全文获取类型
收费全文 | 593篇 |
免费 | 56篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 40篇 |
妇产科学 | 8篇 |
基础医学 | 101篇 |
口腔科学 | 25篇 |
临床医学 | 73篇 |
内科学 | 148篇 |
皮肤病学 | 9篇 |
神经病学 | 18篇 |
特种医学 | 38篇 |
外科学 | 71篇 |
综合类 | 19篇 |
预防医学 | 31篇 |
眼科学 | 41篇 |
药学 | 19篇 |
中国医学 | 1篇 |
肿瘤学 | 22篇 |
出版年
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 14篇 |
2013年 | 20篇 |
2012年 | 20篇 |
2011年 | 16篇 |
2010年 | 15篇 |
2009年 | 18篇 |
2008年 | 16篇 |
2007年 | 24篇 |
2006年 | 10篇 |
2005年 | 18篇 |
2004年 | 12篇 |
2003年 | 5篇 |
2002年 | 15篇 |
2001年 | 19篇 |
2000年 | 20篇 |
1999年 | 14篇 |
1998年 | 24篇 |
1997年 | 24篇 |
1996年 | 22篇 |
1995年 | 18篇 |
1994年 | 17篇 |
1993年 | 11篇 |
1992年 | 18篇 |
1991年 | 16篇 |
1990年 | 14篇 |
1989年 | 15篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 20篇 |
1985年 | 26篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1981年 | 5篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 7篇 |
1974年 | 9篇 |
1972年 | 4篇 |
1971年 | 6篇 |
1970年 | 4篇 |
1969年 | 5篇 |
排序方式: 共有671条查询结果,搜索用时 0 毫秒
51.
We have attempted to localize immunohistochemically phosphatidylinositol-4,5-bisphosphate (PIP2) in rat lens tissue using affinity purified rabbit anti-PIP2 antibodies. Evidence indicates that PIP2 is localized to the lens epithelial cells but appears to be absent from the lens fiber cells. 相似文献
52.
53.
Gsta Samuelson 《Acta paediatrica (Oslo, Norway : 1992)》2002,91(1):vi-vi
Book Reviewed in this article:
Preedy V, Grimble G, Watson R. Nutrition in the Infant. Problems and Practical Procedures . London: Greenwich Medical Media Ltd, 2001. 447 pp. Price GBP 85. ISBN 1 900151626. 相似文献
Preedy V, Grimble G, Watson R. Nutrition in the Infant. Problems and Practical Procedures . London: Greenwich Medical Media Ltd, 2001. 447 pp. Price GBP 85. ISBN 1 900151626. 相似文献
54.
R L Zhang D A Samuelson Z G Zhang V N Reddy B S Shastry 《Investigative ophthalmology & visual science》1991,32(9):2662-2665
The congenital hereditary cataracts and microphthalmia in the miniature schnauzer dog are inherited by an autosomal recessive mode. To understand the genetic basis of these diseases, the authors purified and analyzed leukocyte deoxyribonucleic acid (DNA) from affected and normal animals using a candidate gene approach. Because the genes that encode the lens-specific proteins, specifically, alpha, beta, and gamma crystallins and the membrane protein (MP26), are known to maintain the structure and function of the lens, the authors used complimentary DNA (cDNA) fragments that corresponded to the above genes to search for the mutations at their loci in the affected animals. They found no evidence of the gene deletion and rearrangement in any of the five loci. In addition, the hybridizable sequences of the dog DNA to the specific probes for the human chromosome 4 and 18 loci, which are reported to be involved in the abnormality of the human eye, seem to be unaffected. These data support the notion that the hereditary cataracts and microphthalmia in the dog may be associated with genes other than those reported for several animal systems. 相似文献
55.
56.
