全文获取类型
收费全文 | 1171篇 |
免费 | 70篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 42篇 |
妇产科学 | 17篇 |
基础医学 | 142篇 |
口腔科学 | 30篇 |
临床医学 | 111篇 |
内科学 | 277篇 |
皮肤病学 | 16篇 |
神经病学 | 138篇 |
特种医学 | 17篇 |
外科学 | 169篇 |
综合类 | 1篇 |
预防医学 | 75篇 |
眼科学 | 5篇 |
药学 | 77篇 |
中国医学 | 2篇 |
肿瘤学 | 122篇 |
出版年
2023年 | 5篇 |
2022年 | 16篇 |
2021年 | 27篇 |
2020年 | 17篇 |
2019年 | 24篇 |
2018年 | 20篇 |
2017年 | 26篇 |
2016年 | 16篇 |
2015年 | 23篇 |
2014年 | 37篇 |
2013年 | 59篇 |
2012年 | 88篇 |
2011年 | 88篇 |
2010年 | 38篇 |
2009年 | 44篇 |
2008年 | 76篇 |
2007年 | 75篇 |
2006年 | 88篇 |
2005年 | 68篇 |
2004年 | 81篇 |
2003年 | 60篇 |
2002年 | 70篇 |
2001年 | 15篇 |
2000年 | 11篇 |
1999年 | 12篇 |
1998年 | 12篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 15篇 |
1991年 | 12篇 |
1990年 | 11篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1966年 | 1篇 |
1939年 | 1篇 |
1937年 | 2篇 |
排序方式: 共有1250条查询结果,搜索用时 15 毫秒
121.
Xavier Dray Gianfranco Donatelli Devi Mukkai Krishnamurty Elena Dubcenco Ronald J. Wroblewski Lia Assumpcao Samuel A. Giday Jonathan M. Buscaglia Eun J. Shin Priscilla Magno Laurie J. Pipitone Michael R. Marohn Sergey V. Kantsevoy Anthony N. Kalloo 《Digestive diseases and sciences》2010,55(9):2463-2470
Introduction
Lasers 2-µm in wavelength offer efficient tissue cutting with limited thermal damage in biological tissue.Objective
To evaluate the dissection capabilities of a 2-μm continuous-wave laser for NOTES procedures.Methods and Procedures
We conducted 18 acute animal experiments. Group 1 (three animals): transcolonic access to the peritoneal cavity (15-W transcolonic laser puncture, balloon dilation over the laser probe). Group 2 (six animals): transcolonic access with needle-knife puncture and balloon dilation. Group 3 (three animals): transgastric access to the peritoneal cavity (similar technique as group 1) followed by laser-assisted dissection of the kidney. In one animal of group 3, a therapeutic target (hematoma) was created by percutaneous puncture of the kidney. Group 4 (six animals): transgastric access (similar to the technique of group 2).Results
Translumenal access to the peritoneal cavity was achieved in 2–3 min in group 1 (significantly shorter than with the needle-knife-assisted technique, 4–5 min, p = 0.02) and in 7–10 min in group 3 (compared to 6–17 min in group 4, p = 0.88). In group 3, laser dissection of the parietal peritoneum and of perinephric connective tissue allowed access to the retroperitoneum with complete removal of a blood collection in the animal with puncture trauma. Laser dissection demonstrated good maneuverability, clean and rapid cutting, and excellent hemostasis. Peritoneoscopy and necropsy showed no damage of targeted tissue and surrounding organs.Conclusions
The 2-μm continuous-wave laser system showed promising capabilities for highly precise and safe dissection during NOTES procedures. 相似文献122.
Uemi M Ronsein GE Prado FM Motta FD Miyamoto S Medeiros MH Di Mascio P 《Chemical research in toxicology》2011,24(6):887-895
In mammalian membranes, cholesterol is concentrated in lipid rafts. The generation of cholesterol hydroperoxides (ChOOHs) and their decomposition products induces various types of cell damage. The decomposition of some organic hydroperoxides into peroxyl radicals is known to be a potential source of singlet molecular oxygen [O(2) ((1)Δ(g))] in biological systems. We report herein on evidence of the generation of O(2) ((1)Δ(g)) from ChOOH isomers in solution or in liposomes containing ChOOHs, which involves a cyclic mechanism from a linear tetraoxide intermediate originally proposed by Russell. Characteristic light emission at 1270 nm, corresponding to O(2) ((1)Δ(g)) monomolecular decay, was observed for each ChOOH isomer or in liposomes containing ChOOHs. Moreover, the presence of O(2) ((1)Δ(g)) was unequivocally demonstrated using the direct spectral characterization of near-infrared light emission. Using (18)O-labeled cholesterol hydroperoxide (Ch(18)O(18)OH), we observed the formation of (18)O-labeled O(2) ((1)Δ(g)) [(18)O(2) ((1)Δ(g))] by the chemical trapping of (18)O(2) ((1)Δ(g)) with 9,10-diphenylanthracene (DPA) and detected the corresponding (18)O-labeled DPA endoperoxide (DPA(18)O(18)O) and the (18)O-labeled products of the Russell mechanism using high-performance liquid chromatography coupled to tandem mass spectrometry. Photoemission properties and chemical trapping clearly demonstrate that the decomposition of Ch(18)O(18)OH generates (18)O(2) ((1)Δ(g)), which is consistent with the Russell mechanism and points to the involvement of O(2) ((1)Δ(g)) in cholesterol hydroperoxide-mediated cytotoxicity. 相似文献
123.
