全文获取类型
收费全文 | 2203篇 |
免费 | 130篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 72篇 |
妇产科学 | 41篇 |
基础医学 | 322篇 |
口腔科学 | 23篇 |
临床医学 | 286篇 |
内科学 | 529篇 |
皮肤病学 | 70篇 |
神经病学 | 202篇 |
特种医学 | 60篇 |
外科学 | 193篇 |
综合类 | 15篇 |
一般理论 | 1篇 |
预防医学 | 192篇 |
眼科学 | 21篇 |
药学 | 137篇 |
中国医学 | 8篇 |
肿瘤学 | 142篇 |
出版年
2023年 | 17篇 |
2022年 | 36篇 |
2021年 | 51篇 |
2020年 | 41篇 |
2019年 | 56篇 |
2018年 | 45篇 |
2017年 | 29篇 |
2016年 | 46篇 |
2015年 | 46篇 |
2014年 | 74篇 |
2013年 | 111篇 |
2012年 | 146篇 |
2011年 | 116篇 |
2010年 | 83篇 |
2009年 | 81篇 |
2008年 | 153篇 |
2007年 | 155篇 |
2006年 | 157篇 |
2005年 | 133篇 |
2004年 | 101篇 |
2003年 | 124篇 |
2002年 | 108篇 |
2001年 | 37篇 |
2000年 | 19篇 |
1999年 | 20篇 |
1998年 | 25篇 |
1997年 | 23篇 |
1996年 | 13篇 |
1995年 | 15篇 |
1994年 | 16篇 |
1993年 | 16篇 |
1992年 | 18篇 |
1991年 | 13篇 |
1990年 | 15篇 |
1989年 | 18篇 |
1988年 | 19篇 |
1987年 | 19篇 |
1986年 | 17篇 |
1985年 | 11篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 10篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 11篇 |
1977年 | 4篇 |
1973年 | 4篇 |
1969年 | 6篇 |
1968年 | 7篇 |
1966年 | 4篇 |
排序方式: 共有2345条查询结果,搜索用时 15 毫秒
1.
BackgroundEpidemiological studies on peptic ulcer disease (PUD) have shown a recent decrease in hospital admissions in Western countries.ObjectiveThis paper aimed to study the current status and risk factors of PUD in a Nigerian metropolis.MethodsA cross-sectional study of symptomatic patients at upper gastrointestinal (GI) endoscopy diagnosed with PUD from February 2014 to September 2019 at a referral endoscopy facility in Port Harcourt, Niger delta region of Nigeria. The variables studied included demographics, symptoms and duration, blood group, chronic non-steroidal anti-inflammatory (NSAID) use, smoking, endoscopic and histology findings. Statistical analysis was performed using SPSS version 20.ResultsA total of 434 upper GI endoscopies were performed during the study period with thirty-one diagnosis of PUD made. The mean age of gastric ulcer (GU) and duodenal ulcer (DU) cases were 54.4 ± 20.2yrs and 48.1 ± 14.5yrs respectively (p = 0.367). GU to DU ratio was 1.4:1. H. pylori infection, chronic NSAID use and blood group O were seen in 7(22.5%), 8(25.8%) and 18(72.0%) respectively. Major indication in 21(67.7%) cases was gastrointestinal bleeding.ConclusionThere is a low diagnostic rate of PUD (6.7%) with pre-pyloric antral gastric ulcers as most common type and multifactorial aetiology. 相似文献
2.
Evaluation of training nurses to perform semi‐automated three‐dimensional left ventricular ejection fraction using a customised workstation‐based training protocol
下载免费PDF全文
![点击此处可从《Journal of clinical nursing》网站下载免费的PDF全文](/ch/ext_images/free.gif)
3.
Nursing in the health care system of the postmodern world: crossroads, paradoxes and complexity 总被引:1,自引:0,他引:1
Ada Spitzer RN PhD 《Journal of advanced nursing》1998,28(1):164-171
Entering the postmodern world in which society is confronting crossroads, paradoxes, and complexity, the health care system is encountering a transformation more comprehensive and revolutionary than has ever been seen before. Analysis of the state of nursing vis a vis these transformations indicates that the current paradigm does not ensure the existence of the profession in the postmodern health care system. That is because of increased difficulties in consolidating the economic and quality issues into the core of nursing, and in understanding the complexity inherent in health related situations. 相似文献
4.
