全文获取类型
收费全文 | 3774篇 |
免费 | 384篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 184篇 |
妇产科学 | 69篇 |
基础医学 | 491篇 |
口腔科学 | 78篇 |
临床医学 | 382篇 |
内科学 | 693篇 |
皮肤病学 | 61篇 |
神经病学 | 394篇 |
特种医学 | 286篇 |
外科学 | 396篇 |
综合类 | 97篇 |
一般理论 | 2篇 |
预防医学 | 442篇 |
眼科学 | 114篇 |
药学 | 253篇 |
1篇 | |
肿瘤学 | 232篇 |
出版年
2022年 | 23篇 |
2021年 | 51篇 |
2020年 | 34篇 |
2019年 | 53篇 |
2018年 | 71篇 |
2017年 | 38篇 |
2016年 | 45篇 |
2015年 | 66篇 |
2014年 | 83篇 |
2013年 | 134篇 |
2012年 | 153篇 |
2011年 | 173篇 |
2010年 | 130篇 |
2009年 | 122篇 |
2008年 | 135篇 |
2007年 | 155篇 |
2006年 | 139篇 |
2005年 | 141篇 |
2004年 | 116篇 |
2003年 | 140篇 |
2002年 | 102篇 |
2001年 | 119篇 |
2000年 | 96篇 |
1999年 | 112篇 |
1998年 | 120篇 |
1997年 | 106篇 |
1996年 | 91篇 |
1995年 | 90篇 |
1994年 | 64篇 |
1993年 | 74篇 |
1992年 | 61篇 |
1991年 | 78篇 |
1990年 | 72篇 |
1989年 | 105篇 |
1988年 | 86篇 |
1987年 | 65篇 |
1986年 | 53篇 |
1985年 | 72篇 |
1984年 | 56篇 |
1983年 | 47篇 |
1982年 | 39篇 |
1981年 | 44篇 |
1980年 | 42篇 |
1978年 | 35篇 |
1977年 | 37篇 |
1976年 | 29篇 |
1975年 | 27篇 |
1974年 | 27篇 |
1971年 | 21篇 |
1970年 | 21篇 |
排序方式: 共有4179条查询结果,搜索用时 15 毫秒
1.
Lesley A. Inker Morgan E. Grams Andrew S. Levey Josef Coresh Massimo Cirillo John F. Collins Ron T. Gansevoort Orlando M. Gutierrez Takayuki Hamano Gunnar H. Heine Shizukiyo Ishikawa Sun Ha Jee Florian Kronenberg Martin J. Landray Katsuyuki Miura Girish N. Nadkarni Carmen A. Peralta Dietrich Rothenbacher Mark Woodward 《American journal of kidney diseases》2019,73(2):206-217
2.
G B Hopkinson D A Woodward N Prasad B R Bullen 《Annals of the Royal College of Surgeons of England》1983,65(5):323-324
The presence of accessory channels between the liver and extrahepatic bile ducts has long been recognised by anatomists and the division of such ducts may be a cause of bile leakage following cholecystectomy. However, visualisation of accessory bile ducts at operation is difficult as they are often small and sometimes less than 1 mm in diameter. Cholangiography has been used to help in the identification of accessory ducts in 50 patients included in a prospective trial. X-rays were taken after dissection of the gall bladder from its bed and extravasation of contrast was seen on five occasions (10%) suggesting leakage from divided accessory ducts. The identification of damage to accessory bile ducts in 10% of patients suggests that this may occur more frequently than previously supposed. 相似文献
3.
Abstract: Native chemical ligation has proven to be a powerful method for the synthesis of small proteins and the semisynthesis of larger ones. The essential synthetic intermediates, which are C‐terminal peptide thioesters, cannot survive the repetitive piperidine deprotection steps of Nα‐9‐fluorenylmethoxycarbonyl (Fmoc) chemistry. Therefore, peptide scientists who prefer to not use Nα‐t‐butyloxycarbonyl (Boc) chemistry need to adopt more esoteric strategies and tactics in order to integrate ligation approaches with Fmoc chemistry. In the present work, side‐chain and backbone anchoring strategies have been used to prepare the required suitably (partially) protected and/or activated peptide intermediates spanning the length of bovine pancreatic trypsin inhibitor (BPTI). Three separate strategies for managing the critical N‐terminal cysteine residue have been developed: (i) incorporation of Nα‐9‐fluorenylmethoxycarbonyl‐S‐(N‐methyl‐N‐phenylcarbamoyl)sulfenylcysteine [Fmoc‐Cys(Snm)‐OH], allowing creation of an otherwise fully protected resin‐bound intermediate with N‐terminal free Cys; (ii) incorporation of Nα‐9‐fluorenylmethoxycarbonyl‐S‐triphenylmethylcysteine [Fmoc‐Cys(Trt)‐OH], generating a stable Fmoc‐Cys(H)‐peptide upon acidolytic cleavage; and (iii) incorporation of Nα‐t‐butyloxycarbonyl‐S‐fluorenylmethylcysteine [Boc‐Cys(Fm)‐OH], generating a stable H‐Cys(Fm)‐peptide upon cleavage. In separate stages of these strategies, thioesters are established at the C‐termini by selective deprotection and coupling steps carried out while peptides remain bound to the supports. Pilot native chemical ligations were pursued directly on‐resin, as well as in solution after cleavage/purification. 相似文献
4.
5.
6.
Pyomyositis: characteristics at CT and MR imaging 总被引:9,自引:0,他引:9
7.
AJ Larner MRCP 《International journal of clinical practice》1994,48(5):272-274
SUMMARY A case is reported of pseudohyperphosphataemia in association with a monoclonal gammopathy of undetermined significance. 相似文献
8.
9.
10.
D De AJ Kanwar S Handa 《Journal of the European Academy of Dermatology and Venereology》2006,20(7):853-859
BACKGROUND: Diagnosis of atopic dermatitis (AD) depends on clinical features because no definitive diagnostic test exists. Criteria proposed by Hanifin and Rajka (Acta Derm Venereol (Stockh) 1980; Suppl 92: 44-47) were acceptable for hospital-based studies but were found not to be suitable for field studies. A UK working party formulated clinical diagnostic criteria that could be used in both hospital and epidemiological settings. Validation studies of the criteria showed widely variable results, probably due to different clinical settings and ethnicity. AIM AND OBJECTIVE: This study was undertaken to validate Hanifin and Rajka's criteria and to assess the comparative efficacy of their criteria and the UK working party's diagnostic criteria in the diagnosis of AD in a hospital setting in North India. SUBJECTS AND METHODS: This study serially included 101 patients with AD and 48 controls of paediatric age group. The study period was from July 2003 to December 2004. RESULTS: Hanifin and Rajka's criteria (sensitivity 96%, specificity 93.75%, positive predictive value 97% (PPV) and negative predictive value (NPV) 91.84%) had a statistical advantage over the UK working party's diagnostic criteria (sensitivity 86%, specificity 95.83%, PPV 97.75% and NPV 76.67%), with a P-value < 0.005. 相似文献