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   410篇
  免费   35篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   17篇
妇产科学   5篇
基础医学   53篇
口腔科学   8篇
临床医学   42篇
内科学   105篇
神经病学   19篇
特种医学   7篇
外科学   38篇
综合类   2篇
预防医学   76篇
眼科学   25篇
药学   27篇
肿瘤学   22篇
  2022年   2篇
  2021年   11篇
  2020年   3篇
  2019年   7篇
  2018年   13篇
  2017年   13篇
  2016年   13篇
  2015年   11篇
  2014年   13篇
  2013年   28篇
  2012年   31篇
  2011年   37篇
  2010年   14篇
  2009年   23篇
  2008年   28篇
  2007年   33篇
  2006年   32篇
  2005年   26篇
  2004年   31篇
  2003年   11篇
  2002年   12篇
  1999年   2篇
  1996年   1篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1991年   6篇
  1990年   3篇
  1989年   1篇
  1988年   5篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
  1984年   1篇
  1982年   2篇
  1981年   2篇
  1979年   1篇
  1977年   1篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1971年   1篇
  1969年   4篇
  1968年   1篇
  1966年   3篇
  1965年   2篇
  1934年   2篇
  1933年   1篇
  1931年   1篇
  1930年   1篇
排序方式: 共有447条查询结果,搜索用时 15 毫秒
11.
To assess whether magnesium treatment in patients with subarachnoid haemorrhage (SAH) is associated with hypocalcaemia and whether hypocalcaemia in these patients is associated with an increased risk of delayed cerebral ischemia (DCI) and poor outcome. All 137 patients randomized in the clinically controlled "Magnesium in Aneurysmal Subarachnoid Haemorrhage" trial were included. The relationship between mean serum magnesium and mean serum calcium during treatment was assessed with linear regression. The relationship between hypocalcaemia (serum calcium < 2.0 mmol/L) during treatment and the occurrence of DCI and poor outcome was studied with the Cox proportional hazards method and logistic regression, respectively. There was a statistically significant inverse relation between elevated serum magnesium and hypocalcaemia (B = -0.27; 95% CI, -0.33 to -0.20; p < 0.001). Patients with hypocalcaemia during study treatment had an increased frequency of DCI (HR 2.1; 95% CI, 1.0 to 4.3), and an increased risk for poor outcome (OR 2.9; 95% CI, 1.4 to 6.4), but this effect attenuated in the multivariable analysis (OR 1.9; 95% CI, 0.8 to 4.7). In conclusion, prolonged elevated serum magnesium is associated with hypocalcaemia. Hypocalcaemia is associated with an increased risk of DCI and poor outcome and may therefore reduce the potential beneficial effect of magnesium treatment in SAH.  相似文献   
12.
Dendritic cells (DC) play an important role in immune responses and have been studied extensively in human and mouse models. CD40 triggering of DC has a pivotal role in their maturation process, obtaining the unique capacity to induce strong CD4 and CD8 T cell activation. Although rat models are frequently used for the understanding of the underlying mechanism of human diseases, relatively little is known about rat DC. To investigate the effect of CD40 triggering on rat DC, we cloned the rat CD40L gene and generated murine fibroblasts with stable expression (L-rCD40L). DC stimulated by L-rCD40L cells exhibited a strong T cell stimulatory capacity, associated with higher amounts of IFN-gamma as compared to LPS-stimulated DC. Analysis of cytokine production showed that LPS induced both IL-12 and IL-10 production, whereas CD40L induced high amounts of IL-12, but little IL-10 production by rat DC. This implies that the difference found in T cell stimulatory capacity by the stimulated DC is due to the cytokine profile of the DC at the time of T cell activation.  相似文献   
13.