de David C Rodrigues G Bona S Meurer L González-Gallego J Tuñón MJ Marroni NP 《Toxicologic pathology》2011,39(6):949-957
In hepatic toxicity induced in rats by two injections of thioacetamide (TAA, 350 mg/kg with an interval of 8 hr), the action of quercetin was investigated. After 96 hr, TAA administration resulted in hepatic necrosis, significant increases in serum transaminase activity, and increases in hepatic lipoperoxidation. Thioacetamide-induced hepatotoxicity also showed changes in antioxidant enzymes in the liver of rats, with alterations in p-ERK 1/2 (phosphorylated extracellular-signal related kinase 1/2) as well as an imbalance between proapototic protein Bax and anti-apoptotic protein Bcl-2 expression. With administration of the flavonoid quercetin (50 mg/Kg i.p.) for four consecutive days following TAA, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity were close to normal values in rats. Histological findings suggested that quercetin had a preventive effect on TAA-induced hepatic necrosis. Quercetin treatment caused significant decreases in lipid peroxide levels in the TAA-treated rats, with some changes in antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Quercetin also inhibited the change of the p-ERK1/2 by TAA and significantly prevented the increase in Bax/Bcl-2 ratio, thus preventing apoptosis. Findings indicate that quercetin may have a preventive effect on TAA-induced hepatotoxicity by modulating the oxidative stress parameters and apoptosis pathway. 相似文献
124.
Nânci C.D. De Oliveira Merielen S. Sarmento Emilene A. Nunes Carem M. Porto Darlan P. Rosa Silvia R. Bona Graziella Rodrigues Norma P. Marroni Patrícia Pereira Jaqueline N. Picada Alexandre B.F. Ferraz Flavia V. Thiesen Juliana Da Silva 《Food and chemical toxicology》2012
The aim of the present work was to study the protective effects of rosmarinic acid against ethanol-induced DNA damage in mice. The antigenotoxic capacity of rosmarinic acid (100 mg/kg) was tested using pre-, co- and post-treatment with ethanol (5 g/kg). Peripheral blood (1 and 24 h) and brain cells (24 h) were evaluated using the comet assay and bone marrow was analyzed using the micronucleus assay (24 h). The results were compared to data of TBARS, enzymes with antioxidant activity, and DCFH-DA test. Peripheral blood and brain cells show that mean damage index (DI) and damage frequency (DF) values of ethanol with pre-treatment with rosmarinic acid group were significantly lower than in the ethanol group. In brain cells all different treatments with ethanol and rosmarinic acid showed significant decrease in DI and DF mean values when compared to ethanol group and negative control. No significant differences were observed in micronucleus frequency, activity of antioxidant enzymes and TBARS between groups. The DCFH-DA test show a reduction of 18% of fluorescence intensity when compare with ethanol group. The results show that rosmarinic acid could decrease the levels of DNA damage induced by ethanol, for both tissues and treatment periods. 相似文献
125.
Luciana Ghio Mariano Ferraresso Graziella Zacchello Luisa Murer Fabrizio Ginevri Mirco Belingheri Licia Peruzzi Franco Zanon Francesco Perfumo Luisa Berardinelli Silvia Tirelli Luca Dello Strologo Iris Fontana Umberto Valente Massimo Cardillo Alberto Edefonti 《Clinical transplantation》2009,23(2):264-270
Abstract: This longitudinal study assessed the influence of post-transplant clinical and therapeutic variables in 50 kidney transplant recipients aged 2–19 yr receiving a triple immunosuppressive regimen consisting of cyclosporine microemulsion (CsA), steroids and MMF (300–400 mg/m2 body surface area twice daily), the full pharmacokinetic profile (10 points) of which was investigated on post-transplant days 6, 30, 180 and 360. Total plasma MPA was measured by Enzyme Multiplied Immunoassay Technique. CsA therapeutic drug monitoring (TDM) was performed via C2 blood monitoring, while MPA TDM via C0. MPA Cmax, tmax, AUC0-12 and AUC0-4 pharmacokinetic profile changed significantly during the first post-transplant year. C0 was a poor predictor of the total MPA exposure [as measured by the area under the concentration-time curve AUC)], while a truncated AUC was a good surrogate of the 12-h profile (r = 0.91; p < 0.001) Graft function and cyclosporine therapy influenced MPA pharmacokinetics, as shown by the univariate and multivariate analyses. We conclude that because after transplantation MPA exposure varied over time, a strict TDM is advisable in the pediatric population. 相似文献
126.
