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   595篇
  免费   33篇
  国内免费   6篇
耳鼻咽喉   1篇
儿科学   50篇
妇产科学   6篇
基础医学   65篇
口腔科学   8篇
临床医学   44篇
内科学   107篇
皮肤病学   7篇
神经病学   34篇
特种医学   60篇
外科学   86篇
综合类   92篇
预防医学   32篇
眼科学   13篇
药学   16篇
中国医学   1篇
肿瘤学   12篇
  2020年   1篇
  2019年   6篇
  2018年   7篇
  2017年   3篇
  2016年   5篇
  2015年   14篇
  2014年   16篇
  2013年   22篇
  2012年   19篇
  2011年   27篇
  2010年   36篇
  2009年   36篇
  2008年   24篇
  2007年   31篇
  2006年   36篇
  2005年   35篇
  2004年   27篇
  2003年   27篇
  2002年   14篇
  2001年   8篇
  2000年   12篇
  1999年   19篇
  1998年   37篇
  1997年   19篇
  1996年   24篇
  1995年   11篇
  1994年   21篇
  1993年   14篇
  1992年   3篇
  1991年   6篇
  1990年   3篇
  1989年   5篇
  1988年   8篇
  1987年   1篇
  1986年   4篇
  1985年   7篇
  1984年   6篇
  1983年   2篇
  1982年   3篇
  1981年   2篇
  1980年   7篇
  1978年   4篇
  1977年   5篇
  1976年   6篇
  1975年   3篇
  1938年   1篇
  1925年   1篇
  1911年   1篇
  1910年   1篇
  1909年   1篇
排序方式: 共有634条查询结果,搜索用时 0 毫秒
1.
Background. Extensive questioning of patients with a wide variety of skin disorders led to the impression that nocturnal overheating was probably an important factor in the initiation and the perpetuation of many skin disorders. Methods. In order to test the hypothesis, 12 “clean-skinned” subjects (6M/6F) aged 18 to 45 years were monitored electronically every 30 seconds during an 8 hour sleep period (2300 to 0700 hours), sleeping under a standard 10 tog duvet. Results. All the subjects were too hot by 3 to 4°C. All showed changes in their EEG patterns with reduced REM sleep, increased awakenings, and all showed changes in their sleep stage patterns. In addition, they all showed evidence of increased sweating in the “heat-sink” area. Conclusions. The mechanisms where by such changes could be implicated in the precipitation and perpetuation of skin disease are discussed. “Lifestyle” modification as a very effective, noninvasive, therapeutic regime is recommended. Further research along these lines would probably be very valuable and instructive.  相似文献   
2.
An RNA-binding motif (RBM) gene family has been identified on the human Y chromosome that maps to the same deletion interval as the 'azoospermia factor' (AZF). We have identified the homologous gene family (Rbm) on the mouse Y with a view to investigating the proposal that this gene family plays a role in spermatogenesis. At least 25 and probably >50 copies of Rbm are present on the mouse Y chromosome short arm located between Sry and the centromere. As in the human, a role in spermatogenesis is indicated by a germ cell-specific pattern of expression in the testis, but there are distinct differences in the pattern of expression between the two species. Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are female due to a position effect resulting in non-expression of Sry ; sex-reversing such mice with an Sry transgene produces males with a high incidence of abnormal sperm, making this the third deletion interval on the mouse Y that affects some aspect of spermatogenesis. Most of the copies of Rbm map to this deletion interval, and the Yd1males have markedly reduced Rbm expression, suggesting that RBM deficiency may be responsible for, or contribute to, the abnormal sperm development. In man, deletion of the functional copies of RBM is associated with meiotic arrest rather than sperm anomalies; however, the different effects of deletion are consistent with the differences in expression between the two species.   相似文献   
3.
4.
5.
6.
INTRODUCTION: Many factors affect long-term results in kidney transplantation including histologic damage as a independent predictor, such as chronic allograft/nephropathy in protocol biopsies and age-dependent lesions. Histopathologic findings correlate with the incidence of delayed graft function, renal function, and allograft survival, allowing a rather precise prediction of graft outcome. MATERIALS AND METHODS: We analyzed 92 renal thick needle preimplantation and 29 postexplantation biopsies. Biopsies were preserved in 4% formalin and immersed in paraffin. Optimal biopsies contained at least 10 glomeruli and at least 2 cross-sections of arteries. We analyzed tubulitis, intensity of acute tubular necrosis, inflammatory infiltration, glomerulonephritis, arterial hyalinization, arteritis, fibrosis, tubular atrophy, arterial intimal fibrosis, increase of mesangial matrix, and percentage of glomerulosclerosis. During the postoperative course we analyzed patients condition, exigency of postoperative dialysis, urine output, as well as serum concentrations of creatinine, urea, uric acid, and ions. During a 1-year observation period, we analyzed living recipients, graft loss, death with a functioning graft, incidence of nephropathy (CAN), and acute rejection episodes (ARE). RESULTS: We observed a significant correlation between immediate graft function (IGF) and lack of ATN in the pre-0 biopsy. We observed no correlation between renal function and arterial hyalinization and fibrosis, inflammatory infiltration, tubular atrophy. In the postoperative period, we observed a significant correlation between IGF and lack of interstitial fibrosis with significantly lower levels of creatinine, urea, and potassium and higher urine output early after transplantation. IGF and better function of the right kidney was correlated with shorter time to reach a creatinine level of 2 mg%. In the postoperative periods, we also observed a difference between renal function depending on gender. The presence of acute tubular necrosis, arterial fibrosis, lack of inflammatory infiltration in the pre-0 biopsy correlated with worse late renal function. Among explantation biopsies 65.5% showed signs of CAN, and 37.93%, histologic marks of ARE.  相似文献   
7.
