全文获取类型
收费全文 | 925篇 |
免费 | 51篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 40篇 |
妇产科学 | 5篇 |
基础医学 | 104篇 |
口腔科学 | 44篇 |
临床医学 | 93篇 |
内科学 | 208篇 |
皮肤病学 | 40篇 |
神经病学 | 32篇 |
特种医学 | 153篇 |
外国民族医学 | 1篇 |
外科学 | 68篇 |
综合类 | 45篇 |
预防医学 | 69篇 |
眼科学 | 5篇 |
药学 | 45篇 |
中国医学 | 1篇 |
肿瘤学 | 27篇 |
出版年
2023年 | 3篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 12篇 |
2018年 | 13篇 |
2017年 | 15篇 |
2016年 | 16篇 |
2015年 | 31篇 |
2014年 | 17篇 |
2013年 | 31篇 |
2012年 | 29篇 |
2011年 | 31篇 |
2010年 | 38篇 |
2009年 | 48篇 |
2008年 | 33篇 |
2007年 | 23篇 |
2006年 | 23篇 |
2005年 | 16篇 |
2004年 | 34篇 |
2003年 | 23篇 |
2002年 | 13篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 18篇 |
1998年 | 54篇 |
1997年 | 62篇 |
1996年 | 56篇 |
1995年 | 42篇 |
1994年 | 40篇 |
1993年 | 37篇 |
1992年 | 7篇 |
1991年 | 11篇 |
1990年 | 16篇 |
1989年 | 14篇 |
1988年 | 22篇 |
1987年 | 23篇 |
1986年 | 21篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 8篇 |
1982年 | 18篇 |
1981年 | 3篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 2篇 |
1968年 | 3篇 |
1959年 | 2篇 |
排序方式: 共有985条查询结果,搜索用时 0 毫秒
981.
Long-term follow-up of blood donors with indeterminate human immunodeficiency virus type 1 results on Western blot 总被引:3,自引:0,他引:3
JB Jackson ; MR Hanson ; GM Johnson ; TG Spahlinger ; HF Polesky ; RJ Bowman 《Transfusion》1995,35(2):98-102
BACKGROUND: At present, tens of thousands of United States blood donors who are at low risk for human immunodeficiency virus type 1 (HIV-1) infection are indefinitely deferred. These persons are repeatably reactive for HIV-1 antibody in enzyme immunoassay (EIA) and are indeterminate in Western blot. STUDY DESIGN AND METHODS: To determine the significance and persistence of anti-HIV-1 reactivity in plasma from volunteer blood donors with HIV-1-indeterminate Western blots, 66 donors were retested for HIV-1 antibody by the same manufacturers' EIA and Western blot 5 to 7 years after the initial Western blot. In addition, donors' peripheral blood mononuclear cells were tested by polymerase chain reaction (PCR) for HIV-1 DNA gag sequences. RESULTS: Thirty-five (53%) of 66 donors were still repeatedly reactive for HIV-1 on EIA and indeterminate on Western blot, 23 (35%) were negative on EIA and indeterminate on Western blot, 7 (11%) were negative in EIA and Western blot, and 1 (2%) was repeatedly reactive on EIA and negative on Western blot. Donors with persistently indeterminate Western blots had a band pattern nearly identical to that on the original Western blot. No donor was positive in Western blot, p24 antigen, or PCR testing. No donor had signs or symptoms of HIV-1 infection. CONCLUSION: Long-term follow-up of Western blot-indeterminate blood donors does not reveal evidence of HIV-infection. A mechanism to return these donors to the donor pool should be considered. 相似文献
982.
Ontogeny of B-lymphocyte function. III. In vivo and in vitro studies on the ease of tolerance induction in B lymphocytes from fetal, neonatal, and adult mice
下载免费PDF全文
![点击此处可从《The Journal of experimental medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The ease of tolerance induction in B lymphocytes from fetal, neonatal, and adult mice was studied in vivo, in a cell transfer system, and in vitro. Three different tolerogens were used: ultracentrifuged BGG, DNP(6)-D-GL, and ultracentrifuged DNP(22)-BGG. Irradiated thymectomized mice were reconstituted with B cells from fetal or neonatal liver or adult spleen or bone marrow. The mice were injected with tolerogen 1 day later. They were given normal thymus cells and challenged with either BGG or DNP(44)-BGG between 4 and 14 days after tolerance induction. With BGG no difference in ease of B-cell tolerance induction was observed in mice reconstituted with B cells from 17-day fetal liver, neonatal liver, 8- day-old spleen, adult spleen, or adult bone marrow. B cells from 14-day fetal donors are relatively resistant to tolerance induction. In contrast, with DNP(6)-D-GL and DNP(22)-BGG B cells from neonatal donors were clearly more susceptible to tolerance induction than were B cells from adult donors. Comparable results were obtained in studies on tolerance induction in vitro. Neonatal B cells were more susceptible than adult B cells to tolerance induction upon culture with DNP(6)-D-GL or DNP(22)-BGG. However, neonatal and adult B cells were identical with respect to ease of tolerance induction in vitro with deaggregated BGG. The results suggest that there are multiple mechanisms for B-cell tolerance induction. Immature B cells appear to be more susceptible to tolerance induction by some mechanisms but not by others. It is suggested that immature B cells are more susceptible to tolerance induction with moderately polyvalent antigens such as hapten-carrier conjugates. With antigens like BGG which do not haverepeated epitopes no difference between mature and fetal B cells in regard to ease of tolerance induction is observed. These observations raise questions about the importance of relative ease of tolerance induction in immature B cells as a mechanism controlling the normal induction of self tolerance. 相似文献
983.
Kyeezu Kim Brian T. Joyce Yinan Zheng Pamela J. Schreiner David R. Jacobs Jr. Janet M. Catov James M. Shikany Mercedes R. Carnethon Philip Greenland Linda V. Van Horn Norrina B. Allen Donald M. Lloyd-Jones Erica P. Gunderson Lifang Hou 《Diabetes》2021,70(6):1404
DNA methylation (DNAm)-based biological age (epigenetic age) has been suggested as a useful biomarker of age-related conditions including type 2 diabetes (T2D), and its newest iterations (GrimAge measurements) have shown early promise. In this study, we explored the association between epigenetic age and incident T2D in the context of their relationships with obesity. A total of 1,057 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study were included in the current analyses. We stratified the participants into three groups: normal weight, overweight, and obese. A 1-year increase of GrimAge was associated with higher 10-year (study years 15–25) incidence of T2D (odds ratio [OR] 1.06, 95% CI 1.01–1.11). GrimAge acceleration, which represents the deviation of GrimAge from chronological age, was derived from the residuals of a model of GrimAge and chronological age, and any GrimAge acceleration (positive GrimAA: having GrimAge older than chronological age) was associated with significantly higher odds of 10-year incidence of T2D in obese participants (OR 2.57, 95% CI 1.61–4.11). Cumulative obesity was estimated by years since obesity onset, and GrimAge partially mediated the statistical association between cumulative obesity and incident diabetes or prediabetes (proportion mediated = 8.0%). In conclusion, both older and accelerated GrimAge were associated with higher risk of T2D, particularly among obese participants. GrimAge also statistically mediated the associations between cumulative obesity and T2D. Our findings suggest that epigenetic age measurements with DNAm can potentially be used as a risk factor or biomarker associated with T2D development. 相似文献
984.