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   3109篇
  免费   178篇
  国内免费   12篇
耳鼻咽喉   60篇
儿科学   48篇
妇产科学   20篇
基础医学   302篇
口腔科学   51篇
临床医学   183篇
内科学   730篇
皮肤病学   29篇
神经病学   174篇
特种医学   96篇
外科学   918篇
综合类   17篇
预防医学   87篇
眼科学   60篇
药学   137篇
中国医学   4篇
肿瘤学   383篇
  2023年   22篇
  2022年   40篇
  2021年   65篇
  2020年   54篇
  2019年   60篇
  2018年   60篇
  2017年   70篇
  2016年   64篇
  2015年   77篇
  2014年   101篇
  2013年   97篇
  2012年   143篇
  2011年   183篇
  2010年   92篇
  2009年   102篇
  2008年   174篇
  2007年   133篇
  2006年   128篇
  2005年   124篇
  2004年   107篇
  2003年   113篇
  2002年   131篇
  2001年   92篇
  2000年   79篇
  1999年   86篇
  1998年   39篇
  1997年   35篇
  1996年   35篇
  1995年   38篇
  1994年   31篇
  1993年   18篇
  1992年   59篇
  1991年   76篇
  1990年   83篇
  1989年   68篇
  1988年   67篇
  1987年   60篇
  1986年   62篇
  1985年   46篇
  1984年   43篇
  1983年   41篇
  1982年   9篇
  1981年   9篇
  1979年   20篇
  1978年   12篇
  1977年   13篇
  1975年   3篇
  1972年   3篇
  1967年   4篇
  1966年   9篇
排序方式: 共有3299条查询结果,搜索用时 31 毫秒
81.
We investigated the role of insulin receptor substrate (Irs)‐1 for diethylnitrosamine (DEN) plus high‐fat (HF) diet‐induced hepatic tumorigenesis in mice. We gave DEN by intraperitoneal injection at the dose of 80 mg/kg to 18‐week‐old wild‐type (WT) and Irs1‐knockout (Irs1−/−) mice, which were fed a HF diet from 8 weeks‐of‐age until they were killed (52 weeks). The Irs1−/− mice showed significantly lower plasma alanine aminotransferase levels, triglyceride contents in the liver and also lower expression levels of the genes encoding inflammatory cytokines than the WT mice. The incidence of DEN plus HF diet‐induced hepatic tumors was 71.4% in the WT mice, whereas it was just 14.3% in the Irs1−/− mice. The present study showed that Irs1 played an important role in DEN plus HF diet‐induced hepatic tumorigenesis.  相似文献   
82.
83.
We report a rare case of bleeding duodenal ulceration in the different form of pemphigus vulgaris (PV). A 52-year-old female was diagnosed with acute pharyngitis and administered methylprednisolone. After several days, melena and many blisters were noted on her body. Endoscopy revealed blood oozing from the second part of a duodeneal ulcer around the major duodenal papilla. After initial endoscopic hemostasis, we observed a large regional, shallow duodenal ulcer. The blisters were suspected to represent the Nikolsky’s sign. The histological findings of her skin were characterized by suprabasal acantholysis and mixed inflammatory cell infiltrates, including scattered eosinophils. There were no other significant findings on skin biopsy or by direct immunofluorescence. Enzyme-linked immunosorbent assay showed an elevated titer of anti-desmoglein 3 autoantibodies in her serum, and the patient was finally diagnosed with mucosal-dominant PV. Although we performed multiple biopsies from the esophagus, stomach and duodenum, the samples did not contain significant findings to enable us to distinguish from pemphigus vulgaris. Corticosteroids remain an essential component of PV treatment. When clinicians encounter PV development during steroid therapy, upper gastrointestinal complications should be considered and diagnostic endoscopy conducted.  相似文献   
84.
