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   460篇
  免费   18篇
  国内免费   1篇
耳鼻咽喉   43篇
儿科学   3篇
妇产科学   3篇
基础医学   38篇
口腔科学   27篇
临床医学   37篇
内科学   67篇
皮肤病学   2篇
神经病学   28篇
特种医学   8篇
外科学   54篇
综合类   2篇
预防医学   27篇
眼科学   3篇
药学   90篇
肿瘤学   47篇
  2023年   5篇
  2022年   7篇
  2021年   9篇
  2020年   5篇
  2019年   3篇
  2018年   12篇
  2017年   3篇
  2016年   5篇
  2015年   8篇
  2014年   11篇
  2013年   13篇
  2012年   22篇
  2011年   32篇
  2010年   13篇
  2009年   9篇
  2008年   38篇
  2007年   23篇
  2006年   19篇
  2005年   24篇
  2004年   16篇
  2003年   19篇
  2002年   15篇
  2001年   23篇
  2000年   17篇
  1999年   8篇
  1998年   3篇
  1997年   7篇
  1996年   5篇
  1995年   2篇
  1994年   5篇
  1993年   4篇
  1992年   6篇
  1991年   10篇
  1990年   8篇
  1989年   4篇
  1988年   8篇
  1987年   11篇
  1986年   6篇
  1984年   6篇
  1983年   3篇
  1980年   2篇
  1979年   3篇
  1978年   7篇
  1977年   2篇
  1976年   2篇
  1973年   3篇
  1971年   2篇
  1967年   1篇
  1966年   3篇
  1922年   2篇
排序方式: 共有479条查询结果,搜索用时 234 毫秒
1.
2.
OBJECTIVE: The objective of this study was to examine the relation of physical performance measures with depressive symptoms in older men. METHOD: A cross-sectional, multivariate comparison of several measures of upper- and lower-extremity performance and their relation with depressive symptoms was performed in 2,856 older Japanese American men, aged 71-93 years, who participated in the fourth examination of the Honolulu Heart Program. Depressive symptoms were measured using an 11-item version of Center for Epidemiologic Studies Depression (CES-D) Scale. A score of at least 9 (from a maximum score of 33) is considered clinically significant. Timed functional performance tests, including walking and repeated chair stands, were used to assess lower-extremity performance; handgrip strength was used as an indicator of upper-extremity performance. RESULTS: Two hundred eighty-three participants (9.9%) had a score of 9 or greater on the 11-question CES-D Scale and were considered to be at high risk for depression. Time to walk 10 feet and time to complete five chair stands were significantly longer in those with depressive symptoms, whereas handgrip strength was significantly lower. Only the association of gait speed (time to walk 10 feet) and depressive symptoms remained significant when all physical performance measures were simultaneously included in a multivariate analysis. CONCLUSION: These results demonstrate physical performance measures, particularly gait speed, may be important potential correlates of depression in community-dwelling older men.  相似文献   
3.
The technical term 'drug dependence' was officially adopted by WHO's Expert Committee on Addiction in 1964. Until this, to describe a state of dependence, terms such as 'poisoning', 'habit', 'ism', and 'addiction' had been used from time to time. Until the 1950's, investigators were mainly focussed on the phenomena of physical dependence. However, once the concept of psychic dependence had been introduced, behavioral and neuropharmacological studies on the modes of drug action that produce psychic dependence were activated and have progressed in the last two decades, and among the points clarified by these studies are the following: 1. The critical drug properties that produce psychic dependence are those of rewarding subjective and reinforcing effects of drugs but these effects are not the properties that produce physical dependence, although the development of physical dependence on particular drugs such as opiates may substantially enhance craving for the drugs. 2. The mesolimbic and mesocortical dopamine systems in the brain and also the N. Accumbens play a primary or at least a partial role in producing the subjective and reinforcing effects of major dependence-producing drugs such as cocaine, opiates, barbiturates, benzodiazepines, and ethanol. 3. Many drugs such as naltrexone, methadone, and some dopamine antagonists and serotonin reuptake inhibitors or antagonists were found to be effective in the pharmacotherapy of the dependence on opiates, cocaine, or ethanol.  相似文献   
4.
The alloreactive immune response is a series of events initiated by the interaction of T cells with allogeneic dendritic cells (DCs), involving alloantigen recognition and costimulatory signals. In this study, we investigated the role of OX40 in alloreactivity in vitro. We first demonstrated that anti-OX40 ligand (anti-OX40L) monoclonal antibody (mAb) could markedly suppress the mixed leucocyte reaction (MLR) of peripheral blood mononuclear cells (PBMC). To further define the contribution of the OX40/OX40L system to the MLR, we set up a co-culture system of CD4+ T cells and allogeneic monocyte-derived dendritic cells (DCs). After 2 days, OX40 expression was induced on CD4+ T cells and this induction was strongly inhibited by the addition of cytotoxic T lymphocyte-associated antigen-4 (CTLA-4)-Fc fusion protein, suggesting that the expression of OX40 during alloreaction is dependent on CD28 signalling. Next we examined the effects of anti-OX40L mAb, CTLA-4-Fc fusion protein and anti-human leucocyte antigen (HLA)-DR mAb on the proliferative response of CD4+ T cells to allogeneic DCs. The proliferation of T cells was almost completely suppressed by anti-OX40L mAb, which was comparable with that of CTLA-4-Fc. Measurement of interleukin-2 (IL-2) production in the culture supernatants showed that suppression of a proliferative response was at least in part ascribed to reduced IL-2 production. Furthermore, purified OX40L- allogeneic DCs could induce considerable proliferation of CD4+ T cells, which was suppressed by anti-OX40L mAb. These results suggest that the OX40/OX40L system is crucial for induction of the allogeneic T-cell response and the OX40/OX40L system is subsequent to and dependent on CD28 signalling, but is crucial for the end outcome of the human alloreactive T-cell response.  相似文献   
5.
