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   3247篇
  免费   162篇
  国内免费   76篇
耳鼻咽喉   37篇
儿科学   116篇
妇产科学   46篇
基础医学   421篇
口腔科学   49篇
临床医学   257篇
内科学   568篇
皮肤病学   55篇
神经病学   292篇
特种医学   98篇
外科学   475篇
综合类   20篇
预防医学   506篇
眼科学   98篇
药学   198篇
中国医学   9篇
肿瘤学   240篇
  2023年   19篇
  2022年   22篇
  2021年   41篇
  2020年   30篇
  2019年   48篇
  2018年   44篇
  2017年   33篇
  2016年   51篇
  2015年   46篇
  2014年   64篇
  2013年   96篇
  2012年   156篇
  2011年   175篇
  2010年   84篇
  2009年   78篇
  2008年   183篇
  2007年   206篇
  2006年   179篇
  2005年   182篇
  2004年   131篇
  2003年   124篇
  2002年   125篇
  2001年   109篇
  2000年   112篇
  1999年   88篇
  1998年   36篇
  1997年   31篇
  1996年   26篇
  1995年   32篇
  1994年   24篇
  1993年   20篇
  1992年   62篇
  1991年   50篇
  1990年   79篇
  1989年   65篇
  1988年   52篇
  1987年   46篇
  1986年   71篇
  1985年   42篇
  1984年   30篇
  1983年   36篇
  1979年   34篇
  1978年   22篇
  1975年   19篇
  1974年   20篇
  1973年   19篇
  1972年   20篇
  1970年   17篇
  1969年   27篇
  1967年   18篇
排序方式: 共有3485条查询结果,搜索用时 31 毫秒
71.
The qualitative control of the roentgenographic findings was performed independently by the assessment of five x-ray specialists on 40 two-directional lumbosacral roentgenograms. The findings were based on questioners including all details and a table of the internationally used "Radiological Diagnosis". In earlier publications the anatomical and structural changes were considered the risk factors of the waist. (Osteoporosis, changes in the position of the vertebral body, change in the shape of the spine, restriction of the intervertebral cleft and deformation of the small articulations). The views of the research workers were compared by means of statistical analysis. Compared with other authors the methods of these findings are in agreement with the international norms. These findings drew attention to the necessity of an objective assessment of the subjective findings.  相似文献   
72.
Kiss J  Gödry G 《Magyar sebészet》2000,53(5):220-222
The authors of this study report an extraordinary case which is rather rare even in the medical literature. The patient who suffered from recurrence pancreatitis was taken to hospital in septic condition. In the background of the septic condition lied the acut exacerbate of pancreatitis. Besides, in the right side of the thoracic cavity as well as in the peritoneal cavity fistulas of pancreal tail's pseudocyst was found. It was proved by clinical, laboratory and imaging procedure examinations. During the operation external drainage of the pseudocyst was carried out. After several thoracocentesis chylothorax was developed which was cured by permanent chest tube drainage.  相似文献   
73.
PURPOSE: This study aims to investigate the role of gastrin-17 (G17) on angiogenesis features in gliomas both in vitro and in vivo. EXPERIMENTAL DESIGN: The influences of G17 and G17 receptor antagonists were characterized in vitro in terms of angiogenesis on human umbilical vein endothelial cell (HUVEC) tubulogenesis processes on Matrigel and in vivo with respect to U373 orthotopic glioma xenografts. The influence of phosphatidylinositol 3'-kinase, protein kinase C, and nuclear factor-kappaB inhibitors was characterized in vitro on G17-mediated HUVEC tubulogenesis. G17-mediated release of interleukin (IL)-8 from HUVECs and G17-induced modifications in nuclear factor-kappaB DNA binding activity were characterized by means of specific enzyme-linked immunosorbent assays. The influence of G17 on E- and P-selectin expression was determined by means of computer-assisted microscopy, whereas the influence of E- and P-selectin on HUVEC migration was approached by means of antisense oligonucleotides. The chemotactic influence of G17 and IL-8 on HUVEC migration was characterized by means of computer-assisted videomicroscopy with Dunn chambers. RESULTS: Messenger RNAs for cholecystokinin (CCK)A, CCKB, and CCKC receptors were present in HUVECs and microvessels dissected from a human glioblastoma. Whereas G17 significantly increased the levels of angiogenesis in vivo in the U373 experimental glioma model and in vitro in the HUVECs, the CCKB receptor antagonist L365,260 significantly counteracted the G17-mediated proangiogenic effects. G17 chemoattracted HUVECs, whereas IL-8 failed to do so. IL-8 receptor alpha (CXCR1) and IL-8 receptor beta (CXCR2) mRNAs were not detected in these endothelial cells. Gastrin significantly (but only transiently) decreased the level of expression of E-selectin, but not P-selectin, whereas IL-8 increased the expression of E-selectin. Specific antisense oligonucleotides against E- and P-selectin significantly decreased HUVEC tubulogenesis processes in vitro on Matrigel. CONCLUSIONS: The present study shows that gastrin has marked proangiogenic effects in vivo on experimental gliomas and in vitro on HUVECs. This effect depends in part on the level of E-selectin activation, but not on IL-8 expression/release by HUVECs.  相似文献   
74.
