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   3512篇
  免费   140篇
  国内免费   29篇
耳鼻咽喉   89篇
儿科学   240篇
妇产科学   197篇
基础医学   279篇
口腔科学   194篇
临床医学   227篇
内科学   635篇
皮肤病学   82篇
神经病学   279篇
特种医学   107篇
外科学   909篇
综合类   30篇
一般理论   3篇
预防医学   56篇
眼科学   85篇
药学   119篇
肿瘤学   150篇
  2024年   3篇
  2023年   35篇
  2022年   72篇
  2021年   123篇
  2020年   88篇
  2019年   93篇
  2018年   117篇
  2017年   101篇
  2016年   130篇
  2015年   164篇
  2014年   154篇
  2013年   181篇
  2012年   258篇
  2011年   271篇
  2010年   143篇
  2009年   131篇
  2008年   234篇
  2007年   245篇
  2006年   238篇
  2005年   242篇
  2004年   196篇
  2003年   124篇
  2002年   120篇
  2001年   39篇
  2000年   36篇
  1999年   34篇
  1998年   11篇
  1997年   11篇
  1996年   6篇
  1995年   16篇
  1994年   3篇
  1993年   5篇
  1992年   10篇
  1991年   4篇
  1990年   5篇
  1989年   3篇
  1988年   9篇
  1987年   7篇
  1986年   4篇
  1985年   3篇
  1984年   4篇
  1983年   1篇
  1980年   1篇
  1978年   2篇
  1977年   1篇
  1975年   1篇
  1970年   1篇
  1909年   1篇
排序方式: 共有3681条查询结果,搜索用时 15 毫秒
71.
Objective: To evaluate the effect of dopamine on thyroid hormone tests and prolactin (PRL) and to assess requirement for L-thyroxin (LT4).

Methods: The infants (n?=?102) were divided into three groups (Group 1; received no dopamine, Group 2 received ≤25?mg/kg cumulative dose and Group 3; received >25?mg/kg cumulative dose). Blood samples were taken at 6–8 days (timepoint 1), 13–15 days (timepoint 2), and 4–6 weeks of life (timepoint 3).

Results: Respiratory distress syndrome was higher in group 2 and 3. Patnet ductus arteriosus was higher in group 3 than in groups 1 and 2. Duration and cumulative dose in group 3 were higher than group 2. There was no difference between thyroid hormones that were taken after stopping infusion at timepoint 3 among all groups. No therapy with LT4 was needed. PRL levels were higher at timepoint 1 in group 1 than compared to group 2 and 3 (p?p?>?0.05). This difference was disappeared at following timepoints.

Conclusions: The release of TSH, FT3, FT4 and PRL were not inhibited and prophylactic thyroid hormone treatment was not required in VLBW infants receiving dopamine infusions.  相似文献   
72.
Thrombotic microangiopathies (TMAs) are rare, but life-threatening disorders characterized by microangiopathic hemolytic anemia and thrombocytopenia (MAHAT) associated with multiorgan dysfunction as a result of microvascular thrombosis and tissue ischemia. The differentiation of the etiology is of utmost importance as the pathophysiological basis will dictate the choice of appropriate treatment.We retrospectively evaluated 154 (99 females and 55 males) patients who received therapeutic plasma exchange (TPE) due to a presumptive diagnosis of TMA, who had serum ADAMTS13 activity/anti-ADAMTS13 antibody analysis at the time of hospital admission. The median age of the study cohort was 36 (14-84). 67 (43.5%), 32 (20.8%), 27 (17.5%) and 28 (18.2%) patients were diagnosed as thrombotic thrombocytopenic purpura (TTP), infection/complement-associated hemolytic uremic syndrome (IA/CA-HUS), secondary TMA and TMA-not otherwise specified (TMA-NOS), respectively. Patients received a median of 18 (1­75) plasma volume exchanges for 14 (153) days. 81 (52.6%) patients received concomitant steroid therapy with TPE. Treatment responses could be evaluated in 137 patients. 90 patients (65.7%) achieved clinical remission following TPE, while 47 (34.3%) patients had non-responsive disease. 25 (18.2%) non-responsive patients died during follow-up. Our study present real-life data on the distribution and follow-up of patients with TMAs who were referred to therapeutic apheresis centers for the application of TPE.  相似文献   
73.

