全文获取类型
收费全文 | 459篇 |
免费 | 29篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 11篇 |
妇产科学 | 9篇 |
基础医学 | 103篇 |
口腔科学 | 9篇 |
临床医学 | 30篇 |
内科学 | 81篇 |
皮肤病学 | 10篇 |
神经病学 | 42篇 |
特种医学 | 6篇 |
外科学 | 21篇 |
综合类 | 5篇 |
预防医学 | 31篇 |
眼科学 | 28篇 |
药学 | 52篇 |
中国医学 | 11篇 |
肿瘤学 | 39篇 |
出版年
2024年 | 1篇 |
2023年 | 10篇 |
2022年 | 5篇 |
2021年 | 11篇 |
2020年 | 4篇 |
2019年 | 9篇 |
2018年 | 16篇 |
2017年 | 12篇 |
2016年 | 12篇 |
2015年 | 16篇 |
2014年 | 16篇 |
2013年 | 31篇 |
2012年 | 38篇 |
2011年 | 36篇 |
2010年 | 26篇 |
2009年 | 18篇 |
2008年 | 35篇 |
2007年 | 34篇 |
2006年 | 31篇 |
2005年 | 23篇 |
2004年 | 32篇 |
2003年 | 19篇 |
2002年 | 24篇 |
2001年 | 3篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1996年 | 2篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 2篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1965年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有489条查询结果,搜索用时 0 毫秒
1.
Robert Estes Daniel Estes Constance West Jitka Zobal-Ratner Patrick Droster John Simon 《Journal of AAPOS》2007,11(4):325-329
PURPOSE: To describe data sources and functional utility of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) workforce database and associated map files. METHODS: Population data from the 2000 U.S. Census and current listings from the AAPOS and American Academy of Ophthalmology (AAO) databases were organized to demonstrate and analyze practitioner-to-population relationships for metropolitan statistical areas nationwide. An interactive map was developed to provide an intuitive graphical display of the data. RESULTS: A total of 749 active AAPOS members were distributed in 154 of 280 defined metropolitan statistical areas. Within these areas, a 0- to 20-year age subgroup varied from 17.8% to 42.6%, with an average of 30.4%. The AAPOS member-to-million-person ratio varied from 1.3 to 27, with higher numbers generally representing regions with population bases inadequately defined by Census Bureau statistical area definitions. Ratios for a majority of larger, better-defined areas ranged from 3 to 4 AAPOS members per million persons. Sizable areas with no AAPOS member presence were identified and tabulated. AAO members with a specified pediatric practice focus who were not AAPOS members were identified in 103 areas, possibly influencing patient choices and practitioner referrals for these regions. CONCLUSIONS: The AAPOS workforce database and related interactive map display practitioner and population data that may assist physicians and planners in targeting practice development and identifying potentially underserved areas. 相似文献
2.
The effect of single and repeated UVB radiation on rabbit cornea 总被引:1,自引:0,他引:1
Miroslav Fris May-Britt Tessem Jitka Čejková Anna Midelfart 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2006,244(12):1680-1687
Background Cumulative effect of ultraviolet radiation (UVR) is an important aspect of UV corneal damage. The purpose of this study was to apply high resolution magic angle spinning proton nuclear magnetic resonance (HR-MAS 1H NMR) spectroscopy to evaluate the effect of single and repeated UV radiation exposure of the same overall dose on the rabbit cornea.Methods Corneal surfaces of 24 normal rabbit eyes were examined for the effects of UVB exposure (312 nm). In the first group (UVB1), animals were irradiated with a single dose (3.12 J/cm2; 21 min) of UVB radiation. The animals in the second group (UVB2) were irradiated three times for 7 min every other day (dose of 1.04 J/cm2; days 1, 3, 5) to give the same overall dose (3.12 J/cm2). The third group served as an untreated control group. One day after the last irradiation, the animals were sacrificed, and the corneas were removed and frozen. HR-MAS 1H NMR spectra from intact corneas were obtained. Special grouping patterns among the tissue samples and the relative percentage changes in particular metabolite concentrations were evaluated using modern statistical methods (multivariate analysis, one-way ANOVA).Results The metabolic profile of both groups of UVB-irradiated samples was significantly different from the control corneas. Substantial decreases in taurine, hypo-taurine and choline-derivatives concentrations and substantial elevation in glucose and betaine levels were observed following the UVR exposure. There was no significant difference between the effect of a single and repeated UVB irradiation of the same overall dose.Conclusions For the first time, the effects of single and repeated UVR doses on the metabolic profile of the rabbit cornea were analysed and compared. The combination of HR-MAS 1H NMR spectroscopy and modern statistical methods (multivariate analysis, one-way ANOVA) proved suitable to assess the overall view of the metabolic alterations in the rabbit corneal tissue following UVB radiation exposure. 相似文献
3.
