全文获取类型
收费全文 | 2631篇 |
免费 | 18篇 |
国内免费 | 19篇 |
专业分类
教育 | 1484篇 |
科学研究 | 374篇 |
各国文化 | 3篇 |
体育 | 549篇 |
综合类 | 28篇 |
文化理论 | 6篇 |
信息传播 | 224篇 |
出版年
2024年 | 8篇 |
2023年 | 8篇 |
2022年 | 7篇 |
2020年 | 5篇 |
2016年 | 10篇 |
2015年 | 16篇 |
2014年 | 30篇 |
2013年 | 39篇 |
2012年 | 190篇 |
2011年 | 280篇 |
2010年 | 100篇 |
2009年 | 35篇 |
2008年 | 175篇 |
2007年 | 169篇 |
2006年 | 195篇 |
2005年 | 155篇 |
2004年 | 136篇 |
2003年 | 137篇 |
2002年 | 131篇 |
2001年 | 84篇 |
2000年 | 81篇 |
1999年 | 76篇 |
1998年 | 15篇 |
1997年 | 32篇 |
1996年 | 16篇 |
1995年 | 22篇 |
1994年 | 24篇 |
1993年 | 28篇 |
1992年 | 29篇 |
1991年 | 29篇 |
1990年 | 27篇 |
1989年 | 42篇 |
1988年 | 16篇 |
1987年 | 27篇 |
1986年 | 34篇 |
1985年 | 32篇 |
1984年 | 19篇 |
1983年 | 21篇 |
1982年 | 26篇 |
1981年 | 16篇 |
1979年 | 6篇 |
1960年 | 5篇 |
1959年 | 11篇 |
1958年 | 9篇 |
1957年 | 9篇 |
1956年 | 11篇 |
1955年 | 9篇 |
1954年 | 10篇 |
1951年 | 5篇 |
1937年 | 4篇 |
排序方式: 共有2668条查询结果,搜索用时 15 毫秒
52.
Kraft M 《Medical reference services quarterly》2007,26(1):27-35
Podcasts offer a way for medical professionals to listen to current information in medicine from an iPod, MP3 player, handheld device, or computer. As podcasts become more popular, libraries may be interested in integrating programs into the library collection. South Pointe Medical Library evaluated medical podcasts relevant to the scope of the library collection and explored methods for finding and organizing such programs in ways that are efficient for both the librarian and the patron. doi:10.1300/J115v26n01_03. 相似文献
53.
Objectives: To explore how the library service expectations and perceptions of users might differ across health‐related libraries as against major research libraries not operating in a medical context; to determine whether users of medical libraries demand better library service quality, because the inability of users to access needed literature promptly may lead to a patient who cannot be properly diagnosed, or a diagnosis that cannot be properly treated. Methodology: We compared LibQUAL+® total and subscale scores across three groups of US, Canadian and British libraries for this purpose. Results: Anticipated differences in expectations for health as other library settings did not emerge. Conclusions: The expectations and perceptions are similar across different types of health science library settings, hospital and academic, and across other general research libraries. 相似文献
54.
Marschark M 《Journal of deaf studies and deaf education》2007,12(2):125-126
55.
In this article we address "language approach" data as a key variable in quantitative, large-scale research on educational achievement, focusing on our work for the Achievements of Deaf Pupils in Scotland (ADPS) project. The complexity of approaches is addressed, with a particular focus on a "no-exclusion" model of service. In this context 3 years of language-related data are discussed, using constructions of language variables that take into account the variability in deaf pupils' hearing loss levels, types of provision, and professional practice. We see this as a necessary first step toward offering a nuanced context for understanding patterns in the educational outcomes among the ADPS population to be reported in a later article. The ADPS data on language approach can reveal general patterns at macro levels: our analysis suggests that, in Scotland, the extent and quality of British Sign Language/English provision may be determined more by local factors than by linguistic requirements and that ostensibly responsive policies can mask a limited spectrum for pupils and their families. However, the ADPS data are insufficiently sensitive to detailed and local variations to reflect the full complexity of language situations over time-a situation which represents an ongoing challenge for all long-term, large-scale studies. 相似文献
56.
57.
