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   1163篇
  免费   61篇
  国内免费   13篇
耳鼻咽喉   10篇
儿科学   43篇
妇产科学   38篇
基础医学   166篇
口腔科学   12篇
临床医学   86篇
内科学   232篇
皮肤病学   77篇
神经病学   135篇
特种医学   54篇
外科学   101篇
综合类   11篇
一般理论   5篇
预防医学   75篇
眼科学   15篇
药学   109篇
中国医学   2篇
肿瘤学   66篇
  2023年   9篇
  2022年   11篇
  2021年   20篇
  2020年   13篇
  2019年   13篇
  2018年   24篇
  2017年   19篇
  2016年   27篇
  2015年   31篇
  2014年   43篇
  2013年   63篇
  2012年   66篇
  2011年   72篇
  2010年   53篇
  2009年   39篇
  2008年   71篇
  2007年   64篇
  2006年   80篇
  2005年   84篇
  2004年   58篇
  2003年   53篇
  2002年   55篇
  2001年   15篇
  2000年   19篇
  1999年   26篇
  1998年   18篇
  1997年   6篇
  1996年   6篇
  1995年   5篇
  1994年   9篇
  1993年   6篇
  1992年   9篇
  1991年   15篇
  1990年   15篇
  1989年   15篇
  1988年   12篇
  1987年   5篇
  1985年   10篇
  1984年   5篇
  1983年   5篇
  1981年   3篇
  1979年   8篇
  1977年   7篇
  1976年   5篇
  1975年   5篇
  1974年   3篇
  1973年   4篇
  1972年   3篇
  1971年   3篇
  1965年   4篇
排序方式: 共有1237条查询结果,搜索用时 15 毫秒
961.
Adrenomedullin regulates blood-brain barrier functions in vitro.   总被引:8,自引:0,他引:8  
Adrenomedullin (AM) is an important vasodilator in cerebral circulation, and cerebral endothelial cells are a major source of AM. This in vitro study aimed to determine the AM-induced changes in blood-brain barrier (BBB) functions. AM administration increased, whereas AM antisense oligonucleotide treatment decreased transendothelial electrical resistance. AM incubation decreased BBB permeability for sodium fluorescein (mol. wt 376 Da) but not for Evan's blue albumin (mol. wt 67 kDa), and it also attenuated fluid-phase endocytosis. AM treatment resulted in functional activation of P-glycoprotein efflux pump in vitro. Our results indicate that AM as an autocrine mediator plays an important role in the regulation of BBB properties of the cerebral endothelial cells.  相似文献   
962.
OBJECTIVES: This is a retrospective study to evaluate the efficacy and accuracy of the multiplex polymerase chain reaction (PCR) amplification, for early detection of fetuses at risk for hemolytic disease, in the population living in Portugal, and to characterize the RhD-negative individuals at serologic and molecular level. METHODS: 2030 uncultured amniotic fluid samples and 2012 blood samples from the respective RhD-negative pregnant women were studied by multiplex PCR of intron 3/intron 4, exon 7 and 3'UTR. Amniocentesis was performed for a variety of medical indications. For quality control, serologic RhD blood groups were determined in the cord blood, after birth. RESULTS: 1361 fetal amniotic samples were RhD-positive (67%), 669 were RhD-negative. The average time for diagnosis was 2 days for uncultured amniocytes and the molecular versus serologic RhD typing (n = 809) had 99.5% concordance. Among the 2012 serologic RhD-negative mothers, 26 had an RhD-positive allele. CONCLUSION: The multiplex PCR amplification used in this study was a rapid and accurate method to determine the RhD blood type in the population living in Portugal, being a great tool for management of pregnancies with fetuses at risk for alloimmune hemolytic disease. In this population, 1.3% of the serologic RhD-negative women have an RHD-positive allele.  相似文献   
963.
