全文获取类型
收费全文 | 2787篇 |
免费 | 163篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 101篇 |
妇产科学 | 43篇 |
基础医学 | 444篇 |
口腔科学 | 25篇 |
临床医学 | 271篇 |
内科学 | 473篇 |
皮肤病学 | 75篇 |
神经病学 | 365篇 |
特种医学 | 103篇 |
外科学 | 194篇 |
综合类 | 6篇 |
预防医学 | 251篇 |
眼科学 | 62篇 |
药学 | 233篇 |
中国医学 | 9篇 |
肿瘤学 | 287篇 |
出版年
2023年 | 15篇 |
2022年 | 45篇 |
2021年 | 63篇 |
2020年 | 54篇 |
2019年 | 42篇 |
2018年 | 71篇 |
2017年 | 50篇 |
2016年 | 66篇 |
2015年 | 74篇 |
2014年 | 115篇 |
2013年 | 128篇 |
2012年 | 197篇 |
2011年 | 209篇 |
2010年 | 163篇 |
2009年 | 132篇 |
2008年 | 178篇 |
2007年 | 188篇 |
2006年 | 215篇 |
2005年 | 171篇 |
2004年 | 146篇 |
2003年 | 151篇 |
2002年 | 151篇 |
2001年 | 25篇 |
2000年 | 24篇 |
1999年 | 22篇 |
1998年 | 31篇 |
1997年 | 40篇 |
1996年 | 21篇 |
1995年 | 22篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 8篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1972年 | 3篇 |
1969年 | 2篇 |
排序方式: 共有2955条查询结果,搜索用时 15 毫秒
21.
Induction of human airway smooth muscle apoptosis by neutrophils and neutrophil elastase 总被引:2,自引:0,他引:2
Oltmanns U Sukkar MB Xie S John M Chung KF 《American journal of respiratory cell and molecular biology》2005,32(4):334-341
Neutrophils are an important component of airway inflammation and may interact with human airway smooth muscle cells (HASMC). We investigated the effect of neutrophils and of neutrophil-derived proteases on HASMC survival. When co-incubated with neutrophils (0.1-1 x 10(6) cells/ml), attachment of human ASMC was reduced to 12.3 +/- 4.3% compared with untreated controls after 72 h. HASMC showed nuclear condensation and fragmentation (41.6 +/- 8.1% compared with baseline of 3.1 +/- 0.4%), and the biochemical markers of apoptosis, annexin V binding (9.7 +/- 0.7%; baseline 1.1 +/- 0.3%) and cleaved caspase-3 expression, were observed. The proteolytic activity released by neutrophils was essential for the proapoptotic effect because inhibition of elastase activity by alpha(1)-antitrypsin and MeOSuc-Ala-Ala-Pro-Ala-CMK (MSACK) reduced HASMC apoptosis. Human neutrophil elastase (0.1-3 microg/ml) induced apoptosis of HASMC, as well as other neutrophil serine proteases, cathepsin G, and proteinase 3. Fibronectin degradation products were present in HASMC supernatants exposed to neutrophil-conditioned media and to neutrophil elastase. The local release of proteases from neutrophils present in airway smooth muscle cells may lead to HASMC apoptosis as a result of matrix degradation and loss of cell attachment. This may limit pathologic changes such as ASMC hyperplasia and extracellular matrix deposition seen in airway remodeling. 相似文献
22.
