首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   366篇
  免费   38篇
耳鼻咽喉   1篇
儿科学   14篇
妇产科学   17篇
基础医学   61篇
临床医学   53篇
内科学   84篇
皮肤病学   5篇
神经病学   27篇
特种医学   5篇
外科学   36篇
综合类   2篇
预防医学   48篇
眼科学   4篇
药学   24篇
肿瘤学   23篇
  2023年   4篇
  2022年   6篇
  2021年   14篇
  2020年   15篇
  2019年   14篇
  2018年   15篇
  2017年   9篇
  2016年   15篇
  2015年   6篇
  2014年   15篇
  2013年   32篇
  2012年   28篇
  2011年   28篇
  2010年   15篇
  2009年   8篇
  2008年   24篇
  2007年   22篇
  2006年   19篇
  2005年   17篇
  2004年   17篇
  2003年   19篇
  2002年   7篇
  2001年   2篇
  1999年   2篇
  1998年   2篇
  1997年   2篇
  1991年   2篇
  1990年   2篇
  1987年   2篇
  1986年   2篇
  1983年   3篇
  1981年   2篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1972年   1篇
  1971年   3篇
  1970年   1篇
  1969年   2篇
  1968年   1篇
  1967年   1篇
  1966年   3篇
  1964年   2篇
  1962年   2篇
  1957年   1篇
  1955年   1篇
  1954年   1篇
  1949年   3篇
  1945年   1篇
  1931年   2篇
排序方式: 共有404条查询结果,搜索用时 62 毫秒
1.
Background Familial partial lipodystrophy (FPLD) is a monogenic form of diabetes characterised by a dominantly inherited disorder of adipose tissue associated with the loss of subcutaneous fat from the limbs and trunk, with excess fat deposited around the face and neck. The lipodystrophy causes severe insulin resistance, resulting in acanthosis nigricans, diabetes, dyslipidaemia, and increased risk of cardiovascular disease. Preliminary results from animals and man suggest that increasing subcutaneous fat by treatment with thiazolidinediones should improve insulin resistance and the associated features of this syndrome. Case report We report a 24-year-old patient with FPLD caused by a mutation in the LMNA gene (R482W) treated with 12 months of rosiglitazone. Subcutaneous fat increased following rosiglitazone treatment as demonstrated by a 29% generalised increase in skin-fold thickness. Leptin levels increased from 5.8 to 11.2 ng/ml. Compared with treatment on Metformin, there was an increase in insulin sensitivity (HOMA S% 17.2–31.6) but no change in glycaemic control. The lipid profile worsened during the follow-up period. Conclusion This initial case suggests that, for modification of cardiovascular risk factors, there are no clear advantages in treating patients with FPLD with rosiglitazone despite increases in subcutaneous adipose tissue. Larger series will be needed to identify moderate beneficial effects and treatment may be more effective in patients with generalised forms of lipodystrophy.  相似文献   
2.
The simian-human immunodeficiency virus (SHIV)/ macaque model for human immunodeficiency virus type 1 has become a useful tool to assess the role of Vpu in lentivirus pathogenesis. In this report, we have mutated the two phosphorylated serine residues of the HIV-1 Vpu to glycine residues and have reconstructed a SHIV expressing this nonphosphorylated Vpu (SHIV(S52,56G)). Expression studies revealed that this protein was localized to the same intracellular compartment as wild-type Vpu. To determine if this virus was pathogenic, four pig-tailed macaques were inoculated with SHIV(S52,56G) and virus burdens and circulating CD4(+) T cells monitored up to 1 year. Our results indicate that SHIV(S52,56G) caused rapid loss in the circulating CD4(+) T cells within 3 weeks of inoculation in one macaque (CC8X), while the other three macaques developed no or gradual numbers of CD4(+) T cells and a wasting syndrome. Histological examination of tissues revealed that macaque CC8X had lesions in lymphoid tissues (spleen, lymph nodes, and thymus) that were typical for macaques inoculated with pathogenic parental SHIV(KU-1bMC33) and had no lesions within the CNS. To rule out that macaque CC8X had selected for a virus in which there was reversion of the glycine residues at positions 52 and 56 to serine residues and/or compensating mutations occurred in other genes associated with CD4 down-regulation, sequence analysis was performed on amplified vpu sequences isolated from PBMC and from several lymphoid tissues at necropsy. Sequence analysis revealed a reversion of the glycine residues back to serine residues in this macaque. The other macaques maintained low virus burdens, with one macaque (P003) developing a wasting syndrome between months 9 and 11. Histological examination of tissues from this macaque revealed a thymus with severe atrophy that was similar to that of a previously reported macaque inoculated with a SHIV lacking vpu (Virology 293, 2002, 252). Sequence analysis revealed no reversion of the glycine residues in the vpu sequences isolated from this macaque. These results contrast with those from four macaques inoculated with the parental pathogenic SHIV(KU-1bMC33), all of which developed severe CD4(+) T cell loss within 1 month after inoculation. Taken together, these results indicate that casein kinase II phosphorylation sites of Vpu contributes to the pathogenicity of the SHIV(KU-1bMC33) and suggest that the SHIV(KU-1bMC33)/pig-tailed macaque model will be useful in analyzing amino acids/domains of Vpu that contribute to the pathogenesis of HIV-1.  相似文献   
3.
Summary The membrane potential of smooth muscle cells in the circular layer of the guinea pig ileum was recorded using intracellular electrodes. Transmural stimulation, in the presence of atropine, caused a transient hyperpolarization, an inhibitory junction potential (IJP). IJP's are thought to result from the action of transmitter released from intramural inhibitory nerves. It has been reported that, in the guinea pig jejunum, the amplitude of the IJP resulting from field stimulation is not altered by changes in the calcium and magnesium ion concentration in the bathing solution. Experiments reported here have shown that the IJP amplitude decreased markedly on reducing the calcium ion concentration and or increasing the magnesium ion concentration. Indirect evidence is presented suggesting that the decrease in amplitude of the IJP is due to a decrease in the amount of transmitter released.  相似文献   
4.
Archives of Sexual Behavior - Although men who have sex with men (MSM) within rural communities are disproportionately impacted by HIV, limited HIV research and programmatic resources are directed...  相似文献   
5.
OBJECTIVE: The purpose of this study was to examine the association between intensive care unit nurse (ICU) staffing and the likelihood of complications for patients undergoing abdominal aortic surgery. DESIGN: The study is a retrospective review of hospital discharge data linked to data on ICU organizational characteristics. SETTING: Research took place in ICUs in non-federal, short-stay hospitals in Maryland. PATIENTS: Study included 2606 patients undergoing abdominal aortic surgery in Maryland between January 1994 and December 1996. Outcome Measures: Outcome measures included cardiac, respiratory, and other complications. RESULTS: Cardiac complications occurred in 13% of patients, respiratory complications occurred in 30%, and other complications occurred in 8% of patients. Multiple logistic regression revealed a statistically significant increased likelihood of respiratory complications (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.50-3.60) in abdominal aortic surgery patients cared for in ICUs with low- versus high-intensity nurse staffing, an increased likelihood of cardiac complications (OR, 1.78; CI, 1.16-2.72) and other complications (OR, 1.74; CI, 1.15-2.63) in ICUs with medium- versus high-intensity nurse staffing, after controlling for patient and organizational characteristics. CONCLUSIONS: Within the range of ICU nurse staffing levels present in Maryland hospitals, decreased nurse staffing was significantly associated with an increased risk of complications in patients undergoing abdominal aortic surgery.  相似文献   
6.
7.
8.
9.
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号