Absence of HIV antigens in renal tissue from patients with HIV-associated nephropathy 总被引:3,自引:0,他引:3
G Barbiano di Belgiojoso A Genderini L Vago C Parravicini S Bertoli N Landriani 《Nephrology, dialysis, transplantation》1990,5(7):489-492
HIV-associated nephropathy (HIV-N) is considered a distinctive disease, the pathogenesis of which is still undefined. Direct virus-induced renal cell damage has been postulated. The numerous cytolytic ultrastructural changes and a few studies by immunoperoxidase support this hypothesis, but there has been no demonstration of virus by electron-microscopy (EM) or by tissue culture. In seven out of 12 cases with histological characteristics of HIV nephropathy, with proteinuria (five cases) or with nephrotic syndrome (two cases), we tested renal tissue for HIV antigens: core p18 and p25; envelope gp45 and gp110, by means of immunoperoxidase avidin-biotin complex monoclonal antibodies (MoAbs). Light-microscopy (LM) showed in five patients a focal and segmental glomerular sclerosis, and in two a mesangial hyperplasia with vacuolisation of visceral epithelium and protein inclusions. Electron-microscopy, performed in five of seven patients, showed several protein inclusions in podocyte cytoplasm, tubuloreticular inclusions in endothelial cell cytoplasm in all cases, nuclear degranulation of tubular cells in four cases and nuclear bodies in two. HIV antigens by MoAbs on renal tissue were negative in all cases, in both glomeruli and tubules. These results do not confirm the presence of HIV proteins in renal tissue of patients with HIV nephropathy. A possible explanation, apart from no direct HIV in the disease, may be the low viral load in tissues, because of the early phases of renal damage in most cases. 相似文献
5.
6.
Simona Ben-Haim Ela Kupzov Ada Tamir Alex Frenkel Ora Israel 《Journal of nuclear cardiology》2006,13(6):791-800
BACKGROUND: Fluorine 18 fluorodeoxyglucose (FDG) uptake may be increased in atherosclerotic plaques in asymptomatic patients. Repeat positron emission tomography (PET)/computed tomography (CT) studies were assessed for changes in patterns of FDG uptake and CT calcifications. METHODS AND RESULTS: Fifty consecutive cancer patients (mean age, 68 +/- 8 years) had repeat PET/CT studies 8 to 26 months apart. PET, CT, and PET/CT images were retrospectively evaluated for vascular wall abnormalities and for interval changes in the thoracic and abdominal aortas, as well as in carotid and iliac arteries, classified as PET+/CT+, PET+/CT-, and PET-/CT+. There were 485 abnormal sites in the first study and 495 in the second. CT calcifications were found in 46 patients (92%) in the first study and in 47 (94%) in the second. Vascular wall FDG uptake was found in both studies in 37 patients (74%). The pattern changed in 57 of 119 PET+ sites (48%) in the second study compared with 15 of 366 PET- sites (4%) (P < .0001). In the second study new PET+ sites were observed in 36 of 111 sites (32%) versus new PET-/CT+ sites in 19 of 384 sites (5%) (P < .0001). CONCLUSIONS: Changes in vascular FDG activity and CT calcifications can be assessed by repeat PET/CT. FDG-avid foci may represent a dynamic process, transient inflammation, whereas CT calcifications may indicate stable atherosclerosis. These preliminary results support the need for further research. 相似文献
7.
8.
