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   74篇
  免费   3篇
妇产科学   6篇
基础医学   8篇
临床医学   3篇
内科学   19篇
皮肤病学   12篇
神经病学   5篇
特种医学   2篇
外科学   8篇
预防医学   5篇
药学   4篇
中国医学   1篇
肿瘤学   4篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   3篇
  2019年   1篇
  2018年   1篇
  2017年   6篇
  2016年   2篇
  2015年   1篇
  2014年   2篇
  2013年   6篇
  2012年   8篇
  2011年   10篇
  2010年   4篇
  2009年   1篇
  2008年   6篇
  2007年   3篇
  2006年   9篇
  2004年   3篇
  2003年   1篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1989年   1篇
  1986年   1篇
  1967年   1篇
排序方式: 共有77条查询结果,搜索用时 31 毫秒
1.
The immunoreactivity of various LH and FSH calibration standards and recombinant preparations in the enzyme-linked immunoassay (EIA) systems for gonadotrophins developed for the Special Programme of Research in Human Reproduction of the World Health Organization (WHO) were compared. The preparations tested included three LH and two FSH pituitary standards (calibrated against LH 80/552 and 68/40 and FSH 78/549 respectively) provided with the EIA or radioimmunoassay WHO matched reagent kits, the pituitary preparation LER-907, and recombinant human LH (rhLH) and FSH (rhFSH). Simultaneous curve fitting of the EIA dose-response curves revealed no significant differences among the slopes generated by the WHO LH standards and LER-907; in contrast, no parallelism was found between the curves of rhLH and the pituitary-derived LH standards. No significant differences were found among the slopes of the curves elicited by the pituitary and recombinant FSH preparations. Each LH preparation exhibited a high degree of charge heterogeneity. Considerable variations in charge isoform distribution among the WHO LH standards, rhLH and LER-907 were also evident. In contrast, the FSH preparations were less heterogeneous and exhibited minor differences in charge distribution. Despite the existing differences in charge isoform distribution, all the pituitary-derived preparations as well as rhFSH seem appropriate for using as calibration standards in this particular EIA system.  相似文献   
2.
Vitamin D insufficiency, as measured by 25‐hydroxyvitamin D (25[OH]D) levels, has been associated with important health outcomes. The majority of vitamin D in circulation is bound to vitamin D–binding protein (DBP) and albumin, and recent genetic studies have demonstrated that serum DBP is a major determinant of 25(OH)D concentrations in adults. The impact of circulating DBP levels on vitamin D's biologic action, is unclear, but is of particular relevance to vitamin D epidemiology, because a lack of control for DBP levels could strongly influence the association of vitamin D with disease. Serum parathyroid hormone (PTH) levels can act as a biological readout of 25(OH)D activity. We therefore assessed the relationship between serum total and free 25(OH)D and PTH with and without adjusting for DBP, in 2073 subjects of European descent. Total 25(OH)D levels correlated positively (r = 0.19, p = 1.8 × 10?17) with DBP, whereas the free 25(OH)D correlated negatively (r = ?0.14, p = 5.0 × 10?12). Total and free 25(OH)D levels correlated negatively with PTH (r = ?0.29, p = 1.3 × 10?39; r = ?0.26, p = 1.9 × 10?33, respectively). Including age, body mass index (BMI), sex, estimated glomerular filtration rate, calcium, and season of blood draw as covariates, total 25(OH)D levels were significantly associated with log‐transformed PTH (lnPTH) levels (linear term: β = ?0.010, p < 0.0001, squared term: β = 0.00004, p < 0.0001) and this association was not changed by adjusting for DBP. These findings provide evidence that in a largely vitamin D–sufficient cohort, the biological effect of vitamin D on PTH levels is mainly independent of DBP concentration. Accordingly, this study may provide useful information for studies investigating the relationship between vitamin D, DBP, and disease. © 2014 American Society for Bone and Mineral Research.  相似文献   
3.