Pathogen‐derived entities force the tissue‐resident dendritic cells (DCs) towards a mature state, followed by migration to the draining lymph node to present antigens to T cells. Bone marrow mesenchymal stem cells (MSCs) modulate the differentiation, maturation and function of DCs. In umbilical cord blood an immature MSC population was identified. Remarkably, these immature stem cells modulated DCs in a different way. Marker expression was unchanged during the differentiation of monocytes towards immature DCs (iDCs) when cocultured with cord blood MSC [unrestricted somatic stem cells (USSCs)]. The maturation to mature DCs (mDCs) was enhanced when DCs were co‐cultured with USSC, as evidenced by the up‐regulation of costimulatory molecules. Endocytosis of dextran by iDCs was hampered in the presence of USSCs, which is indicative for the maturation of iDCs. Despite this maturation, the migration of iDCs cocultured with USSCs appeared to be identical to iDCs cultured alone. However, USSCs increased the migration of mDCs towards CCL21 and boosted interleukin‐12 production. So, USSCs mature iDCs, thereby redirecting the antigen‐uptake phenotype towards a mature phenotype. Furthermore, DC maturation by lipopolysaccharide (LPS) or USSCs reflects two distinct pathways because migration was unaffected when iDCs were matured by coculture with USSCs, while it was strongly enhanced in the presence of LPS. DCs are able to discriminate the different MSC subtypes, resulting in diverse differentiation programmes.  相似文献   
14.
The development of a new tuberculosis (TB) vaccine has become one of the main objectives of the scientific community. Protein antigens have been widely explored as subunit TB vaccines, however lipid antigens could be equally important to be used or included in such a vaccine. The aim of this study was to demonstrate the potential of a liposome formulation composed of an extract of lipids from Mycobacterium smegmatis (Ms) as a TB vaccine candidate. We evaluated the immunogenicity of this formulation as well as the cross reactive response against antigens from Mycobacterium tuberculosis (MTb) in BALB/c mice. We determined the anti-liposome IgG response in sera from TB patients and from healthy subjects who displayed a positive (PPD+) or negative (PPD-) tuberculin skin test. A significant increase in anti-liposome IgG (p<0.05) was detected in animals immunized with Bacille Calmette-Guérin (BCG) compared with all groups, and in the group immunized with liposomes from Ms (LMs) compared to animals immunized with either LMs adjuvanted with aluminium (LMs-A) or the negative control group (phosphate buffered saline, PBS) respectively. With respect to the cross reactive response against a cocktail of cell wall antigens (CWA) from MTb, significantly higher IgG levels were observed in animals immunized with BCG and LMs compared to negative controls and either, aluminium-adjuvanted liposomes (LMs-A) or montanide (LMs-M) (p<0.05). Furthermore, the anti-liposome IgG response was significantly superior in sera from pulmonary TB patients compared to PPD+ and PPD- healthy subjects (p<0.001) suggesting the expression of these antigens in vivo during active MTb infection. The results obtained provide some evidence for the potential use of liposomes containing total lipid extracts of Ms as a TB vaccine candidate.  相似文献   
15.
Background  Patients with aneurysmal subarachnoid hemorrhage (SAH) are at risk for circulatory volume depletion, which is a risk factor for delayed cerebral ischemia (DCI). In a prospective observational study we assessed the effectiveness of fluid administration based on regular evaluation of the fluid balance in maintaining normovolemia. Methods  A total of 50 patients with aneurysmal SAH were included and were treated according to a standard protocol aimed at maintaining normovolemia. Fluid intake was adjusted on the basis of the fluid balance, which was calculated at 6-h intervals. Circulating blood volume (CBV) was measured by means of pulse dye densitometry (PDD) on alternating days during the first 2 weeks after SAH. Results  Of the 265 CBV measurements, 138 (52%) were in the normovolemic range of 60–80 ml/kg; 76 (29%) indicated hypovolemia with CBV < 60 ml/kg; and 51 (19%) indicated hypervolemia with CBV > 80 ml/kg. There was no association between CBV and daily fluid balance (regression coefficient β = −0.32; 95% CI: −1.81 to 1.17) or between CBV and a cumulative fluid balance, adjusted for insensible loss through perspiration and respiration (β = 0.20; 95% CI: −0.31 to 0.72). Conclusion  Calculations of fluid balance do not provide adequate information on actual CBV after SAH, as measured by PDD. This raises doubt whether fluid management guided by fluid balances is effective in maintaining normovolemia.  相似文献   
16.
