全文获取类型
收费全文 | 2375379篇 |
免费 | 198911篇 |
国内免费 | 4252篇 |
专业分类
耳鼻咽喉 | 34455篇 |
儿科学 | 72955篇 |
妇产科学 | 63298篇 |
基础医学 | 334516篇 |
口腔科学 | 68553篇 |
临床医学 | 215743篇 |
内科学 | 468564篇 |
皮肤病学 | 48298篇 |
神经病学 | 200684篇 |
特种医学 | 96172篇 |
外国民族医学 | 886篇 |
外科学 | 361354篇 |
综合类 | 56239篇 |
现状与发展 | 1篇 |
一般理论 | 989篇 |
预防医学 | 191461篇 |
眼科学 | 55549篇 |
药学 | 178266篇 |
4篇 | |
中国医学 | 4361篇 |
肿瘤学 | 126194篇 |
出版年
2018年 | 25002篇 |
2017年 | 19270篇 |
2016年 | 21039篇 |
2015年 | 23863篇 |
2014年 | 34155篇 |
2013年 | 51695篇 |
2012年 | 70303篇 |
2011年 | 73971篇 |
2010年 | 43286篇 |
2009年 | 41429篇 |
2008年 | 70090篇 |
2007年 | 74448篇 |
2006年 | 75230篇 |
2005年 | 73218篇 |
2004年 | 70363篇 |
2003年 | 67855篇 |
2002年 | 66951篇 |
2001年 | 112453篇 |
2000年 | 116422篇 |
1999年 | 97828篇 |
1998年 | 26216篇 |
1997年 | 23815篇 |
1996年 | 23771篇 |
1995年 | 24480篇 |
1994年 | 23043篇 |
1993年 | 21447篇 |
1992年 | 79324篇 |
1991年 | 76423篇 |
1990年 | 73582篇 |
1989年 | 70836篇 |
1988年 | 65806篇 |
1987年 | 64788篇 |
1986年 | 61309篇 |
1985年 | 58397篇 |
1984年 | 44165篇 |
1983年 | 37570篇 |
1982年 | 22808篇 |
1981年 | 20243篇 |
1979年 | 41231篇 |
1978年 | 28926篇 |
1977年 | 24259篇 |
1976年 | 22761篇 |
1975年 | 23919篇 |
1974年 | 29613篇 |
1973年 | 28026篇 |
1972年 | 26215篇 |
1971年 | 24161篇 |
1970年 | 22739篇 |
1969年 | 21077篇 |
1968年 | 19130篇 |
排序方式: 共有10000条查询结果,搜索用时 49 毫秒
991.
992.
993.
Raghuveer C. Muppavarapu Michael J. Waters Matthew I. Leibman Mark R. Belsky David E. Ruchelsman 《Hand (New York, N.Y.)》2015,10(2):260-265
IntroductionThe aim of this study is to compare the efficacy of collagenase injections with that of fasciectomy in the treatment of Dupuytren’s contracture.MethodsThis is a case–control retrospective study. We reviewed the electronic medical records from January 2009 through January 2013, identifying 142 consecutive patients who underwent either fasciectomy or collagenase injection. Exclusion criteria for both groups were age <18 years, pregnant women, and arthroplasty or arthrodesis of the treated joint. Follow-up data beyond 1-year duration was available for 117 of the patients: 44 patients who had undergone fasciectomy, and 73 patients who had received collagenase injection. The primary outcome measure in this study was resolution of joint contracture to 0–5° deficit of full extension. Data was analyzed using two-sample t tests for continuous data and chi-square test for categorical data. A significant P value was set at <0.05.ResultsAt the latest follow-up, significantly more joints treated with fasciectomy met the primary outcome measure. Metacarpophalangeal (MP) joints responded better than the proximal interphalangeal (PIP) joints for both treatments. At the latest follow-up (14.2 months for collagenase, 16.3 months for fasciectomy), 46 % of MP joints treated with collagenase and 68 % of MP joints treated with fasciectomy maintained resolution of joint contracture. Sub-analysis of the affected joints based on the severity of initial contracture demonstrated that MP and PIP joints with contractures <45° responded better than more severely contracted joints (>45°).ConclusionsFasciectomy yields a greater mean magnitude of correction for digital contractures at the latest follow-up when compared to collagenase. Both treatments were more effective for treatment of MP joint contracture compared to PIP joint contracture.
