全文获取类型
收费全文 | 15114篇 |
免费 | 963篇 |
国内免费 | 273篇 |
专业分类
耳鼻咽喉 | 221篇 |
儿科学 | 124篇 |
妇产科学 | 152篇 |
基础医学 | 2501篇 |
口腔科学 | 281篇 |
临床医学 | 1449篇 |
内科学 | 2823篇 |
皮肤病学 | 493篇 |
神经病学 | 1063篇 |
特种医学 | 1284篇 |
外科学 | 1791篇 |
综合类 | 77篇 |
一般理论 | 3篇 |
预防医学 | 494篇 |
眼科学 | 238篇 |
药学 | 1887篇 |
中国医学 | 268篇 |
肿瘤学 | 1201篇 |
出版年
2024年 | 8篇 |
2023年 | 127篇 |
2022年 | 471篇 |
2021年 | 658篇 |
2020年 | 310篇 |
2019年 | 464篇 |
2018年 | 552篇 |
2017年 | 465篇 |
2016年 | 648篇 |
2015年 | 872篇 |
2014年 | 1019篇 |
2013年 | 1096篇 |
2012年 | 1469篇 |
2011年 | 1493篇 |
2010年 | 900篇 |
2009年 | 684篇 |
2008年 | 885篇 |
2007年 | 874篇 |
2006年 | 703篇 |
2005年 | 648篇 |
2004年 | 559篇 |
2003年 | 405篇 |
2002年 | 317篇 |
2001年 | 174篇 |
2000年 | 139篇 |
1999年 | 82篇 |
1998年 | 60篇 |
1997年 | 50篇 |
1996年 | 32篇 |
1995年 | 20篇 |
1994年 | 22篇 |
1993年 | 17篇 |
1992年 | 27篇 |
1991年 | 23篇 |
1990年 | 16篇 |
1989年 | 16篇 |
1988年 | 11篇 |
1987年 | 4篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1983年 | 4篇 |
1977年 | 1篇 |
1976年 | 6篇 |
1975年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 25 毫秒
101.
Kyung A Kang Young Kon Kim EunJu Kim Woo Kyoung Jeong Dongil Choi Won Jae Lee Sin-Ho Jung Sun-Young Baek 《Korean journal of radiology》2015,16(5):1038-1046
Objective
To assess the value of applying MultiVane to liver T2-weighted imaging (T2WI) compared with conventional T2WIs with emphasis on detection of focal liver lesions.Materials and Methods
Seventy-eight patients (43 men and 35 women) with 86 hepatic lesions and 20 pancreatico-biliary diseases underwent MRI including T2WIs acquired using breath-hold (BH), respiratory-triggered (RT), and MultiVane technique at 3T. Two reviewers evaluated each T2WI with respect to artefacts, organ sharpness, and conspicuity of intrahepatic vessels, hilar duct, and main lesion using five-point scales, and made pairwise comparisons between T2WI sequences for these categories. Diagnostic accuracy (Az) and sensitivity for hepatic lesion detection were evaluated using alternative free-response receiver operating characteristic analysis.Results
MultiVane T2WI was significantly better than BH-T2WI or RT-T2WI for organ sharpness and conspicuity of intrahepatic vessels and main lesion in both separate reviews and pairwise comparisons (p < 0.001). With regard to motion artefacts, MultiVane T2WI or BH-T2WI was better than RT-T2WI (p < 0.001). Conspicuity of hilar duct was better with BH-T2WI than with MultiVane T2WI (p = 0.030) or RT-T2WI (p < 0.001). For detection of 86 hepatic lesions, sensitivity (mean, 97.7%) of MultiVane T2WI was significantly higher than that of BH-T2WI (mean, 89.5%) (p = 0.008) or RT-T2WI (mean, 84.9%) (p = 0.001).Conclusion
Applying the MultiVane technique to T2WI of the liver is a promising approach to improving image quality that results in increased detection of focal liver lesions compared with conventional T2WI. 相似文献102.
