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   5301篇
  免费   347篇
  国内免费   18篇
耳鼻咽喉   64篇
儿科学   133篇
妇产科学   127篇
基础医学   930篇
口腔科学   210篇
临床医学   645篇
内科学   920篇
皮肤病学   151篇
神经病学   603篇
特种医学   186篇
外科学   595篇
综合类   17篇
一般理论   1篇
预防医学   360篇
眼科学   74篇
药学   298篇
中国医学   8篇
肿瘤学   344篇
  2023年   47篇
  2022年   64篇
  2021年   121篇
  2020年   94篇
  2019年   106篇
  2018年   119篇
  2017年   106篇
  2016年   149篇
  2015年   153篇
  2014年   201篇
  2013年   264篇
  2012年   415篇
  2011年   434篇
  2010年   260篇
  2009年   250篇
  2008年   347篇
  2007年   368篇
  2006年   317篇
  2005年   342篇
  2004年   328篇
  2003年   288篇
  2002年   286篇
  2001年   47篇
  2000年   33篇
  1999年   45篇
  1998年   70篇
  1997年   48篇
  1996年   29篇
  1995年   39篇
  1994年   29篇
  1993年   27篇
  1992年   26篇
  1991年   15篇
  1990年   19篇
  1989年   11篇
  1988年   15篇
  1987年   14篇
  1986年   15篇
  1985年   17篇
  1984年   12篇
  1983年   6篇
  1982年   17篇
  1981年   13篇
  1980年   4篇
  1978年   9篇
  1977年   6篇
  1976年   8篇
  1975年   5篇
  1974年   7篇
  1973年   4篇
排序方式: 共有5666条查询结果,搜索用时 15 毫秒
11.
PURPOSE: Research in the field of brain injury rehabilitation has tended to regard return to work as a measure of outcome. Researchers have not paid particular attention to the experiences of people living with a brain injury. The aim of the phenomenological study reported here was to identify and describe what characterizes the meaning of work to those with acquired brain injury. METHODS: Ten participants of working age were interviewed about the meaning of work 1-5 years after being inflicted with a brain injury. Data were analyzed and interpreted using the Empirical Phenomenological Psychological method. RESULTS: The findings revealed a meaning structure consisting of four main characteristics. Work was no longer experienced as the primary event in life and the social dimension had become more important. The perceived competence and work identity were threatened after the injury. A common theme across all interviews was the struggle to return to a state of normality, and working was considered to be evidence of success. CONCLUSION: The findings described the altered meaning of work 1-5 years after brain injury. This knowledge should lead to an increased understanding among occupational therapists engaged in work rehabilitation after brain injury and can serve as a basis for individualized intervention strategies.  相似文献   
12.
13.
14.
Aim: There is strong evidence that hepatocellular apoptosis is not only initiated by circulating blood cells which become adherent within the endotoxemic liver, but also contributes to further sustain the inflammatory cell-cell response. Methods: Because previous studies assumed the importance of the role of cellular cross-talk in mediating inflammatory liver injury, we herein examined the activation of Kupffer cells (KCs) and their spatial coincidence with intrahepatic leukocyte adherence and hepatocellular apoptosis at 6 h after intraperitoneal exposure of rats with lipopolysaccharide (10 mg/kg). Results: In vivo multifluorescence microscopy revealed liver injury including nutritive perfusion failure, tissue hypoxia, leukocyte accumulation, as well as KC activation and parenchymal apoptotic cell death. Detailed spatial analysis revealed frequent colocalization of activated KCs with apoptotic hepatocytes. Colocalization was absent in saline-treated controls.Colocalization was confirmed by histochemistry, which showed ED1-positive KCs neighboring and engulfing TUNEL-positive hepatocytes. Colocalization of KCs with leukocytes ranged between 4% and 5% and did not increase in endotoxemic animals. Taken together, the present results indicate that apoptotic cell death of hepatocytes may stimulate phagocytosis by neighboring KCs. Direct KC-leukocyte contact seems not to be mandatory for cellular communication in the process of hepatocellular apoptosis. Conclusion: With respect to the fundamental importance of cell apoptosis, improved knowledge of these cell-cell interactions might allow the development of new therapeutic strategies through the regulation of apoptotic cell death.  相似文献   
15.
OBJECTIVE: The Baking Tray Task is a comprehensible, simple-to-perform test for use in assessing unilateral neglect. The aim of this study was to validate further its use with stroke patients. METHODS: The Baking Tray Task was compared with 2 versions of the Behaviour Inattention Test and a test for personal neglect. A total of 270 patients were subjected to a 3-item version of the Behaviour Inattention Test and 40 patients were subjected to an 8-item version of the Behaviour Inattention Test, besides the Baking Tray Task and the personal neglect test. RESULTS: The Baking Tray Task was more sensitive than the 3-item Behaviour Inattention Test, but the 8-item Behaviour Inattention Test was more sensitive than the Baking Tray Task. The best combination of any 3 tests was Baking Tray Task, Reading an article, and Figure copying; the 2 last-mentioned being a part of the 8-item Behaviour Inattention Test. CONCLUSION: Multi-item tests detect more cases of neglect than do single tests. However, it is tiresome for the patient to undergo a larger test battery than necessary. It is also time-consuming for the staff. Behavioural tests seem more appropriate when assessing neglect. The Baking Tray Task seems to be one of the most sensitive single tests, but its sensitivity can be further enhanced when it is used in combination with other tests.  相似文献   
16.
