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   796篇
  免费   0篇
  国内免费   3篇
电工技术   6篇
化学工业   3篇
金属工艺   3篇
轻工业   1篇
一般工业技术   1篇
冶金工业   784篇
自动化技术   1篇
  2019年   1篇
  2016年   1篇
  2011年   1篇
  2008年   1篇
  2003年   1篇
  1999年   18篇
  1998年   235篇
  1997年   153篇
  1996年   108篇
  1995年   46篇
  1994年   39篇
  1993年   36篇
  1992年   6篇
  1991年   11篇
  1990年   10篇
  1989年   14篇
  1988年   5篇
  1987年   4篇
  1986年   8篇
  1985年   7篇
  1983年   2篇
  1982年   3篇
  1981年   1篇
  1980年   10篇
  1979年   1篇
  1978年   2篇
  1977年   20篇
  1976年   52篇
  1975年   1篇
  1972年   1篇
  1955年   1篇
排序方式: 共有799条查询结果,搜索用时 9 毫秒
51.
Nutrition in the fetus and the premature infant is a rapidly changing field, not solely due to the acquisition of new knowledge but also because there have been major conceptual advances that have altered our approach to nutrition during early stages of development. This special report will highlight some of these conceptual advances in this area.  相似文献   
52.
53.
Hearing loss in patients with ischemic heart disease traditionally has been attributed to atheromatous cerebral vascular disease. In this study, the site of the auditory lesion was sought in patients with ischemic heart disease and perceptive hearing loss. Standard brainstem evoked response audiometry (BSER) with increased stimulation rate (ISR) were performed. Sixty-seven patients admitted for coronary artery disease were examined. Fifty-seven recordings were complete and evaluable. All the cases of hearing loss were endocochlear. In 4 patients. BSER and ISR detected subclinical retrocochlear lesions that were compatible with ischemic disease. The results suggest that selective early cochlear ischemia can occur in young persons with heart disease. The sensitivity of BSER with ISR for detecting ischemic brainstem lesions was confirmed.  相似文献   
54.
OBJECTIVE: To determine the association of parent, family, and child factors with mental health services need and utilization. METHOD: Possible determinants of services need and utilization were assessed in a general population sample of 2,227 children aged 4 to 18 years. RESULTS: 3.5% of the total sample had been referred for mental health services within the past year. The most potent factors associated with service need and utilization were the child's problem behaviors (both internalizing and externalizing) and academic problems and family stress. Socioeconomic factors and the child's sex were not in itself associated with help-seeking factors. Parental psychopathology, life events, and family psychopathology lowered the parents' threshold for evaluating the child's behavior as problematic but did not increase the likelihood of referral. CONCLUSION: Referred children are more likely to live in families under stress than are children with the same level of problems who live in well-functioning families. Clinicians and researchers who make inferences from findings in clinical samples should realize, therefore, that children from problem families are overrepresented in their samples.  相似文献   
55.
Divalproex sodium is an effective drug for the treatment of migraine. Most adverse drug events are transient and not of great clinical concern. Although rare, well-documented examples of liver toxicity have been reported in children under 2 years of age on polypharmacy. Additional cases occur in children under 10 who are receiving polypharmacy, particularly those who have intractable seizures and degenerative central nervous system disease. Clinicians who treat migraineurs with divalproex sodium do not need to be overly preoccupied with monitoring of drug levels and liver function tests. The most valuable test is clinical observation of the patient.  相似文献   
56.
Essential hypertension is a polygenic disease. Various genes responsible for rare monogenic forms of hypertension have been identified in the recent years. These are glucocorticoid remediable aldosteronism (GRA), Liddle's syndrome and apparent mineralocorticoid excess (AME). A fourth form, the Bilginturan syndrome is associated with brachydactyly and resembles essential hypertension. The investigations of the pathomechanisms in these rare diseases can help us to understand common hypertension.  相似文献   
57.
The surface microtopography of normal human skin varies from one anatomical region to another. The patterns at different sites are considered to reflect different orientations of dermal fibers. A simple technique is described that enables such orientations to be accurately delineated. Various scars resulting from lacerations, surgical incisions, and steroid-induced striae were examined in the manner described.  相似文献   
58.
Using a food-reinforced two-lever operant method, rats (n=5) could be trained to discriminate 10 mg/kg cocaine from saline. Stimulus generalization experiments with lower doses (0.31-5.0 mg/kg) revealed that the cocaine cue is a dose-related phenomenon. Neuroleptic drugs were found relatively ineffective as possible antagonists of the cocaine cue, and no antagonistic effect whatsoever was obtained with dibenamine, propranolol, cyproheptadine and methysergide. iamphetamine (1.25 mg/kg) and apomorphine (0.31 mg/kg) were generalized with cocaine, and a dopaminergic involvement is discussed.  相似文献   
59.
60.
Four structurally related peptides with potent growth-inhibitory activity towards Escherichia coli were isolated from an extract of the stomach of the European green frog Rana esculenta, and were identified as members of the brevinin-2 family. Two peptides, termed brevinin-2Eg (GIMDTLKNLA10 KTAGKGALQS20 LLNHASCK LS30GQC) and brevinin-2Eh (GIMDTLKNLA10 KTAGKGALQS20 LLNHASCKL S30 KQC) have not been described previously. One peptide is identical to brevinin-2Ec, previously isolated from R. esculenta skin secretions, and one peptide is identical to brevinin-2Ef whose structure has been deduced from a cloned cDNA prepared from a R. esculenta skin cDNA library. The data demonstrate that certain peptides of the brevinin-2 family, like the magainins in the toad, Xenopus laevis, may play an important role in protecting the gastrointestinal tract of Ranid frogs against microbial invasion.  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