Citro V Milan G Tripodi FS Gennari A Sorrentino P Gallotta G Postiglione A Tarantino G 《Journal of gastroenterology》2007,42(1):79-82
Background In patients with cirrhosis, subclinical hepatic encephalopathy, which negatively affects the activity of daily living, is
often unidentified. In a multicenter observational study, we investigated the possibility of detecting minimal neurological
changes consistent with subclinical hepatic encephalopathy by using the Trail Making Test in a cohort of patients with liver
cirrhosis at hospital admission.
Methods Seventy-seven consecutive patients with liver cirrhosis were studied (mean age, 69.5 ± 9.1; 95% confidence interval, 67.5–71.6
years). In all patients, possible encephalopathy was investigated according to the West Haven criteria. All those free of
any sign of encephalopathy (West Haven 0) were also studied by the Trail Making Test forms A and B. The Child-Pugh score was
determined in all patients, and results were compared with the West Haven stage. Exclusion criteria were use of benzodiazepine,
beta adrenergic blockers, alcohol, or antiepileptic drugs, or coexistence of depression, dementia, Parkinson's disease, or
chronic or acute cerebral vasculopathy.
Results Of the 77 patients, 44 (57.1%, 23 men and 21 women) had West Haven score 0, but among these, 26 (59.1%) were diagnosed with
mental impairment likely linked to minimal hepatic encephalopathy. Severity of liver disease correlated with the presence
of likely minimal hepatic encephalopathy, because the prevalence of abnormal Trail Making Test results increased from 22.2%
in Child-Pugh A, to 63.4% and 74.0% in Child-Pugh B and C, respectively.
Conclusions The investigation of patients with cirrhosis by the West Haven test is not sufficient to identify subclinical forms of encephalopathy.
The Trail Making Test (a simple, inexpensive test) in our series evidenced poor psychometric performance in more than half
of the patients who were free of manifest encephalopathy. Subclinical hepatic encephalopathy was present mostly in patients
with HCV-related cirrhosis. Detecting minimal hepatic encephalopathy in patients with cirrhosis may help improve their quality
of life. 相似文献
127.
Alessandro D’Elia Graziella Angelina Melone Christian Brogna Anna Formichella Antonio Santoro Maurizio Salvati 《Neurological sciences》2009,30(2):137-141
With the increasing number of cancer survivors, we can observe a population that will present a higher risk of developing
secondary long-term toxicities related to adjuvant chemo and radiotherapy regimens. Among these, children surviving from acute
lymphoblastic leukemia (ALL) that were treated with prophylactic cranial irradiation represent a group of patients at a high
risk of developing secondary brain tumors. Radiation-induced intracranial tumors have been documented since 1950, and today,
more than one-hundred cases have been described. We report our experience with two young patients who were hospitalized for
low grade gliomas and had a positive anamnesis for ALL and consequent radiotherapy. 相似文献
128.
Giuseppina Martella Paola Bonsi Giuseppe Sciamanna Paola Platania Graziella Madeo Annalisa Tassone Dario Cuomo Antonio Pisani 《Epilepsia》2009,50(4):702-710
Purpose: We analyzed the effects of seletracetam (ucb 44212; SEL), a new antiepileptic drug candidate, in an in vitro model of epileptic activity. The activity of SEL was compared to the effects of levetiracetam (LEV; Keppra), in the same assays. Methods: Combined electrophysiologic and microfluorometric recordings were performed from layer V pyramidal neurons in rat cortical slices to study the effects of SEL on the paroxysmal depolarization shifts (PDSs), and the simultaneous elevations of intracellular Ca2+ concentration [Ca2+]i. Moreover, the involvement of high‐voltage activated Ca2+ currents (HVACCs) was investigated by means of patch‐clamp recordings from acutely dissociated pyramidal neurons. Results: SEL significantly reduced both the duration of PDSs (IC50 = 241.0 ± 21.7 nm ) as well as the number of action potentials per PDS (IC50 = 82.7 ± 9.7 nm ). In addition, SEL largely decreased the [Ca2+]i rise accompanying PDSs (up to 75% of control values, IC50 = 345.0 ± 15.0 nm ). Furthermore, SEL significantly reduced HVACCs in pyramidal neurons. This effect was mimicked by ω‐conotoxin GVIA and, to a lesser extent, by ω‐conotoxin MVIIC, blockers of N‐ and Q‐type HVACC, respectively. The combination of these two toxins occluded the action of SEL, suggesting that N‐type Ca2+ channels, and partly Q‐type subtypes are preferentially targeted. Conclusions: These results demonstrate a powerful inhibitory effect of SEL on epileptiform events in vitro. SEL showed a higher potency than LEV. The effective limitation of [Ca2+]i influx might be relevant for its antiepileptic efficacy and, more broadly, for pathologic processes involving neuronal [Ca2+]i overload. 相似文献
129.
The outcome of patients with thoracic vascular prostheses is usually uneventful. We report two cases of collapse of thoracic vascular prostheses which occurred ten and forty years, respectively, after the implantation. The diagnoses were obtained preoperatively by CT-scan or NMR and angiography. Both patients were successfully treated with prosthetic replacement by an open approach. 相似文献
130.
Koch M Mostert J De Keyser J Tremlett H Filippini G 《Annals of neurology》2008,63(1):125-6; author reply 126-7