全文获取类型
收费全文 | 20045篇 |
免费 | 1781篇 |
国内免费 | 658篇 |
专业分类
耳鼻咽喉 | 228篇 |
儿科学 | 394篇 |
妇产科学 | 456篇 |
基础医学 | 2482篇 |
口腔科学 | 335篇 |
临床医学 | 1466篇 |
内科学 | 4314篇 |
皮肤病学 | 349篇 |
神经病学 | 1071篇 |
特种医学 | 334篇 |
外国民族医学 | 2篇 |
外科学 | 2766篇 |
综合类 | 2455篇 |
一般理论 | 1篇 |
预防医学 | 1162篇 |
眼科学 | 229篇 |
药学 | 2173篇 |
4篇 | |
中国医学 | 726篇 |
肿瘤学 | 1537篇 |
出版年
2024年 | 26篇 |
2023年 | 323篇 |
2022年 | 476篇 |
2021年 | 1466篇 |
2020年 | 1015篇 |
2019年 | 1388篇 |
2018年 | 1493篇 |
2017年 | 904篇 |
2016年 | 670篇 |
2015年 | 812篇 |
2014年 | 1389篇 |
2013年 | 1249篇 |
2012年 | 1073篇 |
2011年 | 1218篇 |
2010年 | 985篇 |
2009年 | 821篇 |
2008年 | 833篇 |
2007年 | 872篇 |
2006年 | 677篇 |
2005年 | 573篇 |
2004年 | 523篇 |
2003年 | 508篇 |
2002年 | 303篇 |
2001年 | 224篇 |
2000年 | 212篇 |
1999年 | 220篇 |
1998年 | 322篇 |
1997年 | 253篇 |
1996年 | 178篇 |
1995年 | 143篇 |
1994年 | 127篇 |
1993年 | 96篇 |
1992年 | 92篇 |
1991年 | 78篇 |
1990年 | 54篇 |
1989年 | 57篇 |
1988年 | 61篇 |
1987年 | 36篇 |
1986年 | 44篇 |
1985年 | 79篇 |
1984年 | 93篇 |
1983年 | 59篇 |
1982年 | 88篇 |
1981年 | 64篇 |
1980年 | 71篇 |
1979年 | 64篇 |
1978年 | 43篇 |
1977年 | 40篇 |
1975年 | 25篇 |
1974年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
《Clinical Lymphoma, Myeloma & Leukemia》2020,20(8):e461-e467
IntroductionVon Willebrand factor (vWF) cleaving protease ADAMTS-13 has a key role for maintaining normal size of vWF. A deficiency or dysfunction of vWF cleaving protease is associated with ultra large vWF multimers and thrombotic microangiopathy. Patients with cancers have reduced levels of vWF cleaving protease. In this pilot study, we have evaluated whether or not deficiencies of ADAMTS-13 were present in myelodysplastic syndromes (MDS). Moreover, we assessed if a reduction in basal levels of ADAMTS-13 may play a role in the prognosis of MDS.Patients and MethodsWe measured and compared the levels of vWF cleaving protease ADAMTS-13 in 100 patients with MDS and 35 healthy controls. Patients were divided into 2 groups according to the International Prognostic Scoring System: group I consisting of 44 patients with low-risk MDS and group II of 56 patients with high-risk MDS. Patients with high-risk and low-risk MDS presented significantly lower levels of ADAMTS-13 than controls (P < .001 and P = .0177, respectively). High-risk patients had significantly lower levels of ADAMTS-13 when compared with the low-risk group (P < .001).ResultsWe found that reduced levels of ADAMTS-13 have a relationship with overall survival (P < .001). Statistical analysis showed that ADAMTS-13 correlates with cytogenetics (P < .001) and a tendency of slight correlation with platelet count and basal levels of ADAMTS-13 (R, 0.35; P value, 0.001). Moreover, we found that levels of ADAMTS-13 have correlation with response to treatment (P < .001).ConclusionsADAMTS-13 in MDS might represent a surrogate marker of prognosis, response to therapy, or disease progression. Further studies are needed. 相似文献
32.
Samira Marín-Romero Teresa Elías-Hernández María Isabel Asensio-Cruz Rocío Ortega-Rivera Raquel Morillo-Guerrero Javier Toral Emilio Montero Verónica Sánchez Elena Arellano José María Sánchez-Díaz Macarena Real-Domínguez Remedios Otero-Candelera Luis Jara-Palomares 《Archivos de bronconeumología》2019,55(12):619-626
IntroductionScales for predicting venous thromboembolism (VTE) recurrence are useful for deciding the duration of the anticoagulant treatment. Although there are several scales, the most appropriate for our setting has not been identified. For this reason, we aimed to validate the DASH prediction score and the Vienna nomogram at 12 months.MethodsThis was a retrospective study of unselected consecutive VTE patients seen between 2006 and 2014. We compared the ability of the DASH score and the Vienna nomogram to predict recurrences of VTE. The validation was performed by stratifying patients as low-risk or high-risk, according to each scale (discrimination) and comparing the observed recurrence with the expected rate (calibration).ResultsOf 353 patients evaluated, 195 were analyzed, with an average age of 53.5 ± 19 years. There were 21 recurrences in 1 year (10.8%, 95% CI: 6.8%-16%). According to the DASH score, 42% were classified as low risk, and the rate of VTE recurrence in this group was 4.9% (95% CI: 1.3%-12%) vs. the high-risk group that was 15% (95% CI: 9%-23%) (p <.05). According to the Vienna nomogram, 30% were classified as low risk, and the rate of VTE recurrence in the low risk group vs. the high risk group was 4.2% (95% CI:0.5%-14%) vs. 16.2% (95% CI: 9.9%-24.4%) (p <.05).ConclusionsOur study validates the DASH score and the Vienna nomogram in our population. The DASH prediction score may be the most advisable, both because of its simplicity and its ability to identify more low-risk patients than the Vienna nomogram (42% vs. 30%). 相似文献
33.
