全文获取类型
收费全文 | 2236篇 |
免费 | 111篇 |
国内免费 | 79篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 102篇 |
妇产科学 | 36篇 |
基础医学 | 195篇 |
口腔科学 | 50篇 |
临床医学 | 210篇 |
内科学 | 581篇 |
皮肤病学 | 75篇 |
神经病学 | 130篇 |
特种医学 | 299篇 |
外科学 | 286篇 |
综合类 | 34篇 |
预防医学 | 165篇 |
眼科学 | 32篇 |
药学 | 123篇 |
中国医学 | 8篇 |
肿瘤学 | 88篇 |
出版年
2023年 | 9篇 |
2022年 | 8篇 |
2021年 | 42篇 |
2020年 | 20篇 |
2019年 | 52篇 |
2018年 | 51篇 |
2017年 | 37篇 |
2016年 | 32篇 |
2015年 | 36篇 |
2014年 | 49篇 |
2013年 | 65篇 |
2012年 | 74篇 |
2011年 | 97篇 |
2010年 | 79篇 |
2009年 | 82篇 |
2008年 | 95篇 |
2007年 | 121篇 |
2006年 | 85篇 |
2005年 | 82篇 |
2004年 | 65篇 |
2003年 | 77篇 |
2002年 | 69篇 |
2001年 | 69篇 |
2000年 | 76篇 |
1999年 | 53篇 |
1998年 | 94篇 |
1997年 | 82篇 |
1996年 | 66篇 |
1995年 | 62篇 |
1994年 | 53篇 |
1993年 | 48篇 |
1992年 | 39篇 |
1991年 | 29篇 |
1990年 | 36篇 |
1989年 | 50篇 |
1988年 | 45篇 |
1987年 | 35篇 |
1986年 | 35篇 |
1985年 | 37篇 |
1984年 | 29篇 |
1983年 | 20篇 |
1982年 | 20篇 |
1981年 | 14篇 |
1980年 | 14篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1977年 | 18篇 |
1976年 | 17篇 |
1975年 | 13篇 |
1969年 | 4篇 |
排序方式: 共有2426条查询结果,搜索用时 15 毫秒
71.
AB Rossi JJ Leyden AS Pappert A Ramaswamy A Nkengne R Ramaswamy M Nighland 《Journal of the European Academy of Dermatology and Venereology》2011,25(4):398-402
Background Post‐inflammatory hyperpigmentation (PIH) is a common occurrence in patients with acne vulgaris, particularly in those with skin of colour. Aims A previous study has demonstrated the benefit of tretinoin (retinoic acid) in the treatment of PIH; however, there is currently no standard protocol to evaluate change in PIH following treatment. Based on these findings, we performed a pilot, exploratory, blinded, intraindividual‐controlled methodology study that consisted of a photographic assessment protocol with facial mapping. Materials and methods The study was based on a secondary analysis of a phase 4, community‐based trial of 544 acne patients who were treated with tretinoin gel microsphere 0.04% or 0.1%. Only patients with Fitzpatrick types III–V (skin of colour) were included in the study; subjects with Fitzpatrick skin type VI were excluded because the photographic assessment did not allow for proper evaluation. Results Despite the small number of subjects evaluated (n = 25), the results revealed consistent assessment of improvement in PIH between two independent graders (weighted κ = 0.84). Conclusion Further study with a larger population is recommended to validate the accuracy of this method. 相似文献
72.
Ramon Farré Jordi Otero Isaac Almendros Daniel Navajas 《Archivos de bronconeumologia》2018,54(1):31-38
Lung biofabrication is a new tissue engineering and regenerative development aimed at providing organs for potential use in transplantation. Lung biofabrication is based on seeding cells into an acellular organ scaffold and on culturing them in an especial purpose bioreactor. The acellular lung scaffold is obtained by decellularizing a non-transplantable donor lung by means of conventional procedures based on application of physical, enzymatic and detergent agents. To avoid immune recipient's rejection of the transplanted bioengineered lung, autologous bone marrow/adipose tissue-derived mesenchymal stem cells, lung progenitor cells or induced pluripotent stem cells are used for biofabricating the bioengineered lung. The bioreactor applies circulatory perfusion and mechanical ventilation with physiological parameters to the lung during biofabrication. These physical stimuli to the organ are translated into the stem cell local microenvironment – e.g. shear stress and cyclic stretch – so that cells sense the physiological conditions in normally functioning mature lungs. After seminal proof of concept in a rodent model was published in 2010, the hypothesis that lungs can be biofabricated is accepted and intense research efforts are being devoted to the topic. The current experimental evidence obtained so far in animal tests and in ex vivo human bioengineered lungs suggests that the date of first clinical tests, although not immediate, is coming. Lung bioengineering is a disrupting concept that poses a challenge for improving our basic science knowledge and is also an opportunity for facilitating lung transplantation in future clinical translation. 相似文献
73.
