全文获取类型
收费全文 | 5534篇 |
免费 | 481篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 101篇 |
妇产科学 | 145篇 |
基础医学 | 977篇 |
口腔科学 | 104篇 |
临床医学 | 551篇 |
内科学 | 1181篇 |
皮肤病学 | 185篇 |
神经病学 | 793篇 |
特种医学 | 201篇 |
外科学 | 506篇 |
综合类 | 45篇 |
一般理论 | 4篇 |
预防医学 | 345篇 |
眼科学 | 138篇 |
药学 | 302篇 |
中国医学 | 8篇 |
肿瘤学 | 409篇 |
出版年
2024年 | 15篇 |
2023年 | 97篇 |
2022年 | 135篇 |
2021年 | 241篇 |
2020年 | 169篇 |
2019年 | 218篇 |
2018年 | 247篇 |
2017年 | 195篇 |
2016年 | 256篇 |
2015年 | 257篇 |
2014年 | 287篇 |
2013年 | 340篇 |
2012年 | 514篇 |
2011年 | 491篇 |
2010年 | 247篇 |
2009年 | 226篇 |
2008年 | 330篇 |
2007年 | 269篇 |
2006年 | 279篇 |
2005年 | 260篇 |
2004年 | 177篇 |
2003年 | 194篇 |
2002年 | 149篇 |
2001年 | 40篇 |
2000年 | 30篇 |
1999年 | 33篇 |
1998年 | 35篇 |
1997年 | 28篇 |
1996年 | 18篇 |
1995年 | 22篇 |
1994年 | 19篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 11篇 |
1987年 | 11篇 |
1986年 | 12篇 |
1985年 | 14篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1979年 | 6篇 |
1977年 | 14篇 |
1976年 | 10篇 |
1975年 | 12篇 |
1974年 | 5篇 |
1972年 | 9篇 |
1970年 | 6篇 |
1926年 | 5篇 |
排序方式: 共有6028条查询结果,搜索用时 15 毫秒
11.
Analysis of epidermal growth factor receptor and activated epidermal growth factor receptor expression in pituitary adenomas and carcinomas. 总被引:2,自引:0,他引:2
Onder Onguru Bernd W Scheithauer Kalman Kovacs Sergio Vidal Long Jin Shuya Zhang Katharina H Ruebel Ricardo V Lloyd 《Modern pathology》2004,17(7):772-780
Epidermal growth factor receptor plays an important role in the pathogenesis of many malignancies. Various growth factors, including epidermal growth factor receptor, have been shown to influence pituitary tumor growth and differentiation. To analyze the role of epidermal growth factor receptor in pituitary tumor development, we examined normal pituitaries (n=8), pituitary adenomas (n=158), and pituitary carcinomas (n=7) for expression of epidermal growth factor receptor protein and messenger RNA using tissue microarrays and RT-PCR. We also examined (a) the expression of phospho-epidermal growth factor receptor, the activated form of epidermal growth factor receptor, in pituitary tumors and normal pituitaries by immunohistochemistry and (b) the effects on epidermal growth factor receptor expression of treating pituitary cells (HP75 cell line) with epidermal growth factor. Epidermal growth factor receptor and the phosphorylated variant expression were present in normal pituitary cells. Epidermal growth factor receptor messenger RNA was also detected in normal pituitaries, pituitary adenomas, and carcinomas by in situ hybridization and RT-PCR. Most pituitary adenomas showed expression of epidermal growth factor receptor and the phosphorylated variant. Nonfunctional adenomas showed higher levels of expression of epidermal growth factor receptor (76 vs 34%) and of phospho-epidermal growth factor receptor (26 vs 8%) as compared to functional adenomas. Five of seven pituitary carcinomas showed strong expression of both epidermal growth factor receptor and phospho-epidermal growth factor receptor. When a human pituitary cell line (HP75) was cultured in the presence of epidermal growth factor receptor, there was an increase in the levels of both epidermal growth factor receptor and phospho-epidermal growth factor receptor after 5 h of treatment, thus confirming that epidermal growth factor receptor signaling was active in pituitary tumors. These results indicate that activated epidermal growth factor receptor is expressed in pituitary adenomas and carcinomas. Higher levels in pituitary carcinomas suggest a role in pituitary tumor progression. 相似文献
12.
