全文获取类型
收费全文 | 704篇 |
免费 | 108篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 8篇 |
妇产科学 | 4篇 |
基础医学 | 198篇 |
口腔科学 | 4篇 |
临床医学 | 109篇 |
内科学 | 190篇 |
皮肤病学 | 16篇 |
神经病学 | 52篇 |
特种医学 | 10篇 |
外科学 | 49篇 |
综合类 | 12篇 |
预防医学 | 29篇 |
眼科学 | 5篇 |
药学 | 32篇 |
肿瘤学 | 97篇 |
出版年
2023年 | 6篇 |
2022年 | 5篇 |
2021年 | 11篇 |
2020年 | 9篇 |
2019年 | 9篇 |
2018年 | 19篇 |
2017年 | 12篇 |
2016年 | 15篇 |
2015年 | 22篇 |
2014年 | 19篇 |
2013年 | 36篇 |
2012年 | 54篇 |
2011年 | 53篇 |
2010年 | 27篇 |
2009年 | 32篇 |
2008年 | 52篇 |
2007年 | 67篇 |
2006年 | 65篇 |
2005年 | 49篇 |
2004年 | 46篇 |
2003年 | 40篇 |
2002年 | 43篇 |
2001年 | 16篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1998年 | 15篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1971年 | 2篇 |
排序方式: 共有816条查询结果,搜索用时 15 毫秒
11.
Structural and functional macrophages alterations by ceramics of different composition 总被引:2,自引:0,他引:2
Bosetti M Ottani V Kozel D Raspanti M De Pasquale V Ruggeri A Cannas M 《Biomaterials》1999,20(4):363-370
Biomaterials may initiate several and complex biological reactions in host tissues, and the cell-biomaterial interactions can determine the release of mediators including monocytes and lymphocytes chemotactic factors. The present work was aimed to investigate in vitro the macrophage biological reactions of a natural apatite obtained by heat treatment at 400 degrees C of bovine bone, compared to other ceramics usually used for dental and orthopedic applications, using synthetic apatite and three types of alumina as controls. Particles chemotactic activity and powders oxidative burst evidenced no monocyte macrophages sensitivity reaction for natural and synthetic hydroxyapatite powders at great granulometry (> 50 microm); data were confirmed by ultrastructural observations; electron microscopy analysis showed macrophages with the features of healthy cells in the presence of both natural and synthetic apatites while macrophages grown in the presence of alumina seemed to be negatively affected. In conclusion, among all ceramics tested, natural apatite displayed a good compatibility with living cells, being better tolerated than synthetic hydroxyapatite which in turn is better tolerated than alumina. 相似文献
12.
V V Gafarov Iu V Smirnova Ia Sh Gatkin N G Kozel S V Vo?nitskaia I V Gagulin M I Voevoda E G Markevich T G Klimenkova T A Filimonova 《Terapevticheski? arkhiv》1991,63(11):106-110
The authors analyze the results of investigations in accordance with the WHO program "MONICA" in one of the districts of Novosibirsk. The bases of the objective information system pertaining to the tendencies in mortality, morbidity and lethality due to cardiovascular diseases, the prevalence of risk factors in the population, the possibilities of their monitoring have been established. 相似文献
13.
Emily A Nizialek Jessica L Mester Vineet K Dhiman Dominic J Smiraglia Charis Eng 《European journal of human genetics : EJHG》2015,23(11):1538-1543
Germline KLLN promoter hypermethylation was recently identified as a potential genetic etiology of the cancer predisposition syndrome, Cowden syndrome (CS), when no causal PTEN gene mutation was found. We screened for KLLN promoter methylation in a large prospective series of CS patients and determined the risk of benign and malignant CS features in patients with increased methylation both with and without a PTEN mutation/variant of unknown significance. In all, 1012 CS patients meeting relaxed International Cowden Consortium criteria including 261 PTEN mutation-positive CS patients, 187 PTEN variant-positive CS patients and 564 PTEN mutation-negative CS patients, as well as 111 population controls were assessed for germline KLLN promoter methylation by MassARRAY EpiTYPER analysis. KLLN promoter methylation was analyzed both as a continuous and a dichotomous variable in the calculation of phenotypic risks by stepwise logistic regression and Kaplan–Meier/standardized incidence ratio methods, respectively. Significantly increased KLLN promoter methylation was seen in CS individuals with and without a PTEN mutation/VUS compared with controls (P<0.001). Patients with high KLLN promoter methylation have increased risks of all CS-associated malignancies compared with the general population. Interestingly, KLLN-associated risk of thyroid cancer appears to be gender and PTEN status dependent. KLLN promoter methylation associated with different benign phenotypes dependent on PTEN status. Furthermore, increasing KLLN promoter methylation is associated with a greater phenotype burden in mutation-negative CS patients. Germline promoter hypermethylation of KLLN is associated with particular malignant and benign CS features, which is dependent on the PTEN mutation status. 相似文献
14.