Suh JS Cho J Lee SH Shin KH Yang WI Lee JH Cho JH Suh KJ Lee YJ Ryu KN 《Skeletal radiology》2000,29(12):680-689
Objective. To present the MR and angiographic findings of alveolar soft part sarcoma (ASPS).
Design and patients. MR examinations (12 tumors of 10 patients) of ASPS performed at multiple hospitals were retrospectively reviewed. The tumors
were found in the thigh (n=4), lower leg (n=4), femur (n=2, local metastasis), scalp (n=1) and arm (n=1). The MR signal characteristics including signal intensity, homogeneity and signal void of lesions and bony invasion including
direct invasion or local metastasis were evaluated. Angiographic findings (n=4) and post-embolotherapy follow-up MR imaging (n=2) findings were also assessed.
Results. Local bony metastasis was found in two cases. Seven tumors showed heterogeneous high signal intensity on T1- and T2-weighted
images with good enhancement. One tumor had a very high signal on T1-weighted images. Eight tumors (67%) showed numerous signal
voids in or near the tumors. All four angiographic studies showed numerous enlarged vessels, arteriovenous shunts and delayed
washout. Two cases mimicked arteriovenous malformations on angiographic studies but MR images demonstrated solid soft tissue
components as well as tortuous vessels.
Conclusions. High signal on T1-weighted image and numerous signal voids are highly suggestive of ASPS, although they are not universal
as has been suggested and arteriovenous malformation should be included in the differential diagnosis. Local bony metastases
in ASPS were seen in two cases and should be carefully investigated.
Received: 12 April 2000 Revision requested: 27 June 2000, 8 August 2000 Revision received: 2 August 2000, 21 August 2000 Accepted:
22 August 2000 相似文献
103.
104.
Anterior translocation of the pulmonary root was used as a new approach to the staged repair of Taussig-Bing anomaly with an interrupted aortic arch. It was performed to construct the right ventricle outflow tract with intraventricular baffling of the left ventricle to the aorta as the second stage operation after repair of the interrupted arch and pulmonary artery banding. This technique allows minimization of pulmonary regurgitation and has the major theoretical advantage for growth potential, which could diminish the need for reoperation. 相似文献
105.
Adenosine has shown antinociceptive action via spinal adenosine receptors. There are four types of adenosine receptors: A1, A2A, A2B, and A3. We characterized the nature of types of adenosine receptors for the control of nociception at the spinal level. For nociception, formalin solution (5%, 50 microL) was injected into the hindpaw of male Sprague-Dawley rats. The effects of intrathecal adenosine A1 (CPA), A2A (DPMA), and A3 (IB-MECA) receptor agonists were examined. CPA and IB-MECA produced limited or no effect on the early phase response of the formalin test, respectively, but the two drugs depressed the late phase response. DPMA suppressed both phase responses. CPA was the most potent drug among the three in the late phase. These results suggest that spinal adenosine A1 and A2A receptors may be involved in the modulation of the early and the late phase responses of the formalin test, whereas adenosine A3 receptor may be involved in the regulation of the late phase response. 相似文献
106.
