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   855篇
  免费   36篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   32篇
妇产科学   7篇
基础医学   93篇
口腔科学   16篇
临床医学   86篇
内科学   297篇
皮肤病学   4篇
神经病学   50篇
特种医学   17篇
外科学   111篇
综合类   4篇
预防医学   16篇
眼科学   14篇
药学   75篇
中国医学   8篇
肿瘤学   62篇
  2022年   13篇
  2021年   13篇
  2020年   10篇
  2019年   7篇
  2018年   15篇
  2016年   17篇
  2015年   12篇
  2014年   24篇
  2013年   26篇
  2012年   48篇
  2011年   50篇
  2010年   19篇
  2009年   23篇
  2008年   36篇
  2007年   35篇
  2006年   45篇
  2005年   45篇
  2004年   44篇
  2003年   60篇
  2002年   37篇
  2001年   19篇
  2000年   21篇
  1999年   20篇
  1998年   8篇
  1997年   13篇
  1994年   5篇
  1993年   5篇
  1992年   10篇
  1991年   7篇
  1990年   5篇
  1989年   8篇
  1988年   13篇
  1987年   17篇
  1986年   12篇
  1985年   14篇
  1984年   11篇
  1983年   6篇
  1982年   7篇
  1981年   10篇
  1980年   5篇
  1979年   5篇
  1977年   5篇
  1975年   5篇
  1972年   9篇
  1971年   5篇
  1970年   6篇
  1969年   14篇
  1968年   8篇
  1967年   10篇
  1966年   4篇
排序方式: 共有893条查询结果,搜索用时 109 毫秒
21.
Graefe's Archive for Clinical and Experimental Ophthalmology - To clarify the prevalence of secondary glaucoma (SG) and its speed of progression in patients with herpes simplex virus...  相似文献   
22.
Abstract: Aim: Hepatitis C virus (HCV) is a major cause of post‐transfusional and sporadic hepatitis, and leads to chronic liver disease. It has been suggested that virus‐specific cytotoxic T lymphocytes are responsible for liver injuries that occur in HCV‐infected patients. However, the detailed characteristics of these lymphocytes have not yet been defined. We have previously reported that CD56+ T lymphocytes, as intermediates between natural killer cell and T lymphocytes, predominantly infiltrated the liver and were increased in patients with chronic hepatitis related to HCV (CH‐C). Material and Methods: We obtained peripheral blood and liver tissues from 32 patients diagnosed as having CH‐C, and 10 other liver disease patients (5 chronic hepatitis related to HBV, 5 alcoholics), and analyzed peripheral blood and liver‐infiltrating lymphocytes using flow cytometric and immunohistochemical techniques. Results: The CD56+ T lymphocyte ratio in the liver of patients with a high histology activity index (HAI) score for chronic hepatitis was higher than that of patients with a low HAI score and patients with other liver diseases. In addition, T lymphocytes from patients with chronic hepatitis with a high HAI score carried mostly γδ‐TCR. There was a correlation between the ratio of CH‐C and serum alanine aminotransferase, category I (periportal inflammation and necrosis), and IV (fibrosis) of the HAI scoring system. The ratio was highest in zone 1 of the hepatic lobules. Conclusion: The correlation between CD56+ T lymphocyte ratios and hepatocellular damage was examined. These findings suggest strongly that liver‐infiltrating CD56+ T lymphocytes play an important pathologic role in hepatocellular injury in CH‐C.  相似文献   
23.
