全文获取类型
收费全文 | 2500篇 |
免费 | 181篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 21篇 |
妇产科学 | 40篇 |
基础医学 | 262篇 |
口腔科学 | 40篇 |
临床医学 | 194篇 |
内科学 | 546篇 |
皮肤病学 | 19篇 |
神经病学 | 262篇 |
特种医学 | 387篇 |
外科学 | 367篇 |
综合类 | 5篇 |
一般理论 | 1篇 |
预防医学 | 92篇 |
眼科学 | 37篇 |
药学 | 102篇 |
中国医学 | 1篇 |
肿瘤学 | 276篇 |
出版年
2024年 | 5篇 |
2023年 | 47篇 |
2022年 | 44篇 |
2021年 | 82篇 |
2020年 | 70篇 |
2019年 | 95篇 |
2018年 | 106篇 |
2017年 | 73篇 |
2016年 | 101篇 |
2015年 | 99篇 |
2014年 | 119篇 |
2013年 | 130篇 |
2012年 | 213篇 |
2011年 | 213篇 |
2010年 | 120篇 |
2009年 | 138篇 |
2008年 | 166篇 |
2007年 | 163篇 |
2006年 | 122篇 |
2005年 | 136篇 |
2004年 | 104篇 |
2003年 | 98篇 |
2002年 | 90篇 |
2001年 | 15篇 |
2000年 | 14篇 |
1999年 | 11篇 |
1998年 | 15篇 |
1997年 | 16篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1987年 | 7篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1965年 | 3篇 |
1943年 | 3篇 |
1938年 | 1篇 |
1934年 | 2篇 |
排序方式: 共有2694条查询结果,搜索用时 26 毫秒
81.
Hultqvist M Sareila O Vilhardt F Norin U Olsson LM Olofsson P Hellman U Holmdahl R 《Antioxidants & redox signaling》2011,14(12):2373-2383
The Ncf1 gene, encoding the P47(PHOX) protein that regulates production of reactive oxygen species (ROS) by the phagocyte NADPH oxidase (NOX2) complex, is associated with autoimmunity and arthritis severity in rats. We have now identified that the single-nucleotide polymorphism (SNP) resulting in an M153T amino acid substitution mediates arthritis resistance and thus explains the molecular polymorphism underlying the earlier identified Ncf1 gene effect. We identified the SNP in position 153 to regulate ROS production using COS(PHOX) cells transfected with mutated Ncf1. To determine the role of this SNP for control of arthritis, we used the Wistar strain, identified to carry only the postulated arthritis resistant SNP in position 153. When this Ncf1 allele was backcrossed to the arthritis susceptible DA strain, both granulocyte ROS production and arthritis resistance were restored. Position 153 is located in the hinge region between the PX and SH3 domains of P47(PHOX). Mutational analysis of this position revealed a need for an -OH group in the side chain but we found no evidence for phosphorylation. The polymorphism did not affect assembly of the P47(PHOX)/P67(PHOX) complex in the cytosol or membrane localization, but is likely to operate downstream of assembly, affecting activity of the membrane NOX2 complex. 相似文献
82.
Patrick Maschmeyer Gitta Anne Heinz Christopher Mark Skopnik Lisanne Lutter Alessio Mazzoni Frederik Heinrich Sae Lim von Stuckrad Lorenz Elias Wirth Cam Loan Tran René Riedel Katrin Lehmann Imme Sakwa Rolando Cimaz Francesco Giudici Marcus Alexander Mall Philipp Enghard Bas Vastert Hyun-Dong Chang Pawel Durek Francesco Annunziato Femke van Wijk Andreas Radbruch Tilmann Kallinich Mir-Farzin Mashreghi 《European journal of immunology》2021,51(4):915-929
83.
Pourkarim MR Lemey P Amini-Bavil-Olyaee S Houspie L Verbeeck J Rahman M Maes P Vanwijngaerden E Nevens F Van Ranst M 《Journal of medical virology》2011,83(11):1876-1884
Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) have similar transmission routes, implying that patients infected with HIV are at particular risk for HBV infection. Patients who are co-infected with HIV and HBV progress more rapidly to end-stage liver disease and different HBV genotypes may have a distinct impact on disease progression. One hundred ninety-one anti-HBc-positive sera from Belgian patients co-infected with HIV and HBV were collected during 1998-2008. Full-length HBV genomes as well as large S or partial S genes were amplified and their molecular evolutionary history was analyzed. Clinically, 30 (65.8%) patients were categorized as "overt infection" and 16 (34.7%) cases were categorized as "occult infection." Five distinct HBV genotypes comprising A (69.6%), E (19.6%), followed by D, C, and G were detected. HBV genotype A was observed in all clinical groups and in patients with varying ethnical background. HBV genotype E could be detected in African patients who were mostly infected by heterosexual contacts. Several clinically important mutations at the HBs major hydrophilic region were detected in the new isolates but with no significant difference between occult and overt infection. The high prevalence of HBV genotype A in overt and occult cases, and in particular the detection of certain HBV subgenotypes in patients co-infected with HIV and HBV that carry diagnostic escape mutations, may provide useful information for national guidelines for prophylaxis and treatment. 相似文献
84.
