全文获取类型
收费全文 | 6007篇 |
免费 | 299篇 |
国内免费 | 60篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 97篇 |
妇产科学 | 19篇 |
基础医学 | 779篇 |
口腔科学 | 158篇 |
临床医学 | 320篇 |
内科学 | 1592篇 |
皮肤病学 | 155篇 |
神经病学 | 298篇 |
特种医学 | 246篇 |
外科学 | 1022篇 |
综合类 | 30篇 |
预防医学 | 224篇 |
眼科学 | 84篇 |
药学 | 415篇 |
中国医学 | 36篇 |
肿瘤学 | 838篇 |
出版年
2023年 | 32篇 |
2022年 | 59篇 |
2021年 | 135篇 |
2020年 | 75篇 |
2019年 | 104篇 |
2018年 | 109篇 |
2017年 | 122篇 |
2016年 | 150篇 |
2015年 | 148篇 |
2014年 | 179篇 |
2013年 | 242篇 |
2012年 | 388篇 |
2011年 | 403篇 |
2010年 | 231篇 |
2009年 | 218篇 |
2008年 | 366篇 |
2007年 | 417篇 |
2006年 | 425篇 |
2005年 | 450篇 |
2004年 | 420篇 |
2003年 | 412篇 |
2002年 | 395篇 |
2001年 | 62篇 |
2000年 | 53篇 |
1999年 | 86篇 |
1998年 | 95篇 |
1997年 | 73篇 |
1996年 | 88篇 |
1995年 | 53篇 |
1994年 | 38篇 |
1993年 | 42篇 |
1992年 | 29篇 |
1991年 | 31篇 |
1990年 | 25篇 |
1989年 | 36篇 |
1988年 | 25篇 |
1987年 | 15篇 |
1986年 | 14篇 |
1985年 | 16篇 |
1984年 | 19篇 |
1983年 | 12篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1968年 | 3篇 |
排序方式: 共有6366条查询结果,搜索用时 390 毫秒
91.
Healing of two‐wall intra‐bony defects treated with a novel EMD‐liquid—A pre‐clinical study in monkeys
下载免费PDF全文
![点击此处可从《Journal of clinical periodontology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
92.
93.
Junko Daito Yoshinori Harada Ping Dai Yoshihisa Yamaoka Risa Tamagawa-?Mineoka Norito Katoh Tetsuro Takamatsu 《ACTA HISTOCHEMICA ET CYTOCHEMICA》2014,47(2):67-74
Activated platelets form platelet–leukocyte aggregates in the circulation in inflammatory diseases. We investigated whether activated platelets in inflamed skin tissues are phagocytized and removed by neutrophils. To investigate the kinetics of platelets and neutrophils, we immunohistochemically examined the spatiotemporal distribution of them in a murine model of 2,4,6-trinitro-1-chlorobenzene (TNCB)-induced dermatitis by using confocal and structured illumination microscopy. Four hours after elicitation, aggregates of CD41-positive platelets were adhered to CD31-positive endothelial cells within the vessels, and CD62P and PF4, markers of activated platelets, were expressed on platelet aggregates. At 8 hour post-elicitation, fragmented CD41-positive platelets were located both inside and outside vessels. Twenty-four hours after elicitation, the number of Ly-6G-positive neutrophils ingesting fragmented CD41-positive platelets outside vessels was increased, and CD62P and PF4 expression on the phagocytosed platelets was no longer observed. Disc-shaped CD41-positive platelets were not found outside vessels at any time during the experiment. Our data revealed that aggregates of activated platelets inside vessels were ingested and removed by neutrophils in the early stage of TNCB-induced dermatitis, suggesting that the process of removal of activated platelets by neutrophils may play an important role not only in the early phase of skin inflammation but also in other types of acute inflammation. 相似文献
94.
95.
Kitaoka H Kuwahara T Nishida K Morimoto K Kubo T Okawa M Furuno T Doi Y 《Journal of cardiology》2005,45(4):155-159
A 41-year-old man was referred to our hospital for further examination because of abnormal electrocardiography findings at a health-check examination. Transthoracic echocardiography showed left ventricular hypertrophy confined to the most distal portion of the left ventricle, which is a typical feature of apical hypertrophic cardiomyopathy. Ten years later, he was again admitted for the evaluation of chest pain. Echocardiography showed asymmetrical septal hypertrophy in addition to apical hypertrophy. These findings demonstrate morphologic evolution in hypertrophic cardiomyopathy from apical hypertrophy to asymmetrical septal hypertrophy. 相似文献
96.
