全文获取类型
收费全文 | 2078篇 |
免费 | 131篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 117篇 |
妇产科学 | 124篇 |
基础医学 | 308篇 |
口腔科学 | 39篇 |
临床医学 | 226篇 |
内科学 | 496篇 |
皮肤病学 | 45篇 |
神经病学 | 71篇 |
特种医学 | 27篇 |
外科学 | 233篇 |
综合类 | 11篇 |
预防医学 | 156篇 |
眼科学 | 23篇 |
药学 | 162篇 |
中国医学 | 3篇 |
肿瘤学 | 168篇 |
出版年
2023年 | 6篇 |
2022年 | 15篇 |
2021年 | 37篇 |
2020年 | 16篇 |
2019年 | 23篇 |
2018年 | 24篇 |
2017年 | 28篇 |
2016年 | 53篇 |
2015年 | 49篇 |
2014年 | 65篇 |
2013年 | 80篇 |
2012年 | 105篇 |
2011年 | 129篇 |
2010年 | 72篇 |
2009年 | 70篇 |
2008年 | 124篇 |
2007年 | 116篇 |
2006年 | 122篇 |
2005年 | 103篇 |
2004年 | 112篇 |
2003年 | 118篇 |
2002年 | 101篇 |
2001年 | 38篇 |
2000年 | 47篇 |
1999年 | 44篇 |
1998年 | 34篇 |
1997年 | 32篇 |
1996年 | 20篇 |
1995年 | 29篇 |
1994年 | 22篇 |
1993年 | 27篇 |
1992年 | 34篇 |
1991年 | 30篇 |
1990年 | 29篇 |
1989年 | 22篇 |
1988年 | 21篇 |
1987年 | 10篇 |
1986年 | 19篇 |
1985年 | 25篇 |
1984年 | 22篇 |
1983年 | 11篇 |
1982年 | 14篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1975年 | 6篇 |
1974年 | 9篇 |
1971年 | 6篇 |
1970年 | 5篇 |
1969年 | 10篇 |
1968年 | 8篇 |
排序方式: 共有2214条查询结果,搜索用时 0 毫秒
81.
Zimmermann AK Aebert H Reiz A Freitag M Husseini M Ziemer G Wendel HP 《ASAIO journal (American Society for Artificial Internal Organs : 1992)》2004,50(3):193-199
An inflammatory response to cardiopulmonary bypass (CPB) caused by bioincompatibility of extracorporeal circuits is one of the major clinical issues in cardiac surgery. Recently a new coating material, poly-2-methoxyethylacrylate (PMEA), was developed to improve the biocompatibility of blood contacting surfaces. In a simulated cardiopulmonary bypass model, using fresh human whole blood, 15 membrane oxygenators (Capiox SX18, Terumo Corp., Tokyo, Japan) were compared. Five of them had the PMEA coating, five had a heparin-coated surface, and five had no surface treatment. Blood samples were taken at several time-points during a 90 minute circulation period. Changes in coagulation, complement, and blood cell alteration factors were measured by ELISA methods, plasma bradykinin levels were measured by radioimmunoassay, and expression of genes encoding cytokines TNF-alpha, interleukin-1beta, interleukin-6, and interleukin-8 was determined by semiquantitative real time RT-PCR. Platelet adhesion was significantly reduced in both the PMEA and the heparin coated circuits. Release of platelet activation marker beta-thromboglobulin was significantly higher in the uncoated control group (p < 0.01). After 5 minutes of blood circulation bradykinin levels significantly increased in all three groups (p < 0.01); however, the group with the PMEA coated oxygenators showed the lowest values. Expression of genes encoding proinflammatory cytokines in monocytes was increased in all groups, with the lowest being in the PMEA coated group. PMEA coated CPB surfaces in an in vitro experimental model showed an improved thrombogenicity, reduced bradykinin release, less platelet activation and less proinflammatory cytokines gene expression in comparison with a noncoated group. The authors assume that PMEA coating may ameliorate some of intra- and postperfusion syndromes, particularly hypotension, unspecific inflammation, hyperfibrinolysis, and blood loss. 相似文献
82.
