全文获取类型
收费全文 | 1886篇 |
免费 | 227篇 |
国内免费 | 114篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 88篇 |
妇产科学 | 24篇 |
基础医学 | 207篇 |
口腔科学 | 27篇 |
临床医学 | 223篇 |
内科学 | 456篇 |
皮肤病学 | 41篇 |
神经病学 | 84篇 |
特种医学 | 390篇 |
外国民族医学 | 1篇 |
外科学 | 171篇 |
综合类 | 154篇 |
预防医学 | 154篇 |
眼科学 | 17篇 |
药学 | 102篇 |
中国医学 | 1篇 |
肿瘤学 | 84篇 |
出版年
2022年 | 8篇 |
2021年 | 17篇 |
2020年 | 10篇 |
2019年 | 21篇 |
2018年 | 35篇 |
2017年 | 9篇 |
2016年 | 25篇 |
2015年 | 32篇 |
2014年 | 33篇 |
2013年 | 57篇 |
2012年 | 45篇 |
2011年 | 46篇 |
2010年 | 58篇 |
2009年 | 65篇 |
2008年 | 51篇 |
2007年 | 102篇 |
2006年 | 58篇 |
2005年 | 72篇 |
2004年 | 48篇 |
2003年 | 45篇 |
2002年 | 54篇 |
2001年 | 53篇 |
2000年 | 86篇 |
1999年 | 40篇 |
1998年 | 99篇 |
1997年 | 101篇 |
1996年 | 110篇 |
1995年 | 74篇 |
1994年 | 67篇 |
1993年 | 73篇 |
1992年 | 35篇 |
1991年 | 46篇 |
1990年 | 37篇 |
1989年 | 57篇 |
1988年 | 47篇 |
1987年 | 53篇 |
1986年 | 41篇 |
1985年 | 51篇 |
1984年 | 25篇 |
1983年 | 22篇 |
1982年 | 29篇 |
1981年 | 23篇 |
1980年 | 32篇 |
1979年 | 13篇 |
1978年 | 13篇 |
1977年 | 17篇 |
1976年 | 29篇 |
1975年 | 17篇 |
1974年 | 6篇 |
1970年 | 5篇 |
排序方式: 共有2227条查询结果,搜索用时 15 毫秒
1.
2.
Summary— To investigate if the functional alterations observed in resistance arteries of spontaneously hypertensive rats (SHRs) were also present at the coronary level, in vitro experiments were performed in mesenteric resistance arteries (MRA) and in right (RIC) and left interventricular coronary (LIC) arteries taken from 15–25-week-old SHR and age-matched Wistar Kyoto rats WKYs. Using a passive extension protocol, internal diameters corresponding to 100 mmHg intraluminal pressure (D100) were determined and vessels were set up to a normalized internal diameter (0.9 D100). SHR mesenteric resistance arteries had a significantly smaller diameter compared to WKY arteries, whereas both types of SHR coronary arteries had a greater diameter compared to those of WKY rats. In arteries in the absence of contracting agonist, nitro-L-arginine (NOLA, 100 μM) induced a progressive rise in basal tone, which could be reversed by subsequent addition of L-arginine (100 μM) but not D-arginine (100 μM). When expressed as percent of maximal contractions induced by agonists (noradrenaline, NA [10 μM] in MRA; serotonin, 5-HT [10 μM], in RIC and LIC), these contractions were significantly stronger in WKY compared to SHR coronary and mesenteric resistance arteries. In NA-precontracted MRA and 5HT-precontracted coronary arteries in the presence of indomethacin (10 μM), the magnitude of acetylcholine-induced maximal relaxations (expressed as percent of maximal contractions induced by agonists) was greater in WKY compared to SHR arteries. After a 30-min incubation period, NOLA (100 μM) completely inhibited relaxations induced by acetylcholine (0.01–10 μM) in all types of precontracted arteries. Subsequent additions of sodium nitroprusside, (SNP, 10 μM) induced complete relaxations in all preparations. These results show that a basal release of NO or NO-like compound by endothelial cells is present in isolated mesenteric resistance and coronary arteries of WKY rats and SHRs. The contribution of endothelium-derived relaxing factor-nitric oxide (EDRF-NO) to arterial tone was lower in MRA compared to coronary arteries in both strains and in SHR compared to WKY arteries. In the SHR preparations, the impaired relaxation induced by acetylcholine appeared to be due to a functional alteration of the endothelium in the presence of normal reactivity of the smooth muscle cells. 相似文献
3.
表小檗碱对α受体的作用 总被引:2,自引:0,他引:2
表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择 相似文献
4.
