全文获取类型
收费全文 | 4786篇 |
免费 | 309篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 36篇 |
儿科学 | 209篇 |
妇产科学 | 82篇 |
基础医学 | 698篇 |
口腔科学 | 112篇 |
临床医学 | 357篇 |
内科学 | 1155篇 |
皮肤病学 | 59篇 |
神经病学 | 398篇 |
特种医学 | 230篇 |
外科学 | 706篇 |
综合类 | 148篇 |
预防医学 | 263篇 |
眼科学 | 48篇 |
药学 | 330篇 |
中国医学 | 52篇 |
肿瘤学 | 244篇 |
出版年
2023年 | 25篇 |
2022年 | 60篇 |
2021年 | 100篇 |
2020年 | 64篇 |
2019年 | 98篇 |
2018年 | 130篇 |
2017年 | 78篇 |
2016年 | 109篇 |
2015年 | 109篇 |
2014年 | 155篇 |
2013年 | 166篇 |
2012年 | 271篇 |
2011年 | 266篇 |
2010年 | 193篇 |
2009年 | 167篇 |
2008年 | 198篇 |
2007年 | 223篇 |
2006年 | 247篇 |
2005年 | 211篇 |
2004年 | 200篇 |
2003年 | 205篇 |
2002年 | 150篇 |
2001年 | 130篇 |
2000年 | 126篇 |
1999年 | 124篇 |
1998年 | 88篇 |
1997年 | 97篇 |
1996年 | 88篇 |
1995年 | 59篇 |
1994年 | 52篇 |
1993年 | 46篇 |
1992年 | 89篇 |
1991年 | 75篇 |
1990年 | 63篇 |
1989年 | 85篇 |
1988年 | 61篇 |
1987年 | 61篇 |
1986年 | 53篇 |
1985年 | 48篇 |
1984年 | 33篇 |
1983年 | 24篇 |
1982年 | 29篇 |
1981年 | 16篇 |
1980年 | 30篇 |
1979年 | 36篇 |
1978年 | 13篇 |
1977年 | 21篇 |
1976年 | 13篇 |
1973年 | 12篇 |
1966年 | 15篇 |
排序方式: 共有5127条查询结果,搜索用时 31 毫秒
1.
2.
Background:
The results of a pilot colorectal cancer screening programme by biennial immunochemical faecal occult blood test (FOBT) are reported.Methods:
All residents aged between 50 and 69 years in the Italian province of Lecco were invited to have a FOBT. Those with a positive result were offered colonoscopy. FOBT uptake and compliance with colonoscopy were assessed. Detection rate and positive predictive value (PPV) for cancer and adenoma were calculated. Tumour stages were compared between screen‐detected cancers and other colorectal cancers diagnosed within the target age group.Results:
Some 38 693 (49·6 per cent) of 78 083 individuals had a FOBT and 2392 (6·2 per cent) had a positive result. Colorectal cancer was diagnosed in 4·6 per cent and advanced adenoma in 32·7 per cent. PPVs were 4·0 per cent for cancer, 28·1 per cent for advanced adenoma and 36·6 per cent for any adenoma. There was a significant difference in incidence of stage III/IV disease between screened and non‐screened cohorts. Compliance for colonoscopy was 92·0 per cent. Major determinants of compliance were age less than 59 years, female sex, high education level and non‐manual work.Conclusion:
These results justify extension of colorectal cancer screening to other regions of Italy. Copyright © 2009 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. 相似文献3.
M Chiavarelli R Chiavarelli A Macchiarelli A Carpi B Marino 《The Annals of thoracic surgery》1986,41(5):535-541
The potential additive protective effect provided by nifedipine to the University of Alabama Hospitals cardioplegia solution (ACS) was assessed with the use of a guinea pig heart-lung model of cardiopulmonary bypass and ischemic arrest. The addition of nifedipine consistently enhanced the protective properties of ACS infused at 37 degrees C; functional recovery was similar to that observed with cold ACS. Despite the additional protection under normothermic conditions, nifedipine did not improve recovery after infusion at 4 degrees C. The abolition by hypothermia of the protective effects of nifedipine suggests a similarity in action between nifedipine and hypothermic protection. The interaction between ACS and nifedipine was studied on bovine coronary arteries in vitro. Nifedipine caused a marked reduction in the coronary vasoconstricting effect of ACS, both under normothermic and hypothermic conditions. The use of nifedipine in cardioplegia may provide additional protection when uneven distribution of the cardioplegic solution is expected and hypothermic protection is unreliable. 相似文献
4.