Level of Evidence
Level III, therapeutic. 相似文献994.
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
995.
996.
997.
Maadrika M.N.P. Kanglie Nanko de Graaf Femke Beije Elise M.J. Brouwers Sabine D.M. Theuns-Valks Frits H. Jansen Diederick B.W. de Roy van Zuidewijn Bas Verhoeven Rick R. van Rijn Roel Bakx 《Journal of pediatric surgery》2019,54(3):500-506
Background
There is a lack of studies addressing the occurrence of negative intraoperative findings (that is the absence of intussusception) after an unsuccessful hydrostatic reduction of an ileocolic intussusception. The aim of this study is to determine the incidence of negative intraoperative findings after unsuccessful hydrostatic reduction of ileocolic intussusception.Methods
We conducted a multicentre retrospective study of all children aged 0–18?years treated for ileocolic intussusception from January 1, 2010 to December 31, 2015 in 9 Dutch hospitals. Primary outcome measure was the percentage of children without an intussusception during surgical exploration after unsuccessful hydrostatic reduction.Results
In the study period 436 patients were diagnosed with an ileocolic intussusception. Of these, 408 patients underwent hydrostatic reduction of an ileocolic intussusception. 112 patients (27.5%) underwent surgery after an unsuccessful hydrostatic reduction. In 13 (11.6%) patients no intraoperative evidence of intussusception was found. Patients who underwent surgical intervention after unsuccessful hydrostatic reduction were significantly younger than patients who had a successful hydrostatic reduction; there was no gender difference.Conclusion
A substantial number of children (11.6%) underwent a laparotomy after unsuccessful hydrostatic reduction in whom no intussusception was found intraoperatively. We suggest initiating laparoscopy instead of laparotomy when surgery is necessary.Level of evidence
Level II. 相似文献998.
Dave R. Lal Samir K. Gadepalli Cynthia D. Downard Peter C. Minneci Michelle Knezevich Thomas H. Chelius Cooper T. Rapp Deborah Billmire Steven Bruch R. Carland Burns Katherine J. Deans Mary E. Fallat Jason D. Fraser Julia Grabowski Ferdynand Hebel Michael A. Helmrath Ronald B. Hirschl Rashmi Kabre Thomas T. Sato 《Journal of pediatric surgery》2019,54(4):688-692
Purpose
Right sided aortic arch (RAA) is a rare anatomic finding in infants with esophageal atresia with or without tracheoesophageal fistula (EA/TEF). In the presence of RAA, significant controversy exists regarding optimal side for thoracotomy in repair of the EA/TEF. The purpose of this study was to characterize the incidence, demographics, surgical approach, and outcomes of patients with RAA and EA/TEF.Methods
A multi-institutional, IRB approved, retrospective cohort study of infants with EA/TEF treated at 11 children's hospitals in the United States over a 5-year period (2009 to 2014) was performed. All patients had a minimum of one-year follow-up.Results
In a cohort of 396 infants with esophageal atresia, 20 (5%) had RAA, with 18 having EA with a distal TEF and 2 with pure EA. Compared to infants with left sided arch (LAA), RAA infants had a lower median birth weight, (1.96?kg (IQR 1.54–2.65) vs. 2.57?kg (2.00–3.03), p?=?0.01), earlier gestational age (34.5?weeks (IQR 32–37) vs. 37?weeks (35–39), p?=?0.01), and a higher incidence of congenital heart disease (90% vs. 32%, p?<?0.0001). The most common cardiac lesions in the RAA group were ventricular septal defect (7), tetralogy of Fallot (7) and vascular ring (5). Seventeen infants with RAA underwent successful EA repair, 12 (71%) via right thoracotomy and 5 (29%) through left thoracotomy. Anastomotic strictures trended toward a difference in RAA patients undergoing right thoracotomy for primary repair of their EA/TEF compared to left thoracotomy (50% vs. 0%, p?=?0.1). Side of thoracotomy in RAA patients undergoing EA/TEF repair was not significantly associated with mortality, anastomotic leak, recurrent laryngeal nerve injury, recurrent fistula, or esophageal dehiscence (all p?>?0.29).Conclusion
RAA in infants with EA/TEF is rare with an incidence of 5%. Compared to infants with EA/TEF and LAA, infants with EA/TEF and RAA are more severely ill with lower birth weight and higher rates of prematurity and complex congenital heart disease. In neonates with RAA, surgical repair of the EA/TEF is technically feasible via thoracotomy from either chest. A higher incidence of anastomotic strictures may occur with a right-sided approach.Level of evidence
Level III. 相似文献999.
