全文获取类型
收费全文 | 44048篇 |
免费 | 2325篇 |
国内免费 | 116篇 |
专业分类
耳鼻咽喉 | 611篇 |
儿科学 | 851篇 |
妇产科学 | 858篇 |
基础医学 | 5628篇 |
口腔科学 | 2162篇 |
临床医学 | 3321篇 |
内科学 | 11358篇 |
皮肤病学 | 830篇 |
神经病学 | 3631篇 |
特种医学 | 814篇 |
外科学 | 5689篇 |
综合类 | 234篇 |
一般理论 | 16篇 |
预防医学 | 3961篇 |
眼科学 | 941篇 |
药学 | 3084篇 |
中国医学 | 182篇 |
肿瘤学 | 2318篇 |
出版年
2024年 | 30篇 |
2023年 | 286篇 |
2022年 | 211篇 |
2021年 | 854篇 |
2020年 | 460篇 |
2019年 | 958篇 |
2018年 | 1733篇 |
2017年 | 1082篇 |
2016年 | 1073篇 |
2015年 | 1340篇 |
2014年 | 1452篇 |
2013年 | 2096篇 |
2012年 | 4050篇 |
2011年 | 4122篇 |
2010年 | 2135篇 |
2009年 | 1529篇 |
2008年 | 3417篇 |
2007年 | 3507篇 |
2006年 | 3361篇 |
2005年 | 3257篇 |
2004年 | 2853篇 |
2003年 | 2589篇 |
2002年 | 2399篇 |
2001年 | 148篇 |
2000年 | 128篇 |
1999年 | 144篇 |
1998年 | 118篇 |
1997年 | 96篇 |
1996年 | 102篇 |
1995年 | 88篇 |
1994年 | 75篇 |
1993年 | 72篇 |
1992年 | 59篇 |
1991年 | 59篇 |
1990年 | 30篇 |
1989年 | 33篇 |
1988年 | 20篇 |
1987年 | 20篇 |
1986年 | 23篇 |
1985年 | 31篇 |
1984年 | 43篇 |
1983年 | 27篇 |
1982年 | 48篇 |
1981年 | 31篇 |
1980年 | 41篇 |
1979年 | 12篇 |
1978年 | 14篇 |
1976年 | 12篇 |
1975年 | 16篇 |
1974年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Abdulbaqi Al-Toma Marije S Goerres Jos W R Meijer B Mary E von Blomberg Peter J Wahab Jo A M Kerckhaert Chris J J Mulder 《Clinical gastroenterology and hepatology》2006,4(11):1322-7; quiz 1300
BACKGROUND & AIMS: Refractory celiac disease (RCD) may be subdivided into RCD types I and II with phenotypically normal and aberrant intraepithelial T-cell populations, respectively. In RCD II, transition into enteropathy-associated T-cell lymphoma (EATL) is seen frequently. We have evaluated the effect of cladribine (2-CDA), a purine analogue inducing T-cell depletion, on clinical, histopathologic, and immunologic parameters, as well as the toxicity and side effects in a group of RCD II patients. METHODS: Between 2000 and 2005, 17 patients were included (8 men, 9 women). All patients had a clonal rearrangement of the T-cell receptor gamma gene and immunophenotyping showed an aberrant T-cell population lacking surface expression of CD3, CD8, and T-cell receptor alphabeta, in the presence of expression of surface CD103 and intracytoplasmic CD3. Treatment consisted of 2-CDA (0.1 mg/kg/day) intravenously for 5 days, given in 1-3 courses every 6 months depending on the response. RESULTS: All patients tolerated 2-CDA without serious side effects. Six patients (35.8%) showed a clinical improvement (weight gain, improvement of diarrhea, and hypoalbuminemia). In 10 patients (58.8%) a significant histologic improvement and in 6 patients (35.2%) a significant decrease in aberrant T cells was seen. Seven patients (41.1%) developed EATL and died subsequently. One patient died of progressive refractory state with emaciation. CONCLUSIONS: Treatment with 2-CDA in RCD II is feasible, well tolerated, and can induce clinical and histologic improvement as well as a significant decrease of aberrant T cells in a subgroup of patients, albeit it does not prevent EATL development. However, the earlier reported potential risk of precipitating an overt lymphoma should be taken into consideration. 相似文献
82.
