全文获取类型
收费全文 | 11165篇 |
免费 | 717篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 302篇 |
儿科学 | 277篇 |
妇产科学 | 302篇 |
基础医学 | 1577篇 |
口腔科学 | 440篇 |
临床医学 | 925篇 |
内科学 | 2611篇 |
皮肤病学 | 206篇 |
神经病学 | 1268篇 |
特种医学 | 222篇 |
外科学 | 1016篇 |
综合类 | 21篇 |
一般理论 | 6篇 |
预防医学 | 650篇 |
眼科学 | 133篇 |
药学 | 701篇 |
1篇 | |
中国医学 | 36篇 |
肿瘤学 | 1239篇 |
出版年
2024年 | 55篇 |
2023年 | 125篇 |
2022年 | 276篇 |
2021年 | 436篇 |
2020年 | 282篇 |
2019年 | 318篇 |
2018年 | 350篇 |
2017年 | 289篇 |
2016年 | 353篇 |
2015年 | 373篇 |
2014年 | 499篇 |
2013年 | 603篇 |
2012年 | 932篇 |
2011年 | 1048篇 |
2010年 | 518篇 |
2009年 | 454篇 |
2008年 | 787篇 |
2007年 | 720篇 |
2006年 | 641篇 |
2005年 | 671篇 |
2004年 | 604篇 |
2003年 | 548篇 |
2002年 | 481篇 |
2001年 | 58篇 |
2000年 | 34篇 |
1999年 | 52篇 |
1998年 | 88篇 |
1997年 | 61篇 |
1996年 | 44篇 |
1995年 | 46篇 |
1994年 | 34篇 |
1993年 | 32篇 |
1992年 | 23篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1988年 | 8篇 |
1987年 | 2篇 |
1986年 | 15篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1974年 | 5篇 |
1973年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Alessandro Rambaldi Alessandra Iurlo Alessandro M. Vannucchi Bruno Martino Attilio Guarini Marco Ruggeri Nikolas von Bubnoff Marianna De Muro Mary Frances McMullin Stefania Luciani Vincenzo Martinelli Axel Nogai Vittorio Rosti Alessandra Ricco Paolo Bettica Sara Manzoni Silvia Di Tollo 《Blood cancer journal》2021,11(3)
2.
Marica Ferri Sonia Dias Alessandra Bo Danilo Ballotta Roland Simon Giuseppe Carrá 《Drugs (Abingdon, England)》2018,25(2):198-204
Background: The EMCDDA, through its network of National Focal Points, collects information on the quality assurance systems for drugs-related interventions across European countries. European National Drug Strategies include recommendations for systems and approaches for the assurance of the quality of interventions.Methods: We searched National Drug Strategies for elements related to quality assurance in drug demand reduction and summarised information through questionnaires administered to the EMCDDA Network of National Focal Points.Results: In total, 15 National Drug Strategies and 60 questionnaires were analysed. Almost all the strategies include quality-related topics. Frequently, the Ministry of Health leads quality assurance although sometimes jointly with the Ministries of Education, Labour, Family and Social Welfare. Accreditation systems are common, but implemented in different ways. Training and education are widely provided, for the vast majority of countries, consisting of short-term training to keep professionals updated. Guidelines and Standards are gathering momentum as the major tools for the implementation of evidence-based recommendations and are usually available across countries.Conclusions: Although the evidence base for interventions in drug demand reduction is becoming available and accepted, attention needs to be given to implementation issues. The European countries are rapidly moving towards paying greater attention to the quality of interventions. 相似文献
3.
Paolo Armanetti Salvador Pocoví-Martínez Alessandra Flori Cinzia Avigo Domenico Cassano Luca Menichetti Valerio Voliani 《Nanomedicine : nanotechnology, biology, and medicine》2018,14(6):1787-1795
Ultrasound (US) imaging is a well-established diagnostic technique to image soft tissues in real time, while photoacoustic (PA) is an emerging imaging technique employed to collect molecular information. Integration of PA and US imaging provides complementary information enhancing diagnostic accuracy without employing ionizing radiations. The development of contrast agents able to combine PA and US features is pivotal to improve the significance of PAUS imaging and for PAUS-guided treatment of neoplasms. Here, we demonstrate in relevant ex-vivo models that disassembling passion fruit-like nano-architectures (pfNAs) can be employed in PAUS imaging. pfNAs are composed by silica nanocapsules comprising aggregates of commercial NIR-dyes-modified polymers and ultrasmall gold nanoparticles. The intrinsic US and PA features of pfNAs have been fully characterized and validated in tissue-mimicking materials and in ex vivo preparations. Moreover, the application of a multi-parametric approach has allowed the increase of information extrapolated from collected images for a fine texture analysis. 相似文献
4.
