全文获取类型
收费全文 | 1634篇 |
免费 | 13篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 18篇 |
综合类 | 1篇 |
化学工业 | 138篇 |
金属工艺 | 17篇 |
机械仪表 | 18篇 |
建筑科学 | 22篇 |
矿业工程 | 4篇 |
能源动力 | 17篇 |
轻工业 | 63篇 |
水利工程 | 6篇 |
无线电 | 83篇 |
一般工业技术 | 127篇 |
冶金工业 | 1061篇 |
原子能技术 | 9篇 |
自动化技术 | 66篇 |
出版年
2024年 | 7篇 |
2023年 | 5篇 |
2021年 | 8篇 |
2020年 | 11篇 |
2019年 | 13篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 15篇 |
2015年 | 9篇 |
2014年 | 8篇 |
2013年 | 56篇 |
2012年 | 28篇 |
2011年 | 28篇 |
2010年 | 27篇 |
2009年 | 22篇 |
2008年 | 24篇 |
2007年 | 26篇 |
2006年 | 20篇 |
2005年 | 23篇 |
2004年 | 19篇 |
2003年 | 18篇 |
2002年 | 15篇 |
2001年 | 11篇 |
2000年 | 16篇 |
1999年 | 39篇 |
1998年 | 315篇 |
1997年 | 186篇 |
1996年 | 146篇 |
1995年 | 67篇 |
1994年 | 62篇 |
1993年 | 55篇 |
1992年 | 19篇 |
1991年 | 17篇 |
1990年 | 17篇 |
1989年 | 22篇 |
1988年 | 13篇 |
1987年 | 14篇 |
1986年 | 14篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 34篇 |
1976年 | 72篇 |
1975年 | 5篇 |
1972年 | 5篇 |
排序方式: 共有1650条查询结果,搜索用时 15 毫秒
71.
The immunosuppressive agent FK 506 is widely used in liver transplant patients. Neurotoxicity is a major complication of its use. We report progressive and irreversible neurologic complications occurring in a 39-year-old woman who underwent liver transplantation and was treated with FK 506. Neuropathologic examination revealed multiple vasculitic lesions. The possibility of an FK 506-mediated toxic effect on the cerebral vessels is suggested. 相似文献
72.
FC Blow KL Barry BJ BootsMiller LA Copeland R McCormick S Visnic 《Canadian Metallurgical Quarterly》1998,32(5):311-319
Within a fungal species, a subset of individuals may have more than the minimal complement of chromosomes. If the extra chromosomes are composed primarily of DNA not found in all representatives of the species, they are most appropriately referred to as supernumerary chromosomes. The patterns of repeated DNA sequences on certain supernumerary chromosomes suggest that they have a different evolutionary history from the essential chromosomes in the same genome. Supernumerary chromosomes can carry functional genes and, in at least two fungal species, genes on such chromosomes play important roles in host-pathogen interactions. Supernumerary chromosomes that confer an adaptive advantage in certain habitats, such as the ability to cause disease on a specific host, may be referred to as "conditionally dispensable" chromosomes in order to reflect their importance in some, but not all, growth conditions. In addition to describing the structural and functional characteristics of known supernumerary chromosomes in fungi, this review discusses the relative merits of the terms that have been used to describe them, and establishes experimental criteria for their identification. 相似文献
73.
74.
75.
76.
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
77.
78.
F Coulin CA Power S Alouani MC Peitsch JM Schroeder M Moshizuki I Clark-Lewis TN Wells 《Canadian Metallurgical Quarterly》1997,248(2):507-515
The aim of this study was to determine the level of endogenous prostaglandin E2 (PGE2), prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane B2 (TXB2) in the gastric and duodenal mucosa of patients with duodenal ulcer and duodenitis. Besides, the investigation aimed at determining the effect of smoking and infection by Helicobater pylori on prostaglandin synthesis. The investigation comprised 62 patients with duodenal ulcer, 46 patients with duodenitis and 44 controls. The results of our investigation indicate that the decreased prostaglandin synthesis in gastric and duodenal mucosa determined in patients with duodenal ulcer may have a considerable role in development of duodenal ulcer. Furthermore, the harmful effects of smoking on the gastric and duodenal mucosa may be mediated by the decreased prostaglandin synthesis in the gastric and duodenal mucosa. However, Helicobacter pylori seems to affect the development of duodenal ulcer through other mechanisms. 相似文献
79.
80.
CA Arndt AG Nascimento G Schroeder PJ Schomberg JP Neglia SF Sencer TL Silberman CL Moertel JK Tillisch JS Miser 《Canadian Metallurgical Quarterly》1998,34(8):1224-1229
Over 50% of patients with newly diagnosed rhabdomyosarcoma (RMS) are in the 'intermediate risk' group with a 3-year progression-free survival of approximately 65%. This group consists of stage 1, group III, non-orbit tumours; stage 2, group II and III; and all stage 3 patients utilising the Intergroup Rhabdomyosarcoma Study (IRS) staging system. The role of doxorubicin in the treatment of RMS has been controversial. Ifosfamide, both alone and in combination with etoposide, has significant activity in patients with RMS. The aim of this pilot study was to examine the efficacy and toxicity of a chemotherapy regimen of alternating cycles of vincristine/doxorubicin/cyclophosphamide and etoposide/ifosfamide for intermediate risk RMS. 30 patients with intermediate risk RMS or undifferentiated sarcoma (US) were treated with alternating cycles of vincristine/doxorubicin/cyclophosphamide (VDC) and etoposide/ifosfamide (EI) at planned intervals of 3 weeks. Local treatment of the tumour in most cases was performed after four cycles of chemotherapy, followed by an additional 10 cycles of chemotherapy. At a median follow-up of 37.5 months, the Kaplan-Meier estimate of 3-year event-free survival was 85% (95% confidence interval 72-99%). The overall survival at 3 years was 91% (95% confidence interval 80-100%). No patient died from toxicity. The most common toxicity was febrile neutropenia in 35% of VDC and 26% of EI cycles. No nephrotoxicity or cardiac toxicity was seen. No patient progressed prior to week 12 local therapy. Alternating cycles of VDC and EI are an effective treatment for patients with intermediate risk RMS and US. Toxicity is tolerable. Delaying local treatment until week 12 does not compromise outcome. 相似文献