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   196篇
  免费   6篇
  2023年   1篇
  2022年   1篇
  2021年   6篇
  2020年   1篇
  2019年   4篇
  2018年   4篇
  2016年   3篇
  2015年   6篇
  2014年   6篇
  2013年   5篇
  2012年   14篇
  2011年   32篇
  2010年   13篇
  2009年   3篇
  2008年   21篇
  2007年   14篇
  2006年   6篇
  2005年   13篇
  2004年   5篇
  2003年   10篇
  2002年   9篇
  2001年   1篇
  2000年   2篇
  1999年   6篇
  1998年   1篇
  1997年   3篇
  1993年   1篇
  1991年   2篇
  1988年   1篇
  1987年   2篇
  1984年   1篇
  1982年   1篇
  1981年   2篇
  1980年   1篇
  1974年   1篇
排序方式: 共有202条查询结果,搜索用时 15 毫秒
91.
The objective of this study was to compare noncontrast computed tomography (NCCT) and computed tomography perfusion (CTP) in early diagnosis of acute ischemic stroke and to define influence of these diagnostic procedures on early outcome of thrombolytic therapy (TLTH). The study included 45 patients, 35 patients submitted to NCCT and CTP and 10 patients who underwent only NCCT, before CTP was introduced. Based on the National Institute of Health Stroke Scale (NIHSS) score we compared early outcome of patients who received TLTH after NCCT only (group 1) with the early outcome of patients who received TLTH following NCCT and CTP (group 2). Statistically significant difference was found in acute stroke diagnosing between CTP and NCCT (p = 0.002). There were no statistically significant differences in TLTH early outcome between group 1 and group 2. In conclusion, CTP should be done regulary in patients presenting with acute ischemic stroke symptoms. More research needs to be done in defining exact influence of CTP implementation on the TLTH outcome.  相似文献   
92.
93.
94.
New polymeric copper(II) complexes with two tridentate ONS thiosemicarbazone ligands containing substituted pyrazolone moiety were synthesized and characterized by means of spectroscopic, electrochemical and crystallographic techniques. While both ligands exist as different tautomers in the solid state and DMSO-d6 solution, Cu(II) ion coordinates the ligands from the same tautomeric form with square-pyramidal geometry around each Cu atom. In the crystal structures, the copper(II) complex cation forms polymeric chains {[Cu(L)Cl]+}n with a bridging chlorine atom. One of the complexes was found to have a significantly higher cytotoxic potential in comparison with cisplatin in inhibition of several cell lines (HL60, REH, C6, L929 and B16). The results obtained on the basis of flow cytometry indicated that apoptosis could be possible mechanism of cell death.  相似文献   
95.
Autophagy is a highly regulated and evolutionarily conserved process of cellular self-digestion. Recent evidence suggests that this process plays an important role in regulating T cell homeostasis. In this study, we used Rag1(-/-) (recombination activating gene 1(-/-)) blastocyst complementation and in vitro embryonic stem cell differentiation to address the role of Beclin 1, one of the key autophagic proteins, in lymphocyte development. Beclin 1-deficient Rag1(-/-) chimeras displayed a dramatic reduction in thymic cellularity compared with control mice. Using embryonic stem cell differentiation in vitro, we found that the inability to maintain normal thymic cellularity is likely caused by impaired maintenance of thymocyte progenitors. Interestingly, despite drastically reduced thymocyte numbers, the peripheral T cell compartment of Beclin 1-deficient Rag1(-/-) chimeras is largely normal. Peripheral T cells displayed normal in vitro proliferation despite significantly reduced numbers of autophagosomes. In addition, these chimeras had greatly reduced numbers of early B cells in the bone marrow compared with controls. However, the peripheral B cell compartment was not dramatically impacted by Beclin 1 deficiency. Collectively, our results suggest that Beclin 1 is required for maintenance of undifferentiated/early lymphocyte progenitor populations. In contrast, Beclin 1 is largely dispensable for the initial generation and function of the peripheral T and B cell compartments. This indicates that normal lymphocyte development involves Beclin 1-dependent, early-stage and distinct, Beclin 1-independent, late-stage processes.  相似文献   
96.
The aim of this study was to present our experiences in diagnosing spondyloarthritides (SpA), and to list the most common clinical features of HLA-B27 positive patients. The study included 65 HLA-B27 positive patients with confirmed diagnosis of ankylosing spondylitis (AS) and psoriatic arthritis (PsA) who were analyzed between 2009 and 2010 in Clinic of Internal Medicine in Osijek. The diagnosis of seronegative spondyloarthritides was based on the ASAS (Assessment in AS Working Group) classification criteria for axial and then supplemented with ASAS criteria for peripheral SpA and was confirmed by radiological techniques. For diagnosing the ankylosing spondylitis (AS), there have been applied the modified New York criteria. Radiological criteria for definite sacroiliitis according to the modified New York criteria is bilateral sacroiliitis, grade 2-4 (> or = 2) or unilateral sacroiliitis, grade 3-4. For diagnosing the psoriatic arthritis (PsA), there were used CASPAR diagnostic criteria. Other features of SpA are defined within the existing classification criteria. HLA-B27 antigen was determined by direct immune-fluorescence technique using flow cytometer. The average age of patients was 50.34 years, of whom 27 female (41.53%), 38 male (58.46%). Duration of illness was 15.79 years on average. With 75.38% of patients, there had been determined the diagnosis of AS; 24.62% of patients had the diagnosis of PsA. The most common clinical characteristics that patients had were: inflammatory back pain (pain Inflammation along the lumbosacral spine), peripheral arthritis, intermittent pain in the gluteus, sacroiliitis, enthesitis, uveitis, dactilitis.  相似文献   
97.
