全文获取类型
收费全文 | 3202篇 |
免费 | 258篇 |
国内免费 | 82篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 221篇 |
妇产科学 | 68篇 |
基础医学 | 392篇 |
口腔科学 | 65篇 |
临床医学 | 399篇 |
内科学 | 669篇 |
皮肤病学 | 76篇 |
神经病学 | 234篇 |
特种医学 | 428篇 |
外科学 | 394篇 |
综合类 | 62篇 |
预防医学 | 203篇 |
眼科学 | 26篇 |
药学 | 149篇 |
2篇 | |
中国医学 | 1篇 |
肿瘤学 | 151篇 |
出版年
2021年 | 12篇 |
2020年 | 19篇 |
2019年 | 22篇 |
2018年 | 42篇 |
2017年 | 26篇 |
2016年 | 31篇 |
2015年 | 46篇 |
2014年 | 61篇 |
2013年 | 79篇 |
2012年 | 73篇 |
2011年 | 82篇 |
2010年 | 118篇 |
2009年 | 112篇 |
2008年 | 105篇 |
2007年 | 162篇 |
2006年 | 105篇 |
2005年 | 124篇 |
2004年 | 69篇 |
2003年 | 71篇 |
2002年 | 77篇 |
2001年 | 81篇 |
2000年 | 91篇 |
1999年 | 90篇 |
1998年 | 148篇 |
1997年 | 170篇 |
1996年 | 142篇 |
1995年 | 122篇 |
1994年 | 132篇 |
1993年 | 107篇 |
1992年 | 64篇 |
1991年 | 73篇 |
1990年 | 80篇 |
1989年 | 83篇 |
1988年 | 84篇 |
1987年 | 78篇 |
1986年 | 74篇 |
1985年 | 66篇 |
1984年 | 39篇 |
1983年 | 29篇 |
1982年 | 33篇 |
1981年 | 36篇 |
1980年 | 40篇 |
1979年 | 22篇 |
1978年 | 21篇 |
1977年 | 27篇 |
1976年 | 34篇 |
1975年 | 29篇 |
1974年 | 11篇 |
1972年 | 11篇 |
1970年 | 12篇 |
排序方式: 共有3542条查询结果,搜索用时 15 毫秒
1.
Catherine Bland Kathryn V. Dalrymple Sara L. White Amanda Moore Lucilla Poston Angela C. Flynn 《Maternal & child nutrition》2020,16(2)
The importance of diet during pregnancy is critically important for the short‐ and long‐term health of both mother and child. The number of apps targeting pregnant women is rapidly increasing, yet the nutritional content of these tools remains largely unexplored. This review aimed to evaluate the coverage and content of nutrition information in smartphone apps available to U.K. pregnant women. Keyword searches were conducted in iTunes and Google Play stores in November 2018. Candidate apps were included if they targeted pregnant women, provided pregnancy‐specific nutritional information, had a user rating of at least 4+ based on at least 20 ratings, and were available in English. Nutritional content was assessed for accuracy against U.K. recommendations. Behaviour change techniques (BCTs) were also evaluated. Twenty‐nine apps were included, seven of which originated in the United Kingdom. There was a large variability in the quality of smartphone app nutritional information. The accuracy of nutrition information varied, and several apps conveyed inappropriate information for pregnancy. On average, 10 BCTs were identified per app (range 2–15). Overall, smartphone apps do not consistently provide accurate and useful nutritional information to pregnant women. This study highlights the need for the integration of evidence‐based nutritional information during app development and for increased regulatory oversight. App developers should also make it clear that nutritional content is intended for a specific geographical region or population or modify for the intended audience. These are important considerations for the design of future apps, which are increasingly used to complement existing maternity services. 相似文献
2.
3.
Brendan Keane Nicholas S. Bland Natasha Matthews Timothy J. Carroll Guy Wallis 《The European journal of neuroscience》2020,51(7):1697-1710
Recent history influences subsequent perception, decision‐making and motor behaviours. In this article, we address a discrepancy in the effects of recent sensory history on the perceived timing of auditory and visual stimuli. In the synchrony judgement (SJ) task, similar timing relationships in consecutive trials seem more synchronous (i.e. less like the repeated temporal order). This effect is known as rapid recalibration and is consistent with a negative perceptual aftereffect. Interestingly, the opposite is found in the temporal order judgement (TOJ) task (positive rapid recalibration). We aimed to determine whether a simple bias to repeat judgements on consecutive trials (choice‐repetition bias) could account for the discrepant results in these tasks. Preliminary simulations and analyses indicated that a choice‐repetition bias could produce apparently positive rapid recalibration in the TOJ and not the SJ task. Our first experiment revealed no evidence of rapid recalibration of TOJs, but negative rapid recalibration of associated confidence. This suggests that timing perception was rapidly recalibrated, but that the negative recalibration effect was obfuscated by a positive bias effect. In our second experiment, we experimentally mitigated the choice‐repetition bias effect and found negative rapid recalibration of TOJs. We therefore conclude that timing perception is negatively rapidly recalibrated, and this is observed consistently across timing tasks. These results contribute to a growing body of evidence that indicates multisensory perception is constantly undergoing recalibration, such that perceptual synchrony is maintained. This work also demonstrates that participants’ task responses reflect judgements that are contaminated by independent biases of perception and decision‐making. 相似文献
4.
