全文获取类型
收费全文 | 4702篇 |
免费 | 10篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 56篇 |
金属工艺 | 24篇 |
机械仪表 | 8篇 |
建筑科学 | 18篇 |
能源动力 | 10篇 |
轻工业 | 75篇 |
水利工程 | 4篇 |
无线电 | 44篇 |
一般工业技术 | 63篇 |
冶金工业 | 4366篇 |
原子能技术 | 2篇 |
自动化技术 | 39篇 |
出版年
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 17篇 |
2012年 | 8篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 16篇 |
2008年 | 29篇 |
2007年 | 20篇 |
2006年 | 13篇 |
2005年 | 18篇 |
2004年 | 20篇 |
2003年 | 17篇 |
2002年 | 18篇 |
2001年 | 14篇 |
2000年 | 6篇 |
1999年 | 143篇 |
1998年 | 1442篇 |
1997年 | 803篇 |
1996年 | 526篇 |
1995年 | 269篇 |
1994年 | 238篇 |
1993年 | 262篇 |
1992年 | 36篇 |
1991年 | 45篇 |
1990年 | 40篇 |
1989年 | 53篇 |
1988年 | 59篇 |
1987年 | 30篇 |
1986年 | 34篇 |
1985年 | 35篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 17篇 |
1981年 | 20篇 |
1980年 | 51篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 92篇 |
1976年 | 196篇 |
1975年 | 12篇 |
1974年 | 5篇 |
1973年 | 6篇 |
1972年 | 2篇 |
1970年 | 6篇 |
排序方式: 共有4712条查询结果,搜索用时 0 毫秒
971.
972.
973.
974.
975.
E Koss MB Patterson R Ownby JC Stuckey PJ Whitehouse 《Canadian Metallurgical Quarterly》1993,50(1):92-97
OBJECTIVES: To evaluate if caregivers are reliable informants concerning memory deficits in patients with Alzheimer's disease (AD). DESIGN: Responses of caregivers of patients with probable AD and responses of healthy control subjects on a standardized memory questionnaire were compared with objective measures of cognition (Consortium to Establish a Registry for Alzheimer's Disease neuropsychological battery) and with clinical estimates of activities of daily living, depression, and psychopathology (Consortium to Establish a Registry for Alzheimer's Disease [CERAD] clinical assessment battery) using the Self-report Memory Questionnaire. SETTING: A federally funded AD research center. SUBJECTS: The referred sample included 117 patients with probable AD, their informants, and 41 healthy control subjects age-matched to the patients. Patients and control subjects were between the ages of 58 and 85 years, had between 9 and 19 years of education, and were in good health. EXCLUSIONS: Patients who did not meet NINCDS-ADRDA criteria of probable AD. MAIN OUTCOME MEASURE: The optimal number of questionnaire items yielding the best combination of sensitivity and specificity. RESULTS: An abbreviated version of the scale, renamed the Short-Memory Questionnaire, had excellent specificity and sensitivity for identifying dementia. Positive and negative predictive values were 63.5% and near 100%, respectively. The Short-Memory Questionnaire showed good reliability, internal consistency, and external validity. Caregiver appraisals of memory deficits significantly correlated with objective measures of memory and also with generalized cognitive dysfunction. CONCLUSIONS: Caregivers of patients with AD are reliable informants of their relatives' deficits. The Short-Memory Questionnaire is an easily administered, informant-based scale that may be useful in clinical settings or epidemiologic studies to screen out persons with memory difficulties. 相似文献
976.
K Nakayama K Nakayama I Negishi K Kuida Y Shinkai MC Louie LE Fields PJ Lucas V Stewart FW Alt 《Canadian Metallurgical Quarterly》1993,261(5128):1584-1588
The bcl-2 proto-oncogene can prevent the death of many cell types. Mice were generated that were chimeric for the homozygous inactivation of bcl-2. Lymphocytes without Bcl-2 differentiated into phenotypically mature cells. However, in vitro, the mature T cells that lacked Bcl-2 had shorter life-spans and increased sensitivity to glucocorticoids and gamma-irradiation. In contrast, stimulation of CD3 inhibited the death of these cells. T and B cells with no Bcl-2 disappeared from the bone marrow, thymus, and periphery by 4 weeks of age. Thus, Bcl-2 was dispensable for lymphocyte maturation, but was required for a stable immune system after birth. 相似文献
977.
We report on a project to assist victims of war and violence in Uganda. The original aim of this project, set up by the Medical Foundation for the Care of Victims of Torture, was to establish a centre for the assessment and treatment of torture victims who had suffered during previous regimes in that country. We found, however, that a specialist centre was not the most appropriate response in a country like Uganda. We argue for the need to respect local initiatives and systems of support and against the notion that there is a single model of care which is universally relevant. Following much investigation and involvement with local personnel, we have developed a programme of training and discussion for health workers, and a service to reach the many women who have suffered rape, and whose suffering has continued, largely ignored. 相似文献
978.
979.
MG Hunter L Bawden D Brotherton S Craig S Cribbes LG Czaplewski TM Dexter AH Drummond AH Gearing CM Heyworth BI Lord M McCourt PG Varley LM Wood RM Edwards PJ Lewis 《Canadian Metallurgical Quarterly》1995,86(12):4400-4408
The stem cell inhibitor, macrophage inflammatory protein-1 alpha (MIP-1 alpha) or LD78, protects multipotent hematopoietic progenitors in murine models from the cytotoxic effects of chemotherapy. Clinical use of human MIP-1 alpha during chemotherapy could therefore lead to faster hematologic recovery and may allow dose intensification. We have also shown that human MIP-1 alpha causes the rapid mobilization of hematopoietic cells, suggesting an additional clinical use in peripheral blood stem cell transplantation. However, the clinical evaluation of human MIP-1 alpha is complicated by its tendency to associate and form high molecular weight polymers. We have produced a variant of rhMIP-1 alpha, BB-10010, carrying a single amino acid substitution of Asp26 > Ala, with a reduced tendency to form large polymers at physiologic pH and ionic strength. This greatly increases its solubility, facilitating its production and clinical formulation. We confirmed the potency of BB-10010 as a human MIP-1 alpha-like agonist in receptor binding, calcium mobilization, inhibition of colony formation, and thymidine suicide assays. The myeloprotective activity of BB-10010 was shown in a murine model of repeated chemotherapy using hydroxyurea. BB-10010 is therefore an ideal variant with which to evaluate the therapeutic potential of recombinant human MIP-1 alpha. 相似文献
980.