全文获取类型
收费全文 | 4974篇 |
免费 | 345篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 170篇 |
妇产科学 | 130篇 |
基础医学 | 781篇 |
口腔科学 | 90篇 |
临床医学 | 403篇 |
内科学 | 1221篇 |
皮肤病学 | 98篇 |
神经病学 | 544篇 |
特种医学 | 130篇 |
外科学 | 706篇 |
综合类 | 18篇 |
一般理论 | 2篇 |
预防医学 | 280篇 |
眼科学 | 50篇 |
药学 | 377篇 |
中国医学 | 15篇 |
肿瘤学 | 284篇 |
出版年
2023年 | 34篇 |
2022年 | 32篇 |
2021年 | 137篇 |
2020年 | 92篇 |
2019年 | 140篇 |
2018年 | 161篇 |
2017年 | 99篇 |
2016年 | 136篇 |
2015年 | 150篇 |
2014年 | 168篇 |
2013年 | 210篇 |
2012年 | 335篇 |
2011年 | 343篇 |
2010年 | 187篇 |
2009年 | 164篇 |
2008年 | 257篇 |
2007年 | 286篇 |
2006年 | 283篇 |
2005年 | 247篇 |
2004年 | 240篇 |
2003年 | 226篇 |
2002年 | 189篇 |
2001年 | 118篇 |
2000年 | 117篇 |
1999年 | 107篇 |
1998年 | 47篇 |
1997年 | 38篇 |
1996年 | 35篇 |
1995年 | 21篇 |
1994年 | 20篇 |
1993年 | 16篇 |
1992年 | 80篇 |
1991年 | 69篇 |
1990年 | 54篇 |
1989年 | 62篇 |
1988年 | 41篇 |
1987年 | 46篇 |
1986年 | 37篇 |
1985年 | 38篇 |
1984年 | 22篇 |
1983年 | 22篇 |
1982年 | 18篇 |
1980年 | 19篇 |
1979年 | 33篇 |
1978年 | 12篇 |
1977年 | 15篇 |
1974年 | 11篇 |
1973年 | 12篇 |
1967年 | 10篇 |
1966年 | 15篇 |
排序方式: 共有5344条查询结果,搜索用时 161 毫秒
1.
2.
3.
4.
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
5.
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6.
Rebecca Voltan Arianna Castaldello Egidio Brocca-Cofano Rita De Michele Chiara Triulzi Giuseppe Altavilla Luisa Tondelli Michele Laus Katia Sparnacci Eva Reali Riccardo Gavioli Barbara Ensoli Antonella Caputo 《Vaccine》2009
Cationic block copolymers spontaneously assemble via electrostatic interactions with DNA molecules in aqueous solution giving rise to micellar structures that protect the DNA from enzymatic degradation both in vitro and in vivo. In addition, we have previously shown that they are safe, not immunogenic and greatly increased antigen-specific CTL responses following six intramuscular inoculations of a very low dose (1 μg) of the vaccine DNA as compared to naked DNA. Nevertheless, they failed to elicit detectable humoral responses against the antigen. To gain further insight in the potential application of this technology, here we show that a shorter immunization protocol based on two DNA intramuscular inoculations of 1 μg of DNA delivered by these copolymers and a protein boost elicits in mice broad (both humoral and cellular) and long-lasting responses and increases the antigen-specific Th1-type T cell responses and CTLs as compared to priming with naked DNA. These results indicate that cationic block copolymers represent a promising adjuvant and delivery technology for DNA vaccination strategies aimed at combating intracellular pathogens. 相似文献
7.
Francesca Borrelli Nicola Borbone Raffaele Capasso Domenico Montesano Simona De Marino Gabriella Aviello Giovanni Aprea Stefania Masone Angelo A. Izzo 《Journal of ethnopharmacology》2009
Ethnopharmacological importance
Celastrus paniculatus Willd. (Celastraceae) is an Ayurvedic remedy used for the treatment of a number of diseases, including bowel spasms.Aim of the study
To investigate the mode of the relaxing action of a methanolic extract prepared from the seeds of Celastrus paniculatus (CPE, 0.0001–10 μg/mL) in the rat ileum and to try to confirm on human tissues the intestinal pharmacological activity of the extract.Materials and methods
The relaxant effect of CPE was studied in vitro by evaluating its effect on the spontaneous contractions of the isolated ileum.Results
CPE exerted a tetrodotoxin- and ω-conotoxin-resistant inhibitory effect on rat ileum motility (IC50: 0.24 ± 0.02 μg/mL; Emax: 99.0 ± 0.60%). The inhibitory effect was reduced by nifedipine but not by cyclopiazonic acid. Experiments with specific antagonists enabled us to exclude the involvement of the main endogenous spasmogenic (i.e. acetylcholine and tachykinins) and relaxing (noradrenaline, nitric oxide, ATP) compounds. CPE also relaxed the isolated human ileum (IC50: 0.26 ± 0.02 μg/mL; Emax: 99.1 ± 0.46%).Conclusion
It is concluded that (i) CPE exerted a powerful myogenic and L-type Ca2+-dependent relaxing effect in the isolated rat ileum and that (ii) the human ileum is sensitive to the inhibitory effect of CPE. If confirmed in vivo, our data could explain the traditional use of this herb in the treatment of intestinal spasms. 相似文献8.
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
9.
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
10.
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