全文获取类型
收费全文 | 117094篇 |
免费 | 7363篇 |
国内免费 | 943篇 |
专业分类
耳鼻咽喉 | 1288篇 |
儿科学 | 3299篇 |
妇产科学 | 2798篇 |
基础医学 | 14994篇 |
口腔科学 | 2719篇 |
临床医学 | 9239篇 |
内科学 | 27228篇 |
皮肤病学 | 2254篇 |
神经病学 | 10769篇 |
特种医学 | 4585篇 |
外国民族医学 | 23篇 |
外科学 | 17717篇 |
综合类 | 1688篇 |
一般理论 | 52篇 |
预防医学 | 6327篇 |
眼科学 | 1965篇 |
药学 | 9045篇 |
3篇 | |
中国医学 | 554篇 |
肿瘤学 | 8853篇 |
出版年
2023年 | 634篇 |
2022年 | 1427篇 |
2021年 | 2545篇 |
2020年 | 1596篇 |
2019年 | 2275篇 |
2018年 | 2815篇 |
2017年 | 2111篇 |
2016年 | 2297篇 |
2015年 | 2582篇 |
2014年 | 3430篇 |
2013年 | 4797篇 |
2012年 | 6664篇 |
2011年 | 6775篇 |
2010年 | 4308篇 |
2009年 | 3845篇 |
2008年 | 5984篇 |
2007年 | 6106篇 |
2006年 | 5809篇 |
2005年 | 5593篇 |
2004年 | 5858篇 |
2003年 | 5483篇 |
2002年 | 5446篇 |
2001年 | 3788篇 |
2000年 | 3748篇 |
1999年 | 3085篇 |
1998年 | 1297篇 |
1997年 | 1018篇 |
1996年 | 942篇 |
1995年 | 904篇 |
1994年 | 793篇 |
1993年 | 770篇 |
1992年 | 1846篇 |
1991年 | 1790篇 |
1990年 | 1539篇 |
1989年 | 1467篇 |
1988年 | 1348篇 |
1987年 | 1200篇 |
1986年 | 1196篇 |
1985年 | 1061篇 |
1984年 | 791篇 |
1983年 | 721篇 |
1982年 | 489篇 |
1981年 | 408篇 |
1979年 | 577篇 |
1978年 | 424篇 |
1975年 | 435篇 |
1974年 | 490篇 |
1973年 | 463篇 |
1972年 | 424篇 |
1971年 | 395篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
René Schwendimann Hugo Bühler Sabina De Geest Koen Milisen 《BMC health services research》2006,6(1):69
Background
Patient falls in hospitals are common and may lead to negative outcomes such as injuries, prolonged hospitalization and legal liability. Consequently, various hospital falls prevention programs have been implemented in the last decades. However, most of the programs had no sustained effects on falls reduction over extended periods of time. 相似文献62.
63.
A Londero B Langguth D De Ridder P Bonfils J-P Lefaucheur 《Clinical neurophysiology》2006,36(3):145-155
Subjective (non-recordable) tinnitus is the conscious perception of a phantom sound, and a very frequent, sometimes disabling, condition. Even if subjective tinnitus is often related to peripheral hearing loss, neurophysiological and functional imaging studies provide increasing evidence for an involvement both auditory and non-auditory central nervous pathways in the generation of tinnitus and related distress. Repetitive transcranial magnetic stimulation (rTMS) has been proposed to relieve tinnitus by reducing auditory cortex hyperexcitability associated with this condition. This paper will review the first clinical results reported in auditory cortex rTMS studies, with special reference to the pathophysiology of tinnitus processing and the mechanisms of action of rTMS. Although rTMS appears to be a very promising tool for the diagnosis and the treatment of tinnitus patients, available knowledge is still very limited at the moment. Further basic research and clinical studies are needed in order to optimize the parameters of stimulation (stimulus frequency, cortical target definition) and to validate the application of this technique in the management of patients with disabling tinnitus. 相似文献
64.
65.
