首页 | 官方网站   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   2426篇
  免费   96篇
  国内免费   21篇
医药卫生   2543篇
  2023年   6篇
  2022年   14篇
  2021年   37篇
  2020年   21篇
  2019年   21篇
  2018年   33篇
  2017年   29篇
  2016年   62篇
  2015年   52篇
  2014年   71篇
  2013年   68篇
  2012年   128篇
  2011年   142篇
  2010年   78篇
  2009年   82篇
  2008年   152篇
  2007年   158篇
  2006年   150篇
  2005年   192篇
  2004年   178篇
  2003年   193篇
  2002年   197篇
  2001年   29篇
  2000年   17篇
  1999年   25篇
  1998年   43篇
  1997年   46篇
  1996年   34篇
  1995年   27篇
  1994年   35篇
  1993年   22篇
  1992年   19篇
  1991年   16篇
  1990年   9篇
  1989年   14篇
  1988年   16篇
  1987年   6篇
  1986年   10篇
  1985年   9篇
  1984年   22篇
  1983年   11篇
  1982年   10篇
  1981年   14篇
  1980年   7篇
  1978年   8篇
  1977年   4篇
  1975年   3篇
  1974年   3篇
  1972年   4篇
  1971年   5篇
排序方式: 共有2543条查询结果,搜索用时 62 毫秒
51.
Periostin/OSF2 is a ligand for alphavbeta3 and alphavbeta5 integrins and activates the Akt/PKB pathway. Recent reports of periostin/OSF2 gene disrupted mice indicate that periostin/OSF-2 plays an important role in implantation. Quantitative RT-PCR revealed that the expression of periostin/OSF-2 mRNA in rat uteri was reduced to approximately 10% at 12 h after 17beta-estradiol (E2) injection, but was not changed after progesterone (P) injection. RT-PCR revealed the expression of periostin/OSF-2 in human endometrium, cultured human endometrial stromal cells (ESCs), and cultured human endometrial epithelial cells. In ESCs, the expression of periostin/OSF-2 mRNA was reduced to approximately 50% at 6 h after E2 treatment. The amount of periostin/OSF2 mRNA in human endometrium significantly increased during mid-proliferative and early secretory phases of menstrual cycle, and decreased during late-proliferative, mid-secretory and late secretory phases. The expression of periostin/OSF2 mRNA significantly decreased in ESCs decidualized by treatment with E2 and P for 7 and 11 days. By immunohistochemistry, the expression of periostin/OSF-2 was strongly detected in endometrial stromal cells during early proliferative, mid-proliferative and early secretory phases, and was strongly detected in endometrial epithelial cells during late secretory phase. This study demonstrated that the expression of periostin/OSF-2 is regulated by ovarian steroid hormones in rat uterus and human endometrium.  相似文献   
52.
In order to investigate whether the size of thecaudate lobe of the cirrhotic liver is related to thehepatic functional reserve, the morphometric analysis ofthe caudate lobe was preformed retrospectively using computed tomography in 106 consecutivepatients of whom 67 had compensated (group 1), and 39uncompensated (group 2) liver cirrhosis. In 51 patients,hepatic measurements were repeated in follow-up. Age- and gender-matched controls were studied.The size of the caudate lobe and the ratio of thecaudate to right lobe were correlated with liverfunction. The caudate lobe was larger in the studypatients than in the controls, and larger in group 1than in group 2 (P < 0.01). The caudate to right loberatios were also greater in the study patientsespecially in group 1 (P < 0.01). In follow-up, the regression coefficient for the caudate to rightlobe ratio was positive in group 1 and negative in group2 (P < 0.05). Even though the caudate lobe ofpatients with uncompensated liver cirrhosis was larger than that of the controls, patients withcompensated liver cirrhosis had a larger caudate lobeand higher caudate to right lobe ratio compared to thepatients with uncompensated liver cirrhosis. The caudate lobe may have played an importantrole in maintaining proper liver function in thesepatients.  相似文献   
53.
The present study was carried out to investigatethe possibility that lipopolysaccharide deprived fromHelicobacter pylori may alter gastric motility. Toaddress the question, we examined the effect of H. pylori lipopolysaccharide on gastricemptying in conscious rats. Gastric emptying wasevaluated by the phenol red method. Time-course anddose-related effects of intraperitoneal administrationof H. pylori lipopolysaccharide were investigated.Intraperitoneal injection of H. pylorilipopolysaccharide significantly suppressed gastricemptying of a liquid meal in a dose-dependent manner.The inhibitory action of H. pylori lipopolysaccharide wasobserved 2, 4, 8, or 12 hr after the injection. Theseresults suggest for the first time that H. pylorilipopolysaccharide may suppress gastric emptying in along-lasting fashion. It is also suggested that H. pylorimay influence gastric function through its cell wallstructure named lipopolysaccharide.  相似文献   
54.
