全文获取类型
收费全文 | 755668篇 |
免费 | 51738篇 |
国内免费 | 1682篇 |
专业分类
耳鼻咽喉 | 9581篇 |
儿科学 | 23078篇 |
妇产科学 | 17978篇 |
基础医学 | 116794篇 |
口腔科学 | 18945篇 |
临床医学 | 68945篇 |
内科学 | 145126篇 |
皮肤病学 | 15462篇 |
神经病学 | 59620篇 |
特种医学 | 26596篇 |
外国民族医学 | 74篇 |
外科学 | 113950篇 |
综合类 | 11843篇 |
一般理论 | 432篇 |
预防医学 | 59746篇 |
眼科学 | 18482篇 |
药学 | 56908篇 |
5篇 | |
中国医学 | 1314篇 |
肿瘤学 | 44209篇 |
出版年
2021年 | 8284篇 |
2019年 | 8504篇 |
2018年 | 10663篇 |
2017年 | 7932篇 |
2016年 | 8846篇 |
2015年 | 10119篇 |
2014年 | 14390篇 |
2013年 | 20973篇 |
2012年 | 30237篇 |
2011年 | 32472篇 |
2010年 | 18542篇 |
2009年 | 16887篇 |
2008年 | 29745篇 |
2007年 | 31603篇 |
2006年 | 31660篇 |
2005年 | 31054篇 |
2004年 | 29647篇 |
2003年 | 27920篇 |
2002年 | 26867篇 |
2001年 | 26108篇 |
2000年 | 26618篇 |
1999年 | 22806篇 |
1998年 | 8420篇 |
1997年 | 7184篇 |
1996年 | 7162篇 |
1995年 | 6665篇 |
1994年 | 6014篇 |
1992年 | 16957篇 |
1991年 | 17422篇 |
1990年 | 17403篇 |
1989年 | 16745篇 |
1988年 | 15508篇 |
1987年 | 15356篇 |
1986年 | 14522篇 |
1985年 | 13919篇 |
1984年 | 10818篇 |
1983年 | 9347篇 |
1982年 | 5880篇 |
1979年 | 10102篇 |
1978年 | 7581篇 |
1977年 | 6387篇 |
1976年 | 6171篇 |
1975年 | 6858篇 |
1974年 | 8102篇 |
1973年 | 7525篇 |
1972年 | 7307篇 |
1971年 | 6953篇 |
1970年 | 6409篇 |
1969年 | 6062篇 |
1968年 | 5698篇 |
排序方式: 共有10000条查询结果,搜索用时 703 毫秒
941.
942.
A CT-free, intra-operative planning and navigation system for minimally invasive anterior spinal surgery - an accuracy study. 总被引:1,自引:0,他引:1
B Maier G Zheng C Ploss X Zhang K Welle L-P Nolte I Marzi 《Computer aided surgery》2007,12(4):233-241
OBJECTIVE: A comprehensive study was performed to evaluate the accuracy of a newly developed CT-free, intra-operative planning and navigation system for anterior spine surgery. MATERIALS AND METHODS: Instruments and an image intensifier were tracked using the SurgiGATE navigation system. A laboratory study was performed on 27 plastic vertebrae. Fiducial markers were implanted in the vertebrae for accuracy evaluation purposes, and a dynamic reference base was placed on the vertebrae to establish a patient coordinate system (P-COS). Two fluoroscopic images were used for intra-operative planning. The graft bed plan was recorded in P-COS, followed by surgical formation of the graft bed, which was visualized. To evaluate the accuracy, the vertebrae were scanned with CT, and the markers were used to calculate an accurate paired-point registered transformation between the CT coordinate system and P-COS. RESULTS: Using the new SPO module, accurate planning and navigation of a resection of the vertebral body is possible using two fluoroscopic images. The overall mean error between the planned resection volume and the actual resection was 0.98 mm. In addition, the module can serve as an educational tool for training spine surgeons. CONCLUSIONS: The new fluoroscopy-based system can be used safely for accurate performance of anterior resection during spondylodesis. New methods for safe and accurate registration during anterior spine surgery need to be developed. 相似文献
943.