5.
Aetiological factors for oral manifestations of HIV 总被引:2,自引:0,他引:2
GD Palmer PG Robinson SJ Challacombe W Birnbaum D Croser PL Erridge T Hodgson D Lewis A McLaren JM Zakrzewska 《Oral diseases》1996,2(3):193-197
OBJECTIVES: Describe the oral diseases in HIV-infected individuals in London, UK and identify social and medical factors related to the presence of specific oral diseases.
DESIGN: Cross-sectional analytic study.
SETTING: Dental clinics.
SUBJECTS: Consecutive sample of 456 patients with HIV infection.
METHODS: Social and medical history and clinical examinations. Univariate and logistic regression analysis.
OUTCOMES: Presence of HIV-associated oral disease.
RESULTS: 80% of patients with AIDS and 50% of patients with HIV had a specific oral disease. The most common diseases were hairy leukoplakia (30%), erythematous candidiasis (24%), pseudomembranous candidiasis (14%), angular chielitis (6%), necrotising periodontal disease (8%) and non-recurrent ulceration (6%).
CONCLUSIONS: The presence of erythematous candidiasis was not related to advanced HIV disease. Pseudomembranous candidiasis, hairy leukoplakia and mucosal ulceration were significantly associated with advanced HIV disease. Smoking was also identified as a strong aetiological factor in oral diseases. Longitudinal studies are required to further explore the prognostic significance of oral diseases in HIV infection. 相似文献
DESIGN: Cross-sectional analytic study.
SETTING: Dental clinics.
SUBJECTS: Consecutive sample of 456 patients with HIV infection.
METHODS: Social and medical history and clinical examinations. Univariate and logistic regression analysis.
OUTCOMES: Presence of HIV-associated oral disease.
RESULTS: 80% of patients with AIDS and 50% of patients with HIV had a specific oral disease. The most common diseases were hairy leukoplakia (30%), erythematous candidiasis (24%), pseudomembranous candidiasis (14%), angular chielitis (6%), necrotising periodontal disease (8%) and non-recurrent ulceration (6%).
CONCLUSIONS: The presence of erythematous candidiasis was not related to advanced HIV disease. Pseudomembranous candidiasis, hairy leukoplakia and mucosal ulceration were significantly associated with advanced HIV disease. Smoking was also identified as a strong aetiological factor in oral diseases. Longitudinal studies are required to further explore the prognostic significance of oral diseases in HIV infection. 相似文献
6.
Minocycline HCl microspheres reduce red-complex bacteria in periodontal disease therapy 总被引:1,自引:0,他引:1
Goodson JM Gunsolley JC Grossi SG Bland PS Otomo-Corgel J Doherty F Comiskey J 《Journal of periodontology》2007,78(8):1568-1579
BACKGROUND: The objective of this trial was to measure the antimicrobial effects of a minocycline HCl microsphere (MM) local drug-delivery system when used as an adjunct to scaling and root planing (SRP). DNA probe analysis for 40 bacteria was used to evaluate the oral bacteria of 127 subjects with moderate to advanced chronic periodontitis. METHODS: Subjects were randomly assigned to either SRP alone (N = 65) or MM + SRP (N = 62). The primary endpoints of this study were changes in numbers and proportions of the red-complex bacteria (RCB) and the sum of Porphyromonas gingivalis, Tannerella forsythia (formally T. forsythensis), and Treponema denticola relative to 40 oral bacteria at each test site from baseline to day 30. Numbers of RCB from the five test sites were averaged to provide a value for each subject. RESULTS: MM + SRP reduced the proportion of RCB by 6.49% and the numbers by 9.4 x 10(5). The reduction in RCB proportions and numbers by SRP alone (5.03% and 5.1 x 10(5), respectively) was significantly less. In addition, MM + SRP reduced probing depth by 1.38 mm (compared to 1.01 mm by SRP alone), bleeding on probing was reduced by 25.2% (compared to 13.8% by SRP alone), and a clinical attachment level gain of 1.16 mm (compared to 0.80 mm by SRP alone) was achieved. CONCLUSION: These observations support the hypothesis that RCBs are responsible for periodontal disease and that local antimicrobial therapy using MM + SRP effectively reduces numbers of RCBs and their proportions to a greater extent than SRP alone. 相似文献
7.