Purpose

Cardiovascular disease (CVD) due to atherosclerosis is the leading cause of early mortality and morbidity. The current European guidelines on CVD prevention in clinical practice recommend the use of the Systematic Coronary Risk Estimation (SCORE) system. The current American Heart Association guidelines recommend the use of the new pooled cohort risk assessment equations to estimate the 10-year atherosclerotic CVD risk. The purpose of this article was to investigate the compliance of dyslipidemia guidelines in daily practice in patients with dyslipidemia or who have risk factors for CVD.

Methods

The study group consisted of 500 outpatients who had dyslipidemia or risk factors for CVD. The risk level was computed according to the European and American Heart Association guidelines. Therapeutic LDL-C targets were identified based on the calculated risk level. Therapeutic target levels were compared based on the dosage of statins used and achievement of the LDL-C goal in daily practice according to the risk levels.

Findings

According to the European dyslipidemia guidelines, 231 patients were in the very-high/high-risk group, and 106 patients (45.9%) achieved the LDL-C target (<100 mg/dL); 210 patients were in the moderate-risk group, and 156 (74.3%) patients achieved the LDL-C target (<115 mg/dL); and 59 patients were in the low-risk group, and 55 (93.2%) patients achieved the LDL-C target (<155 mg/dL). Univariate and multivariate logistic regression analyses revealed that the LDL-C level and presence of coronary artery disease were significantly reverse associated with achievement of the LDL-C goal (both, P < 0.001).

Implications

Our results showed that the majority of patients were in the very-high/high-risk group in daily practice. Although the European dyslipidemia guidelines are more likely to be used in daily practice, achievement of the guidelines-recommended treatment goals was low.  相似文献   
74.
75.
Pituitary - Our aim was to investigate the changes in the composition of oral and gut microbiota in patients with newly diagnosed acromegaly and their relationship with IGF-1 levels. Oral and fecal...  相似文献   
76.
Purpose

Hypophysitis is a heterogeneous condition that includes inflammation of the pituitary gland and infundibulum, and it can cause symptoms related to mass effects and hormonal deficiencies. We aimed to evaluate the potential role of machine learning methods in differentiating hypophysitis from non-functioning pituitary adenomas.

Methods

The radiomic parameters obtained from T1A-C images were used. Among the radiomic parameters, parameters capable of distinguishing between hypophysitis and non-functioning pituitary adenomas were selected. In order to avoid the effects of confounding factors and to improve the performance of the classifiers, parameters with high correlation with each other were eliminated. Machine learning algorithms were performed with the combination of gray-level run-length matrix-low gray level run emphasis, gray-level co-occurrence matrix-correlation, and gray-level co-occurrence entropy.

Results

A total of 34 patients were included, 17 of whom had hypophysitis and 17 had non-functioning pituitary adenomas. Among the 38 radiomics parameters obtained from post-contrast T1-weighted images, 10 tissue features that could differentiate the lesions were selected. Machine learning algorithms were performed using three selected parameters; gray level run length matrix-low gray level run emphasis, gray-level co-occurrence matrix-correlation, and gray level co-occurrence entropy. Error matrices were calculated by using the machine learning algorithm and it was seen that support vector machines showed the best performance in distinguishing the two lesion types.

Conclusions

Our analysis reported that support vector machines showed the best performance in distinguishing hypophysitis from non-functioning pituitary adenomas, emphasizing the importance of machine learning in differentiating the two lesions.

