全文获取类型
收费全文 | 8864篇 |
免费 | 542篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 150篇 |
儿科学 | 229篇 |
妇产科学 | 168篇 |
基础医学 | 1105篇 |
口腔科学 | 1046篇 |
临床医学 | 543篇 |
内科学 | 1813篇 |
皮肤病学 | 195篇 |
神经病学 | 658篇 |
特种医学 | 180篇 |
外科学 | 1163篇 |
综合类 | 54篇 |
一般理论 | 2篇 |
预防医学 | 884篇 |
眼科学 | 282篇 |
药学 | 550篇 |
中国医学 | 109篇 |
肿瘤学 | 297篇 |
出版年
2023年 | 54篇 |
2022年 | 169篇 |
2021年 | 270篇 |
2020年 | 162篇 |
2019年 | 249篇 |
2018年 | 328篇 |
2017年 | 218篇 |
2016年 | 210篇 |
2015年 | 270篇 |
2014年 | 414篇 |
2013年 | 492篇 |
2012年 | 647篇 |
2011年 | 780篇 |
2010年 | 360篇 |
2009年 | 341篇 |
2008年 | 536篇 |
2007年 | 579篇 |
2006年 | 477篇 |
2005年 | 468篇 |
2004年 | 397篇 |
2003年 | 323篇 |
2002年 | 272篇 |
2001年 | 172篇 |
2000年 | 166篇 |
1999年 | 116篇 |
1998年 | 78篇 |
1997年 | 54篇 |
1996年 | 47篇 |
1995年 | 34篇 |
1994年 | 36篇 |
1993年 | 30篇 |
1992年 | 52篇 |
1991年 | 67篇 |
1990年 | 35篇 |
1989年 | 27篇 |
1988年 | 38篇 |
1987年 | 25篇 |
1986年 | 36篇 |
1985年 | 33篇 |
1984年 | 30篇 |
1983年 | 24篇 |
1981年 | 19篇 |
1979年 | 17篇 |
1977年 | 17篇 |
1971年 | 16篇 |
1970年 | 27篇 |
1969年 | 33篇 |
1968年 | 26篇 |
1967年 | 23篇 |
1966年 | 16篇 |
排序方式: 共有9428条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Maria C. Chammas Andre C. Oliveira Mario J. D´Ávilla Pedro H. Moraes Marcelo Straus Takahashi 《Ultrasound in medicine & biology》2019,45(1):50-55
We prospectively evaluated the effectiveness of contrast-enhanced ultrasonography (CEUS) for differentiation of benign versus malignant portal vein thrombosis (PVT). We studied a total of 43 patients with chronic liver disease, hepatocellular carcinoma-suggestive nodules and confirmed PVT, in whom the nature of the PVT was confirmed by follow-up imaging (US, computed tomography and/or magnetic resonance imaging) performed up to 6 mo after CEUS. PVT was assessed by US, Doppler US and CEUS with respect to vessel wall disruption and/or invasion, color Doppler vascularization, pulsed Doppler vascularization pattern and CEUS enhancement and vascularization pattern, and thrombi were classified as benign or malignant based on these findings. Follow-up studies revealed malignant PVT in 22 of the 43 patients (51%) and benign PVT in 21 patients (49%). CEUS findings were consistent with follow-up studies in 41 of the 43 patients (95%), with κ?=?0.903 (p < 0.0001), sensitivity?=?91% and specificity?=?100%, indicating that CEUS can be confidently used to differentiate benign from malignant portal vein thrombosis in the setting of chronic liver disease. 相似文献
6.
7.
Alcides José Branco Filho William Kondo Luis Sérgio Nassif Mariana Jorge Garcia Rafael de Almeida Tirapelle Carlos Marcelo Dotti 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2006,10(3):326-331
BACKGROUND: Gastrogastric fistula is a communication between the proximal gastric pouch and the distal gastric remnant, rarely described in the realm of bariatric procedures. The aim of this study was to review the existing literature about this topic and to demonstrate its laparoscopic treatment. METHODS: An extensive literature review found several articles reporting this complication. However, no citation was found describing the steps of the laparoscopic management of this situation. RESULTS: Gastrogastric fistula occurs in up to 6% of Roux-en-Y gastric bypasses. Two theories exist for fistula formation: (1) it is a technical complication derived from the incomplete division of the stomach during the creation of the pouch, and (2) it occurs after a staple-line failure, developing a leak with an abscess, which then drains into the distal stomach forming the fistula. Early symptoms include fever, tachycardia, and abdominal pain. Failure in weight loss is a late clinical sign observed in these patients. Diagnosis is based on radiologic study, upper endoscopy and computed tomography. When identified in the acute postoperative course, laparoscopic treatment is easy. Chronic fistulas are difficult to manage, and the laparoscopic approach is an alternative to open surgery. CONCLUSIONS: Gastrogastric fistula is a possible complication of Roux-en-Y gastric bypass and its laparoscopic treatment is feasible. 相似文献
8.
