全文获取类型
收费全文 | 652篇 |
免费 | 54篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 19篇 |
妇产科学 | 14篇 |
基础医学 | 94篇 |
口腔科学 | 10篇 |
临床医学 | 63篇 |
内科学 | 134篇 |
皮肤病学 | 32篇 |
神经病学 | 64篇 |
特种医学 | 14篇 |
外科学 | 83篇 |
综合类 | 7篇 |
一般理论 | 2篇 |
预防医学 | 84篇 |
眼科学 | 11篇 |
药学 | 39篇 |
中国医学 | 2篇 |
肿瘤学 | 27篇 |
出版年
2023年 | 3篇 |
2022年 | 21篇 |
2021年 | 27篇 |
2020年 | 24篇 |
2019年 | 26篇 |
2018年 | 26篇 |
2017年 | 19篇 |
2016年 | 25篇 |
2015年 | 29篇 |
2014年 | 29篇 |
2013年 | 40篇 |
2012年 | 53篇 |
2011年 | 44篇 |
2010年 | 25篇 |
2009年 | 22篇 |
2008年 | 35篇 |
2007年 | 45篇 |
2006年 | 33篇 |
2005年 | 28篇 |
2004年 | 27篇 |
2003年 | 29篇 |
2002年 | 17篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 11篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 5篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1964年 | 1篇 |
1929年 | 1篇 |
排序方式: 共有708条查询结果,搜索用时 0 毫秒
1.
P Goya J A Paez I Alkorta E Carrasco M Grau F Anton S Julia M Martinez-Ripoll 《Journal of medicinal chemistry》1992,35(22):3977-3983
The synthesis and evaluation of a new class of diuretic agents derived from the pyrazino[2,3-c][1,2,6]thiadiazine 2,2-dioxide ring system are described. Preliminary structure-activity relationships indicate that the nature and location of the substituents at different positions of the heterocycle are crucial for activity. Thus, a novel synthetic methodology has been developed to selectively introduce the desired substituents at different positions. From the study of the pharmacological properties (dose-response curves, duration of action, and acute toxicity) of the most active compounds, 4-amino-1,7-diethyl-6-methylpyrazino[2,3-c][1,2,6]thiadiazine++ + 2,2-dioxide (9) was selected for further investigation. Compound 9 (C10H15N5O2S) crystallizes in space group P21/a with unit cell dimensions a = 16.482 (1), b = 9.3484 (3), c = 8.333 (3) A, beta = 103.003 (3) degrees, Z = 4. 相似文献
2.
Rada P Tucci S Teneud L Paez X Perez J Alba G García Y Sacchettoni S del Corral J Hernandez L 《Journal of chromatography. B, Biomedical sciences and applications》1999,735(1):1-10
Due to its low electrophoretic mobility, few studies have been able to measure gamma aminobutyric acid (GABA) in biological samples by means of capillary zone electrophoresis. Nevertheless, in micellar electrokinetic chromatography (MEKC) by adding a surfactant to the mobile phase separation can be carried out on the basis of the partition coefficient of the molecules rather than their electrophoretic mobility. In the present study microdialysis coupled to MEKC with laser induced fluorescence detection was used to successfully monitor GABA from cerebrospinal fluid and plasma dialysates. Moreover, we monitored changes in extracellular GABA from a human brain. Microdialysis samples were collected from a Parkinson's disease patient undergoing a thallamotomy as part of her treatment. Significant decreases in extracellular GABA were detected during high frequency electrical stimulation and following a thermolesion of the thalamus. These results demonstrate the feasibility of MEKC coupled to laser-induced fluorescence detection in resolving neutral amino acids, specifically GABA, from different human body fluids. 相似文献
3.