Use of stereotactic PET images in dosimetry planning of radiosurgery for brain tumors: clinical experience and proposed classification. 总被引:13,自引:0,他引:13
Marc Levivier Nicolas Massager David Wikler José Lorenzoni Salvador Ruiz Daniel Devriendt Philippe David Fran?oise Desmedt Stéphane Simon Paul Van Houtte Jacques Brotchi Serge Goldman 《Journal of nuclear medicine》2004,45(7):1146-1154
We developed a technique that allows the routine integration of PET in stereotactic neurosurgery, including radiosurgery. We report our clinical experience with the combined use of metabolic (i.e., PET) and anatomic (i.e., MRI and CT) images for the radiosurgical treatment of brain tumors. We propose a classification describing the relative role of the information provided by PET in this multimodality image-guided approach. METHODS: Between December 1999 and March 2003, 57 patients had stereotactic PET as part of their image acquisition for the planning of gamma knife radiosurgery. Together with stereotactic MRI and CT, stereotactic PET images were acquired on the same day using either (18)F-FDG or (11)C-methionine. PET images were imported in the planning software for the radiosurgery dosimetry, and the target volume was defined using the combined information of PET and MRI or CT. To analyze the specific contribution of the PET findings, we propose a classification that reflects the strategy used to define the target volume. RESULTS: The patients were offered radiosurgery with PET guidance when their tumor was ill-defined and we anticipated some limitation of target definition on MRI alone. This represents 10% of the radiosurgery procedures performed in our center during the same period of time. There were 40 primary brain lesions, 7 metastases, and 10 pituitary adenomas. Abnormal PET uptake was found in 62 of 72 targets (86%), and this information altered significantly the MRI-defined tumor in 43 targets (69%). CONCLUSION: The integration of PET in radiosurgery provides additional information that opens new perspectives for the optimization of the treatment of brain tumors. 相似文献
83.
Guilherme Santoro-Lopes Erika Ferraz de Gouvêa Rodrigo Carreira M Monteiro Rodrigo Castelo Branco José Rodolfo Rocco Márcia Halpern Adriana Lúcia Pires Ferreira Elaine Gama Pessoa de Araújo Samanta T Basto Vinicius Gomes Silveira Joaquim Ribeiro-Filho 《Liver transplantation》2005,11(2):203-209
Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of infection after orthotopic liver transplantation (OLT). Colonization with MRSA is associated with a higher risk of infection. Previous studies have shown a high prevalence of MRSA colonization among OLT candidates. However, the risk of colonization with MRSA after OLT is still unclear. The objective of this study was to estimate the incidence and the factors associated with colonization with MRSA after OLT. This was a prospective cohort study including patients submitted to OLT between the years 2000 and 2002. Surveillance cultures of nasal swab specimens were performed within the 1st 72 hours of hospital admission and, subsequently, on weeks 2, 6, 13, and 26. Patients whose baseline cultures revealed nasal carriage of MRSA were excluded. A total of 60 patients were included in the study. The median follow-up was 72 days. A total of 9 patients (15%) became colonized. In multiple logistic regression analyses, the use of a urinary catheter for > or =5 days (P = .006), postoperative bleeding at the surgical site (P = .009), and preoperative use of fluoroquinolones (P = .08) were associated with a higher risk of colonization. Patients without any of these risk factors did not become colonized. In conclusion, nasal carriage of MRSA is frequently acquired after OLT. Periodic postoperative screening for MRSA carriage should be an integral component in programs designed to reduce nosocomial MRSA transmission in these patients. Further studies are needed to set up and validate a predictive model that could allow targeting postoperative screening to high-risk OLT recipients. 相似文献
84.
