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排序方式: 共有518条查询结果,搜索用时 15 毫秒
1.
George Wolf DPhil 《Nutrition reviews》2007,65(8):385-388
Retinol-binding protein (RBP) is the transport protein that carries retinol in the circulation from the liver to its target tissues. The existence of a cell-surface receptor on the target cells, which mediates the uptake of retinol from RBP, has been known since 1975. Recently, it was identified as an integral transmem-brane protein named STRA6 that is inducible by retinoic acid in certain cancer cells. The receptor was found to be highly specific for RBP, with high affinity, and to be localized in all tissues known to require retinol for their function, particularly the pigment epithelium of the eye. 相似文献
2.
为筛选大叶紫薇叶中具有降血糖活性的成分,采用3T3-L1细胞葡萄糖消耗模型作为检测手段,对大叶紫薇叶提取物采用HP-20树脂吸附、溶剂萃取、制备薄层分离和制备高效液相分离,导向筛选具有降血糖作用的各分离组分.结果发现,大叶紫薇叶中corosolic acid、熊果酸和总三萜具有降血糖活性. 相似文献
3.
We examined the changes that occur in the adenosine receptor system during diabetes mellitus. Experimental diabetes mellitus
was induced in male Lewis rats with streptozocin (65 mg/kg), and A1 adenosine receptor binding was characterized with [125I]N
6-2-(4-aminophenyl) ethyladenosine. In adipocytes, high-affinity A1 adenosine receptor binding decreased from 1466±228 of protein to 312±123 fmol/mg of protein (p<0.01) following 14 d of untreated diabetes mellitus. Neither the dissociation constant (K
d=1.3±0.2 nM) nor the basal level of adenylate cyclase activity (2.8±1.1 pmol cAMP/mg of protein/min) was altered by diabetes mellitus.
The dose-response curve for the inhibition of adenylate cyclase byN
6-R-phenylisopropyladenosine (R-PIA), however, did show a rightward shift, indicating that diabetic adipocyte membranes were
less sensitive to the effects of adenosine than nondiabetic adipocyte membranes. In contrast, the A1 adenosine receptor-binding characteristics and adenylate cyclase dose-response curve for cerebral cortical tissue were unchanged
by diabetes. These findings suggest that diabetes has tissue-specific effects on the A1 adenosine receptor system. Furthermore, the decreased sensitivity to adenosine potentially worsens the hyperlipidemia associated
with diabetes mellitus. Such alterations in the adenosine receptor system may play a previously undescribed role in the pathophysiology
of diabetes mellitus and may help explain why some organs are severely affected by diabetes, but others are relatively spared.
Understanding these alterations in adenosine receptor function may lead tonovel therapies of this common metabolic disease. 相似文献
4.
Hamilton BS 《Obesity surgery》1996,6(1):7-11
In vitro investigations into adipose cell dynamics have revealed intrinsic characteristics of massively obese individuals' cells that
could contribute to a relatively intractable expanded fat mass. Morbidly corpulent peoples' preadipocytes replicate to a greater
degree than those from lean individuals. Coupled with exaggerated differentiation this enhanced growth would result in a greater
number of fat cells which would increase adipose tissue mass. The relative resistance to de-differentiation that adipocytes
from the massively obese demonstrate would contribute to stability of an increased number of adipocytes further exacerbating
the problem. The increased message of an energy sensing protein, the obese gene product, suggests that the morbidly obese are insensitive to its action. Together these attributes provide a strong
argument for a significant genetic role in the pathogenesis of obesity. 相似文献
5.
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7.
