全文获取类型
收费全文 | 4713篇 |
免费 | 436篇 |
国内免费 | 85篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 221篇 |
妇产科学 | 77篇 |
基础医学 | 612篇 |
口腔科学 | 121篇 |
临床医学 | 622篇 |
内科学 | 928篇 |
皮肤病学 | 71篇 |
神经病学 | 306篇 |
特种医学 | 404篇 |
外国民族医学 | 1篇 |
外科学 | 508篇 |
综合类 | 126篇 |
一般理论 | 5篇 |
预防医学 | 499篇 |
眼科学 | 55篇 |
药学 | 274篇 |
中国医学 | 8篇 |
肿瘤学 | 380篇 |
出版年
2021年 | 50篇 |
2019年 | 52篇 |
2018年 | 54篇 |
2017年 | 50篇 |
2016年 | 51篇 |
2015年 | 69篇 |
2014年 | 84篇 |
2013年 | 164篇 |
2012年 | 162篇 |
2011年 | 184篇 |
2010年 | 118篇 |
2009年 | 126篇 |
2008年 | 199篇 |
2007年 | 190篇 |
2006年 | 152篇 |
2005年 | 143篇 |
2004年 | 177篇 |
2003年 | 159篇 |
2002年 | 167篇 |
2001年 | 173篇 |
2000年 | 140篇 |
1999年 | 136篇 |
1998年 | 123篇 |
1997年 | 120篇 |
1996年 | 100篇 |
1995年 | 91篇 |
1994年 | 78篇 |
1993年 | 80篇 |
1992年 | 123篇 |
1991年 | 93篇 |
1990年 | 100篇 |
1989年 | 112篇 |
1988年 | 96篇 |
1987年 | 100篇 |
1986年 | 88篇 |
1985年 | 103篇 |
1984年 | 71篇 |
1983年 | 56篇 |
1982年 | 43篇 |
1980年 | 43篇 |
1979年 | 71篇 |
1978年 | 40篇 |
1977年 | 39篇 |
1975年 | 40篇 |
1974年 | 43篇 |
1973年 | 47篇 |
1972年 | 50篇 |
1971年 | 45篇 |
1969年 | 46篇 |
1968年 | 39篇 |
排序方式: 共有5234条查询结果,搜索用时 187 毫秒
41.
Human parvovirus B19 commonly infects children, causing erythema infectiosum (fifth disease). However, there is a significant adult population which has not been exposed to the virus and, consequently, does not have protective antibody. Recent reports have associated B19 infection during pregnancy with fetal death, although normal outcome of pregnancy is more common. To characterise further the role of B19 infection in fetal deaths, a series of laboratory investigations has been undertaken on tissues obtained at autopsy. These have demonstrated the presence of virion-sized DNA by Southern blotting, viral antigen by radioimmunoassay, and viral particles by electron microscopy, all from tissues of hydrops fetalis. These data confirm that the human parvovirus B19 can cross the placenta and replicate in fetal tissues. 相似文献
42.
43.
Eme L Iloeje Michael J. Katovich Edward E. Soltis F. Peter Field 《Pharmaceutical research》1985,2(6):298-301
Alterations in - and -adrenergic responsiveness were investigated prior to and during the development of hypertension in rats treated with desoxycorticosterone acetate and NaCl (DOCA/ NaCl). The DOCA/NaCl rats became noticeably hypertensive (> 150 mm Hg) six weeks after the initiation of treatment. Prior to the development of hypertension, a reduced in vivo and in vitro - and an enhanced -adrenergic responsiveness of the DOCA/NaCl group resulted. At 2 and 12 weeks of the study, the dipsogenic response to isoproterenol was significantly attenuated in the DOCA/NaCl rats, whereas no difference in the dipsogenic response to 24 hour water deprivation was observed between control and DOCA/NaCl rats. Isoproterenol-induced relaxation of aortic smooth muscle from the DOCA/NaCl treated rats was significantly reduced at 4 weeks and further attenuated at 12 weeks of the study. However, aortic smooth muscle sensitivity to norepinephrine stimulation was significantly increased at 4 and 12 weeks of the study. These results suggest that alterations in both in vivo and in vitro - and -adrenergic responsiveness occur prior to establishment of hypertension of the DOCA/NaCl rats and that these alterations may have a role in the early stages of the development of this form of hypertension. 相似文献
44.
J C Thomas L L Wiltse E H Widell C W Spencer M R Zindrick B T Field 《Clinical orthopaedics and related research》1986,(206):61-66
An 11.8-year median follow-up evaluation of 42 "ideal" patients who had chemonucleolysis was obtained by examination, questionnaire, and roentgenograms. The excellent and good rating of this group was 81%, as compared to the total of 135 patients previously evaluated at 42 months and showing 85.2%. No complications were noted. Disc space rewidening, after initial narrowing, was observed in eight patients and 26% of all discs injected. While all who showed rewidening had excellent results, widening was not necessary to achieve an excellent rating. Marked narrowing and sclerosis of intervertebral margins were seen in many excellent and good clinical results. Chemonucleolysis represents a viable option as definitive treatment for a herniated nucleus pulposus in carefully selected patients. 相似文献
45.
