全文获取类型
收费全文 | 899篇 |
免费 | 57篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 26篇 |
妇产科学 | 20篇 |
基础医学 | 74篇 |
口腔科学 | 25篇 |
临床医学 | 112篇 |
内科学 | 201篇 |
皮肤病学 | 9篇 |
神经病学 | 45篇 |
特种医学 | 40篇 |
外科学 | 175篇 |
综合类 | 22篇 |
预防医学 | 41篇 |
眼科学 | 34篇 |
药学 | 48篇 |
中国医学 | 2篇 |
肿瘤学 | 67篇 |
出版年
2024年 | 2篇 |
2023年 | 13篇 |
2022年 | 51篇 |
2021年 | 62篇 |
2020年 | 40篇 |
2019年 | 32篇 |
2018年 | 53篇 |
2017年 | 28篇 |
2016年 | 30篇 |
2015年 | 33篇 |
2014年 | 49篇 |
2013年 | 53篇 |
2012年 | 84篇 |
2011年 | 81篇 |
2010年 | 48篇 |
2009年 | 27篇 |
2008年 | 36篇 |
2007年 | 27篇 |
2006年 | 30篇 |
2005年 | 26篇 |
2004年 | 19篇 |
2003年 | 29篇 |
2002年 | 20篇 |
2001年 | 6篇 |
2000年 | 13篇 |
1999年 | 4篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 4篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有966条查询结果,搜索用时 0 毫秒
51.
Anissa Chouikha Wasfi Fares Asma Laamari Sondes Haddad-Boubaker Zeineb Belaiba Kais Ghedira Wafa Kammoun Rebai Kaouther Ayouni Marwa Khedhiri Samar Ben Halima Henda Krichen Henda Touzi Imen Ben Dhifallah Fatma Z. Guerfali Chiraz Atri Saifeddine Azouz Oussema Khamessi Monia Ardhaoui Mouna Safer Nissaf Ben Alaya Ikram Guizani Rym Kefi Mariem Gdoura Henda Triki 《Viruses》2022,14(3)
Documenting the circulation dynamics of SARS-CoV-2 variants in different regions of the world is crucial for monitoring virus transmission worldwide and contributing to global efforts towards combating the pandemic. Tunisia has experienced several waves of COVID-19 with a significant number of infections and deaths. The present study provides genetic information on the different lineages of SARS-CoV-2 that circulated in Tunisia over 17 months. Lineages were assigned for 1359 samples using whole-genome sequencing, partial S gene sequencing and variant-specific real-time RT-PCR tests. Forty-eight different lineages of SARS-CoV-2 were identified, including variants of concern (VOCs), variants of interest (VOIs) and variants under monitoring (VUMs), particularly Alpha, Beta, Delta, A.27, Zeta and Eta. The first wave, limited to imported and import-related cases, was characterized by a small number of positive samples and lineages. During the second wave, a large number of lineages were detected; the third wave was marked by the predominance of the Alpha VOC, and the fourth wave was characterized by the predominance of the Delta VOC. This study adds new genomic data to the global context of COVID-19, particularly from the North African region, and highlights the importance of the timely molecular characterization of circulating strains. 相似文献
52.
Dmitry Olegovich Bokov Mustafa Z. Mahmoud Gunawan Widjaja Wanich Suksatan Supat Chupradit Usama S. Altimari Hussein Ali Hussein Yasser Fakri Mustafa Milad kazemnejadi 《RSC advances》2022,12(18):10933
A reductive filter paper for selective nitro reduction has been prepared by modification of a pristine cellulose filter paper by Pd/C nanoparticles, as a portable catalyst. The reaction was performed in two different set-ups including (i) filtration and (ii) sealed systems, in the presence of ammonium formate and ex situ generated hydrogen gas reducing agents, respectively. In the sealed system in the presence of H2 gas, the halogenated nitroarenes were completely reduced, while in the filtration system, different derivatives of the nitroarenes were selectively reduced to aryl amines. In both systems, the reduction of nitroarenes to aryl amines was performed with high efficiency and selectivity, comparable to a heterogeneous system. Reaction parameters were comprehensively designed using Design Expert software and then studied. The properties of the catalytic filter paper were studied in detail from the points of view of swellability, shrinkage, reusability, and stability against acidic, alkaline, and oxidative reagents.A novel and efficient catalytic filtration has been developed for the selective reduction of nitro compounds on a Pd/C-doped cellulose filter paper. 相似文献
53.
54.
Raha Orfali Mahmoud A. Aboseada Nada M. Abdel-Wahab Hossam M. Hassan Shagufta Perveen Fuad Ameen Eman Alturki Usama Ramadan Abdelmohsen 《RSC advances》2021,11(28):17116
The genus Aspergillus is widely distributed in terrestrial and marine environments. In the marine environment, several Aspergillus species have proved their potential to produce a plethora of secondary metabolites including polyketides, sterols, fatty acids, peptides, alkaloids, terpenoids and miscellaneous compounds, displaying a variety of pharmacological activities such as antimicrobial, cytotoxicity, anti-inflammatory and antioxidant activity. From the beginning of 2015 until December 2020, about 361 secondary metabolites were identified from different marine Aspergillus species. In our review, we highlight secondary metabolites from various marine-derived Aspergillus species reported between January 2015 and December 2020 along with their biological potential and structural aspects whenever applicable.The genus Aspergillus is widely distributed in terrestrial and marine environments. 相似文献
55.
