全文获取类型
收费全文 | 883篇 |
免费 | 94篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 43篇 |
妇产科学 | 2篇 |
基础医学 | 161篇 |
口腔科学 | 14篇 |
临床医学 | 113篇 |
内科学 | 272篇 |
皮肤病学 | 16篇 |
神经病学 | 53篇 |
特种医学 | 151篇 |
外科学 | 26篇 |
综合类 | 17篇 |
一般理论 | 1篇 |
预防医学 | 38篇 |
药学 | 56篇 |
肿瘤学 | 59篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2016年 | 4篇 |
2015年 | 13篇 |
2014年 | 11篇 |
2013年 | 18篇 |
2012年 | 23篇 |
2011年 | 27篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 32篇 |
2007年 | 52篇 |
2006年 | 17篇 |
2005年 | 20篇 |
2004年 | 21篇 |
2003年 | 19篇 |
2002年 | 23篇 |
2001年 | 22篇 |
2000年 | 29篇 |
1999年 | 33篇 |
1998年 | 41篇 |
1997年 | 54篇 |
1996年 | 42篇 |
1995年 | 31篇 |
1994年 | 35篇 |
1993年 | 31篇 |
1992年 | 40篇 |
1991年 | 36篇 |
1990年 | 29篇 |
1989年 | 35篇 |
1988年 | 37篇 |
1987年 | 20篇 |
1986年 | 32篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 15篇 |
1982年 | 9篇 |
1981年 | 11篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 12篇 |
1977年 | 15篇 |
1976年 | 14篇 |
1975年 | 5篇 |
1974年 | 2篇 |
1973年 | 6篇 |
1972年 | 5篇 |
1970年 | 4篇 |
排序方式: 共有1023条查询结果,搜索用时 15 毫秒
1.
2.
3.
K. F. Tait J. E. Collins J. M. Heward I. Eaves H. Snook J. A. Franklyn A. H. Barnett J. A. Todd M. Maranian A. Compston S. Sawcer S. C. L. Gough 《Diabetic medicine》2004,21(3):267-270
Aims The Type 1 diabetes susceptibility locus, IDDM2, has been mapped to a variable number of tandem repeats (VNTR) region 5′ upstream of the insulin (INS) and insulin‐like growth factor (IGF2) genes on chromosome 11p15. The function of the VNTR is uncertain; however, it may influence the thymic expression of the insulin gene and affect the development of immune self‐tolerance. The aim of this study was to investigate whether the INS VNTR region is a Type 1 diabetes‐specific locus or acting as a general autoimmunity gene. Methods We genotyped the INS‐IGF2 VNTR [using the surrogate INS?23 HphI single nucleotide polymorphism (SNP)] in 823 Graves’ disease (GD)/multiple sclerosis (MS) families, 1433 GD/MS patients and 837 healthy control subjects. Results We found no evidence of excess transmission of the allele associated with Type 1 diabetes to individuals affected by GD or MS within the families. Analysis of the case–control dataset showed no genotypic or allelic difference between the two populations. Conclusions These data suggest that the INS‐IGF2 VNTR is acting as a Type 1 diabetes‐specific susceptibility gene rather than as an influence on general autoimmunity. 相似文献
4.
5.
Perforated colorectal neoplasms: correlation of clinical, contrast enema, and CT examinations 总被引:2,自引:0,他引:2
Hulnick DH; Megibow AJ; Balthazar EJ; Gordon RB; Surapenini R; Bosniak MA 《Radiology》1987,164(3):611-615
Results of clinical, contrast enema (CE), and computed tomographic (CT) examinations in 39 patients with perforated colorectal neoplasms were retrospectively reviewed. Twenty patients were toxemic at initial presentation, but in only four patients was the diagnosis of perforated colorectal neoplasm initially suspected clinically. CE study was performed in 22 patients and enabled the diagnosis of perforated neoplasm in 11 cases, neoplasm alone in eight, and neither neoplasm nor perforation in three. CT was performed in 38 patients and enabled the diagnosis of perforated neoplasm in 36; pericolic phlegmon but no mass lesion was evident in two. In 16 patients, CT also demonstrated metastatic disease. Because of its reliability in establishing the diagnosis and staging the extent of the inflammatory and neoplastic disease, CT is indicated in cases of suspected or proved perforated colorectal neoplasm and in cases in which CE study findings are indeterminate or suggestive of perforated neoplasm. 相似文献
6.
7.
Unregulated proliferation of primitive neoplastic progenitor cells in long-term polycythemia vera marrow cultures 总被引:2,自引:2,他引:0
下载免费PDF全文
![点击此处可从《The Journal of clinical investigation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Marrow cells from seven untreated patients with polycythemia vera (PV) were used to initiate standard single inoculum long-term marrow cultures. The numbers, erythropoietin independence, and cycling behavior of all detectable classes of erythroid, granulopoietic, and multilineage progenitors were then evaluated and the results obtained compared with preculture values. Time course studies showed that the long-term marrow culture system supports the continuous proliferation of primitive neoplastic progenitor cells from PV patients for many weeks. However, these progenitors fail to respond to signals from the adherent layer that return their counterparts in normal long-term marrow cultures to a quiescent state 5-7 d after each medium change. This abnormal cycling behavior of PV cells in the long-term culture system appears to mimic that operative in vivo, where primitive hemopoietic progenitors are also in a continuous state of turnover, in contrast to similar primitive progenitor compartments in normal individuals, which are quiescent. The long-term marrow culture system thus offers new possibilities for the further analysis of abnormal cellular and molecular mechanisms underlying clonal expansion at the stem cell level in PV. 相似文献
8.
9.
10.
Coralline hydroxyapatite bone graft substitutes: preliminary report of radiographic evaluation 总被引:1,自引:0,他引:1
A new bone graft substitute made by conversion of the calcium carbonate exoskeleton of reef-building sea coral into hydroxyapatite has recently become clinically available. The normal radiographic appearance of two forms of this material is described. In the immediate postoperative period, the exoskeletal architecture of these implants is readily appreciated. With graft incorporation over the ensuing months, their intrinsic structure is gradually lost in association with poor marginal definition. Evolving radiographic findings reflect the biocompatible nature of these implants, which provides the potential for ingrowth of native bone with preservation of the coralline scaffold, resulting in enhanced biomechanical properties. 相似文献