Mahwash Kassi Venkateshwar Polsani Robert C. Schutt Solomon Wong Faisal Nabi Michael J. Reardon Dipan J. Shah 《The Journal of thoracic and cardiovascular surgery》2019,157(5):1912-1922.e2
Background
The purpose of this analysis is to describe the differences in cardiac magnetic resonance characteristics between benign and malignant tumors, which would be helpful for surgical planning.Methods
This was a prospective cohort study of 130 patients who underwent cardiac magnetic resonance imaging for evaluation of a suspected cardiac mass. After excluding thrombi and tumors without definitive diagnosis, 66 tumors were evaluated for morphologic features and tissue composition.Results
Of the 66 patients, 39 (59.0%) had malignant tumors and 27 (41.0%) had benign tumors. Patients with malignant tumors were younger when compared with those with benign tumors (age 51 years [42.8-60.0] vs 65 years [60.0-71.0] median). Malignant tumors more often demonstrated tumor invasion (69% vs 0% P < .001) and were more often associated with pericardial effusion (41% vs 7.4% P = .004). Presence of first-pass perfusion (100% vs 33% P < .001) and late gadolinium enhancement (100% vs 59.2%, P < .001) were significantly higher in malignant tumors. In logistic regression modeling, tumor invasion (P < .001) and first-pass perfusion (P < .001) were independently associated with malignancy. Furthermore, using classification and regression tree analysis, we developed a decision tree algorithm to help differentiate benign from malignant tumors (diagnostic accuracy ~90%). The algorithm-weighted cost of misclassifying a malignant tumor as benign was twice that of classifying a benign tumor as malignant.Conclusions
Our study demonstrates that cardiac magnetic resonance imaging is a useful noninvasive method for differentiating malignant from benign cardiac tumors. Tumor size, invasion, and first-pass perfusion were useful imaging characteristics in differentiating benign from malignant tumors. 相似文献1000.
John P. Sundberg Kathleen A. Silva Victoria E. Kennedy John J. Wilson Nicholas E. Gott Beth A. Sundberg Derry C. Roopenian 《Experimental dermatology》2019,28(9):1091-1093
2‐deoxy D‐glucose (2DG) was tested for efficacy in treating alopecia areata using the C3H/HeJ skin graft model. 2DG has proven to be efficacious in treatment of various mouse models of autoimmunity with minimal serious side effects noted. This agent has been shown to normalize abnormally activated T‐cell populations while also preventing cell surface expression of NKG2D; key factors defining alopecia areata disease progression. Daily oral ingestion of 2DG via drinking water to mice with patchy or diffuse alopecia areata for 16 weeks failed to prevent expansion of alopecia or cause regrowth of hair in treated mice. Histologically, there were no differences between treated and control groups. These results indicate that, while 2DG is effective for some autoimmune diseases, it was not efficacious for the cell‐mediated autoimmune mouse disease, alopecia areata. 相似文献