全文获取类型
收费全文 | 19961篇 |
免费 | 144篇 |
国内免费 | 8篇 |
专业分类
教育 | 15002篇 |
科学研究 | 1848篇 |
各国文化 | 164篇 |
体育 | 1018篇 |
综合类 | 3篇 |
文化理论 | 505篇 |
信息传播 | 1573篇 |
出版年
2022年 | 56篇 |
2021年 | 95篇 |
2020年 | 154篇 |
2019年 | 223篇 |
2018年 | 2421篇 |
2017年 | 2340篇 |
2016年 | 1833篇 |
2015年 | 351篇 |
2014年 | 375篇 |
2013年 | 1945篇 |
2012年 | 450篇 |
2011年 | 903篇 |
2010年 | 1032篇 |
2009年 | 619篇 |
2008年 | 907篇 |
2007年 | 1337篇 |
2006年 | 301篇 |
2005年 | 592篇 |
2004年 | 596篇 |
2003年 | 552篇 |
2002年 | 294篇 |
2001年 | 143篇 |
2000年 | 139篇 |
1999年 | 117篇 |
1998年 | 115篇 |
1997年 | 125篇 |
1996年 | 117篇 |
1995年 | 125篇 |
1994年 | 119篇 |
1993年 | 96篇 |
1992年 | 114篇 |
1991年 | 111篇 |
1990年 | 102篇 |
1989年 | 93篇 |
1988年 | 84篇 |
1987年 | 71篇 |
1986年 | 67篇 |
1985年 | 73篇 |
1984年 | 60篇 |
1983年 | 77篇 |
1982年 | 73篇 |
1981年 | 78篇 |
1980年 | 82篇 |
1979年 | 75篇 |
1978年 | 54篇 |
1977年 | 45篇 |
1976年 | 55篇 |
1975年 | 44篇 |
1974年 | 40篇 |
1971年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
201.
202.
Troubleshooting electronic resource linking issues can seem to be an insurmountable task—so many resources, so little time. Using interlibrary loan (ILL) data on requests for materials available online, the electronic resources staff at the Samford University Library detected problems with the implementation of their new link resolver. This data also provided a window into some systemic issues within the metadata of certain sources and the link resolver knowledgebase. In addition to helping us improve linking for our users, the establishment of a workflow for communicating cancelled ILL transaction data on an ongoing basis has also improved the communication between electronic resources staff and the ILL department regarding the overall linking process. 相似文献
203.
204.
Gamified teaching is a pedagogical strategy that utilizes principles of gaming in the structure of assignments and grading. When students are allowed to engage in gameful educational experiences, they are given the freedom to choose their own pathway through assignments in order to better customize their learning. This article presents a rationale for gamified teaching and outlines the various elements of this instructional approach. In addition, guidance is provided on how to convert a traditional course to a gamified class. 相似文献
205.
JIANG Ren-jie QI Fei-hu XU Li WU Guo-rong ZHU Kai-hua 《浙江大学学报(A卷英文版)》2007,8(4):568-574
This paper proposes a learning-based method for text detection and text segmentation in natural scene images. First, the input image is decomposed into multiple connected-components (CCs) by Niblack clustering algorithm. Then all the CCs including text CCs and non-text CCs are verified on their text features by a 2-stage classification module, where most non-text CCs are discarded by an attentional cascade classifier and remaining CCs are further verified by an SVM. All the accepted CCs are output to result in text only binary image. Experiments with many images in different scenes showed satisfactory performance of our proposed method. 相似文献
206.
INTRODUCTION There is increased need in recent years for strengthening or rehabilitation of existing reinforced concrete structures adversely affected by overloading, construction material deterioration, seismic loads, structural deformation, etc. An effective method for increasing the shear capacity of reinforced concrete columns is the use of externally bonded carbon fiber reinforced plastic (CFRP) systems (ACI, 2002). FRP systems were first applied to reinforced concrete col-umns i… 相似文献
207.
Sovichea Lay Hai-ning Yu Bao-xiang Hu Sheng-rong Shen 《Journal of Zhejiang University. Science. B》2016,17(6):465-475
A pre-treatment methodology for clenbuterol hydrochloride (CLEN) isolation and enrichment in a complex matrix environment was developed through exploiting molecularly imprinted polymers (MIPs). CLEN-imprinted polymers were synthesized by the combined use of ally-β-cyclodextrin (ally-β-CD) and methacrylic acid (MAA), allyl-β-CD and acrylonitrile (AN), and allyl-β-CD and methyl methacrylate (MMA) as the binary functional monomers. MAA-linked allyl-β-CD MIPs (M-MAA) were characterized by Fourier transform-infrared (FT-IR) spectroscopy and a scanning electron microscope (SEM). Based upon the results, M-MAA polymers generally proved to be an excellent selective extraction compared to its references: AN-linked allyl-β-CD MIPs (M-AN) and MMA-linked allyl-β-CD MIPs (M-MMA). M-MAA polymers were eventually chosen to run through a molecularly imprinted solid-phase extraction (MISPE) micro-column to enrich CLEN residues spiked in pig livers. A high recovery was achieved, ranging from 91.03% to 96.76% with relative standard deviation (RSD) ≤4.45%. 相似文献
208.
Hui-ping Lin Jun Lin Juan Li Jing-hong Xu Christian Mehl 《Journal of Zhejiang University. Science. B》2016,17(11):864-873
Resin-dentin bond degradation is a major cause of restoration failures. The major aim of the current study was to evaluate the impact of a remineralization medium on collagen matrices of hybrid layers of three different adhesive resins using nanotechnology methods. Coronal dentin surfaces were prepared from freshly extracted premolars and bonded to composite resin using three adhesive resins (FluoroBond II, Xeno-III-Bond, and iBond). From each tooth, two central slabs were selected for the study. The slabs used as controls were immersed in a simulated body fluid (SBF). The experimental slabs were immersed in a Portland cement-based remineralization medium that contained two biomimetic analogs (biomineralization medium (BRM)). Eight slabs per group were retrieved after 1, 2, 3, and 4 months, respectively and immersed in Rhodamine B for 24 h. Confocal laser scanning microscopy was used to evaluate the permeability of hybrid layers to Rhodamine B. Data were analyzed by analysis of variance (ANOVA) and Tukey’s honest significant difference (HSD) tests. After four months, all BRM specimens exhibited a significantly smaller fluorescent area than SBF specimens, indicating a remineralization of the hybrid layer (P≤0.05). A clinically applicable biomimetic remineralization delivery system could potentially slow down bond degradation. 相似文献
209.
This study is designed to identify the underlying satisfaction dimensions gained through engagement in target shooting as a serious leisure pastime. The instrument design was based on the Leisure Satisfaction Scale. A total of 5502 useable surveys were collected through the Internet and a website related to target shooting and gun ownership. The results revealed eight dimensions: self-actualization, social interaction, location aesthetic, respite, physical benefit, connection and hedonic pleasure, which supplied the primary satisfiers of engaging in target shooting as a serious leisure activity. The demographic profile and dimensions of satisfaction may serve to dispel commonly held stereotypes of shooting hobbyists and those involved in gun ownership. The findings have important implications for leisure researchers and practitioners, to industry, both leisure and firearm related, and the target shooting community at large. This study adds to the literature of both target shooting and serious leisure. 相似文献
210.