Background: The use of ozone therapy in the treatment of dental caries is equivocal. The aim of this study was to use an in vitro model to determine the effects of prior ozone application to dentine on biofilm formation and to measure any associated reduction in bacteria viability. Methods: Twenty dentine discs were bonded to the bases of 5 mL polycarbonate screw top vials. Ten dentine discs were infused with ozone for 40 seconds, 10 samples remained untreated as a control. The vials were filled with nutrient medium, sterilized and placed into the outflow from a continuous chemostat culture of Streptococcus mutans and Lactobacillus acidophilus for four weeks. At the conclusion of the experiment bacterial growth was monitored by taking optical density readings of the growth medium in each vial and the outer surface of the dentine specimens were examined by scanning electron microscopy as shown by SEM analysis. Results: Ozone infusion prevented biofilm formation on all the treated samples while there was substantial biofilm present on the control specimens. While the average optical density of the control specimens was almost twice that of the ozone infused dentine (0.710 for the control with a SD of 0.288 and 0.446 for the ozonated samples with a SD of 0.371), the results were not significant (p > 0.05). Conclusions: This preliminary study has shown that the infusion of ozone into non‐carious dentine prevented biofilm formation in vitro from S. mutans and L. acidophilus over a four‐week period. The possibility exists that ozone treatment may alter the surface wettability of dentine through reaction with organic constituents. 相似文献
8.
GT Terézhalmy AR Biesbrock PA Walters JM Grender RD Bartizek 《International journal of dental hygiene》2008,6(4):321-327
Abstract: Aim: To compare plaque removal efficacy of Oral‐B CrossAction (CA) used for 1 min with an American Dental Association (ADA) manual toothbrush used for 2 or 5 min in an examiner‐blind, three‐treatment, six‐period crossover study. Materials and methods: After refraining from all oral hygiene procedures for 23–25 h, subjects were randomly assigned to one of nine possible six‐period (visit) treatment sequences. Plaque was assessed at baseline (Rustogi Modified Navy Plaque Index). Post‐brushing scores were recorded after brushing with a marketed dentifrice and the assigned toothbrush for the specified duration. The same procedure was followed at each of six subsequent visits. Clinical measurements were carried out by the same examiner. Results: Forty subjects completed the study. All three treatments effectively removed plaque from the whole mouth, along the gingival margin and from approximal surfaces. Whole mouth and gingival margin plaque removal scores with CA for 1 min did not differ significantly from scores with the ADA toothbrush used for 2 min. The ADA brush used for 5 min showed significantly greater whole mouth (P < 0.001) and gingival margin (P < 0.001) plaque reduction than the two other treatments. Approximal plaque removal scores did not differ between the three treatments. Conclusions: Efficient plaque removal can be achieved after 1 min of brushing with CA. The amount of plaque removed did not differ significantly from that achieved with the ADA brush after 2 min of brushing. Greater whole mouth and gingival margin plaque removal scores were seen with the ADA brush after 5 min. 相似文献
9.
JM Palefsky M-E Penaranda LT Pierik LA Lagenaur LA MacPhail D Greenspan JS Greenspan 《Oral diseases》1997,3(Z1):S171-S176
Hairy leukoplakia (HL) is a lesion found on the side of the tongue of immunocompromised individuals, including those with human immunodeficiency virus (HIV) infection. The lesion has unique histopathologic features and is characterised by high-level Epstein-Barr virus (EBV) replication, multiple EBV strains, and extensive inter-and intra-strain recombination. Expression of EBV genes spanning the entire viral life cycle from latency-associated genes to late, replicative genes has been detected in the lesion. HL thus provides a unique opportunity to study EBV expression in oral epithelium, and to study expression of novel EBV genes. We therefore constructed a cDNA library from an HL biopsy and detected expression of two genes not previously described in vivo: BMRF-2 and BDLF-3. Sequence analysis of the cDNAs revealed few amino acid changes from the B95-8 sequence. Expression of both genes was localized to the lower prickle cell layer of the tongue epithelium. BMRF-2 protein expression was primarily detected in the cell nuclei of the upper prickle cell layer. BDLF-3 protein expression was observed in the perinuclear space and Golgi compartment. The function of these proteins is currently under investigation. 相似文献
10.