全文获取类型
收费全文 | 420篇 |
免费 | 21篇 |
国内免费 | 16篇 |
专业分类
儿科学 | 37篇 |
妇产科学 | 13篇 |
基础医学 | 48篇 |
口腔科学 | 17篇 |
临床医学 | 44篇 |
内科学 | 54篇 |
皮肤病学 | 13篇 |
神经病学 | 10篇 |
特种医学 | 75篇 |
外科学 | 33篇 |
综合类 | 14篇 |
预防医学 | 17篇 |
眼科学 | 15篇 |
药学 | 39篇 |
中国医学 | 1篇 |
肿瘤学 | 27篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 7篇 |
2014年 | 19篇 |
2013年 | 24篇 |
2012年 | 8篇 |
2011年 | 14篇 |
2010年 | 33篇 |
2009年 | 28篇 |
2008年 | 7篇 |
2007年 | 20篇 |
2006年 | 10篇 |
2005年 | 11篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 13篇 |
1998年 | 33篇 |
1997年 | 23篇 |
1996年 | 16篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1993年 | 11篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 9篇 |
1978年 | 7篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1959年 | 1篇 |
1958年 | 2篇 |
1957年 | 1篇 |
1955年 | 1篇 |
1954年 | 2篇 |
1949年 | 2篇 |
排序方式: 共有457条查询结果,搜索用时 15 毫秒
61.
B Lönnerdal N Zavaleta L Kusunoki CF Lanata JM Peerson KH Brown 《Acta paediatrica (Oslo, Norway : 1992)》1996,85(5):537-542
In developing countries, maternal infections during lactation are common. In this study, we evaluated the effect of acute maternal postpartum infection on the composition of colostrum and early milk with special emphasis on milk proteins and trace elements. The study was carried out in two maternity hospitals in Lima, Peru. Subjects were normally nourished women (body mass index (BMI) > 20.0) who intended to exclusively breastfeed their child and who had fever and clinical symptoms of infection within the first 48 h postpartum ( n = 34). Non-ill women of similar characteristics were selected as controls ( n = 23). Blood and milk samples were taken on days 1 and 14 postpartum. An acute phase response was confirmed by significantly increased serum levels of C-reactive protein in infected women. Serum zinc levels increased significantly from day 1 to day 14, but were not affected by infection. Serum copper levels were significantly higher in ill women than in non-ill women on day 1. All participating women were breastfeeding on day 14. Whey protein levels, the whey/casein ratio and total protein levels decreased significantly with time, but were not affected by infection. There were no differences in milk iron or copper levels with time or infection. Milk zinc levels decreased significantly with time, but were not affected by infection. Maternal infection during the early postpartum period does not appear to adversely affect the initiation of lactation or milk protein and trace element contents. 相似文献
62.
63.
64.
65.
66.
Possible effect of secretor locus on plasma concentration of factor VIII and von Willebrand factor 总被引:2,自引:1,他引:2
A significant fraction (30%) of the genetically determined variance in plasma concentration of the von Willebrand factor antigen (vWf:Ag) has been shown to be related to ABH determinants. Individuals with blood group O, who have the highest amounts of blood group H substance, have the lowest concentration of vWf:Ag. The Lewis substances, Le(a) and Le(b), are biochemically closely related to the ABH substances as both can be produced from the same precursor substance. We studied the effect of the presence of the Lewis antigens on the plasma concentration of vWf:Ag and factor VIII antigen (VIII:Ag) in 323 individuals of different ABO groups from a series of twins and in 58 blood donors of blood group O. Among persons belonging to blood group O, those with the Le(a) antigen had a higher concentration of both vWf:Ag and VIII:Ag than individuals lacking Le(a). Le(a+b-) people are nonsecretors and Le(a-b+) people are secretors of ABH substance. Thus, the lowest concentration of vWf:Ag and VIII:Ag was found in group O secretors. The effect is most likely due to an effect of the secretor locus. This finding may be of importance for the detection of carriers of hemophilia A and for the diagnosis of type I von Willebrand disease. 相似文献
67.
Andy KH Lim 《World journal of gastroenterology : WJG》2020,26(10):1020-1028
Rhabdomyolysis is a syndrome of skeletal muscle injury with release of cellular constituents such as potassium,phosphate,urate and intracellular proteins such as myoglobin into the circulation,which may cause complications including acute kidney injury,electrolyte disturbance and cardiac instability.Abnormal liver function tests are frequently observed in cases of severe rhabdomyolysis.Typically,there is an increase in serum aminotransferases,namely aspartate aminotransferase and alanine aminotransferase.This raises the question of liver injury and often triggers a pathway of investigation which may lead to a liver biopsy.However,muscle can also be a source of the increased aminotransferase activity.This review discusses the dilemma of finding abnormal liver function tests in the setting of muscle injury and the potential implications of such an association.It delves into some of the clinical and experimental evidence for correlating muscle injury to raised aminotransferases,and discusses pathophysiological mechanisms such as oxidative stress which may cause actual liver injury.Serum aminotransferases lack tissue specificity to allow clinicians to distinguish primary liver injury from muscle injury.This review also explores potential approaches to improve the accuracy of our diagnostic tools,so that excessive or unnecessary liver investigations can be avoided. 相似文献
68.
69.
Decreased expression of phospholipase C-beta 2 isozyme in human platelets with impaired function 总被引:4,自引:4,他引:4
Platelets from a patient with a mild inherited bleeding disorder and abnormal platelet aggregation and secretion show reduced generation of inositol 1,4,5-trisphosphate, mobilization of intracellular Ca2+, and phosphorylation of pleckstrin in response to several G protein mediated agonists, suggesting a possible defect at the level of phospholipase C (PLC) activation (see accompanying report). A procedure was developed that allows quantitation of platelet PLC isozymes. After fractionation of platelet extracts by high-performance liquid chromatography, 7 out of 10 known PLC isoforms were detected by immunoblot analysis. The amount of these isoforms in normal platelets decreased in the order PLC- gamma 2 > PLC-beta 2 > PLC-beta 3 > PLC-beta 1 > PLC-gamma 1 > PLC- delta 1 > PLC-beta 4. Compared with normal platelets, platelets from the patient contained approximately one-third the amount of PLC-beta 2, whereas PLC-beta 4 was increased threefold. These results suggest that the impaired platelet function in the patient in response to multiple G protein mediated agonists is attributable to a deficiency of PLC-beta 2. They document for the first time a specific PLC isozyme deficiency in human platelets and provide an unique opportunity to understand the role of different PLC isozymes in normal platelet function. 相似文献
70.
Devin R. Halleran Alejandra Vilanova-Sanchez Rebecca M. Rentea Mana H. Vriesman Tassiana Maloof Peter L. Lu Amanda Onwuka Laura Weaver Karla KH Vaz Desale Yacob Carlo Di Lorenzo Marc A. Levitt Richard J. Wood 《Journal of pediatric surgery》2019,54(1):123-128