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   485篇
  免费   21篇
  国内免费   4篇
耳鼻咽喉   6篇
儿科学   11篇
妇产科学   11篇
基础医学   58篇
口腔科学   48篇
临床医学   31篇
内科学   84篇
皮肤病学   6篇
神经病学   17篇
特种医学   10篇
外科学   70篇
综合类   5篇
预防医学   44篇
眼科学   10篇
药学   70篇
肿瘤学   29篇
  2023年   5篇
  2022年   11篇
  2021年   16篇
  2020年   7篇
  2019年   10篇
  2018年   13篇
  2017年   11篇
  2016年   15篇
  2015年   15篇
  2014年   12篇
  2013年   24篇
  2012年   31篇
  2011年   47篇
  2010年   27篇
  2009年   14篇
  2008年   28篇
  2007年   35篇
  2006年   28篇
  2005年   27篇
  2004年   28篇
  2003年   25篇
  2002年   18篇
  2001年   8篇
  2000年   6篇
  1999年   9篇
  1998年   4篇
  1997年   1篇
  1996年   2篇
  1994年   1篇
  1992年   2篇
  1991年   5篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   5篇
  1986年   3篇
  1985年   2篇
  1984年   4篇
  1983年   2篇
  1982年   2篇
  1977年   1篇
  1976年   1篇
  1972年   1篇
  1966年   1篇
排序方式: 共有510条查询结果,搜索用时 46 毫秒
1.
We describe a large inbred Sicilian family that includes four 46, XX (SRY-) brothers. Palmoplantar hyperkeratosis (PPK) and an associated predisposition to squamous cell carcinoma (SCC) of the skin, segregates as a recessive trait within the family. Interestingly, all the PPK-affected members of the family are phenotypic males (46,XY or 46,XX) while seven XX sibs are healthy phenotypic females with no signs of PPK. We propose that homozygosity for a single mutational event, possibly including contiguous genes, may cause PPK/SCC in both XY or XX individuals and sex reversal in XX individuals. The family is informative for linkage analysis for the PPK trait and allows linkage exclusion for the sex reversal trait. Here we show that 15 loci involved in PPK etiology, skin differentiation, function or malignancy, and nine loci involved in sex determination/differentiation are not implicated in the phenotype of this family.  相似文献   
2.
Severe obesity is associated with an increased risk of admission to intensive care units and need for invasive mechanical ventilation in patients with COVID-19. The association of obesity and COVID-19 prognosis may be related to many different factors, such as chronic systemic inflammation, the predisposition to severe respiratory conditions and viral infections. The ketogenic diet is an approach that can be extremely effective in reducing body weight and visceral fat in the short term, preserving the lean mass and reducing systemic inflammation. Therefore, it is a precious preventive measure for severely obese people and may be considered as an adjuvant therapy for patients with respiratory compromise.  相似文献   
3.
Healthy blood donors from the city of Zagreb were checked for the presence of a nephrotoxic mycotoxin ochratoxin A (OTA) in the plasma. Samples of blood were collected in June, September, and December 1997, and March 1998, totalling 200 or 50 in each round. The concentrations of OTA were measured using high pressure liquid chromatography (HPLC) method (detection limit 0.2 ng OTA/ml of plasma). The frequency of OTA-positive samples (> 0.2 ng/ml of plasma) showed significant seasonal variation (P < 0.001). The frequency of OTA-positive samples was the highest in March (65%) and it gradually decreased towards December (12%). The high frequency of positive samples coincided with seasons favouring growth of moulds and production of toxins. The daily intake of OTA by healthy persons in Zagreb was estimated from the mean concentration of OTA in samples collected during the whole year (0.19 ng OTA/ml plasma). The estimated daily intake was 0.26 ng/kg b.w., that is, substantially below the tolerable daily intake proposed by World Health Organization (16.0 ng/kg b.w.).  相似文献   
4.
5.