Alterations in the reproductive axis function are present to a variable extent in patients with type 1 diabetes mellitus (IDDM). Results from studies in IDDM men have yielded discrepant findings, which may reflect nonuniform patient selection criteria, age, diabetic status, duration of the disease and differences in sampling protocols. To more clearly define the impact of early diabetic alterations in the male reproductive axis, we applied a combined strategy of patient selection restricted to young men with relatively short duration of IDDM, dual control groups, multiparameter deconvolution analysis to assess LH secretory activity, and assessment of time-dependent changes in human chorionic gonadotropin (hCG)-stimulated serum testosterone concentrations. Three groups of subjects were studied: 11 young men with poorly controlled IDDM, 9 well controlled diabetics, and 9 healthy men. All volunteers underwent blood sampling at 10-min intervals before and after 2 consecutive iv pulses of 10 micro g GnRH. On a separate day, 40 IU/kg hCG were given im, and blood samples were collected before hCG administration, every 60 min thereafter for 6 h, and then 24, 48, and 72 h after the injection. Mean serum LH concentrations across the basal 6-h sampling period were significantly (P < 0.05) decreased in men with poorly controlled IDDM (11 +/- 1.6 IU/liter) compared with those in well controlled diabetics (19 +/- 1.8 IU/liter) and healthy controls (19 +/- 1.5 IU/liter). Multiple parameter deconvolution analysis revealed a 50% reduction in the mass of LH secreted per burst and the pulsatile LH secretion rate in poorly controlled IDDM (mass of LH secreted/burst, 7 +/- 1.1 vs. 12 +/- 2.1 and 13 +/- 1.5 IU/liter; LH secretion rate, 47 +/- 6.3 vs. 78 +/- 10 and 87 +/- 11 IU/liter.6 h; poorly controlled vs. well controlled IDDM and healthy controls, respectively; P < 0.05 for both parameters). Uncontrolled IDDM patients had significantly (P < 0.05) lower integrated serum LH concentrations after the first and second GnRH pulses (first GnRH pulse, 4460 +/- 770 vs. 7250 +/- 1200 and 5120 +/- 910 IU/liter; second pulse, 4700 +/- 615 vs. 7640 +/- 881 and 7100 +/- 1230 IU/liter; poorly controlled vs. well controlled IDDM and healthy men, respectively) and markedly attenuated LH secretory burst mass after the second GnRH stimulus (49 +/- 8.8 vs. 90 +/- 13 and 83 +/- 19 IU/liter; poorly controlled vs. well controlled IDDM and healthy controls, respectively). The biological to immunological ratio of LH released in baseline conditions was higher in uncontrolled IDDM patients (0.81 +/- 0.10) than in controlled IDDM (0.37 +/- 0.08) and healthy controls (0.48 +/- 0.06; P < 0.01), whereas LH released in response to exogenous GnRH exhibited comparable ratios among the three study cohorts. Baseline serum testosterone levels as well as absolute and incremental responses to exogenous hCG did not differ by degree of metabolic control. Collectively, these results indicate that the function of the hypothalamic-gonadotrope axis is compromised in young men with poorly controlled IDDM, such that the amplitude of spontaneous pulsatile and exogenous GnRH-stimulated LH secretion is attenuated. This central hypogonadotropism is paradoxically associated with the presence in the circulation of gonadotropin molecules with enriched biological activity, which is evidently sufficient to temporarily maintain normal total testosterone concentrations in the earlier stages of IDDM.  相似文献   
4.
5.
17β-Estradiol (E2) rapidly, by binding to membrane estrogen receptors, activates cell signaling cascades which induce formation of new dendritic spines in the hippocampus of males as in females, but the interaction with other metabolic processes, such as extracellular adenine nucleotides metabolism, are currently unknown. Extracellular adenine nucleotides play significant roles, controlling excitatory glutamatergic synapses and development of neural circuits and synaptic plasticity. Their precise regulation in the synaptic cleft is tightly controlled by ecto-nucleoside triphosphate diphosphohydrolase (NTPDase)/ecto-5′-nucleotidase (eN) enzyme chain. Therefore, we sought to clarify whether a single systemic injection of E2 in male rats is accompanied by changes in the expression of the pre- and postsynaptic proteins and downstream kinases linked to E2-induced synaptic rearrangement as well as alterations in NTPDase/eN pathway in the hippocampal synaptosomes. Obtained data showed activation of mammalian target of rapamycin and upregulation of key synaptic proteins necessary for spine formation, 24 h after systemic E2 administration. In E2-mediated conditions, we found downregulation of NTPDase1 and NTPDase2 and attenuation of adenine nucleotide hydrolysis by NTPDase/eN enzyme chain, without changes in NTPDase3 properties and augmentation of synaptic tissue-nonspecific alkaline phosphatase (TNAP) activity. Despite reduced NTPDase activities, increased TNAP activity probably prevents toxic accumulation of ATP in the extracellular milieu and also hydrolyzes accumulated ADP due to unchanged NTPDase3 activity. Thus, our initial evaluation supports idea of specific roles of different ectonucleotidases and their coordinated actions in E2-mediated spine remodeling and maintenance.  相似文献   
6.
Information on the impact of prolonged deficient glycemic control in the quality of the gonadotropin signal delivered by the pituitary gland during puberty in children with insulin-dependent diabetes mellitus (IDDM) is scarce. In the present study, we examined the impact of deficient glycemic control on bioactive LH and FSH concentrations and their corresponding biological-to-immunological (B:I) ratio in boys with poorly controlled, but systemically uncomplicated IDDM. Dual control groups comprising patients with well-controlled IDDM and healthy boys of comparable age and body mass index were included for appropriate comparisons within and between each pubertal stage. Patients with poorly controlled and well-controlled IDDM exhibited serum bioactive FSH levels and B:I FSH ratio similar to those showed by the healthy control group. In contrast, in early and mid-pubertal boys with poorly controlled IDDM bioactive LH levels were normal, but its B:I LH relationship was significantly (P < 0.05) decreased. This attenuation in the quality of the LH signal did not affect total serum T concentrations, and apparently, progression of puberty. Long-standing uncontrolled diabetes and the consequent metabolic disturbances and/or complications may aggravate the reproductive axis dysfunction and eventually provoke pubertal arrest.  相似文献   
7.
