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   1415篇
  免费   45篇
  国内免费   75篇
耳鼻咽喉   4篇
儿科学   57篇
妇产科学   15篇
基础医学   117篇
口腔科学   27篇
临床医学   156篇
内科学   318篇
皮肤病学   36篇
神经病学   54篇
特种医学   301篇
外科学   146篇
综合类   39篇
预防医学   84篇
眼科学   28篇
药学   66篇
中国医学   6篇
肿瘤学   81篇
  2023年   7篇
  2021年   15篇
  2020年   12篇
  2019年   20篇
  2018年   18篇
  2017年   12篇
  2016年   14篇
  2015年   21篇
  2014年   19篇
  2013年   28篇
  2012年   47篇
  2011年   36篇
  2010年   46篇
  2009年   62篇
  2008年   33篇
  2007年   64篇
  2006年   43篇
  2005年   50篇
  2004年   34篇
  2003年   24篇
  2002年   32篇
  2001年   27篇
  2000年   34篇
  1999年   28篇
  1998年   87篇
  1997年   75篇
  1996年   61篇
  1995年   53篇
  1994年   46篇
  1993年   45篇
  1992年   31篇
  1991年   19篇
  1990年   31篇
  1989年   43篇
  1988年   36篇
  1987年   31篇
  1986年   28篇
  1985年   25篇
  1984年   23篇
  1983年   13篇
  1982年   21篇
  1981年   10篇
  1980年   14篇
  1979年   7篇
  1978年   9篇
  1977年   16篇
  1976年   13篇
  1975年   15篇
  1970年   8篇
  1871年   10篇
排序方式: 共有1535条查询结果,搜索用时 15 毫秒
101.
PURPOSE: To assess the efficacy of treating pleural effusions in lung transplant recipients with small-bore catheter drainage. MATERIALS AND METHODS: Chest radiographs and computed tomographic (CT) scans obtained in 31 lung transplant recipients who had pleural effusions treated with catheter drainage were retrospectively reviewed. Duration of drainage and volume of fluid drained were recorded. Results were evaluated 1 and 3 months after chest tube removal. There was complete response (CR) when no pleural fluid remained, partial response (PR) when fluid remaining was less than the pretreatment level, and no response (NR) when fluid recurred to a level at or above the pretreatment level. Associations between cause of effusion (empyema, parapneumonic effusion, rejection, other), response (CR, PR, NR), and type of transplantation (unilateral, bilateral) were examined by using chi2 tests. RESULTS: Of 31 patients, 25 had bilateral effusions; eight of these 25 patients had small-bore catheters inserted bilaterally. Nine patients had multiple sequential catheter insertions. Duration of drainage ranged from 2 to 44 days (median, 6 days). Fluid output was 110-9,726 mL (median, 1,350 mL). One-month follow-up data were available for 31 of 39 treated pleural effusions: 11 (35%) had CR, 18 (58%) had PR, and two (6%) had NR (percentages do not add up to 100% due to rounding). Three-month follow-up data were available for 28 of 39 treated effusions: 22 (79%) had CR, five (18%) had PR, and one (4%) had NR (percentages do not add up to 100% due to rounding). One- and 3-month response rates, respectively, were not related to cause of effusion (P =.82 and.535) or type of transplantation (P =.568 and >.999). CONCLUSION: Small-bore catheter drainage of persistent pleural effusions in lung transplant recipients is usually successful, but drainage is often prolonged and may require multiple catheter placements.  相似文献   
102.
103.
甲硝唑葡萄糖注射液细菌内毒素检查法的研究   总被引:1,自引:0,他引:1  
目的;以细菌内毒素检查法对甲硝唑葡萄糖注射液进行试验研究。方法;采用抑制或增强试验,并将细菌内毒素检查法与家兔法检测结果作对比。结果:该注射液经一定稀释后对测定无干扰。结论:细菌内毒素检查法适用于检测该注射液。  相似文献   
104.
Patz EF  Erasmus JJ 《Clinical lung cancer》1999,1(1):42-8; discussion 49
Over the past several years, positron emission tomography (PET) has become a clinically useful, noninvasive study which complements conventional imaging (chest radiographs, computed tomography [CT], and magnetic resonance imaging [MRI]) in the evaluation of patients with lung cancer. PET imaging of lung cancer is typically performed with the radiopharmaceutical 18F-2-deoxy-D-glucose (FDG), a d-glucose analog. Increased glucose metabolism by malignant cells results in increased uptake and accumulation of FDG, which serves as the basis for tumor detection. This review will focus on the current applications of FDG-PET in lung cancer patients including evaluation of focal pulmonary abnormalities, staging lung cancer, determining tumor recurrence, and in assessing prognosis.  相似文献   
105.
106.
SUMMARY A young patient presenting with splenomegaly and hypersplenism was inadvertently found to have selective IgA deficiency. There were no symptoms of immunodeficiency and the patient responded well to splenectomy, with return of blood counts to normal without adverse effects. No other cause for the hypersplenism was found. We postulate selective IgA deficiency as a cause of splenomegaly and hypersplenism.  相似文献   
107.
恶性肿瘤淋巴管生成与转移的研究进展   总被引:1,自引:0,他引:1  
张海娥  庄建基  杨帆 《医学争鸣》2007,28(5):479-480
淋巴道转移是肿瘤转移的重要途径,也是判断预后的重要依据. 随着淋巴管生成因子及许多淋巴管特异性标记物的发现,肿瘤新生淋巴管调控与淋巴道转移机制研究得以深入开展. 大量的研究发现,恶性肿瘤和瘤周组织内存在新生的淋巴管,新生的淋巴管密度和淋巴管标记物的表达强度均与淋巴结转移密切相关. 这为揭示恶性肿瘤淋巴道转移机制和开发淋巴管靶向治疗提供了重要的研究途径. 现就近年来肿瘤淋巴管生成与转移的研究进展作一综述.  相似文献   
108.

