全文获取类型
收费全文 | 13003篇 |
免费 | 596篇 |
国内免费 | 79篇 |
专业分类
耳鼻咽喉 | 178篇 |
儿科学 | 253篇 |
妇产科学 | 262篇 |
基础医学 | 1563篇 |
口腔科学 | 707篇 |
临床医学 | 1020篇 |
内科学 | 3174篇 |
皮肤病学 | 230篇 |
神经病学 | 1081篇 |
特种医学 | 282篇 |
外科学 | 2091篇 |
综合类 | 68篇 |
一般理论 | 6篇 |
预防医学 | 886篇 |
眼科学 | 258篇 |
药学 | 746篇 |
中国医学 | 48篇 |
肿瘤学 | 825篇 |
出版年
2024年 | 13篇 |
2023年 | 123篇 |
2022年 | 255篇 |
2021年 | 482篇 |
2020年 | 278篇 |
2019年 | 379篇 |
2018年 | 446篇 |
2017年 | 324篇 |
2016年 | 321篇 |
2015年 | 383篇 |
2014年 | 564篇 |
2013年 | 691篇 |
2012年 | 1128篇 |
2011年 | 1118篇 |
2010年 | 624篇 |
2009年 | 559篇 |
2008年 | 913篇 |
2007年 | 879篇 |
2006年 | 793篇 |
2005年 | 749篇 |
2004年 | 647篇 |
2003年 | 545篇 |
2002年 | 523篇 |
2001年 | 73篇 |
2000年 | 63篇 |
1999年 | 77篇 |
1998年 | 107篇 |
1997年 | 68篇 |
1996年 | 63篇 |
1995年 | 59篇 |
1994年 | 50篇 |
1993年 | 41篇 |
1992年 | 36篇 |
1991年 | 28篇 |
1990年 | 19篇 |
1989年 | 17篇 |
1988年 | 15篇 |
1987年 | 20篇 |
1986年 | 25篇 |
1985年 | 18篇 |
1984年 | 15篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 17篇 |
1980年 | 18篇 |
1979年 | 12篇 |
1977年 | 11篇 |
1975年 | 11篇 |
1974年 | 10篇 |
1969年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Agustín Julin-Jimnez Rafael Rubio-Díaz Juan Gonzlez del Castillo Francisco Javier Candel Gonzlez en nombre del grupo INFURG-SEMES 《Rev Esp Quimioter》2022,35(4):344
La atención de pacientes con sospecha de un proceso infeccioso en los servicios de urgencias hospitalarios(SUH) se ha incrementado en la última década hasta suponer alrededor del 15-20% de todas las atenciones diarias. En la valoración inicial de estos enfermos se toman muestras para los distintos estudios microbiológicos en un 45% de los casos, donde predomina la obtención de hemocultivos (HC), en el 14,6% de todos ellos. La rentabilidad diagnóstica de estos HC es muy variable (2-20%). Los focos o procesos infecciosos más frecuentes sospechados o confirmados de las bacteriemias verdaderas(BV) en los SUH son la infección del tracto urinario (45%) y la infección respiratoria (25%). Por todo ello, la sospecha y confirmación de la BV tiene un relevante significado diagnóstico, pronóstico y obliga a cambiar algunas de las decisiones más importantes a tomar en el SUH. Entre otras, indicar el alta o ingreso, extraer HC y administrar el antimicrobiano adecuado y precoz. La intención de esta revisión es poner de manifiesto las evidencias científicas publicadas en los últimos cinco años, aclarar las controversias existentes actuales y comparar la capacidad para predecir bacteriemia de los últimos modelos predictivos publicados desde el año 2017 con los ya existentes en esa fecha, año en el que se publicó una revisión que dejaba abierta la propuesta de seguir buscando un modelo con un rendimiento adecuado para los SUH. Y así, a partir de ella, generar distintas recomendaciones que ayuden a definir el papel que pueden tener estos modelos o escalas en la mejora de la indicación de obtención de los HC, así como en la toma inmediata de otras decisiones diagnóstico-terapéuticas (administración precoz y adecuada del tratamiento antibiótico, solicitud de estudios complementarios y otras muestras microbiológicas, intensidad del soporte hemodinámico, necesidad de ingreso, etc.) 相似文献
63.