Electron microscopic and virological studies of marmoset liver tissue with acute infection of hepatitis A virus (HAV), especially in the earlier stages of infection, were carried out to characterize the maturation process of HAV. Four marmosets were inoculated intravenously with HAV suspension and sacrificed 1 week, 2 weeks, 3 weeks and 4 weeks after inoculation respectively. Hepatitis A antigen (HAAg) in 10% liver homogenates of marmosets was examined by radioimmunoassay and a large amount of HAAg was detected in the liver homogenate of two marmosets sacrificed 2 weeks and 3 weeks after inoculation respectively. The histodiagnosis of the marmoset sacrificed 2 weeks after HAV inoculation was normal. However, many clusters of virus-like particles about 27 nm in diameter, in both "solid" and "empty" forms were found, mainly in vesicles of Kupffer cells by electron microscopy. In the animal that developed mild hepatitis 3 weeks after inoculation HAV-like particles were found in vesicles of hepatocytes by electron microscopy. By immune electron microscopy using peroxidase-conjugated anti-hepatitis A antibody, HAAg was detected on the particles present within the cytoplasmic vesicles of Kupffer cells or hepatocytes and on the surrounding membrane of the vesicles which contained HAV-like particles.  相似文献   
24.
Maintenance of the cluster of differentiation 4 (CD4) positive lymphocyte count (CD4 count) is important for human immunodeficiency virus (HIV) positive individuals. Although a higher body mass index (BMI) is shown to be associated with a higher CD4 count, BMI itself does not reflect body composition. Therefore, we examined the association of body weight, body composition and the CD4 count, and determined the optimal ranges of CD4 count associated factors in Japanese HIV positive individuals. This cross-sectional study included 338 male patients treated with antiretroviral therapy for ≥12 months. Multiple logistic regression analysis was used to identify factors significantly associated with a CD4 count of ≥500 cells (mm3)−1. The cutoff values of factors for a CD4 ≥ 500 cells (mm3)−1 and cardiovascular disease risk were obtained by receiver operating characteristic curves. Age, body fat percentage (BF%), nadir CD4 count, duration of antiretroviral therapy (ART), years since the HIV-positive diagnosis and cholesterol intake showed significant associations with the CD4 count. The cutoff value of BF% for a CD4 ≥ 500 cells (mm3)−1 and lower cardiovascular disease risk were ≥25.1% and ≤25.5%, respectively. The BF%, but not the BMI, was associated with CD4 count. For the management of HIV positive individuals, 25% appears to be the optimal BF% when considering the balance between CD4 count management and cardiovascular disease risk.  相似文献   
25.
It has recently been discovered that G protein-coupled receptors (GPCR) 41 and 43 are characterized by having the short chain fatty acids acetate and propionate as their ligands. The objective of this study was to investigate the involvement of GPCR41, GPCR43, and their ligands in the process of adipogenesis. We measured the levels of GPCR41 and GPCR43 mRNA in both adipose and other tissues of the mouse. GRP43 mRNA expression was higher in four types of adipose tissue than in other tissues, whereas GPCR41 mRNA was not detected in any adipose tissues. A high level of GPCR43 expression was found in isolated adipocytes, but expression level was very low in stromal-vascular cells. Expression of GPCR43 was up-regulated in adipose tissues of mice fed a high-fat diet compared with those fed a normal-fat diet. GPCR43 mRNA could not be detected in confluent and undifferentiated 3T3-L1 adipocytes; however, the levels rose with time after the initiation of differentiation. GPCR41 expression was not detected in confluent and differentiated adipocytes. Acetate and propionate treatments increased lipids present as multiple droplets in 3T3-L1 adipocytes. Propionate significantly elevated the level of GPCR43 expression during adipose differentiation, with up-regulation of PPAR-gamma2. Small interfering RNA mediated a reduction of GPCR43 mRNA in 3T3-L1 cells and blocked the process of adipocyte differentiation. In addition, both acetate and propionate inhibited isoproterenol-induced lipolysis in a dose-dependent manner. We conclude that acetate and propionate short chain fatty acids may have important physiological roles in adipogenesis through GPCR43, but not through GPCR41.  相似文献   
26.
27.