Ultrastructural study of M cells from colonic lymphoid nodules obtained by colonoscopic biopsy 总被引:4,自引:0,他引:4
Dr. Yoshinori Fujimura MD Masayo Hosobe MD Tsuyoshi Kihara MD 《Digestive diseases and sciences》1992,37(7):1089-1098
The present study was undertaken to investigate ultrastructurally the epithelium covering lymphoid nodules obtained from colonoscopic biopsies of the human colon and rectum. Colonoscopy using the dye spraying contrast, method was performed in nine patients who showed x-ray evidence of lymphonodular hyperplasia. Fifty-two colonoscopical biopsy specimens, of lymphoid nodules were obtained from the ascending, transverse, and descending colon and rectosigmoid region. All specimens were observed by light and electron microscopy. Light microscopy disclosed large lymphoid follicles protruding into the lumen with a dome-type configuration. These extended to the lamina propria of the mucosa and were associated with a massive lymphoid aggregation extending as far as the muscularis mucosa from the submucosa. The epithelium covering these nodules contained a few goblet cells and many lymphocytes. Observation of the elevated surface at the apex by scanning electron microscopy revealed M cells with sparse microvilli in the dome epithelium surrounded by crypts. Transmission electron microscopy disclosed M cells enfolding many immature or mature lymphocytes and plasmocytes. The M cells had cytoplasmic microvilli (so-called microfolds) on their surfaces, well-developed tubulovesicular systems, and vacuoles in the cytoplasm. The basic structure of the M cells as observed by scanning and transmission electron microscopy was the same as that of M cells in the Peyer's patches of humans and mice. The apical surface of the colonic lymphoid follicles in Crohn's disease patients was associated with erosions observed by scanning electron microscopy. The erosions proved to be the naked surface of the dome after removal of the epithelium and many holes from 2.0 to 6.0 m in diameter were observed on the naked surface. At high magnification, lymphocytes were seen projecting from holes (18%) on the naked surface of the dome. These ultrastructural findings indicate that human colonic lymphoid follicles are very similar to those seen in other species. 相似文献
97.
Morinaga S Yamamoto Y Noguchi Y Imada T Rino Y Akaike M Sugimasa Y Takemiya S Takanashi Y 《Hepato-gastroenterology》2003,50(53):1521-1526
BACKGROUND/AIMS: Platelet-derived endothelial cell growth factor (PD-ECGF) is one of the angiogenic factors. The aim of this study was to examine the PD-ECGF concentrations in hepatocellular carcinoma, background liver, and normal liver tissues, and to elucidate their significance on clinicopathological outcomes. METHODOLOGY: The concentration of PD-ECGF in the tissue extract was determined by enzyme-linked immunosorbent assay. RESULTS: PD-ECGF concentrations were significantly higher in hepatocellular carcinoma and background liver tissues compared with normal control liver (p = 0.003, p = 0.001, respectively). PD-ECGF concentrations in hepatocellular carcinoma tissues were positively correlated with intratumoral arteriole densities (r = 0.667, p = 0.009), and were higher in less differentiated carcinomas (p = 0.039). However, tumor PD-ECGF concentration did not affect the patients' disease-free survival rates. Those in the background liver tissues were positively correlated with histological activity index scores (r = 0.650, p = 0.001) and serum alanine aminotransferase levels (r = 0.0452, p = 0.035). CONCLUSIONS: PD-ECGF is up-regulated in hepatocellular carcinoma and the corresponding hepatitis liver. The PD-ECGF concentrations in hepatocellular carcinoma correlated positively with microvessel density, lower differentiation, yet not with patients' prognosis. The concentrations of PD-ECGF in the corresponding hepatitis liver correlated positively with the degree of active hepatitis. 相似文献
98.
