全文获取类型
收费全文 | 637篇 |
免费 | 21篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 112篇 |
妇产科学 | 8篇 |
基础医学 | 72篇 |
口腔科学 | 11篇 |
临床医学 | 53篇 |
内科学 | 150篇 |
皮肤病学 | 4篇 |
神经病学 | 11篇 |
特种医学 | 133篇 |
外科学 | 29篇 |
综合类 | 11篇 |
预防医学 | 28篇 |
眼科学 | 3篇 |
药学 | 29篇 |
肿瘤学 | 23篇 |
出版年
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 3篇 |
2014年 | 13篇 |
2013年 | 16篇 |
2012年 | 18篇 |
2011年 | 18篇 |
2010年 | 15篇 |
2009年 | 18篇 |
2008年 | 19篇 |
2007年 | 26篇 |
2006年 | 23篇 |
2005年 | 23篇 |
2004年 | 23篇 |
2003年 | 10篇 |
2002年 | 13篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 12篇 |
1998年 | 34篇 |
1997年 | 19篇 |
1996年 | 24篇 |
1995年 | 18篇 |
1994年 | 23篇 |
1993年 | 13篇 |
1992年 | 11篇 |
1991年 | 14篇 |
1990年 | 15篇 |
1989年 | 24篇 |
1988年 | 37篇 |
1987年 | 15篇 |
1986年 | 21篇 |
1985年 | 23篇 |
1984年 | 13篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 13篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1973年 | 2篇 |
1947年 | 1篇 |
1898年 | 1篇 |
排序方式: 共有678条查询结果,搜索用时 15 毫秒
671.
Kathrin Ludwig Matteo Fassan Claudia Mescoli Marco Pizzi Mariangela Balistreri Laura Albertoni Salvatore Pucciarelli Marco Scarpa Giacomo Carlo Sturniolo Imerio Angriman Massimo Rugge 《Virchows Archiv : an international journal of pathology》2013,462(1):57-63
Inflammatory bowel diseases (IBDs; both ulcerative colitis [UC] and Crohn’s colitis [CC]) are well-established predisposing pathological conditions for colorectal cancer (CRC) development. In IBDs, both the endoscopy and the histology assessment of CRC precursors (i.e., dysplasia, also defined as intraepithelial neoplasia) are associated with low interobserver consistency, and no reliable dysplasia-specific biomarker is available. The programmed cell death 4 (PDCD4) tumor suppressor gene is involved in sporadic colorectal oncogenesis, but scanty information is available on its involvement in IBD-associated colorectal oncogenesis. One hundred twenty tissue samples representative of active and inactive IBD and of flat dysplasia were obtained from 30 cases of UC and 30 of CC who undergone colectomy. Twenty additional biopsy samples obtained from patients with irritable bowel syndrome acted as normal controls. PDCD4 expression was assessed by immunohistochemistry; the expression of miR-21 (a major PDCD4 regulator) was investigated by quantitative real-time PCR and in situ hybridization in different series of a hundred samples. Tissue specimens from both controls and inactive IBD consistently featured strong PDCD4 nuclear immunostain; conversely, lower PDCD4 nuclear expression was featured by both active IBD and IBD-associated dysplastic lesions. Significant PDCD4 down-regulation distinguished IBD-associated dysplasia (p?<?0.001) versus active IBD. In both active IBD and dysplasia, PDCD4 down-regulation was significantly associated with miR-21 up-regulation. PDCD4 nuclear down-regulation (which parallels miR-21 up-regulation) is involved in the molecular pathway of IBD-associated carcinogenesis. PDCD4 nuclear expression may be usefully applied as ancillary maker in the histological assessment of IBD-associated dysplastic lesions. 相似文献
672.
673.
674.
SL Schor I Ellis CR Irwin J Banyard K Seneviratne C Dolman AD Gilbert DM Chisholm 《Oral diseases》1996,2(2):155-166
Wound healing in the adult is commonly compromised by excessive scar formation. In contrast, fetal wound healing is a regenerative process characterised by the conspicuous absence of scarring. Available evidence suggests that phenotypic differences between fetal and adult fibroblasts are important determinants of these distinct modes of tissue repair. In this context, a number of groups (including our own) have documented differences between fetal and adult fibroblasts with respect to such potentially relevant characteristics as migratory activity, motogenic response to cytokines and the synthesis of motility factors, cytokines and matrix macromolecules. The oral mucosa appears to be a privileged site in the adult in that it continues to display a fetal-like mode of wound healing. Data are presented in this review indicating that a subpopulation of gingival fibroblasts expresses several 'fetal-like' phenotypic characteristics. These observations are discussed in terms of both the continued expression of a fetal-like mode of wound healing in the oral mucosa and the possible differential involvement of distinct fibroblast subpopulations in the progression of periodontal disease. 相似文献
675.
