全文获取类型
收费全文 | 1210篇 |
免费 | 47篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 29篇 |
儿科学 | 21篇 |
妇产科学 | 15篇 |
基础医学 | 136篇 |
口腔科学 | 12篇 |
临床医学 | 95篇 |
内科学 | 225篇 |
皮肤病学 | 42篇 |
神经病学 | 140篇 |
特种医学 | 30篇 |
外科学 | 199篇 |
综合类 | 1篇 |
预防医学 | 34篇 |
眼科学 | 28篇 |
药学 | 129篇 |
中国医学 | 11篇 |
肿瘤学 | 122篇 |
出版年
2023年 | 3篇 |
2022年 | 18篇 |
2021年 | 32篇 |
2020年 | 24篇 |
2019年 | 31篇 |
2018年 | 43篇 |
2017年 | 22篇 |
2016年 | 34篇 |
2015年 | 40篇 |
2014年 | 48篇 |
2013年 | 58篇 |
2012年 | 90篇 |
2011年 | 103篇 |
2010年 | 35篇 |
2009年 | 31篇 |
2008年 | 81篇 |
2007年 | 76篇 |
2006年 | 75篇 |
2005年 | 63篇 |
2004年 | 68篇 |
2003年 | 80篇 |
2002年 | 41篇 |
2001年 | 25篇 |
2000年 | 25篇 |
1999年 | 21篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 9篇 |
1993年 | 5篇 |
1992年 | 13篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1968年 | 2篇 |
排序方式: 共有1269条查询结果,搜索用时 171 毫秒
1.
Is it possible to make a diagnosis of raw,heated, and baked egg allergy in children using cutoffs? A systematic review
下载免费PDF全文
![点击此处可从《Pediatric allergy and immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
2.
Alessandro Abbouda Paolo Tortorella Lucia Restivo Elisa Santoro Federica De Marco Maurizio La Cava 《Seminars in ophthalmology》2016,31(6):532-541
Purpose: To evaluate the rate and onset of intraoperative and postoperative complications post-phacoemulsification. Methods: One hundred sixty-two eyes of 145 patients with uveitis who underwent phacoemulsification between 2006 and 2009 were identified through surgical record review. Fifty-nine eyes of 46 patients met the inclusion criteria. Hazard ratio (HR) and Kaplan-Meier survival probability were calculated for each class of uveitis. Results: Macular edema (ME) resulted to be associated to chronic postoperative inflammation (r?=?0.6; p?=?0.00) and mostly related to patients who presented more than one postoperative relapse/year (r?=?0.2; p?=?0.02). Fuchs uveitis resulted to be a risk factor for posterior capsule opacification (PCO) (HR 3.36 IC95%1.0-10.5; p?=?0.03). Hypotony and elevated intraocular pressure (IOP) were detected in the anterior uveitis group (0.02 EY). Conclusion: The HR to develop ME was significantly related to chronic anterior uveitis. PCO and elevated IOP are most frequent in Fuchs uveitis. The postoperative visual acuity result was good among all the uveitis groups. 相似文献
3.
Giovanni Romussi Brunella Parodi Cosimo Pizza Nunziatina De Tommasi 《Archiv der Pharmazie》1994,327(10):643-645
Constituents of Fagaceae (Cupuliferae), XIX: Triterpene Saponins and Acylated Flavonoids from Quercus robur L. var. stenocarpa Beck. In addition to four known glycosides from leaves of Quercus robur L. var. stenocarpa Beck. a new triterpene saponin has been isolted and identified as 28-β-d-glucopyranosyl ester of the 2α,3β,19α-trihydroxy-olean-12-ene-24,28-dioic acid ( I ). 相似文献
4.
Inducible nitric oxide synthase expression in human colorectal cancer: correlation with tumor angiogenesis 总被引:15,自引:0,他引:15
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Cianchi F Cortesini C Fantappiè O Messerini L Schiavone N Vannacci A Nistri S Sardi I Baroni G Marzocca C Perna F Mazzanti R Bechi P Masini E 《The American journal of pathology》2003,162(3):793-801
To investigate the potential involvement of the nitric oxide (NO) pathway in colorectal carcinogenesis, we correlated the expression and the activity of inducible nitric oxide synthase (iNOS) with the degree of tumor angiogenesis in human colorectal cancer. Tumor samples and adjacent normal mucosa were obtained from 46 surgical specimens. Immunohistochemical expression of iNOS, vascular endothelial growth factor (VEGF), and CD31 was analyzed on paraffin-embedded tissue sections. iNOS activity and cyclic GMP levels were assessed by specific biochemical assays. iNOS protein expression was determined by Western blot analysis. iNOS and VEGF mRNA levels were evaluated using Northern blot analysis. Both iNOS and VEGF expressions correlated significantly with intratumor microvessel density (r(s) = 0.31, P = 0.02 and r(s) = 0.67, P < 0.0001, respectively). A significant correlation was also found between iNOS and VEGF expression (P = 0.001). iNOS activity and cyclic GMP production were significantly higher in the cancer specimens than in the normal mucosa (P < 0.0001 and P < 0.0001, respectively), as well as in metastatic tumors than in nonmetastatic ones (P = 0.002 and P = 0.04, respectively). Western and Northern blot analyses confirmed the up-regulation of the iNOS protein and gene in the tumor specimens as compared with normal mucosa. NO seems to play a role in colorectal cancer growth by promoting tumor angiogenesis. 相似文献
5.
