全文获取类型
收费全文 | 819篇 |
免费 | 24篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 18篇 |
妇产科学 | 27篇 |
基础医学 | 138篇 |
口腔科学 | 4篇 |
临床医学 | 38篇 |
内科学 | 205篇 |
皮肤病学 | 12篇 |
神经病学 | 72篇 |
特种医学 | 9篇 |
外科学 | 107篇 |
综合类 | 4篇 |
预防医学 | 44篇 |
眼科学 | 3篇 |
药学 | 87篇 |
中国医学 | 1篇 |
肿瘤学 | 75篇 |
出版年
2022年 | 20篇 |
2021年 | 23篇 |
2020年 | 17篇 |
2019年 | 9篇 |
2018年 | 14篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2015年 | 16篇 |
2014年 | 18篇 |
2013年 | 30篇 |
2012年 | 32篇 |
2011年 | 45篇 |
2010年 | 21篇 |
2009年 | 28篇 |
2008年 | 31篇 |
2007年 | 61篇 |
2006年 | 49篇 |
2005年 | 65篇 |
2004年 | 58篇 |
2003年 | 39篇 |
2002年 | 51篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 10篇 |
1998年 | 9篇 |
1997年 | 22篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 3篇 |
1992年 | 10篇 |
1991年 | 9篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 12篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1976年 | 4篇 |
1974年 | 5篇 |
1973年 | 3篇 |
1967年 | 5篇 |
1965年 | 2篇 |
1958年 | 2篇 |
1928年 | 2篇 |
排序方式: 共有855条查询结果,搜索用时 78 毫秒
161.
Vincent Gregoire Marc HamoirChanghu Chen Madeleine KaneAndrzej Kawecki Pramod K. JulkaHung-Ming Wang Srihari PrasadAnil K. D’Cruz Ljiljana Radosevic-JelicRejnish R. Kumar Stanislaw KorzeniowskiJacek Fijuth Jean-Pascal MachielsMark V. Sellers Ilian TchakovDavid Raben 《Radiotherapy and oncology》2011,100(1):62-69
Background and purpose
To assess the efficacy and safety of gefitinib given concomitantly and/or as maintenance therapy to standard cisplatin/radiotherapy for previously untreated, unresected, stage III/IV non-metastatic SCCHN.Materials and methods
In this phase II, double-blind, study, 226 patients were randomized to gefitinib 250 mg/day, 500 mg/day or placebo in two phases: a concomitant phase (gefitinib or placebo with chemoradiotherapy), followed by a maintenance phase (gefitinib or placebo alone). Primary endpoint was local disease control rate (LDCR) at 2 years; secondary endpoints were LDCR at 1 year, objective response rate, progression-free survival, overall survival, and safety and tolerability.Results
Gefitinib (250 and 500 mg/day) did not improve 2-year LDCR compared with placebo either when given concomitantly with chemoradiotherapy (32.7% vs. 33.6%, respectively; OR 0.921, 95% CI 0.508, 1.670 [1-sided p = 0.607]) or as maintenance therapy (28.8% vs. 37.4%, respectively; OR 0.684, 95% CI 0.377, 1.241 [1-sided p = 0.894]). Secondary efficacy outcomes were broadly consistent with the 2-year LDCR results. In both doses, gefitinib was well-tolerated and did not adversely affect the safety and tolerability of concomitant chemoradiotherapy.Conclusion
Gefitinib was well-tolerated, but did not improve efficacy compared with placebo when given concomitantly with chemoradiotherapy, or as maintenance therapy alone. 相似文献162.
This paper presents the application of genetic algorithm for the integration of neural classifiers combined in the ensemble for the accurate recognition of heartbeat types on the basis of ECG registration. The idea presented in this paper is that using many classifiers arranged in the form of ensemble leads to the increased accuracy of the recognition. In such ensemble the important problem is the integration of all classifiers into one effective classification system. This paper proposes the use of genetic algorithm. It was shown that application of the genetic algorithm is very efficient and allows to reduce significantly the total error of heartbeat recognition. This was confirmed by the numerical experiments performed on the MIT BIH Arrhythmia Database. 相似文献
163.
Howatson G Taylor MB Rider P Motawar BR McNally MP Solnik S DeVita P Hortobágyi T 《The European journal of neuroscience》2011,33(5):978-990
Unilateral lengthening contractions provide a greater stimulus for neuromuscular adaptation than shortening contractions in the active and non-active contralateral homologous muscle, although little is known of the potential mechanism. Here we examined the possibility that corticospinal and spinal excitability vary in a contraction-specific manner in the relaxed right flexor carpi radialis (FCR) when humans perform unilateral lengthening and shortening contractions of the left wrist flexors at the same absolute force. Corticospinal excitability in the relaxed right FCR increased more during lengthening than shortening at 80% and 100% of maximum voluntary contraction (MVC). Short-interval intracortical inhibition diminished during shortening contractions, and it became nearly abolished during lengthening. Intracortical facilitation lessened during shortening but increased during lengthening. Interhemispheric inhibition to the 'non-active' motor cortex diminished during shortening, and became nearly abolished during lengthening at 90% MVC. The amplitude of the Hoffman reflex in the relaxed right FCR decreased during and remained depressed for 20 s after lengthening and shortening of the left wrist flexors. We discuss the possibility that instead of the increased afferent input, differences in the descending motor command and activation of brain areas that link function of the motor cortices during muscle lengthening vs. shortening may cause the contraction-specific modulation of ipsilateral motor cortical output. In conclusion, ipsilateral motor cortex responses to transcranial magnetic stimulation are contraction-specific; unilateral lengthening and shortening contractions reduced contralateral spinal excitability, but uniquely modulated ipsilateral corticospinal excitability and the networks involved in intracortical and interhemispheric connections, which may have clinical implications. 相似文献
164.