Juan Marco FigueiraGonalves Rafael Golpe Cristbal Esteban Miguel ngel GarcíaBello Nagore BlancoCid Amaia Aramburu Ignacio GarcíaTalavera María Dolores MartínMartínez Adrian BaezaRuiz Andrea ExpsitoMarrero 《The clinical respiratory journal》2022,16(7):504
BackgroundChronic obstructive pulmonary disease (COPD) is a complex and heterogeneous condition, in which taking into consideration clinical phenotypes and multimorbidity is relevant to disease management. Network analysis, a procedure designed to study complex systems, allows to represent connections between the distinct features found in COPD.MethodsNetwork analysis was applied to a cohort of patients with COPD in order to explore the degree of connectivity between different diseases, taking into account the presence of two phenotypic traits commonly used to categorize patients in clinical practice: chronic bronchitis (CB+/CB−) and the history of previous severe exacerbations (Ex+/Ex−). The strength of association between diseases was quantified using the correlation coefficient Phi (ɸ).ResultsA total of 1726 patients were included, and 91 possible links between 14 diseases were established. Although the four phenotypically defined groups presented a similar underlying comorbidity pattern, with special relevance for cardiovascular diseases and/or risk factors, classifying patients according to the presence or absence of CB implied differences between groups in network density (mean ɸ: 0.098 in the CB− group and 0.050 in the CB+ group). In contrast, between‐group differences in network density were small and of questionable significance when classifying patients according to prior exacerbation history (mean ɸ: 0.082 among Ex− subjects and 0.072 in the Ex+ group). The degree of connectivity of any given disease with the rest of the network also varied depending on the selected phenotypic trait. The classification of patients according to the CB−/CB+ groups revealed significant differences between groups in the degree of conectivity between comorbidities. On the other side, grouping the patients according to the Ex−/Ex+ trait did not disclose differences in connectivity between network nodes (diseases).ConclusionsThe multimorbidity network of a patient with COPD differs according to the underlying clinical characteristics, suggesting that the connections linking comorbidities between them vary for different phenotypes and that the clinical heterogeneity of COPD could influence the expression of latent multimorbidity. Network analysis has the potential to delve into the interactions between COPD clinical traits and comorbidities and is a promising tool to investigate possible specific biological pathways that modulate multimorbidity patterns. 相似文献
64.
Xinran Shen Shunna Lin Hui Li Nubiya Amaerjiang Wen Shu Menglong Li Huidi Xiao Sofia Segura-Prez Rafael Prez-Escamilla Xin Fan Yifei Hu 《Nutrients》2022,14(14)
Background: Emergency cesarean section (EMCS) and breastfeeding difficulties increase the risk of postpartum depressive (PPD) symptoms. Early initiation of breastfeeding (EIBF) may not only alleviate PPD symptoms but also facilitate subsequent breastfeeding success. EMCS is a risk factor for not practicing EIBF. Therefore, it is important to understand the relationship between EMCS, EIBF, and PPD symptoms. Methods: We conducted a prospective cohort study in three areas of China. At baseline, a total of 965 mothers completed electronic questionnaires within 72 h postpartum. Women were screened for PPD symptoms using the Edinburgh Postpartum Depression Scale (EPDS). Multivariate logistic regression was used to identify the determinants of PPD symptoms. Mediation analysis was used to determine if EIBF mediated the relationship between delivery mode or breastfeeding education source and PPD symptoms. Results: The prevalence of EIBF was 40.6%; 14% of 965 mothers experienced EMCS, and 20.4% had PPD symptoms. The risk factors for developing PPD symptoms were excessive gestational weight gain (adjusted odds ratio [aOR] = 1.55, confidence interval [95% CI]: 1.03–2.33, p = 0.037) and EMCS (aOR = 2.05, 95% CI: 1.30–3.25, p = 0.002). The protective factors for developing PPD symptoms were monthly household income over CNY 10000 (aOR = 0.68, 95% CI: 0.47–0.97, p = 0.034), EIBF (aOR = 0.49, 95% CI: 0.34–0.72, p < 0.001), and prenatal breastfeeding education from nurses (aOR = 0.46, 95% CI: 0.29–0.73, p = 0.001). EIBF indirectly affected PPD symptoms in patients who had undergone EMCS (percentage mediated [PM] = 16.69, 95% CI: 7.85–25.25, p < 0.001). The source of breastfeeding education through EIBF also affected PPD symptoms (PM = 17.29, 95% CI: 3.80–30.78, p = 0.012). Conclusion: The association between EMCS on PPD symptoms was mediated by EIBF. By providing breastfeeding education, nurses could also help alleviate PPD symptoms. 相似文献
65.