Vincent Vandecaveye Frederik De Keyzer Piet Dirix Maarten Lambrecht Sandra Nuyts Robert Hermans 《Neuroradiology》2010,52(9):773-784
In the head and neck, squamous cell carcinoma is one of the most common tumour types. Currently, the primary imaging modalities for initial locoregional staging are computed tomography and—to a lesser extent—magnetic resonance imaging, whilst [18F]fluorodeoxyglucose (FDG) positron emission tomography has additional value in the detection of subcentimetric metastatic lymph nodes and of tumour recurrence after chemoradiotherapy (CRT). However, dependency on the morphological and size-related criteria of anatomical imaging and the limited spatial resolution and FDG avidity of inflammation in metabolic imaging may reduce diagnostic accuracy in the head and neck. Diffusion-weighted magnetic resonance imaging (DWI) is a noninvasive imaging technique that measures the differences in water mobility in different tissue microstructures. Water mobility is likely influenced by cell size, density, and cellular membrane integrity and is quantified by means of the apparent diffusion coefficient. As such, the technique is able to differentiate tumoural tissue from normal tissue, inflammatory tissue and necrosis. In this article, we examine the use of DWI in head and neck cancer, focussing on technique optimization and image interpretation. Afterwards, the value of DWI will be outlined for clinical questions regarding nodal staging, lesion characterization, differentiation of post-CRT tumour recurrence from necrosis and inflammation, and predictive imaging towards treatment outcome. The possible consequences of adding DWI towards therapeutic management are outlined. 相似文献
85.
Bei vielen Organentitäten ist das neoadjuvante Konzept mittlerweile etablierter Bestandteil der Therapie. Die neoadjuvante Therapie scheint auch in speziellen Situationen für Zervixkarzinompatientinnen interessant. Dieser Artikel soll einen Überblick über die aktuell diskutierten Einsatzgebiete in der Neoadjuvanz beim Zervixkarzinom darlegen, die verschiedenen Optionen werden besprochen. Als Grundlage für diesen Artikel dient die S3-Leitlinie Diagnostik, Therapie und Nachsorge der Patientin mit Zervixkarzinom AWMF(Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften)-Registernummer 032/033OL in der Version von 2014. Diese wurde durch die Literatur zur Update-Recherche der Neufassung der Leitlinie erweitert. Die NACT(neoadjuvante Chemotherapie)-Ansprechrate liegt bei 84 %, das progressionsfreie Überleben (PFS) über 5 Jahre und das Gesamtüberleben (OS) betragen 61,9 und 72,8 %. Das Ansprechen auf eine NACT korreliert mit einem besseren Langzeitüberleben. In einer Cochrane-Analyse von 2012 wurde gezeigt, dass eine neoadjuvante Chemotherapie vor geplanter Operation zu einer Verbesserung des PFS (HR [Hazard Ratio] 0,75, 95 %-KI [Konfidenzintervall] 0,61–0,93, p = 0,008) und des Gesamtüberlebens (HR 0,77, 95 %-KI 0,62–0,96, p = 0,02) führt. Unter Berücksichtigung des Random-Effekt-Modells war der Effekt aber nicht mehr signifikant (OR [Odds Ratio] 0,60, 95 %-KI 0,32–1,12, p = 0,11). Bei makroinvasiven Karzinomen in der Schwangerschaft vor einer möglichen Entbindung ist die NACT fester Bestandteil der Therapie. Die Datenlage zum Einsatz der neoadjuvanten Therapie beim Zervixkarzinom ist unklar. Die neoadjuvante Therapie ist aktuell kein Standard in der Behandlung des Zervixkarzinoms. Ungeklärt ist auch die Rolle des operativen Stagings und positiver Lymphknoten nach der neoadjuvanten Therapie. In verschiedenen Metaanalysen konnte gezeigt werden, dass die neoadjuvante Therapie das PFS und das OS verbessert. Dies gilt insbesondere für Frauen, die auf die neoadjuvante Therapie angesprochen haben. 相似文献
86.