Pietrella D Kozel TR Monari C Bistoni F Vecchiarelli A 《The Journal of infectious diseases》2001,183(1):51-58
The mechanism involved in the envelope glycoprotein gp120-induced Th2 response to Cryptococcus neoformans was investigated. Peripheral blood mononuclear cells (PBMC) from healthy donors were treated with human immunodeficiency virus gp120 and an encapsulated or acapsular strain of C. neoformans in the presence or absence of glucuronoxylomannan, the major capsular polysaccharide. gp120 inhibited early and late production of interleukin (IL)-12 by PBMC. This reduction paralleled IL-10 induction and inhibited translocation of CD40 to the surface of monocytes. Flow cytometric analysis revealed that gp120 down-regulated the expression of IL-12 receptor beta2 subunit on T cells responding to C. neoformans. Because the IL-12/IL-12 receptor beta2 subunit pathway is critical for the Th1 differentiation process, underexpression demonstrates that gp120 contributes to Th2 bias. Exogenous IL-12 added simultaneously with gp120 up-regulated interferon-gamma secretion and limited IL-4 production. These results suggest that gp120 limits the Th1 response to C. neoformans and that exogenous IL-12 could offset this effect. 相似文献
15.
Sanja Percac-Lima Lydia E. Pace Kevin H. Nguyen Charis N. Crofton Katharine A. Normandin Sara J. Singer Meredith B. Rosenthal Alyna T. Chien 《Journal of general internal medicine》2018,33(4):415-422
Background
Rectal bleeding is a common, frequently benign problem that can also be an early sign of colorectal cancer. Diagnostic evaluation for rectal bleeding is complex, and clinical practice may deviate from available guidelines.Objective
To assess the degree to which primary care physicians document risk factors for colorectal cancer among patients with rectal bleeding and order colonoscopies when indicated, and the likelihood of physicians ordering and patients receiving recommended colonoscopies based on demographic characteristics, visit patterns, and clinical presentations.Design
Cross-sectional study using explicit chart abstraction methods.Participants
Three hundred adults, 40–80 years of age, presenting with rectal bleeding to 15 academically affiliated primary care practices between 2012 and 2016.Main Measures
1) The frequency at which colorectal cancer risk factors were documented in patients’ charts, 2) the frequency at which physicians ordered colonoscopies and patients received them, and 3) the odds of ordering and patients receiving recommended colonoscopies based on patient demographic characteristics, visit patterns, and clinical presentations.Key Results
Risk factors for colorectal cancer were documented between 9% and 66% of the time. Most patients (89%) with rectal bleeding needed a colonoscopy according to a clinical guideline. Physicians placed colonoscopy orders for 74% of these patients, and 56% completed the colonoscopy within a year (36% within 60 days). The odds of physicians ordering recommended colonoscopies were significantly higher in patients aged 50–64 years of age than in those aged 40–50 years (OR?=?2.23, 95% CI: 1.04, 4.80), and for patients whose most recent colonoscopy was 5 or more years ago (OR?=?4.04, 95% CI: 1.50, 10.83). The odds of physicians ordering and patients receiving recommended colonoscopies were significantly lower for each primary care visit unrelated to rectal bleeding (OR?=?0.85, 95% CI: 0.75, 0.96).Conclusions
Diagnostic evaluation of patients presenting to primary care with rectal bleeding may be suboptimal because of inadequate risk factor assessment and prioritization of patients’ other concurrent medical problems.16.
Are acute exacerbations of chronic inflammatory appendicitis triggered by coprostasis and/or coproliths? 总被引:1,自引:0,他引:1
Sgourakis G Sotiropoulos GC Molmenti EP Eibl C Bonticous S Moege J Berchtold C 《World journal of gastroenterology : WJG》2008,14(20):3179-3182
AIM- To examine the role of coprostasis and coproliths in recurrent appendicitis. METHODS: We evaluated four hundred and twenty seven consecutive pathology reports of all appendectomy specimens from January 2003 to December 2004. Findings were categorised as showing acute appendicitis, acute recurrent appendicitis, subacute recurrent appendicitis, chronic appendicitis, or appendices without inflammation. All patients had presented with acute right lower quadrant pain, In 94 instances, there was a history of recurrent similar episodes in the past. RESULTS: Of the 427 histology reports, 294 were inter- preted as showing acute appendicitis, 56 acute recurrent appendicitis, 34 subacute recurrent appen-dicitis, 28 chronic appendicitis, and 15 non-inflamed appendices. Coprostasis was observed in 58 patients (13.58%) and the presence of coprolith in 6 (1.4%). Coprostasis, and age, were among the predictors in the final model. CONCLUSION: Coprostasis but not coproliths seems to be a contributing factor to acute exacerbations of chronic inflammatory appendicitis. 相似文献
17.
