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   3865篇
  免费   168篇
  国内免费   50篇
耳鼻咽喉   9篇
儿科学   81篇
妇产科学   13篇
基础医学   432篇
口腔科学   69篇
临床医学   278篇
内科学   1227篇
皮肤病学   57篇
神经病学   199篇
特种医学   189篇
外科学   775篇
综合类   14篇
预防医学   65篇
眼科学   36篇
药学   222篇
中国医学   20篇
肿瘤学   397篇
  2023年   17篇
  2022年   48篇
  2021年   85篇
  2020年   49篇
  2019年   62篇
  2018年   91篇
  2017年   95篇
  2016年   92篇
  2015年   128篇
  2014年   148篇
  2013年   187篇
  2012年   255篇
  2011年   289篇
  2010年   174篇
  2009年   137篇
  2008年   212篇
  2007年   252篇
  2006年   223篇
  2005年   265篇
  2004年   246篇
  2003年   236篇
  2002年   217篇
  2001年   41篇
  2000年   29篇
  1999年   35篇
  1998年   36篇
  1997年   34篇
  1996年   38篇
  1995年   38篇
  1994年   23篇
  1993年   22篇
  1992年   13篇
  1991年   23篇
  1990年   20篇
  1989年   23篇
  1988年   18篇
  1987年   23篇
  1986年   24篇
  1985年   13篇
  1984年   11篇
  1983年   4篇
  1982年   10篇
  1981年   18篇
  1980年   15篇
  1979年   11篇
  1978年   4篇
  1977年   6篇
  1975年   8篇
  1974年   6篇
  1908年   3篇
排序方式: 共有4083条查询结果,搜索用时 15 毫秒
51.
52.
53.

Background

We previously demonstrated validation of the Comprehensive International Classification of Functioning, Disability and Health Core Set for Diabetes Mellitus (ICF-CS for DM) in patients with diabetic nephropathy (DMN). The objective of the present study was to identify differences in experience of physical and psychosocial problems between DMN patients with and without hemodialysis (HD), and diabetes patients without nephropathy using the ICF-CS for DM.

Methods

A total of 302 diabetes outpatients (men, 68 %; mean age, 62 years) were interviewed using four components of the ICF-CS for DM including “Body functions”, “Body structures”, “Activities and participation”, and “Environmental factors”.

Results

The mean number of categories in which difficulty was experienced in the four components was significantly greater in DMN patients with HD followed by DMN patients without HD, and diabetes patients without nephropathy (23.9 vs. 18.0 vs. 13.1, respectively). Multivariate logistic regression models revealed that, compared with diabetes patients without nephropathy, diabetes patients with nephropathy were more likely to have difficulty with physical problems and social activities and participation. Among DMN patients, dialysis patients were found to have larger numbers of problems, and face difficulty with employment status after adjusting for sex, age, type, and duration of diabetes.