The most common causes of galactosemia are mutations of the gene coding galactose-1-phosphate uridyltransferase. Since genotype may correlate with the outcome of the disease, and probably not all of the naturally occurring disease associated mutations are described, characterization of the genotypes in different galactosemic populations are in progress. So far the most extensively examined mutations are the Q188R and the N314D. The first one is associated with the classical galactosemia producing a severe clinical picture with an early onset in homozygous patients. The N314D mutation is associated with the Duarte phenotype, which means a milder form of the disease with a later onset of the symptoms. We studied these mutations in the whole Hungarian galactosemic population by PCR and restriction analysis. We have found the frequency of the Q188R mutation at 33.3%, and the N314D mutation at 11.1%. These results differ from other published data in any other populations. Since the incidence of the disease is the same in Hungary as in other European countries, our study suggests that it is worth to investigate for other mutations in the Hungarian population, of which frequency should be consequently higher.  相似文献   
964.
Z-plate instrumentation in thoracolumbar spinal fractures.   总被引:9,自引:0,他引:9  
Anterior decompression enables direct access and good canal clearance of the injury level in thoracolumbar spinal fractures, and decompressing the neural elements is shown to be an important factor for neurologic improvement and pain relief in many cases. In this study, results with anterior decompression and Z-plate instrumentation in thoracolumbar spinal fractures are reviewed. Nineteen patients with old spinal fracture (average: 3 years) and neural compression, and 15 patients with fresh thoracolumbar fractures with neurologic deficit and/or major anterior spinal canal obstruction had anterior decompression and Z-plate instrumentation with anterior fusion. Stabilization was protected with thoracolumbar thermoplastic braces for six months. Preoperative kyphotic deformity averaged 20.9 degrees (range: 7 degrees to 64 degrees), while it was an average of 8.0 degrees (range: -12 degrees to 35 degrees) postoperatively. Medullary canal compromise was 41% an average (range: 13% to 67%) and postoperatively it had an average value of 6% (range: 0% to 18%). Patients were followed up an average of 30 months (range: 25 to 36 months). The unchanged positions of bone grafts and statistically insignificant loss of correction in the sagittal plane are accepted as evidence for bony fusion in all patients. Z-plate instrumentation provides stable fixation. Additionally, the technique can be performed easily and has the added benefit of being MRI-compatible.  相似文献   
965.
966.
BACKGROUND/AIM: The use of peripheral blood as a source of hematopoietic stem cells (SCs) is progressively increasing and has nearly supplanted bone marrow transplantation. Interpatient variability in the degree and kinetics of SC mobilization into peripheral blood is an expected event after conventional chemotherapy-based treatment, followed by sequential administration of recombinant granulocyte-colony-stimulating factor (rHu-CSF). In this study, specific factors associated with the application of two different SC-harvesting approaches, including the use of large volume leukapheresis (LVL) vs. repetitive conventional apheresis (RCA), were analyzed. The basic goal of the study was to evaluate the influence of apheresis protocol (collection timing, processed blood volume and cell yield) upon the clinical outcome of transplantation. METHODS: Results obtained by LVL (76 pts) and RCA (20 pts--control group) were compared. The SC mobilizing regimen used was cyclophosphamide (4-7 g/m2) or polychemotherapy and rHuG-CSF 10-16 microg/kg of body mess (bm) per day. Cell harvesting was performed using Caridian-BCT Spectra (Gambro, USA). The volume of processed blood in LVL setting was > or = 3.5-fold of the patient's circulating blood quantity (ranged from 12.7 to 37.8 l). All patients tolerated well the use of intensive treatment, without any side or adverse effects. Our original controlled-rate cryopreservation was carried out with 10% dimethyl sulfoxide (DMSO) using Planer R203/200R or Planer 560-16 equipments (Planer Products Ltd, UK). Total nucleated cell (NC) and mononuclear cell (MNC) counts were examined by flow cytometry (Advia-2120 Bayer, Germany; Technicon H-3 System, USA). The CD34+ cell surface antigen was investigated by the EPICS XL-MCL device (Coulter, Germany). RESULTS: Performing LVL-apheresis, high-level MNC and CD34+ cell yields (7.6 +/- 4.6 x 10(8)/kg bm and 11.8 +/- 6.5 x 10(6)/kg bm, respectively) were obtained. As a result, rapid hematopoietic reconstitution ("graft-healing")--on the 9.4th and 12.4th day for granulocytes and platelets, respectively was achieved. Using repetitive conventional apheresis (2-3 procedures), the total MNC count was high (8.2 +/- 7.0 x 10(8)/kg bm), but the total CD34+ yield was lower 10.8 +/- 9.9 due to inferior CD34+ vs. MNC ratio. CONCLUSION: The results obtained suggest that well-timed LVL-apheresis increased SC-yield in cell harvest, resulting in faster bone marrow repopulation and hematological reconstitution, as well as better overall clinical outcome of transplantation. These results necessitate additional examinations of CD34+ subsets ratio in cell harvest.  相似文献   
967.