Negrini Simone Magnani Ottavia Matucci-Cerinic Marco Carignola Renato Data Valeria Montabone Erika Santaniello Alessandro Adorni Giuditta Murdaca Giuseppe Puppo Francesco Indiveri Francesco Della Rossa Alessandra D’Ascanio Anna Barsotti Simone Giuggioli Dilia Ferri Clodoveo Lumetti Federica Bosello Silvia Laura Canestrari Giovanni Bellando Randone Silvia Bruni Cosimo Guiducci Serena Battaglia Elisabetta De Andres Maria Ilenia Russo Alessandra Azzurra Beretta Lorenzo 《Clinical and experimental medicine》2019,19(3):357-366
Clinical and Experimental Medicine - Vasculopathy is a crucial feature of systemic sclerosis (SSc), and Raynaud’s phenomenon (RP) and digital ulcers (DU) have a deep impact on the quality of... 相似文献
5.
Sara Massironi Alessandra Zilli Alessandra Elvevi Pietro Invernizzi 《Autoimmunity reviews》2019,18(3):215-222
Chronic autoimmune atrophic gastritis (CAAG) is an organ-specific autoimmune disease, which affects the corpus–fundus gastric mucosa. Although it has been described for several years, the real pathophysiological mechanisms, the natural history and the possible neoplastic complications are not completely known. Atrophy of the gastric mucosa is the endpoint of the chronic processes, with the loss of glandular cells and their replacement by intestinal-type epithelium, pyloric-type glands, and fibrous tissue. As a consequence, hydrochloric acid, pepsin and intrinsic-factor is impaired resulting in pernicious anemia. The exact causal agent is not yet known, but both genetic and environmental factors seem to play a decisive role.Moreover, the clinical onset may assume different characteristics; differently from what previously observed, recent evidence has reported the onset of CAAG at a younger age, frequently with iron deficiency anemia or upper gastro-intestinal symptoms.The diagnosis of CAAG might be challenging and usually requires the combination of clinical, serological and histopathologic data; moreover, CAAG patients are often misdiagnosed as refractory to HP eradication therapy, probably because achlorhydria might allow urease-positive bacteria other than H pylori to colonize the stomach, causing positive 13C-urea breath test results.However, biopsy is the most reliable method to evaluate the presence of metaplastic atrophic gastritis. In order to assess the severity of gastric atrophy and intestinal metaplasia, OLGA and OLGIM staging systems have been proposed and seem to correlate with the risk of developing gastric adenocarcinoma. Indeed, CAAG represents a pre-neoplastic condition, as patients with CAAG are very likely to develop either type-1 gastric neuroendocrine tumors and gastric adenocarcinomas, as well as several other neoplastic diseases. To date, the need, the intervals and cost-effectiveness of endoscopic/histological surveillance for patients with CAAG/pernicious anemia are yet to be established. 相似文献
6.
Alessandra Ferrario 《Value in health》2018,21(7):809-821
Objectives
First, to quantify the median time from European Union (EU)-wide approval to first use (launch) for a sample of cancer medicines and number of launches in Belgium, Estonia, Scotland, and Sweden as of June 2015. Second, to assess whether longer times to launch or lack of launches affected medicines with high or low expected additional clinical benefit. Third, to identify possible determinants of the probability of a cancer medicine to be launched.Methods
Correlation between time to launch and a set of variables hypothesized to affect launch was tested using a complementary log-log model for a sample of 46 cancer medicines that obtained EU-wide marketing authorization between 2000 and 2014.Results
In median, for a sample of 24 cancer medicines that obtained marketing authorization between 2010 and 2014, the expected time from EU-wide marketing authorization to first use of a medicine was shortest in Sweden, 3.1 months, followed by Scotland (9.3 months), Belgium (14.8 months), and Estonia (27.8 months). Median times to launch were longer for the entire sample of 46 cancer medicines that obtained marketing authorization between 2000 and 2014. In the all-country model, medicines with shorter times to submission for reimbursement, local manufacturers headquarter (or local sales representative), and a Food and Drugs Administration priority review or a combination of expedited approval programs and medicines launched in Scotland and Sweden were associated with a higher hazard of launch. Longer times since EU-wide approval initially correlate with an increased hazard but as time further elapses they negatively affect the hazard of launch.Conclusions
Median times from marketing authorization to first use of cancer medicines were shorter for medicines launched between 2010 and 2014 versus sample-wide (2000–2014). In Estonia, more medicines than in the other countries were not yet launched at the end of the observation period. There was no correlation between Prescrire and European School of Medical Oncology Magnitude of Clinical Benefit Scale ratings of added clinical value and time to launch. 相似文献7.