A 44-year-old male was pointed out liver function abnormality by medical check-up. Blood examination and computed tomography showed liver cirrhosis. Then, he was referred to our hospital for further examination. After blood test, viral markers revealed previous infection of hepatitis B virus (HBV). We estimated the etiology of his liver disease as previous HBV infection. On laparoscopic examination, his liver surface was nodular with mixed yellowish nodules and ash gray to copper-colored nodules in the diameter of 3–10 mm. There were large regenerative nodules in segments 3 and 4. Large regenerative nodules and irregular steatosis were contradictory to HBV-related liver cirrhosis, so then we supposed Wilson’s disease. The amount of copper excretion in the urine was 326.6 μg (>100 μg/24 h). After D-penicillamine administration, urinary copper excretion increased to 2151.5 μg/24 h. Though hepatic copper concentration was 174.5 μg/g wet tissue (>200 μg/g wet tissue), his laboratory data fulfilled the Leipzig diagnostic criteria proposed by EASL. Laparoscopic examination with liver biopsy has advantages to survey many disease-specific findings on liver surface and to obtain adequate liver sample. Laparoscopic examination is one of the effective procedures for diagnosing relatively rare liver disease like Wilson’s disease.  相似文献   
85.
Background/Aims: In patients with septic shock, the degree of liver dysfunction is correlated with serum levels of soluble intercellular adhesion molecule (sICAM)-1. We aimed to assess the usefulness of serum levels of soluble adhesion molecules as prognostic factors for acute liver failure (ALF). Methods: Serum levels of soluble platelet endothelial cell adhesion molecule (sPECAM)-1, sICAM-3, soluble endothelial (sE) selectin, sICAM-1, soluble platelet selectin, and soluble vascular cell adhesion molecule-1 on admission were measured in 37 ALF patients and 34 healthy controls. Results: Twenty-two ALF patients (59%) reached to fatal outcomes. Serum levels of sPECAM-1, sICAM-3, sE-selectin and sICAM-1 were higher in ALF patients than healthy controls. In 37 ALF patients, by the multivariate logistic regression analysis, ratio of direct to total bilirubin (per 0.1 increase; OR 0.11, 95% CI 0.01-0.99), serum sPECAM-1 level (per 100 ng/ml increase; OR 4.37, 95% CI 1.23-15.5) and serum sICAM-1 level (per 100 ng/ml increase; OR 0.49, 95% CI 0.27-0.89) were associated with fatal outcomes. Using receiver operating characteristics curve, each area under the curve of serum sPECAM-1 and sICMA-1 levels as prognostic factors was 0.71 and 0.74, respectively. Conclusion: Serum sPECAM-1 and sICAM-1 levels may be useful for predicting the prognosis of ALF.  相似文献   
86.
ObjectiveThis multicenter cross-sectional study aimed to investigate the clinical features and varieties of non-motor fluctuation in Parkinson's disease (PD).MethodsTo identify motor and non-motor fluctuation, we employed the wearing-off questionnaire of 19 symptoms (WOQ-19) in 464 PD patients. We compared the frequency of levodopa-related fluctuation as identified by the WOQ-19 with recognition by neurologists. We compared patients with both motor and non-motor fluctuations with those who only had motor fluctuations. Non-motor fluctuations were separated into psychiatric, autonomic, and sensory categories for further analysis.ResultsThe patients' average age was 70.8 ± 8.4 years (mean ± SD) and disease duration was 6.6 ± 5.0 years. The frequency of motor fluctuations was 69% and for non-motor fluctuation 40%. Fifty-three percent of patients with motor fluctuations also had non-motor fluctuations, whereas 93% of patients with non-motor fluctuations also had motor fluctuations. The WOQ-19 showed a sensitivity of 82% but a specificity of only 40%. The patients with both non-motor and motor fluctuations exhibited more severe motor symptoms, more non-motor symptoms and higher levodopa daily doses (p < 0.05). Patients had significantly higher fluctuation rates if they had psychiatric (49%) and sensory (45%) symptoms than patients with autonomic symptoms (32%, p < 0.01). Forty-eight percent of patients with non-motor fluctuations exhibited more than one type of non-motor fluctuation.ConclusionForty percent of PD patients presented with non-motor fluctuations, and almost half of these exhibited more than one type. Appropriate recognition of levodopa-related fluctuations, both motor and non-motor, can lead to treatment modifications in PD patients.  相似文献   
87.
