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   940篇
  免费   1篇
化学工业   4篇
金属工艺   1篇
轻工业   1篇
石油天然气   1篇
一般工业技术   5篇
冶金工业   929篇
  2016年   1篇
  2015年   1篇
  2007年   1篇
  2005年   2篇
  2004年   1篇
  2003年   1篇
  2000年   1篇
  1999年   22篇
  1998年   282篇
  1997年   121篇
  1996年   126篇
  1995年   68篇
  1994年   55篇
  1993年   43篇
  1992年   6篇
  1991年   22篇
  1990年   10篇
  1989年   21篇
  1988年   11篇
  1987年   14篇
  1986年   13篇
  1985年   17篇
  1982年   6篇
  1981年   5篇
  1980年   7篇
  1978年   5篇
  1977年   24篇
  1976年   52篇
  1975年   2篇
  1958年   1篇
排序方式: 共有941条查询结果,搜索用时 0 毫秒
161.
162.
163.
164.
In 84 patients the wrist pulses were lost after diagnostic left heart catheterization via the brachial artery. Sixty-six of these patients underwent surgical exploration of the brachial artery for restoration of pulsatile arterial flow to the hand. This aim was achieved in 64 instances. In all cases, the artery was found to be occluded by fresh thrombus. In 36 patients, balloon thrombectomy and accurate arterial closure were successful. In the remainder, in addition to thrombectomy, indentification of an area of damage to the arterial wall required additional surgical measures, usually in the form of resection and anastomosis. The surgical approach to this problem and the importance of the recognition and treatment of arterial wall damage by the catheter are stressed in this paper.  相似文献   
165.
166.
In dogs subjected to gravitational overloadings (+Gx) according to a special training schedule the wall structure of the main arteries (carotid, humeral, femoral and aorta) was studied by histological methods. The amount of catecholamines (adrenaline and noradrenaline) in the venous blood plasma and in the adrenal tissue was the index of the sympathoadrenal system condition. It was demonstrated that in trained animals the tolerance threshold to continuously increasing overloadings (+Gx) rose. It was accompanied by an elevated amount of catecholamines in blood and the adrenals In the walls of the main arteries studied a moderate hyperelastosis and a slight collagenization of the adventitia was noted. All parts of the microcirculatory bed were moderately dilated, which favoured a better blood outflow. The data obtained demonstrate adaptational changes, which can be interpreted as indices of training and reliability of the organism.  相似文献   
167.
168.
OBJECTIVE: To determine if gabapentin is effective either as adjunctive treatment or as monotherapy for major affective disorders in a naturalistic setting. METHOD: All charts of patients meeting DSM-IV criteria for bipolar disorder or unipolar major depressive disorder treated with gabapentin in a private psychiatric practice were reviewed and clinical response was assessed retrospectively using the Clinical Global Impressions scale for Improvement (CGI-I). RESULTS: Gabapentin was moderately to markedly effective in 30% (15/50) of patients, with statistically nonsignificant differences between patients with bipolar disorder type I, bipolar disorder type II and NOS, and unipolar major depressive disorder. 70% reported side effects, mainly sedation, with 16% of the total sample discontinuing treatment due to adverse events. CONCLUSION: Gabapentin appears to be somewhat effective as add-on treatment in a subgroup of patients with mood disorders in a naturalistic setting. Prospective, controlled studies are required to clarify these pilot data.  相似文献   
169.
We investigate the effect of the neuron characteristics on the behavior of a recurrent excitatory neural network model. First, we present the different types of dynamics obtained with simulations of a network of coupled excitatory spike-response neuron models placed under the influence of noise. Then, we derive a discrete map describing the dynamics of large fully connected networks. By studying the bifurcation structure of this map, we can determine for which ranges of the neuron model parameters the network will display collective oscillations or other types of dynamics.  相似文献   
170.
DNA-based immunization strategies designed to elicit cellular antitumor immunity offer an attractive alternative to protein- or peptide-based approaches. In the present study we have evaluated the feasibility of DNA vaccination for the induction of CTL reactivity to five different melanoma Ags in vitro. Cultured, monocyte-derived dendritic cells (DC) were transiently transfected with plasmid DNA encoding human MART-1/Melan-A, pMel-17/gp100, tyrosinase, MAGE-1, or MAGE-3 by particle bombardment and used to stimulate autologous PBMC responder T cells. CTL reactivity to these previously identified melanoma Ags was reproducibly generated after two or three stimulations with genetically modified DC. Co-ordinate transfection of two melanoma Ag cDNAs into DC promoted CTL responders capable of recognizing epitopes from both gene products. Coinsertion of genes encoding the Th1-biasing cytokines IL-12 or IFN-alpha consistently enhanced the magnitude of the resulting Ag-specific CTL reactivity. Importantly, DC transfected with a single melanoma Ag cDNA were capable of stimulating Ag-specific CTL reactivity restricted by multiple host MHC alleles, some of which had not been previously identified. These results support the inherent strengths of gene-based vaccine approaches that do not require prior knowledge of responder MHC haplotypes or of relevant MHC-restricted peptide epitopes. Given previous observations of in situ tumor HLA allele-loss variants, DC gene vaccine strategies may elicit a greater diversity of host therapeutic immunity, thereby enhancing the clinical utility and success of such approaches.  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