Fu L. Luan Linda J. Stuckey Jeong M. Park Daniel Kaul Diane Cibrik Akinlolu Ojo 《Journal of the American Society of Nephrology : JASN》2009,20(11):2449-2458
The risk of late-onset cytomegalovirus (CMV) infection remains a concern in seronegative kidney and/or pancreas transplant recipients of seropositive organs despite the use of antiviral prophylaxis. The optimal duration of prophylaxis is unknown. We studied the cost effectiveness of 6- versus 3-mo prophylaxis with valganciclovir. A total of 222 seronegative recipients of seropositive kidney and/or pancreas transplants received valganciclovir prophylaxis for either 3 or 6 mo during two consecutive time periods. We assessed the incidence of CMV infection and disease 12 mo after completion of prophylaxis and performed cost-effectiveness analyses. The overall incidence of CMV infection and disease was 26.7% and 24.4% in the 3-mo group and 20.9% and 12.1% in the 6-mo group, respectively. Six-month prophylaxis was associated with a statistically significant reduction in risk for CMV disease (HR, 0.35; 95% CI, 0.17 to 0.72), but not infection (HR, 0.65; 95% CI, 0.37 to 1.14). Cost-effectiveness analyses showed that 6-mo prophylaxis combined with a one-time viremia determination at the end of the prophylaxis period incurred an incremental cost of $34,362 and $16,215 per case of infection and disease avoided, respectively, and $8,304 per one quality adjusted life-year gained. Sensitivity analyses supported the cost effectiveness of 6-mo prophylaxis over a wide range of valganciclovir and hospital costs, as well as variation in the incidence of CMV disease. In summary, 6-mo prophylaxis with valganciclovir combined with a one-time determination of viremia is cost effective in reducing CMV infection and disease in seronegative recipients of seropositive kidney and/or pancreas transplants.Cytomegalovirus (CMV) infection remains one of most common opportunistic infections in solid organ transplant patients despite availability of specific and efficacious anti-viral drugs.1,2 Solid organ transplant patients who have a negative CMV serology and receive an organ from a positive CMV serologic donor (D+/R−) have the highest incidence of CMV disease with and without prophylaxis.2–5 Although the risk for CMV disease persists for life, the majority of cases occur shortly after completion of prophylaxis, often within the first year after transplant.6 CMV disease causes significant morbidity, increases mortality, and is associated with inferior transplant outcomes, particularly in the case of kidney transplantation.7–10 Furthermore, the presence of CMV disease is one of the most frequent infectious causes of hospitalization early after transplantation, increasing the total cost of kidney transplantation and reducing its overall effectiveness.7,11–13Valganciclovir (VGCV) is an effective anti-CMV agent for prophylaxis and treatment of CMV disease that is widely used in transplantation.2,14–16 Although the recommended dose for CMV prophylaxis is 900 mg daily adjusted for renal function, a recent study showed that VGCV at 450 mg daily provides similar drug exposure compared with oral ganciclovir (GCV) at 1000 mg three times daily in kidney transplant patients, a dose similarly effective for CMV prophylaxis.2,17 In most studies, VGCV prophylaxis consisted of 100 d after transplant, after which time the risk of CMV infection and disease increased.2,18,19 Extending the duration of VGCV prophylaxis beyond the early post-transplant period may abrogate this transient increase in the risk of infection and disease.20,21 In this regard, the optimal duration of prophylaxis for CMV D+/R− patients has not been determined and is the subject of ongoing study.22 Cost, efficacy, and safety are important factors in determining the optimal duration of VGCV prophylaxis. Over the past two decades, various strategies have been used including pre-emptive versus universal prophylaxis and shorter versus longer period of prophylaxis.20,21,23,24 Although several clinical studies comparing universal prophylaxis versus pre-emptive anti-viral therapy have found similar efficacy and cost in managing CMV infection across various combinations of donor and recipient CMV serologic status, two meta-analyses did find that the use of universal prophylaxis was associated with reduced risk for CMV disease and death.23–26This study is based on a single center experience comparing two CMV prophylaxis strategies. We report here the clinical outcome and cost-effectiveness analyses of 6- versus 3-mo VGCV prophylaxis in CMV D+/R− de novo kidney and/or pancreas transplant patients. 相似文献
107.
