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   2234篇
  免费   131篇
  国内免费   29篇
耳鼻咽喉   42篇
儿科学   41篇
妇产科学   38篇
基础医学   305篇
口腔科学   26篇
临床医学   136篇
内科学   595篇
皮肤病学   24篇
神经病学   136篇
特种医学   47篇
外科学   465篇
综合类   11篇
一般理论   2篇
预防医学   50篇
眼科学   23篇
药学   143篇
中国医学   3篇
肿瘤学   307篇
  2023年   34篇
  2022年   44篇
  2021年   72篇
  2020年   34篇
  2019年   47篇
  2018年   57篇
  2017年   63篇
  2016年   67篇
  2015年   61篇
  2014年   87篇
  2013年   104篇
  2012年   159篇
  2011年   173篇
  2010年   76篇
  2009年   55篇
  2008年   88篇
  2007年   128篇
  2006年   131篇
  2005年   135篇
  2004年   139篇
  2003年   103篇
  2002年   106篇
  2001年   37篇
  2000年   35篇
  1999年   37篇
  1998年   13篇
  1997年   14篇
  1996年   23篇
  1995年   12篇
  1994年   17篇
  1993年   12篇
  1992年   21篇
  1991年   14篇
  1990年   12篇
  1989年   10篇
  1988年   21篇
  1987年   14篇
  1986年   15篇
  1985年   14篇
  1984年   17篇
  1983年   6篇
  1982年   6篇
  1981年   7篇
  1980年   12篇
  1979年   8篇
  1977年   7篇
  1974年   6篇
  1972年   4篇
  1971年   4篇
  1969年   4篇
排序方式: 共有2394条查询结果,搜索用时 15 毫秒
81.

Background

The present study aimed to obtain information enabling optimisation of the clinical effect of mizoribine (MZR) in pediatric patients with kidney disease.

Methods

A total of 105 pediatric patients with kidney disease treated at our institutions were enrolled. Kidney transplant patients were excluded. Population pharmacokinetic analysis of MZR was performed based on serum concentration data. Area under the curve from time zero to infinity (AUC) and maximal concentration (C max) were calculated by Bayesian analysis.

Results

In children, the appearance of MZR in the blood tended to be slower and the subsequent rise in blood concentration tended to be more sluggish, compared to healthy adults. Apparent volume of distribution and oral clearance were also higher in children compared to adults. A significant positive correlation was observed between patient age and AUC. There were significant differences of AUC and C max by age group. No relationship was observed between the administration method of MZR and serum concentration.

