全文获取类型
收费全文 | 1712259篇 |
免费 | 119090篇 |
国内免费 | 3427篇 |
专业分类
耳鼻咽喉 | 24298篇 |
儿科学 | 49910篇 |
妇产科学 | 46477篇 |
基础医学 | 242349篇 |
口腔科学 | 50010篇 |
临床医学 | 145670篇 |
内科学 | 340024篇 |
皮肤病学 | 35972篇 |
神经病学 | 134130篇 |
特种医学 | 68149篇 |
外国民族医学 | 411篇 |
外科学 | 274391篇 |
综合类 | 34715篇 |
现状与发展 | 1篇 |
一般理论 | 469篇 |
预防医学 | 119134篇 |
眼科学 | 39204篇 |
药学 | 127393篇 |
3篇 | |
中国医学 | 3671篇 |
肿瘤学 | 98395篇 |
出版年
2018年 | 16628篇 |
2017年 | 13104篇 |
2016年 | 14247篇 |
2015年 | 16211篇 |
2014年 | 22597篇 |
2013年 | 34203篇 |
2012年 | 46178篇 |
2011年 | 48695篇 |
2010年 | 29245篇 |
2009年 | 28016篇 |
2008年 | 47374篇 |
2007年 | 49780篇 |
2006年 | 50720篇 |
2005年 | 49339篇 |
2004年 | 47493篇 |
2003年 | 45821篇 |
2002年 | 45044篇 |
2001年 | 88310篇 |
2000年 | 91175篇 |
1999年 | 76768篇 |
1998年 | 19383篇 |
1997年 | 17429篇 |
1996年 | 17384篇 |
1995年 | 16202篇 |
1994年 | 15306篇 |
1993年 | 14189篇 |
1992年 | 59095篇 |
1991年 | 56627篇 |
1990年 | 55007篇 |
1989年 | 53368篇 |
1988年 | 48952篇 |
1987年 | 48076篇 |
1986年 | 45324篇 |
1985年 | 43280篇 |
1984年 | 31517篇 |
1983年 | 26774篇 |
1982年 | 14920篇 |
1981年 | 13052篇 |
1979年 | 28585篇 |
1978年 | 19617篇 |
1977年 | 16708篇 |
1976年 | 15113篇 |
1975年 | 16658篇 |
1974年 | 20103篇 |
1973年 | 19032篇 |
1972年 | 18105篇 |
1971年 | 16901篇 |
1970年 | 16260篇 |
1969年 | 15238篇 |
1968年 | 14179篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
995.
996.
A. Varkey N. C. Tan R. Girotto W. C. Tang Y. T. Liu H. C. Chen 《ANZ journal of surgery》2007,77(Z1):A62-A62
Purpose Post operative monitoring is crucial for the success of microsurgical free tissue transfer. Sophisticated and expensive methods are available for monitoring. We propose a novel technique using digital photography and the internet as a reliable and cost effective method to monitor free tissue transfers. Methods 163 micro‐vascular procedures were monitored using this technique over 8 months. Serial photographs taken to show flap color. Capillary refill time, pin prick‐ bleed time and color and hand held Doppler signal was recorded in the movie mode of a standard 5 mega pixel camera with duration of 15 seconds. Data was sent to the surgeon at regular intervals and or as deemed necessary. Results Analysis of the 67 cases is presented. 5 re‐explorations were done. The early diagnosis of venous congestion was possible using this technique. Timely intervention contributed to the success of the re‐explorations and these flaps could be salvaged. The file size of images was in the range of 1 MB–6 MB. The file size of an entire set of images ranged about 7 MB–9 MB. These were sent across the ADSL internet lines. Conclusion The use of the digital images and the internet allow reconstructive surgeons to have a reliable picture of the state of their free tissue transfers. This permits decrease in observer error and saves valuable time which otherwise needs to be spent to verify situations of doubt and offers an ideal solution to the logistic problem of having to visit the patient in case of doubt. 相似文献
997.
Primary squamous cell carcinoma is an extremely rare tumour of the thyroid gland. A case of an elderly lady who was diagnosed to have primary squamous cell carcinoma of the thyroid gland is presented and the role of radiotherapy is discussed. 相似文献
998.
