全文获取类型
收费全文 | 1495篇 |
免费 | 3篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 49篇 |
金属工艺 | 78篇 |
机械仪表 | 3篇 |
建筑科学 | 6篇 |
轻工业 | 11篇 |
无线电 | 30篇 |
一般工业技术 | 17篇 |
冶金工业 | 1251篇 |
原子能技术 | 3篇 |
自动化技术 | 48篇 |
出版年
2013年 | 3篇 |
2012年 | 6篇 |
2011年 | 8篇 |
2010年 | 3篇 |
2009年 | 7篇 |
2008年 | 5篇 |
2007年 | 8篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 14篇 |
2003年 | 19篇 |
2002年 | 13篇 |
2001年 | 14篇 |
2000年 | 11篇 |
1999年 | 34篇 |
1998年 | 328篇 |
1997年 | 214篇 |
1996年 | 132篇 |
1995年 | 86篇 |
1994年 | 68篇 |
1993年 | 75篇 |
1992年 | 18篇 |
1991年 | 16篇 |
1990年 | 20篇 |
1989年 | 12篇 |
1988年 | 26篇 |
1987年 | 21篇 |
1986年 | 12篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 12篇 |
1982年 | 16篇 |
1981年 | 8篇 |
1980年 | 17篇 |
1979年 | 5篇 |
1978年 | 11篇 |
1977年 | 48篇 |
1976年 | 86篇 |
1975年 | 7篇 |
1973年 | 5篇 |
1971年 | 5篇 |
1970年 | 5篇 |
1969年 | 4篇 |
1968年 | 3篇 |
1964年 | 5篇 |
1955年 | 3篇 |
1947年 | 3篇 |
1942年 | 3篇 |
1928年 | 3篇 |
1924年 | 2篇 |
排序方式: 共有1498条查询结果,搜索用时 15 毫秒
1.
Barch Deanna M.; Mitropoulou Vivian; Harvey Philip D.; New Antonia S.; Silverman Jeremy M.; Siever Larry J. 《Canadian Metallurgical Quarterly》2004,113(4):556
Research suggests that schizotypal personality disorder (SPD) is a part of the spectrum of schizophrenia-related illnesses. This article hypothesizes that a deficit in the representation and maintenance of context is a core cognitive disturbance in schizophrenia and that SPD individuals should demonstrate context-processing deficits. To test this hypothesis, the authors administered 3 versions of their AX-CPT task, designed to assess context processing, to 35 healthy controls and 26 individuals with DSM-IV SPD. They also administered working memory and selective attention tasks. SPD individuals displayed context representation deficits similar to those found in schizophrenia but did not show the same additional deficits in context maintenance. Context processing was strongly associated with working memory and selective attention performance in the SPD individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
3.
Extracellular single-unit discharges were obtained from 165 spontaneously active neurons within the region of the rostral ventrolateral medulla (RVLM) by glass microelectrode from 89 brain slices of the Sprague-Dawley rats. The units could be divided into three types: regular (61.8%), irregular (24.2%) and silent (14%). Acetylcholine (ACh, 0.1, 0.3 mumol/L) showed four kinds of effects on spontaneous discharges of RVLM neurons: excitatory, inhibitory, biphasic and non-responsive, counting respectively 41.8%, 20%, 3% and 35.2% of the neurons tested. The excitatory effect of ACh was dose-dependent. The effects, either excitatory or inhibitory, of ACh (n = 49) were mostly blocked by atropine (0.3 mumol/L, n = 42). The excitatory effect of ACh (n = 14) could be blocked mainly by selective antagonist of M1 receptor, pirenzepine (PZ, 30 nmol/L, n = 9), but not by selective antagonist of M2 receptor, methoctramine (MT) and AFDX-116. The inhibitory effect of ACh (n = 10) could be blocked mostly by M2 receptor antagonist MT (30 nmol/L, n = 7); and this inhibitory effect (n = 9) could be blocked mostly by another M2 receptor antagonist AFDX-116 (30 nmol/L, n = 6), but not by M1 receptor antagonist PZ. 相似文献
4.
The data of nine children with post-traumatic intramural haematoma of the duodenum treated in Aghia Sophia Children's Hospital of Athens from 1967 to 1980 were retrospectively analysed. Diagnosis was preoperative in all but two children, in whom diagnosis was made during laparotomy. All but one were managed by operative intervention which consisted of simple evacuation of the haematoma and closure of the serosal incision in two out of eight children. Six out of eight children operated on were followed up for 15 years, during which they were free of symptoms. Hypotonic duodenography performed in the above patients was negative for deformity or stricture of the duodenum. 相似文献
5.