Shin JI Park JM Shin YH Kim JH Kim PK Lee JS Jeong HJ 《Pediatric nephrology (Berlin, Germany)》2005,20(8):1093-1097
To evaluate the efficacy of cyclosporin A (CyA) for treating severe Henoch-Schönlein nephritis (HSN), seven patients with nephrotic syndrome, aged 3.9–13.8 years (mean 6.5 years), were analyzed retrospectively. Mean follow-up times were 5.5 years (range 2–9 years). All underwent renal biopsy before treatment, and follow-up renal biopsy was performed in six of the seven patients. All patients improved, with 24-h protein declining from a mean of 9.2 g/m2/day (range 1.5–16 g/m2/day) to 0.3 g/m2/day (range 0.03–1.2 g/m2/day) (p=0.016) and serum albumin increasing from a mean of 2.1 g/dl (range 1.5–2.4 g/dl) to 4.6 g/dl (range 3.5–5.3 g/dl) (p=0.016) after CyA therapy. The activity index decreased significantly at the second renal biopsies obtained at a mean interval of 11.7 months after the first (6.4±3.3 vs 3.5±1.2, p=0.042, respectively), while the chronicity index and the tubulointerstitial scores did not change. On the immunofluorescent findings at the second biopsies, the degree of deposits of immunoglobulins such as IgA, IgM, C3, and fibrinogen decreased in five of the six patients. Although this case series is without controls, our study suggests that CyA may be beneficial to a subset of HSN patients with nephrotic syndrome. 相似文献
108.
Cyclosporine-induced renal injury induces toll-like receptor and maturation of dendritic cells 总被引:3,自引:0,他引:3
BACKGROUND: The toll-like receptor (TLR) is stimulated by not only pathogen-associated molecular patterns but also endogenous TLR ligands provided by injured cells. The influence of cyclosporine A (CsA)-induced renal injury on TLR expression and subsequent signaling pathway was evaluated. METHODS: Induction of chronic CsA nephropathy was made by administering CsA (15 mg/kg/day) for 28 days in rats. The TLR2 and TLR4 mRNA and protein expression, TLR-signaling pathway (MYD88, NF-kappaB and AP-1), putative TLR ligand (heat shock protein 70 [HSP70]), and maturation of dendritic cells were evaluated in CsA-treated rat kidneys. RESULTS: Long-term CsA treatment upregulated TLR2 and TLR4 mRNA and protein expression on renal tubular cells, and these were accompanied by increased MYD88, NF-kappaB and AP-1 expression. Putative TLR ligand (HSP70) was also significantly increased in CsA-treated rat kidney compared with vehicle-treated rat kidney. CsA-treatment increased expression of TNF-alpha mRNA, the number of dendritic cells, and expression of MHC class II antigen. Double-labeling of markers of dendritic cells and MHC class II antigen revealed that matured dendritic cells increased in CsA-treated rat kidney. CONCLUSIONS: CsA-induced renal injury stimulates components of innate immunity, and this finding suggests close association between CsA-induced renal injury and activation of innate immunity. 相似文献
109.
The lateral surgical approach to jugular foramen schwannomas (JFS) may result in complications such as temporary facial nerve
palsy (FNP) and hearing loss due to the complicated anatomical location. Ten patients with JFS surgically treated by variable
methods of lateral approach were retrospectively reviewed with emphasis on surgical methods, postoperative FNP, and lower
cranial nerve status. Gross total removal of the tumors was achieved in eight patients. Facial nerves were rerouted at the
first genu (1G) in six patients and at the second genu in four patients. FNP of House–Brackmann (HB) grade III or worse developed
immediately postoperatively in six patients regardless of the extent of rerouting. The FNP of HB grade III persisted for more
than a year in one patient managed with rerouting at 1G. Among the lower cranial nerves, the vagus nerve was most frequently
paralyzed preoperatively and lower cranial nerve palsies were newly developed in two patients. The methods of the surgical
approach to JFS can be modified depending on the size and location of tumors to reduce injury of the facial nerve and loss
of hearing. Careful manipulation and caution are also required for short facial nerve rerouting as well as for long rerouting
to avoid immediately postoperative FNP. 相似文献
110.
Kwang-Beom Lee MD PhD Kyung-Do Ki MD PhD Jong-Min Lee MD PhD Jae-Kwan Lee MD PhD Jae Weon Kim MD PhD Chi-Heum Cho MD PhD Seok-Mo Kim MD PhD Sang-Yoon Park MD PhD Dae-Hoon Jeong MD PhD Ki-Tae Kim MD PhD 《Annals of surgical oncology》2009,16(10):2882-2887