AIM To clarify the association between aldo-keto reductase family 1 member B10(AKR1B10) expression and hepatocarcinogenesis after hepatitis C virus eradication.METHODS In this study,we enrolled 303 chronic hepatitis C patients who had achieved sustained virological response(SVR) through interferon-based antiviral therapy. Pretreatment AKR1B10 expression in the liver was immunohistochemically assessed and quantified as a percentage of positive staining area by using image-analysis software. A multivariate Cox analysis was used to estimate the hazard ratios(HRs) of AKR1B10 expression for hepatocellular carcinoma(HCC) development after achieving SVR. The cumulative incidences of HCC development were evaluated using Kaplan-Meier analysis and the log-rank test.RESULTS Of the 303 chronic hepatitis C patients,153(50.5%) showed scarce hepatic AKR1B10 expression,quantified as 0%,which was similar to the expression in control normal liver tissues. However,the remaining 150 patients(49.5%) exhibited various degrees of AKR1B10 expression in the liver,with a maximal AKR1B10 expression of 73%. During the median follow-up time of 3.6 years(range 1.0-10.0 years),8/303 patients developed HCC. Multivariate analysis revealed that only high AKR1B10 expression(≥ 8%) was an independent risk factor for HCC development(HR = 15.4,95%CI: 1. 8- 1 3 2. 5,P = 0. 0 1 2). T h e 5- y e a r c u m u l a t i v e incidences of HCC development were 13.7% and 0.5% in patients with high and low AKR1B10 expression,respectively(P 0.001). During the follow-up period after viral eradication,patients expressing high levels of AKR1B10 expressed markedly higher levels of alanine aminotransferase and α-fetoprotein than did patients exhibiting low AKR1B10 expression.CONCLUSION Chronic hepatitis C patients expressing high levels of hepatic AKR1B10 had an increased risk of HCC development even after SVR.  相似文献   
28.
RNA silencing is a natural defense response against viral infection. This phenomenon has been used to interfere with viral infections by exploiting fragments of viral genomes as sources of RNA silencing. Agrobacterium-mediated transient expression of a hairpin RNA derived from the TGBp1 gene of Potato virus X (PVX) induced RNA silencing of the TGBp1 gene and resulted in interference of PVX infection. The interference was induced in the infiltrated leaves but not in the upper non-infiltrated leaves. Transient expression of a CP hairpin RNA also induced interference of PVX. The TGBp1 hairpin RNA showed more efficient interference of PVX infection than the CP hairpin RNA.  相似文献   
29.
Melatonin release from the pineal cells of chicks, pigeons and crows (diurnal birds) in vitro was compared with that from owls ( a nocturnal bird). The pineal cells of diurnal birds secreted large amounts of melatonin during the dark period, whereas oowl pineal cells released virtually no melatonin over 24 h and did not respond to exogenous stimulant agents. Histological examination revealed that the owl pineal gland is very small and has a poor vascular network. These results suggest that the pineal gland of owls may have degenerated and is not involved in the circadian clock mechanism in this species.  相似文献   
30.
Living donor liver transplantation (LDLT) is a treatment for end-stage liver failure, and was developed to overcome the distinct insufficiency of cadaveric donors. Case 1 is a 56-year-old man who had undergone maintenance hemodialysis therapy for 4 years. An LDLT was performed for the treatment of advanced liver cirrhosis and hepatocellular carcinoma. Continuous hemodiafiltration (CHDF) was performed from the 2nd to 5th days after the operation. Case 2 is a 55-year-old man with primary amyloidosis and chronic renal failure. An LDLT was performed for the treatment of severe abdominal distention caused by a large liver volume. Although CHDF was started at the 3rd day after the operation, it was discontinued within 24 hours because of an increased urinary volume. CHDF was required again from the 6th-8th days, after which the blood purification mode was switched to regular intermittent hemodialysis. Meanwhile, no major problems occurred in either case. In conclusion, CHDF was required for about 5 days from the 2nd day after the operation. The application of careful and aggressive blood purification therapy during the perioperative period is a key to successful LDLT in dialysis patients.  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