Conclusion

The pharmacokinetics of MZR was different in children compared to adults. To obtain the expected clinical efficacy, the regular MZR dosage schedule (2–3 mg/kg/day) might be insufficient for pediatric patients. In particular, younger patients might require a higher dosage of MZR per unit body weight.
  相似文献   
82.
Type I interferons (IFNs), IFN-alpha and IFN-beta, are widely used for treating chronic hepatitis C. Although retrospective studies have suggested that type I IFNs have direct antifibrotic effects, little is known about these mechanisms. The present study was designed to clarify the preventive mechanisms of type I IFNs in the progression of fibrosis for the establishment of a more effective therapy. A murine fibrosis model comprising immunological reactions was induced by the administration of concanavalin A (0.3 mg/body) into mice once a week for 4 weeks. Liver injury and the degree of fibrosis were determined by measuring the serum alanine aminotransferase activities and liver hydroxyproline contents with or without IFN-beta pretreatment. IFN-beta suppressed the hepatocellular injury and increased the hydroxyproline content induced by repeated concanavalin A injections, but had no effect on established fibrosis. Furthermore, IFN-beta reduced the expressions of transforming growth factor-beta, basic fibroblast growth factor, collagen type I A2 and tissue inhibitor of metalloproteinase 1 messenger RNAs, which are related to the progression of liver fibrosis. The IFN-beta reduced the liver injury and fibrosis induced by immunological reactions. These data suggest that type I IFNs suppress the progression of cirrhosis through inhibition of repeated hepatocellular injury and/or factors that promote the liver fibrosis induced by hepatitis virus infection.  相似文献   
83.
Doppel (Dpl) is a prion protein paralog that causes neurodegeneration when expressed ectopically in the brain. To investigate the cellular mechanism underlying this effect, we analyzed Dpl-expressing transgenic mice in which the gene for the proapoptotic protein Bax had been deleted. We found that Bax deletion does not alter either clinical symptoms or Purkinje cell degeneration in Dpl transgenic mice. In addition, we observed that degenerating Purkinje cells in these animals do not display DNA fragmentation or caspase-3 activation. Our results suggest that non-Bax-dependent pathways mediate the toxic effects of Dpl in Purkinje cells, highlighting a possible role for nonapoptotic mechanisms in the death of these neurons.  相似文献   
84.
Orengedokuto is a Kampo formula that has been used for removing “heat” and “poison” to treat inflammation, hypertension, gastrointestinal disorders, and liver and cerebrovascular diseases. We report here our analysis of the anti-inflammatory effect of the component crude drugs of orengedokuto and their constituents using the inhibition of nitric oxide (NO) production in the murine macrophage-like cell line J774.1. An initial comparison of NO production inhibitory activities of the extracts of the component crude drugs and their combinations revealed that the activity could be attributed to Phellodendron Bark and Coptis Rhizome. Berberine (1), the major constituent of these crude drugs, showed potent activity (IC50 4.73?±?1.46 μM). Quantitative analysis of 1 in the extracts of all combinations of component crude drugs revealed that the amount of 1 in each extract of the combination of Scutellaria Root with either Phellodendron Bark and/or Coptis Rhizome was lower than that in the corresponding mixtures of the extracts of the individual crude drugs and that 1 was present in the precipitates formed during the decoction process. To the contrary, the differences in the amounts of 1 were smaller in the extracts containing Gardenia Fruit. These results indicated that the constituents of Scutellaria Root precipitated with 1 and that the constituents of Gardenia Fruit dissolved the precipitates. To identify the constituents affecting the solubility of 1, we fractionated the hot-water extracts of Scutellaria Root based on solubility tests of 1 to give baicalin (2), wogonin (3) and oroxyloside (4), which formed precipitates with 1.  相似文献   
85.
Journal of Natural Medicines - Scutellaria root, the root of Scutellaria baicalensis Georgi, is a crude drug used for inflammatory diseases. In our previous report, the combination of flavonoids...  相似文献   
86.
World Journal of Surgery - Gastric cancers located within the upper-third of the stomach (UGC), especially the esophagogastric junction GC (EGJGC), have distinct clinicopathological features due to...  相似文献   
87.

Purpose

Since 2000, the incidence of ulcerative colitis (UC) in patients over 60 years old has been rapidly increasing. We reviewed our surgical experience of elderly patients with UC treated at our hospital.

Methods

Patients aged 60 years or older at the time of surgery were defined as “elderly”. The medical records of all elderly patients who underwent surgery for UC during a 26-year period were retrospectively analyzed.

Results

The prognosis of elderly patients who underwent emergency surgery was extremely poor: 8 (26.7 %) of 30 such patients died within 30 postoperative days (PODs), whereas only 1 (0.88 %) of 114 who underwent elective surgery died within 30 PODs. Respiratory tract infection and sepsis resulting from methicillin-resistant Staphylococcus aureus or mycotic infection were the most common causes of death after emergency surgery.