Michael Nazarkovsky Albina Mikhraliieva Carlos A. Achete Luiz Anastacio Alves Joyce Araujo Brulio S. Archanjo Jos Júnior Frana de Barros Liana Monteiro da Fonseca Cardoso Jos Nelson S. S. Couceiro Fernanda Davi Marques Bruno S. Oliveira Rafael Nascimento Dias de Souza Ayla Josma Teixeira Thiago L. Vasconcelos Vladimir Zaitsev 《RSC advances》2022,12(23):14342
Rational synthesis and simple methodology for the purification of large (35–45 nm in lateral size) and flat (1.0–1.5 nm of height) nitrogen-doped graphene oxide quantum dots (GOQDs) are presented. The methodology allows robust metal-free and acid-free preparation of N-GOQDs with a yield of about 100% and includes hydrothermal treatment of graphene oxide with hydrogen peroxide and ammonia. It was demonstrated that macroscopic impurities can be separated from N-GOQD suspension by their coagulation with 0.9% NaCl solution. Redispersible in water and saline solutions, particles of N-GOQDs were characterized using tip-enhanced Raman spectroscopy (TERS), photoluminescent, XPS, and UV-VIS spectroscopies. The size and morphology of N-GOQDs were studied by dynamic light scattering, AFM, SEM, and TEM. The procedure proposed allows nitrogen-doped GOQDs to be obtained, having 60–51% of carbon, 34–45% of oxygen, and up to 7.2% of nitrogen. The N-GOQD particles obtained in two hours of synthesis contain only pyrrolic defects of the graphene core. The fraction of pyridine moieties grows with the time of synthesis, while the fraction of quaternary nitrogen declines. Application of TERS allows demonstration that the N-GOQDs consist of a graphene core with an average crystallite size of 9 nm and an average distance between nearest defects smaller than 3 nm. The cytotoxicity tests reveal high viability of the monkey epithelial kidney cells Vero in the presence of N-GOQDs in a concentration below 60 mg L−1. The N-GOQDs demonstrate green luminescence with an emission maximum at 505 nm and sedimentation stability in the cell culture medium.This paper reveals the methodology for robust preparation of purified nitrogen-doped graphene oxide quantum dots with non-cytotoxic activity against monkey epithelial kidney cells (Vero ATCC® CCL-81™). 相似文献
66.
67.
68.
69.
70.
Javier Berraondo Laura NovellaFrancisco Sanz Rafael LluchEnrique de Casimiro Tomás Lloret 《Archivos de bronconeumología》2013
Amyloidosis is a systemic disease caused by abnormal deposition of amyloid material that is detected with Congo red staining and is difficult to diagnose. Involvement of the tracheobronchial tree is rare and is a challenge for pulmonologists because of the wide differential diagnosis of this disease. We present two cases where tracheobronchial affectation has been observed: in one of them as a primary disease, and in another as secondary affectation. The use of bronchoscopic techniques is essential for the diagnosis of tracheobronchial involvement. In the absence of an effective drug therapy, local management of this disease with endoscopic techniques for bronchial repermeabilization is able to provide clinical improvement and expand the treatment options and prognosis in this disease. 相似文献