Transgenic rat model of Huntington's disease 总被引:12,自引:0,他引:12
von Hörsten S Schmitt I Nguyen HP Holzmann C Schmidt T Walther T Bader M Pabst R Kobbe P Krotova J Stiller D Kask A Vaarmann A Rathke-Hartlieb S Schulz JB Grasshoff U Bauer I Vieira-Saecker AM Paul M Jones L Lindenberg KS Landwehrmeyer B Bauer A Li XJ Riess O 《Human molecular genetics》2003,12(6):617-624
Huntington's disease (HD) is a late manifesting neurodegenerative disorder in humans caused by an expansion of a CAG trinucleotide repeat of more than 39 units in a gene of unknown function. Several mouse models have been reported which show rapid progression of a phenotype leading to death within 3-5 months (transgenic models) resembling the rare juvenile course of HD (Westphal variant) or which do not present with any symptoms (knock-in mice). Owing to the small size of the brain, mice are not suitable for repetitive in vivo imaging studies. Also, rapid progression of the disease in the transgenic models limits their usefulness for neurotransplantation. We therefore generated a rat model transgenic of HD, which carries a truncated huntingtin cDNA fragment with 51 CAG repeats under control of the native rat huntingtin promoter. This is the first transgenic rat model of a neurodegenerative disorder of the brain. These rats exhibit adult-onset neurological phenotypes with reduced anxiety, cognitive impairments, and slowly progressive motor dysfunction as well as typical histopathological alterations in the form of neuronal nuclear inclusions in the brain. As in HD patients, in vivo imaging demonstrates striatal shrinkage in magnetic resonance images and a reduced brain glucose metabolism in high-resolution fluor-deoxy-glucose positron emission tomography studies. This model allows longitudinal in vivo imaging studies and is therefore ideally suited for the evaluation of novel therapeutic approaches such as neurotransplantation. 相似文献
23.
Leukotriene and prostaglandin production by mouse peritoneal macrophages was investigated. It could be shown that the tumour promoter 12-O-tetradecanoylphorbol-13-acetate initiated the release of prostaglandin E2 but had little effect on the release of leukotriene C4-like immunoreactivity. The divalent cation ionophore A 23187 at concentrations between 10–6 and 10–8 mol/l initiated prostaglandin as well as leukotriene release. This prostaglandin and leukotriene release could be modulated by drugs. Non-steroidal anti-inflammatory drugs including benoxaprofen inhibited prostaglandin release but simultaneously enhanced leukotriene production. The analgesics paracetamol and 4-methylaminoantipyrine had similar effects at high concentrations. The experimental compound BW 755 c inhibited prostaglandin and leukotriene production while the antithrombotic compound nafazatrom inhibited the production of leukotriene C4-like immunoreactivity but enhanced prostaglandin E2 production. Nordihydroguaiaretic acid inhibited prostaglandin and leukotriene production. The results show that the metabolism of arachidonic acid in macrophages via the cyclooxygenase or the lipoxygenase pathway is dependent on the stimulus applied. Both pathways can be inhibited conjointly or selectively by drugs. Our results do not provide evidence that differences in anti-inflammatory activity claimed for some of the drugs tested can be explained by differential inhibition of either pathway. The experimental system described may be used for assessing the potency of drugs to inhibit the lipoxygenase and the cyclooxygenase pathway of arachidonic acid metabolism. 相似文献
24.
Vitamin D food fortification in European countries: the underused potential to prevent cancer deaths
Niedermaier Tobias Gredner Thomas Kuznia Sabine Schöttker Ben Mons Ute Lakerveld Jeroen Ahrens Wolfgang Brenner Hermann 《European journal of epidemiology》2022,37(4):309-320
European Journal of Epidemiology - Background: Meta-analyses of randomized controlled trials have shown that vitamin D supplementation reduces cancer mortality by 13%. Vitamin D fortification of... 相似文献
25.