Hsu Phern Chong J. Frederik Frøen Sylvia Richardson Benoit Liquet D. Stephen Charnock-Jones 《The journal of maternal-fetal & neonatal medicine》2019,32(3):411-418
Objectives: We sought to evaluate the impact of later menarche on the risk of operative delivery.Population: We studied 38,069 eligible women (first labors at term with a singleton infant in a cephalic presentation) from the Norwegian Mothers and Child Cohort Study. The main exposures were the age at menarche and the duration of the interval between menarche and the first birth.Methods: Poisson’s regression with a robust variance estimator.Main outcome measures: Operative delivery, defined as emergency cesarean or assisted vaginal delivery (ventouse extraction or forceps).Results: A 5 year increase in age at menarche was associated with a reduced risk of operative delivery (risk ratio [RR] 0.84, 95%CI 0.78, 0.89; p?.001). Adjustment for the age at first birth slightly strengthened the association (RR 0.79, 95%CI 0.74, 0.84; p?.001). However, the association was lost following adjustment for the menarche to birth interval (RR 0.99, 95%CI 0.93, 1.06; p?=?.81). A 5 years increase in menarche to birth interval was associated with an increased risk of operative delivery (RR 1.26, 95%CI 1.23, 1.28; p?.001). This was not materially affected by adjustment for an extensive series of maternal characteristics (RR 1.23, 95%CI 1.20, 1.25; p?.001).Conclusions: Later menarche reduces the risk of an operative first birth through shortening the menarche to birth interval. This observation is consistent with the hypothesis that the pattern and/or duration of prepregnancy exposure of the uterus to estrogen and progesterone contributes to uterine aging. 相似文献
87.
Krüll M Bockstaller P Wuppermann FN Klucken AC Mühling J Schmeck B Seybold J Walter C Maass M Rosseau S Hegemann JH Suttorp N Hippenstiel S 《American journal of respiratory cell and molecular biology》2006,34(3):375-382
Chlamydophila pneumoniae is an important respiratory pathogen. In this study we characterized C. pneumoniae strain TW183-mediated activation of human small airway epithelial cells (SAEC) and the bronchial epithelial cell line BEAS-2B and demonstrated time-dependent secretion of granulocyte macrophage colony-stimulating factor (GM-CSF) upon stimulation. TW183 activated p38 mitogen-activated protein kinase (MAPK) in epithelial cells. Kinase inhibition by SB202190 blocked Chlamydia-mediated GM-CSF release on mRNA and protein levels. In addition, the chemical inhibitor as well as dominant-negative mutants of p38 MAPK isoforms p38alpha, beta2, and gamma inhibited C. pneumoniae-related NF-kappaB activation. In contrast, blocking of MAPK ERK, c-Jun kinase/JNK, or PI-3 Kinase showed no effect on Chlamydia-related epithelial cell GM-CSF release. Ultraviolet-inactivated pathogens as compared with viable bacteria induced a smaller GM-CSF release, suggesting that viable Chlamydiae were only partly required for a full effect. Presence of an antichlamydial outer membrane protein-A (OmpA) antibody reduced and addition of recombinant heat-shock protein 60 from C. pneumoniae (cHsp60, GroEL-1)-enhanced GM-CSF release, suggesting a role of these proteins in epithelial cell activation. Our data demonstrate that C. pneumoniae triggers an early proinflammatory signaling cascade involving p38 MAPK-dependent NF-kappaB activation, resulting in subsequent GM-CSF release. C. pneumoniae-induced epithelial cytokine liberation may contribute significantly to inflammatory airway diseases like chronic obstructive pulmonary disease (COPD) or bronchial asthma. 相似文献
88.
Localization of 5-HT2A, 5-HT3, 5-HT5A and 5-HT7 receptor-like immunoreactivity in the rat cerebellum
Although serotonin (5-hydroxytryptamine, 5-HT) is known to exert a modulatory action on cerebellar function, our current knowledge of the nature of receptor subtypes mediating serotonergic activity in this part of the brain remains fragmentary. In this study, we report the presence and distribution of 5-HT3, 5-HT5A and 5-HT7 receptor-like immunoreactivity in the rat cerebellum using immunofluorescence histochemistry. 5-HT3 immunoreactivity was found in fibers sparsely distributed throughout the cerebellum. Most of them were seen in the cerebellar cortex as fine varicose 5-HT3-positive axonal processes. 5-HT5A immunoreactivity, on the other hand, was observed in neuronal somata of the cerebellar cortex and deep cerebellar nuclei. Based upon cell morphology and the use of cell-specific markers, Purkinje cells, molecular layer interneurons and Golgi cells were found to be 5-HT5A immunopositive. In addition, the use of cell-specific markers allowed us to identify previously reported large 5-HT2A-positive cells in the granular layer as being Golgi cells. Finally, 5-HT7 immunoreactivity was observed only in Purkinje cells. Corroborating previous radioligand-binding, in situ hybridization and immunohistochemical studies, our data relate serotonin receptor subtypes to specific cerebellar cell types and may consequently contribute to the elucidation of serotonergic actions in the cerebellum. 相似文献
89.
