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   1515篇
  免费   60篇
  国内免费   10篇
耳鼻咽喉   5篇
儿科学   16篇
妇产科学   18篇
基础医学   144篇
口腔科学   13篇
临床医学   126篇
内科学   517篇
皮肤病学   27篇
神经病学   128篇
特种医学   94篇
外科学   129篇
综合类   7篇
预防医学   43篇
眼科学   9篇
药学   64篇
中国医学   3篇
肿瘤学   242篇
  2023年   20篇
  2022年   22篇
  2021年   43篇
  2020年   27篇
  2019年   35篇
  2018年   43篇
  2017年   38篇
  2016年   33篇
  2015年   32篇
  2014年   49篇
  2013年   32篇
  2012年   72篇
  2011年   79篇
  2010年   39篇
  2009年   45篇
  2008年   78篇
  2007年   89篇
  2006年   67篇
  2005年   82篇
  2004年   77篇
  2003年   98篇
  2002年   67篇
  2001年   46篇
  2000年   42篇
  1999年   22篇
  1998年   12篇
  1997年   10篇
  1996年   16篇
  1995年   14篇
  1994年   19篇
  1993年   12篇
  1992年   19篇
  1991年   24篇
  1990年   16篇
  1989年   12篇
  1988年   30篇
  1987年   19篇
  1986年   26篇
  1985年   14篇
  1984年   7篇
  1983年   9篇
  1982年   6篇
  1979年   4篇
  1977年   3篇
  1976年   7篇
  1974年   3篇
  1972年   3篇
  1971年   3篇
  1970年   4篇
  1969年   3篇
排序方式: 共有1585条查询结果,搜索用时 46 毫秒
71.
Objectives: The number of patients with insomnia is rapidly increasing as society ages. The influence of insomnia on cognitive, affective, and activities of daily living (ADL) functions has not been fully studied.

Methods: Participants were 142 residents of a local super-aged community who underwent health check-ups provided by the local government. Participants completed cognitive, affective and ADL function tests including the MMSE. We divided participants into two subgroups based on Athens Insomnia Scale (AIS) scores (AIS ≤3 and AIS ≥4) and compared cognitive, affective, and ADL functions by sex and age.

Results: Subjective insomnia (AIS ≥4) was found in 36.2% of participants and was more frequent in females than males. No differences were found in cognitive function between the AIS subgroups. For both sexes, Geriatric Depression Scale scores were significantly higher in the AIS ≥4 subgroup than the AIS ≤3 subgroup. Apathy Scale scores were significantly higher in males in the AIS ≥4 subgroup. Of the AIS subscales, ‘sleepiness during the day’ was significantly higher in females than males (**p < 0.01), especially in those aged ≥75 years (**p < 0.01). This group of older females also showed a significantly lower Trail Making Test scores (*p < 0.05).

Discussion: Insomnia was present in 36.2% of the population in a Japanese super-aged community. Those with insomnia showed more depressive symptoms (both sexes) and males showed more apathy. The most distinct characteristic of females aged ≥75 years was a high frequency of daytime sleepiness, possibly related to a decline in attention and executive function.  相似文献   

72.
Blood levels of inflammatory-related cytokines, including interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, are elevated in patients with alcoholic liver diseases. We investigated the effects of these cytokines and ethanol on the expression of hepatic asialoglycoprotein receptors (AGPRs) in a human hepatoblastoma cell line, HepG2. An [125I]-asialo-orosomucoid binding assay showed significant increases in surface AGPR numbers in HepG2 cells by treatment with IL-1β, IL-6, and TNF-α, to levels which were approximately 130% of the values in untreated control cells. However, the enhanced AGPR numbers induced by treatment with these cytokines were markedly suppressed, to 70%–80% of the number in the untreated cells, by treatment with ethanol. Immunological detection of AGPR with a specific antibody demonstrated that the modulation of surface AGPR numbers was correlated with the cellular expression levels of AGPR. These results suggest that, although IL-1β, IL-6, and TNF-α stimulate the synthesis of hepatic AGPR, ethanol suppresses the expression of AGPR augmented by these cytokines. This leads to an increase in serum asialo-orosomucoid levels caused by the disordered catabolism mediated by AGPR in patients with alcoholic liver disease. (Received Dec. 5, 1997; accepted May 22, 1998)  相似文献   
73.