Christian Rüegg Martin Hersberger Barbara Wusk Katharina Rentsch Gerd A Kullak-Ublick Arnold von Eckardstein Friedrich E Maly 《Clinical chemistry and laboratory medicine》2004,42(5):494-498
Crohn's disease is a complex disorder, with multiple genetic traits. A frameshift mutation (Leu1007fsinsC) and two missense mutations (Gly908Arg and Arg702Trp) in the NOD2/CARD15 gene are strongly associated with susceptibility to Crohn's disease. The presence of one of these risk alleles confers a 2- to 4-fold increase in the risk of developing Crohn's disease, and the presence of two mutant alleles increases the risk over 20-fold. To facilitate the analysis of these polymorphisms, we developed three LightCycler assays to detect the missense mutations Arg702Trp and Gly908Arg and the frameshift mutation Leu100fsinsC in the NOD2/ CARD15 gene. All three assays can be run simultaneously on one LightCycler using identical cycling parameters. Analysis of 53 DNAs from Crohn's patients helped to identify carriers at allele frequencies similar to other Caucasian populations. The sequencing of such DNAs confirmed the accuracy of the assays. In conclusion, we present three rapid and robust assays to detect the Arg702Trp, the Gly908Arg and the Leu1007fsinsC ins mutations in the NOD2/CARD15 gene [corrected] 相似文献
13.
J. Menzel O. Schober P. Reimer W. Domschke 《European journal of nuclear medicine and molecular imaging》1997,24(6):635-641
In patients with liver cirrhosis a transjugularly placed intrahepatic portocaval shunt (TIPS) is a non-surgical portosystemic device which aims to reduce portal venons pressure. In comparison with Doppler sonography, we evaluated in 28 patients the diagnostic impact of liver perfusion scintigraphy (with technetium-99m diethylene triamine penta-acetic acid) in the assessment of changes in the hepatic blood flow after TIPS shunting. The arterial and portal contributions to hepatic flow were calculated from the areas under the biphasic timeactivity curve. In the course of TIPS shunting, patency is threatened by reocclusion. Angiography is the gold standard for TIPS shunt reassessment. However, there is a need for a less invasive diagnostic procedure, such as scintigraphy or Doppler sonography, for the early detection of shunt insufficiency. Scintigraphy demonstrated that prior to TIPS shunting the portal venons contribution to hepatic perfusion was reduced to 29.2%, this reduction being due to portal hypertension. After TIPS placement a significant increase in portal venous perfusion was observed (38.2%;P<0.02). TIPS shunt occlusion was identified in patients by a significant reduction in the scintigraphically measured portal venons contribution to hepatic blood flow. Hepatic perfusion scintigraphy appears to be a valuable method to determine the immediate effect of TIPS on hepatic blood flow. Post-TIPS follow-up studies of hepatic haemodynamics by liver perfusion scintigraphy appear able to contribute to the detection of TIPS shunt occlusion before the clinical consequences of this complication have become apparent. 相似文献
14.