BACKGROUND/AIMS: Advanced glycation end-products (AGEs) such as pentosidine play an important role in complications associated with chronic renal failure (CRF) and hemodialysis (HD). This study was undertaken to determine the influence of anthropometric parameters and inflammation on plasma pentosidine concentrations. METHODS: We measured total and free pentosidine in the plasma of 49 patients on chronic HD. Acid hydrolysis of plasma and protein precipitation with trichloroacetic acid was done in the case of total and free pentosidine, respectively. Pentosidine was measured by high performance liquid chromatography (HPLC). C-reactive protein (CRP) was measured by the nephelometric method. RESULTS: A strong negative correlation between dry weight and mean concentration of total pentosidine before and after HD was found (R = -0.47, p < 0.001). This correlation was stronger in males (R = -0.47, p = 0.017) than females (R = -0.34, p = 0.10). Even stronger correlations were noted between body mass index (BMI) and total (R = -0.55, p < 0.001), as well as free (R = -0.39, p = 0.01) pentosidine. Multivariate analysis demonstrated that BMI and time on HD were two independent factors influencing total pentosidine concentrations. CRP did not correlate with pentosidine or BMI. CONCLUSIONS: Lower BMI values are associated with significantly higher plasma pentosidine concentrations in patients on HD. Presumably this relationship is mediated by hypercatabolism observed in these patients. Catabolism produces weight loss and reduces BMI concurrently with the induction of oxidative and carbonyl stresses that stimulate the generation of pentosidine and other harmful AGEs in dialyzed patients.  相似文献   
8.
Phase III noninferiority trial examining efficacy and safety of converting stable renal transplant recipients from twice‐daily tacrolimus to a novel extended‐release once‐daily tacrolimus formulation (LCPT) with a controlled agglomeration technology. Controls maintained tacrolimus twice daily. The primary efficacy endpoint was proportion of patients with efficacy failures (death, graft failure, locally read biopsy‐proven acute rejection [BPAR], or loss to follow‐up) within 12 months. Starting LCPT dose was 30% lower (15% for blacks) than preconversion tacrolimus dose; target trough levels were 4–15 ng/mL. A total of 326 patients were randomized; the mITT population (n = 162 each group) was similar demographically in the two groups. Mean daily dose of LCPT was significantly (p < 0.0001) lower than preconversion tacrolimus dose at each visit; mean trough levels between groups were similar. There were four efficacy failures in each group; safety outcomes were similar between groups. Frequency of premature study drug discontinuation was LCPT: 12% versus tacrolimus twice daily: 5% (p = 0.028). LCPT demonstrated noninferiority to tacrolimus twice daily in efficacy failure rates. LCPT may offer a safe and effective alternative for converting patients to a once‐daily formulation. Compared to currently available tacrolimus formulation, LCPT requires lower doses to achieve target trough levels.  相似文献   
9.
Published literature on fracture in dialysis patients seldom addressed the effect of co‐morbidity and malnutrition. In this study, we reported the incidence and risk factors for fracture in peritoneal dialysis patients. Peritoneal dialysis patients who had fractures between 2006 and 2011 were recruited. Demographic data, details of fracture, Charlson Co‐morbidity Index (CCI) and biochemical parameters were also collected. Non‐fracture controls, matched for age, gender and duration of dialysis, were also recruited at ratio 1:1 for fracture risk analysis. The incidence of fracture was 1 in 37 patient‐years. The commonest site of fracture was neck of femur (n = 16, 55.2%). Twenty‐four patients (82.8%) developed fracture after slip and fall injury. Eight out of 17 self‐ambulatory patients (47.1%) became non‐ambulatory after fracture. Infection was the commonest complication during hospitalization. Univariant analysis demonstrated high CCI (P = 0.001), hypoalbuminaemia (P < 0.001), loss of self autonomy (P = 0.006) and non‐ambulatory state (P = 0.011) significantly associated with increased fracture risk. However, only CCI (odds ratio (OR) 1.373, P = 0.028) and albumin (OR 0.893, P = 0.025) increased fracture risk significantly on multivariant analysis. Bone profile and parathyroid hormone were not significant risk factors. To conclude, fracture associated with adverse outcome in peritoneal dialysis patients. High CCI score and hypoalbuminaemia significantly increase risk of fracture.  相似文献   
10.
INTRODUCTION: Infections are one of the most common complications after organ transplantation. Viral infections such as hepatitis type B (HBV) and C (HCV) or cytomegalovirus (CMV) infections are among the most serious ones. A high frequency of HBV and HCV infections has been recognized in kidney recipients. Viral infections play a special role in graft recipients because of clinical symptoms influencing graft function and recipient survival. Immunosuppressive treatment to decrease immunological reactions after organ transplantation may increase the risk of viral infections. The aim of this study was to evaluate the impact of the presence of HBs antigen and HCV and CMV antibodies on patient and graft survivals. MATERIAL AND METHODS: Two hundred one enrolled kidney transplantation patients (96 women and 105 men) were treated with the same immunosuppressive regimen. Age, sex, and viral state (HBs antigen, anti-HCV and anti-CMV antibodies) were evaluated in every patient. Statistical analysis was performed with the Gompertz model, Kaplan-Meier curves and Cox proportional hazard tests. RESULTS: The presence of HBs antigen was detected in 161 patients (20.4%), HCV antibodies in 61 recipients (30.3%); and CMV antibodies in 12 patients (5.9%). Eighty-seven recipients (43.4%) were seronegative. Average recipient age was 38.5 years. CONCLUSION: Time of graft function was independent of the presence of HBs antigen or HCV or CMV antibodies.  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