It is well known that physical exercise can reduce coronary risk factors. But how an aerobic exercise modifies coronary risk factors in relation to severity and physical fitness is still controversial. Fifty-four middle-aged women (mean age, 55 years) completed a 6-month on-site and home-based anaerobic threshold-level exercise program. The changes in coronary risk factor profiles were observed during the pre-intervention and intervention periods. Before the intervention (during control period), most coronary risk factors showed a rather unfavorable trend. After the program, their mean body weight decreased from 56.7 to 55.7 kg (p>0.05) and the proportion of body fat from 30.9 to 27.9% (p>0.05) without any reduction in lean body mass. Systolic blood pressure (SBP) decreased from 129.0 to 125.0 mm Hg (p>0.05) and diastolic blood pressure from 79.5 to 76.6 mm Hg (p>0.05). Fasting plasma glucose (FPG) declined from 109.6 to 103.4 mg/dl (p>0.05). Changes in SBP and FPG were most remarkable in their respective worst tertile. Serum lipids improved only modestly. Maximum oxygen uptake increased from 23.6 to 26.1 ml/kg/min (p>0.01). However, no significant correlations were found between changes in coronary risk factors and those in physical fitness. We conclude that the 6-month aerobic exercise program would modify women’s coronary risk factors depending on their initial values, probably independently of the changes in physical fitness.  相似文献   
6.
Summary The erythrocyte band 3 (EPB3) variant, band 3 Memphis (EPB3*Memphis), was detected by immunoblotting with a monoclonal antibody to the 41 kDa cytoplasmic N-terminal domain of band 3 without protease treatment of erythrocytes. EPB3*Memphis was also detected by immunoblotting from 3-month-old bloodstains subjected to -chymotrypsin treatment. A population genetic study using this method indicated that the EPB3 variant would be useful for forensic work in Japan, since the frequency of this variant in Japanese (Wakayama prefecture) is relatively high (0.159).  相似文献   
7.
A 29-year-old male with Down's syndrome presented with severe headache and vomiting. Computed tomography demonstrated subarachnoid hemorrhage. Left carotid angiography showed severe stenosis of the middle cerebral artery 2 cm distal to its origin, as well as abnormal hyper-vascularization near the stenosis site similar to that seen in moyamoya disease. Right carotid angiography showed no abnormalities. However, slight stenosis of the distal part of the bilateral vertebral arteries was noted. There was no aneurysm. We judged that the subarachnoid hemorrhage had been caused by rupture of the moyamoya-like vessel. Some patients with Down's syndrome have anatomical vascular abnormality and vascular fragility. The cerebral vascular abnormality found in this case may be part of the systemic vascular abnormalities associated with Down's syndrome. The vascular changes in some adult patients with Down's syndrome may be a sign of premature aging, and long-term studies with periodic vascular examination of patients with Down's syndrome need to be performed.  相似文献   
8.
Since the first treatment of acoustic neurinoma using the γ-knife by Leksell, a series of cases have been reported with good control rates. However, the most frequent complication is delayed hearing loss which occurs in more than 50% of patients. The purpose of this study was to define a safe dose by analyzing the radiosurgical dose-response relationship and histological effects on the normal cochlear nerve in rabbit. The rabbits had computed tomography (CT)-guided stereotactic radiosurgery on their cochlear nerves in the internal auditory canal with a 4 mm collimator focusing of a γ-unit. Maximum doses of 10, 20, 30, 40, 60, 80, 100, 200 and 500 Gy were administered. After the radiosurgery, auditory brain stem responses (ABR) and the behavior of the rabbits were evaluated periodically. At the conclusion, histological investigations were performed. No physiological or histological findings were observed from doses of 30 Gy or below during the 12 month period after the radiosurgery. A dose of 100 Gy caused a severe ABR threshold elevation, vestibular dysfunction and facial palsy. Necrosis and demyelination of nerves were observed pathologically. In this study, we determined that the safe dose to the normal cochlear nerve during radiosurgery was under 40 Gy in rabbits, and complications seemed to vary due to individual differences in radiation tolerance.  相似文献   
9.
10.
Tobacco smoking is a significant risk factor for periodontal diseases. Nicotine, one of the most studied constituents in cigarette smoke, is thought to modify immune responses. Dendritic cells (DCs), which are key mediators between innate and adaptive immunity, stimulate naive T cells to differentiate to effector T‐cell subsets that may be actively involved in the immunopathogenesis of periodontal diseases. In this study, we evaluated the effects of nicotine and lipopolysaccharide (LPS) from Porphyromonas gingivalis, alone and in combination, on the functions of human monocyte‐derived DCs to elucidate the mechanism of tissue destruction of smoking‐associated periodontal diseases. P. gingivalis LPS‐stimulated DCs differentiated with nicotine (NiDCs) induced lower T‐cell proliferation and human leukocyte antigen (HLA)‐DR expression, but elevated expression of programmed cell death ligand 1. Additionally, NiDCs impaired interferon‐γ production but maintained interleukin (IL)‐5 and IL‐10 production in co‐cultured T cells. Furthermore, NiDCs produced lower levels of proinflammatory cytokines compared with DCs differentiated in the absence of nicotine. Interestingly, NiDCs preferentially produced the T helper 2 (Th2)‐type chemokines macrophage chemotactic protein‐1 and macrophage‐derived chemokine. These results suggest that the presence of nicotine during differentiation of DCs modulates the immunoregulatory functions of P. gingivalis LPS‐stimulated DCs.  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