944.
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
945.
Kristin Mekeel David Mulligan Kunam Sudhakar Reddy Adyr Moss Kristi Harold 《Liver transplantation》2007,13(11):1576-1581
Incisional hernias occur in up to 17% of patients after liver transplantation. Laparoscopic ventral hernia repair is associated with fewer wound complications and a decreased incidence of recurrence when compared to open hernia repair in nontransplant patients. This is a retrospective review of 13 patients who underwent laparoscopic incisional hernia repair (LAP group) after liver transplantation compared to 14 patients who had open repairs (OP group; all but one with mesh). Primary immunosuppression in both groups at the time of transplantation was tacrolimus, but more patients in the LAP group were on sirolimus at the time of hernia, while more patients in the OP group were on prednisone at the time of hernia repair. All operations were completed with a laparoscopic approach; there were no conversions to open. Length of stay differed significantly between the 2 groups, with a mean of 5.4 days for the LAP group compared to 2.7 days in the OP group (0.0059). Complications occurred in 2 (15%) of the patients in the LAP group and 5 (36%) in the OP group. One patient in the LAP group required mesh removal to exclude causes of recurrent ascites, and 1 in the OP group for mesh infection. One (7.6%) of the patients in the LAP group developed a recurrence, compared to 29% (4) of the OP group (P =0.3259). In conclusion, laparoscopic incisional hernia repair is safe in patients after liver transplantation, with a low risk of infection or recurrence. 相似文献
946.
947.
Oral Valganciclovir Is Noninferior to Intravenous Ganciclovir for the Treatment of Cytomegalovirus Disease in Solid Organ Transplant Recipients 总被引:1,自引:0,他引:1
A. Åsberg A. Humar H. Rollag A. G. Jardine H. Mouas M. D. Pescovitz D. Sgarabotto M. Tuncer I. L. Noronha A. Hartmann 《American journal of transplantation》2007,7(9):2106-2113
Intravenous ganciclovir is the standard treatment for cytomegalovirus disease in solid organ transplant recipients. Oral valganciclovir is a more convenient alternative. In a randomized, international trial, recipients with cytomegalovirus disease were treated with either 900 mg oral valganciclovir or 5 mg/kg i.v. ganciclovir twice daily for 21 days, followed by 900 mg daily valganciclovir for 28 days. A total of 321 patients were evaluated (valganciclovir [n = 164]; i.v. ganciclovir [n = 157]). The success rate of viremia eradication at Day 21 was 45.1% for valganciclovir and 48.4% for ganciclovir (95% CI -14.0% to +8.0%), and at Day 49; 67.1% and 70.1%, respectively (p = NS). Treatment success, as assessed by investigators, was 77.4% versus 80.3% at Day 21 and 85.4% versus 84.1% at Day 49 (p = NS). Baseline viral loads were not different between groups and decreased exponentially with similar half-lives and median time to eradication (21 vs. 19 days, p = 0.076). Side-effects and discontinuations of assigned treatment (18 of 321 patients) were comparable. Oral valganciclovir shows comparable safety and is not inferior to i.v. ganciclovir for treatment of cytomegalovirus disease in organ transplant recipients and provides a simpler treatment strategy, but care should be taken in extrapolating to organ transplant recipients not properly represented in the present study. 相似文献
948.
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
949.
To date, the main respiratory health consequence from the collapse of the World Trade Center (WTC) on September 11, 2001 has been the “WTC Cough Syndrome” (chronic rhinosinusitis, asthma, and/or bronchitis, often complicated by gastroesophageal reflux dysfunction). Syndrome incidence and severity have been linked to WTC dust exposure intensity. While it is too early to ascertain long-term effects of WTC dust exposure, effective treatment guidelines have been designed through a collaborative effort by the three established centers of excellence for WTC medical monitoring and treatment and the WTC Registry. These treatment recommendations are described here.
相似文献950.
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