全文获取类型
收费全文 | 28549篇 |
免费 | 1498篇 |
国内免费 | 104篇 |
专业分类
耳鼻咽喉 | 275篇 |
儿科学 | 828篇 |
妇产科学 | 610篇 |
基础医学 | 3670篇 |
口腔科学 | 783篇 |
临床医学 | 2029篇 |
内科学 | 7672篇 |
皮肤病学 | 879篇 |
神经病学 | 2335篇 |
特种医学 | 670篇 |
外国民族医学 | 1篇 |
外科学 | 4327篇 |
综合类 | 143篇 |
一般理论 | 6篇 |
预防医学 | 2271篇 |
眼科学 | 505篇 |
药学 | 1543篇 |
中国医学 | 116篇 |
肿瘤学 | 1488篇 |
出版年
2023年 | 164篇 |
2022年 | 238篇 |
2021年 | 814篇 |
2020年 | 364篇 |
2019年 | 677篇 |
2018年 | 1103篇 |
2017年 | 628篇 |
2016年 | 622篇 |
2015年 | 697篇 |
2014年 | 856篇 |
2013年 | 1216篇 |
2012年 | 2047篇 |
2011年 | 2245篇 |
2010年 | 1156篇 |
2009年 | 994篇 |
2008年 | 1915篇 |
2007年 | 1989篇 |
2006年 | 1892篇 |
2005年 | 1849篇 |
2004年 | 1580篇 |
2003年 | 1503篇 |
2002年 | 1398篇 |
2001年 | 692篇 |
2000年 | 721篇 |
1999年 | 575篇 |
1998年 | 174篇 |
1997年 | 141篇 |
1996年 | 125篇 |
1995年 | 107篇 |
1994年 | 93篇 |
1993年 | 76篇 |
1992年 | 191篇 |
1991年 | 198篇 |
1990年 | 138篇 |
1989年 | 129篇 |
1988年 | 104篇 |
1987年 | 84篇 |
1986年 | 82篇 |
1985年 | 76篇 |
1984年 | 71篇 |
1983年 | 48篇 |
1982年 | 22篇 |
1981年 | 27篇 |
1980年 | 20篇 |
1979年 | 35篇 |
1978年 | 27篇 |
1977年 | 36篇 |
1974年 | 27篇 |
1973年 | 31篇 |
1972年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
Ángel Becerra Héctor Trujillo Lucía Valencia Aurelio Rodríguez‐Pérez 《Brazilian Journal of Anesthesiology》2019,69(2):200-203
Background and objectives
A prompt and effective management of trauma patient is necessary. The aim of this case report is to highlight the importance of intraoperative echocardiography as a useful tool in patients suffering from refractory hemodynamic instability no otherwise explained.Case report
A 41 year‐old woman suffered a car accident. At the emergency department, no abnormalities were found in ECG or chest X‐ray. Abdominal ultrasound revealed the presence of abdominal free liquid and the patient was submitted to urgent exploratory laparotomy. Nevertheless, she persisted suffering arterial hypotension and metabolic acidosis. Looking for the reason of her hemodynamic instability, intraoperative transthoracic echocardiography was performed, finding out the presence of pericardial effusion. Once the cardiac surgeon extracted pericardial clots, patient's situation improved clinically and analytically.Conclusion
Every anesthesiologist should be able to use the intraoperative echocardiography as an effective tool in order to establish the appropriate measures to promote the survival of patients suffering severe trauma. 相似文献2.
Primary cutaneous anaplastic large cell lymphomas with 6p25.3 rearrangement exhibit particular histological features
下载免费PDF全文
![点击此处可从《Histopathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
3.
N. S. Hari Narayana Moorthy Sergio F. Sousa Maria J. Ramos Pedro A. Fernandes 《Medicinal chemistry research》2016,25(7):1340-1357
Farnesyltransferase (FTase) is one of the prenyltransferase family enzymes that catalyse the transfer of 15-membered isoprenoid (farnesyl) moiety to the cysteine of CAAX motif-containing proteins including Rho and Ras family of G proteins. Inhibitors of FTase act as drugs for cancer, malaria, progeria and other diseases. In the present investigation, we have developed two structure-based pharmacophore models from protein–ligand complex (3E33 and 3E37) obtained from the protein data bank. Molecular dynamics (MD) simulations were performed on the complexes, and different conformers of the same complex were generated. These conformers were undergone protein–ligand interaction fingerprint (PLIF) analysis, and the fingerprint bits have been used for structure-based pharmacophore model development. The PLIF results showed that Lys164, Tyr166, TrpB106 and TyrB361 are the major interacting residues in both the complexes. The RMSD and RMSF analyses on the MD-simulated systems showed that the absence of FPP in the complex 3E37 has significant effect in the conformational changes of the ligands. During this conformational change, some interactions between the protein and the ligands are lost, but regained after some simulations (after 2 ns). The structure-based pharmacophore models showed that the hydrophobic and acceptor contours are predominantly present in the models. The pharmacophore models were validated using reference compounds, which significantly identified as HITs with smaller RMSD values. The developed structure-based pharmacophore models are significant, and the methodology used in this study is novel from the existing methods (the original X-ray crystallographic coordination of the ligands is used for the model building). In our study, along with the original coordination of the ligand, different conformers of the same complex (protein–ligand) are used. It concluded that the developed methodology is significant for the virtual screening of novel molecules on different targets. 相似文献
4.
