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   428篇
  免费   50篇
  国内免费   5篇
耳鼻咽喉   1篇
儿科学   49篇
妇产科学   15篇
基础医学   100篇
口腔科学   11篇
临床医学   57篇
内科学   119篇
皮肤病学   6篇
神经病学   10篇
特种医学   45篇
外科学   14篇
综合类   4篇
预防医学   10篇
眼科学   8篇
药学   22篇
肿瘤学   12篇
  2021年   5篇
  2020年   2篇
  2019年   2篇
  2018年   2篇
  2015年   7篇
  2014年   8篇
  2013年   8篇
  2012年   12篇
  2011年   18篇
  2010年   16篇
  2009年   9篇
  2008年   18篇
  2007年   17篇
  2006年   22篇
  2005年   21篇
  2004年   12篇
  2003年   12篇
  2002年   12篇
  2001年   18篇
  2000年   9篇
  1999年   23篇
  1998年   15篇
  1997年   9篇
  1996年   20篇
  1995年   10篇
  1994年   9篇
  1993年   11篇
  1992年   8篇
  1991年   9篇
  1990年   11篇
  1989年   4篇
  1988年   9篇
  1987年   8篇
  1986年   8篇
  1985年   7篇
  1984年   8篇
  1983年   9篇
  1982年   11篇
  1981年   6篇
  1980年   8篇
  1979年   6篇
  1978年   7篇
  1977年   15篇
  1976年   6篇
  1975年   3篇
  1974年   2篇
  1972年   2篇
  1971年   4篇
  1969年   1篇
  1965年   1篇
排序方式: 共有483条查询结果,搜索用时 15 毫秒
1.
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis.  相似文献   
2.
3.
Medial border of the perirenal space: CT and anatomic correlation   总被引:11,自引:0,他引:11  
  相似文献   
4.
5.
Circannual variation in lymphocyte subsets, revisited   总被引:2,自引:0,他引:2  
BACKGROUND: Circadian and circannual variations in lymphocyte subsets, especially CD8+ T-lymphocytes, have been reported. This study focuses on CD4+ T-lymphocyte seasonal variation over a 6-year 8-month period. STUDY DESIGN AND METHODS: Lymphocyte subsets were quantitated monthly for four healthy individuals from 1986 through 1992 as part of a flow cytometry quality-control program. RESULTS: In general, there were no significant seasonal changes in the total number of white cells or in total lymphocyte counts. The absolute numbers of CD4+ T-lymphocytes were lowest in summer when the CD8+ T-lymphocytes were highest. Mean CD4+ T-lymphocyte counts were 846, 967, 618, and 695 per microL for Subjects 1 through 4, respectively, in winter and 432, 670, 355, and 766 per microL, respectively, in summer. Two healthy subjects had CD4+ T-lymphocyte counts lower than 300 per microL on one or more occasions during the study period. In three of the four subjects, the percentage of B-lymphocytes in winter was almost double that in summer. In one of the four subjects, no circannual rhythm was observed in these lymphocyte subpopulations. CONCLUSION: The seasonal variation in CD4+ T- lymphocyte counts demonstrated in three healthy individuals over almost 7 years is again of interest in light of renewed consideration of using surrogate tests, such as CD4+ T-lymphocyte counts, to screen for AIDS- like diseases that may be in the blood supply.  相似文献   
6.
The objective of this study was to test the safety of withholding anticoagulant treatment and additional call-back diagnostic testing with ultrasound in patients who have a negative D-dimer at presentation. Patients with signs and symptoms of deep-vein thrombosis who presented to the emergency department after regular hours and on weekends underwent D-dimer testing using the STA-Liatest D-di. In patients with negative D-dimer results, heparin therapy was withheld, and no further diagnostic testing for deep-vein thrombosis was done as part of the initial evaluation. Patients with positive D-dimer results underwent compression ultrasonography. The primary outcome measure was a diagnosis of new symptomatic venous thromboembolism confirmed by diagnostic testing during the 3-month follow-up period. Of the 260 eligible patients, 81 (31%) had a negative D-dimer and 179 (69%) had a positive D-dimer. No patient with a negative D-dimer at presentation had confirmed venous thromboembolism at 3-month follow-up. Three patients died: one by intracranial hemorrhage secondary to cerebrovascular accident; and two deaths of indeterminate cause almost 3 months after entry. The automated assay for D-dimer, the STA-Liatest D-di, seems to provide a simple method with high clinical utility for excluding acute first-episode deep-vein thrombosis in symptomatic patients who present to the emergency room after regular hours.  相似文献   
7.
SP-A is the most abundant, surfactant-associated protein isolated from lung lavage. Genomic blot analysis of total human cellular DNA with SP-A cDNA demonstrated the presence of multiple hybridizing fragments that are not accounted for by available SP-A gene sequences. In this report, we have cloned and characterized human genomic DNA fragments that account for some of the other hybridizing fragments. These clones contain nucleotide sequences that are highly homologous to the fourth intron and fifth exon of the human SP-A gene. Sequences upstream from these SP-A-like sequences are not detectable by Northern blot hybridization of SP-A-expressing cells and the SP-A-like sequences contain premature stop codons, consistent with the interpretation that these clones represent an SP-A pseudogene. Restriction fragments consistent with this pseudogene and the functional SP-A gene are present in a human chromosome 10 genomic library made from a single chromosome, showing that the functional SP-A gene and the pseudogene are syntenic.  相似文献   
8.
A rapid microagglutination test has been developed which can be performed in 30 minutes. Ninety-seven percent of 96 patients diagnosed as having Legionella pneumophila (serogroup 1) infection by indirect immunofluorescence were also detected by the rapid microagglutination test.  相似文献   
9.
10.
Glutathione (GSH), GSH peroxidase (GPX), GSH reductase (GRD), superoxide dismutase (SOD) and catalase-like enzyme activity were quantified in seminal plasma from normozoospermic patients, men with known distal ductal occlusion, proven fathers and male partners of couples receiving in-vitro fertilization (IVF) treatment for both male and female causes. Glutathione was non-detectable (< 2.5 microM) in seminal plasma. None of the enzyme activities per unit volume were lower in semen from vasectomized men, suggesting that they did not originate substantially from the testis or epididymis. The strongest relationships between enzyme activities and accessory gland markers were between zinc and GRD (r = 0.678), SOD (r = 0.602) and GPX (r = 0.548), suggesting a largely prostatic origin of these enzymes. Only weak relationships between accessory gland markers and catalase-like activity suggested a multi-glandular source of this enzyme. There was no relationship between the activity of any of the enzymes in the IVF patients with their fertilization rates in vitro or the establishment of pregnancy after IVF. Nor was there any correlation of enzyme activity with the morphology and percentage of motile spermatozoa in semen or with the percentage motility of spermatozoa immediately after swim-up or after overnight incubation. These findings suggest that the protective enzymes in the seminal plasma are contributed largely by the prostate and little by the epididymis, and that in most cases of IVF, they have no major influence on the outcome.   相似文献   
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