Cytokines and adhesion molecules in renal vasculitis and lupus nephritis 总被引:20,自引:1,他引:19
Tesar V; Masek Z; Rychlik I; Merta M; Bartunkova J; Stejskalova A; Zabka J; Janatkova I; Fucikova T; Dostal C; Becvar R 《Nephrology, dialysis, transplantation》1998,13(7):1662-1667
Background: Plasma levels of some pro-inflammatory
cytokines and soluble adhesion molecules have been suggested to be useful
parameters to assess the activity of antineutrophil cytoplasmic antibody
(ANCA)-positive vasculitis and lupus nephritis. We hypothesized that the
renal activity of these diseases is better reflected by the urinary
excretion and fractional excretion of these molecules.
Methods: Plasma levels and urinary excretion of tumour
necrosis factor-&agr; (TNF-&agr;), interleukin (IL)-6, IL-8, and
the soluble cell adhesion molecules sICAM-1 and sVCAM-1 were measured by
enzyme-linked immunosorbent assay (ELISA) in 15 patients with ANCA-positive
renal vasculitis (eight active, ANCA-A; six in remission, ANCA-R), six
patients with active lupus nephritis (LN), 15 patients with IgA nephropathy
(IgAN) and nine healthy subjects. Fractional excretion of selected
cytokines and adhesion molecules was also calculated.
Results: Patients with ANCA-A had increased urinary
excretion and fractional excretion of TNF-&agr; (9.27±3.19%
vs 0.58±0.02%, P<0.01), IL-6
(120.79±65.83% vs 1.89±0.34%,
P<0.01) and increased fractional excretion of IL-8
(23.34±6.38% vs 2.56±1.07%,
P<0.01) and sVCAM-1 (0.81±0.33% vs
0.03±0.02%, P<0.01) compared with controls. Urinary
excretion of TNF-&agr; and IL-6 and fractional excretion of
TNF-&agr;, IL-6 and IL-8 were higher in ANCA-A than in ANCA-R. Patients
with LN had increased plasma TNF-&agr; (20.52±2.01 pg/ml
vs 12.33±0.23 pg/ml, P<0.05) and
sVCAM-1 (1537.88±276.36 ng/ml vs
692.26±44.42 ng/ml, P<0.05) and increased urinary
excretion of TNF-&agr; (2.81±0.51 &mgr;g/mol creat
vs 0.98±0.05 &mgr;g/mol creat,
P<0.01), IL-8 (35.78±14.03 &mgr;g/mol creat
vs 12.46±5.19 &mgr;g/mol creat,
P<0.05) and sVCAM-1 (48.98±20.20 &mgr;g/mol creat
vs 2.92±1.35 &mgr;g/mol creat,
P<0.01) compared with controls. Patients with IgAN had, in
comparison with controls only increased plasma TNF-&agr;
(18.10±0.57 pg/ml vs 12.33±0.23
pg/ml, P<0.05). Conclusions: Urinary excretion
and fractional excretion, but not plasma levels of selected proinflammatory
cytokines (TNF-&agr;, IL-6 and IL-8) were increased in patients with
active ANCA-positive renal vasculitis, but not in ANCA positive vasculitis
in remission. These parameters may be useful to monitor the activity of
this disease. 相似文献
4.