34.
Hepatitis C is a major public health problem worldwide. This disease is caused by the hepatitis C virus, which is characterised by its genetic diversity. The infection is usually asymptomatic. However, between 60% and 80% of HCV-infected individuals will progress to chronic hepatitis, 20% to liver cirrhosis in the medium-to long-term and, each year, between 1% and 4% of these patients with cirrhosis will develop hepatocellular carcinoma (HCC). A Spanish consensus document has recently been drafted to diagnose hepatitis C in a single step, consisting of active investigation (antibodies and viremia) in a single sample, which according to the experts, would reduce the time to access treatment and avoid tracking losses. To definitively change the hepatitis C treatment paradigm, direct-acting antiviral drugs (DAAs) have been approved, whose development has been based on achieving cure rates close to 100% regardless of the genotype of the virus, ie, pangenotypes, with good tolerance and bioavailability. These drugs have constituted a real therapeutic revolution. Supplement information: This article is part of a supplement entitled «SEIMC External Quality Control Programme. Year 2016», which is sponsored by Roche, Vircell Microbiologists, Abbott Molecular and Francisco Soria Melguizo, S.A.© 2019 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosasy Microbiología Clínica. All rights reserved. 相似文献
35.
《Journal of pharmaceutical sciences》2019,108(10):3425-3433
This study aimed at evaluating how encapsulation in a regular nanocarrier (NC) (providing extended circulation time) or in a brain-targeting NC (providing prolonged circulation time and increased brain uptake) may influence the therapeutic index compared with the unformulated drug and to explore the key parameters affecting therapeutic performance using a model-based approach. Pharmacokinetic (PK) models were built with chosen PK parameters. For a scenario where central effect depends on area under the unbound brain concentration curve and peripheral toxicity relates to peak unbound plasma concentration, dose-effect and drug-side effect curves were constructed, and the therapeutic index was evaluated. Regular NC improved the therapeutic index compared with the unformulated drug due to reduced peripheral toxicity, while brain-targeting NC enhanced the therapeutic index by lowering peripheral toxicity and increasing central effect. Decreasing drug release rate or systemic clearance of NC with drug still encapsulated could increase the therapeutic index. Also, a drug with shorter half-life would therapeutically benefit more from a NC encapsulation. This work provides insights into how a NC for brain delivery should be optimized to maximize the therapeutic performance and is helpful to predict if and to what extent a drug with certain PK properties would obtain therapeutic benefit from nanoencapsulation. 相似文献
36.
目的探讨负载 IL-4 和 BMP-2 的氧化石墨烯(graphene oxide,GO)-羧甲基壳聚糖(carboxymethyl chitosan,CMC)凝胶诱导巨噬细胞 M2 型分化及对 BMSCs 成骨分化的影响。方法取 CMC、GO 制备混合溶液后,分别添加 PBS、IL-4、BMP-2 或 IL-4+BMP-2,在交联剂作用下制备单纯或负载不同因子的 GO-CMC 凝胶支架;取单纯 GO-CMC 凝胶表征观测,包括大体、扫描电镜及傅里叶变换红外吸收光谱仪(Fourier transform infrared spectroscopy,FTIR)检测,以单纯 CMC 凝胶作为对照;取负载不同因子的 GO-CMC 凝胶行体外缓释实验。取 4~5 周龄 SPF 级 SD 雌性大鼠分离培养巨噬细胞,分别与单纯以及负载不同因子的 GO-CMC 凝胶培养,24 h 后行 CD206 免疫荧光检测巨噬细胞分化情况;取第 3 代大鼠 BMSCs 分别与单纯以及负载不同因子的 GO-CMC 凝胶成骨诱导培养,10 d 后行 ALP 染色观测早期成骨,21 d 行茜素红染色观测晚期成骨。结果大体观察 GO-CMC 凝胶呈棕色、半透明状;扫描电镜观察示,GO-CMC 凝胶孔径及孔壁厚度与单纯 CMC 凝胶相似,但内壁粗糙度增加;FTIR 检测显示 CMC 发生聚合形成凝胶。体外缓释实验示 3 种负载不同因子的 GO-CMC 凝胶缓释性能相似,均呈线性缓慢释放因子。CD206 免疫荧光检测示 GO-CMC 凝胶可诱导巨噬细胞 M2 型分化,ALP 及茜素红染色示 GO-CMC 凝胶可诱导 BMSCs 成骨分化;其中负载 IL-4+BMP-2 的 GO-CMC 凝胶作用最显著(P<0.05)。 结论负载 IL-4 和 BMP-2 的 GO-CMC 凝胶可诱导巨噬细胞 M2 型分化,增强 BMSCs 成骨分化能力,为后期骨缺损修复及骨免疫调节研究提供了新的策略。 相似文献
37.
