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   2934篇
  免费   155篇
  国内免费   16篇
耳鼻咽喉   6篇
儿科学   139篇
妇产科学   55篇
基础医学   318篇
口腔科学   37篇
临床医学   139篇
内科学   725篇
皮肤病学   24篇
神经病学   139篇
特种医学   167篇
外科学   618篇
综合类   15篇
预防医学   63篇
眼科学   156篇
药学   175篇
中国医学   3篇
肿瘤学   326篇
  2023年   24篇
  2022年   65篇
  2021年   94篇
  2020年   38篇
  2019年   72篇
  2018年   80篇
  2017年   65篇
  2016年   67篇
  2015年   99篇
  2014年   124篇
  2013年   130篇
  2012年   207篇
  2011年   244篇
  2010年   128篇
  2009年   120篇
  2008年   173篇
  2007年   226篇
  2006年   176篇
  2005年   179篇
  2004年   185篇
  2003年   162篇
  2002年   144篇
  2001年   27篇
  2000年   31篇
  1999年   30篇
  1998年   30篇
  1997年   16篇
  1996年   20篇
  1995年   25篇
  1994年   18篇
  1993年   17篇
  1992年   20篇
  1991年   9篇
  1990年   4篇
  1989年   11篇
  1988年   6篇
  1987年   6篇
  1986年   3篇
  1985年   2篇
  1983年   3篇
  1982年   3篇
  1981年   4篇
  1979年   2篇
  1978年   2篇
  1977年   2篇
  1974年   1篇
  1971年   4篇
  1969年   1篇
  1964年   1篇
  1963年   1篇
排序方式: 共有3105条查询结果,搜索用时 15 毫秒
41.
We investigated the role of donor bone marrow cell (DBMC) infusions in immunosuppression withdrawal in adult liver transplantation. Patients enrolled were at least 3 years post-transplantation, with stable graft function. Forty-five (study group: G1) received DBMC, and 59 (control group: G2) did not. Immunosuppression was reduced by one third upon enrollment, by another third the second year of the study and was completely withdrawn the third year. Patient and graft survival were similar between the two groups. Although rejection episodes were significantly less in G1 the first 2 years of the study (35% vs. 57%, p = 0.016), there was no significant difference overall (74% vs. 81%, p = 0.14). Until February 2004, 20 patients, 10 in each group, were immunosuppression free for 1-3 years. Approximately 20% of long-term survivors of liver transplantation can successfully discontinue their immunosuppression. DBMC infusions, do not increase this likelihood.  相似文献   
42.
OBJECTIVE: Pulmonary metastasis of non-small cell lung cancer is classified as an advanced disease stage, with limited indications for surgical treatment. However, the prognosis of patients with pulmonary metastasis of non-small cell lung cancer is better than that of patients with distant metastases. The purpose of the present study was to analyze and detect possible prognostic factors in surgically treated patients with ipsilateral pulmonary metastasis of non-small cell lung cancer. METHODS: Among 1198 patients with non-small cell lung cancer who underwent surgery at Kurashiki Central Hospital (Okayama, Japan) from April 1982 to March 2004, a total of 48 (4.0%) patients with pathologically diagnosed ipsilateral pulmonary metastasis were retrospectively evaluated. The median follow-up time was 20.5 months (range 1-103 months) and 37 patients (77.1%) were completely followed up until their death or more than 5 years after the operation. RESULTS: Among the 48 patients, 31 (64.6%) patients had metastatic nodules in the same lobe as the primary tumor (PM1) and 17 (35.4%) patients had metastatic nodules in different ipsilateral lobes (PM2). There was no significant difference in survival between patients with PM1 and the other patients with pT4-stage IIIB, or between patients with ipsilateral PM2 and the other patients with stage IV. Univariate analysis of postoperative survival stratified according to clinicopathologic factors revealed significant differences for the radicality of resection (complete vs. incomplete), tumor size (0-30 vs. >30mm) and pathological nodal (pN) factor (among pN0, pN1 and pN2-3). Multivariate analysis revealed that tumor size (0-30 vs. >30mm) and pN factor (pN0-1 vs. pN2-3) were independent prognostic factors. CONCLUSIONS: The results of our study suggest that undergoing a complete resection, having a tumor size of 30mm or less and having no mediastinal lymph node metastases were better prognostic factors for surgically treated patients with ipsilateral pulmonary metastasis of non-small cell lung cancer.  相似文献   
43.
A 20-year-old man presented with diplopia. Neurological examination revealed mild skew deviation and upbeat nystagmus. Computed tomography showed a clover-shaped isodense mass in the pineal region with homogeneous enhancement. The lesion was isointense on both T(1)- and T(2)-weighted magnetic resonance (MR) imaging with homogeneous enhancement by gadolinium-diethylenetriaminepenta-acetic acid. Cerebral angiography showed no tumor staining. Serum and cerebrospinal fluid were negative for beta-human chorionic gonadotropin, alpha-fetoprotein, and placental alkaline phosphatase. Open biopsy was performed using a right occipital transtentorial approach. Histological examination revealed a tumor consisting of clusters of germinoma cells, but with prominent infiltration of lymphocytes, plasma cells, and macrophages, and proliferation of small vessels. The histological diagnosis was germinoma with granulomatous reaction. MR imaging showed complete disappearance of the tumor after chemoradiotherapy. Neurosurgeons should be aware of this rare tumor to avoid misdiagnosis as granulomatous inflammation.  相似文献   
44.
