首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3929篇
  免费   313篇
  国内免费   72篇
耳鼻咽喉   90篇
儿科学   45篇
妇产科学   48篇
基础医学   704篇
口腔科学   63篇
临床医学   250篇
内科学   966篇
皮肤病学   263篇
神经病学   221篇
特种医学   210篇
外科学   554篇
综合类   14篇
一般理论   1篇
预防医学   91篇
眼科学   54篇
药学   359篇
中国医学   74篇
肿瘤学   307篇
  2023年   27篇
  2022年   64篇
  2021年   117篇
  2020年   55篇
  2019年   112篇
  2018年   112篇
  2017年   111篇
  2016年   158篇
  2015年   199篇
  2014年   246篇
  2013年   273篇
  2012年   384篇
  2011年   356篇
  2010年   280篇
  2009年   204篇
  2008年   268篇
  2007年   236篇
  2006年   222篇
  2005年   198篇
  2004年   152篇
  2003年   132篇
  2002年   128篇
  2001年   34篇
  2000年   11篇
  1999年   20篇
  1998年   30篇
  1997年   27篇
  1996年   22篇
  1995年   16篇
  1994年   12篇
  1993年   13篇
  1992年   6篇
  1991年   6篇
  1990年   4篇
  1989年   7篇
  1988年   11篇
  1987年   10篇
  1986年   7篇
  1985年   7篇
  1984年   6篇
  1982年   5篇
  1981年   9篇
  1980年   3篇
  1978年   1篇
  1977年   3篇
  1974年   2篇
  1972年   2篇
  1971年   1篇
  1969年   1篇
  1964年   1篇
排序方式: 共有4314条查询结果,搜索用时 15 毫秒
101.
102.
Jin KN  Lee JM  Kim SH  Shin KS  Lee JY  Han JK  Choi BI 《European radiology》2006,16(10):2284-2291
The purpose of this study was to determine whether multiplanar reconstruction (MPR) images can improve the accuracy of MDCT-based colorectal cancer preoperative staging by receiver-operating characteristic (ROC) analysis. Fifty-five patients with colorectal cancer underwent contrast-enhanced CT colonography using an 8- or 16-row scanner. Two separate interval reviews of the axial MDCT datasets with/without MPR images (coronal and sagittal) were performed independently by two radiologists blinded to both the colonoscopic and histopathologic results. At each review session, the radiologists were asked to determine the colorectal cancer TNM stage within the context of differentiating ≤T3 from T4, N0 from ≥N1 and M0 from M1 using a five-point confidence scale. The radiologists’ performance for staging the colorectal cancer using axial CT datasets with/without MPR images was evaluated using ROC analysis. Sensitivities, specificities and interobserver agreement were assessed. When MPR images were added, significant improvement was achieved by both radiologists for differentiating N0 from ≥N1 in terms of both AZ (0.651 to 0.769; 0.573 to 0.713) and specificity (26.7 to 69.2%; 23.1 to 76.9%) (P<0.05). For T staging, ROC analysis failed to show a significant improvement in terms of differentiating ≤T3 from T4 for either radiologist (P>0.05), but a significant improvement in the specificity (70 to 90%; 80 to 92%) was achieved by one radiologist (P<0.05). In terms of the M staging, a significant improvement in the Az (0.844 to 0.996) was observed for the combined interpretation of the axial and MPR images by one radiologist (P<0.05). Furthermore, substantial or almost perfect interobserver agreement was achieved for all TNM stagings for the combined interpretations (κ=0.641–0.866), whereas only fair to substantial agreement was achieved for the axial images alone (κ=0.337-0.707). In conclusion, the combined interpretation of the axial and MPR MDCT images significantly improved the local staging of colorectal cancer compared with assessments based on axial images alone.  相似文献   
103.
104.