Carolin Lepa Sascha Hoppe Antje Stber Boris V. Skryabin Laura Katharina Sievers Barbara Heitplatz Giuliano Ciarimboli Ute Neugebauer Maja T. Lindenmeyer Clemens D. Cohen Hannes C.A. Drexler Peter Boor Thomas Weide Hermann Pavenstdt Britta George 《Journal of the American Society of Nephrology : JASN》2021,32(2):357
BackgroundInjury to kidney podocytes often results in chronic glomerular disease and consecutive nephron malfunction. For most glomerular diseases, targeted therapies are lacking. Thus, it is important to identify novel signaling pathways contributing to glomerular disease. Neurotrophic tyrosine kinase receptor 3 (TrkC) is expressed in podocytes and the protein transmits signals to the podocyte actin cytoskeleton.MethodsNephron-specific TrkC knockout (TrkC-KO) and nephron-specific TrkC-overexpressing (TrkC-OE) mice were generated to dissect the role of TrkC in nephron development and maintenance.ResultsBoth TrkC-KO and TrkC-OE mice exhibited enlarged glomeruli, mesangial proliferation, basement membrane thickening, albuminuria, podocyte loss, and aspects of FSGS during aging. Igf1 receptor (Igf1R)–associated gene expression was dysregulated in TrkC-KO mouse glomeruli. Phosphoproteins associated with insulin, erb-b2 receptor tyrosine kinase (Erbb), and Toll-like receptor signaling were enriched in lysates of podocytes treated with the TrkC ligand neurotrophin-3 (Nt-3). Activation of TrkC by Nt-3 resulted in phosphorylation of the Igf1R on activating tyrosine residues in podocytes. Igf1R phosphorylation was increased in TrkC-OE mouse kidneys while it was decreased in TrkC-KO kidneys. Furthermore, TrkC expression was elevated in glomerular tissue of patients with diabetic kidney disease compared with control glomerular tissue.ConclusionsOur results show that TrkC is essential for maintaining glomerular integrity. Furthermore, TrkC modulates Igf-related signaling in podocytes. 相似文献
26.
Schmitz Timo Meisinger Christa Kirchberger Inge Thilo Christian Amann Ute Baumeister Sebastian E. Linseisen Jakob 《European journal of epidemiology》2021,36(6):619-627
European Journal of Epidemiology - The aim of this study was to evaluate the impact of the COVID-19 pandemic lockdown on acute myocardial infarction (AMI) care, and to identify underlying stressors... 相似文献
27.
Ulrich Mußhoff Michael Madeja Norbert Binding Ute Witting Erwin-Josef Speckmann 《Naunyn-Schmiedeberg's archives of pharmacology》1995,353(1):42-45
The effects of bivalent lead on ion channels activated by kainate and -amino-3-hydroxy-5-methyl-4-isoxazolpropionate (AMPA) were studied using Xenopus oocytes microinjected with mRNA from rat brain. Lead reduced kainate-induced membrane currents in a reversible and dose-dependent manner, without affecting membrane currents induced by AMPA. Lead decreased the kainate currents with a concentration of 0.1 mol/l to 0.93 ± 0.01 and with a concentration of 100 mol/l to 0.41 ± 0.04 of the control values. The blocking effect of lead on kainate responses was voltage dependent. The inhibition was strongest at - 90 mV to - 70 mV and became weaker at more positive membrane potentials. The effect of lead on the kainate-induced membrane currents remained unchanged when the concentration of kainate was increased. Hence lead probably represents a noncompetitive channel-blocking agent for non-N-methyl-d-aspartate (NMDA) receptor channels activated by kainate. 相似文献
28.
Neurodevelopmental disorders in males related to the gene causing Rett syndrome in females (MECP2). 总被引:2,自引:0,他引:2
Ute Moog Eric E J Smeets Kees E P van Roozendaal Sam Schoenmakers Jos Herbergs Anneke M J Schoonbrood-Lenssen Connie T R M Schrander-Stumpel 《European journal of paediatric neurology》2003,7(1):5-12
Mutations in the MECP2 (methyl-CpG-binding protein 2) gene are known to cause Rett syndrome, a well-known and clinically defined neurodevelopmental disorder. Rett syndrome occurs almost exclusively in females and for a long time was thought to be an X-linked dominant condition lethal in hemizygous males. Since the discovery of the MECP2 gene as the cause of Rett syndrome in 1999, MECP2 mutations have, however, also been reported in males. These males phenotypically have classical Rett syndrome when the mutation arises as somatic mosaicism or when they have an extra X chromosome. In all other cases, males with MECP2 mutations show diverse phenotypes different from classical Rett syndrome. The spectrum ranges from severe congenital encephalopathy, mental retardation with various neurological symptoms, occasionally in association with psychiatric illness, to mild mental retardation only. We present a 21-year-old male with severe mental retardation, spastic tetraplegia, dystonia, apraxia and neurogenic scoliosis. A history of early hypotonia evolving into severe spasticity, slowing of head growth, breathing irregularities and good visual interactive behaviour were highly suggestive of Rett syndrome. He has a de novo missense mutation in exon 3 of the MECP2 gene (P225L). The clinical spectrum and molecular findings in males with MECP2 mutations are reviewed. 相似文献
29.