《Revista espa?ola de cardiología》2019,72(12):1012-1019
Introduction and objectivesThe Spanish Society of Cardiology/Spanish Heart Foundation (SEC/FEC) annually awards grants for cardiovascular research projects. Our objective was to analyze the trend in these investments and their resulting scientific production from 2007 to 2012.MethodsA search of the publications funded by the SEC/FEC was carried out, according to the following inclusion criteria: publication in a journal indexed in MEDLINE or EMBASE, publication date after the grant, authorship by the principal investigator of the grant, and acknowledgment of SEC/FEC funding. The impact factor and subsequent citations of the articles were analyzed (Web of Science).ResultsA total of 235 grants were awarded (39/y) with an allocation of €3 854 300 (€642 383/y), 37% of them to women. In all, 122 publications resulted from 88 research projects (37%) funded by the SEC/FEC. Up to October 2017, these publications had received 2258 citations in subsequent studies in the Web of Science, with a mean of 18.5 and a median of 8 citations/study.ConclusionsDespite the economic crisis, the mean number and size of the grants awarded by the SEC/FEC increased in the period analyzed. Grants were awarded on an equal opportunity basis to men and women. The bibliometric impact of the funded projects is acceptable, although efforts should be made to improve it. 相似文献
38.
Objective
The aim of this paper is to study the opportunity costs (OC) that are involved in being a caregiver and to compare them with the direct costs assumed by the State and the families. We evaluate direct cost (those that imply a payment-out-of-pocket) and indirect cost (those that imply a dedication in time). We hypothesized that costs increase with the severity of the dementia, with the educational level and active occupational situation of caregiver. They are greater if the caregiver is male, but if the patient and caregiver cohabit they are reduced.Method
778 surveys were analyzed. Data was collected using a questionnaire specifically designed for the purpose, with the collaboration of Alzheimer's Diseases Associations in Andalusia (Spain). For the indirect cost, we used the reveal preferences method. For the comparison between groups an ANOVA and a MANOVA was done.Results
The hypotheses were confirmed. The OC exponentially increases with severity. More than 55% of costs are assumed by families. Occupied people have higher educational level and incomes and contract more external support. Costs are significantly higher for male caregivers. Cohabiting reduces all kinds of costs.Conclusions
The relationship between educational level and employment situation lead to think that if these variables are greater more people will seek professional support. Cultural reasons still maintain women as main caregivers for all educational levels. The existence of these informal caregivers as the main care providers is a saving for the State, and a brake for the development of professional supply. 相似文献39.
Objective
To explore from a gender perspective the association with subjective health of the interaction between education and household arrangements within the framework of social determinants of health placed at the micro and mezzo levels.Methods
The data comes from the Spanish sample of the European Union Statistics on Income and Living Conditions for 2014. Independent logistic regression models for men and women were run to analyze the association with subjective health of the interaction between education and household arrangements. An additive model was run to assess possible advantages over the interaction approach.Results
The interaction models show a lower or even no significant effect on health of household arrangements usually negatively associated with health among individuals with high education, displaying specific patterns according to sex.Conclusions
Health profiles of women and men are more precisely drawn if both social determinants of health are combined. Among the women, the important role was confirmed of both social determinants of health in understanding their health inequalities. Among the men, mainly those with low educational achievement, the interaction revealed that the household was a more meaningful social determinant of health. This could enable the definition of more efficient public policies to reduce health and gender inequalities. 相似文献40.
目的对膝关节前外侧韧带(anterolateral ligament,ALL)的研究进展进行综述,为临床诊治提供参考。方法广泛查阅近年来国内外有关 ALL 损伤诊断及治疗的文献,总结膝关节 ALL 解剖形态、生物力学以及 ALL 损伤机制、治疗现状。结果膝关节 ALL 具有限制胫骨内旋及前移作用,影响膝关节轴移。ALL 损伤后可结合患者体征和 MRI 检查诊断。膝关节 ALL 手术指征尚未统一,但多数学者倾向于对需进行前交叉韧带(anterior cruciate ligament,ACL)重建或翻修且伴有高度轴移试验阳性的患者进行 ALL 重建。目前 ALL 重建方式较多,但尚无最佳治疗术式。此外,由于缺乏高质量的术后长期随访研究,远期临床疗效仍不明确。结论ALL 在维持膝关节稳定性方面具有一定作用,但 ALL 重建技术及临床疗效仍待进一步研究。 相似文献