Tancredi M Sensi E Cipollini G Aretini P Lombardi G Di Cristofano C Presciuttini S Bevilacqua G Caligo MA 《European journal of human genetics : EJHG》2004,12(9):775-777
Germ-line mutations in the BRCA1 gene cause hereditary predisposition to breast and ovarian cancer. BRCA1 and BRCA2 mutations account for about 40% of high-risk families. Mutation-screening methods generally focus on genomic DNA and are usually PCR based; they enable the detection of sequence alterations such as point mutations and small deletions and insertions. However, they do not allow the detection of partial or entire exon(s) loss, because the presence of the homologous allele results in a positive PCR signal, giving rise to a false-negative result. Identification of unusual haplotypes in patient samples by an expectation maximization algorithm has recently been suggested as a method for identifying hemizygous regions caused by large intragenic deletions. Using a similar approach, we identified a novel BRCA1 genomic rearrangement in a breast/ovarian cancer family negative at the first mutation screening; we detected a deletion encompassing exons 14-19, probably due to replication slippage between Alu sequences. 相似文献
83.
Age dependence of endogenous galactose formation in Q188R homozygous galactosemic patients 总被引:4,自引:0,他引:4
The age dependence of endogenous galactose formation was investigated in Q188R homozygous galactosemic patients (n=18; 4-38 years) using the primed continuous infusion approach with D-[1-13C]galactose as a substrate. Studies were conducted under postabsorptive conditions (fasting >10h) and good metabolic control. In the patients, the release of galactose from endogenous sources into plasma (R(a)) decreased with age and ranged from 4.6 to 2.0 micromol/kg body weight per h. Galactitol and galactonate release rates paralleled the galactose R(a) but at a lower level. The mean relation of galactose, galactitol, and galactonate release was 10:5:1. Statistically, there was a highly significant (p<0.0001) inverse correlation between total galactose release (i.e., sum of R(a) plus galactitol and galactonate release) and age. The data (total galactose=y, age=t) were best fitted to the simple exponential model y=y(0)+axexp(-bt) by non-linear regression analysis. The parameter estimates were y(0)=3.0+/-0.2, a=6.5+/-0.4, and b=0.11+/-0.02. The value of y(0) provides an estimate of total galactose release in adult patients (i.e., approximately 13 mg/kg body weight per day), summation operator (y(0)+a) provides an estimate for galactosemic newborns (i.e., approximately 41 mg/kg body weight per day). The data show that significant amounts of endogenous galactose are formed in galactosemic patients with release rates being several fold higher in infants than in adults. The present findings can explain the persistently elevated galactose-1-phosphate levels in erythrocytes-and its age dependence-in galactosemic patients even when under strict dietary treatment. 相似文献
84.
Furtado RA Rodrigues EP Araújo FR Oliveira WL Furtado MA Castro MB Cunha WR Tavares DC 《Toxicologic pathology》2008,36(4):576-580
Ursolic acid (UA) and oleanolic acid (OA) are pentacyclic triterpenoid compounds found in plants used in the human diet and in medicinal herbs, in the form of aglycones or as the free acid. These compounds are known for their hepatoprotective, anti-inflammatory, antimicrobial, hypoglycemic, antimutagenic, antioxidant, and antifertility activities. In the present study, we evaluated the effects of UA and OA on the formation of 1,2-dimethyl-hydrazine (DMH)-induced aberrant crypt foci (ACF) in the colon of the male Wistar rat. The animals received subcutaneous (sc) injections of DMH (40 mg/kg body weight) twice a week for two weeks to induce ACF. UA, OA and a mixture of UA and OA were administered to the rats five times a week for four weeks by gavage at doses of 25 mg/kg body weight/day each, during and after DMH treatment. All animals were sacrificed in week 5 for the evaluation of ACF. The results showed a significant reduction in the frequency of ACF in the group treated with the triterpenoid compounds plus DMH when compared to those treated with DMH alone, suggesting that UA and OA suppress the formation of ACF and have a protective effect against colon carcinogenesis. 相似文献
85.
Brian M. Wendel Suzanne Hollingsworth Charmain T. Courcelle Justin Courcelle 《Genes to cells : devoted to molecular & cellular mechanisms》2021,26(2):94-108
Replication initiation, elongation and completion are tightly coordinated to ensure that all sequences replicate precisely once each generation. UV-induced DNA damage disrupts replication and delays elongation, which may compromise this coordination leading to genome instability and cell death. Here, we profiled the Escherichia coli genome as it recovers from UV irradiation to determine how these replicational processes respond. We show that oriC initiations continue to occur, leading to copy number enrichments in this region. At late times, the combination of new oriC initiations and delayed elongating forks converging in the terminus appear to stress or impair the completion reaction, leading to a transient over-replication in this region of the chromosome. In mutants impaired for restoring elongation, including recA, recF and uvrA, the genome degrades or remains static, suggesting that cell death occurs early after replication is disrupted, leaving partially duplicated genomes. In mutants impaired for completing replication, including recBC, sbcCD xonA and recG, the recovery of elongation and initiation leads to a bottleneck, where the nonterminus region of the genome is amplified and accumulates, indicating that a delayed cell death occurs in these mutants, likely resulting from mis-segregation of unbalanced or unresolved chromosomes when cells divide. 相似文献
86.