Conclusion

The results of this study using the ICF-CS for DM identified the areas for improvement among physical and psychosocial problems in DMN patients with and without HD in contrast to diabetes patients without nephropathy.
  相似文献   
54.
A 64-year-old female was found to have localized ground-glass opacity (GGO) in the middle lobe on a chest computed tomography (CT) for screening. Middle lobectomy with video-assisted thoracoscopic surgery (VATS) was undertaken, and pathological diagnosis was a bronchioloalveolar carcinoma (BAC) in stage IA. A follow-up CT a year following the surgery revealed localized GGO in area S6 of the left lung. However, it disappeared during the gravitation-dependent gradient in the observation period. The patient was scanned again under prone position to exclude the gravitational effect, resulting in definite detection of the GGO. Left extended S6 segmentectomy with VATS was performed, and pathological diagnosis was a BAC in stage IA. As GGO existing in a gravitation-dependent area may be masked by the gravitation-dependent density, a change of the scanning position may lead to a proper detection of the tumor for the diagnosis of BAC.  相似文献   
55.
Pyopneumopericardium caused by transdiaphragmatic perforation of gastric ulcer is very rare. A 60-year-old man was admitted to our hospital because of chest pain with high fever. The chest computed tomography (CT) revealed hydropneumopericardium. The patient was diagnosed as purulent pericarditis. So emergent pericardiectomy and pericardial drainage were performed to relieve cardiac tamponade. Two findings enabled us to diagnose the causation of pyopneumopericardium as gastropericardial fistura. The first finding was that endoscopic examination of upper gastrointestinal tract revealed a deep peptic ulcer in the dome of gastric fundus. The second finding was that a dye solution which was injected into the pericardial cavity via the drainage tube leaked out into the gastric cavity through the ulcer. This patient improved successfully by the treatment of intravenous hyperalimentation including antibiotics and omeprazole. We think that expedient diagnosis and surgical drainage are essential for successful patient outcome.  相似文献   
56.
We investigated whether perioperative extensive epidural block (C3-L) affects postoperative immune response in patients undergoing radical esophagectomy. Patients undergoing radical esophagectomy were randomly assigned to either general anesthesia with continuous epidural infusion via 2 epidural catheters that was continued for postoperative analgesia (group E, n = 15) or intraoperative general anesthesia and postoperative IV morphine analgesia (group G, n = 15). Plasma levels of stress hormones, cytokines, C-reactive protein (CRP), leukocyte counts, and distribution of lymphocyte subsets were assessed before and after surgery and on postoperative days (PODs) 1 and 3. In comparison with group E, significant increases in plasma epinephrine level at the end of surgery (P < 0.05) and norepinephrine level at the end of surgery (P < 0.01) and on POD1 (P < 0.01) and POD3 (P < 0.01) and significant decrease in cluster of differentiation (CD4/CD8 ratio) at the end of surgery (P < 0.05) were observed in group G. However, there were no significant differences in other variables between groups. In both groups, plasma cortisol, adrenocorticotropic hormone, interleukin (IL)-1beta, IL-6, IL-10, and CRP levels were increased after surgery (each group P < 0.01) and IL-1beta, IL-6, IL-10, and CRP were still increased on POD1 and POD3 (each change, each group P < 0.01). Leukocyte counts were increased on POD1 (each group P < 0.05) and POD3 (each group P < 0.01). The proportion of lymphocytes decreased from the end of surgery to POD3 (each group P < 0.01). The proportion of B cells was increased on POD1 (each group P < 0.01); that of natural killer cells was decreased at POD1 and POD3 (each group P < 0.01). We conclude that tissue damage and inflammation apparently overcome the effects of extensive epidural block on stress response and immune function in radical esophagectomy.  相似文献   
57.
Nonsurgical bleeding is the most frequent complication of left ventricular assist device (LVAD) support. Supraphysiologic shear rates generated in LVAD causes impaired platelet aggregation, which increases the risk of bleeding. The effect of shear rate on the formation size of platelet aggregates has never been reported experimentally, although platelet aggregation size can be considered to be directly relevant to bleeding complications. Therefore, this study investigated the impact of shear rate and exposure time on the formation size of platelet aggregates, which is vital in predicting bleeding in patients with an LVAD. Human platelet-poor plasma (containing von Willebrand factor, vWF) and fluorochrome-labeled platelets were subjected to a range of shear rates (0-10 000 s−1) for 0, 5, 10, and 15 minutes using a custom-built blood-shearing device. Formed sizes of platelet aggregates under a range of shear-controlled environment were visualized and measured using microscopy. The loss of high molecular weight (HMW) vWF multimers was quantified using gel electrophoresis and immunoblotting. An inhibition study was also performed to investigate the reduction in platelet aggregation size and HMW vWF multimers caused by either mechanical shear or enzymatic (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13—ADAMTS13, the von Willebrand factor protease) mechanism under low and high shear conditions (360 and 10 000 s−1). We found that the average size of platelet aggregates formed under physiological shear rates of 360-3000 s−1 (200-300 μm2) was significantly larger compared to those sheared at >6000 s−1 (50-100 μm2). Furthermore, HMW vWF multimers were reduced with increased shear rates. The inhibition study revealed that the reduction in platelet aggregation size and HWM vWF multimers were mainly associated with ADAMTS13. In conclusion, the threshold of shear rate must not exceed >6000 s−1 in order to maintain the optimal size of platelet aggregates to “plug off” the injury site and stop bleeding.  相似文献   