Luszczki JJ Andres-Mach M Barcicka-Klosowska B Florek-Luszczki M Haratym-Maj A Czuczwar SJ 《Progress in neuro-psychopharmacology & biological psychiatry》2011,35(8):1870-1876
The aim of this study was to determine the effect of WIN 55,212-2 mesylate (WIN — a non-selective cannabinoid CB1 and CB2 receptor agonist) on the protective action of four classical antiepileptic drugs (AEDs: clonazepam [CZP], ethosuximide [ETS], phenobarbital [PB], and valproate [VPA]) in the mouse pentylenetetrazole (PTZ)-induced clonic seizure model.WIN (15 mg/kg, i.p.) significantly enhanced the anticonvulsant action of ETS, PB and VPA, but not that of CZP against PTZ-induced clonic seizures. The ED50 values of ETS, PB and VPA were reduced from 148.0, 13.9 and 137.1 mg/kg to 104.0, 8.3 and 85.6 mg/kg, respectively (P < 0.05). WIN (5 and 10 mg/kg, i.p.) had no impact on the anticonvulsant action of all studied AEDs against PTZ-induced clonic seizures. WIN (15 mg/kg, i.p.) significantly elevated total brain concentrations of ETS and VPA, but not those of CZP and PB in mice. Moreover, WIN combined with CZP, ETS, PB and VPA significantly impaired motor performance, long-term memory and muscular strength in mice subjected to the chimney, passive avoidance and grip-strength tests, respectively.Pharmacodynamic enhancement of the anticonvulsant action of PB by WIN against PTZ-induced clonic seizures is favorable from a preclinical viewpoint. Advantageous effects of WIN in combination with ETS and VPA against PTZ-induced seizures were pharmacokinetic in nature. However, WIN combined with CZP, ETS, PB and VPA impaired motor coordination and long-term memory as well as reduced skeletal muscular strength in the experimental animals. 相似文献
165.
Sawosz P Kacprzak M Zolek N Weigl W Wojtkiewicz S Maniewski R Liebert A 《Journal of biomedical optics》2010,15(6):066025
An imaging system for brain oxygenation based on a time-gated, intensified charge-coupled device camera was developed. It allows one to image diffusely reflected light from an investigated medium at defined time windows delayed with respect to the laser pulse. Applying a fast optomechanical switch to deliver the light at a wavelength of 780 nm to nine source fibers allowed one to acquire images in times as short as 4 s. Thus, the system can be applied in in vivo studies. The system was validated in phantom experiments, in which absorbing inclusions were localized at different depths and different lateral positions. Then, the decrease in absorption of the brain tissue related to increase in oxygenation was visualized in the motor cortex area during finger tapping by a healthy volunteer. 相似文献
166.
Overexpression of heme oxygenase-1 in murine melanoma: increased proliferation and viability of tumor cells, decreased survival of mice 总被引:3,自引:0,他引:3 下载免费PDF全文
Was H Cichon T Smolarczyk R Rudnicka D Stopa M Chevalier C Leger JJ Lackowska B Grochot A Bojkowska K Ratajska A Kieda C Szala S Dulak J Jozkowicz A 《The American journal of pathology》2006,169(6):2181-2198
Heme oxygenase-1 (HO-1), a cytoprotective enzyme, can be induced in tumors in response to anti-cancer therapies. We investigated the role of HO-1 in B16(F10), S91, and Sk-mel188 melanoma cells. Overexpression of HO-1 after transduction with adenoviral vectors increased cell proliferation, resistance to oxidative stress generated by H2O2, and angiogenic potential as determined by induction of endothelial cell divisions. Likewise, cells stably transfected with HO-1 cDNA (B16-HO-1) showed higher proliferation, stress resistance, and angiogenic activity than the wild-type line (B16-WT). HO-1 overexpression in tumors significantly shortened survival of mice after subcutaneous injection of cancer cells (38 and 22 days for B16-WT and B16-HO-1, respectively; P=0.017). This also resulted in development of more packed tumors, with more melanoma cells, and reduced inflammatory edemas. Mice injected with B16-HO-1 had lower levels of tumor necrosis factor and higher serum concentrations of its soluble receptor tumor necrosis factor-RI, whereas tumors overexpressing HO-1 displayed augmented vascularization and stronger production of vascular endothelial growth factor. Finally, B16-HO-1 cells injected intravenously formed more metastases in lungs. Thus, HO-1 overexpression increased viability, proliferation, and angiogenic potential of melanoma cells, augmented metastasis, and decreased survival of tumor-bearing mice, suggesting that induction of HO-1 may be detrimental in anti-cancer therapy of melanoma. 相似文献
167.
168.
169.
170.
KL Brierley E Blouch W Cogswell JP Homer D Pencarinha CL Stanislaw ET Matloff 《Cancer journal (Sudbury, Mass.)》2012,18(4):303-309
ABSTRACT: Cancer genetic counseling and testing are now integral services in progressive cancer care. There has been much debate over whether these services should be delivered by providers with specialized training in genetics or by all clinicians. Adverse outcomes resulting from cancer genetic counseling and testing performed by clinicians without specialization in genetics have been reported, but formal documentation is sparse. In this review, we present a series of national cases illustrating major patterns of errors in cancer genetic counseling and testing and the resulting impact on medical liability, health care costs, and the patients and their families. 相似文献