Optimization of an elastic tissue histochemical stain to enable clear, crisp visualization and quantification of pulmonary small vasculature is central to the histomorphologic quantitation of pulmonary vasculature wall thickness. To accomplish elastic tissue histochemical stain optimization, five histochemical elastin stains were compared to identify the internal and external elastic laminae of small arteries (50–100 μm in external diameter) to very small intra-acinar vessels (10–50 μm in external diameter) in rat lung tissue sections. The five elastin stains included: a modified Verhoeff’s elastin stain, Miller’s elastic van Gieson, and three modifications of the Miller’s stain. The Miller elastin stain is a progressive procedure that does not require a differentiation step, thus enabling consistency and reliability of staining from slide to slide. A modified Miller’s histochemical staining methodology successfully highlighted the pulmonary small caliber vasculature wall thickness. The modified method was technically easier and less time consuming to perform than regressive methods. To improve elastin-to-background contrast, modifications to the Miller’s stain included bypassing the nuclear staining and using a neutral red counterstain in place of the van Gieson counterstain, both of which greatly facilitated observer-assisted pulmonary vascular structure identification for histomorphometric quantitation.  相似文献   
6.
Kawasaki disease (KD) is an acute, self-limited vasculitis of unknown etiology that occurs predominantly in infants and children younger than 5 years of age. Coronary artery abnormalities are the most serious complication.Based on the literatures infusion of Intravenous Immunoglobulin of 2 g/kg and a high dose of oral aspirin up to 100 mg/kg/day are the standard treatment for Kawasaki disease in the acute stage, and should be followed by antiplatelet dose of aspirin for thrombocytosis. Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is an inherited X-linked hereditary disorder, and aspirin can induce hemolysis in patients with G6PD deficiency. We report a case of a 5 year and 8 month old male with KD and G6PD deficiency.  相似文献   
7.
Pain after spinal cord injury (SCI-Pain) is one of the most debilitating sequelae of spinal cord injury, characterized as relentless, excruciating pain that is largely refractory to treatments. Although it is generally agreed that SCI-Pain results from maladaptive plasticity in the pain processing pathway that includes the spinothalamic tract and somatosensory thalamus, the specific mechanisms underlying the development and maintenance of such pain are yet unclear. However, accumulating evidence suggests that SCI-Pain may be causally related to abnormal thalamic disinhibition, leading to hyperactivity in the posterior thalamic nucleus (PO), a higher-order nucleus involved in somatosensory and pain processing. We previously described several presynaptic mechanisms by which activity in PO is regulated, including the regulation of GABAergic as well as glutamatergic release by presynaptic metabotropic gamma-aminobutyric acid (GABAB) receptors. Using acute slices from a mouse model of SCI-Pain, we tested whether such mechanisms are affected by SCI-Pain. We reveal 2 abnormal changes in presynaptic signaling in the SCI-Pain condition. The substantial tonic activation of presynaptic GABAB receptors on GABAergic projections to PO—characteristic of normal animals—was absent in mice with SCI-Pain. Also absent in mice with SCI-Pain was the normal presynaptic regulation of glutamatergic projections to the PO by GABAB receptors. The loss of these regulatory presynaptic mechanisms in SCI-Pain may be an element of maladaptive plasticity leading to PO hyperexcitability and behavioral pain, and may suggest targets for development of novel treatments.

Perspective

This report presents synaptic mechanisms that may underlie the development and maintenance of SCI-Pain. Because of the difficulty in treating SCI-Pain, a better understanding of the underlying neurobiological mechanisms is critical, and may allow development of better treatment modalities.  相似文献   
8.