Qualitative urinalysis methods of monitoring cocaine use may over-detect frequency of use, possibly decreasing the ability of clinical trials to detect effective treatments. Quantitative urinalysis and newly developed criteria for identifying new cocaine use were evaluated as alternative measures of cocaine use. Urine specimens collected in a cocaine dosing study in non-treatment-seeking subjects (n = 5) and a cocaine treatment trial (n = 37) were analyzed for the cocaine metabolite, benzoylecgonine, with qualitative and quantitative methods. Pharmacokinetic criteria ('New Use' rules) were applied to quantitative data to identify occasions of new cocaine use. Results were compared to known cocaine administrations in the laboratory study and to self-reported drug use and qualitative urinalysis for subjects in the clinical trial. New Use criteria correctly identified cocaine administrations in the cocaine dosing study in all but a small number of specimens. In the clinical trial, quantitative urinalysis and estimated New Uses provided more information about patterns and frequency of use than qualitative urinalysis in the different treatment conditions in the clinical trial. Interpretation of quantitative urinalysis with New Use rules appears to be a useful method for monitoring treatment outcome and may be more accurate than traditional qualitative urinalysis in estimating frequency of cocaine use. 相似文献
6.
Analysis of some herbal plants from India used in the control of diabetes mellitus by NAA and AAS techniques 总被引:1,自引:0,他引:1
Elemental analysis of some herbal plants used in the control of diabetes has been done by the techniques of Neutron Activation Analysis (NAA) and Atomic Absorption Spectroscopy (AAS). The elements Mn, Na, K, Cl, Al, Cu, Co, Pb, Ni, Cr, Cd, Fe, Ca, Zn and Hg are found to be present in different plants in various proportions. 相似文献
7.
TJ Meyer SE Eveloff MS Bauer WA Schwartz NS Hill RP Millman 《Canadian Metallurgical Quarterly》1994,105(4):1211-1216
Sleep deprivation and fragmentation occurring in the hospital setting may have a negative impact on the respiratory system by decreasing respiratory muscle function and ventilatory response to CO2. Sleep deprivation in a patient with respiratory failure may, therefore, impair recovery and weaning from mechanical ventilation. We postulate that light, sound, and interruption levels in a weaning unit are major factors resulting in sleep disorders and possibly circadian rhythm disruption. As an initial test of this hypothesis, we sampled interruption levels and continuously monitored light and sound levels for a minimum of seven consecutive days in a medical ICU, a multiple bed respiratory care unit (RCU) room, a single-bed RCU room, and a private room. Light levels in all areas maintained a day-night rhythm, with peak levels dependent on window orientation and shading. Peak sound levels were extremely high in all areas representing values significantly higher than those recommended by the Environmental Protection Agency as acceptable for a hospital environment. The number of sound peaks greater than 80 decibels, which may result in sleep arousals, was especially high in the intensive and respiratory care areas, but did show a day-night rhythm in all settings. Patient interruptions tended to be erratic, leaving little time for condensed sleep. We conclude that the potential for environmentally induced sleep disruption is high in all areas, but especially high in the intensive and respiratory care areas where the negative consequences may be the most severe. 相似文献
8.
9.
10.
OM Takayanagui AA Castro e Silva RC Santiago NS Odashima VC Terra AM Takayanagui 《Canadian Metallurgical Quarterly》1996,54(4):557-564
Cysticercosis is a severe public health problem in several regions of Asia, Africa and Latin America. Epidemiologic studies based on the frequency of cases observed in specialized neurology, neurosurgery and computed tomography services, at autopsy and in seroepidemiologic studies do not permit the determination of the true prevalence of the disease in the population. The objective of the present study was to investigate the prevalence of cysticercosis by compulsory notification. The coefficient of prevalence was 54 cases/100,000 inhabitants in the municipality of Ribeir?o Preto. The results also indicated that cysticercosis is not under control in our region since 21% of cases presented the active form of the disease. Compulsory notification proved to be a valuable resource for the epidemiologic study of cysticercosis, also permitting the mapping of more affected areas for a better direction of prevention strategies. 相似文献