Anterior knee pain is a common presenting complaint amongst adolescent athletes. We hypothesised that patellar tendinopathy may occur at a younger age than is generally recognised. Thus, we studied the patellar tendons in 134 elite 14- to 18-year-old female (n=64) and male (n=70) basketball players and 29 control swimmers (17 female, 12 male) clinically and with ultrasonography. We found that of 268 tendons, 19 (7%) had current patellar tendinopathy on clinical grounds (11% in males, 2% in females). Twenty-six percent of the basketball players' patellar tendons contained an ultrasonographic hypoechoic region. Ultrasonographic abnormality was more prevalent in the oldest tertile of players (17-18 years) than the youngest tertile (14-15.9 years). Of tendons categorised clinically as 'Never patellar tendinopathy', 22% had an ultrasonographic hypoechoic region nevertheless. This study indicates that patellar tendinopathy can occur in 14- to 18-year-old basketball players. Ultrasonographic tendon abnormality is 3 times as common as clinical symptoms.  相似文献   
75.
Corpora amylacea (C.A.) also named polyglucosan bodies (P.B.) are one of the hallmarks of normal brain aging. Although their functions are not yet clear, C.A. increase in number in patients suffering from neurodegenerative diseases. C.A. contain 88% of hexoses and 4% of proteins. Most of the proteins in C.A. are aging or stress proteins such as heat shock proteins, ubiquitinated proteins and advanced glycation end products which are also proinflammatory products. Stimulated by the potential role played by some S100 proteins in the inflammatory process which may be triggered in C.A., we investigated, by immunohistochemistry, the presence of different S100 proteins (S100A1, S100A2, S100A3, S100A4, S100A5, S100A6, S100A8, S100A9, S100A12 and S100B) in C.A. from normal human brain. Among the ten S100 proteins analyzed, nine (S100A) were detected in C.A. Three S100 proteins (S100A8, S100A9, S100A12) which are highly expressed in activated macrophages and used as inflammatory markers were detected in C.A. S100A8 was, in addition, found in thick neuronal processes from the pons. One (S100B) could not be found in C.A. although it was highly expressed in astrocytes. In C.A., the staining intensity was estimated by computer-assisted microscopy and gave the following order: S100A1 congruent withS100A8 congruent with S100A9>S100A5> or =S100A4>S100A12>S100A6> S100A2=S100A3. The potential inflammatory role played by S100 proteins in C.A. is discussed.  相似文献   
76.
77.
PURPOSE: The present review aims to emphasize that malignant gliomas are characterized by the diffuse invasion of distant brain tissue by a myriad of single migrating cells that exhibit decreased levels of apoptosis (programmed cell death type I), thus a resistance to cytotoxic insult. METHODS: The present review surveys the molecular mechanisms of migration in malignant gliomas and potential issues arising from treatments, in addition to relationships between glioma cell migration and resistance to apoptosis in terms of the molecular signaling pathways. RESULTS: Clinical and experimental data demonstrate that glioma cell migration is a complex combination of multiple molecular processes, including the alteration of tumor cell adhesion to a modified extracellular matrix, the secretion of proteases by the cells, and modifications to the actin cytoskeleton. Intracellular signaling pathways involved in the acquisition of resistance to apoptosis by migrating glioma cells concern PI3K, Akt, mTOR, NF-kappaB, and autophagy (programmed cell death type II). CONCLUSION: A number of signaling pathways can be constitutively activated in migrating glioma cells, thus rendering these cells resistant to cytotoxic insults. However, these pathways are not all constitutively activated at the same time in any one glioma. Particular inhibitors should therefore only be chosen if the target is present in the tumor tissue, but this is only possible if individual patients are submitted to the molecular profiling of their tumors before undergoing any treatment to combat their migratory glioma cells. Specific antimigratory compounds should be added to conventional radio- and/or chemotherapy.  相似文献   
78.
79.
80.
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