全文获取类型
收费全文 | 16495篇 |
免费 | 873篇 |
国内免费 | 87篇 |
专业分类
耳鼻咽喉 | 217篇 |
儿科学 | 369篇 |
妇产科学 | 292篇 |
基础医学 | 2244篇 |
口腔科学 | 1578篇 |
临床医学 | 1150篇 |
内科学 | 3740篇 |
皮肤病学 | 340篇 |
神经病学 | 1627篇 |
特种医学 | 340篇 |
外科学 | 2064篇 |
综合类 | 59篇 |
一般理论 | 5篇 |
预防医学 | 1402篇 |
眼科学 | 301篇 |
药学 | 1023篇 |
中国医学 | 106篇 |
肿瘤学 | 598篇 |
出版年
2023年 | 148篇 |
2022年 | 367篇 |
2021年 | 620篇 |
2020年 | 415篇 |
2019年 | 514篇 |
2018年 | 664篇 |
2017年 | 424篇 |
2016年 | 487篇 |
2015年 | 560篇 |
2014年 | 723篇 |
2013年 | 869篇 |
2012年 | 1298篇 |
2011年 | 1557篇 |
2010年 | 757篇 |
2009年 | 611篇 |
2008年 | 1046篇 |
2007年 | 1022篇 |
2006年 | 889篇 |
2005年 | 771篇 |
2004年 | 696篇 |
2003年 | 571篇 |
2002年 | 518篇 |
2001年 | 275篇 |
2000年 | 212篇 |
1999年 | 195篇 |
1998年 | 99篇 |
1997年 | 58篇 |
1996年 | 64篇 |
1995年 | 59篇 |
1994年 | 38篇 |
1993年 | 43篇 |
1992年 | 74篇 |
1991年 | 71篇 |
1990年 | 79篇 |
1989年 | 69篇 |
1988年 | 49篇 |
1987年 | 49篇 |
1986年 | 44篇 |
1985年 | 51篇 |
1984年 | 35篇 |
1983年 | 23篇 |
1982年 | 19篇 |
1979年 | 23篇 |
1978年 | 24篇 |
1977年 | 16篇 |
1975年 | 17篇 |
1974年 | 19篇 |
1973年 | 25篇 |
1967年 | 17篇 |
1966年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Luísa Martins Miller Flvia Benetti Piccinin Ubele van der Velden Sabrina Carvalho Gomes 《Nutrients》2022,14(9)
Aim: This systematic review examined the additional effect of taking omega-3 supplements on periodontal therapy. Methods: The focused question was “What is the possible effect of omega-3 supplementation concomitant to non-surgical periodontal therapy on clinical periodontal parameters?” Databases Cochrane, Embase, Google Scholar, PubMed, and Web of Science (January-July 2021) were searched to identify appropriate studies. Randomized clinical trials (RCT) about non-surgical therapy with omega-3 supplementation, with at least 3 months of supplementation period were included. Cochrane risk of bias tool version 2 and Grading of Recommendations Assessment, Development, and Evaluation were used. Results: A total of 1556 studies were found, of which eight studies met the inclusion criteria. All eight studies evaluated periodontal probing depth and clinical attachment loss; plaque and gingival inflammation were evaluated in seven studies. High variety of omega-3 dosage, different study lengths, questionable results from periodontal therapy (including test and control groups), high risk of bias and moderate quality of evidence prevented a satisfactory conclusion regarding the benefits of omega-3 supplementation. The studies’ high heterogeneity avoided meta-analysis. Conclusion: Notwithstanding all limitations, the promising effects of omega-3 supplementation presented in two six-month studies encourage performing RCT with better-defined treatment protocols and greater methodological rigor. 相似文献
92.
Anja Lazi Miodrag Koci Neboja Trajkovi Cristian Popa Leonardo Alexandre Peyr-Tartaruga Johnny Padulo 《Nutrients》2022,14(9)
Caffeine supplementation has become increasingly popular among athletes. The benefits of caffeine include delaying the negative effects of fatigue, maintaining a high level of physical and mental performance, and improving certain abilities necessary for sport success. Given the complex nature of basketball, caffeine could be a legal, ergogenic stimulant substance, which will positively affect overall basketball performance. The purpose of this systematic review was to summarize evidence for the effect of acute caffeine ingestion on variables related to the basketball performance. Web of Science, PubMed, Scopus and ProQuest, MEDLINE, and ERIC databases were searched up to February 2021. Studies that measured the acute effect of caffeine on basketball performance were included and analyzed. Eight studies published between 2000 and 2021 were included in the analysis. Pre-exercise caffeine intake increased vertical jump height, running time at 10 and 20 m without the ball, overall basketball performance (number of body impacts, number of free throws, rebounds, and assists) during simulated games, and reduced the time required to perform a basketball-specific agility test. Equivocal results between caffeine and placebo groups were found for aerobic capacity, free throw and three-point accuracy, and dribbling speed. Pre-exercise caffeine ingestion did not affect RPE, but insomnia and urinary excretion were increased. The pre-exercise ingestion of 3 and 6 mg/kg caffeine was found to be effective in increasing several physical performance variables in basketball players during sport-specific testing and simulated matches. However, considering the intermittent nature and complexity of basketball, and individual differences between players, future studies are needed. 相似文献
93.