Klein-Júnior CA Zander-Grande C Amaral R Stanislawczuk R Garcia EJ Baumhardt-Neto R Meier MM Loguercio AD Reis A 《Journal of dentistry》2008,36(8):618-625
OBJECTIVES: This study evaluated the effect of a warm or cold air-dry stream for solvent evaporation on the microtensile resin-dentin bond strength (muTBS), nanoleakage pattern (SEM), degree of conversion (DC) and solvent evaporation rates (SE) of an ethanol/water- (Adper Single Bond, [SB] 3MESPE) and an acetone-based (Prime & Bond 2.1, [PB] Dentsply), two-step etch-and-rinse adhesive system. MATERIALS AND METHODS: Adhesives were applied on demineralized dentin surfaces. For SE, a warm or cold air-dry stream (10 s) was applied prior to light-activation (10 s). Bonded sticks (0.8mm2) were tested in tension (0.5 mm/min). Two bonded sticks from each tooth were immersed in a 50% (w/v) solution of silver nitrate (24 h), photodeveloped (8 h) and analyzed by SEM. The DC and solvent evaporation rate of the adhesives were evaluated under FTIR and analytical balance, respectively. Data were analyzed by two-way ANOVA and Tukey test (alpha=0.05). RESULTS: Higher muTBS and lower nanoleakage were observed when the SE step was performed with warm air-dry stream. However, the DC of the adhesives was not altered by the use of a warm air-dry. CONCLUSIONS: The use of a warm air-dry stream seems to be a clinical tool to improve the bond strength and the quality of the hybrid layer (less nanoleakage infiltration), since it might reduce the number of pores within the adhesive layer. 相似文献
8.
Objectives
To evaluate the effect of the application method on the immediate and 3-year resin-dentine bond strength (μTBS) and nanoleakage (NL) for 3 one-step self-etch adhesives (Adper Prompt L-Pop; Clearfil S3 Bond and Xeno III).Methods
The occlusal enamel of 42 human molars were removed to expose a flat dentine surface. The adhesives were applied under inactive or active application. After light-curing (600 mW/cm2 for 10 s), composite buildups were constructed incrementally and sectioned to obtain bonded sticks (0.8 mm2) to be tested in tension immediately or after 3 years of water storage of water storage. For NL, 2 bonded sticks from each tooth at each time were coated with nail varnish, placed in silver nitrate and polished down with SiC paper. The μTBS data was submitted to a two-way repetead mesures ANOVA and Tukey's test for each adhesive (α = 0.05).Results
The active application showed higher immediate and 3-year μTBS than the inactive application (p < 0.05). An increase in the silver nitrate deposition was seen for all conditions after 3 years; however this was more pronounced for all materials under inactive application (p < 0.05).Conclusions
The active application improves the immediate bonding performance of the adhesive systems. Reductions of the bond strength were observed for all materials after 3 years, however reduced degradation rate was observed when the materials are applied actively in dentine. 相似文献9.
10.
Borges AL Costa AK Saavedra GS Komori PC Borges AB Rode SM 《Acta odontológica latinoamericana : AOL》2011,24(2):193-199
Coloring in drinks decreases the color stability of composite restorations, reducing their longevity. The purpose of this in vitro study was to evaluate the effect of immersion media on color stability of seven different composite resins (Solidex - Shofu, Resilab-Wilcos, Signum - Heraeus, Epricord - Tokuyama, Adoro - Ivoclar Vivadent, Admira - Voco and Sinfony - 3MESPE). Seven resin-based composite specimens were prepared using a cylindrical teflon mold 2 mm thick and 10 mm in diameter Fifteen specimens of each resin were light-cured according to manufacturers' instructions and randomized into 3 groups (n= 5) according to immersion media: coffee, cola beverage and water A digital spectrophotometer Easy Shade (VITA) was used to evaluate the color changes at baseline and 7 days after immersion in each solution. Specimens were stored in the different staining media for 24 h/day during one week. The color differences were analyzed by two-way ANOVA and Tukey 's test (p< 0.05). Color change was observed after one week of immersion and there were statistical differences in staining, composite and interaction factors. The least staining was observed in Admira (deltaE= 3.934+/-0.814) and Resilab (deltaE= 3.993+/-0.735), followed by Adoro (deltaE= 4.044+/-1.001), Epri-cord (deltaE= 4.049+/-1.234), Signum (deltaE= 4.260+/-1.785), Solidex (deltaE=5,122+/-0.534) and Sinfony (deltaE=5.126+/-0.838). All of the composites tested except Adoro were susceptible to staining by substances present in coffee and cola, when stored in beverage for seven days. The lowest deltaE means were obtained with Admira. 相似文献