Khaled Adil Marija Popovic Fabio L. Cury Sergio L. Faria Marie Duclos Luis Souhami 《Practical radiation oncology》2019,9(1):24-28
Purpose
This study aimed to investigate 3 planning target volume (PTV) margin expansions and determine the most appropriate volume to be used in bladder preservation therapy when using daily cone beam computed tomography (CBCT). We aimed to establish whether a smaller PTV expansion is feasible without risking geographical miss.Methods and materials
The study included patients with bladder cancer who were treated with a hypofractionated course of radiation therapy delivered with intensity modulated radiation therapy. The clinical target volume (CTV) was the whole empty bladder, and the PTV consisted of a 1.5-cm margin around the bladder (PTV1.5 cm). Patients underwent daily CBCT imaging before treatment to assess the bladder volume and ensure accurate positioning. We investigated 2 additional smaller PTV margin expansions to determine the most appropriate volume to be used with CBCT as a daily image guided radiation therapy modality. These margins were created retrospectively on every CBCT. The first additional volume was a uniform PTV margin of the surrounding 1 cm (PTV1 cm). When considering that the majority of the internal bladder movement was due to the variation in filling that occurs in the superior and anterior directions, a second volume of an anisotropic PTV margin with a 1.5-cm superior/anterior and 1 cm in other directions (PTV1/1.5 cm) was created. We recorded the frequency and measured the volume of bladder falling out of each PTV based on the daily CBCT.Results
For the purpose of this study, we considered an arbitrary 5 cm3 of CTV falling out of the designated PTV as a clinically significant volumetric miss. The frequency of such a miss when applying the uniform PTV1 cm was 1%. However, when applying the uniform PTV1.5 cm and anisotropic PTV1/1.5 cm margins, the frequency was 0.5% and 0.5%, respectively.Conclusions
The anisotropic PTV expansion of 1.5 cm superiorly and anteriorly and 1 cm in all other directions around the bladder (CTV) provides a safe PTV approach when daily CBCT imaging is used to localize an empty bladder. 相似文献5.
Maria Gonzalez-Cao Cristina Carrera Juan Francisco Rodriguez Moreno Pedro Rodríguez-Jiménez Mónica Antoñanzas Basa Rosa Feltes Ochoa Teresa Puertolas Eva Muñoz-Couselo José Luis Manzano Ivan Marquez-Rodas Juan Martín-Liberal Ainara Soria Pilar Lopez Criado Almudena Garcia-Castaño Aram Boada Pablo Ayala de Miguel Susana Puig Guillermo Crespo Alfonso Berrocal 《Journal of the American Academy of Dermatology》2021,84(5):1412-1415
6.
7.
Estefany I. Medina-Reyes Carolina Rodríguez-Ibarra Daniel Díaz-Urbina Alejandro Déciga-Alcaraz Normal L. Delgado-Buenrostro Yolanda I. Chirino José Pedraza-Chaverri 《Journal of applied toxicology : JAT》2022,42(8):1411-1419
Food-grade titanium dioxide (E171) is widely used as a food additive, and it is known that after oral consumption, E171 is translocated into the bloodstream reaching the highest titanium level at 6 h. E171 is accumulated in some organs triggering toxicity, but the effects on the blood parameters after oral consumption have been less studied. Recently, evidence shows that oral exposure to E171 induces behavioral signs of anxiety and depression. The relation between blood alterations and psychiatric disorders has been previously demonstrated. However, the oral exposure to E171 effects on alterations in blood parameters and effects linked to alterations in animal behavior has not been explored. In this short communication, we aimed to investigate the effects of E171 on specific blood parameters (hematocrit, hemoglobin, number of erythrocytes, and leukocytes) and anxiety and compulsive-like behavior in males and females orally exposed to ~5 mg/kg for 4 weeks. The results showed that E171 decreased hematocrit and hemoglobin in male but not in female mice while leukocyte and erythrocyte count remained unaltered. Oral consumption of E171 decreased the levels of anxiety-like behavior in females but not in male mice, while compulsive-like behavior was increased in both male and female mice. 相似文献
8.
9.
10.
José A. Lorente Pablo Cardinal-Fernández Diego Muñoz Fernando Frutos-Vivar Arnaud W. Thille Carlos Jaramillo Aida Ballén-Barragán José M. Rodríguez Oscar Peñuelas Guillermo Ortiz José Blanco Bruno Valle Pinheiro Nicolás Nin María del Carmen Marin Andrés Esteban Taylor B. Thompson 《Intensive care medicine》2015,41(11):1921-1930