Dr. Carsten Herskind Katharina Fleckenstein Jens Lohr Chuan-Yuan Li Frederik Wenz Frank Lohr 《Strahlentherapie und Onkologie》2004,180(4):187-193
BACKGROUND: During the last 2 decades, cytokines such as interferons (IFN) have been used to modulate tumor response in radiotherapy. Initially, the focus was on antiviral and radiosensitizing effects of interferons but increasingly, the function of interferons and interleukins (IL) within the immune response to tumor cells is becoming important. METHOD: The cellular immune response toward tumor cells is reviewed. The role of cytokines in antigen presentation and activation of effector cells and their interactions with radiation are described. Preclinical strategies of the antitumor action of cytokines are presented and discussed based on the induction of IFN-gamma by IL-12. RESULTS: Recent advances in immunology have demonstrated the importance of local interactions between antigen-presenting cells (APC) and effector cells such as natural killer (NK) cells and T-lymphocytes for an effective immune reaction against tumors. Interferons stimulate such interactions, while IL-2 plays a central role in the activation of NK cells and T-lymphocytes. The interactions between APC and effector cells are suppressed by many tumors but can be stimulated by irradiation. Since systemic application of interferons is quite toxic, present strategies aim at local expression, e. g., the induction of IFN-gamma expression in Th1 cells by IL-12. CONCLUSION: The improved understanding of immunologic mechanisms has emphasized the role of the cytokine network in the interaction between tumor cells and effector cells such as NK cells and T-lymphocytes. This opens new possibilities for the application of cytokines as biological response modifiers, which may eventually help widening the therapeutic window in radiotherapy. 相似文献
15.
Thomas Rosemann Michel Wensing Katharina Joest Matthias Backenstrass Cornelia Mahler Joachim Szecsenyi 《BMC musculoskeletal disorders》2006,7(1):48-9
Background
Osteoarthritis (OA) is highly prevalent and has substantial impact on quality of life as well as on healthcare costs. The general practitioner (GP) often is the first care provider for patients with this chronic disease. The aim of this study was to identify health care needs of patients with OA and to reveal possible obstacles for improvements in primary care management of OA patients. 相似文献16.
Shahrokh Taghavi Katharina Krenn Peter Jaksch Walter Klepetko Seyedhossein Aharinejad 《American journal of transplantation》2005,5(6):1548-1552
Bronchiolitis obliterans (BO) is a survival-limiting factor in lung transplantation. There are no common BO markers in use. Since BO is associated with extracellular matrix remodeling, we asked whether matrix metalloproteases (MMPs) and their tissue inhibitors (TIMPs) could serve as BO markers. In 72 lung transplant patients (34 BO syndrome (BOS) 0, 15 BOS 0-p, and 23 BOS 1) serum and broncho-alveolar lavage (BAL) MMP and TIMP levels were examined by ELISA. The BAL cell counts were additionally analyzed. The serum MMP-2, MMP-8, MMP-9 and TIMP-2 levels were not different in all groups. In contrast, the BAL MMP-8, -9 and TIMP-1 levels were significantly elevated in BOS 0-p (p = 0.003; p = 0.007; p = 0.0003, respectively) and BOS 1 (p = 0.003; p = 0.001; p = 0.0004, respectively) as compared to BOS 0 patients. The BAL MMP-8, -9 and TIMP-1 levels were significant predictors of BOS 0-p (p = 0.01; p = 0.01; p = 0.01, respectively) and BOS-1 (p = 0.007; p = 0.01; p = 0.006, respectively) in receiver operating characteristic analysis. Except for BAL macrophages that were significantly decreased in BOS 0-p versus BOS 0 patients; other cell counts were not different between the groups. BAL MMP-8, -9 and TIMP-1 might be useful markers to detect BO in lung transplant patients. 相似文献
17.