OBJECTIVE: Plaque stability and thrombogenicity contribute to development and clinical expression of atherosclerosis. Experimental studies have shown that lipoproteins or mevalonate regulate matrix metalloproteinase (MMP)-9, tissue factor (TF), plasminogen activator inhibitor-1 (PAI-1) expression, providing nonlipid mechanism. METHODS: We administered simvastatin 20 mg daily during 14 weeks to 32 hypercholesterolemic patients with coronary artery disease. RESULTS: Compared with pretreatment values, simvastatin significantly lowered lipoprotein levels (all P<0.01). Compared with pretreatment values, simvastatin significantly lowered plasma levels of MMP-9, TF, and PAI-1 (P=0.009, P=0.032, and P=0.007, respectively). There were significant inverse correlations between pretreatment MMP-9, TF activity or PAI-1 antigen and the degree of change in those levels after simvastatin (r=-0.793, P<0.001; r=-0.482, P=0.005 and r=-0.590, P<0.001, respectively). Of interest, there were significant correlation between pretreatment or percent changes in MMP-9 levels and pretreatment or percent changes in PAI-1 antigen (r=0.293, P=0.019 and r=0.375, P=0.034, respectively). However, no significant correlations between lipoprotein levels and levels of plaque stability or thrombogenicity markers were determined. CONCLUSIONS: Reduction of plaque stability and thrombogenicity markers with statin may contribute to the cardiovascular event reduction and explain the early clinical benefit in clinical trials, independent of lipoprotein changes.  相似文献   
105.
BackgroundDepression and sleep–wake disorders are recognized as one of the major problems among emergency physicians. While depression is more common in females than in males, the associated factors linking depression and sleep–wake disorders in emergency physicians, particularly females, remain unknown.ObjectiveTo analyze the prevalence of depression and sleep–wake problems among emergency medicine (EM) residents in South Korea and to identify the gender differences and situations that adversely predispose female residents to mental health problems.MethodsWe conducted a cross-sectional analysis using the data collected from the 2019 National EM Residents Wellness Survey targeting all of 630 EM residents in South Korea. The survey included variables potentially influencing depression and sleep–wake problems, such as personal characteristics, work-related stress, and extrinsic environment. Information regarding medical conditions, depression, job stress, and sleep deprivation was obtained using the self-administered Patient Health Questionnaire (PHQ-9), the Apgar Wellness Score (AWS), and the Epworth Sleepiness Scale (ESS). We analyzed the data using IBM SPSS Statistics version 25 and MedCalc version 17.ResultsA total of 384 residents participated in the survey. Overall, 27.5% of the EM residents met the criteria for at least moderate depression and 36.9% of the EM residents had sleep-related problems. We found that difficulty in trading the shift schedule and frequent night shifts was associated with depression (p = .001, p = .005; respectively). Female residents demonstrated an increased risk of depression and sleepiness compared to their male counterparts (odds ratio [OR] 1.95, OR 1.81; respectively). In addition, logistic regression analysis revealed significant differences by gender in depression with regards to flexibility of trading shifts (p = .005), level of training in the emergency medical centre (p = .035), and frequent night shifts (p = .010).ConclusionsApproximately, one-third of EM residents report depression and sleep–wake problems, with female residents showing a higher risk than male residents. Several risk factors were identified, and future strategies should be aimed to address these issues to improve the training environment and overall wellbeing of EM residents.