Background Human Herpesvirus type 8 (HHV‐8) is a new member of the herpes virus family, first found in the tissue of acquired immune deficiency syndrome (AIDS)‐related Kaposi’s sarcoma. Environmental factors including viral infection may play a role in the onset and/or development of pemphigus. Some studies based on polymerase chain reaction findings suggest an association between HHV‐8 and pemphigus. The aim of this study is investigation of the association of pemphigus with HHV‐8 and the relationship between inflammatory and acantholytic cells with HHV‐8 infection. Methods Tissue‐extracted DNA from 41 paraffin‐embedded skin tissues from patients first presenting with pemphigus was tested using nested PCR for the presence of HHV‐8. A total of 37 cases had pemphigus vulgaris (PV) and 4 patients had pemphigus foliaceus (PF). For our control group, normal skin of 21 cosmetic surgery patients were included. Furthermore, microscopic slides with H&E staining were evaluated for the number of inflammatory and acantholytic cells per microscopic field. Results Skin lesions from 13 of 37 patients (35.1%) with PV and 2 of 4 cases (50%) with PF were positive for HHV‐8 DNA. All specimens in our control group were negative for this virus. Conclusion HHV‐8 infection might be a contributing factor in the initiation or development of pemphigus.  相似文献   
8.
The molecular causes of severe high-density lipoprotein cholesterol (HDL-C) deficiency was examined in a group of 54 unrelated French Canadian subjects. The lecithin:cholesterol acyl transferase (LCAT) and apolipoprotein (apo) A-I gene were analyzed in all probands by direct DNA sequencing. While no LCAT mutation was detected, a novel nonsense apoA-I mutation (E136X) was found in 3/54 probands. Genetic analysis of two kindreds showed a strong co-segregation of the apoA-I locus with the low HDL-C trait. The E136X mutation was detected in families by MaeI restriction digestion. E136X carriers (n=17) had marked HDL-C deficiency; among the nine carriers > or = 35 years old, five men had developed premature coronary artery disease (CAD). A peptide of apparent molecular weight of 14 kDa was identified in fresh plasma, the HDL fractions and lipoprotein deficient plasma from the three probands but not in normal controls (n=3), suggesting that the mutant apoA-I peptide is secreted and binds lipids. The mutation was not observed in an additional 210 chromosomes from unrelated subjects of French Canadian descent, < 60 years of age, with CAD and low HDL-C levels. We conclude that apoA-I (E136X) is a cause of HDL-C deficiency in the French Canadian population and is associated with premature CAD.  相似文献   
9.
BACKGROUND/AIM. Colorectal cancer (CRC) is one of the biggest health problems of modern humanity, especially in highly developed countries. In Serbia about 3,200 patients suffer from CRC, out of whom about 1,100 patients suffer from rectal cancer (RC), while about 2,100 patients suffer from other colon segments cancer. The aim of the study was to show the incidence genesis of one of the possible early postoperative complications regarding dehiscence of the colorectal anastomosis (CRA) with a group of patients suffering from RC and operated by using sphincter-saving procedures, in the period from 1993 to 2007, and then to compare the incidence genesis of these complications with those in the published series of the reporting colorectal institutions. METHODS: The research included 242 patients radically operated on for RC in a 15-year period using some of sphincter-saving procedures following by a careful analysis of the symptoms of subclinical dehyscencias not solved with the reintervention as well as of the clinically evidented dehyscencias mostly solved by reoperation. RESULTS: With 22 (9.1%) patients in the first 10 postoperative days there were early postoperative symptoms of CRA dehiscence. In 6 (2.47%) of the patients there were subclinical signs of raised body temperature, less quantity of feces content, and after the conservative treatment they ended in spontaneous process of rehabilitation. In 16 (6.61%) patients there was clinically evidented anastomosis dehiscence followed by abundant drainage of feces content, signs of local peritonitis, pelvic sepsis, so we had to undertake surgical intervention. CONCLUSION. Comparing the results of a few tenths of published studies with our results we proved that performing and operative technique of colorectal anastomosis in the patients suffered and radically surgically treated for RC, is quite adequate with the operative technique in reporting world institutions that are engaged in surgical treatment of RC.  相似文献   
10.
Respect for personal autonomy in decision-making is one of the four ethical principles in medical circumstances. This paper aims to present evidence that can be considered good exemplars in the clarification of the ethical viewpoints of the western and Shi’i Islamic perspectives on this issue. The method followed was originally a search in international indexing services in April 2016. Our findings point towards various controversies on individuals’ autonomy lead to different decision making outcomes by health workers in both different traditions. We concluded that although Shi’i Islamic jurisprudence does not seem to allow for personal autonomy in the sense it is understood in a western context, evidence indicates that Shi’i Islamic jurisprudence respects personal autonomy.  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