全文获取类型
收费全文 | 4054篇 |
免费 | 283篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 74篇 |
妇产科学 | 77篇 |
基础医学 | 559篇 |
口腔科学 | 67篇 |
临床医学 | 378篇 |
内科学 | 935篇 |
皮肤病学 | 81篇 |
神经病学 | 271篇 |
特种医学 | 130篇 |
外科学 | 552篇 |
综合类 | 73篇 |
一般理论 | 2篇 |
预防医学 | 327篇 |
眼科学 | 238篇 |
药学 | 295篇 |
中国医学 | 29篇 |
肿瘤学 | 244篇 |
出版年
2024年 | 10篇 |
2023年 | 55篇 |
2022年 | 133篇 |
2021年 | 208篇 |
2020年 | 152篇 |
2019年 | 190篇 |
2018年 | 229篇 |
2017年 | 151篇 |
2016年 | 173篇 |
2015年 | 160篇 |
2014年 | 189篇 |
2013年 | 259篇 |
2012年 | 371篇 |
2011年 | 361篇 |
2010年 | 223篇 |
2009年 | 179篇 |
2008年 | 255篇 |
2007年 | 245篇 |
2006年 | 193篇 |
2005年 | 132篇 |
2004年 | 123篇 |
2003年 | 108篇 |
2002年 | 67篇 |
2001年 | 16篇 |
2000年 | 18篇 |
1999年 | 15篇 |
1998年 | 14篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有4374条查询结果,搜索用时 0 毫秒
1.
Abbas Pardakhty Alireza Foroumadi Mehdi Hashemi Saeed Rajabalian Mahmoud Reza Heidari 《Toxicology in vitro》2007,21(6):1031-1038
We examined the cytotoxic potential of nine N-[2-substituted-2-(2-thienyl)ethyl] piperazinyl quinolone derivatives on human oral epithelial mouth carcinoma (KB) and human squamous carcinoma (A431) cell lines. Phototoxic properties of these compounds were also evaluated by mouse 3T3 fibroblast under ultraviolet-A (UVA) irradiation. The percent of cell viability was evaluated by MTT assay. Compound 6 having a 4-[2-(phenylmethoxyimino)-2-(2-thienyl)ethyl] group attached to N4 position of piperazine ring of enoxacin showed the highest cytotoxicity potential on both A431 and KB cell lines (IC50 of 3.11+/-0.52 and 4.91+/-1.94 microg/ml, respectively). While some of the other tested compounds exhibited clear phototoxic potential in 3T3 cell line, compound 6 showed only a minor potential of phototoxicity. These findings suggest the high potential of 4-[2-(phenylmethoxyimino)-2-(2-thienyl)ethyl] derivative of enoxacin as a cytotoxic compound with low potency of phototoxic reactions. The mentioned chemical was identified to be of special interest for further characterization. 相似文献
2.
3.
H Mehdi N K Garg 《Transactions of the Royal Society of Tropical Medicine and Hygiene》1987,81(4):633-636
The contents of total lipids, total sterols, total and individual phospholipids: lysophosphatidyl choline, lysophosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl ethanolamine and alkali-stable phospholipids I and II, were significantly lower in mature cysts of Acanthamoeba culbertsoni strain A-1 than in trophozoites. The major constituent sterols of trophozoites, viz. ergosterol, 7-dehydrostigmasterol and 7,22,25-tridehydrostigmasterol which resolved as a single spot on thin-layer chromatography, disappeared in the cysts. When trophozoites grown in the presence of [14C]acetate were transferred to encystation medium, there was a steady decrease in the radioactivity in the lipids and acid-soluble fraction (glycogen) of the encysting cells while the radioactivity increased in the akali-insoluble fraction (cellulose). The activity of isocitrate lyase in the encysting cells steadily increased up to 24 h of encystation, followed by a slight decrease during 24-32 h, but the activity of isocitrate dehydrogenase steadily decreased up to 32 h of encystation, beyond which time no enzyme activity was detected. Inhibitors of isocitrate lyase, glycolate and maleate at 8.5 to 34 mM concentration inhibited encystation by 18-67%. 相似文献
4.
Christopher D Herzog Biplob Dass James E Holden James Stansell Mehdi Gasmi Mark H Tuszynski Raymond T Bartus Jeffrey H Kordower 《Movement disorders》2007,22(8):1124-1132
Neurturin (NTN) is a potent survival factor for midbrain dopaminergic neurons. CERE-120, an adeno-associated virus type 2 (AAV2) vector encoding human NTN (AAV2-NTN), is currently being developed as a potential therapy for Parkinson's disease. This study examined the bioactivity and safety/tolerability of AAV2-NTN in the aged monkey model of nigrostriatal dopamine insufficiency. Aged rhesus monkeys received unilateral injections of AAV2-NTN into the caudate and putamen, with each animal therefore serving as its own control. Robust expression of NTN within the nigrostriatal system was observed 8 months postadministration. (18)F-fluorodopa imaging using positron emission tomography revealed statistically significant increases in (18)F-fluorodopa uptake in the injected striatum compared with the uninjected side at 4 and 8 months. In addition, at 8 months postadministration, a significant enhancement in tyrosine hydroxylase immunoreactive fibers and an increase in the number of tyrosine hydroxylase immunoreactive cells was observed in the AAV2-NTN injected striatum compared with the uninjected side. Robust activation of phosphorylated extracellular signal-regulated kinase immunoreactivity in the substantia nigra was also observed. Histopathological analyses revealed no adverse effects of AAV2-NTN in the brain. Collectively, these results are consistent with the neurotrophic effects of NTN on the dopaminergic nigrostriatal system and extend the growing body of evidence supporting the concept that AAV2-NTN may have therapeutic benefit for Parkinson's disease. 相似文献
5.