45.
PURPOSE: To evaluate the integrity of photoreceptors in macular edema (ME) associated with branch retinal vein occlusion after intravitreal tissue plasminogen activator. DESIGN: Retrospective, interventional case series. METHODS: Nineteen eyes with ME by branch retinal vein occlusion were treated with intravitreal tissue plasminogen activator injection. We assessed visual acuity (VA) and the presence or absence in the fovea of a third high reflectance band (HRB) by optical coherence tomography at the final visit. RESULTS: No differences were found in age, preoperative VA, and foveal thickness between the groups with or without the third HRB. After treatment, the mean VA improved significantly (P < .05) in both groups. At the final visit, the mean VA in the group without HRB was significantly poorer than the group with HRB (P = .0042); foveal thickness did not differ between the groups. CONCLUSIONS: The integrity of the third HRB in the fovea is associated with VA after the resolution of ME.  相似文献   
46.
PURPOSE: To diagnose an atypical retinal degenerative disease with choroidal neovascularization by means of gene diagnosis. CASE: A 47-year-old woman had good visual acuity at the first examination. She had scattered chorioretinal degeneration and pigmentation in the peripheral retina. There was a symmetrical visual field defect in the upper and temporal periphery in both eyes. Seven years later, choroidal neovascular membrane (CNV) developed in the fovea of her left eye and visual acuity deteriorated to 0.4 in this eye. Optical coherence tomography revealed type 2 CNV with minimal subretinal fluid. Fluorescein angiography showed very little leakage from the CNV. We used denaturing high performance liquid chromatography(DHPLC) to perform gene diagnosis and found a peripherin/RDS gene mutation of Gly167-Ser. CONCLUSION: Our case had moderate peripheral retinal degeneration with CNV. It is possible that cases like this tend to be misdiagnosed as AMD (age-related macular degeneration) or CNV with high myopia. Evaluation of the gene mutation was useful for diagnosis in this case.  相似文献   
47.
BACKGROUND/AIMS: Bile acids are synthesized in the liver and released into the intestinal tract to aid in digestion and absorption by increasing permeability via alteration of the cell membrane. Bedridden elderly patients typically have pressure ulcers that may be due to both physical local pressure as well as skin cell changes induced by the physiologic effects of bile acids. METHODOLOGY: This study investigated 31 elderly bedridden patients with pressure ulcers (mean age, 81.7 years) and 19 healthy elderly (mean age, 79.7 years). Five serum bile acid fractions were summed to determine total bile acid, and transaminase and cholesterol levels were also measured. RESULTS: Total cholesterol levels were significantly lower (p<0.05) in pressure ulcer patients and transaminase levels were not significantly different between the two groups. The primary bile acids were generally higher and the secondary and tertiary bile acids lower in pressure ulcer patients. In particular, the secondary bile acid deoxycholic acid was significantly higher in all pressure ulcer patients. When analyzed by grade of pressure ulcer, the primary bile acids were significantly lower in pressure ulcer patients. CONCLUSIONS: Secondary bile acid fraction deoxycholic acid measurements may indicate bedridden patients at higher risk for pressure ulcers.  相似文献   
48.
BACKGROUND: The clinical significance of the white blood cell (WBC) count on admission in relation to the duration of ischemia in acute myocardial infarction (AMI) remains unclear. METHODS AND RESULTS: The relationship of the WBC count on admission to myocardial reperfusion was examined in 135 patients with recanalization of an anterior AMI within 6 h of symptom onset. Patients were classified according to the WBC count on admission: Group L (n=75), WBC count <12,000 cells/mm(3) and group H (n=60), WBC count >or=12,000 cells/mm(3). Peak creatine kinase (CK) was higher and impaired myocardial reperfusion, defined as a myocardial blush grade of 0/1, was more frequent in group H than in group L. Among the patients in group H, those with early (3 h) recanalization; however, peak CK and the incidence of impaired myocardial reperfusion were similar in these subgroups of patients. Multivariate analysis showed that WBC count >or=12,000 cells/mm(3) on admission was an independent predictor of impaired myocardial reperfusion in patients with early recanalization (odds ratio 7.9, p=0.04), but not in those with late recanalization. CONCLUSIONS: A higher WBC count may be associated with progression of myocardial damage after recanalization in patients with early recanalization of an anterior AMI.  相似文献   
49.
50.
Journal of Thrombosis and Thrombolysis - Pulmonary thromboembolism (PTE) is one of the leading causes of maternal mortality. We previously reported that possible contamination of amniotic fluid...  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