Antisense inhibition of methylenetetrahydrofolate reductase reduces cancer cell survival in vitro and tumor growth in vivo. 总被引:3,自引:0,他引:3
PURPOSE: Many cancer lines are methionine dependent and decrease proliferation when methionine supply is limited. Methylenetetrahydrofolate reductase (MTHFR) generates the folate derivative for homocysteine remethylation to methionine. We investigated the effect of antisense-mediated inhibition of MTHFR on survival of human cancer cells. EXPERIMENTAL DESIGN: We examined the in vitro and in vivo anticancer effects of a combination of MTHFR antisense and standard cytotoxic drugs. RESULTS: Specific antisense against MTHFR (EX5) showed significant inhibitory effects on growth of human colon, lung, breast, prostate, and neuroblastoma tumor cells in vitro compared with that of the control oligonucleotide. Cytotoxic drugs (5-fluorouracil, cisplatin, or paclitaxel) potentiated the effect of EX5. In vivo, antisense alone or in combination with cytotoxic drugs inhibited the growth of human colon and lung carcinoma xenografts. In comparison with control oligonucleotide, treatment with EX5 inhibited growth of colon tumors and lung tumors by 60% and 45%, respectively. EX5 with 5-fluorouracil decreased growth of colon tumors by an additional 30% compared with EX5 alone, and EX5 with cisplatin decreased growth of lung tumors by an additional 40% compared with cisplatin alone. Growth inhibition by EX5 was associated with decreased amounts of MTHFR protein and with increased amounts of an apoptosis marker. CONCLUSIONS: Our results confirm that MTHFR inhibition decreases tumor growth and suggest that inhibition of MTHFR by antisense or small molecules may be a novel anticancer approach. 相似文献
5.
Sanguinarine and chelerythrine: assessment of safety on pigs in ninety days feeding experiment. 总被引:4,自引:0,他引:4
Pavel Kosina Daniela Walterová Jitka Ulrichová Václav Lichnovsky Marie Stiborová Helena Rydlová Jaroslav Vicar Vladimír Krecman Michael J Brabec Vilím Simánek 《Food and chemical toxicology》2004,42(1):85-91
Sanguinaria canadesis, Chelidonium majus and Macleya cordata have been used for centuries as alternative medicines. Currently the extracts from these medicinal plants are components of veterinary and human phytopreparations, and of oral-hygiene agents. Sanguinarine and chelerythrine (SA/CHE) are biologically active components of these extracts. They display distinct antibacterial and anti-inflammatory properties, but, on the other hand, they have been reported as having adverse effects - genotoxicity and hepatotoxicity. This paper is aimed at evaluation of the effects of daily administration of the extract from Macleya cordata (2 mg and 100 mg in 1 kg feed, sanguinarine:chelerythrine 3:1) in the diet on the health status of swine. After 90-day administration, alkaloids were retained to a different extent in tissues. The highest SA/CHE retention was detected in the gingiva (0.55 microg/g) and liver (0.15 microg/g), no SA/CHE were detected in muscles. Plasma SA levels attained 0.11 microg/ml. Treated animals did not display any results of hematological, biochemical or histological assay different from controls. A (32)P-postlabeling assay proved that no DNA-adducts with SA/CHE were detected in pig livers. We did not observe any symptom linked to epidemic dropsy syndrome often attributed to sanguinarine. In conclusion, an average daily oral dose of alkaloids up to 5 mg per 1 kg animal body weight proved to be safe. 相似文献
6.
Psotová J Chlopcíková S Miketová P Hrbác J Simánek V 《Phytotherapy research : PTR》2004,18(7):516-521
Flavonoids are found universally in plants and act as free radical scavenging and chelating agents with antiinflammatory, antiischemic, vasodilating and chemoprotective properties. In this study, the antilipoperoxidative and cytoprotective effects of apigenin, baicalein, kaempferol, luteolin and quercetin against doxorubicin-induced oxidative stress were investigated in isolated rat heart cardiac myocytes, mitochondria and microsomes. After preincubation of cardiomyocytes with the test compounds for 1 h the cardiomyocytes were treated with the toxic agent, doxorubicin (100 micro M for 8 h). Cardiomyocyte protection was assessed by extracellular LDH and cellular ADP and ATP production. Cytoprotection was concentration dependent for baicalein > luteolin congruent with apigenin > quercetin > kaempferol. All test compounds had signi fi cantly better protective effects than dexrazoxan, an agent currently used for adjuvant therapy during anthracycline antibiotic therapy. In microsomes/mitochondria the IC(50) values of lipid peroxidation inhibition for quercetin, baicalein, kaempferol, luteolin, and apigenin were 3.1 +/- 0.2/8.2 +/- 0.6, 3.3 +/- 0.3/9.6 +/- 0.5, 3.9 +/- 0.3/10.1 +/- 0.8, 22.9 +/- 1.7/18.2 +/- 0.7, and 338.8 +/- 23.1/73.1 +/- 6.4 mM, respectively. The antilipoperoxidative activity of apigenin differed from its cytoprotective effects, but correlated with the free radical scavenging of 2,2-diphenyl-1-picrylhydrazyl radical and half peak oxidation potential (E(p/2)). Apigenin was the least effective of the flavonoids studied in all models except the cardiomyocyte model where its cardiomyocyte cytoprotective effect was comparable to other compounds. 相似文献
7.