Papadaki HA Eliopoulos DG Ponticoglou C Eliopoulos GD 《International journal of hematology》2001,73(3):339-345
This study describes the frequency of monoclonal gammopathy of undetermined significance (MGUS) and the changes in some inflammation-related serum proteins in 157 patients with nonimmune chronic idiopathic neutropenia syndrome (NI-CINS). Of these patients, 42 had pronounced neutropenia with neutrophil counts < 1500/microL, and 115 had mild neutropenia with neutrophil counts ranging from 1500 to 2499/microL. Sixty-six volunteers served as healthy control subjects and 157 age- and sex-matched patients hospitalized for nonmalignant diseases served as patient control subjects. We found that 28.6% of patients with pronounced neutropenia and 14.8% of patients with mild neutropenia had increased serum gamma globulins (above the 95% confidence limit of values of the control subjects). In the group of patients with pronounced neutropenia, 30.9% had increased immunoglobulin (Ig)G values and 23.8% had increased IgA values. In the group of patients with mild neutropenia, 17.4% had increased IgG values and 21.7% had increased IgA values. IgG and IgA values strongly correlated with the neutrophil count. No changes in serum IgM were found. Three of 42 patients with pronounced neutropenia (7.14%) and 3 of 115 patients with mild neutropenia (2.61%) had serum immunofixation tests which showed a small monoclonal spike--4 were IgG-kappa type, 1 was IgG-lambda type, and 1 was IgA-kappa type. None of the healthy or patient control subjects had any evidence of MGUS. No significant changes in the amount of monoclonal spikes were documented during an 18- to 143-month follow-up (median, 58 months). Except for significantly increased alpha1-antitrypsin levels, there were no significant differences in the levels of acute-phase proteins studied between the study patients and the control subjects. These findings are consistent with our previous report suggesting the possible existence of an unrecognized low-grade chronic inflammation in patients with NI-CINS, which may be involved in the pathogenesis of neutropenia in the affected subjects. 相似文献
18.
FoxP3+ regulatory T (Treg) cells comprise a highly dynamic population that restrains autoreactivity. Although complete or long‐term depletion of Foxp3+CD4+ Treg cells in adult mice has been shown to result in chronic inflammation and autoimmune disease, the impact of transient Treg‐cell depletion on self‐reactive responses is poorly defined. A new study published in this issue of the European Journal of Immunology [Eur. J. Immunol. 2014. 44: 3621–3631] shows that, although transient depletion of Treg cells in mice is swiftly followed by recovery of Treg‐cell numbers, the “rebounded” population fails to maintain tolerance, culminating in severe autoimmune gastritis. This commentary explores new questions about the quantitative and qualitative aspects of Treg‐cell function in immunological tolerance raised by this study and others. 相似文献
19.
Heindl M Händel N Ngeow J Kionke J Wittekind C Kamprad M Rensing-Ehl A Ehl S Reifenberger J Loddenkemper C Maul J Hoffmeister A Aretz S Kiess W Eng C Uhlig HH 《Gastroenterology》2012,142(5):1093-1096.e6
The Phosphatase And Tensin Homolog Deleted On Chromosome 10 (PTEN) regulates the phosphoinositol-3-kinase (PI3K)-AKT signaling pathway. In a series of 34 patients with PTEN mutations, we described gastrointestinal lymphoid hyperplasia, extensive hyperplastic tonsils, thymus hyperplasia, autoimmune lymphocytic thyroiditis, autoimmune hemolytic anemia, and colitis. Functional analysis of the gastrointestinal mucosa-associated lymphoid tissue revealed increased signaling via the PI3K-AKT pathway, including phosphorylation of S6 and increased cell proliferation, but also reduced apoptosis of CD20(+)CD10(+) B cells. Reduced activity of PTEN therefore affects homeostasis of human germinal center B cells by increasing PI3K-AKT signaling via mammalian target of rapamycin as well as antiapoptotic signals. 相似文献
20.
Bimpis A Papalois A Tsakiris S Zarros A Kalafatakis K Botis J Stolakis V Zissis KM Liapi C 《Metabolic brain disease》2012,27(2):221-225
Spontaneous intracerebral hemorrhage (ICH) accounts for 10–15% of all strokes. Despite high incidence, morbidity and mortality,
the precise pathophysiology of spontaneous ICH is not fully understood, while there is little data concerning the mechanisms
that follow the primary insult of the hematoma formation. The cholinergic system, apart from its colossal importance as a
neurotransmission system, seems to also play an important role in brain injury recovery. It has been recently suggested that
the brain possesses a cholinergic anti-inflammatory pathway that counteracts the inflammatory responses after ICH, thereby
limiting damage to the brain itself. We, herein, report the findings of our study concerning the role of acetylcholinesterase
(AChE; a crucial membrane-bound enzyme involved in cholinergic neurotransmission) in a porcine model of spontaneous ICH, with
a focus on the first 4 and 24 h following the lesion’s induction, in combination with a study of the effectiveness of the
lazaroid antioxidant U-74389G administration. Our study demonstrates the activation of AChE activity following U-74389G administration.
The lazaroid U-74389G seems to be an established neuroprotectant and this is the first report of its supporting role in the
enhancement of cholinergic response to the induction of ICH. 相似文献