968.
Vitiligo is common acquired pigmentary disorder affecting skin of 1% of the world population, India 3% to 8% incidences approximately. Treatment is tough challenge. The combination treatments have proven beneficial due to different mechanisms. There is need to find drug targeting different mechanisms of action. Test medicine is decapeptide derived from basic Fibroblast Growth Factor (bFGF) treating vitiligo. The current study was to compare efficacy and safety of BFGF related decapeptide solution plus Tacrolimus 0.1% (M + T) Ointment versus Tacrolimus monotherapy 0.1% (T) Ointment in patients with stable vitiligo. The randomized, open label, comparative, prospective, multicentre study in patients with stable vitiligo was conducted. The primary endpoint was improvement in extent of repigmentation in target lesion after 12 months of treatment from baseline. The secondary endpoints were extent of repigmentation at end of 6 months, patient global assessment (PGA) and safety at end of 6 months. This shows interim analysis results. Total 94 patients were randomized to M + T (n = 40) and T (n = 44), 10 patients were lost to follow up. Extent of repigmentation (>50%) was significantly greater at end of 8 weeks in M + T group 22.5% (p ≤ .05) while 6.8% in T group. In grade of repigmentation, significant difference (p ≤ .05) was observed, M + T had better grade. PGA was significantly greater (p ≤ .05) in M + T‐group than T. All these parameters showed significant improvement in M + T‐group than group T at end of 6 months. No adverse events were reported during the study. It is an interim analysis report so complete data is not available for analysis. Addition of bFGF related decapeptide solution to Tacrolimus gave better results than Tacrolimus alone therapy. It also has a favorable safety profile and was well tolerated.  相似文献   
969.
970.
AIM:To evaluate the effect of resistance training(RT)on non alcoholic liver disease(NAFLD)patients.METHODS:A randomized clinical trial enrolling NAFLD patients without secondary liver disease(e.g.,without hepatitis B virus,hepatitis C virus or excessive alcohol consumption).Patients were randomly allocated either to RT,three times weekly,for 3 mo or a control arm consisting of home stretching.The RT included leg press,chest press,seated rowing,latissimus pull down etc.with 8-12 repetitions,3 sets for each exercise,for a total duration of 40 min.Hepatic ultrasound,fasting blood tests,anthropometrics and body composition by dual energy X-ray absorptiometry were assessed.At baseline and follow-up,patients filled out a detailed semi-quantitative food frequency questionnaire reporting their habitual nutritional intake.Steatosis was quantified by the hepatorenal-ultrasound index(HRI)representing the ratio between the brightness level of the liver and the right kidney.The HRI has been previously demonstrated to be highly reproducible and was validated against liver biopsy and proton magnetic resonance spectroscopy.RESULTS:Eighty two patients with primary NAFLD were randomized to receive 3 mo of either RT or stretching.After dropout or exclusion from analysis because of protocol violation(weight change>3 kg),thirty three patients in the RT arm and 31 in the stretching arm completed the study per protocol.All baseline characteristics were similar for the two treatment groups with respect to demographics,anthropometrics and body composition,blood tests and liver steatosis on imaging.HRI score was reduced significantly in the RT arm as compared to the stretching arm(-0.25±0.37 vs-0.05±0.28,P=0.017).The RT arm had a significantly higher reduction in total,trunk and android fat with increase in lean body mass.There was no correlation between the reduction in HRI in the RT arm and weight change during the study,but it was positively correlated with the change in trunk fat(r=0.37,P=0.048).The RT arm had a significant reduction in serum ferritin and total cholesterol.There was no significant difference between arms in dietary changes and these did not correlate with HRI change.CONCLUSION:Three months RT improves hepatic fat content accompanied by favorable changes in body composition and ferritin.RT may serve as a complement to treatment of NAFLD.  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