6.
Antibody- and complement-mediated lysis of HIV-infected cells and inhibition of viral replication 总被引:4,自引:0,他引:4
HIV-1-positive antisera were tested for their ability to lyse HIV-1-infected cells in the presence of active complement. Cytolytic effects caused by sera derived from infected humans were slower than those observed with sera from immunised chimpanzees. Lytic but also negative sera were found among HIV-1-infected asymptomatic men as well as among clinical AIDS cases. Human antisera that lysed infected cells reacted similarly irrespective of whether the complement was heterologous or autologous. Analysis of complement-mediated lysis using defined antisera against recombinant HIV-1 env or core antigens suggested that gp160/gp120 and p24 can act as target antigens for an antibody- and complement-mediated cytolysis of infected cells. Complement alone reduced the spread of HIV-1 infection in CD4+ cells and the ability of HIV-1 and HIV-2 to form plaques in CD4-transfected HeLa cells. Co-operative effects of specific antibodies and complement were the most effective in inhibiting HIV infections. 相似文献
7.
A 58-year-old male presented with fatigue, tiredness, and pruritus after hot showers and an elevated white blood cell count (20000/mm(3)). A diagnosis of polycythemia vera (PV) was made after investigation revealed a low erythropoietin and elevated leukocyte alkaline phosphatase (LAP) score; he was treated with repeated phlebotomies. Two years later he developed elevated white counts again and investigation revealed Philadelphia chromosome positive (19/20 cells) chronic myelocytic leukemia (CML). The karyotype also revealed trisomy 9 in 1 of 20 cells. He was treated with imatinib mesylate and went into clinical, hematologic, cytogenetic, and molecular remission. Repeat chromosomal analysis revealed absence of Philadelphia chromosome and BCR/ABL translocation but presence of trisomy 9. To our knowledge, this is the first reported case of coexisting PV and CML both associated with separate chromosomal abnormalities. This also raises an interesting therapeutic consideration of using concomitant imatinib mesylate and hydroxyurea. 相似文献
8.
Kim Han Komudi Singh Matthew J. Rodman Shahin Hassanzadeh Yvonne Baumer Rebecca D. Huffstutler Jinguo Chen Julin Candia Foo Cheung Katherine E. R. Stagliano Mehdi Pirooznia Tiffany M. Powell-Wiley Michael N. Sack 《Nutrients》2021,13(5)
Intermittent fasting and fasting mimetic diets ameliorate inflammation. Similarly, serum extracted from fasted healthy and asthmatic subjects’ blunt inflammation in vitro, implicating serum components in this immunomodulation. To identify the proteins orchestrating these effects, SOMAScan technology was employed to evaluate serum protein levels in healthy subjects following an overnight, 24-h fast and 3 h after refeeding. Partial least square discriminant analysis identified several serum proteins as potential candidates to confer feeding status immunomodulation. The characterization of recombinant IGFBP1 (elevated following 24 h of fasting) and PYY (elevated following refeeding) in primary human CD4+ T cells found that they blunted and induced immune activation, respectively. Furthermore, integrated univariate serum protein analysis compared to RNA-seq analysis from peripheral blood mononuclear cells identified the induction of IL1RL1 and MFGE8 levels in refeeding compared to the 24-h fasting in the same study. Subsequent quantitation of these candidate proteins in lean versus obese individuals identified an inverse regulation of serum levels in the fasted subjects compared to the obese subjects. In parallel, IL1RL1 and MFGE8 supplementation promoted increased CD4+ T responsiveness to T cell receptor activation. Together, these data show that caloric load-linked conditions evoke serological protein changes, which in turn confer biological effects on circulating CD4+ T cell immune responsiveness. 相似文献
9.
Damodaran Shivashankar Bullock Brenna Ekwenna Obi Nayebpour Mehdi Koizumi Naoru Sindhwani Puneet Ortiz Jorge 《International urology and nephrology》2021,53(3):439-446
International Urology and Nephrology - Delayed graft function (DGF) is a manifestation of acute kidney injury uniquely framed within the transplant process and a predictor of poor long-term graft... 相似文献
10.
Endometrial receptivity and implantation are important topics in reproductive sciences. No evidence was found to support sperm involvement in endometrial receptivity and its associated factors. This study aimed to explore the effect of the normal human spermatozoa–endometrium cell interaction in regulating genes in the endometrial receptivity pathway. Semen samples were collected from a healthy and fertile man; then, they were incubated with endometrial cells for 24 hr and considered as the sperm group. A group was cultured without spermatozoa and considered as a control group. About 24 hr later, cells were collected from the bottom of the culture dish. The expressions of the VEGF, FGF2, HBEGF, LIFR, EGF, LIF, MUC1, HOXA10, CSF and PGR genes were evaluated in the two groups. Statistical analysis was performed using an independent sample test. Compared with the control group, in the sperm group, the mRNA levels of PGR (p = .0451), VEGF (p = .0101), HBEGF (p = .0163), EFG (p = .0339), FGF2 (p = .012), LIF (p = .0324), LIFR (p = .0321) and HOXA10 (p = .0098) were significantly upregulated. The results showed that there is a need for the interaction between spermatozoa and endometrium for implantation and can be used for preparing uterine in in vitro fertilisation cycles. 相似文献