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   46篇
  免费   1篇
妇产科学   2篇
基础医学   8篇
口腔科学   2篇
临床医学   4篇
内科学   9篇
皮肤病学   2篇
神经病学   2篇
外科学   4篇
预防医学   8篇
药学   6篇
  2021年   1篇
  2015年   1篇
  2013年   1篇
  2012年   1篇
  2010年   4篇
  2009年   1篇
  2007年   1篇
  1999年   3篇
  1998年   3篇
  1997年   5篇
  1996年   5篇
  1994年   3篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1984年   2篇
  1982年   1篇
  1980年   2篇
  1974年   1篇
  1973年   1篇
  1967年   1篇
  1961年   1篇
排序方式: 共有47条查询结果,搜索用时 46 毫秒
1.
This report describes the use of photolysis and ozonolysis as a means of achieving complete cleavage of the pyridinium ring of (iso)desmosine in crosslinked elastin peptides. Although photolysis leads to the opening of the ring with concomitant formation of lysine, the peptide chains remain attached. Subsequent ozonolysis is able to completely achieve the cleavage of the rest of the ring skeleton, thus leading to the separation of the peptide chains. Formation of new amino acids, i.e. α-aminoadipic and glutamic acids, is emphasized. Localization of these amino acids within the released peptides should be of help in structural investigations on the crosslinking zones involving either isodesmosine or desmosine. However, other amino acids such as tyrosine and phenylalanine are sensitive to this procedure and side reactions occur which are responsible for peptide bond cleavage with the formation of breakdown products.  相似文献   
2.
BACKGROUND: Both cryosurgery, with and without prior curettage, and surgical excision (SE) are common therapeutic strategies for basal cell carcinoma (BCC). OBJECTIVE: The objective was to compare the efficacy between curettage plus cryosurgery (C&C) and SE in nonaggressive BCC of the head and neck. MATERIALS AND METHODS: A randomized controlled trial was carried out, in which tumors were assigned to either C&C (n=51) or SE (n=49). C&C was performed with a double freeze-thaw cycle after prior curettage of the tumor. SE was performed with a margin of 3 mm and with delayed histologic examination. RESULTS: Recurrences occurred 9 times after C&C (17.6%) and 4 times after SE (8.2%). The overall 5-year recurrence probability was 19.6% for C&C and 8.4% for SE (p=.10). A hazard ratio of 2.57 (95% CI, 0.79-8.34) indicated a putative, but not statistically significant, advantage of SE. CONCLUSION: These data reflect the outcome of the first randomized controlled trial with long-term follow-up in the treatment of BCC, comparing C&C with SE. Although not statistically significantly different, the observed differences could still be of clinical relevance. Owing to the trend toward lower recurrence rates, better cosmetic results, and reduced wound healing time, we believe that SE should be preferred to C&C in the treatment of primary, nonaggressive BCC of the head and neck.  相似文献   
3.
Background: The motives, objectives and design of a multicentreprospective study on job stress, absenteeism and coronary heartdisease in Europe (the JACE study) is presented in this paper.Some specific gaps in the reviewed literature are explicitlytapped into by the JACE study. Its objectives are i) to comparethe distributions of the Karasek job stress scales for the samebroad categories of occupations in different European countries(in males and females), ii) to study the predictive power ofthe job stress scales and the job strain model for one yearof sickness absence (in males and females) and iii) to studythe predictive power of the job stress scales and the job strainmodel for a three year incidence of coronary heart disease (Inmales only). Methods: In answering these questions, relationsare studied controlling for gender, age, level of education,company size, physical work risks and shift work, as well astraditional risk factors for CHD (i.e serum cholesterol, serumHDL cholesterol, smoking habits and blood pressure). The JACEstudy is a Biomed 1 concerted action. The JACE group consistsof eight participating centres from six countries, i.e. fromBelgium and Sweden (two centres), France, Italy, Spain, Swedenand The Netherlands (each one centre). The coordination of thegroup is in Brussels. The participating centres brought in over15, 000 European workers to test the hypotheses.  相似文献   
4.