74.
A 31-year-old man referred to our hospital for treatment of his chronic myeloid leukemia (CML) in the first chronic phase by bone marrow transplantation. We pretreated him with cyclophosphamide and total body irradiation and bone marrow transplantation (BMT) was carried out. On day 31, the engraftment was confirmed and on day 52, acute graft versus host disease (GVHD) was observed. On day 189, he lost consciousness due to cyclosporine A-induced leukoencephalopathy and 375 mg cyclosporine A was changed to 100 mg prednisolone. On day 199, liver dysfunction (AST 410 IU/L, ALT 557 IU/L, gammaGTP 385 IU/L, ALP 363 IU/L, D-Bil 0.3 mg/dl) developed and a liver biopsy was performed. PCR analysis of DNA from the liver biopsy specimen was positive for HHV-6 and immunostaining using anti-HHV-6 and anti-HHV-6b antibodies showed positive staining in the cytosol of hepatocytes. No other viruses were found to induce hepatitis. From these results, he was diagnosed as having HHV-6 hepatitis and it was successfully treated with gancyclovir (GCV) administration.  相似文献   
75.
In many neurodegenerative diseases, the cytopathological hallmark is the presence of ubiquitylated inclusions consisting of insoluble protein aggregates. Lewy bodies in Parkinson's disease and dementia with Lewy bodies disease, glial cell inclusions in multiple system atrophy, and hyaline inclusions in amyotrophic lateral sclerosis (ALS) are representative of these inclusions. The elucidation of the components of these inclusions and the mechanisms underlying inclusion formation is important in uncovering the pathogenesis of these disorders. We hypothesized that Dorfin, a perinuclearly located E3 ubiquitin ligase, participates in the formation of ubiquitylated inclusions in a wide range of neurodegenerative diseases. Here, we report that affinity-purified anti-Dorfin antibody labeled ubiquitylated inclusions of Parkinson's disease, dementia with Lewy bodies disease, multiple system atrophy, and sporadic and familial ALS. A double-immunofluorescence study revealed that Dorfin shows a distribution pattern parallel to that of ubiquitin. Furthermore, by a filter trap assay, we detected that Dorfin is present in the ubiquitylated high-molecular weight structures derived from these diseases. These results suggest that Dorfin plays a crucial role in the formation of ubiquitylated inclusions of alpha-synucleinopathy and ALS. However, because we failed to show the direct binding of alpha-synuclein with Dorfin, future investigations into the binding partner(s) of Dorfin will be needed to deepen our understanding of the pathophysiology of alpha-synucleinopathy and ALS.  相似文献   
76.
77.
Perfluorinated surfactants (PFSs) in Asian freshwater fish species were analyzed to investigate tissue distribution, temporal trends, extent of pollution, and level of PFS exposure through food intake. Freshwater fish species, namely carp, snakehead, and catfish, were collected in Japan, Vietnam, India, Malaysia, and Thailand, and 10?PFSs, including perfluorooctanesulfonate (PFOS) and perfluorooctanoate, were analyzed by liquid chromatography?Ctandem mass spectrometry. PFSs in carp in Tokyo were more concentrated in kidneys (??10 PFSs?=?257?±?95?ng/g wet weight [ww]) and livers (119?±?36?ng/g?ww) than in ovaries (43?±?2?ng/g?ww) and muscles (24?±?17?ng/g?ww). Concentrations of PFOS and its precursor, perfluorooctane sulfonamide, in livers of carp and in waters in Tokyo showed a dramatic decrease during the last decade, probably because of 3?M??s phasing-out of the manufacture of perfluorooctanesulfonyl-fluoride-based products in 2000. In contrast, continuing contamination by long-chain perfluorocarboxylates (PFCAs) with????9 fluorinated carbons was seen in multiple media, suggesting that these compounds continue to be emitted. PFS concentrations in freshwater fish species in tropical Asian countries were generally lower than those in developed countries, such as Japan, e.g., for PFOS in muscle, Vietnam?<?0.05?C0.3?ng/g?ww; India?<?0.05?C0.2?ng/g?ww; Malaysia?<?0.05?C0.2?ng/g?ww; Thailand?<?0.05?ng/g?ww; and Japan (Tokyo)?=?5.1?C22?ng/g?ww. Daily intake of short-chain PFCAs with????8 fluorinated carbons from freshwater fish species in Japan was approximately one order of magnitude lower than that from drinking water, whereas daily intake of PFOS and long-chain PFCAs with????9 fluorinated carbons from freshwater fish species was comparable with or greater than that from drinking water. Because the risk posed by exposure to these compounds through intake of fish species is a matter of concern, we recommend the continued monitoring of PFS levels in Asian developing countries.  相似文献   
78.