Dayne L. Filer Kate Hoffman Robert M. Sargis Leonardo Trasande Christopher D. Kassotis 《Environmental health perspectives》2022,130(5)
Background: Research suggests environmental contaminants can impact metabolic health; however, high costs prohibit in vivo screening of putative metabolic disruptors. High-throughput screening programs, such as ToxCast, hold promise to reduce testing gaps and prioritize higher-order (in vivo) testing.Objectives: We sought to a) examine the concordance of in vitro testing in 3T3-L1 cells to a targeted literature review for 38 semivolatile environmental chemicals, and b) assess the predictive utility of various expert models using ToxCast data against the set of 38 reference chemicals.Methods: Using a set of 38 chemicals with previously published results in 3T3-L1 cells, we performed a metabolism-targeted literature review to determine consensus activity determinations. To assess ToxCast predictive utility, we used two published ToxPi models: a) the 8-Slice model published by Janesick et al. (2016) and b) the 5-Slice model published by Auerbach et al. (2016). We examined the performance of the two models against the Janesick in vitro results and our own 38-chemical reference set. We further evaluated the predictive performance of various modifications to these models using cytotoxicity filtering approaches and validated our best-performing model with new chemical testing in 3T3-L1 cells.Results: The literature review revealed relevant publications for 30 out of the 38 chemicals (the remaining 8 chemicals were only examined in our previous 3T3-L1 testing). We observed a balanced accuracy (average of sensitivity and specificity) of 0.86 comparing our previous in vitro results to the literature-derived calls. ToxPi models provided balanced accuracies ranging from 0.55 to 0.88, depending on the model specifications and reference set. Validation chemical testing correctly predicted 29 of 30 chemicals as per 3T3-L1 testing, suggesting good adipogenic prediction performance for our best adapted model.Discussion: Using the most recent ToxCast data and an updated ToxPi model, we found ToxCast performed similarly to that of our own 3T3-L1 testing in predicting consensus calls. Furthermore, we provide the full ranked list of largely untested chemicals with ToxPi scores that predict adipogenic activity and that require further investigation. https://doi.org/10.1289/EHP6779 相似文献
94.
Locatelli C Carvalho DR Mascarello A de Cordova CA Yunes RA Nunes RJ Pilati C Creczynski-Pasa TB 《Investigational new drugs》2012,30(3):870-879
Gallates with eight or more carbon atoms in the lateral chain show potent anticancer activity against various cell lines. However, studies regarding the in vivo antimelanoma activity of tetradecyl gallate (C14) have not yet been reported. In this study an evaluation of the ability of C14 to inhibit metastasis, using lung metastases as a model, was carried out. The experimental mouse melanoma model was established by intravenous injection of metastatic B16F10 melanoma cells. The systemic toxicity of C14 was evaluated in vivo by monitoring the weight, survival, biochemical and hematological parameters, and through histological analysis. It was observed that C14 decreased lung metastasis in vivo by 80% and increased the survival rate of the animals without toxic effects. Additionally, C14 induced cytotoxic effects on B16F10 cells, inhibited the inter-cellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) expression, and significantly decreased cell adhesion. These results reveal that C14 has potent antimetastatic ability and is a good candidate for further study as a potential therapeutic agent for tumor metastases. 相似文献
95.
Patrizio Tatti Leonardo Masselli Patrizia Di Mauro Giuseppe Pipicelli Annalisa Pipicelli Annabel Barber 《Mediterranean journal of nutrition and metabolism》2012,5(1):67-69
We evaluated if a nutritional supplement containing arginine, glutamine, β-hydroxy-β-methyl butyrate commonly used to improve the healing of diabetic foot ulcers had any effect on the kidney function in the diabetic patients. We hypothesized that the action on the skin may be nonspecific and that the supplement might also act on other structural elements of the kidney. We compared the evolution of the blood creatinine and of the overnight albumin excretion in 16 diabetic subjects with mild to moderate nephropathy 6 months prior to and during the 6 months of treatment. The creatinine level remained stable during the treatment, while microalbuminuria decreased to nearly 50% of the initial value (p < 0.000). 相似文献
96.
97.
Earl R. Burrell Heather A. Pines Edward Robbie Leonardo Coleman Ryan D. Murphy Kristen L. Hess Peter Anton Pamina M. Gorbach 《AIDS and behavior》2012,16(7):1816-1820
Mobile phone social networking applications such as GRINDR are potential tools for recruitment of men who have sex with men (MSM) for HIV prevention research. Demographics and sexual risk behaviors of men recruited through GRINDR and through traditional media were compared. GRINDR participants were younger (mean age 31 vs. 42, p?<?0.0001), more White identified (44 vs. 30?%, p?<?0.01), and had more sex partners in the previous 14 days (1.88 vs. 1.10, p?<?0.05) than other recruits. Email responses were less successful for enrollment than phone calls (5 vs. 50?%). This approach resulted in successful recruitment of younger and more educated, White identified MSM. 相似文献
98.
99.
Guenael Freire de Souza Darlene Carvalho William Pedrosa Jacqueline Franck Renaud Piarroux 《The Brazilian journal of infectious diseases》2012,16(6):574-576
There are often discrepancies when using different methods to measure anti-Toxoplasma gondii IgG levels in patient samples. The diagnostic performance of a chemiluminescent immunoassay (CLIA) and an enzyme-linked fluorescent assay (ELFA) used as confirmatory tests for samples identified as positive or equivocal by an electrochemiluminescent immunoassay (ECLIA) were examined. Cut-off values were those stated by the manufacturer, and Western blot was used to confirm the results of all methods. All samples identified as positive by ECLIA (n = 93) were confirmed as positive by Western blot, as were 14 of the 28 samples identified as equivocal. When these 121 samples were retested, the sensitivities of CLIA and ELFA were 64.4% and 73.8%, respectively. Both methods exhibited a specificity of 100%. This study confirms that the results obtained from the different immunoassays are not comparable, and neither CLIA nor ELFA should be used to confirm ECLIA results, which should instead be confirmed by methods such as Western blot or Sabin-Feldman dye test. 相似文献
100.