Impaired in-vitro proliferation of hemopoietic precursors in HIV-1-infected subjects 总被引:1,自引:0,他引:1
Y Lunardi-Iskandar V Georgoulias A M Bertoli Y Augery-Bourget A Ammar D Vittecoq W Rosenbaum P Meyer C Jasmin 《Leukemia research》1989,13(7):573-581
Patients with acquired immunodeficiency syndrome (AIDS) and persistent lymphadenopathy syndrome (LAS) display significant hematological abnormalities of one or more cell lineages. In order to understand the pathophysiologic mechanisms leading to these abnormalities we studied the proliferation capacity of pluripotent and committed hemopoietic precursors using in-vitro colony assays. Anemia, leukopenia and thrombopenia were relatively frequent findings in HIV-infected subjects irrespectively of the patients' clinical status. The colony growth capacity of AIDS patients' GM-CFU and BFU-E was significantly decreased whereas no GEMM-CFU colonies could be obtained. There was no correlation between the number of BFU-E and GM-CFU colony number and the hemoglobin or the absolute number of polynuclear cells, respectively. The plating efficiency of both committed and pluripotent hematopoietic precursors from HIV infected patients could not be enhanced when additional exogenous recombinant GM-CSF, human interleukin 3 or erythropoietin were added in contrast to normal patients' cells. In addition, the impaired colony growth of these precursors could not be restored after adherent or T-cell depletion or the addition of normal allogenic irradiated adherent or/and T cells. Since this colony growth abnormality was also detected in HIV seropositive asymptomatic subjects our findings strongly suggest that the in-vitro growth of hematopoietic precursors is affected early after HIV-1 infection. 相似文献
9.
Reny De Leeuw Elizangela Bertoli John E Schmidt Charles R Carlson 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2005,99(5):558-568
OBJECTIVE: There is a high comorbidity between symptoms of post-traumatic stress disorder (PTSD) and chronic pain incidence. The objective of this investigation was to determine the prevalence of PTSD symptoms in chronic orofacial pain patients. STUDY DESIGN: The study included 1478 adult patients (mean age 36.4 +/- 12.7 years) with primary diagnoses of masticatory/cervical muscle pain or temporomandibular joint pain. Patients completed a battery of psychometric questionnaires including a screening for PTSD symptoms. The sample was divided into a PTSD-positive group (n=218, 15%) a PTSD-negative group (n=551, 37%), and a no-stressor group (n=709, 48%) according to stressor incidence and symptom severity. RESULTS: The current prevalence of PTSD symptomatology was considerably higher than that reported in surveys from the general population. Patients in the PTSD-positive symptom group reported significantly higher psychological distress, sleep dysfunction, and pain severity compared to patients in the other groups. Psychological distress as measured by the SCL-90-R reached clinically significant levels only in those patients with PTSD symptomatology. CONCLUSIONS: The results of this study performed at a tertiary care center suggest that TMD patients without PTSD symptomatology show low levels of psychological distress, if any. Clinically significant levels of psychological distress are likely indicators for PTSD. PTSD screening should be included as part of a routine psychometric test battery in TMD patients. 相似文献
10.
Effects of captopril on hemodynamics and blood gases in chronic obstructive lung disease with pulmonary hypertension 总被引:2,自引:0,他引:2
L Bertoli S Lo Cicero I Busnardo G Rizzato G Montanari 《Respiration; international review of thoracic diseases》1986,49(4):251-256
The effects of Captopril, an angiotensin-converting enzyme inhibitor, on pulmonary hemodynamics and blood gases were studied in 9 patients with chronic obstructive lung disease (COLD) and pulmonary hypertension (PA-P greater than 20 mm Hg). Hemodynamic data were recorded prior to Captopril administration (50 mg per os) and for the next 60 min. Following Captopril administration, significant reductions in mean pulmonary artery pressure (PA-P) (p less than 0.05), in mean pulmonary wedge pressure (PW-P) (p less than 0.05), and in total pulmonary resistance (TPR) were noted; significant reductions in mean brachial artery pressure (BA-P) and systemic vascular resistance (SVR) were also recorded, while cardiac output, heart rate and blood gas tensions showed no significant changes. Furthermore, the higher the hypoxemia, the greater was the reduction in BA-P (p less than 0.05). We therefore feel that Captopril, when administered to COLD patients with pulmonary hypertension, may protect the pulmonary circulation from hypoxic pulmonary vasoconstriction. 相似文献