Marilyn Hravnak Leslie A Hoffman Melissa I Saul Thomas G Zullo Julie F Cuneo Ronald V Pellegrini 《American journal of critical care》2004,13(6):499-507; discussion 508
BACKGROUND: Studies suggest that patients who undergo off-pump coronary artery bypass grafting (OPCABG) have fewer short-term complications and use fewer inpatient resources than do patients who undergo standard coronary artery bypass grafting (CABG) with extracorporeal circulation. However, dissimilarity between groups in risk factors for complications has hindered interpretation of results. OBJECTIVES: To compare the prevalence of selected complications (atrial fibrillation, stroke, reoperation, and bleeding) and inpatient resource utilization (length of stay, discharge disposition, total charges) between subjects undergoing primary isolated CABG or OPCABG who were matched with respect to key risk factors. METHODS: Retrospective, causal-comparative survey conducted in 1 center for 18 months. Patients who underwent primary isolated CABG or OPCABG were matched for sex, age (within 2 years), left ventricular ejection fraction (within 0.05), and graft-patient ratio (exact match) and compared for prevalence of new-onset atrial fibrillation, stroke, reoperation within 24 hours, and bleeding. Statistical analysis included Wilcoxon and t tests for paired comparisons. RESULTS: The sample (107 matched pairs) was 63% male, with a mean age of 66 (SD 9.5) years, a mean left ventricular ejection fraction of 0.51 (SD 0.13), and a mean graft-patient ratio of 3.41 (SD 0.74). The 2 groups did not differ significantly in New York Heart Association class (P = .43), Acute Physiology and Chronic Health Evaluation III score (P = .22), postoperative beta-blocker use (P = .73), or comorbid conditions. None of the complications examined differed significantly between pairs. CONCLUSION: Patients with comparable risk profiles have similar prevalences of selected complications after CABG and OPCABG. 相似文献
999.
Eser Tüfek?i Thomas E Merrill Maria R Pintado John P Beyer William A Brantley 《American journal of orthodontics and dentofacial orthopedics》2004,125(6):733-739
Teeth with white spot lesions (WSL) might be more prone to enamel loss during bracket debonding. This in vitro study compared enamel loss from teeth with (n = 14) and without (n = 14) WSL after polishing with low-speed finishing burs or disks (Sof-Lex, 3M ESPE, St Paul, Minn). Debonded surfaces were analyzed with a contact stylus profilometer, and digitized data were compared with baseline readings by using AnSur NT software (Regents, University of Minnesota, Minneapolis, Minn). Specimen surfaces were also examined with a scanning electron microscope. Two-way analysis of variance was performed to analyze the data. In teeth without WSL, the volume losses were 0.16 mm(3) for the bur group and 0.10 mm(3) for the disk group; the mean maximum depths were 47.7 microm for the bur group and 54.3 microm for the disk group. In teeth with WSL, the volume losses were 0.06 and 0.17 mm(3), and the mean maximum depths were 35.1 and 48.7 microm for the bur and disk groups, respectively. There were no significant differences in enamel loss between the 2 groups of teeth without WSL (P =.12). However, in teeth with WSL, the burs removed less enamel than the disks (P = 0.006). Scanning electron microscope examination showed that any damage on the enamel surface was usually located in the cervical third of the teeth. On most specimens, even though tooth surfaces appeared resin-free to the naked eye, there were remnants of it. The differences between groups were so small that they might be clinically insignificant. 相似文献
1000.
Z D Daniil E Zintzaras T Kiropoulos A I Papaioannou A Koutsokera A Kastanis K I Gourgoulianis 《The European respiratory journal》2007,30(5):957-964
Pleural effusion is a common complication of various diseases. Conventional methods are not always capable of establishing the cause of pleural effusion, so alternative tests are needed. The aim of this study was to explore means of discriminating between different pleural effusion groups, malignant, parapneumonic and tuberculous, based on the combined function of seven biological markers. Adenosine deaminase (ADA), interferon-gamma, C-reactive protein (CRP), carcinoembryonic antigen, interleukin-6, tumour necrosis factor-alpha and vascular endothelial growth factor concentration levels were measured in pleural fluid from 45 patients with malignant, 15 with parapneumonic and 12 with tuberculous pleural effusion. Receiver operating characteristic curve analysis, multinomial logit modelling and canonical variate analysis were applied to discriminate the pleural effusion groups. The three groups could be discriminated successfully using the measured markers. The most important parameters for discrimination were ADA and CRP concentration levels. An individual with an ADA concentration level of >45 U.L(-1) and a CRP concentration of <4 mg.dL(-1) was more likely to belong to the tuberculous pleural effusion group, whereas one with an ADA concentration level of <40 U.L(-1) and a CRP concentration of >6 mg.dL(-1) was more likely to belong to the parapneumonic pleural effusion group, and one with a CRP concentration of <4 mg.dL(-1) to the malignant pleural effusion group. The combination of adenosine deaminase and C-reactive protein levels might be sufficient for discriminating between the three different groups of exudative pleural effusion: malignant, tuberculous and parapneumonic. 相似文献