KEY MESSAGES

  • The prevalence of depression and sleep-related problems were, respectively, 1.95 and 1.81 times higher in female residents compared to their male colleagues.
  • The associated risk factors for depression were flexibility of shift trade, level of training in the emergency medical centre, and frequency of night shifts.
  • Improving the training environment and facilities, as well as offering more flexible duty trading options can provide potential opportunities to reduce the risk.
  相似文献   
106.
107.
With limited data comparing hematopoietic cell transplant outcomes between myeloablative total body irradiation (TBI) containing and non-TBI regimens in children with de novo acute myeloid leukemia, the aim of this study was to compare transplant-outcomes between these regimens. Cox regression models were used to compare transplant-outcomes after TBI and non-TBI regimens in 624 children transplanted between 2008 and 2016. Thirty two percent (n=199) received TBI regimens whereas 68% (n=425) received non-TBI regimens. Five-year non-relapse mortality was higher with TBI regimens (22% vs. 11%, P<0.0001) but relapse was lower (23% vs. 37%, P<0.0001) compared to non-TBI regimens. Consequently, overall (62% vs. 60%, P=1.00) and leukemia-free survival (55% vs. 52%, P=0.42) did not differ between treatment groups. Grade 2-3 acute graft versus host disease was higher with TBI regimens (56% vs. 27%, P<0.0001) but not chronic graft versus host disease. The 3-year incidence of gonadal or growth hormone deficiency was higher with TBI regimens (24% vs. 8%, P<0.001) but there were no differences in late pulmonary, cardiac or renal impairment. In the absence of a survival advantage, the choice of TBI or non-TBI regimen merits careful consideration with the data favoring non-TBI regimens to limit the burden of morbidity associated with endocrine dysfunction.  相似文献   
108.
Backgrounds: Periodic endoscopic screening for oesophageal varices (OVs) and prophylactic treatment for high‐risk OVs (HOVs; medium/large OVs or small OVs plus red sign/decompensation) are currently recommended for all cirrhotic patients. However, if a simple, noninvasive test is available, many low‐risk patients may reliably avoid endoscopy. Aims: We conducted a large‐scale validation study of a simple, noninvasive test called P2/MS based on complete blood counts, (platelet count)2/[monocyte fraction (%) × segmented neutrophil fraction (%)], and compared it with other predictive tests for HOVs in B‐viral cirrhotic patients. Methods: From 2008 to 2009, we prospectively enrolled 318 consecutive B‐viral cirrhotic patients. All underwent endoscopy and laboratory evaluation. Results: An area under the receiver operating characteristic curve of P2/MS was 0.941 for HOVs, comparable with those of the age–spleen platelet ratio index (0.922, P=0.317) and spleen–platelet ratio index (0.922, P=0.324), and better than those of age–platelet index (0.653, P<0.001), aspartate aminotransferase (AST)–platelet ratio index (0.871, P<0.006) and AST‐alanine aminotransferase ratio (0.644, P<0.001). P2/MS<11 reliably identified 83 patients as having HOVs (94.0% positive predictive value), while at a cutoff of 25 and 179 as not having HOVs (94.4% negative predictive value). Overall, P2/MS reliably determined the likelihood of HOVs in 262 patients (82.4%). These cutoffs were validated internally using bootstrap resampling methods, which showed good agreement. Conclusions: P2/MS is a simple, accurate and economical method, reducing the need for endoscopy in B‐viral cirrhosis. Patients with P2/MS<11 should be considered for appropriate prophylactic treatments, while those with P2/MS>25 may avoid endoscopy reliably.  相似文献   
109.
PurposeAn association between baroreflex sensitivity (BRS) and the response to tilt training has not been reported in patients with neurally mediated syncope (NMS). This study sought to investigate the role of BRS in predicting the response to tilt training in patients with NMS.ResultsAfter tilt training, 52 patients (91.2%) achieved three consecutive negative responses to the HUT. In the supine position before upright posture during the first session of tilt training for responders and non-responders, the mean BRS was 18.17±10.09 ms/mm Hg and 7.99±5.84 ms/mm Hg (p=0.008), respectively, and the frequency of BRS ≥8.945 ms/mm Hg was 45 (86.5%) and 1 (20.0%; p=0.004), respectively. Age, male gender, frequency of syncopal events before HUT, type of NMS, phase of positive HUT, total number of tilt training sessions, and mean time of tilt training did not differ between the study groups. In the multivariate analysis, BRS <8.945 ms/mm Hg in the supine position (odds ratio 23.10; 95% CI 1.20-443.59; p=0.037) was significantly and independently associated with non-response to tilt training.ConclusionThe BRS value in the supine position could be a predictor for determining the response to tilt training in patients with NMS who are being considered for inpatient tilt training.  相似文献   
110.

Background/Aims

Transarterial chemoembolization (TACE) has long been used as a palliative therapy for unresectable hepatocellular carcinoma (HCC). High-dose hepatic arterial infusion chemotherapy (HAIC) has showed favorable outcomes in patients with intractable, advanced HCC. The aim of this study was to compare the effectiveness and safety of high-dose HAIC and conventional TACE using doxorubicin for advanced HCC.

Methods

The high-dose HAIC group comprised 36 patients who were enrolled prospectively from six institutions. The enrollment criteria were good liver function, main portal vein invasion (including vascular shunt), infiltrative type, bilobar involvement, and/or refractory to prior conventional treatment (TACE, radiofrequency ablation, or percutaneous ethanol injection), and documented progressive disease. Patients received 5-fluorouracil (500 mg/m2 on days 1~3) and cisplatin (60 mg/m2 on day 2 every 4 weeks) via an implantable port system. In the TACE group, 31 patients with characteristics similar to those in the high-dose HAIC group were recruited retrospectively from a single center. Patients underwent a transarterial infusion of doxorubicin every 4~8 weeks.

Results

Overall, 6 patients (8.9%) achieved a partial response and 20 patients (29.8%) had stable disease. The objective response rate (complete response+partial response) was significantly better in the high-dose HAIC group than in the TACE group (16.7% vs. 0%, P=0.030). Overall survival was longer in the high-dose HAIC group than in the TACE group (median survival, 193 vs. 119 days; P=0.026). There were no serious adverse effects in the high-dose HAIC group, while hepatic complications occurred more often in the TACE group.

Conclusions

High-dose HAIC appears to improve the tumor response and survival outcome compared to conventional TACE using doxorubicin in patients with intractable, advanced HCC.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号