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   10076篇
  免费   499篇
  国内免费   56篇
耳鼻咽喉   139篇
儿科学   181篇
妇产科学   195篇
基础医学   1539篇
口腔科学   205篇
临床医学   602篇
内科学   2291篇
皮肤病学   268篇
神经病学   572篇
特种医学   384篇
外科学   1779篇
综合类   26篇
预防医学   367篇
眼科学   149篇
药学   728篇
中国医学   16篇
肿瘤学   1190篇
  2023年   50篇
  2022年   85篇
  2021年   144篇
  2020年   83篇
  2019年   121篇
  2018年   133篇
  2017年   119篇
  2016年   161篇
  2015年   163篇
  2014年   205篇
  2013年   259篇
  2012年   450篇
  2011年   456篇
  2010年   259篇
  2009年   245篇
  2008年   455篇
  2007年   498篇
  2006年   500篇
  2005年   491篇
  2004年   475篇
  2003年   488篇
  2002年   498篇
  2001年   381篇
  2000年   403篇
  1999年   361篇
  1998年   169篇
  1997年   126篇
  1996年   98篇
  1995年   91篇
  1994年   67篇
  1993年   68篇
  1992年   222篇
  1991年   177篇
  1990年   204篇
  1989年   214篇
  1988年   215篇
  1987年   180篇
  1986年   169篇
  1985年   147篇
  1984年   117篇
  1983年   99篇
  1982年   44篇
  1979年   65篇
  1978年   45篇
  1977年   52篇
  1975年   44篇
  1974年   45篇
  1973年   52篇
  1972年   51篇
  1970年   48篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Type III GM1-gangliosidosis is a rare hereditary storage disease caused by lack of lysosomal beta-galactosidase and characterized by a slowly progressive course, and extrapyramidal signs, but without prominent skeletal changes or visceromegaly. The storage substance was reported to be located only in the basal ganglia. There has been no detailed report on visceral lesions in type III GM1-gangliosidosis. In this report we describe a case of type III GM1-gangliosidosis, and the histochemical and ultrastructural findings from biopsied rectum. The patient was a 22-year-old female who exhibited dysarthria, gait disturbance, and generalized dystonia with rigidity. Beta-galactosidase activity in leukocytes was absent and sialidase activity in cultured fibroblasts was normal. Many histiocytes were found in biopsied rectal mucosa. Histochemical studies showed that the granules of histiocytes contained acidic glycoconjugates, beta-galactose, beta-N-acetylgalactosamine and sialic acid. Ultrastructural investigations revealed that ganglion cells of Meissner's plexus had many osmiophilic lamellar inclusions, similar to "membranous cytoplasmic bodies". These findings are crucial for the clinical diagnosis of type III GM1-gangliosidosis.  相似文献   
102.
Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease. Although several cases of BP in end-stage renal disease patients receiving peritoneal dialysis (PD) or hemodialysis have been reported, the incidence of BP in these patients remains unknown. We recently experienced three PD patients diagnosed with BP. The skin injury was likely to be a trigger of BP in all the three PD patients. Nifedipine and icodextrin exposures were possible factors directly or indirectly affecting the onset of BP, because they were common in the three cases. We also report that the incidence of BP in PD patients was 3/478.3 person-years in a single-center 10-year study. This case series with a literature survey describes that the skin and tissue injuries are potential triggers responsible for the onset of BP in dialysis patients and that the incidence of BP in these patients seems to be much higher than that in the general population.  相似文献   
103.
PurposeTissue engineering of esophagus is required for management of long-gap esophageal atresia (LGEA). Collagenous connective tissue membranes fabricated by in-body tissue architecture (iBTA), called biosheets, can repair esophageal defects and generate tissues similar to native esophagus. However, iBTA requires second-stage surgery because of heterotopic preparation of biosheets. Our aim was to develop orthotopic iBTA for primary engineering of the esophagus by interposing a tubular mold to the esophageal defect.MethodThe cervical esophagus of six rats was transected. An acrylic tube (internal diameter 2.6 mm, length 7.0 mm) was inserted and fixed between the ends of the upper and lower esophagus, and a 3 mm-long esophageal defect was created. Four weeks later, the rats were sacrificed for histological analysis.ResultsPostoperatively the rats could intake liquid food. After four weeks, the esophageal defects were filled with regenerated tissues. Histologically the new esophageal walls stained positive for collagen type I. The inner surfaces were covered with stratified squamous epithelium that expressed pan-cytokeratin. In only one of six rats, regeneration of muscular-like tissue was suggested by positive immunohistochemical staining for desmin.ConclusionOrthotopic iBTA can regenerate a substitute esophagus with esophageal epithelium and collagenous wall. This technique may be a novel treatment for esophageal atresia with gaps of various lengths including LGEA.  相似文献   
104.
Jan Hendrik Louw (1915–1992), considered the father of pediatric surgery in South Africa, gained prominence for his work on congenital intestinal atresia, a condition that had a mortality as high as 75 percent. His hypothesis, that jejunoileal atresia arose from mesenteric circulatory accidents in utero, was the dominant view until recent research uncovered the involvement of genetic and embryological mechanisms. In the mid-1950s he was one of a number of surgeons to resect the enlarged bulbous segment proximal to the site of the atresia, a crucial step in the surgical approach to intestinal atresia that brought mortality below 10 percent. A world leader in surgery as chair of surgery at the Groote Schur Hospital in Cape Town for more than a quarter century, his work in surgical research took root from his private tragedy early in his career of the death of his own infant son of intestinal atresia, a condition to which he would contribute so much.  相似文献   
105.