Forty-three professional and amateur athletes with persistent shoulder pain that interfered with their sports activities were evaluated by computed tomographic (CT) arthrography. In 19 patients, glenohumeral instability (14 anterior, two posterior, three multidirectional) was diagnosed with CT arthrography based on the simultaneous presence of labral and capsular lesions. The findings were crucial in establishing the diagnosis of instability in six patients in whom the condition was not suggested or could not be confirmed clinically. Another significant injury consisted of labral lesions not associated with glenohumeral instability. These tears often involved the anterior and parasuperior segments of this structure. Other, less frequently detected lesions included segmental labral enlargement and several labra with abnormal orientation (everted labrum). Early onset of degenerative disease was present in many athletes, especially those with a long history of sports activity. CT arthrographic findings were correlated with arthroscopic or surgical results in 19 patients. 相似文献
74.
Rokey R; Verani MS; Bolli R; Kuo LC; Ford JJ; Wendt RE; Schneiders NJ; Bryan RN; Roberts R 《Radiology》1986,158(3):771-774
The feasibility of using magnetic resonance (MR) imaging to estimate myocardial infarct size was explored in an in vitro model using only the inherent differences in contrast between infarcted and noninfarcted myocardium. Eight dogs underwent coronary occlusion; their hearts were removed 6 hours later. Estimates of T2 for normal and infarcted myocardium were derived from MR images. Infarct size was quantified anatomically using triphenyltetrazolium-chloride (TTC) staining and compared with MR estimates. The T2 values derived from the images clearly discriminated between infarcted (126 +/- 22 msec) and normal myocardium (88 +/- 10 msec, P less than .05), providing images with good contrast between normal and infarcted myocardium. Comparable differences in T2 values were also noted from spectrometric determinations. Estimates of infarct size by MR imaging compared well with TTC estimates (r = 0.98) over a wide range of infarct sizes from 3% to 29% of the left ventricular mass. These results suggest the potential for in vivo quantification of infarct size based on the inherent contrast difference between infarcted and normal myocardium. 相似文献
75.
76.
Costa DO Alves AT Calasans-Maia MD Cruz RL Lourenço Sde Q 《Brazilian dental journal》2011,22(2):171-174
Ameloblastic fibroma is a relatively rare benign odontogenic tumor in which both the epithelial and ectomesenchymal components are neoplastic. An 8-year-old Caucasian boy was referred to the dentist for evaluation of failed eruption of the maxillary left first molar. The panoramic radiograph showed a well-circumscribed unilocular radiolucency involving an unerupted maxillary left first permanent molar. The lesion was enucleated and the material was sent for histopathologic examination. Microscopically, it was composed by cords and islands of odontogenic epithelium in a myxoid cell-rich stroma that closely resemble the dental papilla with histopathological diagnosis of ameloblastic fibroma. After 24 months of follow-up no recurrence was observed and the maxillary left first molar erupted spontaneously through the buccal mucosa and was aligned with a fixed orthodontic appliance. This case emphasized the importance of careful differential diagnosis of intraosseous oral lesions and reported a rarity of the lesion and its atypical location. 相似文献
77.
A dot-screen pattern was devised and superimposed on computed tomography images to improve contrast at a viewbox. The phenomenon is believed to be probably related to lateral inhibition. To evaluate its usefulness, the device was used on 12 images (eight showed metastatic liver lesions, and four were normal); each image was viewed without the device by ten observers. Three control images were viewed a second time without the device. The remaining nine images were viewed a second time with the device. The overlay improved diagnostic performance in nine observers. Sensitivity improved by 12%, and confidence in true-positive findings increased by 41.6%. Forty-five percent of false-negative findings were converted to true positive with the use of the overlay. 相似文献
78.
