全文获取类型
收费全文 | 9413篇 |
免费 | 2477篇 |
国内免费 | 128篇 |
专业分类
耳鼻咽喉 | 372篇 |
儿科学 | 199篇 |
妇产科学 | 256篇 |
基础医学 | 234篇 |
口腔科学 | 171篇 |
临床医学 | 2924篇 |
内科学 | 1721篇 |
皮肤病学 | 307篇 |
神经病学 | 787篇 |
特种医学 | 340篇 |
外科学 | 1334篇 |
综合类 | 363篇 |
现状与发展 | 2篇 |
预防医学 | 1740篇 |
眼科学 | 100篇 |
药学 | 210篇 |
1篇 | |
中国医学 | 100篇 |
肿瘤学 | 857篇 |
出版年
2024年 | 80篇 |
2023年 | 411篇 |
2022年 | 119篇 |
2021年 | 267篇 |
2020年 | 500篇 |
2019年 | 176篇 |
2018年 | 565篇 |
2017年 | 607篇 |
2016年 | 621篇 |
2015年 | 716篇 |
2014年 | 723篇 |
2013年 | 1049篇 |
2012年 | 405篇 |
2011年 | 365篇 |
2010年 | 531篇 |
2009年 | 637篇 |
2008年 | 324篇 |
2007年 | 246篇 |
2006年 | 288篇 |
2005年 | 198篇 |
2004年 | 148篇 |
2003年 | 117篇 |
2002年 | 106篇 |
2001年 | 189篇 |
2000年 | 118篇 |
1999年 | 162篇 |
1998年 | 272篇 |
1997年 | 289篇 |
1996年 | 311篇 |
1995年 | 248篇 |
1994年 | 176篇 |
1993年 | 119篇 |
1992年 | 92篇 |
1991年 | 96篇 |
1990年 | 79篇 |
1989年 | 94篇 |
1988年 | 76篇 |
1987年 | 60篇 |
1986年 | 52篇 |
1985年 | 55篇 |
1984年 | 54篇 |
1983年 | 46篇 |
1982年 | 31篇 |
1981年 | 46篇 |
1980年 | 19篇 |
1979年 | 13篇 |
1978年 | 16篇 |
1977年 | 19篇 |
1976年 | 16篇 |
1975年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Vincent Moreau BA Gilles Bégin BSc Charles M. Morin PhD 《Residential treatment for children & youth》2013,30(1):21-35
The main objective of this study was to document sleep patterns and disturbances reported by youths temporarily living in residential care facilities. A secondary objective was to examine the relationships between sleep disturbances and mood and daytime sleepiness. A self-reported questionnaire on sleep patterns and habits assessing duration, frequency, and consequences of sleep difficulties, the Beck Depression Inventory-2, and the Epworth Sleepiness Scale were administered to a sample of 66 adolescents. Results suggest a high rate of sleep disturbances in this sample, with 41% reporting insomnia symptoms and 21% meeting diagnostic criteria for an insomnia syndrome. Those with more severe insomnia syndrome showed more severe depressive symptoms and daytime consequences. 相似文献
82.
83.
84.
85.
86.
Peripheral blood lymphocytes (PBLs) from multiple myeloma patients are defective in both proportion and absolute numbers of OKT4+ cells and have a normal proportion but reduced absolute number of OKT8+ cells. To assess the functional capabilities of the T cells in myeloma patients, we cloned the T cells in PBLs using limiting dilution conditions in which 100% of OKT4+ and OKT8+ T cells in normal PBLs are able to form a clone. In contrast, the OKT8+ cells from PBLs of five of seven multiple myeloma patients were severely compromised in their clonogenic potential; only 7% to 25% of OKT8+ T cells appeared to give rise to a clone. Clonogenic potential of the OKT4+ cells in patients was more nearly normal. Analysis of two multiple myeloma patients with abnormally low numbers of T cells in PBLs revealed the existence of abnormalities in the progenitors of T cell clones. In both patients, two to three times as many T cell clones were observed as would have been expected based on the number of PBLs cultured at limiting dilution, indicating that OKT4-8- cells in PBLs are capable of giving rise to OKT4+ and, at lower frequency, to OKT8+ clonal progeny in vitro. We conclude that purely quantitative assessment of T cell subsets should be interpreted with caution, since proportionately normal numbers of OKT8+ cells in patient PBLs are seriously compromised in their ability to give rise to clonal progeny in vitro, and since there appears to be a OKT4-8- population of T cells in PBLs that are committed to become OKT4+ or OKT8+ T cells, but are unable to do so in vivo. 相似文献
87.
