全文获取类型
收费全文 | 345篇 |
免费 | 18篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 12篇 |
妇产科学 | 8篇 |
基础医学 | 29篇 |
口腔科学 | 2篇 |
临床医学 | 35篇 |
内科学 | 58篇 |
皮肤病学 | 6篇 |
神经病学 | 34篇 |
特种医学 | 40篇 |
外科学 | 39篇 |
综合类 | 3篇 |
预防医学 | 25篇 |
眼科学 | 6篇 |
药学 | 10篇 |
肿瘤学 | 52篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 13篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 11篇 |
2015年 | 17篇 |
2014年 | 9篇 |
2013年 | 27篇 |
2012年 | 21篇 |
2011年 | 20篇 |
2010年 | 10篇 |
2009年 | 8篇 |
2008年 | 25篇 |
2007年 | 20篇 |
2006年 | 24篇 |
2005年 | 20篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 12篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有363条查询结果,搜索用时 15 毫秒
1.
2.
Vakil E Hornik C Levy DA 《The journals of gerontology. Series B, Psychological sciences and social sciences》2008,63(3):P171-P175
We examined the hypothesis that older adults' deficits in contextual memory result from difficulties in contending with partial encoding-to-retrieval changes in the context. We measured effects of contextual change and constancy on recognition memory for words, in older and younger adults. We assessed the ability to adjust to partial contextual changes by manipulating encoding-retrieval context similarity: identical, new and unrelated, conceptually similar, or perceptually similar. For both older and younger adults, identical and conceptually similar contexts benefited recognition of target words, whereas perceptually similar contexts did not. Older adults did not make more false alarms. In contrast, older adults' direct recognition of contextual stimuli was at chance. These results indicate that retrieval processes, rather than encoding or rigidity in the use of contextual cues, are implicated in older adults' difficulties in memory for contextual information. 相似文献
3.
4.
Second cancer risk in childhood cancer survivors treated with intensity‐modulated radiation therapy (IMRT) 下载免费PDF全文
5.
Direct effects of luteinizing hormone-releasing hormone agonists and antagonists on MCF-7 mammary cancer cells. 总被引:2,自引:0,他引:2 下载免费PDF全文
T Segal-Abramson H Kitroser J Levy A V Schally Y Sharoni 《Proceedings of the National Academy of Sciences of the United States of America》1992,89(6):2336-2339
The binding of luteinizing hormone-releasing hormone (LH-RH) analogues to the human mammary tumor cell line MCF-7 and their effect on the cell proliferation was studied to elucidate their direct action on estrogen-dependent mammary tumors. The growth rate of these cells was doubled by the addition of 1 nM estradiol to cells maintained in an estrogen-deficient medium. Although the basal growth rate was only slightly inhibited by the LH-RH antagonist [Ac-D-Nal(2)1,D-Phe(pCl)2,D-Pal(3)3,D-Cit6,D-Ala10]LH-RH (SB-75), the estrogen-stimulated growth was completely abolished by the antagonist. In contrast, the LH-RH agonist buserelin stimulated cell growth in estrogen-deficient medium, whereas it had no effect in the presence of estrogen. 125I-labeled buserelin was used for the measurement of LH-RH receptors on MCF-7 cells. A Scatchard plot analysis of buserelin-specific binding revealed a nonlinear plot, which suggested the presence of one high-affinity binding site with a Kd of 1.4 +/- 1.0 nM and the remaining sites with low affinity (Kd = 1.3 +/- 1.0 microM). The binding of 125I-labeled buserelin was displaced equally well by unlabeled buserelin and by the LH-RH antagonist SB-75, suggesting that both analogues are bound to the same receptor. When parallel experiments were performed with 125I-labeled SB-75, the binding was displaced by unlabeled SB-75 and other antagonists, but only partially displaced by unlabeled buserelin. The results suggest that in these mammary tumor cells there is a LH-RH antagonist binding site that is not recognizable by LH-RH agonists. This hypothesis was tested by measuring cell growth in the presence of both agonists and antagonists. It was found that SB-75 inhibited the stimulation of growth by buserelin, but buserelin did not prevent the inhibition by the antagonist of the estrogen-dependent growth. These results suggest that antagonists directly inhibit mammary tumor growth, not only by competing with LH-RH high-affinity receptors, but also by other mechanisms mediated by low-affinity antagonist binding sites. 相似文献
6.
Background: Accurate measurement of neonatal neurological integrity is critical for early identification of pre-term and full-term infants at-risk for developmental disability. The Neurobehavioural Assessment for Pre-term Infants (NAPI) was developed to measure the progression of neurobehavioural development in pre-term infants born between 32 weeks post-conceptional age (PCA) and term. This instrument has many unique advantages; however, criterion validity is unknown and results are subsequently difficult to interpret. Objectives: This study examined the concurrent validity of the NAPI against a criterion instrument, the Einstein Neonatal Neurobehavioural Assessment Scale (ENNAS), which measures similar constructs and has demonstrated excellent reliability and validity. Methods: A sample of 41 pre-term and full-term infants (40?±?2 weeks) was assessed with the NAPI and ENNAS on the same day. Results: The findings demonstrated that correlations between similar NAPI clusters and ENNAS clusters ranged from 0.35–0.65 and correlations between many similar individual NAPI and ENNAS items ranged from 0.40–0.60. Two NAPI clusters also discriminated between normal, abnormal and suspect performance on the ENNAS. Conclusion: The NAPI has many unique advantages as a tool. It examines neonates serially, has established weekly normative data and requires minimal infant handling. This study provides new validation of the NAPI instrument. 相似文献
7.
8.
9.
Katherine E Burdick Raphael J Braga Chaya B Gopin Anil K Malhotra 《Neuropsychopharmacology》2014,39(2):274-282
We recently reported that the D2/D3 agonist pramipexole may have pro-cognitive effects in euthymic patients with bipolar disorder (BPD); however, the emergence of impulse-control disorders has been documented in Parkinson''s disease (PD) after pramipexole treatment. Performance on reward-based tasks is altered in healthy subjects after a single dose of pramipexole, but its potential to induce abnormalities in BPD patients is unknown. We assessed reward-dependent decision making in euthymic BPD patients pre- and post 8 weeks of treatment with pramipexole or placebo by using the Iowa Gambling Task (IGT). The IGT requires subjects to choose among four card decks (two risky and two conservative) and is designed to promote learning to make advantageous (conservative) choices over time. Thirty-four BPD patients completed both assessments (18 placebo and 16 pramipexole). Baseline performance did not differ by treatment group (F=0.63; p=0.64); however, at week 8, BPD patients on pramipexole demonstrated a significantly greater tendency to make increasingly high-risk, high-reward choices across the five blocks, whereas the placebo group''s pattern was similar to that reported in healthy individuals (treatment × time × block interaction, p<0.05). Analyses of choice strategy using the expectancy valence model revealed that after 8 weeks on pramipexole, BPD patients attended more readily to feedback related to gains than to losses, which could explain the impaired learning. There were no significant changes in mood symptoms over the 8 weeks, and no increased propensity toward manic-like behaviors were reported. Our results suggest that the enhancement of dopaminergic activity influences risk-associated decision-making performance in euthymic BPD. The clinical implications remain unknown. 相似文献