Jitka Vostlov Adla Galandkov Bohumil Zlek Radka Lichnovsk Kateina íkov Jitka Ulrichov Alena Rajnochov Svobodov 《Journal of applied toxicology : JAT》2019,39(5):773-782
Human skin explant (HSE) seems to be a useful model for dermatological/cosmetic testing. HSE prepared from donor superfluous skin from plastic surgery operations is cheap and easily obtainable compared to reconstructed models. The HSE use, however, may be limited by the degeneration processes during cultivation. The aim was to monitor changes in metabolic activity and selected apoptotic, inflammatory and antioxidant parameters during 7 day cultivation. The significant changes were found in the superoxide dismutase‐2 level from day 5, glutathione S‐reductase level from day 6, metabolic activity and fibulin‐5 level from day 4, cyclooxygenase‐2, interleukin‐6 and interleukin‐10 from day 1 to 2. Other selected markers (lipid peroxidation products and glutathione level, glutathione S‐transferase, catalase, superoxide dismutase and glutathione S‐reductase activity, glutathione peroxidase and glutathione S‐reductase levels) were not modified significantly due to high inter‐individual variability of skin donors. The HSE microstructure as well as cytokeratin‐10 and proliferation marker Ki67 expression was also only minimally affected during cultivation. Collectively, the results demonstrate that HSE represents a good model for short‐term studies focused on the physical and chemical agent toxicity, protective potential of compounds or metabolic biotransformation. However, reduced metabolic activity, increased inflammation and the high inter‐individual variability and sensitivity of donors have to be taken into consideration. 相似文献
8.
Differential expression of homologous recombination DNA repair genes in the early and advanced stages of myelodysplastic syndrome 下载免费PDF全文
9.
To get access to the replication site, small non-enveloped DNA viruses have to cross the cell membrane using a limited number of capsid proteins, which also protect the viral genome in the extracellular environment. Most of DNA viruses have to reach the nucleus to replicate. The capsid proteins involved in transmembrane penetration are exposed or released during endosomal trafficking of the virus. Subsequently, the conserved domains of capsid proteins interact with cellular membranes and ensure their efficient permeabilization. This review summarizes our current knowledge concerning the role of capsid proteins of small non-enveloped DNA viruses in intracellular membrane perturbation in the early stages of infection. 相似文献
10.
Jitka Veldema 《Experimental aging research》2013,39(5):400-409
Objectives: It is the main goal of this study to investigate the relationships between physical abilities, cognitive abilities and the aspects of psychological well-being in people aged 80 or older. In contrast to other studies, we focus on the executive functions and mental rotation while investigating cognitive performance; this is because it is well known in the literature investigating younger participants that these functions relate to some kind of motor or physical activity.Methods: 41 independently living persons over 80 years were enrolled. Physical activities (German Physical Activity Questionnaire 50+), balance (One leg stand), psychological well-being (Resilience, General depressions scale), cognitive abilities (Flanker task, Mental rotation, Number connection test) as well as the influence of gender and education status were analyzed.Results: Higher physical activity correlates with higher resilience. Persons with higher education and men show better values on the depression scale. Better mental rotation ability could be detected in persons with higher education.Discussion: This first experimental study with people only over 80 years demonstrates the importance of education and physical activity for different aspects of psychological well-being. Due to the aim of investigating participants only over 80 years living independently the sample size is small so the study should be further enlarged. 相似文献