BACKGROUND AND AIMS: The acute administration of low-dose ethanol was demonstrated to attenuate liver injury elicited by gut ischemia/reperfusion (I/R). Nitric oxide (NO) has been found to be a modulator of adhesive interactions between leukocytes, platelets, and endothelial cells, but there has been much controversy about the effects of ethanol on NO regulation. The objective of this study was to investigate the role of NO in ethanol-reduced hepatic microvascular dysfunction elicited by gut I/R. METHODS: Male Wistar rats were exposed to 30 min of gut ischemia followed by 60 min of reperfusion. Intravital microscopy was used to monitor leukocyte recruitment and non-perfused sinusoids (NPS). Plasma alanine aminotransferase (ALT) activities were measured 6 h after the onset of reperfusion. In another set of experiments, ethanol (10%, 1 g/kg) was administered before ischemia. RESULTS: Gut I/R elicited increases in the number of stationary leukocytes, NPS, and plasma ALT activities; all of which were attenuated by pretreatment with ethanol or an NO donor. Gut I/R caused the apoptosis of hepatocytes, which was prevented by pretreatment with ethanol. Pretreatment with an NO synthase inhibitor diminished the protective effects of ethanol. The administration of ethanol increased plasma nitrite/nitrate levels. CONCLUSION: These results suggest that low-dose ethanol attenuates the gut I/R-induced hepatic microvascular dysfunction and sequential liver injury by increasing sinusoidal NO levels.  相似文献   
55.
To evaluate glycemic control using convenience-oriented biphasic insulin analog compared with intensified insulin therapy, we conducted a 6-month multicentric, open-label, randomized trial in Japanese insulin-naive patients with type 2 diabetes mellitus. A total of 160 adult patients at 19 centers were randomized into two groups: those who received twice-daily injections of biphasic insulin aspart 30 and those on three-times-daily injections of insulin aspart with or without NPH insulin (multiple daily injections). At 6 months, mean HbA(1c) decreased by approximately 2.5% in both groups. Reduction of HbA(1c) on both regimens was better in patients whose prior therapy before starting the study was only diet and exercise (-5.0%) than in patients who were previously taking oral antidiabetic agents (-1.0%). No incidence of major hypoglycemia was observed in either regimen. These results suggest that convenience-oriented insulin therapy using biphasic insulin analog is as useful as intensified insulin therapy with insulin analog for the treatment of type 2 diabetes mellitus over 6 months. Furthermore, early induction of insulin therapy in individuals hitherto using only diet and exercise may provide good glycemic control. This study suggests that convenience-oriented biphasic insulin aspart 30 might be a useful option for the treatment of type 2 diabetes mellitus, especially for insulin-naive patients over 6 months, although it should be changed to another regimen when expected efficacy is not obtained.  相似文献   
56.
57.
Abstract: In the present study, we investigated the role of the spleen in experimental hepatic ischemia/reperfusion in the rat. After a 90-min period of ischemia in the left and middle hepatic lobes, the ischemia was released and the liver was reperfused for up to 24 h. Plasma alanine aminotransferase reached a peak 3 h after the onset of reperfusion, and gradually decreased thereafter. A histological examination revealed evidence of hepatocellular necrosis and degeneration, especially 24 h after the onset of reperfusion. In addition, there was a noticeable accumulation of polymorphonuclear cells in the liver following ischemia/reperfusion. A splenectomy performed just prior to ischemia/reperfusion reduced both biochemical and histological hepatocellular injury. The number of polymorphonuclear cells in the liver following ischemia/reperfusion was significantly reduced in rats subjected to splenectomy, suggesting that the increase in polymorphonuclear cells may contribute to liver injury. The number of mononuclear cells also increased in the marginal zones of the spleen following ischemia/reperfusion, and appeared to be derived from the splenic monocyte/macrophage population, based on immunohistochemical studies. The spleen plays an important role in the pathogenesis of hepatic ischemia/reperfusion injury and the splenic monocyte/macrophage population contributes to liver damage.  相似文献   
58.