Bruno Ferrari Antonio Pezzuto Lorenzo Barusi Francesco Coppola 《Gynecological endocrinology》2006,22(6):289-296
The aim of the present study was to investigate the effect of gonadotropin-releasing hormone (GnRH) antagonists (GnRH-ant) on follicular fluid (FF) insulin-like growth factor-I (IGF-I) and FF vascular endothelial growth factor (VEGF) levels. Sixty women undergoing assisted reproduction were randomized and assigned to two different GnRH analog regimens: GnRH agonist (GnRH-a) and GnRH-ant. FF VEGF and FF IGF-I concentrations were significantly increased in the patients treated with GnRH-ant (p < 0.001). In the same patients we observed a statistically significant reduction in serum luteinizing hormone (LH) and estradiol (E2) levels (p < 0.001 and p < 0.05, respectively), FF E2 and FF androstenedione levels (p < 0.05 and p < 0.001, respectively), as well as a reduction in the number of pregnancies although this was not statistically significant. In the GnRH-ant group, FF VEGF levels were positively correlated with FF IGF-I levels, and both were negatively correlated with serum LH levels. The increase in FF IGF-I and FF VEGF levels in women treated with GnRH-ant could be explained by a deleterious follicular environment in response to profound suppression of LH and E2 levels. 相似文献
66.
从土藿香根中得到两个二萜化合物,藿香酚(2)及异藿香酚(3)。经光谱解析(IR,UV,HRMS及NMR谱),确定它们的结构分别为11,14dihydroxy12methoxy19(4→3)abeoabieta4,(18),8,11,13tetraen7one(2)和11,14dihydroxy12methoxy19(4→3)abeoabieta3,8,11,13tetraen7one(3)藿香酚(2)为一新的化合物,而异藿香酚(3)系首次从天然界分离得到,二者为一对异构体。 相似文献
67.
C M Kyaw C R De Araujo M R Lima E G S Gondim M M Brígido L G Giugliano 《Infection, genetics and evolution》2003,3(2):111-117
Diffusely adhering Escherichia coli (E. coli) strains (DAEC) represent a potential cause of diarrhoea in infants, and the detection of type three secretion system (TTSS) genes in DAEC would substantiate their pathogenic nature. In this work, four isolates of DAEC, recovered from stools of diarrhoeic children, were analysed by PCR, in order to detect the presence of TTSS genes. Primers targeted to the escC, escJ, escN and escV, some of the most conserved TTSS genes in enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC), were used in order to verify the occurrence of homologous genes in our DAEC isolates. By this approach, we were able to characterise DNA fragments corresponding to putative escJ and escN genes in all DAEC isolates. Furthermore, DNA fragments homologous to the escC and escV genes were also amplified from all isolates. Besides the similarity found among the DAEC esc homologues with EPEC and EHEC esc genes, the nucleotide sequence analysis of the flanking regions of the amplified DNA fragments suggests that the putative DAEC esc genes are organised in the same manner as observed in EPEC and in EHEC strains. The results described here provide strong evidence for the presence of a TTSS in the DAEC strains analysed, implicating a pathogenic nature of these isolates. 相似文献
68.
R. De Zotti V. Patussi A. Fiorito F. Larese 《International archives of occupational and environmental health》1988,61(1-2):7-12
Summary Dock workers (n = 218) occupationally exposed to green coffee beans (GCB) were studied, using a specific questionnaire for allergic symptoms and skin tests for common and occupational allergens. Thirty-one workers (14.3%) complained of allergic symptoms of the eye, nose and bronchial system at the workplace. The prick tests, using both commercial allergens and specific extracts prepared from the most common types of coffee and their corresponding sacks, confirmed a sensitization in 21 workers (9.6%). A positive skin reaction to castor beans (CB) was found in nearly all these cases; in ten workers there was also a positive reaction to GCB allergens and in 14 cases prick tests were positive to extracts of sacks. There was a good concordance between prick tests and specific IgE for CB (95.0%) and also, but to a lesser extent, for GCB. The authors concluded that there is a significant risk of sensitization to CB and GCB allergens in dock workers occupied in handling green coffee bean, despite the fact that the exposure is not continuous. CB emerged as a common contaminant of GCB from various countries. For effective prevention, a modification of the methods of transport is required to avoid CB contamination to other products. Eliminating environmental dust during shipping operations is the most important preventive measure and it can be achieved by the use of containers, as some exporting countries are already doing. 相似文献
69.
Andrzej Zaba Beata Greb-Markiewicz Guido Sodano Francesco De Riccardis 《Journal of basic microbiology》1995,35(6):433-439
Unsaturated ketones ( 4 and 10 ) and epoxides ( 2–3 and 8–9 ) were the main products of biotransformation performed by means of Zoophthora (Neopandora) phyllobii. Enantiospecificity of both reactions leading to these compounds strongly depends on the distance of reacting fragment of molecule from the chiral center at C-1′. 相似文献
70.
Cyanoacrylate-based glues have been reported as producing dermatitis and bronchial asthma. The paper describes the case of a patient occupationally exposed to Loctite 406, who developed irritation of the skin and mucosae of the face and late bronchial asthma. Preventive measures for subjects exposed to cyanoacrylic instant glues are discussed. 相似文献