Antibiotic Use in Crohn’s Disease 总被引:3,自引:0,他引:3
Prantera C Scribano ML Berto E Zannoni F 《BioDrugs : clinical immunotherapeutics, biopharmaceuticals and gene therapy》1997,8(4):293-306
On the assumption that bacteria in the gut may be a cause of symptoms and/or complications of Crohn's disease, various antibiotics are efficaciously employed in some affected patients. However, we do not know exactly why and how they are helpful. A possible explanation is that one or several bacterial species may have a primary role in the aetiology of Crohn's disease, but this is not supported by the data in our possession. Another hypothesis is that intestinal bacteria may cause flare-up of the disorder, either by inducing intestinal lesions or by an interaction with the immune system, but we know today that specific pathogens can cause flares only in a minority of cases. On the contrary, there is considerable evidence that the intestinal microflora and its products may amplify and perpetuate inflammation in Crohn's disease. Despite the fact that few controlled trials have been conducted, and have shown inconclusive results, antibiotics are widely employed for improving symptoms and for inducing remission of active phases. At present, a combination of metronidazole and ciprofloxacin, active against many enteric bacteria, has proved to be effective in the treatment of Crohn's disease complications. This therapy also seems to be effective in acute flares as an alternative to, or in combination with, corticosteroids. 相似文献
6.
Genetic instability in superficial bladder cancer and adjacent mucosa: an interphase cytogenetic study 总被引:5,自引:0,他引:5
Cianciulli AM Leonardo C Guadagni F Marzano R Iori F De Nunzio C Franco G Merola R Laurenti C 《Human pathology》2003,34(3):214-221
A systematic analysis of both tumors and the surrounding urothelium to help identify what lies behind the mechanism of multifocal tumor development has not yet been performed. In this study we investigated chromosome 1, 7, 9, and 17 aneusomy in 25 superficial papillary carcinomas and in 51 tissue samples taken from sites of macroscopically uninvolved urothelium surrounding the tumors, using the fluorescence in situ hybridization method. Our data demonstrated a close genetic relationship between all examined tumors and normal-appearing mucosa. Numeric aberrations of chromosomes 1, 7, 9, and 17 were found to exhibit similar patterns in all analyzed specimens, although with different frequencies. 相似文献
7.
8.
9.
Marta Giamberini Eugenio Amendola Cosimo Carfagna 《Macromolecular chemistry and physics.》1997,198(10):3185-3196
Lightly crosslinked liquid crystalline epoxy resins were synthesized by reacting rigid rod epoxy-terminated molecules with decanedioic acid (SA). The obtained networks exhibited a smectic phase even in the case of 2,6-bis(2,3-epoxypropoxy)naphthalene, whose aspect ratio is very low. Upon application of uniaxial stress, a smectic phase was surprisingly obtained also for the system obtained by reacting p-bis(2,3-epoxypropoxy)-benzene (QH), whose aspect ratio is practically equal to one, and SA. Stretching of the smectic samples above the glass transition temperature determines orientation of polymer chains, yielding considerably high values of the order parameter S. Thermomechanical analysis showed, for one of these systems, that stretching induces a shift of the isotropization temperature to higher values. 相似文献
10.
Tortorella C Piazzolla G Spaccavento F Jirillo E Antonaci S 《Mechanisms of ageing and development》1999,110(3):283-205
Spontaneous as well as Fas-induced polymorphonuclear cell apoptosis is unchanged in the elderly. However, a weak responsiveness to antiapoptotic signals elicited by proinflammatory molecules has been reported in neutrophils isolated from aged humans. To gain insight into this field, here we have evaluated the role of oxidative metabolism and cyclic AMP (cAMP) signaling on age-related neutrophil apoptotic cell death. Results show that although superoxide dismutase (SOD), added exogenously to cell cultures, is able to prolong neutrophil survival in both young and aged individuals, high amounts of the enzyme are further effective in cell cultures of young donors only. Notably, the addition of catalase gives rise to a more striking, yet comparable, inhibition of neutrophil-programmed cell death in both groups of subjects. Furthermore, even low amounts of catalase are enough to restore a normal apoptotic outcome in SOD-treated cell cultures of old donors. Unlike the oxidative metabolism, cAMP signaling activation does not reveal any difference in the apoptotic response of neutrophils isolated from young and aged donors. Thus, supplementation of cell cultures with prostaglandin E2, dibutyryl cAMP or, to a lesser degree, forskolin results in a dose-dependent inhibition of DNA cleavage product appearance in both groups of subjects. The data outline that an impairment of neutrophil antioxidant shield, leading to an augmented cell oxidative load, is likely to occur as a feature of age. This may increase the apoptotic rate of stimulated cells, which may in turn account for the increased susceptibility of elderly individuals to life-threatening infections. 相似文献