Fukuhara K Osugi H Takada N Takemura M Lee S Morimura K Taguchi S Kaneko M Tanaka Y Fujiwara Y Nishizawa S Fukushima S Kinoshita H 《Hepato-gastroenterology》2004,51(59):1515-1518
BACKGROUND/AIMS: Helicobacter pylori infection is known to induce gastritis, oxidative stress, and cyclooxygenase (COX)-2 expression in the gastric mucosa. However, the effect of H. pylori infection on remnant gastritis has not been studied. We investigated whether the severity of remnant gastritis and COX-2 expression were affected by H. pylori infection after distal gastrectomy. METHODOLOGY: The study included 97 patients with gastric cancer who underwent curative distal gastrectomy with lymphadenectomy in our department between May 1999 and April 2001. All patients underwent endoscopic examination 2 weeks before and 12 weeks after surgery. The presence of H. pylori infection was determined by urease activity, hematoxylin-eosin staining, and immunochemical staining. Histologic remnant gastritis was graded based on the degree of neutrophil infiltration using the updated Sydney System. COX-2 expression was estimated immunohistochemically. RESULTS: Both the degree of neutrophil infiltration and the level of COX-2 expression were significantly higher in patients with than without H. pylori (p<0.05). There was a significant correlation between the degree of neutrophil infiltration and the degree of COX-2 expression (p<0.001). CONCLUSIONS: H. pylori eradication may become a treatment for preventing both remnant gastritis as well as remnant gastric carcinoma after distal gastrectomy. 相似文献
99.
Up-regulation of transferrin receptor 1 in chronic hepatitis C: Implication in excess hepatic iron accumulation. 总被引:3,自引:0,他引:3
Hiroyuki Saito Yoshinori Fujimoto Takaaki Ohtake Yasuaki Suzuki Shinobu Sakurai Yayoi Hosoki Katsuya Ikuta Yoshihiro Torimoto Yutaka Kohgo 《Hepatology research》2005,31(4):203-210
BACKGROUND/AIMS:: To clarify the mechanism of excess hepatic iron accumulation in chronic hepatitis C, we investigated the expressions of transferrin receptor 1 and divalent metal transporter 1 in hepatocytes, both of which are involved in cellular iron uptake, in relation to the degree of hepatic iron accumulation and hepatic fibrosis by immunohistochemistrical study. METHODS:: Forty-six hepatic tissues with chronic hepatitis C and five normal hepatic tissues were examined. Chemical detection of hepatic iron accumulation was performed by Perl's Prussian blue stain. The immunohistochemistrical study was performed by avidin-biotin complex method with alkaline phosphatase. RESULTS:: In chronic hepatitis C: (1) Hepatic iron accumulation was significantly increased in relation to the advance of the fibrosis. (2) Divalent metal transporter 1 decreased significantly in relation to the advance of hepatic fibrosis. (3) Transferrin receptor 1 expression was always detected, although not in normal hepatic tissues; there was no relation between expression levels and the degree of hepatic fibrosis. CONCLUSIONS:: These data demonstrated that the transferrin receptor 1 expression was up-regulated irrespective of the degree of hepatic iron accumulation, suggesting that the up-regulation of transferrin receptor 1 might act as one of the key mechanisms implicated in the accumulation of hepatic iron in chronic hepatitis C. 相似文献
100.
Inhibitory effect of ceramide on insulin-induced protein kinase Czeta translocation in rat adipocytes 总被引:2,自引:0,他引:2
Miura A Kajita K Ishizawa M Kanoh Y Kawai Y Natsume Y Sakuma H Yamamoto Y Yasuda K Ishizuka T 《Metabolism: clinical and experimental》2003,52(1):19-24
Ceramide has been confirmed to be a signal mediator of apoptosis that is induced by tumor necrosis factor-alpha (TNF-alpha). It has also been reported that ceramide may induce insulin resistance as well as TNF-alpha. We investigated the effect of ceramide on insulin signaling pathways, such as insulin receptor (IR) beta-subunit, insulin receptor substrate 1 (IRS-1), phosphatidylinositol 3-kinase (PI3K), and protein kinase Czeta (PKCzeta) in rat adipocytes. We examined insulin-stimulated [(3)H]2-deoxyglucose (2-DOG) uptake in rat adipocytes pretreated with N-hexanoylsphingosine (C(6)-ceramide, 10 to 30 micromol/L). Insulin-induced 2-DOG uptake was significantly reduced by C(6)-ceramide pretreatment. We also examined the effect of various concentrations of C(6)-ceramide pretreatment on insulin-induced autophosphorylation of the IR beta-subunit, tyrosine phosphorylation of IRS-1, enzyme activity of PI3K, and membrane-associated PKCzeta immunoreactivity. Pretreatment with C(6)-ceramide significantly reduced autophosphorylation of the IR beta-subunit, tyrosine phosphorylation of IRS-1, and enzyme activity of PI3K. Moreover, membrane-associated PKCzeta immunoreactivity and immunoprecipitable PKCzeta enzyme activity, downstream of PI3K, were significantly suppressed by C(6)-ceramide pretreatment. These results suggest that ceramide may induce insulin resistance via the suppression of IRS-1-PI3K signaling, and subsequent activation of PKCzeta. 相似文献