Vectorization of morpholino oligomers by the (R-Ahx-R)4 peptide allows efficient splicing correction in the absence of endosomolytic agents. 总被引:1,自引:0,他引:1
Sa?d Abes Hong M Moulton Philippe Clair Paul Prevot Derek S Youngblood Rebecca P Wu Patrick L Iversen Bernard Lebleu 《Journal of controlled release》2006,116(3):304-313
The efficient and non-toxic nuclear delivery of steric-block oligonucleotides (ON) is a prerequisite for therapeutic strategies involving splice correction or exon skipping. Cationic cell penetrating peptides (CPPs) have given rise to much interest for the intracellular delivery of biomolecules, but their efficiency in promoting cytoplasmic or nuclear delivery of oligonucleotides has been hampered by endocytic sequestration and subsequent degradation of most internalized material in endocytic compartments. In the present study, we compared the splice correction activity of three different CPPs conjugated to PMO(705), a steric-block ON targeted against the mutated splicing site of human beta-globin pre-mRNA in the HeLa pLuc705 splice correction model. In contrast to Tat48-60 (Tat) and oligoarginine (R(9)F(2)) PMO(705) conjugates, the 6-aminohexanoic-spaced oligoarginine (R-Ahx-R)(4)-PMO(705) conjugate was able to promote an efficient splice correction in the absence of endosomolytic agents. Our mechanistic investigations about its uptake mechanisms lead to the conclusion that these three vectors are internalized using the same endocytic route involving proteoglycans, but that the (R-Ahx-R)(4)-PMO(705) conjugate has the unique ability to escape from lysosomial fate and to access to the nuclear compartment. This vector, which has displays an extremely low cytotoxicity, the ability to function without chloroquine adjunction and in the presence of serum proteins. It thus offers a promising lead for the development of vectors able to enhance the delivery of therapeutic steric-block ON in clinically relevant models. 相似文献
5.
6.
7.
Controlled study of meso-2,3-dimercaptosuccinic acid for the management of childhood lead intoxication. 总被引:7,自引:0,他引:7
J H Graziano N J Lolacono T Moulton M E Mitchell V Slavkovich C Zarate 《The Journal of pediatrics》1992,120(1):133-139
We examined the efficacy and safety of meso-2,3-dimercaptosuccinic acid (DMSA) in children with markedly elevated blood lead (BPb) concentrations. Among 19 children with BPb concentrations of 50 to 69 micrograms/dl (2.41 to 3.33 mumol/L) who received a 5-day inpatient oral course of DMSA (1050 mg/m2 per day), the mean BPb concentration decreased by 61%; in four who received calcium disodium ethylenediaminetetraacetic acid (CaNa2EDTA) (1000 mg/m2 per day intravenously), it decreased by 45% (p less than 0.0007). Urinary lead excretion was comparable in both groups. Treatment with DMSA was more effective than treatment with CaNa2EDTA in restoring metabolic activity to the heme pathway and was well tolerated even among nine patients who received concomitant iron supplementation and two who had homozygous deficiency of glucose-6-phosphate dehydrogenase. On discharge, these 19 children received either no chelation therapy or DMSA, 350 or 700 mg/m2 per day for 14 days on an outpatient basis. After 14 days the mean BPb values for the no-chelation, low-DMSA, and high-DMSA groups were 73%, 66%, and 50% of the pretreatment values, respectively. We conclude that a 5-day oral course of DMSA is effective in the treatment of children with severe lead poisoning. In addition, on an outpatient basis the administration of DMSA, 700 mg/m2 per day, is capable of delaying the typical rebound in BPb values and should ultimately reduce the need for repeated hospitalizations. 相似文献
8.
9.
Lawrence H. Moulton Elizabeth A. Holt Jayakaran S. Job Neal A. Halsey 《Statistics in medicine》1995,14(8):777-787
Antibody responses following vaccination usually are analysed by comparing geometric mean concentrations across levels of relevant covariates and by comparing the proportions of vaccinees responding. In the regression setting, the analyses are done on log-transformed concentrations, estimating geometric mean responses conditional on a vector of covariates. More detailed analyses examining the relationship of covariates to different parts of the response distribution may be performed through the application of asymmetric least squares estimation of regression percentiles. We present a method for accounting for correlation in percentile regression analyses of longitudinal antibody response data. We illustrate the procedures with measles antibody response data from Haitian children who participated in a randomized trial of high titre vaccines. The strongest dose and strain effects were seen in the low end of the antibody concentration distributions. 相似文献
10.
Rupture of the distal biceps tendon: evaluation with MR imaging 总被引:2,自引:0,他引:2