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   986篇
  免费   38篇
电工技术   6篇
化学工业   80篇
机械仪表   18篇
建筑科学   20篇
矿业工程   1篇
能源动力   12篇
轻工业   99篇
水利工程   9篇
石油天然气   4篇
无线电   89篇
一般工业技术   171篇
冶金工业   449篇
原子能技术   6篇
自动化技术   60篇
  2023年   3篇
  2021年   4篇
  2019年   5篇
  2018年   5篇
  2017年   8篇
  2016年   17篇
  2015年   11篇
  2014年   9篇
  2013年   28篇
  2012年   17篇
  2011年   18篇
  2010年   23篇
  2009年   25篇
  2008年   33篇
  2007年   24篇
  2006年   32篇
  2005年   26篇
  2004年   25篇
  2003年   28篇
  2002年   23篇
  2001年   19篇
  2000年   28篇
  1999年   31篇
  1998年   140篇
  1997年   71篇
  1996年   55篇
  1995年   45篇
  1994年   46篇
  1993年   44篇
  1992年   11篇
  1991年   11篇
  1990年   18篇
  1989年   11篇
  1988年   16篇
  1987年   11篇
  1986年   11篇
  1985年   14篇
  1984年   3篇
  1983年   7篇
  1982年   4篇
  1981年   9篇
  1980年   5篇
  1978年   5篇
  1977年   8篇
  1976年   11篇
  1973年   4篇
  1969年   2篇
  1966年   2篇
  1963年   2篇
  1961年   2篇
排序方式: 共有1024条查询结果,搜索用时 109 毫秒
1.
In response to recent calls in the literature for within-person examinations of social support processes over time, this study explores the relationships of spousal support, spousal strain, and well-being among husbands and wives, both within the same day and across days. Eighty-three couples were interviewed and completed a structured diary twice daily for 1 week. The results of multilevel hierarchical modeling suggest that both spousal support and spousal strain made significant, independent contributions to concurrent negative affect, although only spousal support was a significant predictor of next-day negative affect. Spousal strain interacted with spousal support to predict next-day negative affect. Direct and moderating effects of perceived marital adjustment on negative affect were discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
2.
An implicit assumption of several causal reasoning models is that readers adopt the goals of a narrative's protagonist during text comprehension. In apparent violation of this assumption, readers participating in Experiment 1 of the present study drew inferences relevant to a protagonist's goal even when that goal was already satisfied from the perspective of the protagonist. In Experiments 2 and 3, participants were explicitly asked to view the text situation from the point of view of the protagonist. In this case, the goals of the reader and the protagonist should be the same. In these experiments, participants focused on the goals of the protagonist only when those goals had not been satisfied from the perspective of the protagonist. These results are discussed in terms of reader- and character-based perspectives and in terms of text characteristics that cue perspective taking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
3.
4.
We report on the demonstration of optically pumped photonic crystal lasers with InAs quantum dot active regions operating at room temperature near 1310 nm. Absorbed threshold pump powers as low as 25 /spl mu/W are observed. We also extract a characteristic temperature of 17 K, which is attributed to limitations caused by surface recombination.  相似文献   
5.
6.
7.
The immune-mediated graft-versus-leukemia effect is important to prevent relapse after allogeneic progenitor cell transplantation. This process requires engraftment of donor immuno-competent cells. The objective of this study was to assess the feasibility of achieving engraftment of allogeneic peripheral blood or bone marrow progenitor cell after purine analog containing nonmyeloablative chemotherapy. Patients with advanced leukemia or myelodysplastic syndromes (MDS) who were not candidates for a conventional myeloablative therapy because of older age or organ dysfunction were eligible. All patients had an HLA-identical or one-antigen-mismatched related donor. Fifteen patients were treated (13 with acute myeloid leukemia and 2 with MDS). The median age was 59 years (range, 27 to 71 years). Twelve patients were either refractory to therapy or beyond first relapse. Eight patients received fludarabine at 30 mg/m2/d for 4 days with idarubicin at 12 mg/m2/d for 3 days and ara-c at 2 g/m2/d for 4 days (n = 7) or melphalan at 140 mg/m2/d (n = 1). Seven patients received 2-chloro-deoxyadenosine at 12 mg/m2/d for 5 days and ara-C 1 at g/m2/d for 5 days. Thirteen patients received allogeneic peripheral blood stem cells and 1 received bone marrow after chemotherapy. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and methyl-prednisolone. Treatment was generally well tolerated, with only 1 death from multiorgan failure before receiving stem cells. Thirteen patients achieved a neutrophil count of greater than 0.5 x 10(9)/L a median of 10 days postinfusion (range, 8 to 17 days). Ten patients achieved platelet counts of 20 x 10(9)/L a median of 13 days after progenitor cell infusion (range, 7 to 78 days). Eight patients achieved complete remissions (bone marrow blasts were < 5% with neutrophil recovery and platelet transfusion independence) that lasted a median of 60 days posttransplantation (range, 34 to 170+ days). Acute GVHD grade > or = 2 occurred in 3 patients. Chimerism analysis of bone marrow cells in 6 of 8 patients achieving remission showed > or = 90% donor cells between 14 and 30 days postinfusion, and 3 of 4 patients remaining in remission between 60 and 90 days continued to have > or = 80% donor cells. We conclude that purine analog-containing nonmyeloablative regimens allow engraftment of HLA-compatible hematopoietic progenitor cells. This approach permits us to explore the graft-versus-leukemia effect without the toxicity of myeloablative therapy and warrants further study in patients with leukemia who are ineligible for conventional transplantation with myeloablative regimens either because of age or concurrent medical conditions.  相似文献   
8.
Previous research demonstrated a contradiction effect: Although text currently being processed was locally coherent, readers were aware of inconsistencies between a protagonist's actions and characteristics of the protagonists that were described earlier in the text and subsequently backgrounded. In the present experiments, not only the critical characteristics but also the protagonist were backgrounded. When the protagonist was reintroduced into the narrative in the context of carrying out an inconsistent action, the contradiction effect again occurred. In Exps 1–3, we examined the effects of several variables on the onset of the effect. In Exp 4, we presented probes at various points in the passage with results that supported the conclusion that the critical characteristics had been backgrounded before the sentence that contradicted them. Results are discussed in terms of several recent models in which currently active representational elements serve as retrieval cues for other inactive, but highly related, elements. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
Traumatic aneurysms (TAs) are an unusual etiology for late neurological deterioration after traumatic brain injury (TBI) and represent less than 1% of all cerebral aneurysms. TAs most often are diagnosed acutely but may be delayed in presentation. To increase awareness of this serious but treatable condition when diagnosed early, we report a delayed TA after a motor vehicle accident. The patient experienced a seizure on day 46 postinjury while in rehabilitation and demonstrated persistent lethargy and hemiparesis. Neuroimaging revealed a large, ruptured left pericallosal artery TA, which was surgically clipped. The patient completed his rehabilitation course and was eventually discharged home with family. Among TBIs, TAs are associated with penetrating injuries and skull base or anterior cranial fossa fractures. Associated mortality is high, especially if rupture has occurred. Although TAs are rare, the clinician should be vigilant in the at-risk patient.  相似文献   
10.
Two patients are presented where internal mammary artery grafting was performed for the relief of symptomatic coronary artery disease. At follow-up the internal mammary artery was occluded and a communication between the internal mammary vein and the native coronary artery was demonstrated. These patients were characterised by the early recurrence of angina or the appearance of a continuous murmur. Both patients were treated by re-operation with ligation of the arterio-venous fistula and saphenous vein grafting.  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