全文获取类型
收费全文 | 511篇 |
免费 | 33篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 12篇 |
妇产科学 | 28篇 |
基础医学 | 39篇 |
口腔科学 | 10篇 |
临床医学 | 38篇 |
内科学 | 95篇 |
皮肤病学 | 26篇 |
神经病学 | 19篇 |
特种医学 | 14篇 |
外科学 | 133篇 |
综合类 | 9篇 |
一般理论 | 1篇 |
预防医学 | 32篇 |
眼科学 | 10篇 |
药学 | 39篇 |
肿瘤学 | 47篇 |
出版年
2023年 | 9篇 |
2022年 | 10篇 |
2021年 | 23篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 27篇 |
2017年 | 20篇 |
2016年 | 14篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 23篇 |
2012年 | 49篇 |
2011年 | 35篇 |
2010年 | 15篇 |
2009年 | 11篇 |
2008年 | 16篇 |
2007年 | 26篇 |
2006年 | 25篇 |
2005年 | 23篇 |
2004年 | 27篇 |
2003年 | 23篇 |
2002年 | 16篇 |
2001年 | 10篇 |
2000年 | 9篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1981年 | 6篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有571条查询结果,搜索用时 15 毫秒
71.
72.
Cerastes cerastes and Cerastes vipera venoms were anticoagulant at high concentrations and procoagulant at low concentrations. Ëach venom was fractionated by Sephadex G-100 gel filtration into 8 fractions. Arginine esterase activity in C. cerastes venom was found in three overlapping peaks of mol. wts 70,000, 54,000 and 39,000 and in two peaks of mol. wts 62,000 and 37,000 in the corresponding fractions of C. vipera venom. Two fractions were anticoagulant whereas three fractions were procoagulant in both species. The procoagulant fractions coincided with the arginine esterase activity, while the anticoagulant fractions had proteolytic activity. The anticoagulant activity, in both fractions, is due mainly to direct and/or indirect fibrinogenolysis. The procoagulant activity is probably due to activation at multiple sites in the blood coagulation cascade. 相似文献
73.
74.
Salem ML 《International immunopharmacology》2005,5(6):947-960
Recently, there has been a great interest in the effects of different types of n-6 polyunsaturated acids (n-6 PUFAs) upon the immune system and cancer development. However, the effects of n-6 PUFAs are still controversial and as yet undefined. The present study aimed to investigate the anti-tumor effects of n-6 PUFAs against EL4 thymoma and the associated immune mechanisms. To this, sesame oil, a vegetable oil enriched with n-6 PUFAs, or free linoleic acid (LA) were administered intraperitoneally into C57BL/6 mice before and after challenge with EL4 lymphoma cells. Treatment with either sesame oil or LA attenuated the growth and metastasis of EL4 lymphoma. The anti-tumor effect of LA was superior to that of sesame oil, and associated with an increase in the survival rate of the tumor-bearing mice. In addition, both sesame oil and LA showed dose-dependent anti-lymphoma growth in vitro. Treatment with LA generated significant increases in the anti-lymphoma cytolytic and cytostatic activities of T cells and macrophages, respectively, and enhanced production of IL-2 and IFN-gamma while decreased production of IL-4, IL-6 and IL-10. In summation, the results suggest that n-6 PUFAs, represented by LA, can attenuate EL4 lymphoma growth and metastasis through enhancing the specific and non-specific anti-tumor cytolytic activities and production of TH1 cytokines. These findings might be of great importance for a proper design of systemic nourishment with PUFAs emulsions for cancer patients. 相似文献
75.
Objective: Malposition or misplacement of gastric bands is a rare but recognised early complication of gastric band surgery. Malposition of the band would not normally result in significant weight loss after surgery. Case Report: To our knowledge, we report the first case in the English literature of a malpositioned gastric band encircling the pericardial fat pad only, who presented with delayed symptoms of dysphagia and gastro-oesophageal reflux resulting in significant weight loss (>60% of excess body weight) approximately 6 years after primary surgery. The patient underwent a water-soluble contrast study with antero-posterior views which was suggestive of a slipped band. However, on laparoscopy the band was found to be encircling the pericardial fat pad. Conclusion: We suggest that all contrast swallow studies for patients presenting with symptoms of gastric band slippage should include lateral views to exclude gastric band malposition, irrespective of the time of onset of symptoms after primary surgery. Copyright ? 2012 S. Karger GmbH, Freiburg. 相似文献
76.
Wilkinson RA Pincus SH Shepard JB Walton SK Bergin EP Labib M Teintze M 《Antimicrobial agents and chemotherapy》2011,55(1):255-263
The G-protein-coupled receptor CXCR4 acts as a coreceptor for human immunodeficiency virus type 1 (HIV-1) infection, as well as being involved in signaling cell migration and proliferation. Compounds that block CXCR4 interactions have potential uses as HIV entry inhibitors to complement drugs such as maraviroc that block the alternate coreceptor CCR5 or in cancer therapy. The peptide T140, which contains five arginine residues, is the most potent antagonist of CXCR4 developed to date. In a search for nonpeptide CXCR4 ligands that could inhibit HIV entry, three series of compounds were synthesized from 12 linear and branched polyamines with 2, 3, 4, 6, or 8 amino groups, which were substituted to produce the corresponding guanidines, biguanides, or phenylguanides. The resulting compounds were tested for their ability to compete with T140 for binding to the human CXCR4 receptor expressed on mammalian cells. The most effective compounds bound CXCR4 with a 50% inhibitory concentration of 200 nM, and all of the compounds had very low cytotoxicity. Two series of compounds were then tested for their ability to inhibit the infection of TZM-bl cells with X4 and R5 strains of HIV-1. Spermine phenylguanide and spermidine phenylguanide inhibited infection by X4 strains, but not by R5 strains, at low micromolar concentrations. These results support further investigation and development of these compounds as HIV entry inhibitors. 相似文献
77.
78.
79.
Specific Human Leukocyte Antigen Class II (HLA II) molecules associated with pemphigus vulgaris (PV), mucous membraine pemphigoid (MMP), and mixed connective tissue disease (MCTD) may react with multiple T cell epitopes within desmoglein 3 (Dsg 3), bullous pemphigoid antigen 2 (BPAG 2), and 70?kDa polypeptide small nuclear ribonucleoproteins (snRNP70) in autoantibody production. We report a group of patients with simultaneous occurrences of PV with MCTD, and MMP with MCTD. In one patient group, we performed serological studies to show presence of antibodies to Dsg 3, Dsg 1, and snRNP70 simultaneously. In the second group, we performed serological studies to show presence of antibodies to BPAG 1, BPAG 2, β4 integrin, and snRNP70 simultaneously. In both groups, HLA II genes were analyzed and the observations were consistent with previously described associations with PV, MMP, and MCTD. It is possible that HLA-DQβ1*0301 allele, present in 10 of 17 patients and DRβ1*04 in some of the others, may have the ability to bind to several relevant T cell epitopes in the snRNP70 molecule. We have utilized a computer model to demonstrate that HLA II-restricted T cell epitopes present within the known autoantigens may be capable of eliciting an immune response. While other explanations and mechanisms exist, the authors suggest that epitope spreading may be one possible mechanism, amongst others, that may result in the simultaneous presence of two separate pathogenic autoantibodies. 相似文献
80.
Bulters DO Santarius T Chia HL Parker RA Trivedi R Kirkpatrick PJ Kirollos RW 《Acta neurochirurgica》2011,153(2):295-303