José A Pe?agarícano Nikos Papanikolaou Yulong Yan Emad Youssef Vaneerat Ratanatharathorn 《Radiotherapy and oncology》2005,76(1):72-78
BACKGROUND AND PURPOSE: Helical tomotherapy can eliminate the need for junction lines. The goal of this study is to evaluate tomotherapy in the delivery of CSA radiation and measurement of plan quality using physical parameters in comparing conventional (CSA-RT) and helical tomotherapy (CSA-TOMO) plans. PATIENTS AND METHODS: CSA-TOMO and CSA-RT plans were created for dosimetric comparison. Integral dose values were calculated. The ratios D50% (dose received by 50% of the organ at risk's volume) and D10% (dose received by 10% of the organ at risk's volume) were calculated representing large volumes and small volumes of organs at risk receiving significant dose. RESULTS: When considering D50% and D10%, CSA-TOMO has a dosimetric advantage over CSA-RT for most organs at risk. The body integral dose was higher for the CSA-TOMO plan by approximately 6.5%. CONCLUSIONS: Tomotherapy is a feasible alternative for treatment of CSA. Analysis shows that tomotherapy improves dose ratios over conventional radiation for most organs at risk. The impact of a small increase in whole body integral dose is unknown. Long-term follow-up will be needed to answer this question as others have argued of the possibility of increased risk of secondary malignancies due to delivery of radiotherapy with IMRT. 相似文献
85.
Guilherme Janson Karina Santana Cruz Donald G Woodside Angelos Metaxas Marcos Roberto de Freitas José Fernando Castanha Henriques 《American journal of orthodontics and dentofacial orthopedics》2004,126(4):451-463
The objective of this study was to evaluate the dentoskeletal changes consequent to orthodontic treatment in subjects with Class II subdivision malocclusions, treated with asymmetric extractions, compared with a normal-occlusion control group. The sample consisted of 3 groups, with 30 subjects in each: normal-occlusion subjects (group 1), untreated Class II subdivision subjects (group 2), and Class II subdivision patients treated with asymmetric extractions (group 3). All subjects had a full complement of permanent teeth at the beginning of treatment. The average ages of the subjects were 22.42, 15.76, and 18.57 years, respectively, in groups 1, 2, and 3. Measurements of relative differences in the spatial position of dental and skeletal bilateral landmarks were obtained from the submentovertex and posteroanterior cephalometric (PA) radiographs. The t test for independent samples was used to compare group 1 with groups 2 and 3 at different times. Results from the submentovertex radiograph showed that asymmetric extractions in Class II subdivision malocclusions will maintain the differences in the anteroposterior positions of right and left, maxillary and mandibular first molars, as would be expected with the treatment protocols used. There were no significant skeletal changes that could be attributed to the treatment approaches investigated or transverse collateral effects with the asymmetric mechanics used. It was also demonstrated that treatment of Class II subdivision malocclusions with asymmetric extractions produced corrections of maxillary and mandibular dental midline deviations with the midsagittal plane, without canting the occlusal plane or any other investigated horizontal plane, as seen in the PA radiograph. Treatment of Class II subdivision malocclusions with asymmetric extractions constitutes a beneficial approach to this problem. 相似文献
86.
Jos F M de Jonghe Kees J Kalisvaart Marty Dijkstra Huib van Dis Ralph Vreeswijk Martin G Kat Piet Eikelenboom Tjeerd van der Ploeg Willem A van Gool 《The American journal of geriatric psychiatry》2007,15(2):112-121
OBJECTIVES: The authors investigated prodromal delirium symptoms in elderly patients undergoing hip surgery. METHODS: This was a prospective cohort study in the setting of a large medical school-affiliated general hospital in Alkmaar, The Netherlands. Participants were patients undergoing hip surgery aged 70 and older at risk for delirium. Before surgery, patients were randomized to low-dose prophylactic haloperidol treatment or placebo. Daily assessments were based on patient interviews with the Mini-Mental State Examination and Digit Span test. The Delirium Rating Scale-Revised (DRS-R-98) was used to measure early symptoms during the prodromal phase before the onset of delirium. RESULTS: Data of 66 patients with delirium were compared with those of 35 at-risk patients who did not develop delirium: 14 of 66 patients (21%) had delirium on the day of surgery or early the day after, 32 of 66 (48%) on the second day, 14 of 66 on the third, and six of 66 (9%) on the fourth. The average DRS-R-98 total scores on day -4 to day -1 before delirium were 1.9 for the comparison group patients and 5.0, 4.3, 5.8, and 10.7 for patients with postoperative delirium. Multivariate analysis showed that the early symptoms memory impairments, incoherence, disorientation, and underlying somatic illness predict delirium. CONCLUSIONS: Most elderly patients undergoing hip surgery with postoperative delirium already have early symptoms in the prodromal phase of delirium. These findings are potentially useful for screening purposes and for optimizing prevention strategies targeted at reducing the incidence of postoperative delirium. 相似文献
87.