79.
PURPOSE: Long-standing ulcerative colitis (UC) predisposes patients to the development of colorectal cancer, but surveillance of colitis-associated cancer by detecting the precancerous lesion dysplasia is often difficult because of its rare occurrence and normal-looking appearance. In sporadic colorectal cancer, aberrant crypt foci (ACF) have been reported by many investigators to be precursor lesions of the adenoma-carcinoma sequence. In the present study, we analyzed the genetic background of ACF to determine whether they could be precursors for dysplasia, and we examined the usefulness of endoscopic examination of ACF as a surrogate marker for surveillance of colitis-associated cancer. EXPERIMENTAL DESIGN: ACF were examined in 28 UC patients (19 patients with UC alone and 9 patients with UC and dysplasia; 2 of those patients with dysplasia also had cancer) using magnifying endoscopy. K-ras, APC, and p53 mutations were analyzed by two-step PCR RFLP, in vitro--synthesized protein assay, and single-strand conformation polymorphism, respectively. Methylation of p16 was analyzed by methylation-specific PCR. RESULTS: ACF that appeared distinct endoscopically and histologically were identified in 27 out of 28 UC patients. They were negative for K-ras, APC, and p53 mutations but were frequently positive for p16 methylation (8 of 11; 73%). In dysplasia, K-ras and APC mutations were negative but p53 mutation (3 of 5; 60%) and p16 methylation (3 of 5; 60%) were positive. There was a significant stepwise increase in the number of ACF from patients with UC alone to patients with dysplasia and to patients with cancer. Univariate and multivariate analyses showed significant correlations between ACF and dysplasia. CONCLUSIONS: We have disclosed an ACF-dysplasia-cancer sequence in colitis-associated carcinogenesis similar to the ACF-adenoma-carcinoma sequence in sporadic colon carcinogenesis. This study suggests the use of ACF instead of dysplasia for the surveillance of colitis cancer and warrants further evaluation of ACF as a surveillance marker in large-scale studies.  相似文献   
80.
BACKGROUND: We studied the clinicopathological characteristics and prognoses of localized stage thyroid diffuse large B-cell lymphoma (DLBCL). PATIENTS AND METHODS: This study included 32 patients with stage I/IIE thyroid DLBCL. Their median age was 66 years, the male/female ratio was 10/22. RESULTS: As to the cellular immunophenotype, CD20 was positive in 31/32, CD5 in 0/32, CD10 in 4/32, CD23 in 1/32, BCL2 in 14/30, and BCL6 in 24/32. Twelve cases showed abnormal karyotypes: two cases with t(8;14)(q24;q32), four cases with 3q27, two cases with 17p11, and four cases with other abnormal karyotypes. As for treatment, eight cases were treated with chemotherapy alone and 24 cases were treated with chemotherapy followed by radiotherapy. Complete response was achieved in 94%. The 5-year progression-free survival was 84% and the 5-year overall survival was 90% with a median follow-up period of 62 months. The germinal center B-cell (GCB) type had a significantly better prognosis than the non-GCB type. CONCLUSION: Localized stage thyroid DLBCL is a disease with a relatively good prognosis. It is, however, a heterogeneous disease with regard to histological type and pathological state. Localized stage thyroid DLBCL has a good prognosis and it is that there are more GCB-type DLBCL lymphomas.  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