A proprioceptive deficit is an important determinant of disability in various shoulder disorders, such as instability and osteoarthrosis. In 15 patients with impingement syndrome stage II (Neer 1983), who were treated by arthroscopic subacromial decompression, we measured movement sense by determining threshold levels for the perception of motion of the shoulder. The patients were placed in a specially designed chair allowing continuous passive motion of the shoulder joint, while avoiding cutaneous, auditory and visual stimuli. To assess movement detection thresholds, passive abduction movements of the shoulder were performed at a starting angle of 60°, an amplitude of 10° and an angular velocity of 1.3°/s. Before surgery, all patients had higher threshold levels for the perception of motion in their affected shoulders then in the other side. After decompression, proprioception had improved on the decompressed side, but was unchanged on the other side.  相似文献   
17.
18.
Endothelial selectins are crucial for the recruitment of leukocytes into sites of inflammation. On T cells, ligands for selectins become induced upon differentiation into the effector/memory stage. Initial in vitro studies suggested a correlation between the Th1 phenotype and ligand expression, but whether this also holds true in vivo remained uncertain. We here analyzed selectin ligands on CD4+ T cells producing IFN-gamma, IL-4 or IL-10, prototypic cytokines of the Th1, Th2 and Tr1 subset, respectively. We analyzed mice infected with influenza virus, the bacterium Listeria, and the parasites Toxoplasma (all Th1 models) or Nippostrongylus (Th2 model). A link between the Th1 phenotype and ligand expression was not found in vivo. Surprisingly, the potentially regulatory IL-10-producing T cells displayed the highest frequency of ligand-positive cells in general. Within the inflamed tissues, the frequencies of P-selectin-binding cells increased in the dominant subset, either Th1 or Th2. Up-regulation was also found for E-selectin ligands during influenza, but not Nippostrongylus infection. In conclusion, conditions driving T cell polarization into either Th1 or Th2 in vivo do not affect the expression of selectin ligands, but acquisition of P-selectin binding and hence migration into inflamed tissues is boosted by an inflammatory milieu.  相似文献   
19.
Oxytocin treatment in rats induces long-lasting antistress and growth promoting effects. This study investigated whether prolyl-leucyl-glycinamide (PLG) (the c-terminal tripeptide of oxytocin) or tocinoic acid (the ring structure of oxytocin) could induce some of these effects in male rats. For this purpose, PLG (2 or 10 mg/kg, s.c.) or tocinoic acid (1 mg/kg, s.c.) was administered to rats once a day for 3 or 5 days. Blood pressure, heart rate, spontaneous motor activity, nociceptive thresholds, and the survival of ischaemic musculocutaneous flaps were measured. In addition, endogenous oxytocin levels and plasma levels of some hormones known to be influenced by oxytocin were determined. PLG (2 mg/kg, s.c., but not 10 mg/kg, s.c.) decreased diastolic blood pressure (p<0.05) and locomotor activity (p<0.05). PLG (10 mg/kg, s.c.) decreased gastrin (p<0.05) and endogenous oxytocin levels in plasma (p<0.01). Tocinoic acid decreased locomotor activity (p<0.05), but did not affect any of the other parameters measured. In conclusion, this study showed that both PLG and tocinoic acid decrease locomotor activity. In addition, PLG also induced some other effects similar to those induced by oxytocin treatment but when administered in high doses it decreased oxytocin levels.  相似文献   
20.
Paper copies of digital radiographs printed with the continuous ink-jet technique have proved to be of a high enough quality for demonstration purposes. We present a study on the image quality of ink-jet printed paper copies of digital chest radiographs, based on receiver operating characteristic (ROC) analysis. Eighty-three digital radiographs of a chest phatom with simulated tumors in the mediastinum and right lund, derived from a computed radiography (CR) system were presented in two series of hard copies as ink-jet printed paper copies and as laser recorded film. The images, with a matrix of 1,760×2,140 pixels, were printed with a spatial resolution of 10 pixels/mm in the CR film recorder as well as in the ink-jet printer. On film, every image was recorded in two versions, one optimized for the mediastinum and one for the lungs. On paper, only one image was printed; this constituted an effort to optimize both the mediastinum and the lungs. The ink-jet printed images, printed on a matt coated paper, were viewed as on-sight images with reflected light. The exdaminations were reviewed by six radiologists, and ROC curves were constructed. No significant difference was found between the performance of film and that of ink-jet paper prints. Because the cost for a paper copy is only a tenth of that of film, remarkable cost reductions can be achieved by using the ink jet technique instead. Our results show that further quality studies of ink-jet printed images are worthwhile.  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