In an attempt to achieve an anabolic response in both axial and peripheral bone, we treated twelve patients with osteoporosis using human 1-34 parathyroid peptide given discontinuously. The peptide was given as seven daily subcutaneous injections followed by 21 days' treatment with 0.25 mg calcitriol orally. This regime was repeated cyclically for at least sixteen cycles, of which the first four were at a lower dose of hPTH 1-34 than used subsequently. The results of treatment were monitored by kinetic, densitometric, histomorphometric and biochemical studies performed before and during treatment. Two patients developed hPTH 1-34 binding in their plasma during treatment: this was presumed to be due to the development of antibodies. The remainder, instead of increasing their indices of bone turnover as judged by iliac bone histomorphometry, were found to have consistent reductions in trabecular resorption surfaces. The other indices of bone formation and resorption measured showed no change or comparable reductions. The small increases seen in total body calcium were consistent with 'in-filling' of deleted basic multicellular units (BMUs). Because there is no evidence that calcitriol alone causes comparable reductions in activation of bone remodelling in osteoporosis, interruption of treatment with hPTH 1-34 after 7 days may have led to a failure of the activation mechanism to proceed to the resorption stage, with a consequent overall reduction in remodelling activity. This type of treatment regime, with its calcitonin-like effect, might be effective in reducing net bone loss due to imbalance between bone formation and resorption at the BMU level, particularly in patients with increased numbers of BMUs ('high turnover' osteoporosis).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
5.
6.
7.
A new handle usable for solid-phase peptide amide synthesis was designed. New releasing conditions of the peptide using sonication allowed much shorter reaction times at lower TFA concentrations.  相似文献   
8.
Aim The aim of this study was to assess the independent role of cerebral lesions on ultrasound scan, and several other neonatal and obstetric factors, as potential predictors of cerebral palsy (CP) in a large population‐based cohort of very preterm infants. Method As part of EPIPAGE, a population‐based prospective cohort study, perinatal data and outcome at 5 years of age were recorded for 1812 infants born before 33 weeks of gestation in nine regions of France in 1997. Results The study group comprised 942 males (52%) and 870 females with a mean gestational age of 30 weeks (SD 2wks; range 24–32wks) and a mean birthweight of 1367g (SD 393g; range 450–2645g). CP was diagnosed at 5 years of age in 159 infants (prevalence 9%; 95% confidence interval [CI] 7–10%), 97 males and 62 females, with a mean gestational age of 29 weeks (SD 2wks; range 24–32wks) and a mean birthweight of 1305g (SD 386g; range 500–2480g). Among this group, 67% walked without aid, 14% walked with aid, and 19% were unable to walk. Spastic, ataxic, and dyskinetic CP accounted for 89%, 7%, and 4% of cases respectively. The prevalence of CP was 61% among infants with cystic periventricular leukomalacia, 50% in infants with intraparenchymal haemorrhage, 8% in infants with grade I intraventricular haemorrhage, and 4% in infants without a detectable cerebral lesion. After controlling for cerebral lesions and obstetric and neonatal factors, only male sex (odds ratio [OR] 1.52; 95% CI 1.03–2.25) and preterm premature rupture of membranes or preterm labour (OR 1.72; 95% CI 0.95–3.14) were predictors of the development of CP in very preterm infants. Interpretation Cerebral lesions were the most important predictor of CP in very preterm infants. In addition, infant sex and preterm premature rupture of membranes or preterm labour were also independent predictors of CP.  相似文献   
9.
Pharmacological abnormalities occur in the psoriatic epidermis, and if similar abnormalities occur in the peripheral blood mononuclear cells they could impair the immune responses in psoriasis. In a paired control study, we have tested the capacity of histamine, isoprenaline and theophylline (10?5 and 10?7 M) to inhibit the mitogen responsiveness of blood mononuclear cells from normal and psoriatic subjects, using phytohaemagglutinin and concanavalin A. In the normal controls, mitogen responsiveness was inhibited by all three pharmacological agents by about 30 to 50%. In cells from psoriatic patients, the response in the presence of histamine was inhibited (as in the controls), but isoprenaline caused no inhibition, and theophylline paradoxically increased the mitogenic responses. These results suggest there is a defect in the pharmacological response of the blood mononuclear cells in psoriasis.  相似文献   
10.
The N-methyl-D-aspartate receptor/nitric oxide synthase (NOS)/guanylatecyclase pathway, which plays a crucial role in synaptic plasticityin the brain, is modulated by ethanol. We studied the effectof ethanol in vitro on NOS in rat cerebellum and showed thatethanol (25–200 mM) inactivated NOS in a dose-dependentmanner. This inactivation was prevented by the biopterin cofactortetrahydrobiopterin (BH4) as well as by L-arginine, a NOS substrate,but not by NADPH. These results suggest that ethanol reducesNOS activity by modulating the conformation of the enzyme andthereby its stability, probably by interacting with the bindingsites of BH4 and/or of L-arginine. Our data also suggest thatinactivation of NOS may contribute to the decrease in the cGMPlevel, and thus may play a role in the pharmacological actionsof ethanol in vivo.  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