全文获取类型
收费全文 | 36587篇 |
免费 | 2783篇 |
国内免费 | 426篇 |
专业分类
耳鼻咽喉 | 392篇 |
儿科学 | 1011篇 |
妇产科学 | 967篇 |
基础医学 | 4624篇 |
口腔科学 | 597篇 |
临床医学 | 3838篇 |
内科学 | 7834篇 |
皮肤病学 | 865篇 |
神经病学 | 2437篇 |
特种医学 | 1421篇 |
外科学 | 4917篇 |
综合类 | 1200篇 |
一般理论 | 32篇 |
预防医学 | 2003篇 |
眼科学 | 1605篇 |
药学 | 2752篇 |
中国医学 | 310篇 |
肿瘤学 | 2991篇 |
出版年
2023年 | 270篇 |
2022年 | 512篇 |
2021年 | 959篇 |
2020年 | 619篇 |
2019年 | 788篇 |
2018年 | 1004篇 |
2017年 | 766篇 |
2016年 | 877篇 |
2015年 | 1055篇 |
2014年 | 1388篇 |
2013年 | 1651篇 |
2012年 | 2354篇 |
2011年 | 2468篇 |
2010年 | 1433篇 |
2009年 | 1282篇 |
2008年 | 1926篇 |
2007年 | 2037篇 |
2006年 | 2009篇 |
2005年 | 1945篇 |
2004年 | 1709篇 |
2003年 | 1594篇 |
2002年 | 1426篇 |
2001年 | 1137篇 |
2000年 | 1071篇 |
1999年 | 913篇 |
1998年 | 437篇 |
1997年 | 332篇 |
1996年 | 299篇 |
1995年 | 245篇 |
1994年 | 231篇 |
1993年 | 231篇 |
1992年 | 473篇 |
1991年 | 454篇 |
1990年 | 441篇 |
1989年 | 428篇 |
1988年 | 380篇 |
1987年 | 392篇 |
1986年 | 341篇 |
1985年 | 294篇 |
1984年 | 221篇 |
1983年 | 157篇 |
1982年 | 111篇 |
1981年 | 94篇 |
1980年 | 102篇 |
1979年 | 143篇 |
1978年 | 95篇 |
1977年 | 88篇 |
1976年 | 89篇 |
1975年 | 90篇 |
1972年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Bibhuti B Das Linda B Pauliks Ole A Knudson Scott Kirby Kak-Chen Chan Lilliam Valdes-Cruz Raul O Cayre 《Journal of the American Society of Echocardiography》2005,18(3):231-236
We identified 18 patients with double-orifice mitral valve (DOMV) and intact atrioventricular (AV) septum out of 40,179 echocardiographic studies performed between 1997 and 2002 at Children's Hospital, Denver, CO. In this study we describe (1) the anatomic characteristics of the DOMV in the absence of AV septal defect, (2) the function of the mitral valve by spectral and color Doppler flow mapping, and (3) associated lesions. The topographic location of the orifices in the leaflets suggests possible embryologic mechanisms of DOMV. In this series, DOMV was most commonly associated with left-sided obstructive lesions (in 39% of patients). Spectral and color Doppler interrogation demonstrated a normal flow profile in most cases; only 2 patients had significant mitral regurgitation or stenosis. Therefore, due to the uncertain natural history of this lesion and the potential need for endocarditis prophylaxis, careful imaging of the mitral valve is recommended, particularly in the presence of left-sided obstructive lesions. 相似文献
52.
This study examines how acute hand injuries affect patients in their roles as spouse, caregiver, and/or worker. Qualitative data from patient interviews were used to analyze how these life roles were affected by the individuals' hand injuries. Data were extracted from interviews of three hand patients who had one or more roles of spouse, caregiver, and/or worker affected by their injury. Data were then examined and categorized for each life role by participant. Participants' views of how hand therapy affected their recovery and resumption of occupational role performance were also examined. Results showed that the participants expressed profound degrees of change in their ability to perform satisfactorily in their various life roles. 相似文献
53.
