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   2266篇
  免费   110篇
  国内免费   14篇
耳鼻咽喉   8篇
儿科学   20篇
妇产科学   36篇
基础医学   219篇
口腔科学   98篇
临床医学   143篇
内科学   595篇
皮肤病学   33篇
神经病学   79篇
特种医学   95篇
外科学   537篇
综合类   31篇
预防医学   28篇
眼科学   30篇
药学   173篇
中国医学   9篇
肿瘤学   256篇
  2023年   12篇
  2022年   21篇
  2021年   43篇
  2020年   23篇
  2019年   37篇
  2018年   44篇
  2017年   27篇
  2016年   59篇
  2015年   43篇
  2014年   67篇
  2013年   66篇
  2012年   136篇
  2011年   165篇
  2010年   99篇
  2009年   64篇
  2008年   128篇
  2007年   145篇
  2006年   138篇
  2005年   155篇
  2004年   158篇
  2003年   129篇
  2002年   155篇
  2001年   47篇
  2000年   40篇
  1999年   55篇
  1998年   33篇
  1997年   31篇
  1996年   28篇
  1995年   17篇
  1994年   17篇
  1993年   13篇
  1992年   16篇
  1991年   11篇
  1990年   20篇
  1989年   19篇
  1988年   17篇
  1987年   12篇
  1986年   5篇
  1985年   12篇
  1984年   14篇
  1983年   10篇
  1982年   6篇
  1981年   3篇
  1980年   6篇
  1979年   9篇
  1978年   7篇
  1977年   3篇
  1975年   4篇
  1974年   10篇
  1973年   3篇
排序方式: 共有2390条查询结果,搜索用时 46 毫秒
61.
62.
AIM: To investigate the clinical outcome of double balloon enteroscopy (DBE)-assisted endoscopic retrograde cholangiopancreatography (DB-ERCP) in patients with altered gastrointestinal anatomy.METHODS: Between September 2006 and April 2011, 47 procedures of DB-ERCP were performed in 28 patients with a Roux-en-Y total gastrectomy (n = 11), Billroth II gastrectomy (n = 15), or Roux-en-Y anastomosis with hepaticojejunostomy (n = 2). DB-ERCP was performed using a short-type DBE combined with several technical innovations such as using an endoscope attachment, marking by submucosal tattooing, selectively applying contrast medium, and CO2 insufflations.RESULTS: The papilla of Vater or hepaticojejunostomy site was reached in its entirety with a 96% success rate (45/47 procedures). There were no significant differences in the success rate of reaching the blind end with a DBE among Roux-en-Y total gastrectomy (96%), Billroth II reconstruction (94%), or pancreatoduodenectomy (100%), respectively (P = 0.91). The total successful rate of cannulation and contrast enhancement of the target bile duct in patients whom the blind end was reached with a DBE was 40/45 procedures (89%). Again, there were no significant differences in the success rate of cannulation and contrast enhancement of the target bile duct with a DBE among Roux-en-Y total gastrectomy (88 %), Billroth II reconstruction (89%), or pancreatoduodenectomy (100%), respectively (P = 0.67). Treatment was achieved in all 40 procedures (100%) in patients whom the contrast enhancement of the bile duct was successful. Common endoscopic treatments were endoscopic biliary drainage (24 procedures) and extraction of stones (14 procedures). Biliary drainage was done by placement of plastic stents. Stones extraction was done by lithotomy with the mechanical lithotripter followed by extraction with a basket or by the balloon pull-through method. Endoscopic sphincterotomy was performed in 14 procedures with a needle precutting knife using a guidewire. The mean total duration of the procedure was 93.6 ± 6.8 min and the mean time required to reach the papilla was 30.5 ± 3.7 min. The mean time required to reach the papilla tended to be shorter in Billroth II reconstruction (20.9 ± 5.8 min) than that in Roux-en-Y total gastrectomy (37.1 ± 4.9 min) but there was no significant difference (P = 0.09). A major complication occurred in one patient (3.5%); perforation of the long limb in a patient with Billroth II anastomosis.CONCLUSION: Short-type DBE combined with several technical innovations enabled us to perform ERCP in most patients with altered gastrointestinal anatomy.  相似文献   
63.
ObjectiveThe objective was to examine the effects of colestimide on blood glucose, visceral fat, adipocytokines, and bile acid conjugate fractions in Japanese patients.MethodsThis study was an open-label, randomized, case–control, crossover study of colestimide 3 g/day in 40 Japanese patients with type 2 diabetes mellitus (T2D) and hypercholesterolemia. Patients were assigned to the colestimide group in which pravastatin and colestimide were administered orally and to the statin group in which pravastatin alone was administered orally. The principal outcome measures were serum lipid levels, fasting plasma glucose level in the early morning, hemoglobin A1c (HbA1c), visceral fat area (VFA), and serum 1,5-anhydroglucitol (1,5-AG) level.ResultsSerum low-density lipoprotein cholesterol levels significantly decreased from 113±38 mg/dl at baseline to 90±20 mg/dl (P=.009) at week 12 of colestimide administration. HbA1c significantly decreased from 7.4%±0.9% at baseline to 6.9%±0.9% (P=.001) at week 12 of colestimide administration. Serum 1,5-AG levels increased from 9.4±10.1 μg/ml to 12.4±9.5 μg/ml (P=.05) at week 12 of colestimide administration. The statin group showed no significant changes in lipids and 1,5-AG. However, ΔVFA was inversely correlated with Δcholic acid, and multivariate analysis revealed that ΔVFA was a significant explanatory variable.ConclusionsColestimide holds promise not only for the treatment of hypercholesterolemia but also for the possible improvement of T2D and visceral fat obesity.  相似文献   
64.
65.
Aim: Although several studies have reported various causes of ischemic stroke in patients with cancer, only a few have evaluated the clinical relevance of ischemic stroke pathogenesis to cancer. The aim of the present study was to elucidate the clinical characteristics of cancer‐associated ischemic stroke. Methods: We evaluated 154 ischemic stroke patients without cancer and 57 ischemic stroke patients with cancer who had either received continuous treatment for cancer within 5 years before to the onset of ischemic stroke, or who had been diagnosed with cancer within 1 year after the onset of ischemic stroke. Cancer patients were grouped into “cancer‐associated ischemic stroke,” the “conventional ischemic stroke,” or “other.” Results: A total of 15 patients (26%) were classified into the cancer‐associated ischemic stroke in cancer patients. In univariate analysis of the cancer‐associated ischemic stroke and the others, there were significant differences in the prevalence of hypertension, hyperlipidemia and advanced cancer (clinical stage IV), and the levels of d ‐dimer, fibrin degradation product and hemoglobin. With multivariate regression analysis of those factors, the prevalence of hypertension, hyperlipidemia and advanced cancer (clinical stage IV), and the levels of d ‐dimer and fibrin degradation product remained as statistically independent factors, which were associated with cancer‐associated ischemic stroke (n = 111, χ2 = 67.21, P < 0.0001). Conclusion: In acute ischemic stroke, the cancer‐associated ischemic stroke is associated with elevated d ‐dimer and fibrin degradation products, even after controlling hypertension, hyperlipidemia and advanced cancer (clinical stage IV). Geriatr Gerontol Int 2012; 12: 468–474.  相似文献   
66.