46.
47.
1 病例报告 女 ,45岁 ,因吞咽困难 16 mo伴发热 15 d,于1999- 0 7- 12入院 .于 16 mo前与人争吵后出现吞咽困难 ,以进食馒头、面条为著 ,剑突下有时出现梗噎感 ,随即呕吐 ,呕出所进食物及粘液 ,情绪波动可诱发症状加重 ,伴食欲减退、返酸 .15 d前无诱因出现不规则发热 ,T38~ 39℃ ,上腹痛加重 ,全身酸困不适 ,乏力、头晕、消瘦 .追问病史 ,患者 5 a前双手、足疼痛麻木 ,尤以受凉、精神刺激后明显 ,手指初发白 ,继而发紫 ,变红 ,且麻木疼痛加重 ,手足小关节渐僵硬、畸形 .曾到多家医院就诊 ,诊断 :“雷诺病、类风湿性关节炎”.2 a前出现… 相似文献
48.
Kiaris H Jones A Spandidos D Vaughan E Field J 《International journal of oncology》1994,5(6):1243-1248
LOH studies provide evidence for the implication of novel TSGs in human tumours. The p arm of chromosome 8 has been reported to harbour tumour suppressor genes (TSGs) which are very likely to be involved in the development of colon, lung, bladder and hepatocellular carcinomas. In addition, the c-myc proto-oncogene which is located on the 8q arm, has been found to be overexpressed in SCCHN. In the present study we have investigated the incidence of loss of heterozygosity (LOH) in chromosome 8 in 37 tumour specimens of squamous cell carcinomas of the head and neck (SCCHN), using a bank of 11 polymorphic microsatellite markers. The aim of this work was to assess whether there was an 8p TSG(s) in SCCHN, as reported in other tumours and also to investigate whether other areas of chromosome 8 exhibit a high LOH. A relatively high incidence of LOH was found for the markers D8S87 (29%) on 8p12 and ANK1 (20%) on 8p21.2-p11. These two markers are located in the area in which TSG(s) for other cancers have been previously described. When the data on D8S87 and ANK1 were analyzed together it was found that 13/35 (37%) of the SCCHN specimens had a loss at one or other of these markers, thus indicating that a putative TSG(s) in this region may play a role in the development of the SCCHN. No correlation was found between the LOH data and any of the clinicopathological parameters. We also investigated the incidence of c-myc amplification in 144 SCCHN specimens but only 4% were found to have an amplified c-myc allele, thus indicating that the overexpression of c-myc in SCCHN was not the result of gene amplification. 相似文献
49.
The acute vascular response in bone to surgical trauma was investigated utilizing a sheep model. Blood flow and distribution were determined using two methods; perfusion of the vasculature with an intravascular vital dye (Disulphine blue) prior to euthanasia and by radionuclide angiography (RNA) before and after each surgical intervention. The pattern of Disulphine blue distribution provided a good indication of local perfuslon and response to surgical trauma (drilling holes). Radionuclide angiography provided a dynamic image of the vascular response to surgical trauma. The generation of time activity curves of the first pass of radionuclide bolus enabled calculation of the relative blood flow through selected regions.
For both techniques areas of ischaemia were apparent which were directly related to the location of screw holes. We conclude that factors other than bone plate contact influence the ischaemia that develops in bone subsequent to the application of bone plates. 相似文献
50.
Shields PL Field J Rawlings J Kendall J Allison SP 《Clinical nutrition (Edinburgh, Scotland)》1996,15(2):64-68
Although there are several published audits of long-term home parenteral nutrition for chronic gastrointestinal failure, there is little data concerning the long-term outcome following prolonged in-patient parenteral nutrition for an episode of acute gastrointestinal failure. Between 1983 and 1 July 1993, 162 patients received total parenteral nutrition (TPN) in our unit for acute gastrointestinal failure for a total of 4997 patient days and using 192 central venous catheters. Over the 10 years there were 11 mechanical complications resulting in one death. Although the overall catheter infection rate was 5.7%, in the last 4 years it was 0%, associated with a reduction in the frequency of site dressing and change of giving set from three times to once weekly. All patients had lost more than 10% of their body weight before TPN. In the non-malignant group, fed for more than 21 days (mean 50 days), the 10-year survival was 74% at a cost of 4723 pounds sterling per year of life saved. In the malignant group, the 5-year survival was 27% at a cost of 8351 pounds sterling per year of life saved. These costs compare favourably with other technologies, such as dialysis for acute renal failure. Better patient selection, fewer complications and lower costs are obtained when this treatment is carried out by an expert team. 相似文献