Monica D. Levine Jubilee Brown Erin K. Crane David L. Tait R. Wendel Naumann 《Journal of minimally invasive gynecology》2021,28(4):824-828
Study ObjectiveTo compare outcomes after minimally invasive surgery (MIS) vs open radical hysterectomy for early stage cervical cancer incorporating 2018 Federation of Gynecology and Obstetrics (FIGO) staging.DesignA retrospective analysis.SettingA single teaching hospital.PatientsPatients after radical hysterectomy for stage IA1 with lymphovascular invasion, IA2, or IB1 squamous, adenosquamous, or adenocarcinoma of the cervix between 2007 and 2018, mirroring the Laparoscopic Approach to Cervical Cancer trial criteria.InterventionsThe use of MIS surgery for performing radical hysterectomy.Measurements and Main ResultsThe outcomes were compared between patients undergoing MIS vs open approaches. A total of 126 patients met the inclusion criteria. The approach was open in 44 patients (35%) and MIS in 82 patients (65%); 49% were laparoscopic and 51% were robotic. Distribution based on the 2009 FIGO staging showed 1 stage IA1 with lymphovascular invasion, 15 stage IA2, and 110 stage IB1 patients. Although not statistically significant, the 3-year disease-free survival (DFS) was higher in the open compared to the MIS group (95% vs 87%; p = .17), and the overall survival was higher in the open compared to the MIS group (97% vs 92%; p = .25).Fourteen patients whose disease recurred were Stage IB1 by FIGO 2009 staging; 11/14 were reclassified to a higher stage by 2018 FIGO staging (5/5 open, 6/9 MIS). Adjuvant therapy was recommended for all these patients based on the Sedlis criteria (10/14) or other risk factors (4/14). Despite this, only 1/9 of MIS patients whose disease recurred received adjuvant therapy compared with 3/5 patients whose disease recurred in the open group (p = .05).ConclusionIn a cohort of patients similar to that of the Laparoscopic Approach to Cervical Cancer trial, 2018 FIGO staging may be useful to refine indications for MIS radical hysterectomy in early stage cervical cancer. However, disparate outcomes between MIS and open approaches may be explained by differences in compliance with National Comprehensive Cancer Network guidelines for adjuvant therapy. 相似文献
87.
Recurrent NAB2–STAT6 gene fusions and oestrogen receptor‐α expression in pulmonary adenofibromas 下载免费PDF全文
Nicola Fusco Elena Guerini‐Rocco Claudia Augello Andrea Terrasi Giulia Ercoli Caterina Fumagalli Davide Vacirca Paola Braidotti Antonina Parafioriti Marta Jaconi Letterio Runza Vijayalakshmi Ananthanarayanan Fabio Pagni Silvano Bosari Massimo Barberis Stefano Ferrero 《Histopathology》2017,70(6):906-917
88.
Mentel R Bordihn N Wegner U Wendel H Niklasson B 《Medical microbiology and immunology》1999,188(1):51-53
Dobrava virus infection was diagnosed serologically by enzyme-linked immunosorbent and immunofluorescence assays. To determine
which hantavirus serotype was involved, sera were analyzed by a focus reduction neutralization test. The clinical data indicated
that only pulmonary manifestation was present. Our data support the presence of Dobrava virus infection outside the Balkan
region. In conclusion, a previously healthy adult with unexplained pulmonary perfusion failure should be investigated for
hantavirus infection.
Received: 15 March 1999 相似文献
89.
Dendritic cell-endothelial cell cross-talk in angiogenesis 总被引:1,自引:0,他引:1
Dendritic cells (DCs) are professional antigen-presenting cells that have a pivotal role in the onset and regulation of adaptive immune responses. DCs have the ability to regulate inflammation through their capacity to release cytokines and chemokines and kill pathogens, which they share with other phagocytes. Recent observations have shown that different DC subsets produce and release various pro- and anti-angiogenic mediators depending on their activation status and cytokine milieu. In particular, alternatively activated DCs exert a potent pro-angiogenic activity that is mediated by the prototypic angiogenic growth factor vascular endothelial growth factor-A (VEGF-A). In turn, pro- and anti-angiogenic mediators can affect the biology of DCs, modulating their differentiation and maturation. Finally, DCs can trans-differentiate into endothelial-like cells, possibly contributing to vasculogenesis in the adult. Thus, DCs might exert an important impact on the neovascularization process in different physiopathological conditions. 相似文献
90.