D M Morris R Haskins A A Marino R P Misra S Rogers S Fronczak J A Albright 《Surgery》1990,107(6):627-631
Carbon in the form of 8-micron fibers induces growth of connective tissue. The purpose of this study was to measure and histologically characterize tissue ingrowth occurring in carbon fibers implanted for up to 12 months in abdominal-wall defects in rats, compared with polypropylene mesh. Carbon fibers induced significantly more tissue ingrowth than polypropylene mesh at 6 to 12 months postoperatively. The predominant tissues associated with carbon fibers and polypropylene mesh were dense connective tissue and fat, respectively. Fragmentation of the implants did not occur, and implant debris was not found in the regional lymph nodes. Carbon fibers are potentially useful for reinforcing abdominal-wall defects. 相似文献
5.
F. Marino M. Cosentino F. De Ponti C. Giaroni L. Somaini R. Bombelli M. Ferrari A.J. Aasen S. Lecchini G. Frigo 《Autonomic & autacoid pharmacology》1997,17(6):365-372
1 The present study examined the role of muscarinic receptors in the modulation of noradrenaline (NA) release in the guinea-pig isolated distal colon. The spontaneous endogenous NA overflow assayed by HPLC-ED was taken as an index of NA release from enteric noradrenergic nerve terminals. 2 Physostigmine (10 μm ) significantly enhanced spontaneous endogenous NA overflow. Hyoscine (muscarinic antagonist), (R)-(-)-trihexyphenidyl and telenzepine (M1-selective antagonists), and 11[[2-[(diethylamino)methyl]-1-piperydil]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one (AF-DX 116, M2-selective antagonist) inhibited NA overflow in a concentration dependent manner, with the following EC50 values: 131.74 (18.19–953.96), 101.62 (58.83–175.60), 150 (60–330), 30 (5–170) nm , respectively. 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP, M1- and M3- selective antagonist) had no significant effect up to 100 μm . 3 The muscarinic agonist oxotremorine inhibited NA overflow in a concentration dependent manner, with an EC50 value of 0.67 (0.30–1.51) μm . The response to oxotremorine was inhibited by muscarinic antagonists with the following order of potency: hyoscine = (R)-(-)-trihexyphenidyl = telenzepine > 4-DAMP >> AF-DX 116. 4 In the presence of 3 μm tetrodotoxin (TTX), the effect of oxotremorine and 4-DAMP was unchanged, while hyoscine, (R)-(-)-trihexyphenidyl, telenzepine and AF-DX 116, instead of inhibiting, significantly enhanced NA overflow. 5 The present results indicate that, in the guinea-pig colon, endogenous acetylcholine sustains spontaneous NA release by activating muscarinic receptors possibly located on interneurones. In addition, inhibitory muscarinic receptors may exist on adrenergic terminals. 相似文献
6.
Suppurative corneal ulceration in Bangladesh 总被引:8,自引:0,他引:8
AAS Dunlop MB BS ED Wright MRCPath † SA Howlader‡ I Nazrul‡ R Husain‡ K McClellan FRACO § FA Billson FRACO § 《Clinical & experimental ophthalmology》1994,22(2):105-110
Suppurative keratitis is an important preventable cause of blindness, particularly in the developing world. This study analyses 142 cases of suppurative keratitis referred to Chittagong Eye Infirmary, Bangladesh. Some 53.5% of cases were bacterial and 35.9% were fungal. The five most common pathogens were: Pseudomonas sp. 24%, Streptococcus pneumoniae 17%, Aspergillus sp. 13%, Fusarium sp. 7% and Curvularia sp. 6%. Gram stain and culture results were consistent in 62.6% of cases. Previous antibiotic treatment was a significant factor for failure of culture isolation and less so for Gram stain failure. On Gram stain, 55.9% of pseudomonal cases were missed, but only 2% of fungal cases were missed. Over all, Gram stain had a sensitivity of 62% and positive predictive value of 84% for bacterial cases, and 98% and 94% for fungal cases, respectively. Fungal ulcers were typically filamentous, but an antecedent history of trauma was not common. The most frequent injury was due to rice grains, but the inoculum appeared to be introduced during eye washing with contaminated water. Pseudomonal ulcers occurred most frequently in the monsoon season, and Fusarium cases were seen only in the hot, dry season. 相似文献
7.
8.
9.
Palliation of cardiac malformations associated with right isomerism (asplenia syndrome) in infancy 总被引:1,自引:0,他引:1
R Di Donato D di Carlo C Squitieri E Rossi A Ammirati B Marino C Marcelletti 《The Annals of thoracic surgery》1987,44(1):35-39
Right isomerism is characterized by the combination of an obstructed pulmonary outflow tract and a total anomalous pulmonary venous connection (TAPVC), which is obstructed in nearly half of the patients. Fourteen patients less than 2 years of age with right isomerism have been seen in our unit. Thirteen of them underwent palliation consisting of a systemic-pulmonary shunt (10 patients) or a combination of shunt and TAPVC repair (3). There were 7 hospital deaths (54%). The presence of obstructed pulmonary venous drainage was the major risk factor in the surgical treatment of these complex cardiac anomalies (p less than .02). Guidelines for the palliative management of right isomerism are suggested. 相似文献