Purposes

The purpose of this study was to show the clinical features of up-front surgery of the primary tumor in asymptomatic patients with incurable colorectal PC.

Methods

Forty-six patients that were diagnosed between 1998 and 2007 with asymptomatic colorectal PC who could not be successfully cured by surgery were assessed retrospectively.

Results

A univariate analysis revealed the presence of liver metastases, without the use of oxaliplatin (OX)/irinotecan (IRI) and without a primary tumor resection to be poor prognostic factors for survival (p = 0.044, p = 0.030, p < 0.001, respectively). According to a multivariate analysis, no use of OX/IRI and no primary tumor resection, were found to be independent poor prognostic factors for survival (HR 2.57; p = 0.047, HR 6.62; p = 0.003, respectively). The median survival time of patients treated with and without OX/IRI was 18 and 7 months, respectively. The median survival time of patients with and without primary tumor resection was 10 and 2 months, respectively. The number of patients needing surgical intervention for intestinal obstruction after surgery significantly increased in patients treated with OX/IRI (p = 0.001).

Conclusion

Improvement of survival may be related to widespread use of modern systemic chemotherapy and primary tumor resection. However, an increased number of patients that needed surgery for an intestinal obstruction were observed, even after up-front surgery, when patients were treated with modern systemic chemotherapy.  相似文献   
67.