Role of endogenous nitric oxide in the control of exocrine and endocrine pancreatic secretion in humans. 总被引:4,自引:0,他引:4 下载免费PDF全文
BACKGROUND: Nitric oxide (NO) is an unstable vasodilator formed by NO synthetase (NOS) from L-arginine (L-Arg) in various cells but its role in the control of pancreatic secretion in humans has not been examined. AIMS: This study was designed to determine the role of endogenous NO in the control of exocrine and endocrine pancreas using NOS inhibitor, NG-monomethyl-L-Arg (L-NMMA). METHODS: Pancreatic secretion was stimulated by intravenous infusion of secretin (80 pmol/kg/h) plus caerulein (50 pmol/kg/h) and duodenal content was aspirated by gastroduodenal tube. Two series of tests with secretagogue infusion were performed, one, with addition of graded doses of L-NMMA and, another, with addition of a constant dose of L-Arg alone followed by L-NMMA alone and finally by a combination of L-Arg and L-NMMA. RESULTS: Addition of L-NMMA in graded doses (2-8 mumol/kg/h) reduced dose dependently the secretin-caerulein stimulated pancreatic enzyme secretion without alterations in the volume flow and bicarbonate outputs. The addition of L-Arg to L-NMMA reversed the inhibitory action of L-NMMA on protein enzyme response to secretin-caerulein in these subjects. Secretin-caerulein infusion caused significant increase in plasma insulin and pancreatic polypeptide levels but without changes in plasma glucagon or somatostatin levels. L-NMMA alone resulted in a significant fall in plasma insulin and pancreatic polypeptide levels, while L-Arg added to pancreatic secretagogue infusion caused a significant increase of plasma insulin and pancreatic polypeptide levels above those attained with secretagogues alone. After the addition of L-Arg to L-NMMA, both plasma insulin and pancreatic polypeptide levels rose significantly above the levels observed with L-NMMA plus secretin-CCK stimulation. CONCLUSION: This study provides evidence that the suppression of NOS reduces pancreatic enzyme secretion and the plasma insulin and pancreatic polypeptide levels suggesting that endogenous NO affects both exocrine and endocrine pancreatic secretion in humans. 相似文献
18.
Eric Goodyer Frank Müller Katharina Licht Markus Hess 《European archives of oto-rhino-laryngology》2007,264(6):631-635
The shear modulus of the vocal fold is an essential parameter required to enhance our understanding of how the vocal fold
operates, to develop mathematical models of phonatation, and to provide benchmarks to quantify the effectiveness of surgical
procedures. The authors announced the successful deployment of an instrument to measure vocal fold elasticity in vivo last
year, and now present the data taken from eight patients in vivo. The shear modulus was measured at the mid-membranous point,
in a transverse direction with respect to the axis drawn between the anterior commissure and vocal process. The range of mean
shear modulus results is 701–2,225 Pa, with a mean value of 1,371 Pa. 相似文献
19.
Horst Claassen Frank Hornberger Katharina Scholz-Ahrens Michael Schünke Jürgen Schrezenmeir Bodo Kurz 《Annals of anatomy》2002,184(2):141-148
Clinical observations have suggested that estrogens are involved in the pathogenesis of postmenopausal osteoarthritis (OA). However, positive and negative associations between the incidence of OA and serum estrogen concentrations have been reported. In contrast to this, osteoporosis is regarded as a disease with a strong estrogen-dependent component. Moreover, there is an interaction between estrogen and calcium deficiency: calcium supplementation potentiates the effect of estrogen therapy. The present study was designed to investigate how estrogen deficiency affects the articular cartilage depending on calcium supply. The distribution of different types of glycosaminoglycans and collagens can be used as an indicator for extracellular matrix changes induced by estrogen deficiency. Different levels of dietary calcium were therefore fed to intact and ovariectomized G?ttingen miniature pigs for one year before articular cartilage was harvested. The histochemical staining for heavy sulfated glycosaminoglycans in the extracellular matrix of ovariectomized miniature pigs, especially of those fed with a low calcium diet, was stronger in comparison to intact animals. In intact animals type II-collagen was immunodetected in all zones of unmineralized and mineralized articular cartilage, while immunostaining for this protein was negative to weak in the deep radiated fiber zone of ovariectomized minipigs. These results suggest that the synthesis of heavy sulfated glycosaminoglycans and immunohistochemically detectable type II-collagen is possibly influenced by estrogen deficiency. In conclusion, under estrogen deficiency, the extracellular matrix of articular cartilage underwent similar changes to those observed in physiologically aging cartilage where keratan sulfate is increased as a heavy sulfated glycosaminoglycan. 相似文献
20.