全文获取类型
收费全文 | 977篇 |
免费 | 61篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 19篇 |
妇产科学 | 19篇 |
基础医学 | 125篇 |
口腔科学 | 15篇 |
临床医学 | 77篇 |
内科学 | 253篇 |
皮肤病学 | 35篇 |
神经病学 | 57篇 |
特种医学 | 31篇 |
外科学 | 180篇 |
综合类 | 13篇 |
一般理论 | 1篇 |
预防医学 | 51篇 |
眼科学 | 21篇 |
药学 | 70篇 |
中国医学 | 11篇 |
肿瘤学 | 55篇 |
出版年
2024年 | 2篇 |
2023年 | 12篇 |
2022年 | 47篇 |
2021年 | 61篇 |
2020年 | 25篇 |
2019年 | 33篇 |
2018年 | 34篇 |
2017年 | 22篇 |
2016年 | 29篇 |
2015年 | 27篇 |
2014年 | 42篇 |
2013年 | 49篇 |
2012年 | 73篇 |
2011年 | 77篇 |
2010年 | 41篇 |
2009年 | 29篇 |
2008年 | 51篇 |
2007年 | 52篇 |
2006年 | 32篇 |
2005年 | 60篇 |
2004年 | 40篇 |
2003年 | 57篇 |
2002年 | 42篇 |
2001年 | 17篇 |
2000年 | 18篇 |
1999年 | 15篇 |
1998年 | 9篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 5篇 |
1982年 | 1篇 |
1979年 | 4篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 3篇 |
1967年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有1039条查询结果,搜索用时 15 毫秒
991.
Shamil Haroon Peymane Adab Carl Griffin Rachel Jordan 《The British journal of general practice》2013,63(606):e55-e62
Background
Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality. However, much of the disease burden remains undiagnosed.Aim
To compare the yield and cost effectiveness of two COPD case-finding approaches in primary care.Design and setting
Pilot randomised controlled trial in two general practices in the West Midlands, UK.Method
A total of 1634 ever-smokers aged 35–79 years with no history of COPD or asthma were randomised into either a ‘targeted’ or ‘opportunistic’ case-finding arm. Respiratory questionnaires were posted to patients in the ‘targeted’ arm and provided to patients in the ‘opportunistic’ arm at routine GP appointments. Those reporting at least one chronic respiratory symptom were invited for spirometry. COPD was defined as pre-bronchodilator forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC)<0.7 and FEV1<80% of predicted. Primary outcomes were the difference in the proportion of patients diagnosed with COPD and the cost per case detected.Results
Twenty-six per cent (212/815) in the ‘targeted’ and 13.6% (111/819) in the ‘opportunistic’ arm responded to the questionnaire and 78.3% (166/212) and 73.0% (81/111), respectively, reported symptoms; 1.2% (10/815) and 0.7% (6/819) of patients in the ‘targeted’ and ‘opportunistic’ arms were diagnosed with COPD (difference in proportions = 0.5% [95% confidence interval {CI} = –0.5% to 3.08%]). Over a 12-month period, the ‘opportunistic’ case-finding yield could be improved to 1.95% (95% CI = 1.0% to 2.9%). The cost-per case detected was £424.56 in the ‘targeted’ and £242.20 in the ‘opportunistic’ arm.Conclusion
Opportunistic case finding may be more effective and cost effective than targeting patients with a postal questionnaire alone. A larger randomised controlled trial with adequate sample size is required to test this. 相似文献992.
Andrew H. Miller M.D. Ebrahim Haroon M.D. Charles L. Raison M.D. Jennifer C. Felger Ph.D. 《Depression and anxiety》2013,30(4):297-306
Increasing attention has been paid to the role of inflammation in a host of illnesses including neuropsychiatric disorders such as depression and anxiety. Activation of the inflammatory response leads to release of inflammatory cytokines and mobilization of immune cells both of which have been shown to access the brain and alter behavior. The mechanisms of the effects of inflammation on the brain have become an area of intensive study. Data indicate that cytokines and their signaling pathways including p38 mitogen‐activated protein kinase have significant effects on the metabolism of multiple neurotransmitters such as serotonin, dopamine, and glutamate through impact on their synthesis, release, and reuptake. Cytokines also activate the kynurenine pathway, which not only depletes tryptophan, the primary amino acid precursor of serotonin, but also generates neuroactive metabolites that can significantly influence the regulation of dopamine and glutamate. Through their effects on neurotransmitter systems, cytokines impact neurocircuits in the brain including the basal ganglia and anterior cingulate cortex, leading to significant changes in motor activity and motivation as well as anxiety, arousal, and alarm. In the context of environmental challenge from the microbial world, these effects of inflammatory cytokines on the brain represent an orchestrated suite of behavioral and immune responses that subserve evolutionary priorities to shunt metabolic resources away from environmental exploration to fighting infection and wound healing, while also maintaining vigilance against attack, injury, and further pathogen exposure. Chronic activation of this innate behavioral and immune response may lead to depression and anxiety disorders in vulnerable individuals. 相似文献
993.
Feriha N. Peracha Raafia R. Khan Arooj Ahmad Sadia J. Khan Sahar Hussein Haroon Rashid Choudry 《Psychiatry, Psychology and Law》2013,20(3):439-447
This article documents a cross-sectional survey of 135 males between the ages of 12 and 17.5 years, who were exposed to militancy, in Swat, Pakistan. The data were collated from Sabaoon, a rehabilitation facility. The results reveal the mean age of the males to be15.5 years. Fifty-two per cent of the sample was in the middle birth order. Fifty-two per cent came from low socioeconomic status (i.e. <US $ 93/month or $3/day); 30% were school dropouts; in 65% of the cases, supervising authority figures were absent; 37% were from among 5 and/or 6 siblings, and 29.5% were from among 8 and/or 9siblings. The militants had abducted 58.5% of the students while 41.5% had volunteered for militancy. The results highlight that poverty, poor quality of life, large family size, illiteracy, and, lack of supervision can serve as potential demographic risk factors in making children vulnerable to militancy. 相似文献
994.
