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   782篇
  免费   38篇
  国内免费   1篇
  821篇
  2024年   1篇
  2023年   6篇
  2022年   4篇
  2021年   8篇
  2020年   5篇
  2019年   3篇
  2018年   5篇
  2017年   13篇
  2016年   15篇
  2015年   23篇
  2014年   28篇
  2013年   64篇
  2012年   43篇
  2011年   47篇
  2010年   34篇
  2009年   31篇
  2008年   46篇
  2007年   39篇
  2006年   48篇
  2005年   39篇
  2004年   49篇
  2003年   52篇
  2002年   38篇
  2001年   11篇
  2000年   9篇
  1999年   9篇
  1998年   12篇
  1997年   16篇
  1996年   9篇
  1995年   11篇
  1994年   7篇
  1993年   7篇
  1992年   9篇
  1991年   6篇
  1990年   7篇
  1989年   11篇
  1987年   3篇
  1986年   4篇
  1985年   3篇
  1984年   2篇
  1983年   5篇
  1982年   3篇
  1981年   6篇
  1980年   7篇
  1979年   12篇
  1978年   2篇
  1977年   3篇
  1976年   3篇
  1975年   3篇
排序方式: 共有821条查询结果,搜索用时 0 毫秒
811.
As part of a larger cross-cultural study of the chemoreceptiveabilities and preferences of Australians and Japanese, thisstudy investigated the differential taste sensitivity of subjectsfrom both cultures. The results indicate that there are no significantdifferences between the abilities of subjects from the two culturesto discriminate small increments (just noticeable differences)in the intensities of the four common tastants: sucrose, sodiumchloride, citric acid and caffeine. Furthermore, the Weber ratiosfound with each tastant were within the range of those reportedin the literature. These findings represent further evidencefor the view that differences in responses of subjects fromdifferent cultures to chemosensory stimuli are restricted topreference behaviour arising from experience rather than fromgenetically-based influences. 3Present address: Faculty of Science and Technology, Universityof Western Sydney, Bourke Street, Richmond, NSW 2753, Australia 4Present address: CSIRO Biometrics Unit, Institute of AnimalProduction and Processing, PO BOx 52 North Ryde NSW 2113, Australia  相似文献   
812.
813.
814.
Patients presenting with functional somatic syndrome (FSS) are common, and the symptoms are persistent and difficult to treat for doctors and costly for society. The aim of this study was to clarify the common pathophysiology of FSS, especially the relationship between hypothalamic-pituitary-adrenal (HPA) axis function and psychological characteristics of patients with FSS. The subjects were 45 patients with FSS and 29 healthy controls. Salivary free cortisol was measured in the morning, and psychological tests examining depression, anxiety and quality of life (QOL) were performed on the same day. In patients with FSS, depressive scores showed a significant negative correlation with salivary free cortisol in the morning, although in healthy controls, cortisol showed a significant positive correlation with depressive scores. In addition, the correlation between other psychological test scores and cortisol secretion in patients with FSS contrasted with that of controls. The relationship between cortisol and depression, anxiety or QOL, suggests that the HPA axis of patients with FSS is dysfunctional and does not function properly when patients with FSS are under stress. This dysfunction may explain the pathology of medically unexplained persistent symptoms of patients with FSS.  相似文献   
815.
816.
Summary Cecum from chickens, 4 wk old, can best be maintained for 24 h in a serum-free organ culture system using Trowell T8 medium agar sheet at 25°C. As determined by light microscopy as well as scanning and transmission electron microscopy, mucosal architecture involving classic ultrastructure of chicken cecal mucosa was preserved. Protein content of cecal explants did not change up to 48 h of culture. DNA content of cecal explants did not change up to 24 h of culture but decreased significantly to two-thirds of control in 48 h of culture. Based on the morphologic and physiologic findings, it became evident that this organ culture system using Trowell T8 medium at 25°C can be successfully used as an in vitro experimental model for as long as 24 h. The organ culture system could be a useful tool, from the structural integrity of ceca observed in this study, in investigating mucosal function and mucosal response to drugs, carcinogens, trophic factors, and pathogens.  相似文献   
817.
Glutathione reductase (GR; EC 1.6.4.2) was purified from spinach roots (rGR) to homogeneity in terms of SDS-PAGE, and its properties were compared with those of the enzyme from spinach leaves (IGR). The two enzymes had similar native molecular (118000) and subunit masses (58000) and immunochemical properties, but different pH optima (ca pH 7.8 for IGR, ca pH 7.2 for rGR) and amino acid compositions. Peptide maps of two GRs showed that they differed from each other. The N-terminal amino acid of the IGR was glycine and that of the rGR was blocked. The partial amino acid sequence of the N-terminal region of the IGR was determined to the 11 th residue and it was found that the sequence of 8 amino acids of the IGR had 100% homology with that of the putative chloroplast GR from Arabidopsis and pea.  相似文献   
818.
819.
The conventional methods of gas liquid chromatography or mass spectrometry failed to be useful for the identification of the biliary 3β, 7α-hydroxychol--en-24-oic acid, a key intermediate of chenodeoxycholic acid biogenesis. It has been preliminarily reported that this acid in human bile was successfully identified by gas chromatography-mass spectrometry, after the methoxylation of its allyl alcohol group. Physical as well as spectral properties of the methoxylation products derived from the acid were reported, compared with those from its 7β-epimer.  相似文献   
820.
Footbaths are considered to provide beneficial thermal therapy for post-stroke patients with spasticity, but their anti-spastic effects have not been investigated comprehensively. The present study aimed to evaluate alterations in motor-neuron excitability using F-wave parameters in post-stroke patients with spastic hemiplegia. Subjects’ legs below the knee joint were immersed in water at 41°C and F-wave recordings were made over the abductor hallucis muscle before, immediately after, and 30 min after thermal treatment. Antidromic stimulation was performed on the tibial nerve at the ankle. Measurements included F-wave amplitude, F-wave/M-response ratio, changes in modified Ashworth scale (MAS), body temperature and surface-skin temperature. The mean values of both F-wave parameters were higher on the affected side before footbath treatment. In post-stroke patients, the mean values of F-wave parameters were significantly reduced after footbath treatment (P < 0.01). The anti-spastic effects of footbath treatment were indicated by decreased F-wave parameters, in parallel with decreases in MAS. Body temperature was significantly increased both immediately after, and 30 min following footbath treatment in both groups, which appeared to play an important role in decreased spasticity. Surface-skin temperature increased immediately after footbath treatment in both groups and returned to baseline 30 min later. These findings demonstrate that the use of footbaths is an effective nonpharmacological anti-spastic treatment that might facilitate stroke rehabilitation.  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