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   3022篇
  免费   2篇
综合类   3篇
化学工业   9篇
建筑科学   1篇
轻工业   1篇
水利工程   1篇
石油天然气   2篇
无线电   1篇
一般工业技术   4篇
冶金工业   2995篇
自动化技术   7篇
  2024年   1篇
  2021年   1篇
  2014年   2篇
  2013年   1篇
  2012年   4篇
  2011年   1篇
  2010年   1篇
  2008年   1篇
  2005年   3篇
  2004年   1篇
  2003年   5篇
  2002年   1篇
  2001年   1篇
  1999年   88篇
  1998年   887篇
  1997年   492篇
  1996年   314篇
  1995年   169篇
  1994年   148篇
  1993年   171篇
  1992年   25篇
  1991年   35篇
  1990年   38篇
  1989年   45篇
  1988年   53篇
  1987年   54篇
  1986年   35篇
  1985年   33篇
  1983年   11篇
  1982年   14篇
  1981年   20篇
  1980年   38篇
  1979年   4篇
  1978年   12篇
  1977年   93篇
  1976年   215篇
  1975年   6篇
  1955年   1篇
排序方式: 共有3024条查询结果,搜索用时 15 毫秒
71.
72.
The ability of morphine to modify sucrose palatability was assessed by the taste reactivity test. In Experiment 1, rats were injected with morphine (0.0, 0.5, 2.0, and 10.0 mg/kg, subcutaneously), 30 min before receiving a 10-min intraoral infusion of 2% or 20% sucrose solution. A dose of 2.0 mg/kg morphine enhanced ingestive reactions elicited by both concentrations of sucrose solution. In Experiment 2, the interval between morphine pretreatment and the taste reactivity test was manipulated. Rats given 2.0 mg/kg morphine 30 or 120 min before testing displayed enhanced ingestive reactions elicited by 20% sucrose solution during the first 5 min of a 10-min test. The results support the hypothesis that morphine enhances the hedonic assessment of sucrose solution.  相似文献   
73.
A 2-year trial was conducted to evaluate the cost-effectiveness of heliotherapy for psoriasis. The course and cost of psoriasis of 46 Finnish patients were first closely monitored for 1 year, then the patients received a 4-week supervised heliotherapy treatment in the Canary Islands, Spain, after which they continued to be followed for another year. Heliotherapy dramatically reduced the severity of psoriasis and also seemed to have favourable long-term effects on psoriasis. The mean direct cost of the 4-week heliotherapy for one patient was FIM12,289 (1 Pound = FIM7.0 in 1989). The cost of flights and half-board in Spain formed nearly 60% (FIM7033) of the total cost. In the year preceding heliotherapy, the mean direct annual cost of antipsoriasis therapy was FIM7335 and in the year after FIM5700, a reduction of 22% in annual costs; this change was not statistically significant because there were large variations in costs among patients. The costs of heliotherapy exceeded manyfold the mean monthly cost of conventional psoriasis therapy. There were no overall savings using heliotherapy in those patients suffering mainly from moderately severe psoriasis. Heliotherapy saved costs only in those patients with severe psoriasis that required expensive medication or ward treatment. Although heliotherapy cannot be regarded as an economical treatment for the average patients with psoriasis, it clears psoriasis effectively and is preferred by patients. Thus, heliotherapy constitutes an alternative for patients suffering severe psoriasis.  相似文献   
74.
Asplenia syndrome in conjoined twins: a case report   总被引:1,自引:0,他引:1  
Incomplete fission of the primordial cell mass is generally believed to be the cause of conjoined twinning. It may also explain the tendency towards increased symmetry in these twins. We report a case of the rostral duplication type of conjoined twins with an absence of symmetry; one twin had the asplenia syndrome, whereas the other twin was normal. Local environmental factors acting upon the organ anlage may explain the asymmetric development in these conjoined twins.  相似文献   
75.
大家在筛选录像的时候会发现,每一场DOTA2比赛都有自己的等级,分为普通、高、非常高三种。比赛的等级是由每个人的Matchmarkingranking数值所决定的,我们简称其为MMR值,与天梯积分有点像。  相似文献   
76.
The Ab response of a healthy adult to the first dose of a Haemophilus influenzae type b capsular polysaccharide (HibCP) conjugate vaccine was studied at the level of Ig gene usage by circulating Ab-secreting cells. Forty-one IgA and 17 IgG mRNA sequences were obtained. The major part of the response was confined to IgA Ab-secreting cells, and 72% of the IgA sequences were derived from the progeny of a single rearranged B cell. These sequences could be arranged in a genealogical tree showing multiple somatic mutations and at least two intraclonal isotype switches to IgA2. Fourteen somatic mutations were shared by this clonal progeny, indicating that extreme clonal selection had occurred early in the clonal development. Taking into account the frequency of somatic mutations and the clone size, it was evident that the responding cell population must have originated from a mutated, highly selected, and expanded population of cells existing before vaccination, i.e., memory B cells. The dominating heavy and light chains of the response were combined in a Fab that bound HibCP. It was shown that the shared heavy and light chain mutations increased the affinity for HibCP considerably, indicating that the clonal selection had been driven by affinity. Pre-existing memory cells in unvaccinated adults may explain several features of Ab responses to polysaccharide vaccines and may play a role in acquiring the ability to respond to pure polysaccharides during infancy.  相似文献   
77.
Neuromuscular disease commonly affects the rearfoot as equinus, equinovarus, and equinovalgus deformity. Spastic hemiplegia caused by stroke, head injury, and cerebral palsy results in equinovarus deformity of the rearfoot. Spastic diplegia, most frequently caused by cerebral palsy, results in equinovalgus rearfoot deformity. Problems in ambulation, footwear, and bracing, as well as their orthopedic management, in patients with neuromuscular disease are discussed in a case-report format.  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