WH Belloso LC Orellana B Grinsztejn JS Madero A La Rosa VG Veloso J Sanchez R Ismerio Moreira B Crabtree‐Ramirez O Garcia Messina MB Lasala J Peinado MH Losso 《HIV medicine》2010,11(9):554-564
Objective
Acquired immune deficiency appears to be associated with serious non‐AIDS (SNA)‐defining conditions such as cardiovascular disease, liver and renal insufficiency and non‐AIDS‐related malignancies. We analysed the incidence of, and factors associated with, several SNA events in the LATINA retrospective cohort.Materials and methods
Cases of SNA events were recorded among cohort patients. Three controls were selected for each case from cohort members at risk. Conditional logistic models were fitted to estimate the effect of traditional risk factors as well as HIV‐associated factors on non‐AIDS‐defining conditions.Results
Among 6007 patients in follow‐up, 130 had an SNA event (0.86 events/100 person‐years of follow‐up) and were defined as cases (40 with cardiovascular events, 54 with serious liver failure, 35 with non‐AIDS‐defining malignancies and two with renal insufficiency). Risk factors such as diabetes, hepatitis B and C virus coinfections and alcohol abuse showed an association with events, as expected. The last recorded CD4 T‐cell count prior to index date (P=0.0056, with an average difference of more than 100 cells/μL) and area under the CD4 cell curve in the year previous to index date (P=0.0081) were significantly lower in cases than in controls. CD4 cell count at index date was significantly associated with the outcome after adjusting for risk factors.Conclusions
The incidence and type of SNA events found in this Latin American cohort are similar to those reported in other regions. We found a significant association between immune deficiency and the risk of SNA events, even in patients under antiretroviral treatment. 相似文献57.
58.
Objective:To investigate the wound healing properly of Napoleona vogelii leaf extract in folkloric medicine.Methods:Roth sexes of adult albino rats(n=25) were used in this study and another group(n=30) were subjected to acute toxicity test(LD_(50)) of the plant extract.For the LD_(50),three randomized groups of 5 rats were first treated with 10,100,1 000 mg/kg body weight(bw),orally.This w as followed by a second treatment of 1500,3000,and 5 000 mg/kg bw of the leaf extract with continual monitoring of the animals for mortality or non-mortality.Incision wounds(1.3cm) were created on the skin of five groups of 5 rals using surgical blade under anesthesia.The first group was topically treated with petroleum jelly alone,group 2 was topically applied 400 mg/mL w/v of the reference drug,Neobaein,while group 3-5 were topically treated with 5-50 mg/mL w/v of the plant extract,respectively.Results:The percentage yield of the extract was 49.80%w/w dry matter.The phytochemical analysis revealed several bioactive constituents including glycosides,tannins,alkaloids,perpenoids.saponins,steroids,proteins,and carbohydrates.The LD_(50) was beyond our experimental limit and was not determined.Increased concentrations(5,20,and 50mg/mL w/v) of the extract had significant(ANOVA,P0.05) healing effect on the incision wounds giving rise to 125%-140% while treatmentawith Neobacin resulted in 150% healing effect on the third treatment regimen compared to the control(100%).Conclusions:These data indicate that Napoleona vogelii leaf extract contains potent bioactive compounds containing wound healing activity,substantiating its use as a wound healer in folkloric medicine. 相似文献
59.
60.
Paul A. Samuelson 《Proceedings of the National Academy of Sciences of the United States of America》1974,71(8):3041-3044
The conservative model of Volterra for more-than-two predator-prey species is shown to be generated as extremals that minimize a definable Lagrange-Hamilton integral involving half the species and their rates of change. This least-action formulation differs from that derived two generations ago by Volterra, since his involves twice the number of phase variables and it employs as variables the cumulative integrals of the numbers of each species that have ever lived. The present result extends the variational, teleological formulations found a decade ago by the author to the more-than-two species case. The present result is anything but surprising, in view of the works by Kerner, Montroll, and others which apply Gibbs' statistical mechanics to the all-but-canonical equations of the standard Volterra model. By a globally linear transformation of coordinates, the Volterra equations are here converted into a completely canonical system isomorphic with the classical mechanics models of Newton, Lagrange, Hamilton, Jacobi, Boltzmann, Gibbs, Poincaré, and G. D. Birkhoff. The conservative nature of the Lotka-Volterra model, whatever its realism, is a crucially necessary condition for the applicability of the variational formalisms, microscopically and macroscopically. 相似文献