BACKGROUND: Increased autoantibody prevalence has been described in instances of high-dose exposure to polychlorinated biphenyls (PCBs). In 1996, an equipment malfunction at the Swan Hills Treatment Centre in Alberta, Canada, caused the release of gases containing PCBs into the ambient air. In view of the immune effects of PCBs and their potential as endocrine disruptors, we assessed autoantibody prevalence and looked for correlations with PCB levels. METHODS: Fifty-seven persons living within a 100 km radius of the waste treatment facility were assessed. Autoantibodies were measured by indirect immunofluorescence, double immunodiffusion, and immunoblotting. The levels of 26 congeners of PCBs were measured by gas chromatography and mass spectrometry. Provincial health records for physician visits and hospitalizations were reviewed for diagnoses of autoimmune disease. RESULTS: The prevalence of autoantibodies was 11% in the study participants and 0% in healthy controls. There was no correlation of PCB levels with autoantibody results. There was no associated increase in autoimmune disease noted on physician visits or hospitalizations. PCB levels were comparable to background levels reported for other populations. CONCLUSION: A correlation of titers of autoantibodies in the sera of individuals at risk and the blood levels of PCBs was not found, and the prevalence of autoantibodies in the at-risk group was not statistically different (p > .05) from that of an unexposed control group. The study group had higher titers of autoantibodies and some strong reactivity with intracellular antigens, but the significance of this observation may be understood only after long-term clinical assessments and follow-up. 相似文献
54.
Feng-Yuan Liu Chien-Yu Lin Joseph T Chang Shu-Hang Ng Shy-Chyi Chin Hung-Ming Wang Chun-Ta Liao Sheng-Chieh Chan Tzu-Chen Yen 《Journal of nuclear medicine》2007,48(10):1614-1619
Conventional work-up (CWU) with chest radiography, abdominal ultrasonography, and skeletal scintigraphy has limited value in M staging of nonkeratinizing nasopharyngeal carcinoma (NPC). Our aim was to evaluate whether (18)F-FDG PET could replace CWU by comparing their diagnostic efficacies. METHODS: Patients with histologically proven nonkeratinizing NPC and no prior treatment were prospectively enrolled. All study participants underwent CWU and (18)F-FDG PET for primary M staging. Distant metastasis was considered to be present if there was any reliable evidence identified within 1 y after diagnosis. The comparative diagnostic efficacies of (18)F-FDG PET, CWU, and the combination of (18)F-FDG PET and CWU (PET+CWU) were evaluated using the areas under the receiver-operating-characteristic (ROC) curves. RESULTS: Sixty-one (20.3%) of 300 eligible patients were found to have distant metastases. On a patient-based analysis, (18)F-FDG PET was found to be more effective than CWU (P < 0.001), whereas it was equally effective with PET+CWU (P = 0.130). On region-based analyses, (18)F-FDG PET was more effective than skeletal scintigraphy and chest radiography for detecting bone metastases (P < 0.001) and chest metastases (P < 0.001), respectively. (18)F-FDG PET and abdominal ultrasound were equally effective for detecting hepatic metastases (P = 0.127). On region-based analyses, the combination of (18)F-FDG PET and CWU did not yield any noticeable increase in diagnostic efficacy. CONCLUSION: (18)F-FDG PET can replace CWU in primary M staging of nonkeratinizing NPC. 相似文献
55.
56.
57.