Background.

EGFR and Src are frequently activated in non-small cell lung cancer (NSCLC). In preclinical models, combining EGFR and Src inhibition has additive synergistic effects. We conducted a phase I/II trial of the combination of Src inhibitor dasatinib with EGFR inhibitor erlotinib to determine the maximum tolerated dose (MTD), pharmacokinetic drug interactions, biomarkers, and efficacy in NSCLC.

Methods.

The phase I 3+3 dose-escalation study enrolled patients with solid tumors to determine the MTD. The phase II trial enrolled patients with advanced NSCLC who had undergone no previous treatments to determine progression-free survival (PFS) and response. Pharmacokinetic and tissue biomarker analyses were performed.

Results.

MTD was 150 mg of erlotinib and 70 mg of dasatinib daily based on 12 patients treated in the phase I portion. No responses were observed in phase I. The 35 NSCLC patients treated in phase II had an overall disease control rate of 59% at 6 weeks. Five patients (15%) had partial responses; all had activating EGFR mutations. Median PFS was 3.3 months. Epithelial-mesenchymal transition markers did not correlate with outcomes.

Conclusion.

The combination of erlotinib and dasatinib is safe and feasible in NSCLC. The results of this study do not support use of this combination in molecularly unselected NSCLC.  相似文献   
109.
The feasibility of using magnetic resonance (MR) imaging to estimate myocardial infarct size was explored in an in vitro model using only the inherent differences in contrast between infarcted and noninfarcted myocardium. Eight dogs underwent coronary occlusion; their hearts were removed 6 hours later. Estimates of T2 for normal and infarcted myocardium were derived from MR images. Infarct size was quantified anatomically using triphenyltetrazolium-chloride (TTC) staining and compared with MR estimates. The T2 values derived from the images clearly discriminated between infarcted (126 +/- 22 msec) and normal myocardium (88 +/- 10 msec, P less than .05), providing images with good contrast between normal and infarcted myocardium. Comparable differences in T2 values were also noted from spectrometric determinations. Estimates of infarct size by MR imaging compared well with TTC estimates (r = 0.98) over a wide range of infarct sizes from 3% to 29% of the left ventricular mass. These results suggest the potential for in vivo quantification of infarct size based on the inherent contrast difference between infarcted and normal myocardium.  相似文献   
110.
Sanfilippo B syndrome is caused by a deficiency of alpha-N- acetylglucosaminidase, a lysosomal enzyme involved in the degradation of heparan sulphate. Accumulation of the substrate in lysosomes results in degeneration of the central nervous system with progressive dementia often combined with hyperactivity and aggressive behaviour. In order to clone the deficient gene, we purified the enzyme from human placenta and obtained amino acid sequence information. Alignment of one of the CNBr generated internal peptides to sequence from the database revealed the chromosomal location of the gene in the 5' upstream flanking region of the gene for 17-beta-hydroxysteroid-dehydrogenase at 17q21.1. The available DNA sequence was used to clone the cDNA coding for alpha-N- acetylglucosaminidase and analyse its gene structure. The gene is fully contained in the 5' upstream flanking region of the gene for 17-beta- hydroxysteroid-dehydrogenase and interrupted by five introns. The cDNA clone has a length of 2575 bp and encodes a protein of 743 amino acids. Chinese hamster ovary cells transfected with the cDNA construct show alpha-N-acetylglucosaminidase activity about 17-fold over background. This will allow correction studies with NAG deficient Sanfilippo B cell lines and facilitate the development of enzyme replacement therapy for these patients.   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