Analysis of ALK-1 and endoglin in newborns from families with hereditary hemorrhagic telangiectasia type 2 总被引:9,自引:0,他引:9
Abdalla SA Pece-Barbara N Vera S Tapia E Paez E Bernabeu C Letarte M 《Human molecular genetics》2000,9(8):1227-1237
ALK-1 (activin receptor-like kinase-1), a type I receptor of the transforming growth factor (TGF)-beta superfamily, is the gene mutated in hereditary hemorrhagic telangiectasia type 2 (HHT2) while endoglin is mutated in HHT1. Using a novel polyclonal antibody to ALK-1, we measured ALK-1 expression on human umbilical vein endothelial cells (HUVEC) of newborns from HHT families whose affected members had normal endoglin levels. ALK-1 levels were specifically reduced in three HUVEC with ALK-1 missense mutant codons, and normal in two newborns not carrying the missense mutations present in the clinically affected relatives. Levels were also normal in a HUVEC with deletion of S232 in the ATP binding site of ALK-1. Thus HHT2 appears to be associated with a loss of function of the mutant allele due to a reduction in either protein level or activity. We also report three new ALK-1 missense mutations leading to G48E/A49P, C344Y and E407D substitutions. In COS-1 transfected cells, ALK-1 was found in the TGF-beta1 and -beta3 receptor complexes in association with endoglin and TbetaRII, but not in activin receptor complexes containing endoglin. In HUVEC, ALK-1 was not detectable in the TGF-beta1 or -beta3 receptor complexes. However, in the absence of ligand, ALK-1 and endoglin interactions were observed by immunoprecipitation/western blot in HUVEC from normal as well as HHT1 and HHT2 patients. Our data suggest a transient association between these two proteins of the TGF-beta superfamily, both required at a critical level to ensure vessel wall integrity. 相似文献
4.
5.
Rico H Roca-Botran C Hernández ER Seco C Paez E Valencia MJ Villa LF 《Menopause (New York, N.Y.)》2000,7(6):413-416
OBJECTIVE: The effect of a copper supplement on preventing bone mass loss induced by ovariectomy in rats was investigated. DESIGN: Three groups of fifteen 100-day-old female Wistar rats, each with a mean initial weight of approximately 260 g per animal, were selected for a 30-day experiment. One group of 15 ovariectomized rats was fed a diet supplemented with 15 mg of copper per kilogram of feed. The other two groups: 15 ovariectomized and 15 Sham- ovariectomized rats did not receive the supplement. Morphometric (weight and length) and densitometric studies with dual-energy x-ray absorptiometry were performed on the whole femur and the fifth lumbar vertebra of each animal at the end of the 30-day period. RESULTS: The ovariectomized rat group fed a diet supplemented with copper did not show the bone mass loss at the axial (fifth lumbar vertebra) or peripheral (femur) level that was evidenced in the ovariectomized group. CONCLUSIONS: The results of the measurement of axial and peripheral bones show that a supplement of copper may have a potential therapeutic application in the treatment and prevention of involutional osteoporosis. 相似文献
6.
Szwarcwald CL Bastos FI Esteves MA de Andrade CL Paez MS Medici EV Derrico M 《Cadernos de saúde pública / Ministério da Saúde, Funda??o Oswaldo Cruz, Escola Nacional de Saúde Pública》1999,15(1):15-28
This ecological analysis addresses the association between income inequality and health status in the municipality of Rio de Janeiro. Data were analyzed using geo-processing and multiple regression techniques. The following health indicators were used: infant mortality rate; standardized mortality rate; life expectancy at birth; and homicide rate among 15-29-year-old males. Patterns of income inequality were assessed through income distribution indicators: Gini index, Robin Hood index, and top 10 %/bottom 40% average income ratio. The results indicate significant correlations between income distribution indicators and health indicators, providing additional empirical evidence of the association between health status and income inequality. For the homicide rate, the effect of the indicator "density of slum residents" was also relevant, suggesting that further deterioration in health standards may be due to social disruption of deprived communities and the resultant increase in criminal activity. The geo-epidemiological analysis presented here highlights the association between adverse health outcomes and residential concentration of poverty. Social policies focused on slum residents are needed to reduce the harmful effects of relative deprivation. 相似文献
7.