The renin-angiotensin system is involved in the progression of chronic renal disease of both diabetic and nondiabetic origin. The angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers have been demonstrated to reduce urinary protein excretion and attenuate the development of renal injury. This prospective, randomized, 12-month study assessed the effects of ramipril (N = 23) vs. valsartan (N = 22) vs. combination of ramipril and valsartan (N = 26) on proteinuria, renal function and metabolic profile in 71 patients with nondiabetic proteinuria with normal or slightly impaired renal function. Monotherapy with ramipril or valsartan and combination of these two drugs significantly reduced proteinuria, serum creatinine, cholesterol and triglycerides as well as systolic and diastolic arterial blood pressure. There was no significant difference among three study groups according to reduction of arterial blood pressure, serum cholesterol and triglycerides. At one year, a significant reduction in serum creatinine was recorded in all three study groups, whereas at 3 and 6 months a statistically significant reduction in serum creatinine was only observed in patients on combination therapy. In addition, at 3 months the reduction of proteinuria was significantly greater in patients on combination therapy than in those on either monotherapy. These results indicated the combination therapy with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers to be more efficacious than either monotherapy in reducing proteinuria and serum creatinine level in the first 3 (proteinuria and serum creatinine) or 6 (serum creatinine) months of treatment.  相似文献   
98.
Despite the already established route of chemically catalyzed transesterification reaction in biodiesel production, due to some of its shortcomings, biocatalysts such as lipases present a vital alternative. Namely, it was noticed that one of the key shortcomings for the optimization of the enzyme catalyzed biodiesel synthesis process is the information on the lipase activity in the reaction mixture. In addition to making optimization difficult, it also makes it impossible to compare the results of the independent research. This article shows how lipase intended for use in biodiesel synthesis can be easily and accurately characterized and what is the enzyme concentration that enables achievement of the desired level of fatty acid methyl esters (FAME) in the final product mixture. Therefore, this study investigated the effect of two different activity loads of Burkholderia cepacia lipase on the biodiesel synthesis varying the pH and temperature optimal for lipase activity. The optimal lipase pH and temperature were determined by two different enzyme assays: spectrophotometric and titrimetric. The B. cepacia lipase pH optimum differentiated between assays, while the lipase optimally hydrolyzed substrates at 50°C. The analysis of FAME during 24 hr of biodiesel synthesis, at two different enzyme concentrations, pH 7, 8, and 10, and using two different buffers, revealed that the transesterification reaction at optimal pH, 1 hr reaction time and lipase activity load of 250 U per gram of reaction mixture was sufficient to produce more than 99% FAME.  相似文献   
99.
Interest for breeding mouflons in Europe is growing by the day, so it is important to extend our knowledge regarding their physiology. To establish reference intervals of biochemical values for mouflon (Ovis orientalis musimon), serum samples from 35 males and 26 females were analyzed using the automatic analyzer Olympus AU 640 for 22 serum biochemistry parameters. All mouflons aged from 1 to 4 years were apparently healthy and in good body condition and kept at an average altitude of 87 m (45°4′N, 18°6′E). Obtained results were tested according to age and sex categories by the repeated measurement model with Tukey’s post hoc test. Data showed a significantly higher (P < 0.01) concentration of total serum bilirubin and chloride in adult pregnant female mouflons compared to adult male mouflons. A significantly higher (P < 0.01) value of sodium and a lower (P < 0.01) value of serum phosphate in adult pregnant female mouflons compared to adult male mouflons have been determined. These data provide the baseline information about serum biochemical parameters which can be used to manage the health in mouflons.  相似文献   
100.
A joint analysis of five paternal half-sib Holstein families that were part of two different granddaughter designs (ADR- or Inra-design) was carried out for five milk production traits and somatic cell score in order to conduct a QTL confirmation study and to increase the experimental power. Data were exchanged in a coded and standardised form. The combined data set (JOINT-design) consisted of on average 231 sires per grandsire. Genetic maps were calculated for 133 markers distributed over nine chromosomes. QTL analyses were performed separately for each design and each trait. The results revealed QTL for milk production on chromosome 14, for milk yield on chromosome 5, and for fat content on chromosome 19 in both the ADR- and the Inra-design (confirmed within this study). Some QTL could only be mapped in either the ADR- or in the Inra-design (not confirmed within this study). Additional QTL previously undetected in the single designs were mapped in the JOINT-design for fat yield (chromosome 19 and 26), protein yield (chromosome 26), protein content (chromosome 5), and somatic cell score (chromosome 2 and 19) with genomewide significance. This study demonstrated the potential benefits of a combined analysis of data from different granddaughter designs.  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