88.
89.
AIM:To determine the effect of oral sumatriptan on gastric emptying using a continuous 13 C breath test(BreathID system).METHODS:Ten healthy male volunteers participated in this randomized,2-way crossover study.The subjects fasted overnight and were randomly assigned to receive a test meal(200 kcal/200 mL) 30 min after pre-medication with sumatriptan 50 mg(sumatriptan condition),or the test meal alone(control condition).Gastric emptying was monitored for 4 h after administration of the test meal by the 13 C-acetic acid breath test performed continually using the BreathID system.Then,using Oridion Research Software(β version),the time taken for emptying of 50% of the labeled meal(T 1/2) similar to the scintigraphy lag time for 10% emptying of the labeled meal(T lag),the gastric emptying coefficient(GEC),and the regression-estimated constants(β and κ) were calculated.The statistical significance of any differences in the parameters were analyzed using Wilcoxon’s signed-rank test.RESULTS:In the sumatriptan condition,significant differences compared with the control condition were found in T 1/2 [median 131.84 min(range,103.13-168.70) vs 120.27 min(89.61-138.25);P = 0.0016],T lag [median 80.085 min(59.23-125.89) vs 61.11 min(39.86-87.05);P = 0.0125],and β [median 2.3374(1.6407-3.8209) vs 2.0847(1.4755-2.9269);P = 0.0284].There were no significant differences in the GEC or κ between the 2 conditions.CONCLUSION:This study showed that oral sumatriptan significantly delayed gastric emptying of a liquid meal.  相似文献   
90.
Para‐aortic lymph node (PALN) recurrence is often seen in patients with lower thoracic esophageal cancer treated by esophagectomy with extended lymph node dissection. However, the clinicopathological characteristics of patients with PALN metastasis and the significance of PALN dissection are unknown. A total of 283 patients with lower thoracic esophageal cancer underwent esophagectomy with lymphadenectomy at our hospital between April 1984 and March 2007. Among these 283 patients, 60 patients were enrolled in this retrospective study according to following criteria: (i) clinical T2 to T4 tumor, (ii) no clinical PALN metastasis, and (iii) received PALN dissection. PALN dissection was indicated by a tumor depth of at least T2 and no severe complications. The clinicopathological data, recurrence pattern, and overall survival were compared between patients with PALN and without PALN metastasis. The mean length of surgery was 587 min and the mean blood loss was 1383 mL. The morbidity was 33.3% and mortality was 5% in this series. Sixteen patients (26.7%) had PALN metastasis; these showed significantly more lymph node metastases (15.8 ± 13.2 vs. 3.0 ± 3.2, P < 0.0001) and significantly worse survival rates (53.3% vs. 79.9% at 1 year, 6.7% vs. 62.0% at 3 years, P < 0.0001) than patients without PALN metastasis. The incidence of lymph node recurrence (P < 0.0001) and hematogenous recurrence (P= 0.0487) was also higher in patients with PALN metastasis than in patients without PALN metastasis. Among the 16 patients with PALN metastasis, a univariate analysis revealed total number of metastatic nodes < 8 (P= 0.0325) to be a significant prognostic factor. A multivariate logistic regression analysis of the regional lymph nodes identified the invasion of the lower mediastinal nodes (hazard ratio = 6.120) and retroperitoneal nodes (hazard ratio = 15.167) to be significantly correlated with PALN metastasis. PALN metastasis is suggested to be related to the systemic spread of lymphatic metastasis even in lower thoracic esophageal cancer. PALN dissection for pathological PALN(+) patients should not be performed. It remains to be determined in future prospective studies whether patients without pathological PALN metastasis, but showing PALN micrometastasis, could achieve improved survival with PALN dissection.  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