Background

The significance of perineural invasion in extrahepatic cholangiocarcinoma has not been fully elucidated. This study aims to determine the prognostic impact of and optimal treatment strategy for perineural invasion in patients with extrahepatic cholangiocarcinoma.

Methods

Medical records of 133 patients with extrahepatic cholangiocarcinoma who underwent curative resection were reviewed retrospectively. Ninety-eight patients had perineural invasion and 35 patients did not. Univariate and multivariate survival analyses were performed to clarify the prognostic impact of and optimal treatment strategy for perineural invasion.

Results

Only tumor differentiation (P?=?0.024) was independently associated with perineural invasion in the multivariate logistic regression model. Multivariate survival analysis revealed that perineural invasion (P?=?0.002), resection margin status (P?=?0.016), and International Union Against Cancer (UICC) pT factor (P?=?0.015) were independent prognostic factors of overall survival. Overall 5-year survival rates for patients with and without perineural invasion were 28 and 74 %, respectively. Among 98 patients with perineural invasion, the use of adjuvant chemotherapy (P?=?0.003), lymph node status (P?=?0.015), resection margin status (P?=?0.008), and UICC pT factor (P?=?0.016) were independently associated with overall survival by multivariate analysis. Overall 5-year survival rates for patients with perineural invasion who did and did not receive adjuvant chemotherapy were 33 and 21 %, respectively (P?=?0.023).

Conclusions

Perineural invasion is a potent prognostic factor in extrahepatic cholangiocarcinoma. Adjuvant chemotherapy may improve the overall survival of patients with perineural invasion.  相似文献   
68.
69.
The effects of acupuncture stimulation to the sacral segment on electroencephalograms (EEGs) and activity of locus coeruleus (LC) neurons were examined in urethane-anesthetized rats. In 71 of 112 trials, when EEGs displayed small amplitude and high frequency, stimulation to the sacral segment-induced large amplitude and slow EEGs with a latency of <450s and duration ranged from 32s to >42 min. Stimulus-induced EEGs comprised significant increases in delta power and significant decreases in theta and beta powers. After intraperitoneal administration of bicuculline, stimulation to the sacral segment failed to induce changes in EEG pattern. Firing rate of noradrenergic LC neurons decreased significantly from 2.9+/-1.5 to 1.1+/-0.8 Hz (n=11, p<0.001). Decreased neuronal activity exhibited close relationships with increased EEG amplitude. These results suggest that acupuncture stimulation to the sacral segment changes the state of animals from light anesthesia to deep anesthesia, and that this change is mediated by GABAergic systems suppressing the activity of noradrenergic LC neurons.  相似文献   
70.
The aim of this multi-center study was to explore the relationship between missing occlusal units and oral health-related quality of life (OHRQoL) in subjects with the shortened dental arches (SDAs). Subjects with SDAs were recruited consecutively for one month from six university-based prosthodontic clinics. In total, 115 SDA subjects participated (mean age, 58.5 +/- 10.0 yrs; 71% female). The location and number of missing teeth were examined and the number of missing occlusal units was calculated. To evaluate OHRQoL, the Japanese version of the Oral Health Impact Profile (OHIP-J) was administered and the summary score of OHIP-J was calculated. The SDA subjects were categorized depending upon the anterior-posterior lengths of the missing or remaining occlusal units. Regression analyses were performed to investigate 1) the association between missing OU and OHIP-J summary scores and 2) the OHIP-J differences between groups of subjects with various anterior-posterior SDA lengths. The first analyses revealed that one missing OU was significantly related to an increase of 2.1 OHIP-J units (95% CI: 0.6-3.5, P=0.016). The second analysis revealed that subjects who only lost the second molar contact exhibited significantly better OHRQoL than those who lost more teeth (Coefficient: 11.1, 95% CI: 2.8-19.2, P=0.02). Furthermore a statistically significant group difference was observed between the groups with and without the first molar occlusal contact (Coefficient: 12.8, 95% CI: 1.4 to 24.1, P=0.03). These results suggest that missing occlusal units are related to the OHRQoL impairment in subjects with SDAs. They also suggest that the patterns of missing occlusal units are likely to be related to the OHRQoL impairment in SDA subjects with the presence of first molar contact having an important role.  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