Tim J.A. Hutten Wieger J. Norde Rob Woestenenk Ruo Chen Wang Frans Maas Michel Kester J.H. Frederik Falkenburg Sofia Berglund Leo Luznik Joop H. Jansen Nicolaas Schaap Harry Dolstra Willemijn Hobo 《Biology of blood and marrow transplantation》2018,24(4):666-677
Allogeneic stem cell transplantation (allo-SCT) can be a curative treatment for patients with a hematologic malignancy due to alloreactive T cell responses recognizing minor histocompatibility antigens (MiHA). Yet tumor immune escape mechanisms can cause failure of T cell immunity, leading to relapse. Tumor cells display low expression of costimulatory molecules and can up-regulate coinhibitory molecules that inhibit T cell functionality on ligation with their counter-receptors on the tumor-reactive T cells. The aim of this explorative study was to evaluate immune checkpoint expression profiles on T cell subsets and on cytomegalovirus (CMV)- and/or MiHA-reactive CD8+ T cells of allo-SCT recipients using a 13-color flow cytometry panel, and to correlate these expression patterns to clinical outcomes. MiHA-reactive CD8+ T cells exhibited an early differentiated CD27++/CD28++ phenotype with low KLRG-1 and CD57 expression. These T cells also displayed increased expression of PD-1, TIM-3, and TIGIT compared with total effector memory T cells and CMV-specific CD8+ T cells in healthy donors and allo-SCT recipients. Remarkably, high coexpression of PD-1, TIGIT, and KLRG-1 on MiHA-reactive CD8+ T cells was associated with relapse after allo-SCT. Taken together, these findings indicate that MiHA-specific CD8+ T cells of relapsed patients have a distinctive coinhibitory expression signature compared with patients who stay in remission. This phenotype may serve as a potential monitoring tool in patients. Moreover, these findings suggest that PD-1 and TIGIT play important roles in regulating T cell-mediated tumor control, providing a rationale for immunotherapy with blocking antibodies to treat relapse after allo-SCT. 相似文献
90.
TET2 mutations in cytogenetically normal acute myeloid leukemia: Clinical implications and evolutionary patterns 下载免费PDF全文
Frederik Damm Birgit Markus Felicitas Thol Michael Morgan Gudrun Göhring Brigitte Schlegelberger Jürgen Krauter Michael Heuser Olivier A. Bernard Arnold Ganser 《Genes, chromosomes & cancer》2014,53(10):824-832
Mutations of the Ten‐Eleven‐Translocation 2 (TET2) gene have been identified in patients with various myeloid neoplasms, but the clinical relevance of these mutations and their timing during disease development in cytogenetically normal acute myeloid leukemia (CN‐AML) remain unclear. The total coding region of TET2 was analyzed by direct sequencing in 215 CN‐AML patients younger than 60 years from multicenter treatment trials AML‐SHG 0199 (ClinicalTrials Identifier NCT00209833) and 0295. Associations were analyzed in the context of other molecular markers, such as CEBPA, DNMT3A, NMP1, FLT3, IDH1/2, RAS, and WT1. To investigate the order of appearance of TET2 and concomitant mutations, targeted deep resequencing was performed in six patients. At least one sequence variation with impact on TET2 protein sequence was found in 13 of the 215 CN‐AML patients (6%). Patients with TET2 mutations tended to be older (P = 0.078) and had higher platelet counts (P = 0.041). TET2‐mutated patients were more likely to have concomitant NPM1 (11 of 13; P = 0.047) and DNMT3A (10 of 13; P = 0.001) mutations but were mutually exclusive to partial tandem duplication of the MLL gene (MLL‐PTD) and IDH1/2 mutations. TET2 mutations were identified as subclones in four of the six investigated patients by deep sequencing. Progenitor‐derived colony assays suggest a stepwise acquisition of mutations during disease development, TET2 mutation being later than NPM1 and DNMT3A. The TET2 mutation status did not influence overall or relapse‐free survival. © 2014 Wiley Periodicals, Inc. 相似文献