9.
Rodrigo O Perez Angelita Habr-Gama Igor Proscurshim Fábio G Campos Desiderio Kiss Joaquim Gama-Rodrigues Ivan Cecconello 《Journal of gastrointestinal surgery》2007,11(11):1431-8; discussion 1438-40
BACKGROUND: The role of local excision for pT2 distal rectal cancer has been challenged because of the observation of high rates of lymph node metastases and local failure. However, neoadjuvant chemoradiation therapy (CRT) has led to increased local disease control and significant tumor downstaging, possibly decreasing rates of lymph node metastases. In this setting, a possible role for local excision of ypT2 has been suggested. METHODS: A total of 401 patients with distal rectal cancer underwent neoadjuvant CRT. Tumor response assessment was performed after at least 8 weeks from CRT completion. One hundred and twelve patients with complete clinical response were not immediately operated on and were excluded from the study, and 289 patients with incomplete clinical response were managed by radical surgery. Patients with final pathological stage ypT2 were analyzed to determine the risk of unfavorable pathological features that could represent unacceptable risk for local failure after local excision. RESULTS: Eighty-eight (30%) patients had ypT2 rectal cancer. Final ypT status was not associated with pretreatment radiological staging (p = 0.62). ypT status was significantly associated with the risk of lymph node metastases, risk of perineural and vascular invasion, and recurrence (p = 0.001). Lymph node metastases were present in 19% of patients with ypT2 rectal cancer. The risk of lymph node metastases in ypT2 was associated with the presence of perineural invasion (47% vs 4%; p = <0.001), vascular invasion (59% vs 6%; p < 0.001), and decreased mean interval CRT surgery (12 vs 18 weeks; p < 0.001), but not with mean tumor size (3.2 vs 3.1 cm; p = 0.8). Disease-free and overall survival rates were significantly better for patients with ypT2N0 (p = 0.02 and 0.006, respectively). Fifty-five (63%) patients with ypT2 had at least one unfavorable pathological feature for local excision (lymph node metastases, vascular or perineural invasion, mucinous type or tumor size >3 cm). CONCLUSION: Lymph node metastases were present in 19% of patients with ypT2 and were significantly associated with poor overall and disease-free survival rates. The risk of lymph node metastases could not be predicted by radiological staging or tumor size. Radical surgery should be considered the standard treatment option for ypT2 rectal cancer after CRT. 相似文献
10.
Paulo Cezar Galv?o do Amaral Euler de Medeiros ázaro Filho Thales Delmondes Galv?o Ettinger Eric Junior Galeno Egydio José de Magalh?es Neto Fabrício Mascarenhas Edvaldo Fahel 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2006,10(3):355-358
BACKGROUND: Randomized studies demonstrate that laparoscopic appendectomy yields better results compared with open techniques. We sought to identify factors that determine an extended hospital stay among patients undergoing laparoscopic appendectomy. METHODS: This was a prospective study including 669 patients undergoing laparoscopic appendectomy. We analyzed variables that can predict the length of hospital stay. RESULTS: Of 669 patients undergoing laparoscopic appendectomy, 141 stayed in the hospital for > or = 5 days (Group 1), and 97 stayed in the hospital for < or = 1 day after surgery (Group 2). The univariate analysis demonstrated that fever (P<0.0001), nausea and vomiting (P=0.060), leukocytosis (P<0.0001), gangrened or perforated intraoperative appearance of the appendix (P<0.0001), and appendix position behind the ileocecal junction (P<0.001) were related to a longer hospital stay. The multivariate analysis through logistical regression showed that the factors independently and significantly associated with an extended hospital stay were presurgical fever, appendix position behind the ileocecal junction, and intraoperative gangrened or perforated appearance of the appendix. CONCLUSION: Fever, appearance, and position of the appendix are factors related to an extended hospital stay. 相似文献