BACKGROUND/AIMS: Production of nitric oxide (NO) in the liver is believed to be a critical factor for carbohydrate and energy metabolism in endotoxin shock. The present study focuses on the involvement of NO produced by inducible nitric oxide synthase (iNOS) in glycogen synthesis and energy metabolism stimulated by insulin.METHODS: Primary hepatocytes prepared from wild-type and iNOS knockout (iNOS(-/-)) mice were employed.RESULTS: Incubation of wild-type hepatocytes with a combination of cytokines (interleukin-1beta, tumor necrosis factor-alpha and interferon-gamma) and lipopolysaccharide (cytokines/LPS) inhibited insulin-stimulated glycogen synthesis and adenosine triphosphate (ATP) increase, and decreased the ketone body ratio (KBR) at 8-12 h, concomitant with expression of iNOS protein and NO production. While the glycogen synthesis was suppressed by cytokines/LPS, reduction of the ATP increase and a decrease in KBR by cytokines/LPS were not observed in iNOS(-/-) hepatocytes. Further, N(G)-monomethyl-L-arginine, a NOS inhibitor, reversed the inhibition of ATP increase and decrease in KBR by cytokines/LPS, but not the inhibition of glycogen synthesis. Conversely, addition of S-nitroso-N-acetylpenicillamine, a NO donor, inhibited the insulin-stimulated ATP increase synthesis in iNOS(-/-) hepatocytes, but not the insulin-stimulated glycogen synthesis.CONCLUSIONS: These results demonstrate that NO mediates the suppression of insulin-stimulated energy metabolism, but not glycogen synthesis, in cytokines/LPS-treated hepatocytes.  相似文献   
59.
Intracellular pH is known to increase during agonist-induced platelet activation. In order to elucidate the role of intracellular alkalinization in platelet activation, the effects of NH4Cl, as a tool to induce intracellular alkalinization, on ionomycin-induced platelet activation were investigated. NH4Cl (2.5-10 mM) concentration-dependently induced intracellular alkalinization. Platelet aggregation induced by ionomycin (0.1 microM) was augmented by treatment with NH4Cl (2.5-10 mM). Ionomycin-induced platelet aggregation in the absence of extraplatelet Ca2+, which was markedly attenuated compared to that in the presence of extraplatelet Ca2+, was also augmented by NH4Cl. NH4Cl treatment increased the number of large aggregates after ionomycin stimulation, while it decreased the number of small aggregates. Both transplasmalemmal Ca2+ entry and intracellular Ca2+ release induced by ionomycin were increased by treatment with NH4Cl (10 mM). SKF-96365 (100 microM), an inhibitor of receptor-operated Ca2+ channels, did not affect ionomycin-induced Ca2+ entry but abolished the effect of NH4Cl on Ca2+ entry. Thus, NH4Cl augments receptor-operated Ca2+ channels and intracellular Ca2+ release. These findings suggest that intracellular alkalinization plays a significant role in agonist-induced platelet activation.  相似文献   
60.
We evaluated a rapid urinary antigen detection kit, Binax Now Streptococcus pneumoniae (Binax Inc., USA), which detects S. pneumoniae antigen in urine by immunochromatographic membrane assay, in 379 patients with presumptive pneumonia (total: 454 urine samples). S. pneumoniae antigen was detected in 64 (34%) of 188 patients. In all 64, pneumonia was diagnosed clinically, and there were 11 intense reactivity cases, 27 intermediate cases, and 26 weak cases. We found only two patients with positive sputum cultures for S. pneumoniae among 26 patients with weak reactivity to urinary antigen. The weak urinary antigen reactivity seems to include a false-positive result for S. pneumoniae pneumonia. There were five patients with negative results in whom S. pneumoniae was isolated (false-negative). We took intense and intermediate reactivity to be positive in order to diagnose pneumococcal pneumonia, and the kit showed a sensitivity of 72% and a specificity of 94% in 379 patients. The urinary antigen kit allowed us to diagnose 80% more patients with pneumococcal pneumonia than the use of conventional bacteriological diagnosis alone. There was no significant difference in the initial clinical characteristics, or in the severity of pneumonia among the three groups, according to the color intensity reached using the kit--weak, intermediate, and intense for the reactivity of urinary antigen. The duration of reactivity with S. pneumoniae urinary antigen did not correlate with the clinical characteristics or the severity of pneumonia. We concluded that S. pneumoniae urinary antigen detection kit is a useful adjunct to culturing for determining the etiology of pneumonia.  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-23

京公网安备 11010802026262号