Aim:
Wogonin (5,7-dihydroxy-8-methoxyflavone), a major bioactive compound of the flavonoid family, is commonly extracted from the traditional Chinese medicine Scutellaria baicalensis and possesses antioxidant and anti-inflammatory activities and is assumed to have anti-diabetes function. Indeed, a current study has shown that it can possibly treat metabolic disorders such as those found in db/db mice. However, the underlying molecular mechanism remains largely unclear. The aim of this study was to investigate the impact of wogonin on osteopontin (OPN) expression in adipose tissue from type 1 diabetic mice and in 3T3-L1 adipocytes.Methods:
Type 1 diabetes was induced by streptozotocin (STZ) injection. 3T3-L1 preadipocytes were converted to 3T3-L1 adipocytes through treatment with insulin, dexamethasone, and 3-isobutyl-1-methylxanthine (IBMX). Western blot analysis and RT-PCR were performed to detect protein expression and mRNA levels, respectively.Results:
Wogonin treatment suppressed the increase in serum OPN levels and reduced OPN expression in adipose tissue from STZ-induced type 1 diabetic mice. Administration of wogonin enhanced PPARα expression and activity. Silencing of PPARα diminished the inhibitory effects of wogonin on OPN expression in 3T3-L1 adipocytes. Furthermore, the levels of c-Fos and phosphorylated c-Jun were reduced in wogonin-treated adipose tissue and 3T3-L1 adipocytes. In addition, wogonin treatment dramatically mitigated p38 MAPK phosphorylation. Pharmacological inhibition of p38 MAPK by its specific inhibitor SB203580 increased PPARα activity and decreased OPN expression.Conclusion:
Our results suggest that wogonin downregulated OPN expression in adipocytes through the inhibition of p38 MAPK and the sequential activation of the PPARα pathway. Given the adverse effects of high OPN levels on metabolism, our results provide evidence for the potential administration of wogonin as a treatment for diabetes. 相似文献8.
9.
Tania Romacho Philipp Glosse Isabel Richter Manuela Elsen Marieke H. Schoemaker Eric A. van Tol Jürgen Eckel 《Nutrients》2015,7(2):865-886
Nutritional factors such as casein hydrolysates and long chain polyunsaturated fatty acids have been proposed to exert beneficial metabolic effects. We aimed to investigate how a casein hydrolysate (eCH) and long chain polyunsaturated fatty acids could affect human primary adipocyte function in vitro. Incubation conditions with the different nutritional factors were validated by assessing cell vitality with lactate dehydrogenase (LDH) release and neutral red incorporation. Intracellular triglyceride content was assessed with Oil Red O staining. The effect of eCH, a non-peptidic amino acid mixture (AA), and long-chain polyunsaturated fatty acids (LC-PUFAs) on adiponectin and leptin secretion was determined by enzyme-linked immunosorbent assay (ELISA). Intracellular adiponectin expression and nuclear factor-κB (NF-κB) activation were analyzed by Western blot, while monocyte chemoattractant protein-1 (MCP-1) release was explored by ELISA. The eCH concentration dependently increased adiponectin secretion in human primary adipocytes through its intrinsic peptide bioactivity, since the non-peptidic mixture, AA, could not mimic eCH’s effects on adiponectin secretion. Eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and DHA combined with arachidonic acid (ARA) upregulated adiponectin secretion. However, only DHA and DHA/ARA exerted a potentanti-inflammatory effect reflected by prevention of tumor necrosis factor-α (TNF-α) induced NF-κB activation and MCP-1 secretion in human adipocytes. eCH and DHA alone or in combination with ARA, may hold the key for nutritional programming through their anti-inflammatory action to prevent diseases with low-grade chronic inflammation such as obesity or diabetes. 相似文献
10.
Mariabeatrice Principi Richard Day Stefania Marangi Osvaldo Burattini Vincenzo De Francesco Marcello Ingrosso 《Immunopharmacology and immunotoxicology》2013,35(2):185-195
Tumor necrosis factor alpha (TNFα) in intestinal mucosa plays a key role in the inflammation characterizing Crohn’s disease (CD). Moreover, adhesion molecule syndecan-1 mediates the maintenance of mucosal integrity and supports tissue repair. Therefore, our aim in this study was to correlate simultaneous expression of TNFα and syndecan-1 in patients affected by CD. Biopsies from 10 patients with CD of large bowel and 10 subjects with irritable bowel syndrome (controls) were studied by immunohistochemical detection of both TNFα and syndecan-1 on successive serial sections. Overall labeling index (OLI) was indicated by the percentage of positive stromal (i.e., nonepithelial) cells/1000 counted in randomized fields, whereas selected labeling index (SLI) was represented by the simultaneous evaluation of both molecules in a same single selected field of each specimen. TNFα and syndecan-1 OLI were significantly higher in CD compared with controls, while SLI showed an inverse relationship between the molecules in CD which was not observed in controls. Epithelial syndecan-1 cytoplasmatic staining of superficial epithelium was associated with loss of basolateral staining in the crypts and high stromal TNFα in CD. In conclusion, TNFα and syndecan-1 expression is increased in the intestinal mucosa of patients with CD. However, the expression of the two molecules is inversely related when a single field is considered, these data supporting the possibility of a downregulation exerted by TNFα. 相似文献