58.
Context  Very little is known about the frequency of generation and transmissibility of influenza B viruses with reduced sensitivity to neuraminidase inhibitors. Furthermore, transmission of resistant virus, whether influenza A or B, has not been recognized to date. Objective  To assess the prevalence and transmissibility of influenza B viruses with reduced sensitivity to neuraminidase inhibitors. Design, Setting, and Patients  Investigation of the neuraminidase inhibitor sensitivity of influenza B isolates from 74 children before and after oseltamivir therapy and from 348 untreated patients with influenza (including 66 adults) seen at 4 community hospitals in Japan during the 2004-2005 influenza season. Four hundred twenty-two viruses from untreated patients and 74 samples from patients after oseltamivir therapy were analyzed. Main Outcome Measure  Sialidase inhibition assay was used to test the drug sensitivities of influenza B viruses. The neuraminidase and hemagglutinin genes of viruses showing reduced sensitivity to neuraminidase inhibitors were sequenced to identify mutations that have the potential to confer reduced sensitivity to these drugs. Results  In 1 (1.4%) of the 74 children who had received oseltamivir, we identified a variant with reduced drug sensitivity possessing a Gly402Ser neuraminidase substitution. We also identified variants with reduced sensitivity carrying an Asp198Asn, Ile222Thr, or Ser250Gly mutation in 7 (1.7%) of the 422 viruses from untreated patients. Review of the clinical and viral genetic information available on these 7 patients indicated that 4 were likely infected in a community setting, while the remaining 3 were probably infected through contact with siblings shedding the mutant viruses. Conclusions  In this population, influenza B viruses with reduced sensitivity to neuraminidase inhibitors do not arise as frequently as resistant influenza A viruses. However, they appear to be transmitted within communities and families, requiring continued close monitoring.   相似文献   
59.
Pyoderma gangrenosum is an ulcerative skin disorder showing characteristic non‐infectious ulcers and affects the lower extremities in approximately 70% of cases. Pyoderma gangrenosum is commonly associated with systemic diseases such as inflammatory bowel disease, rheumatoid arthritis and hematological malignancies. Herein, we report two cases of Japanese patients diagnosed with genital pyoderma gangrenosum. Case 1 was a 74‐year‐old woman without associated systemic complications, whose skin lesion resembled a squamous cell carcinoma and was limited to the vulva. Case 2 is an 89‐year‐old man, who suffered from myelodysplastic syndrome and acute myeloid leukemia, and presented with penile and leg ulcers mimicking pressure sores. Both cases responded well to systemic steroids. We review 13 genital pyoderma gangrenosum cases (76.9% male; aged 30–89 years) from 1996 to 2012 in Japan, including 11 previously reported cases and the present study's two cases. Four of the 13 genital pyoderma gangrenosum cases had associated systemic diseases and their skin lesions spread to the extragenital areas. Eight of the remaining nine genitalia‐localized pyoderma gangrenosum cases had no associated systemic diseases. In conclusion, genital pyoderma gangrenosum is rare and may be misdiagnosed. It should therefore be considered in cases of refractory genital ulcers. In addition, genitalia‐localized pyoderma gangrenosum tends to be without systemic complications.  相似文献   
60.
PURPOSE: Uncontrolled fibrosis due to excessive accumulation of extracellular matrix proteins in the lacrimal glands of patients with chronic graft-versus-host disease (cGVHD) is well documented. Heat-shock protein 47 (HSP47) is involved in the molecular maturation of collagen and has been shown to have a fibrogenic role in various fibrotic diseases. In this study, the role of HSP47 in the pathogenesis of lacrimal gland of patients with cGVHD was investigated. METHODS: The expression of HSP47, Ki67 (a proliferation marker), types I and III collagen, and alpha-smooth muscle actin (alpha-SMA) was examined in tissue sections and in primary cultures of fibroblasts obtained from the lacrimal glands of patients with cGVHD (n = 8) and Sj?gren's syndrome (SS; n = 7). RESULTS: Tissue sections of the lacrimal glands of patients with cGVHD showed markedly increased expression of HSP47 in fibroblasts around the medium-sized ducts than did those from patients with SS. The elevated expression of HSP47 in patients with cGVHD was mostly detected in Ki67-positive fibroblasts and was associated with increased accumulation of types I and III collagen in and around the fibrotic areas. Primary fibroblast cultures generated from cGVHD lacrimal gland showed higher HSP47 mRNA expression than did fibroblasts isolated from SS biopsy tissue, as determined by RT-PCR (P < 0.05). In contrast, alpha-SMA was higher in the SS than cGVHD fibroblasts at both mRNA and protein levels, and more lacrimal gland fibroblasts in the SS were positive for alpha-SMA than cGVHD (P < 0.01). CONCLUSIONS: In cGVHD, increased expression of HSP47 may promote excessive collagen assembly in and around the periductal areas where fibroblasts are mostly in an active state. The less alpha-SMA in the cGVHD lacrimal gland fibroblasts suggests a relative lack of myofibroblastic transformation. It is likely that fibroblasts incapable of myofibroblastic transformation are the main source of HSP47 and collagen production, and the resultant effect is the periductal fibrotic changes seen in lacrimal glands of patients with cGVHD.  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