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   2910篇
  免费   0篇
电工技术   7篇
化学工业   76篇
金属工艺   27篇
机械仪表   26篇
建筑科学   17篇
矿业工程   8篇
能源动力   1篇
轻工业   1篇
水利工程   9篇
石油天然气   18篇
无线电   51篇
一般工业技术   130篇
冶金工业   2501篇
原子能技术   29篇
自动化技术   9篇
  2022年   6篇
  2021年   6篇
  2020年   9篇
  2019年   8篇
  2018年   24篇
  2017年   18篇
  2016年   19篇
  2015年   5篇
  2014年   12篇
  2013年   24篇
  2012年   18篇
  2011年   23篇
  2010年   10篇
  2009年   13篇
  2008年   10篇
  2007年   8篇
  2006年   16篇
  2005年   8篇
  2004年   7篇
  2003年   8篇
  2002年   6篇
  2001年   9篇
  2000年   5篇
  1999年   62篇
  1998年   777篇
  1997年   461篇
  1996年   286篇
  1995年   190篇
  1994年   109篇
  1993年   154篇
  1992年   25篇
  1991年   27篇
  1990年   27篇
  1989年   22篇
  1988年   33篇
  1987年   34篇
  1986年   24篇
  1985年   19篇
  1984年   5篇
  1983年   5篇
  1982年   14篇
  1981年   31篇
  1980年   27篇
  1979年   4篇
  1978年   9篇
  1977年   89篇
  1976年   164篇
  1975年   9篇
  1973年   5篇
  1970年   5篇
排序方式: 共有2910条查询结果,搜索用时 15 毫秒
11.
Cell cycle. The NIMA kinase joins forces with Cdc2   总被引:1,自引:0,他引:1  
The NIMA and Cdc2 protein kinases cooperate to regulate mitosis in Aspergillus nidulans. NIMA-related pathways have now begun to emerge in higher eukaryotes.  相似文献   
12.
13.
The anisotropy of the resistivity and thermoelectric power (TEP)S of Nd1.85Ce0.15CuO4?δ single crystal (T c =17 K) has been investigated. In the temperature rangeT c <T<300 K the ratioρ cab≈104 and the dependencesρ ab (T) andρ c (T) change from quadratic to linear atT~200 K. The dependencesS ab (T) andS c (T) reach a maximum atT>T c and then decrease almost linearly with increasing temperature, changing sign from positive to negative nearT~ 150 K. The features of the resistivity and TEP temperature dependences (the lawρT 2 changing toρ∝T, the change in the sign of S with temperature, and the low TEP anisotropy at largeρ anisotropy) have been interpreted in the framework of the narrow-band model.  相似文献   
14.
15.
16.
The principal neutralizing domain, IGPGRAF sequence, from the V3-loop of HIV-1 was inserted in two positions on the surface of the protein that makes up the capside shell of the insect Flock House Virus. The hybrid proteins were expressed in insect cells via recombinant baculoviruses. Three different hybrids were used as immunogens: two with a single copy of the insert in different positions of the carrier protein and a third with two copies of the insert at the same positions as before. All hybrid proteins induced strong and broad specific immune response in guinea pigs against different V3-loop sequences. However, only one of the hybrid proteins was able to induce a strong neutralizing response against MN and IIIB HIV-1 isolates. Our results demonstrate that a very short peptide sequence of HIV-1 can constitute a valuable immunogen able to induce a neutralizing response if presented to the immune system in the context of the FHV capsomer structure.  相似文献   
17.
Major clinical characteristics of ovarian hyperstimulation syndrome are described and criteria of predicting the course of this disease and measures to prevent it presented. Statistical data on the presence of this syndrome in various forms during various schemes of superovulation stimulation are offered. Optimal schemes for the treatment of the condition are suggested.  相似文献   
18.
Osteotomy has been used in treatment of unstable intertrochanteric hip fractures in an attempt to increase the stability of the fracture fragments. We have assessed this stability in a randomised prospective study on 138 patients, all having been fixed by dynamic hip screen, comparing anatomical reduction with medialisation osteotomy. The groups were similar in terms of age, gender and fracture configuration. There was no difference in final results in both groups except that operation time was longer in osteotomy group and the blood loss was more. We found no clear benefit from osteotomy and therefore recommend anatomical reduction and fixation by a sliding hip screw in most cases. Rarely, a fracture configuration which does not allow anatomical reduction may benefit from an osteotomy.  相似文献   
19.
Two once-daily electroconvulsive shocks (ECS) produced retrograde amnesia in rats trained on a Hebb-Williams maze; Verapamil (12.5 mg/kg, i.p.) or felodipine (10 mg/kg, p.o.) administered half an hour before each ECS attenuated this ECS-induced amnesia. Hence, these drugs may hold promise for the containment of amnesia induced by electroconvulsive therapy (ECT). Speculatively, one or more of several mechanisms may be involved: cerebral vasodilatation, enhancement of cholinergic tone, and inhibition of calcium-mediated impairment of neuronal function. These drugs may also act by attenuating the systolic surge in blood pressure during ECT, thereby decreasing edema due to cerebral hyperperfusion, as well as decreasing the possible transfer of potentially neurotoxic macromolecules through a putative breach in the blood-brain barrier.  相似文献   
20.
Ninety consecutive patients who were admitted to hospital with acute chest pain were followed-up five years later. At the time of the original admission, all of the patients received a detailed physical and psychiatric evaluation. Seventy-one patients were diagnosed as having ischaemic heart disease, and 19 were diagnosed as having nonspecific chest pain. Patients with nonspecific pain were younger, consumed greater amounts of alcohol, smoked more than their organic counterparts, and were more likely to suffer from psychiatric disorder. The five-year assessment was carried out using a self-report questionnaire. Of the original 71 patients with ischaemic heart disease, 14 had died; 43 questionnaires were returned, 80.2% of the original sample. Sixteen (84.9%) of the patients with nonspecific pain were followed up; none had died. Both groups were predominantly male. The patients with nonspecific pain still smoked more than the patients with ischaemic heart disease, and they had significantly more symptoms of anxiety. The overall prevalence of psychiatric morbidity remained high, however, in both groups. Patients who had psychiatric illness at the time of the original assessment were more anxious at follow-up and more likely to complain of chest pain than those who had been well. Patients with nonspecific chest pain continued to seek treatment on a regular basis from their general practitioners either for chest pain or for other symptoms, but few were in frequent contact with hospital services. The possible preventive effects of psychiatric intervention at an earlier stage in both groups of patients needs to be investigated.  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