Catarina Eira Jordi Miquel José Vingada Jordi Torres 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2006,51(2):119-122
Gongylonema neoplasticum was identified in the oesophagus of 14 wild rabbits (Oryctolagus cuniculus) from Portugal. This is the first record of Gongylonema neoplasticum in a naturally infected lagomorph species in Europe. This paper presents the most relevant measurements of adult worms and
some of their surface features seen by scanning electron microscopy. Epidemiological aspects of G. neoplasticum such as geographical distribution, host spectrum and biological features are discussed. 相似文献
88.
Alfredo Avellaneda Fernández álvaro Pérez Martín Maravillas Izquierdo Martínez Mar Arruti Bustillo Francisco Javier Barbado Hernández Javier de la Cruz Labrado Rafael Díaz-Delgado Pe?as Eduardo Gutiérrez Rivas Cecilia Palacín Delgado José Ramón Ramón Giménez Javier Rivera Redondo 《Atencion primaria / Sociedad Espa?ola de Medicina de Familia y Comunitaria》2009,41(10):e1-e5
89.
Edmo Atique Gabriel Rafael Fagionato Locali Carla Cristina Romano Alberto José da Silva Duarte José Honório Palma Enio Buffolo 《European journal of cardio-thoracic surgery》2007,31(3):406-412
OBJECTIVE: The objective of this study is to evaluate the inflammatory response caused by endovascular stents in the treatment of aortic aneurysms. METHODS: Twenty-five patients underwent endovascular stent treatment from March through December 2005. The evolution of mediators (sedimentation velocity, C reactive protein, interleukin-6, interleukin-8, tumor necrosis factor-alpha, intercellular adhesion molecule-1, l-selectin), inflammatory cells (leukocytes, lymphocytes, platelets), serum creatinine and body temperature within preoperative period and in the following postoperative periods--1, 6, 24 and 48 h, 7 days, 1-3 months, was analyzed. In order to achieve statistic significance, Friedman test and Wilcoxon test were used, with index of significance of 5% (p<0.05). RESULTS: Peak values of sedimentation velocity, C reactive protein and interleukin-6 were observed at 7 days (p<0.0001), 48 h (p<0.0001) and 24h (p<0.0001), respectively. Tumor necrosis factor-alpha and interleukin-8 did not show statistically significant variability during the entire follow-up. In terms of intercellular adhesion molecule-1 and l-selectin, their expressive values were found in late phase of follow-up, although without statistical significance. Elevation of leukocytes count occurred in premature phase of follow-up (p<0.0001), while lymphocyte and platelet count occurred in a late phase of follow-up (p<0.0001). Serum levels of creatinine did not show significant variability during follow-up. The period between 24 and 48 h corresponded to major frequency for fever (p<0.0001). CONCLUSION: Individual mediators analysis and inflammatory cells demonstrated variability of their values during postoperative follow-up. This could help in the analysis of the inflammatory response evolution caused by endovascular stent treatment for aortic aneurysms in premature and late phases after implantation of the vascular prosthesis. 相似文献
90.
José María Calvo-Romero Esther María Lima-Rodríguez 《European journal of emergency medicine》2004,11(6):348-350
We describe a pregnant woman with ovarian hyperstimulation syndrome with bilateral pleural effusion and ascites. Ovarian hyperstimulation syndrome is an iatrogenic complication of ovarian stimulation, characterized by a massive crossing of a protein-rich fluid from the vascular compartment into the peritoneal, pleural, or to a lesser extent, pericardial cavities. Management is usually conservative, with fluid and electrolytes correction and thromboprophylaxis. Prevention is very difficult, but an age younger than 35 years, low body mass index, polycystic ovarian disease, a high number of follicles, a high plasma oestradiol concentration, pregnancy, hyperandrogenism, and hypothyroidism are predisposing factors. 相似文献