Terrence M. Donohue Jr PhD James H. Sorrell BA Michael F. Sorrell MD Dean J. Tuma PhD 《Alcoholism, clinical and experimental research》1985,9(6):526-530
We investigated the utility of [3H]puromycin as an alternate and adjunct precursor to amino acids for measuring protein synthetic activity in rat liver slices. Slices were incubated in the presence of either [3H]puromycin or radiolabeled valine to compare the incorporation of these isotopic precursors into nascent hepatocellular proteins. Compared to liver slices from controls, comparable decreases in the incorporation of both [3H]puromycin and labeled valine were observed in experiments using slices from fasted rats and in slices preincubated with 25 mM ethanol. Radiolabeling of nascent polypeptides with either [3H]puromycin or labeled valine in liver slices from rats fed a liquid diet containing ethanol was also decreased compared to slices from pair-fed control and chow-fed animals. Our results demonstrated the validity of using [3H]puromycin to detect changes in protein synthetic activity under these conditions. The potential advantage of using [3H]puromycin for in vivo studies is discussed. 相似文献
88.
Russell F. Mankes PhD Rene LeFevre BA BS James Fieseher MA Anthony Santiago Karl-Fredrick Benitz MD Robert Lyon BS 《Alcoholism, clinical and experimental research》1985,9(3):284-290
Ethanol consumption and spontaneous (essential) hypertension are important fetal and maternal risk factors. Alone, they contribute to embryopathy (fetal alcohol syndrome) or maternal organ pathology and fetal loss in hypertensive pregnancies. Combined, the effects of ethanol consumption on the progress of a hypertensive pregnancy have not been adequately investigated. In the present study, groups of O-A strain genetic hypertensive (SHR: groups 1 and 2) and Wistar-Kyoto normotensive (WKY: groups 3 and 4) pregnant rats were given 20 ml/kg of distilled water by gavage to serve as controls [groups 1 (SHR) and 3 (WKY)] or 3.2 g/kg of ethanol [groups 2 (SHR) and 4 (WKY)] from days 6 to 15 of gestation. During acclimation, hypertension developed in SHR rats (WKY pressures were 105 to 114 mm Hg; SHR pressures were 137 to 148 mm Hg). From day 6 to 15 of gestation, ethanol-consuming rats (groups 2 and 4) had higher arterial pressures than controls (groups 1 and 3). Pregnant SHR rats given ethanol did not experience a prebirthing hypotension. On gestation day 20, most offspring (84%, group 2; 86%, group 4) of alcoholic dams were dead or malformed. Intrauterine growth retardation occurred in group 4. Hydrocephalus, microphthalmia, and mild hydronephrosis and hydroureter were common in live offspring of group 2 dams. Hydronephrosis and hydroureter were increased in group 4 pups. Variant cranial ossification was noted in group 2 and 4 pups. These preliminary data suggest an altered hypertensive response during pregnancy in alcohol-consuming rats and confirm the embryopathic effects of relatively high levels of ethanol consumed during the critical period of organogenesis in two additional strains of rats. 相似文献
89.
Acute appendicitis: CT and US correlation in 100 patients 总被引:18,自引:1,他引:18
90.
为研究超低频振动对人的视力、操作能力、胃电图、人体平衡稳定性和主观感觉的影响。实验采用0.25、0.5、0.63、0.8和1.0Hz五个振动频率,并参考之轴振动(头-足向)运动病频率范围,将实验结果按三个频段进行了分析。被试者取半仰卧位。结果表明,视力、操作能力、平衡稳定性不但与频率有关,而且随振动加速度的增加而降低。除视力外,它们随频率变化的规律符合所分频段含义,胃电图主频率改变和主观感觉级测试进一步说明了这一点。0.25Hz不仅处在Z轴全身振动的运动病敏感频段,而且也是X轴全身振动的敏感频率。因此,载人航天飞行中,不仅应避开0.25Hz的Z轴全身振动,而且也应避开0.25Hz的x轴全身振动。 相似文献