全文获取类型
收费全文 | 439篇 |
免费 | 58篇 |
国内免费 | 8篇 |
专业分类
儿科学 | 33篇 |
妇产科学 | 4篇 |
基础医学 | 51篇 |
口腔科学 | 7篇 |
临床医学 | 40篇 |
内科学 | 130篇 |
皮肤病学 | 3篇 |
神经病学 | 9篇 |
特种医学 | 42篇 |
外科学 | 128篇 |
综合类 | 8篇 |
预防医学 | 26篇 |
眼科学 | 3篇 |
药学 | 8篇 |
肿瘤学 | 13篇 |
出版年
2019年 | 3篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 10篇 |
2014年 | 12篇 |
2013年 | 16篇 |
2012年 | 7篇 |
2011年 | 9篇 |
2010年 | 9篇 |
2009年 | 12篇 |
2008年 | 9篇 |
2007年 | 13篇 |
2006年 | 16篇 |
2005年 | 17篇 |
2004年 | 17篇 |
2003年 | 7篇 |
2002年 | 11篇 |
2001年 | 10篇 |
2000年 | 15篇 |
1999年 | 6篇 |
1998年 | 21篇 |
1997年 | 17篇 |
1996年 | 21篇 |
1995年 | 21篇 |
1994年 | 18篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1990年 | 11篇 |
1989年 | 18篇 |
1988年 | 12篇 |
1987年 | 16篇 |
1986年 | 12篇 |
1985年 | 13篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1970年 | 2篇 |
1968年 | 3篇 |
1966年 | 2篇 |
排序方式: 共有505条查询结果,搜索用时 171 毫秒
1.
2.
Mechanism of long-term degeneration of arterialized vein grafts 总被引:3,自引:0,他引:3
This study examined long-term changes in the morphology and cellular kinetics of rabbit vein grafts transplanted into the carotid artery. Six grafts were studied 1 year after implantation. Although the circumference and thickness of the wall were not different than at 12 weeks, degenerative changes occurred. The endothelial lining of the graft appeared intact, but large segments of the graft surface no longer excluded Evans blue dye, suggesting increased permeability. Collections of red blood cells were noted within the intima. Several grafts had extensive subendothelial fibrin deposits, often associated with foam cells, and evidence of previous hemorrhage, but these changes did not stimulate significant smooth muscle cell proliferation. Increased permeability with entrance of proteins and erythrocytes into the intima may result from increased wall tension or from low shear rates at the wall. Similar changes may lead to atherosclerosis in human vein grafts at late times. 相似文献
3.
4.
Anand N Arora S Clowes M 《世界核心医学期刊文摘》2006,2(5):21-22
目的:前瞻性研究青光眼术中应用丝裂霉素C(MMC)对于结膜滤过泡高危因素如无血管化、经结膜的渗漏(TCO)和滤过泡裂孔的影响。方法:一位观察者对进行了青光眼手术联合MMC的125例连续患者的125只眼进行为期2年的前瞻性研究,这些患者最初都成功地建立了滤过通道。巩膜瓣切开前将MMC置于该区,多数患者MMC0.2g/L持续2min。青光眼手术包括小梁切除术、深巩膜切除术和联合手术。将干燥的荧光素试纸置于滤过泡的无血管区,以观察房水外流[点渗漏(PL)或未流出(TCO)]。 相似文献
5.
Hydrosalpinges adversely affect markers of endometrial receptivity 总被引:22,自引:10,他引:22
Meyer WR; Castelbaum AJ; Somkuti S; Sagoskin AW; Doyle M; Harris JE; Lessey BA 《Human reproduction (Oxford, England)》1997,12(7):1393-1398
While in-vitro fertilization (IVF) was initially developed in women with
tubal factor infertility, recent clinical studies have suggested that the
presence of hydrosalpinges lowers implantation and pregnancy rates. We
postulated that these hydrosalpinges cause impaired endometrial
receptivity. A total of 103 women with hydrosalpinges were prospectively
evaluated, and compared with 55 infertile and 44 fertile controls. All
women had endometrial biopsies during the window of implantation, analysed
by conventional histological criteria, and also stained for three integrin
markers of endometrial receptivity (alpha1beta1, alpha4beta1 and alpha
vbeta3). Women with hydrosalpinges (cases) expressed significantly less of
the alpha vbeta3 integrin compared with controls. There was no difference
in expression of alpha1beta1 or alpha4beta1 among groups. A significantly
greater number of cases had out of phase histology and missing alpha vbeta3
(type I defects) and absent integrin expression despite normal histological
maturation (type II) defects, compared with controls. Of 20 women with
impaired endometrial receptivity who were also biopsied after hydrosalpinx
surgery, 70% demonstrated increased alpha vbeta3 expression. Seventy-seven
percent of type I and 57% of type II defects were corrected
postoperatively. Using markers of endometrial receptivity, this study
demonstrates that inflammatory hydrosalpinges have an adverse effect on
endometrial receptivity, which in some cases may be overcome by surgical
treatment of the hydrosalpinx.