Elevated expression of carcinoembryonic antigen-related cell adhesion molecule 1 promotes progression of non-small cell lung cancer. 总被引:7,自引:0,他引:7
Wulf Sienel Sebastian Dango Ute Woelfle Alicia Morresi-Hauf Christoph Wagener Jens Brümmer Wolf Mutschler Bernward Passlick Klaus Pantel 《Clinical cancer research》2003,9(6):2260-2266
PURPOSE: Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM-1) has recently been implicated in cancer development and progression. This study was performed to assess whether CEACAM-1 expression in primary tumors is correlated to long-term survival in patients with operable non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: Primary tumors of 145 consecutive patients with completely resected NSCLC (pT(1-4) pN(0-2) M(0) R(0)) were stained immunohistochemically using the monoclonal anti-CEACAM-1 antibody 4D1/C2. The prognostic relevance of CEACAM-1 expression was evaluated by univariate Kaplan-Meier and multivariate Cox regression analysis. The median follow-up period was 72 months (range, 10-130 months). RESULTS: Normal bronchiolar epithelium present in all sections exhibited no immunostaining. In contrast, 73 tumors (50.4%) showed between 1 and 66% CEACAM-1 positive tumor cells, and 72 tumors (49.6%) exhibited even a higher percentage of positive tumor cells. A high CEACAM-1 expression rate (i.e., >/=66% positive tumor cells) was more frequent in adenocarcinomas than in squamous cell carcinomas (61.9 versus 35.7%, respectively). Multivariate Cox regression analysis demonstrated that CEACAM-1 represents an independent prognosticator for cancer-related survival (P = 0.018; relative risk, 1.8; 95% confidence interval, 1.1-2.8). Subgroup analysis revealed that a high CEACAM-1 expression rate was of significant prognostic impact in pN(1)-pN(2) patients (n = 60; P = 0.024), pT(3)-pT(4) patients (n = 22; P = 0.009), and stage IIa-IIIa patients (n = 69; P = 0.012). CONCLUSIONS: The absence of CEACAM-1 in normal lung tissue and its expression in tumor cells argues against a tumor-suppressive role of CEACAM-1 in NSCLC. The correlation between elevated CEACAM-1 expression and an unfavorable prognosis indicates rather that CEACAM-1 might promote lung cancer progression. 相似文献
30.
Datenschutz innerhalb des länderübergreifenden Deutschen Zentralregisters für kindliche Hörstörungen
Zusammenfassung
Das Deutsche Zentralregister für kindliche H?rst?rungen (DZH) verarbeitet bundesweit Daten von verschiedenen audiologischen
Einrichtungen. Die Bew?ltigung der anfallenden Datenmengen, die nachfolgende Datenverwaltung und -analyse erfordern neben
einer differenzierten und kontrollierbaren Verarbeitung ein H?chstma? an Datensicherheit. Vor allem die l?nderübergreifende
Struktur eines Registers erfordert schon bei der Planung engste Zusammenarbeit mit dem zust?ndigen Landesdatenschutzbeauftragten
und auch mit den Landesdatenschutzbeauftragten anderer beteiligter Bundesl?nder. Am Beispiel des DZH wird demonstriert, wie
eine kooperative Zusammenarbeit pragmatisch realisiert werden kann. Besonderheiten bei der Datenerhebung, Datentransfer, Speicherung
und L?schung von Daten, technische Datenschutzma?nahmen, Sicherstellung von Anonymit?t durch Codierungsstrategien, Duplikatsprüfung,
Datentrennung und automatisierte Datenauswertung werden an Beispielen erl?utert.
Eingegangen am 13. August 1997 Angenommen am 18. Dezember 1997 相似文献