothers. When this scale was cross-validated on a second independent sample of maladaptors and comparison mothers, it was again almost 90% accurate. Issues concerning the field application of this promising instrument are discussed and its possible limitations are considered. 相似文献
998.
利用计算机网络技术实现对高校教学档案的科学管理,对于促进高校档案管理现代化、信息网络化,资源共享具有重要的实践意义。文章介绍了基于Internet的高校教学档案信息管理系统(简称EAMIS)的体系结构和功能,阐述了开发EAMIS的主要技术和工具,并示范了EAMIS的一个“报表查询”模块的实现。 相似文献
999.
目的 :为探讨C -erbB - 2蛋白在胃癌、大肠癌和乳腺癌中表达的异同和意义。方法 :取胃癌 114例、大肠癌 10 4例和乳腺癌 10 6例 ,石蜡切片 ,SP免疫组织化学染色。结果 :C-erbB - 2在胃癌、大肠癌和乳腺癌中的阳性率分别为 71.9%、5 7.7%和 5 4 .7%。C -erbB - 2在胃癌和大肠癌中的表达与患者年龄有关 ;C -erbB - 2表达与大肠癌分化程度及乳癌恶性程度有关。结论 :C -erbB - 2高表达是大肠癌、乳癌恶性度高 ,预后不良的指标 相似文献
1000.
全光纤无源耦合器件制作过程中的实践创新能力培养 总被引:1,自引:0,他引:1
结合本科生毕业设计“全光纤光功率比耦合器件的制备”的实践过程,在理论上基于光波的耦合波方程,对熔融拉锥单模光纤耦合器的功率耦合比与拉伸长度、拉伸位置和损耗的关系进行数值模拟,使本科生在毕业设计的有限时间内掌握一种基本软件工具。通过设计过程中的实践活动,学生在指导教师的科研理念引导下,利用实验室现有的设备制作出2×2型、单窗口1×2型1550 nm和1310 nm宽带耦合器, 并完成了对制备出的光纤耦合器的光功率和光谱的检测。在实践教学过程中,突出体现了知识、能力、科研素质提高和创新能力的培养。通过无源耦合器件的制备,培养了学生的实践动手能力和科研思维能力, 为今后的学习或就业奠定了良好的基础。 相似文献