  相似文献   
77.
Summary.  Chronic delta hepatitis is the most severe form of chronic viral hepatitis for which interferon (IFN) is the only available treatment. In 39 patients (25 were treatment-naïve, 14 had previously used IFN), efficacy of 1-year treatment with IFN (9 MU, t.i.w.) or lamivudine (LAM; 100 mg, q.d.) alone was compared with IFN and LAM combination (2 months of LAM to be followed by combination treatment). IFN monotherapy was given only to treatment-naïve patients. In both treatment-naïve and previous IFN users, end of treatment virological and biochemical responses were similar with IFN–LAM combination and superior to LAM monotherapy ( P  < 0.05). Improvement in liver histology occurred more often with IFN ± LAM than with LAM alone ( P  < 0.05). In treatment-naïve patients, combination treatment was not superior to IFN monotherapy. After treatment discontinuation, virological and biochemical response rates decreased in LAM and IFN combination and IFN monotherapy. On treatment virological response at month 6 of treatment predicted sustained virological response. The results of this study suggest that addition of LAM to IFN for the treatment of delta hepatitis is of no additional value and that both treatment modalities are superior to LAM monotherapy.  相似文献   
78.
Hyperhomocysteinemia has been identified as independent risk factor for early atherosclerotic vascular disease. The purpose of our study was to investigate the plasma homocystein (Hcy) concentrations and its relationship with lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and nitric oxide (NOx; nitrite plus nitrate) concentrations in age-matched non-obese (n=55) and obese (n=60) female subjects with type 2 diabetes mellitus. Non-obese diabetic patients have significantly higher plasma tHcy and TBARS (p<0.001 and p<0.001), and significantly lower NOx concentrations than the controls (n=25) (p<0.001). The plasma tHcy and TBARS concentrations were higher and nitric oxide concentrations were lower in obese diabetics than in non-obese diabetics (for each comparison; p<0.001). Correlation analysis demonstrated that there was a significant positive correlation between tHcy and TBARS (r=0.452, p<0.01) in diabetics groups. There was no significant correlation between tHcy and plasma NOx, insulin and blood pressure. We thought that Hcy might have a permissive role on the endothelium damage through free radical generating systems and the presence of obesity the free radical induced-damage has been elevated in diabetic patients.  相似文献   
79.
BACKGROUND/AIMS: IPMT (intraductal papillary-mucinous tumor) of the pancreas has unique clinicopathological characteristics. The lesions which show characteristic clinical features of IPMT exhibit a wide spectrum of histological types ranging from atypical hyperplasia to invasive cancer. Therefore, surgical treatment cannot be recommended for all patients with IPMT. It is necessary to assess the malignant potential of IPMT in individual patients in order to select an appropriate approach. The aim of this study was to evaluate the effectiveness of endoscopic ultrasonography and intraductal ultrasonography as compared with ultrasonography and computed tomography for this purpose. METHODOLOGY: Ultrasonography, computed tomography, endoscopic ultrasonography and intraductal ultrasonography were performed in 49 cases of IPMT (atypical hyperplasia 7, adenoma 23, noninvasive 7 and invasive adenocarcinoma 12). On the basis of the histopathological analysis of another 28 cases of resected IPMT specimens, criteria for differential diagnosis by imaging modalities were defined as follows: Nonneoplastic lesion (atypical hyperplasia): no wall thickening or nodule; noninvasive IPMT (adenoma and intraductal carcinoma): a nodule or wall thickening is present; and invasive IPMT with pancreatic parenchymal invasion: a mass with a heterogenous pattern or interruption of the pancreatic duct wall by the mass. RESULTS: The diagnostic accuracy rate for differentiating nonneoplastic lesion noninvasive IPMT, and invasive IPMT was 33% by ultrasonography, 38% by computed tomography, 77% by endoscopic ultrasonography, and 67% by intraductal ultrasonography. Sensitivity, specificity and accuracy rates for differentiating neoplastic and nonneoplastic IPMT by ultrasonography was 33%, 100%, 42%, by computed tomography 36%, 100%, 44%, by endoscopic ultrasonography 90%, 71%, 88%, by intraductal ultrasonography 94%, 29%, 84%, respectively. Sensitivity, specificity and accuracy rates for differentiating invasive and noninvasive IPMT by ultrasonography was 25%, 100%, 80%, by computed tomography 33%, 100%, 83%, by endoscopic ultrasonography 55%, 97%, 88%, by intraductal ultrasonography 56%, 91%, 84%, respectively. Diagnostic accuracy for invasive IPMT except minimally invasive cases by endoscopic ultrasonography and intraductal ultrasonography was 80%, based on the results of the examination which demonstrated a higher grade lesion. CONCLUSIONS: With these criteria, ultrasonography and computed tomography showed high specificity, but low sensitivity for the differential diagnosis of neoplastic/nonneoplastic and invasive/noninvasive IPMT. However, endoscopic ultrasonography and intraductal ultrasonography had high sensitivity and diagnostic accuracy for the differential diagnosis of neoplastic/nonneoplastic lesions. Combination of endoscopic ultrasonography and intraductal ultrasonography showed a high accuracy rate in the diagnosis of invasive IPMT. Thus endoscopic ultrasonography and intraductal ultrasonography contributed significantly to the choice of the treatment for IPMT.  相似文献   
80.
Adult respiratory distress syndrome (ARDS) complicating the course of fulminant hepatic failure is nearly always fatal without orthotopic liver transplantation. We report the case of a 50-year-old woman with fulminant hepatic failure and ARDS that resolved after her recovery from the acute liver failure without liver transplantation. The pathogenesis is discussed, particularly with regard to liver-lung interactions.  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