995.
996.
997.
998.
Non-fullerene small acceptor molecules have gained significant attention for application in organic solar cells owing to their advantages over fullerene based acceptors. Efforts are continuously being made to design novel acceptors with greater efficiencies. Here, optoelectronic properties of four novel acceptor–donor–acceptor (A–D–A) type small molecules (A1, A2, A3 and A4) were studied for their applications in organic solar cells. These molecules contain an indacenodithiophene central core unit joined to different end capped acceptors through a monofluoro substituted benzothiadiazole (FBT) donor acceptor (DA) bridge. The different end capped acceptor groups are; 2-2(2-ethylidene-5,6-difluoro-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (A1), 2-2(2-ethylidene-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (A2), 2-(5-ethylidene-6-oxo-5,6-dihydrocyclopenta-b-thiophene-4-ylidene)malononitrile (A3), and 2-2(2-ethylidene-5,6-dicyano-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (A4). The calculated optoelectronic properties of the designed molecules were compared with a well-known reference compound R, which was recently synthesized and reported as being an excellent A–D–A type acceptor molecule. All designed molecules showed the appropriate frontier molecular orbital diagram for a charge transfer. A4 shows the highest absorption maximum (λmax) of 858.6 nm (in chloroform solvent), which was attributed to the strong electron withdrawing end-capped acceptor group. Among all of the designed molecules, A3 exhibits the highest open circuit voltages (Voc) which was (1.84 V) with PTB7-Th and (1.76 V) with the P3HT donor polymer. Owing to a lower value of λe with respect to λh, the designed molecules demonstrated superior electron mobilities when compared with reference R. Among all of the molecules, A4 shows the highest electron mobility owing to the lower value of λe compared to R.Non-fullerene small acceptor molecules have gained significant attention for application in organic solar cells owing to their advantages over fullerene based acceptors. 相似文献
999.
Yaseen Muhammad Ata Ur Rahman Haroon Ur Rashid Maria Sahibzada Sidra Subhan Zhangfa Tong 《RSC advances》2019,9(18):10371
Sulfur compounds in fuel oils are a major source of atmospheric pollution. This study is focused on the hydrodesulfurization (HDS) of dibenzothiophene (DBT) via the coupled application of 0.5 wt% Pd-loaded Co–Mo/Al2O3 and Ni–Mo/Al2O3 catalysts with ionic liquids (ILs) at ambient temperature (120 °C) and pressure (1 MPa H2). The enhanced HDS activity of the solid catalysts coupled with [BMIM]BF4, [(CH3)4N]Cl, [EMIM]AlCl4, and [(n-C8H17)(C4H9)3P]Br was credited to the synergism between hydrogenation by the former and extractive desulfurization and better H2 transport by the latter, which was confirmed by DFT simulation. The Pd-loaded catalysts ranked highest by activity i.e. Pd–Ni–Mo/Al2O3 > Pd–Co–Mo/Al2O3 > Ni–Mo/Al2O3 > Co–Mo/Al2O3. With mild experimental conditions of 1 MPa H2 pressure and 120 °C temperature and an oil : IL ratio of 10 : 3.3, DBT conversion was enhanced from 21% (by blank Ni–Mo/Al2O3) to 70% by Pd–Ni–Mo/Al2O3 coupled with [(n-C8H17)(C4H9)3P]Br. The interaction of polarizable delocalized bonds (in DBT) and van der Waals forces influenced the higher solubility in ILs and hence led to higher DBT conversion. The IL was recycled four times with minimal loss of activity. Fresh and spent catalysts were characterized by FESEM, ICP-MS, EDX, XRD, XPS and BET surface area techniques. GC-MS analysis revealed biphenyl as the major HDS product. This study presents a considerable advance to the classical HDS processes in terms of mild operating conditions, cost-effectiveness, and simplified mechanization, and hence can be envisaged as an alternative approach for fuel oil processing.Synergistic application of ionic liquids with Pd loaded Co–Mo@Al2O3 and Ni–Mo@Al2O3 catalysts for efficient hydrodesulfurization of dibenzothiophene at ambient conditions. 相似文献
1000.
Kannan R.R. Rengasamy Haroon Khan Imad Ahmad Devina Lobine Fawzi Mahomoodally Shanoo Suroowan Sherif T.S. Hassan Suowen Xu Seema Patel Maria Daglia Seyed Mohammad Nabavi Shunmugiah Karutha Pandian 《Medicinal research reviews》2019,39(6):2153-2171
Antiplatelet drugs reduce the risks associated with atherothrombotic events and show various applications in diverse cardiovascular diseases including myocardial infarctions. Efficacy of the current antiplatelet medicines including aspirin, clopidogrel, prasugrel and ticagrelor, and the glycoprotein IIb/IIIa antagonists, are limited due to their increased risks of bleeding, and antiplatelet drug resistance. Hence, it is important to develop new effective antiplatelet drugs, with fewer side-effects. The vast repertoire of natural peptides can be explored towards this goal. Proteins and peptides derived from snake venoms and plants represent exciting candidates for the development of novel and potent antiplatelet agents. Consequently, this review discusses multiple peptides that have displayed antiplatelet aggregation activity in preclinical drug development stages. This review also describes the antiplatelet mechanisms of the peptides, emphasizing the signaling pathways intervened by them. Also, the hurdles encountered during the development of peptides into antiplatelet drugs have been listed. Finally, hitherto unexplored peptides with the potential to prevent platelet aggregation are explored. 相似文献