相似文献
6.
bcl-2 transgene expression promotes survival and reduces proliferation of CD3-CD4-CD8- T cell progenitors 总被引:16,自引:0,他引:16
Proliferative expansion and apoptotic cell death play prominent roles in T
cell development. The molecular control of cell cycle progression and
apoptosis appear to be inter-connected since the Bcl-2 protein can inhibit
apoptosis and slow cell cycle progression in cortical thymocytes and mature
T cells, particularly during the transition from the quiescent state into
the cell cycle. Here the impact of bcl-2 transgene expression on
CD3-CD4-CD8- T cell progenitors was assessed. Bcl-2 enhanced the survival
of these progenitors at all of the four major differentiation stages, CD25-
CD44+ (pro-T1), CD25 + CD44+ (pro- T2), CD25 + CD44- (pro-T3) and
CD25-CD44- (pro-T4). However, it reduced cell cycling and slowed turnover
only in the pro-T4 subset. From an analysis of bcl-2 transgenic mice
expressing a TCR transgene or bearing a mutation in the scid or rag-1 gene
we conclude that Bcl-2 inhibits proliferation only of T cell progenitors
that are activated via the pre- TCR, not those stimulated via c-Kit and the
IL-7 receptor.
相似文献
7.
Mutations in the Ca(2+)-sensing receptor gene cause autosomal dominant and sporadic hypoparathyroidism 总被引:3,自引:0,他引:3
Baron J; Winer KK; Yanovski JA; Cunningham AW; Laue L; Zimmerman D; Cutler GB Jr 《Human molecular genetics》1996,5(5):601-606
Parathyroid hormone secretion is negatively regulated by a 7- transmembrane
domain, G-protein coupled Ca(2+)-sensing receptor. We hypothesized that
activating mutations in this receptor might cause autosomal dominant
hypoparathyroidism (ADHP). Consistent with this hypothesis, we identified,
in two families with ADHP, heterozygous missense mutations in the
Ca(2+)-sensing receptor gene that cosegregated with the disorder. None of
50 normal controls had either mutation. We also identified a de novo,
missense Ca(2+)-sensing receptor mutation in a child with severe sporadic
hypoparathyroidism. The amino acid substitution in one ADHP family affected
the N-terminal, extracellular domain of the receptor. The other mutations
involved the transmembrane region. Unlike patients with acquired
hypoparathyroidism, patients with these mutations had hypercalciuria even
at low serum calcium concentrations. Their greater hypercalciuria
presumably reflected activation of Ca(2+)-sensing receptors in kidney
cells, where the receptor negatively regulates calcium reabsorption. This
augmented hypercalciuria increases the risk of renal complications and thus
has implications for the choice of therapy.
相似文献
8.