Eman Maher Zahran Ahmed M. Sayed Miada F. Abdelwahab Amgad Albohy Basma S. Abdulrazik Ayman M. Ibrahim Gerhard Bringmann Usama Ramadan Abdelmohsen 《RSC advances》2021,11(57):36042
Cerebrosides are a group of metabolites belonging to the glycosphingolipids class of natural products. So far, 167 cerebrosides, compounds 1–167, have been isolated from diverse marine organisms or microorganisms. The as yet smaller number of compounds that have been studied more in depth proves a potential against challenging diseases, such as cancer, a range of viral and bacterial diseases, as well as inflammation. This review provides a comprehensive summary on this so far under-explored class of compounds, their chemical structures, bioactivities, and their marine sources, with a full coverage to the end of 2020. Today, the global pandemic concern, COVID-19, has claimed millions of death cases around the world, making the development of anti-SARS-CoV-2 drugs urgently needed for such a battle. Accordingly, selected examples from all subclasses of cerebrosides were virtually screened for potential inhibition of SARS-CoV-2 proteins that are crucially involved in the viral–host interaction, viral replication, or in disease progression. The results highlight five cerebrosides that could preferentially bind to the hACE2 protein, with binding scores between −7.1 and −7.6 kcal mol−1 and with the docking poses determined underneath the first α1-helix of the protein. Moreover, the molecular interaction determined by molecular dynamic (MD) simulation revealed that renieroside C1 (60) is more conveniently involved in key hydrophobic interactions with the best stability, least deviation, least ΔG (−6.9 kcal mol−1) and an RMSD value of 3.6 Å. Thus, the structural insights assure better binding affinity and favorable molecular interaction of renieroside C1 (60) towards the hACE2 protein, which plays a crucial role in the biology and pathogenesis of SARS-CoV-2.Cerebrosides are a group of metabolites belonging to the glycosphingolipids class of natural products. 相似文献
56.
Omnia Hesham Abdelhafez John Refaat Fahim Ramy R. El Masri M. Alaraby Salem Samar Yehia Desoukey Safwat Ahmed Mohamed Salah Kamel Sheila Marie Pimentel-Elardo Justin R. Nodwell Usama Ramadan Abdelmohsen 《RSC advances》2021,11(38):23654
Soft corals belonging to the family Nephtheidae have been appreciated as marine sources of diverse metabolites with promising anticancer potential. In view of that, the current work investigates the anti-proliferative potential of the crude extract, different fractions, and green synthesized silver nanoparticles (AgNPs) of the Red Sea soft coral, Nephthea sp. against a panel of tumor cell lines. The metabolic pool of the soft coral under study was also explored via an LC-HR-ESI-MS metabolomics approach, followed by molecular docking analysis of the characterized metabolites against the target proteins, EGFR, VEGFR, and HER2 (erbB2) that are known to be involved in cancer cell proliferation, growth, and survival. Overall, the n-butanol fraction of Nephthea sp. exhibited the highest inhibitory activities against MCF7 (breast cancer) and A549 (lung cancer) cell lines, with interesting IC50 values of 2.30 ± 0.07 and 3.12 ± 0.10 μg ml−1, respectively, whereas the maximum growth inhibition of HL60 (leukemia) cells was recorded by the total extract (IC50 = 2.78 ± 0.09 μg ml−1). More interestingly, the anti-proliferative potential of the total soft coral extract was evidently improved when packaged in the form of biogenic AgNPs, particularly against A549 and MCF7 tumor cells, showing IC50 values of 0.72 ± 0.06 and 9.32 ± 0.57 μg ml−1, respectively. On the other hand, metabolic profiling of Nephthea sp. resulted in the annotation of structurally diverse terpenoids, some of which displayed considerable binding affinities and molecular interactions with the studied target proteins, suggesting their possible contribution to the anti-proliferative properties of Nephthea sp. via inhibition of tyrosine kinases, especially the EGFR type. Taken together, the present findings highlighted the relevance of Nephthea sp. to future anticancer drug discovery and provided a base for further work on the green synthesis of a range of bioactive NPs from marine soft corals.The cytotoxic potential of the crude extract, different fractions, and green synthesized nanoparticles of the soft coral Nephthea sp. was studied, supported by LC-HR-ESI-MS metabolomics analysis and molecular docking of the dereplicated compounds. 相似文献
57.
58.
59.
Doreen A. Ezeife MD Francois Dionne PhD Aline Fusco Fares MD Ellen Laura Rose Cusano MD Rouhi Fazelzad BSc MISt Wenzie Ng BSc MPharm RPh Don Husereau BSc Pharm MSc Farzad Ali BPharm MSc Christina Sit MSc Barry Stein B.Com BCL LLB Jennifer H. Law MSc Lisa Le MSc Peter Michael Ellis MD MMed PhD Scott Berry MD Stuart Peacock PhD Craig Mitton PhD Craig C. Earle MD Kelvin K. W. Chan MD PhD Natasha B. Leighl MD MMSc 《Cancer》2020,126(7):1530-1540
60.
Omar Hassanen Usama Ghieda Mohamed A. Eltomey 《The Egyptian Journal of Radiology and Nuclear Medicine》2017,48(4):1117-1123