Cheuk‐Kin Lo Colin S.H. Chu Tong Zhu Chan‐Chung Ma Kai‐Ming Ko Kwok‐Keung Ho 《Surgical Practice》2007,11(4):147-153
Aim: The prognosis of patients with disseminated colorectal carcinoma is poor except for those with single organ pulmonary or hepatic metastases. The objective of the present study was to evaluate the result of pulmonary metastasectomy for colorectal secondary and to identify the prognostic factors. Methods: This was a retrospective study of 80 patients who had pulmonary metastasectomy for pulmonary secondary from colorectal carcinoma in Queen Elizabeth Hospital, Hong Kong. Results: The overall 5‐year and 10‐year survival rates of the entire cohort were 42.5% and 35.5%, respectively. High premetastasectomy carcinoembryonic antigen (> 20 μg/dL), short disease‐free interval (< 12 months) and incomplete resection were the independent prognostic factors. Neither the characteristics of the primary colorectal tumour nor the number of metastatic nodules had a significant contribution to the long‐term survival. Six patients underwent second pulmonary metastasectomy and three were still free from tumour recurrence after the second operation. Conclusion: Patients with pulmonary metastases from colorectal carcinoma would benefit from pulmonary metastasectomy. High premetastasectomy carcinoembryonic antigen and short disease‐free interval were negative predictive factors for survival. Long‐term follow‐up study is required, as recurrence can occur more than 5 years after pulmonary metastasectomy. Also, whether the survival benefit is due to surgical treatment effect or lead‐time bias remains undecided. 相似文献
58.
Man-Hong Jim Hee-Hwa Ho Annie On-On Chan Wing-Hing Chow 《Catheterization and cardiovascular interventions》2007,69(7):969-975
BACKGROUND: Sleeve technique is a modified version of crush technique. It is specifically designed to increase the success rate of final kissing balloon inflation, which used to be a major limitation of the latter. OBJECTIVES: The aim of this study was to examine the feasibility, safety, and early clinical outcomes of sleeve technique in stenting different types (de novo, in-stent restenotic or in-stent bifurcation) of coronary bifurcation lesions at different locations. METHODS: From August 2005 to May 2006, 41 consecutive patients with symptomatic, nonleft-main coronary bifurcation stenoses of diameter narrowing >or=50% were treated with two-stent strategy, using sleeve technique. RESULTS: The mean age was 63.6 +/- 11.6 years with male predominance (70.7%). High prevalence of diabetes mellitus (31.7%), total occlusion (22.0%), and multi-vessel disease (65.9%) was observed in this cohort. Intravenous abciximab was given in 35 (85.4%) patients. Final kissing balloon inflation was successfully performed in all patients. The minimal luminal diameter in main vessel and side branch was increased from 0.97 +/- 0.53 mm and 0.81 +/- 0.45 mm to 2.76 +/- 0.34 mm and 2.22 +/- 0.35 mm, respectively. The mean procedure time was only 66.6 +/- 24.6 min. There was one (2.4%) case of subacute stent thrombosis presented as non-Q-wave myocardial infarction at day 3 postprocedure. The resultant in-hospital and 30-day major adverse cardiac event rate were both 2.4%. CONCLUSIONS: Sleeve technique is a feasible and efficient approach in stenting of coronary bifurcation stenoses. 相似文献
59.
Twelve years'' experience of computer-aided diagnosis in a district general hospital. 总被引:2,自引:0,他引:2
下载免费PDF全文
![点击此处可从《Annals of the Royal College of Surgeons of England》网站下载免费的PDF全文](/ch/ext_images/free.gif)
W. A. McAdam B. M. Brock T. Armitage P. Davenport M. Chan F. T. de Dombal 《Annals of the Royal College of Surgeons of England》1990,72(2):140-146
This paper describes experience in a modern district general hospital with a small desktop system for computer-aided diagnosis of acute abdominal pain, over a 12-year period involving 5512 cases. When compared with a baseline year (1973) in which unaided performance was monitored, during an initial study period (1974-76) the diagnostic accuracy of junior staff rose by between 10 and 15%. This higher performance level was then maintained for a decade (1976-86) despite changes in staff. The perforation rate among appendicitis cases fell from 27% to 12.5%, accompanied by a smaller fall in negative laparotomy rates. The saving in surgical bednights devoted to acute abdominal pain was approximately 15%, and the notional cost of resources saved during the first 6 years of operation was 120,000 pounds. Other hospitals have shown--in the short term--benefits similar to those obtained at Airedale District General Hospital. The long-term benefits of the system at Airedale reinforce the conclusions of the earlier short-term trials that a comparable system should probably be offered to all DGHs in the UK, not as an exercise in 'artificial intelligence' but as an effective continuing stimulus to good clinical practice. 相似文献
60.