Symptomatic peripheral arterial disease: the value of a validated questionnaire and a clinical decision rule
下载免费PDF全文
![点击此处可从《The British journal of general practice》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bianca LW Bendermacher Joep AW Teijink Edith M Willigendael Marie-Louise Bartelink Harry R Büller Ron JG Peters Jelis Boiten Machteld Langenberg Martin H Prins 《The British journal of general practice》2006,56(533):932-937
BACKGROUND: If a validated questionnaire, when applied to patients reporting with symptoms of intermittent claudication, could adequately discriminate between those with and without peripheral arterial disease, GPs could avoid the diagnostic measurement of the ankle brachial index. AIM: To investigate the Edinburgh Claudication Questionnaire (ECQ) in general practice and to develop a clinical decision rule based on risk factors to enable GPs to easily assess the likelihood of peripheral arterial disease. DESIGN OF STUDY: An observational study. SETTING: General practice in The Netherlands. METHOD: This observational study included patients of > or =55 years visiting their GP for symptoms suggestive of intermittent claudication or with one risk factor. The ECQ and the ankle brachial index were performed. The prevalence of peripheral arterial disease, defined as an ankle brachial index <0.9, was related to risk factors using logistic regression analyses, on which a clinical decision rule was developed and related to the presence of peripheral arterial disease. RESULTS: Of the 4790 included patients visiting their GP with symptoms suggestive of intermittent claudication, 4527 were eligible for analyses. The prevalence of peripheral arterial disease in this group was 48.3%. The sensitivity of the ECQ was only 56.2%. The prevalence of peripheral arterial disease in a clinical decision rule that included age, male sex, smoking, hypertension, hypercholesterolemia, and a positive ECQ, increased from 14% in the lowest to 76% in the highest category. CONCLUSION: This study indicates that the ECQ alone has an inadequate diagnostic value in detecting patients with peripheral arterial disease. The ankle brachial index should be performed to diagnose peripheral arterial disease in patients with complaints suggestive of intermittent claudication, although our clinical decision rule could help to differentiate between extremely high and lower prevalence of peripheral arterial disease. 相似文献
9.
Expression of collagen, interstitial collagenase, and tissue inhibitor of metalloproteinases-1 in restenosis after carotid endarterectomy. 总被引:3,自引:2,他引:3
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S. T. Nikkari R. L. Geary T. Hatsukami M. Ferguson R. Forough C. E. Alpers A. W. Clowes 《The American journal of pathology》1996,148(3):777-783
Extracellular matrix is the principal component of the fibrous caps of atherosclerotic plaques and intimal hyperplastic lesions of reconstructed arteries. Interstitial collagen form an important part of the matrix, and the balance between collagen synthesis and degradation by interstitial collagenase (matrix metalloproteinase-1, MMP-1) may determine whether plaques rupture or vessels develop stenosis. We examined type I procollagen gene expression in human atherosclerotic and restenotic carotid arteries using in situ messenger RNA (mRNA) hybridization and the expression of MMP-1 and its endogenous inhibitor (tissue inhibitor of metalloproteinases-1, TIMP-1) by immunohistochemistry. Compared with normal arteries, atherosclerotic plaques bed increased expression of immunoreactive MMP-1 and TIMP-1 with modest increase of type 1 procollagen mRNA. Early restenotic lesions (< 1.5 years) contained abundant type I procollagen mRNA but little immunoreactive MMP-1 and TIMP-1. Late restenotic lesions (> 4 years) resembled atheroma and exhibited increased immunoreactive MMP-1 and TIMP-1 as well as abundant type I procollagen mRNA. Compared with atherosclerotic plaques, type I procollagen is increased and MMP-1 is decreased in early restenotic lesions. MMP-1 and TIMP-1 expressions are upregulated in lesions with a clear atheroma. These findings suggest that the balance between proteolysis and matrix synthesis may influence both the stability of atheromatous plaques and the development of restenotic lesions. 相似文献
10.
Three young family members with recurrent arterial thrombosis underwent investigation for lipid or coagulation abnormalities. Lipoprotein electrophoresis, cholesterol, triglyceride levels, and routine coagulation studies were unremarkable. By contrast, testing of platelet function showed enhanced platelet aggregability to epinephrine and collagen in two of the subjects. In addition, release of 14C-serotonin by adenosine diphosphate and epinephrine was increased over control values in these same two patients. The third subject demonstrated decreased platelet aggregation and lowered 14C-serotonin release, but was symptomatic with rest pain at the time of testing. The ongoing in vivo thrombosis in the third subject may account for hypocoagulable platelets by in vitro testing. These abnormally sensitive platelets identified by platelet function testing may be associated with a familial "hypercoagulability" syndrome. Definition of the hemostatic abnormality in these individuals provided a rational basis for pharmacological therapy with antiplatelet drugs, which appeared to be successful. 相似文献