Perception of suprasegmental features of speech by children with cochlear implants and children with hearing AIDS 总被引:1,自引:0,他引:1
This study assessed perception of suprasegmental features of speech by 30 prelingual children with sensorineural hearing loss. Ten children had cochlear implants (CIs), and 20 children wore hearing aids (HA): 10 with severe hearing loss and 10 with profound hearing loss. Perception of intonation, syllable stress, word emphasis, and word pattern was assessed. Results revealed that the two HA groups significantly outperformed the CI group in perceiving both intonation and stress. Within each group, word pattern was perceived best, and then intonation and emphasis, with syllable stress perceived poorest. No significant correlation emerged between age at implantation and perception of the various suprasegmental features, possibly due to participants' relatively late age at implantation. Results indicated that CI use did not show an advantage over HA use in the perception of suprasegmental features of speech. Future research should continue to explore variables that might improve this perception. 相似文献
58.
Shalini M Yogeeswari P Sriram D Induja S 《Journal of Zhejiang University. Science. B》2007,8(1):45-55
Objective: To study the effect of halo substitution on disubstituted aryl semicarbazones on the anticonvulsant potential and model the activity based on quantum mechanics. Methods: A series of twenty-six compounds of N^4-(4-bromo-3-methylphenyl) semicarbazones were synthesized and evaluated for the anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure threshold tests. Some potential compounds were also tested in the subcutaneous strychnine (scSTY) and subcutaneous picrotoxin (scPIC) seizure threshold tests. The synthesized compounds were tested for behavioral impairment and CNS (central nervous system) depression in mice. Quantum mechanical modelling was carried out on these compounds to gain understanding on the structural features essential for activity. Results: Some compounds possessed broad spectrum anticonvulsant activity as indicated by their effect in pentylenetetrazole, strychnine, picrotoxin and maximal electroshock seizures models in resemblance to other aryl semicarbazone derivatives reported earlier. The higher the difference in HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels was, the greater was the activity profile. Conclusion: The pharmacophoric requirements for compounds to exhibit anticonvulsant activity that includes one aryl unit in proximity to a hydrogen donor-acceptor domain and an electron donor have been justified with the molecular orbital surface analysis of the synthesized compounds. 相似文献
59.
The bioactivity of the aqueous extracts of the leaf and stem bark of the medicinal plant, Alstonia boonei De Wild (Apocyanaceae), against the pink stalk borer, Sesamia calamistis Hampson (Lepidoptera: Noctuidae) was studied in a laboratory bioassay. The extracts were incorporated into artificial diet at a rate of 0.0% (control), 1.0%, 2.5%, 5.0%, and 10.0% (w/w). Both extracts significantly (P<0.01) reduced larval survival and weight in a dose dependent manner. The concentrations that killed 50% of the larvae (LC50) for the stem bark extract were 2.8% and 2.1% at 10 and 20 DAI (days after introduction), respectively, while those for the leaves extract were 5.6% and 3.5%. The weights of the larvae also varied significantly (P<0.05) between the treatments in a dose dependent manner. We conclude that both leaf and stem bark extracts of A. boonei are toxic, used as growth inhibitors to S. calamistis larvae, and hold good promise for use as alternative crop protectants against S. calamistis. 相似文献
60.
Pushpendra KG Harindra SB Pawan LK Neeraj K Ajay K Reyazul RM Amita M Jitendra K 《Journal of Zhejiang University. Science. B》2007,8(11):807-814
Quantitative trait loci (QTL) analysis was conducted in bread wheat for 14 important traits utilizing data from four different mapping populations involving different approaches of QTL analysis. Analysis for grain protein content (GPC) sug- gested that the major part of genetic variation for this trait is due to environmental interactions. In contrast, pre-harvest sprouting tolerance (PHST) was controlled mainly by main effect QTL (M-QTL) with very little genetic variation due to environmental interactions; a major QTL for PHST was detected on chromosome arm 3AL. For grain weight, one QTL each was detected on chromosome arms 1AS, 2BS and 7AS. QTL for 4 growth related traits taken together detected by different methods ranged from 37 to 40; nine QTL that were detected by single-locus as well as two-locus analyses were all M-QTL. Similarly, single-locus and two-locus QTL analyses for seven yield and yield contributing traits in two populations respectively allowed detection of 25 and 50 QTL by composite interval mapping (CIM), 16 and 25 QTL by multiple-trait composite interval mapping (MCIM) and 38 and 37 QTL by two-locus analyses. These studies should prove useful in QTL cloning and wheat improvement through marker aided selection. 相似文献