The incidence of geriatric ankle fractures is rising and the potential for complications is high in this population. Little is known about factors associated with increased postoperative complications after surgical fixation of ankle fractures in older-age patients. The purpose of this retrospective cohort study was to assess the epidemiology and risk factors for complications after surgically treated ankle fractures in geriatric patients. All patients who were 65 years or older and had a surgically treated ankle fracture were included. Pilon fractures, patients who were initially treated conservatively or who had less than 1 month of follow-up were excluded. Postoperative complications, demographic-, fracture- and surgical data of 282 patients were recorded from two level 2 trauma centers between 2012 and 2017. A total of 87 (30.9%) patients developed a complication, of which wound related complications were most frequently reported. Superficial and deep wound infections were observed in 27 (9.6%) and 18 (6.4%) patients, respectively. Multivariate regression analysis demonstrated increased age to be an independent predictive variable for the occurrence of postoperative complications (odds ratio 1.04; 95% confidence interval 1.00-1.09), while cast immobilization for more than 2 weeks was a protective factor for the development of wound related complications (odds ratio 0.34; 95% confidence interval 0.17-0.66). In conclusion, the incidence of postoperative complications among geriatric patients after surgical treatment of ankle fractures is high and patients should be informed accordingly.  相似文献   
17.
To establish the outcome of live kidney donors 5 years after donation, we investigated the risk for progressive renal function decline and quality of life (QoL). Data on estimated glomerular filtration rate (eGFR), creatinine, hypertension, QoL and survival were assessed in a prospective cohort of 190 donors, who donated between 2008 and 2010. Data were available for >90%. The mean age predonation was 52.8 ± 11.5 years, 30 donors having pre‐existent hypertension. The mean follow‐up was 5.1 ± 0.9 years. Eight donors had died due to non‐donation‐related causes. After 5 years, the mean eGFR was 60.2 (95% CI 58.7–62.7) ml/min/1.73 m2, with a median serum creatinine of 105.1 (95% CI 102.5–107.8) μmol/l. eGFR decreased to 33.6% and was longitudinally lower among men than women and declining with age (P < 0.001), without any association on QoL. Donors with pre‐existent and new‐onset hypertension demonstrated no progressive decline of renal function overtime compared to nonhypertensives. No donors were found with proteinuria, microalbuminuria or at risk for end‐stage renal disease. After an initial decline postdonation, renal function remained unchanged overtime. Men and ageing seem to affect renal function overtime, while decreased renal function did not affect QoL. These data support further stimulation of living kidney donation programmes as seen from the perspective of donor safety.  相似文献   
18.
19.
Diabetes-related cognitive dysfunction has been recognized for many years in humans, but the pathogenesis of this condition is poorly understood. Evidence from animal studies suggests that altered function of the blood-brain barrier (BBB) could be a potential cause contributing to this disease. This study aimed to investigate whether the permeability of the BBB is affected in the brains of persons with diabetes mellitus (DM). On postmortem prefrontal and temporal cortex of diabetic patients and controls, immunohistochemical stainings were carried out using specific antibodies against three proteins (PAL-E, IgG and albumin), which are considered as markers for the vascular permeability status of the BBB. Rare or no PAL-E staining was found in the capillaries of the prefrontal and temporal cortex parenchyma, in both DM and control materials. IgG and albumin were localized in and directly around blood vessel walls in the prefrontal and temporal cortex. No obvious differences in the staining pattern of IgG and albumin were observed between brain samples of persons with DM and controls. This study suggests that the BBB in diabetic patients is well maintained.  相似文献   
20.
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