Medial prefrontal cortex (MPFC) transection enhances social interaction in an open arena test. Social interaction enhances dopaminergic activity in the nucleus accumbens (NAC). In the present set of experiments, microdialysis probes were implanted in the NAC, and glutamate, gamma-aminobutyric acid (GABA) and dopamine (DA) were measured during electrical stimulation of the MPFC, after coronal transection caudal to the MPFC and after a systemic injection of amphetamine in transected rats. Electrical stimulation of the MPFC caused a transient enhancement of glutamate release in the NAC, no change in GABA levels and a long lasting increase in DA levels. Medial prefrontal transection did not change basal glutamate or GABA levels in the NAC, but increased basal DA levels. Amphetamine administration decreased GABA levels in medial prefrontal transected rats, had no effect on glutamate and increased DA levels more than in controls. The experiments suggest that glutamatergic activity in the accumbens decreases dopamine release. Medial prefrontal transection reduces glutamatergic tone and enhances dopamine release, which probably decreases GABAergic activity in the NAC. Presumably, GABA inhibition in the NAC enhances social interaction. 相似文献
8.
Andreas Hoefer Silvia Herrera-Len Lucas Domínguez Maria Ordobs Gavín Beatriz Romero Ximena Belen Araujo Piedra Cristina Sobrino Calzada María Jos Uría Gonzlez Laura Herrera-Len Case Study Investigation Group 《Emerging infectious diseases》2022,28(6):1257
Toxigenic Corynebacterium ulcerans is as an emerging zoonotic agent of diphtheria. We describe the zoonotic transmission of diphtheria caused by toxigenic C. ulcerans from domestic animals in Spain, confirmed by core-genome multilocus sequence typing. Alongside an increasing number of recent publications, our findings highlight the public health threat posed by diphtheria reemergence. 相似文献
9.
Kevin E. Bennet Kendall H. Lee James N. Kruchowski Su-Youne Chang Michael P. Marsh Alexander A. Van Orsow Aurelio Paez Felicia S. Manciu 《Materials》2013,6(12):5726-5741
Building on diamond characteristics such as hardness, chemical inertness and low electron emission threshold voltage, the current microscopic, spectroscopic and voltammetric investigations are directed towards improving the properties of electrode coating materials for their future use in clinical studies of deep brain stimulation via fast-scan cyclic voltammetry (FSCV). In this study we combine the capabilities of confocal Raman mapping in providing detailed and accurate analysis of local distributions of material constituents in a series of boron-doped polycrystalline diamond films grown by chemical vapor deposition, with information from the more conventional techniques of scanning electron microscopy (SEM) and infrared absorption spectroscopy. Although SEM images show a uniform distribution of film crystallites, they have the limitation of being unable to differentiate the distribution of boron in the diamond. Values of 1018–1021 atoms/cm3 of boron content have been estimated from the absorption coefficient of the 1290 cm−1 infrared absorption band and from the 500 cm−1 Raman vibration. The observed accumulation of boron atoms and carbon sp2 impurities at the grain boundaries suggests that very high doping levels do not necessarily contribute to improvement of the material’s conductivity, corroborating with voltammetric data. FSCV results also indicate an enhanced stability of analyte detection. 相似文献
10.
Ximena Terra PhD Teresa Auguet MD PhD Zaida Agüera MSc Isabel Maria Quesada Josep Maria Orellana‐Gavaldà PhD Carmen Aguilar PhD Susana Jiménez‐Murcia PhD Alba Berlanga MSc Esther Guiu‐Jurado MSc José Manuel Menchón MD Fernando Fernández‐Aranda PhD Cristóbal Richart MD PhD 《The International journal of eating disorders》2013,46(8):855-861