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   215篇
  免费   23篇
  国内免费   1篇
  2019年   2篇
  2016年   2篇
  2014年   7篇
  2013年   17篇
  2012年   6篇
  2011年   5篇
  2010年   5篇
  2009年   4篇
  2008年   4篇
  2007年   6篇
  2006年   6篇
  2005年   5篇
  2004年   4篇
  2003年   7篇
  2002年   6篇
  2001年   5篇
  2000年   5篇
  1999年   5篇
  1998年   8篇
  1997年   4篇
  1996年   3篇
  1995年   5篇
  1994年   3篇
  1992年   4篇
  1991年   6篇
  1990年   6篇
  1989年   6篇
  1988年   6篇
  1987年   9篇
  1986年   4篇
  1985年   10篇
  1984年   6篇
  1983年   11篇
  1982年   6篇
  1981年   7篇
  1980年   1篇
  1979年   4篇
  1978年   3篇
  1977年   5篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
  1972年   2篇
  1971年   3篇
  1970年   1篇
  1967年   2篇
  1966年   1篇
  1964年   2篇
  1963年   1篇
  1861年   1篇
排序方式: 共有239条查询结果,搜索用时 15 毫秒
61.
The identification of 5,6-dihydrouridine in normal human urine is reported. Partial purification and isolation of the compound by boronate gel affinity chromatography and reversed-phase high-performance liquid chromatography preceded its characterization as a trimethylsilyl derivative by combined gas chromatography/mass spectrometry. Structure proof is based upon a comparison of mass spectral and chromatographic features of the urinary component to that of an authentic reference sample. Additional data derived from high resolution mass measurements and deuterium isotope-labeling experiments provide confirmation of fragment ion structure. The poor detectability inherent in the HPLC/uv analysis of nucleosides is also discussed.  相似文献   
62.
63.
(1) A simple method is described for the isolation of the lysosomal enzyme, acid alpha-glucosidase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20) from normal human liver. Antibodies raised against the purified enzyme were immobilized by covalent coupling to Sepharose 4B. (2) Acid alpha-glucosidase can be quantitatively removed from normal urine by incubating with an excess of immobilized antibody. With p-nitrophenyl-alpha-glucoside as substrate, acid alpha-glucosidase accounts for 91 +/- 3% of the total alpha-glucosidase activity at pH 4.0 IN Normal urine. (3) In urine from a patient with the infantile form of Pompe's disease ('acid maltase deficiency'), no alpha-glucosidase activity could be removed by the immobilized antibody, in agreement with the fact that acid alpha-glucosidase is absent in these patients. (4) In urine from patients with the late-onset form of Pompe's disease, 46 +/- 11% of the alpha-glucosidase activity at pH 4.0 can be removed by incubation with immobilized antibodies, indicating that residual acid alpha-glucosidase activity is present in urine of these patients. The residual acid alpha-glucosidase activity amounts to about 5% of that in the urine of control persons. (5) If acid alpha-glucosidase is adsorbed to immobilized antibodies, the activity can still be measured with p-nitrophenyl-alpha-glucoside as substrate. The Km for p-nitrophenyl-alpha-glucoside is not significantly changed by adsorbing purified acid alpha-glucosidase to immobilized antibodies. (6) The properties of acid alpha-glucosidase from urine of patients with late-onset Pompe's disease were compared with those of acid alpha-glucosidase from normal urine, both adsorbed to immobilized antiserum. The pH-activity profile of the enzyme from urine of patients with late-onset Pompe's disease can not be distinguished from that of the normal urinary enzyme. The Km for p-nitro-phenyl-alpha-glucoside of the two enzymes is identical, both at pH 4 and 3. The titration curves of the two enzymes with immobilized antibodies are identical.  相似文献   
64.

Background

Viewed through the micro focus of an interpretive lens, medical anthropology remains mystified because interpretivist explanations seriously downplay the given context in which individual health seeking-behaviours occur. This paper draws upon both the interpretivist and political economy perspectives to reflect on the ethno medical practices within the Korean-Australian community in Sydney.

Methods

We draw on research data collected between 1995 and 1997 for an earlier study of the use of biomedical and traditional medicine by Korean-Australians in Sydney. A total of 120 interviews were conducted with a range of participants, including biomedical doctors, traditional health professionals, Korean community leaders and Korean migrants representing a range of socio-economic backgrounds and migration patterns.

Results and Discussion

First, the paper highlights the extent to which the social location of migrants in a host society alters or restructures their initial cultural practices they bring with them. Second, taking hanbang medicine in the Korean-Australian community as an illustrative case, the paper explores the transformation of the dominant biomedicine in Australia as a result of the influx of ethnomedicine in the era of global capitalism and global movement.