ObjectiveTo investigate the nutritional status of the males and females in two subgroups of the Bhotia tribe (Marcha and Tolcha) inhabiting in three different altitudes in Uttaranchal, India.MethodsData were collected from the Tolcha and Marcha, two sub-groups of the Bhotia, inhabiting in Chamoli district of Uttaranchal. Bhotia adults of both sexes were considered. Field investigation was conducted in three ecological zones (high, middle and low altitude) of the district during April-August, in the years 2002-2004. Anthropometric measurements were obtained in accordance with the techniques recommended by Weiner and Lourie (1981). The variables like height, weight, waist circumference, hip circumference, waist-hip ratio and blood pressure were studied in relation to BMI.ResultsRelatively higher value of mean BMI is recorded among the females than that of the males, which is true for different altitudes, in both subgroups. The BMI also indicates an inverse relationship with altitude, except for the Tolcha males in high altitude. Lowest mean BMI is recorded in middle altitude among the Tolcha subgroup. Chronic energy deficient (CED) individuals are much more than twice the number among the males of both the subgroups inhabiting in different altitudes. Interestingly, the percentage of CED individuals increases with the altitude.ConclusionsRegression analysis indicates that height, weight, hip circumference and waist circumference are dependent on body mass index in the studied populations. Probable reason for poor nutrition status among the Tolcha and Marcha of high altitude might be due to the fact that the Tolcha and Marcha of high altitude consume lesser amount of proteins, fat, milk and milk products in general than their counterpart inhabit in lower and middle altitude. 相似文献
676.
CR de Andrade PF Leite AC Montezano DA Casolari A Yogi RC Tostes R Haddad MN Eberlin FRM Laurindo HP de Souza FMA Corr��a AM de Oliveira 《British journal of pharmacology》2009,157(4):568-580
Background and purpose:
There are interactions between endothelin-1 (ET-1) and endothelial vascular injury in hyperhomocysteinemia (HHcy), but the underlying mechanisms are poorly understood. Here we evaluated the effects of HHcy on the endothelin system in rat carotid arteries.Experimental approach:
Vascular reactivity to ET-1 and ETA and ETB receptor antagonists was assessed in rings of carotid arteries from normal rats and those with HHcy. ETA and ETB receptor expression was assessed by mRNA (RT-PCR), immunohistochemistry and binding of [125I]-ET-1.Key results:
HHcy enhanced ET-1-induced contractions of carotid rings with intact endothelium. Selective antagonism of ETA or ETB receptors produced concentration-dependent rightward displacements of ET-1 concentration response curves. Antagonism of ETA but not of ETB receptors abolished enhancement in HHcy tissues. ETA and ETB receptor gene expressions were not up-regulated. ETA receptor expression in the arterial media was higher in HHcy arteries. Contractions to big ET-1 served as indicators of endothelin-converting enzyme activity, which was decreased by HHcy, without reduction of ET-1 levels. ET-1-induced Rho-kinase activity, calcium release and influx were increased by HHcy. Pre-treatment with indomethacin reversed enhanced responses to ET-1 in HHcy tissues, which were reduced also by a thromboxane A2 receptor antagonist. Induced relaxation was reduced by BQ788, absent in endothelium-denuded arteries and was decreased in HHcy due to reduced bioavailability of NO.Conclusions and implications:
Increased ETA receptor density plays a fundamental role in endothelial injury induced by HHcy. ET-1 activation of ETA receptors in HHcy changed the balance between endothelium-derived relaxing and contracting factors, favouring enhanced contractility.British Journal of Pharmacology (2009) 157, 568–580; doi:10.1111/j.1476-5381.2009.00165.x; published online 9 April 2009This article is part of a themed section on Endothelium in Pharmacology. For a list of all articles in this section see the end of this paper, or visit: http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2009 相似文献677.
Perlmutter DH Brodsky JL Balistreri WF Trapnell BC 《Hepatology (Baltimore, Md.)》2007,45(5):1313-1323
In recent years, we have witnessed several important paradigm shifts in understanding the molecular basis of liver disease in alpha-1-antitrypsin (AT) deficiency. These shifts have become possible as a result of a number of advances in research on the cell biology of aggregation-prone mutant proteins and in research on the pathobiological mechanisms of liver disease in general. Late-breaking research in these areas was the subject of an AASLD/Alpha-1 Foundation Single Topic Conference in Atlanta, Georgia, on January 26 to 28, 2006. The conference was titled "Alpha-1-Antitrypsin Deficiency and Other Liver Diseases Caused by Aggregated Proteins." Investigators from all over the world, representing a broad array of scientific disciplines and perspectives, discussed the pathobiology of AT deficiency, mechanisms of cell injury in diseases associated with aggregation-prone proteins, pathways by which cells respond to protein aggregation and mislocalization, and mechanisms of liver injury in general and in diseases related to AT deficiency. A session of the meeting was devoted to novel therapeutic strategies being developed for AT deficiency as well as to strategies either in development or already being applied to the class of diseases associated with mutant proteins. 相似文献
678.
A Marceline Tutu van Furth Martijn van der Kuip Anne L van Els Lydia CR Fievez Gini GC van Rijckevorsel Anton van den Ouden Marcel Jonges Matthijs RA Welkers 《Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin》2022,27(29)
Since May 2022, an international monkeypox (MPX) outbreak has been ongoing in more than 50 countries. While most cases are men who have sex with men, transmission is not restricted to this population. In this report, we describe the case of a male child younger than 10 years with MPX in the Netherlands. Despite thorough source tracing, a likely source of infection has not been identified. No secondary cases were identified in close contacts. 相似文献