The 1,3-dipolar cycloaddition reaction between unactivated azides and acetylenes proceeds exceedingly slowly at room temperature. However, considerable rate acceleration is observed when this reaction occurs inside the active center gorge of acetylcholinesterase (AChE) between certain azide and acetylene reactants, attached via methylene chains to specific inhibitor moieties selective for the active center and peripheral site of the enzyme. AChE catalyzes the formation of its own inhibitor in a highly selective fashion: only a single syn1-triazole regioisomer with defined substitution positions and linker distances is generated from a series of reagent combinations. Inhibition measurements revealed this syn1-triazole isomer to be the highest affinity reversible organic inhibitor of AChE with association rate constants near the diffusion limit. The corresponding anti1 isomer, not formed by the enzyme, proved to be a respectable but weaker inhibitor. The crystal structures of the syn1- and anti1-mouse AChE complexes at 2.45- to 2.65-A resolution reveal not only substantial binding contributions from the triazole moieties, but also that binding of the syn1 isomer induces large and unprecedented enzyme conformational changes not observed in the anti1 complex nor predicted from structures of the apoenzyme and complexes with the precursor reactants. Hence, the freeze-frame reaction offers both a strategically original approach for drug discovery and a means for kinetically controlled capture, as a high-affinity complex between the enzyme and its self-created inhibitor, of a highly reactive minor abundance conformer of a fluctuating protein template.  相似文献   
9.
Syntaxin 11 (STX11) controls vesicular trafficking and is a key player in exocytosis. Since Stx11 mutations are causally associated with a familial hemophagocytic lymphohistio‐cytosis, we wanted to clarify whether STX11 is functionally important for key immune cell populations. This was studied in primary cells obtained from newly generated Stx11?/? mice. Our data revealed that STX11 is not only widely expressed in different immune cells, but also induced upon LPS or IFN‐γ treatment. However, Stx11 deficiency does not affect macrophage phagocytic function and cytokine secretion, mast cell activation, or antigen presentation by DCs. Instead, STX11 selectively controls lymphocyte cytotoxicity in NK and activated CD8+ T cells and degranulation in neutrophils. Stx11?/? NK cells and CTLs show impaired degranulation, despite a comparable activation, maturation and expression of the complex‐forming partners MUNC18–2 and VTI1B. In addition, Stx11?/? CTLs and NK cells produce abnormal levels of IFN‐γ. Since functional reconstitution rescues the defective phenotype of Stx11?/? CTLs, we suggest a direct, specific and key role of STX11 in controlling lymphocyte cytotoxicity, cytokine production and secretion. Finally, we show that these mice are a very useful tool for dissecting the role of STX11 in vesicular trafficking and secretion.  相似文献   
10.
The Croatian Institute of Public Health (CIPH) collects health care related statistical data based on the Republic of Croatia''s Annual Plan of Implementation of Statistical Activities. The purpose of this study was to analyse the CIPH data retrieved from annual reports, obtained from contractual teams and institutions related to dental medicine activities, collected in respective counties and for the entire country. Material and methods: The data were collected from the Croatian Statistical Health Care Yearbook for the period from 2009 to 2013. Results: The analysis has shown the increase in the number of insured persons (5%), but the decrease in the number of persons who received care (10%) and the increase in the number of visits (14%) and general examinations (13%). The majority of the beneficiaries were from the City of Zagreb with the highest number of visits, but with a low number of general examinations included in these visits (11%); while the Zadar County had the highest number of general examinations in terms of dental health care users (90.6%) and the proportion of general examinations in visits (30%). The most common diagnosis was dental caries (43%). The incomplete and insufficient reporting from some counties, inadequate recording of diagnoses and of curative and preventive procedures could be the factors affecting the quantity and quality of obtained data. Proper and regular submissions of reports to counties'' public health institutes, regular preventive examinations, adequate recording of diagnoses and procedures would contribute positively to further health planning and the implementation of preventive measures for the improvement of oral health. Conclusion: The data analysis gives an insight into the current situation allowing on such basis further planning and conducting of activities at national and local level. Further analyses would help to get a better perspective and improvement of dental medicine activities.Key words: Dental Health Surveys, Public Health Dentistry, Health Policy, National Health Programs, Observer Variation, Health Planning, Data Interpretation, Statistical  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