全文获取类型
收费全文 | 125180篇 |
免费 | 1889篇 |
国内免费 | 245篇 |
专业分类
教育 | 87262篇 |
科学研究 | 13730篇 |
各国文化 | 2061篇 |
体育 | 9590篇 |
综合类 | 175篇 |
文化理论 | 1118篇 |
信息传播 | 13378篇 |
出版年
2021年 | 950篇 |
2020年 | 1689篇 |
2019年 | 2620篇 |
2018年 | 3150篇 |
2017年 | 3451篇 |
2016年 | 3499篇 |
2015年 | 2411篇 |
2014年 | 3287篇 |
2013年 | 28087篇 |
2012年 | 2420篇 |
2011年 | 2771篇 |
2010年 | 2399篇 |
2009年 | 2694篇 |
2008年 | 2442篇 |
2007年 | 2180篇 |
2006年 | 2427篇 |
2005年 | 2411篇 |
2004年 | 3104篇 |
2003年 | 2402篇 |
2002年 | 2220篇 |
2001年 | 2020篇 |
2000年 | 1697篇 |
1999年 | 1585篇 |
1998年 | 1515篇 |
1997年 | 1584篇 |
1996年 | 1748篇 |
1995年 | 1549篇 |
1994年 | 1518篇 |
1993年 | 1510篇 |
1992年 | 1527篇 |
1991年 | 1440篇 |
1990年 | 1420篇 |
1989年 | 1333篇 |
1988年 | 1212篇 |
1987年 | 1131篇 |
1986年 | 1173篇 |
1985年 | 1427篇 |
1984年 | 1306篇 |
1983年 | 1295篇 |
1982年 | 1295篇 |
1981年 | 1205篇 |
1980年 | 1172篇 |
1979年 | 1263篇 |
1978年 | 1219篇 |
1977年 | 1142篇 |
1976年 | 1009篇 |
1975年 | 822篇 |
1974年 | 823篇 |
1973年 | 785篇 |
1971年 | 626篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
911.
912.
913.
914.
915.
916.
Danny Bavli Elishai Ezra Daniel Kitsberg Margarita Vosk-Artzi Shashi K. Murthy Yaakov Nahmias 《Biomicrofluidics》2016,10(2)
Cell-cell interactions play a key role in regeneration, differentiation, and basic tissue function taking place under physiological shear forces. However, current solutions to mimic such interactions by micro-patterning cells within microfluidic devices have low resolution, high fabrication complexity, and are limited to one or two cell types. Here, we present a microfluidic platform capable of laminar patterning of any biotin-labeled peptide using streptavidin-based surface chemistry. The design permits the generation of arbitrary cell patterns from heterogeneous mixtures in microfluidic devices. We demonstrate the robust co-patterning of α-CD24, α-ASGPR-1, and α-Tie2 antibodies for rapid isolation and co-patterning of mixtures of hepatocytes and endothelial cells. In addition to one-step isolation and patterning, our design permits step-wise patterning of multiple cell types and empty spaces to create complex cellular geometries in vitro. In conclusion, we developed a microfluidic device that permits the generation of perfusable tissue-like patterns in microfluidic devices by directly injecting complex cell mixtures such as differentiated stem cells or tissue digests with minimal sample preparation. 相似文献
917.
918.
This study sought to assess current and future school psychologists’ attitudes toward and preparedness to address the needs of lesbian, gay, bisexual, and transgender (LGBT) students in schools. Two‐hundred seventy‐nine school psychologists (n = 162, 58%) and school psychology graduate students (n = 117, 42%) were included in the study. Participants completed measures of attitudes toward LGBT students, preparedness to address the needs of LGBT youth, and social desirability. For both school psychologists and graduate students, increased education was associated with improved attitudes and increased preparedness to treat LGBT youth. For school psychologists, presence of a gay‐straight alliance was associated with increased knowledge about LGBT youth, as well as higher ratings of preparedness to treat LGBT youth; the same associations did not hold true for the graduate students. These findings have implications for the training and practice of school psychologists in addressing the needs of LGBT youth in schools. 相似文献
919.
920.