The ACOSOG Z0011 trial has resulted in the omission of axillary lymph node dissection (ALND) in early breast cancer patients with one or two metastatic sentinel lymph nodes (SLNs). There has been increasing interest in the necessity of intraoperative assessment of SLNs in patients treated based on the Z0011 criteria. We evaluated the utility of intraoperative assessment in these eligible patients. A total of 1396 patients were treated following the Z0011 criteria from April 2012 to December 2019. We examined the proportion and clinicopathological features of patients who underwent ALND due to three or more metastatic SLNs and the sensitivity of intraoperative assessment. Only 16 (1.1%) patients had three or more metastatic SLNs diagnosed by intraoperative assessment, and they immediately underwent ALND. Of the clinicopathological factors, high clinical tumor stage (p = 0.002) and high Ki-67 labeling index value (p = 0.056) were more likely to be associated with the presence of three or more metastatic SLNs. The major independent risk factor for three or more metastatic SLNs was high clinical tumor stage (OR 3.94 [95% CI 1.42–11.0]; p = 0.009). Intraoperative assessment had low sensitivity (70.5%) and a high false-negative rate (29.5%) in detecting SLN metastases. The main finding of our study was the small proportion of patients who required ALND due to three or more metastatic SLNs according to the Z0011 criteria. The Z0011 strategy enables intraoperative assessment of SLNs to be omitted in early breast cancer patients.  相似文献   
106.
Although systemic therapy is the standard treatment for metastatic prostate cancer, a randomized controlled trial showed radiotherapy to the prostate improved overall survival of metastatic prostate cancer patients with the low metastatic burden. Additionally, a randomized phase II trial showed that metastasis-directed therapy for oligo-recurrent prostate cancer improved androgen-deprivation therapy (ADT)-free survival. Therefore, administering radiotherapy to both prostate and metastatic regions might result in better outcomes. Thus, we report the treatment results of radiotherapy to both prostate and metastatic regions. Our institutional database was searched for patients who received radiotherapy to the prostate and metastatic regions. We summarized patient characteristics and treatment efficacy and performed statistical analysis to find possible prognostic factors. A total of 35 patients were included in this study. The median age was 66 years, and the median initial prostate-specific antigen (PSA) level was 32 ng/ml. The Gleason score was 7 in 10 patients, 8 in 13 patients, and 9 in 12 patients. The median radiotherapy dose was 72 Gy to the prostate and 50 Gy to the metastatic bone region. The 8-year overall survival, cause-specific survival, progression-free survival, and freedom from biochemical failure rate were 81, 85, 53, and 57%. Among the 35 patients, 12 were disease-free even after ADT was discontinued. In selected patients with metastatic prostate cancer, ADT and radiotherapy to the prostate and metastatic sites were effective. Patients with good response to ADT may benefit from radiotherapy to both prostate and metastatic regions.  相似文献   
107.
Myelodysplastic syndrome and acute myelofibrosis   总被引:1,自引:0,他引:1  
  相似文献   
108.
Real world occlusion constraints and binocular rivalry   总被引:5,自引:1,他引:4  
A surface occluding a more distant surface gives rise to interocularly unpaired regions to its immediate left and right. The unpaired region on the left side is visible only to the left eye, whereas that on the right side is visible only to the right eye. Thus for real world scenes there are opto-geometrical constraints which determine whether particular combinations of relative depth and right-eye-only or left-eye-only stimuli are ecologically valid or invalid. We report a demonstration and experiments to show that opto-geometrically "valid" unpaired regions are seen as continuous with the rear plane and escape interocular suppression, whereas "invalid" unpaired regions are perceived as closer and are suppressed vigorously. An additional experiment indicates that the results cannot be understood in terms of correspondence solving, but require neural mechanisms that embody real-world occlusion constraints. These results suggest a rather close interaction between stereopsis and rivalry "modules". Since explicit eye-of-origin information is lost relatively early in the hierarchical organization of cortical visual processing, we argue that occlusion-related constraints must be embodied at such early levels.  相似文献   
109.
A 55-year-old male patient with acute onset of abdominal pain was examined. He had no apparent history of abdominal trauma or bleeding tendency. MRI showed three layered architecture, so-called "ring sign" distinctive of hematoma. MRI seemed to be very useful in non-invasively diagnosing intramural duodenal hematoma.  相似文献   
110.
CA19-9 and CEA are associated with gastrointestinal malignancy as adhesion molecules. We measured serum CA19-9 and CEA levels in 328 patients with colorectal cancer. Both serum CA19-9 and CEA levels correlated significantly with recurrence and survival, respectively. Serum CA19-9 levels correlated significantly with survival according to Astler-Coller stage and multivariate analysis. Serum CEA levels showed no such correlations, although the combination of CEA with CA19-9 improved the sensitivity for predicting recurrence. Assessment of serum CA19-9 levels is more important than that of CEA in the clinical management of patients with colorectal cancer.  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