Conclusion

In seeking to explain the popularity and supply of alternative health care, it is important to go beyond the culture of each kind of health care itself and to take into consideration the changes occurring at societal, national and global levels as well as consequential individual response to the changes. New social conditions influence the choice of health care methods, including herbal/alternative medicine, health foods and what are often called New Age therapies.  相似文献   
65.
During diving explorations of anchialine cave systems on Abaco Island, Bahamas, we collected five larvae that represent different developmental stages of remipede crustaceans. Based on four early naupliar stages and a post-naupliar larva, it is possible for the first time to reconstruct the postembryonic development of Remipedia some 25 years after their discovery. These specimens begin to fill in some critical gaps in our knowledge of this important group of crustaceans.  相似文献   
66.
High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) were used to analyze the phospholipids and fatty acids of four Arcobacter species (becoming routinely isolated from a wide variety of food sources, especially of animal origin) to provide information for the identification within these species. Phospholipid differences were observed in the HPLC profiles. GC-MS analysis provided a complete fatty acid composition for each arcobacter that after pattern recognition analysis allows taxonomic classification of each species.  相似文献   
67.
A clear association between obesity and heart failure exists and a significant role for leptin, the product of the obese gene, has been suggested. One aspect of myocardial remodeling which characterizes heart failure is a disruption in the balance of extracellular matrix synthesis and degradation. Here we investigated the effects of leptin on matrix metalloproteinase (MMP) activity, tissue inhibitor of metalloproteinase (TIMP) expression, as well as collagen synthesis in HL-1 cardiac muscle cells. Gelatin zymographic analysis of MMP activity in conditioned media showed that leptin enhanced MMP-2 activity in a dose- and time-dependent manner. Leptin is known to stimulate phosphorylation of p38 MAPK in cardiac cells and utilization of the p38 MAPK inhibitor, SB203580, demonstrated that this kinase also plays a role in regulating several extracellular matrix components, such that inhibition of p38 MAPK signaling prevented the leptin-induced increase in MMP-2 activation. We also observed that leptin enhanced collagen synthesis determined by both proline incorporation and picrosirius red staining of conditioned media. Pro-collagen type-I and pro-collagen type-III expression, measured by real-time PCR and Western blotting were also increased by leptin, effects which were again attenuated by SB203580. In summary, these results demonstrate the potential for leptin to play a role in mediating myocardial ECM remodeling and that the p38 MAPK pathway plays an important role in mediating these effects.  相似文献   
68.

Background  

It is a well-known phenomenon that some patients with acute left or right hemisphere stroke show a deviation of the eyes (Prévost's sign) and head to one side. Here we investigated whether both right- and left-sided brain lesions may cause this deviation. Moreover, we studied the relationship between this phenomenon and spatial neglect. In contrast to previous studies, we determined not only the discrete presence or absence of eye deviation with the naked eye through clinical inspection, but actually measured the extent of horizontal eye-in-head and head-on-trunk deviation. In further contrast, measurements were performed early after stroke onset (1.5 days on average).  相似文献   
69.
Using the strictly neutral model as a null hypothesis, we tested for deviations from expected levels of nucleotide polymorphism at the alcohol dehydrogenase locus (Adh-1) within and among four species of pocket gophers (Geomys bursarius major, G. knoxjonesi, G. texensis llanensis, and G. attwateri). The complete protein-encoding region was examined, and 10 unique alleles, representing both electromorphic and cryptic alleles, were used to test hypotheses (e.g., the neutral model) concerning the maintenance of genetic variation. Nineteen variable sites were identified among the 10 alleles examined, including 9 segregating sites occurring in synonymous positions and 10 that were nonsynonymous. Several statistical methods, including those that test for within-species variation as well as those that examine variation within and among species, failed to reject the null hypothesis that variation (both within and between species of Geomys) at the Adh locus is consistent with the neutral theory. However, there was significant heterogeneity in the ratio of polymorphism to divergence across the gene, with polymorphisms clustered in the first half of the coding region and fixed differences clustered in the second half of the gene. Two alternative hypotheses are discussed as possible explanations for this heterogeneity: an old balanced polymorphism in the first half of the gene or a recent selective sweep in the second half of the gene.   相似文献   
70.
Adults of the human parasitic trematode Schistosoma mansoni, which causes hepatosplenic/intestinal complications in humans, synthesize glycoconjugates containing the Lewis x (Lex) Galbeta1-->4(Fucalpha1-- >3)GlcNAcbeta1-->R, but not sialyl Lewis x (sLex), antigen. We now report on our analyses of Lexand sLexexpression in S.haematobium and S.japonicum, which are two other major species of human schistosomes that cause disease, and the possible autoimmunity to these antigens in infected individuals. Antigen expression was evaluated by both ELISA and Western blot analyses of detergent extracts of parasites using monoclonal antibodies. Several high molecular weight glycoproteins in both S. haematobium and S. japonicum contain the Lexantigen, but no sialyl Lexantigen was detected. In addition, sera from humans and rodents infected with S.haematobium and S.japonicum contain antibodies reactive with Lex. These results led us to investigate whether Lexantigens are expressed in other helminths, including the parasitic trematode Fasciola hepatica , the parasitic nematode Dirofilaria immitis (dog heartworm), the ruminant nematode Haemonchus contortus , and the free-living nematode Caenorhabditis elegans . Neither Lexnor sialyl-Lexis detectable in these other helminths. Furthermore, none of the helminths, including schistosomes, express Lea, Leb, Ley, or the H- type 1 antigen. However, several glycoproteins from all helminths analyzed are bound by Lotus tetragonolobus agglutinin , which binds Fucalpha1-->3GlcNAc, and Wisteria floribunda agglutinin, which binds GalNAcbeta1-->4GlcNAc (lacdiNAc or LDN). Thus, schistosomes may be unique among helminths in expressing the Lexantigen, whereas many different helminths may express alpha1,3-fucosylated glycans and the LDN motif.   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