Conclusion

The prognosis of elderly UC patients undergoing emergency surgery is very poor; thus, physicians and surgeons should collaborate to treat severe and fulminant disease, to optimize the timing of surgery. Early decisions about emergency surgery for UC will reduce postoperative mortality, especially in elderly patients.  相似文献   
88.
ObjectiveTo evaluate the effect of body mass index (BMI) on the outcomes of patients with urinary tract carcinoma treated with radical surgery.Materials and methodsData were collected from 10 Canadian centers on patients who underwent radical cystectomy (RC) (1998–2008) or radical nephroureterectomy (RNU) (1990–2010). Various parameters among subsets of patients (BMI<25, 25≤BMI<30, and BMI≥30 kg/m2) were analyzed. Kaplan-Meier and multivariate analyses were performed to assess the effect of BMI on overall survival, disease-specific survival, and recurrence-free survival (RFS).ResultsAmong the 847 RC and 664 RNU patients, there was no difference in histology, stage, grade, and margin status among the 3 patient subsets undergoing either surgery. However, RC patients with lower BMIs (<25 kg/m2) were significantly older (P = 0.004), had more nodal metastasis (P = 0.03), and trended toward higher stage (P = 0.052). RNU patients with lower BMIs (<25 kg/m2) were significantly older (P = 0.0004) and fewer received adjuvant chemotherapy (P = 0.04) compared with those with BMI≥30 kg/m2; however, there was no difference in tumor location (P = 0.20), stage (P = 0.48), and management of distal ureter among the groups (P = 0.30). On multivariate analysis, BMI was not prognostic for overall survival, disease-specific survival, and RFS in the RC group. However, BMI≥30 kg/m2 was associated with more bladder cancer recurrences and worse RFS in the RNU group (HR = 1.588; 95% CI: 1.148–2.196; P = 0.0052).ConclusionsIncreased BMI did not influence survival among RC patients. BMI≥30 kg/m2 is associated with worse bladder cancer recurrences among RNU patients; whether this is related to difficulty in obtaining adequate bladder cuff in patients with obesity requires further evaluation.  相似文献   
89.
Rational treatment for neoplasms of the duodenal papilla (NDPs) is still controversial, especially for early stage lesions. Total papillectomies are indicated in patients expected to have adenomas, adenocarcinoma in an adenoma, or mucosal adenocarcinomas with no lymph node metastases. However, the preoperative pathological evaluation of NDPs is still challenging and often inaccurate, mainly because of the complicated anatomical structures involved and the possibility of an adenocarcinoma in an adenoma. Herein, we introduce a new method of total papillectomy, the extraduodenal papillectomy (ExDP). In this method, papillectomy is undertaken from outside of the duodenum, instead of resection from the inside through a wide incision of the duodenal wall as is done in conventional transduodenal papillectomy (TDP). The advantages of ExDP are precise and deeper cutting of the sphincter and shorter exploration time of the tumor compared to conventional TDP. We demonstrate three representative patients, all of whom had an uneventful postoperative course. One of them subsequently underwent a pylorus preserving pancreatoduodenectomy after detailed postoperative pathological evaluation. Including that patient, no recurrence has occurred with 37–46 months of follow-up. In conclusion, ExDP is regarded as a “total biopsy” for early stage borderline lesions and a feasible, less demanding alternative method for the treatment of NDPs.  相似文献   
90.
BackgroundThe incidence rate of kinking of the middle lobe bronchus following right upper lobectomy is higher compared to that with residual lung bronchus following other lobectomies. Bronchial kinking was presumed to be caused by the displacement of the residual lung lobes, but its etiology is unclear. Moreover, prevention methods and effective treatments have not yet been established. The purpose of this study was to investigate the risk factors and etiology of middle lobe bronchus kinking and discuss prevention methods.MethodsPatients who underwent right upper lobectomy in our hospital were retrospectively evaluated. Patient clinical characteristics, lung function, and lung lobe volume, surgical procedure were analyzed in association with the incidence of middle lobe bronchus kinking. The association between the displacement of residual lung lobes after operation and the incidence of middle lobe bronchus kinking was analyzed to assess the etiology.ResultsA total of 175 patients were enrolled in the risk analysis. Middle lobe bronchus kinking was observed in 5 patients (2.9%). The low percentage of forced expiratory volume percentage in 1 second (P=0.021), the low volume ratio of the right middle lobe (RML) to the right thoracic cavity (RTC) (P=0.016), and the low volume ratio of RML to right upper lobe (RML/RUL) (P=0.006) were significant risk factors of middle lobe bronchus kinking. In the patients who underwent CT at 6 months after surgery, the degree of the cranial displacement of RML was associated with the incidence of middle lobe bronchus kinking (P=0.025).ConclusionsThe risk of middle lobe bronchus kinking could be assessed preoperatively by calculating the volume ratio of RML/RTC and RML/RUL. The displacement of RML could be associated with the incidence of middle lobe bronchus kinking.  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