Aránzazu Caballero-Marcos Magdalena Salcedo Roberto Alonso-Fernández Manuel Rodríguez-Perálvarez María Olmedo Javier Graus Morales Valentín Cuervas-Mons Alba Cachero Carmelo Loinaz-Segurola Mercedes Iñarrairaegui Lluís Castells Sonia Pascual Carmen Vinaixa-Aunés Rocío González-Grande Alejandra Otero Santiago Tomé Javier Tejedor-Tejada José María Álamo-Martínez Luisa González-Diéguez Flor Nogueras-Lopez Gerardo Blanco-Fernández Gema Muñoz-Bartolo Francisco Javier Bustamante Emilio Fábrega Mario Romero-Cristóbal Rosa Martin-Mateos Julia Del Rio-Izquierdo Ana Arias-Milla Laura Calatayud Alberto A. Marcacuzco-Quinto Víctor Fernández-Alonso Concepción Gómez-Gavara Jordi Colmenero Patricia Muñoz José A. Pons the Spanish Society of Liver Transplantation 《American journal of transplantation》2021,21(8):2876-2884
The protective capacity and duration of humoral immunity after SARS-CoV-2 infection are not yet understood in solid organ transplant recipients. A prospective multicenter study was performed to evaluate the persistence of anti-nucleocapsid IgG antibodies in liver transplant recipients 6 months after coronavirus disease 2019 (COVID-19) resolution. A total of 71 liver transplant recipients were matched with 71 immunocompetent controls by a propensity score including variables with a well-known prognostic impact in COVID-19. Paired case–control serological data were also available in 62 liver transplant patients and 62 controls at month 3 after COVID-19. Liver transplant recipients showed a lower incidence of anti-nucleocapsid IgG antibodies at 3 months (77.4% vs. 100%, p < .001) and at 6 months (63.4% vs. 90.1%, p < .001). Lower levels of antibodies were also observed in liver transplant patients at 3 (p = .001) and 6 months (p < .001) after COVID-19. In transplant patients, female gender (OR = 13.49, 95% CI: 2.17–83.8), a longer interval since transplantation (OR = 1.19, 95% CI: 1.03–1.36), and therapy with renin–angiotensin–aldosterone system inhibitors (OR = 7.11, 95% CI: 1.47–34.50) were independently associated with persistence of antibodies beyond 6 months after COVID-19. Therefore, as compared with immunocompetent patients, liver transplant recipients show a lower prevalence of anti-SARS-CoV-2 antibodies and more pronounced antibody levels decline. 相似文献
79.
Zaeem Lone Prithvi B. Murthy JJ Haijing Zhang Kyle J. Ericson Lewis Thomas Abhinav Khanna Georges-Pascal Haber Byron H. Lee 《Urologic oncology》2021,39(5):301.e1-301.e9
PurposeRenal function outcomes following robot-assisted radical cystectomy (RARC) have not been well established. We sought to compare long-term renal function outcomes between open radical cystectomy, RARC with extracorporeal urinary diversion and intracorporeal urinary diversion at a high volume institution.Materials and MethodsWe retrospectively reviewed our institutional bladder cancer database for patients who underwent RC from 2010 to 2019 with pre-operative estimated glomerular filtration rate (eGFR) > 45 ml/min/1.73m2. Changes in renal function were assessed through locally weighted scatter plot smoothing and comparison of median eGFR between surgical groups. Chronic Kidney Disease Stage 3B was defined as eGFR < 45 ml/min/1.73m2. Renal function decline was defined as a ≥10 ml/min/1.73m2 drop in eGFR. Kaplan Meier method with log-rank was used to compare CKD 3B-free survival and renal function decline. Cox Proportional Hazards model was used to identify predictors of CKD 3B.ResultsSix hundred and forty four patients were included with median follow-up of 32 months (IQR 12–56). Preoperative characteristics were similar among the groups with no differences in median pre-operative eGFR (ORC: 74.6, extracorporeal urinary diversion: 74.3, intracorporeal urinary diversion: 71.6 ml/min/1.73m2, P = 0.15). Median postoperative eGFR on follow up was not different between groups (P = 0.56). 33% of patients developed CKD 3B. There were no differences in CKD 3B-free survival by surgical approach (P = 0.23) or urinary diversion (P = 0.09). 64% of patients experienced renal function decline with a median time of 2.4 years (P 0.23). Predictors of CKD were pathologic T3 disease or greater (HR: 1.77, P = 0.01), ureteroenteric anastomotic stricture (HR: 2.80, P < 0.001), preoperative CKD Stage 2 (HR: 1.81, P =0.02), and preoperative CKD Stage 3A (HR: 5.56, P < 0.001).ConclusionRenal function decline is common after RC. Tumor stage, pre-operative eGFR, and ureteral stricture development, not surgical approach, influence renal function decline. 相似文献