全文获取类型
收费全文 | 2699篇 |
免费 | 4篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 127篇 |
金属工艺 | 14篇 |
机械仪表 | 23篇 |
建筑科学 | 23篇 |
能源动力 | 23篇 |
轻工业 | 31篇 |
水利工程 | 7篇 |
无线电 | 28篇 |
一般工业技术 | 92篇 |
冶金工业 | 2275篇 |
原子能技术 | 3篇 |
自动化技术 | 52篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2014年 | 9篇 |
2013年 | 46篇 |
2012年 | 12篇 |
2011年 | 13篇 |
2010年 | 17篇 |
2009年 | 14篇 |
2008年 | 17篇 |
2007年 | 17篇 |
2006年 | 15篇 |
2005年 | 10篇 |
2004年 | 8篇 |
2003年 | 24篇 |
2002年 | 10篇 |
2001年 | 7篇 |
2000年 | 13篇 |
1999年 | 104篇 |
1998年 | 720篇 |
1997年 | 402篇 |
1996年 | 271篇 |
1995年 | 147篇 |
1994年 | 137篇 |
1993年 | 149篇 |
1992年 | 21篇 |
1991年 | 30篇 |
1990年 | 32篇 |
1989年 | 29篇 |
1988年 | 31篇 |
1987年 | 9篇 |
1986年 | 15篇 |
1985年 | 21篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 22篇 |
1979年 | 8篇 |
1978年 | 13篇 |
1977年 | 49篇 |
1976年 | 122篇 |
1975年 | 5篇 |
1974年 | 9篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1970年 | 12篇 |
1969年 | 3篇 |
排序方式: 共有2703条查询结果,搜索用时 15 毫秒
91.
92.
Presents a lecture delivered at the 1980 meeting of the Canadian Psychological Association. The present status of behavior genetics is reviewed. The nature-nurture issue is considered, and research on the genetic–environment interaction is advocated. Many hybrid sciences use reductionism to explain the phenomena of complex systems by the principles of the more basic sciences that deal with the component parts of these systems. A reductionistic view of behavior genetics is rejected; instead, the author prefers an approach that examines how biological factors directly influence behavior. Current trends in behavior genetics are identified. (French abstract) (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
93.
1. The effects of histamine on gastric mucosal blood flow in the presence and absence of gastric acid secretion were studied in the rat. 2. Histamine, in doses greater than those required to stimulate maximal acid secretion, caused a small increase in mucosal blood flow per unit acid output. 3. When acid secretion was inhibited by methyl analogues of prostaglandin E2, histamine reduced arterial blood pressure and gave a dose dependent rise in mucosal blood flow. 4. When acid secretion was inhibited by the histamine H2-receptor antagonists, burimamide and metiamide, histamine still increased mucosal blood flow. 5. The use of H1-receptor antagonists to inhibit the histamine-induced hyperaemia was made difficult by their vasodilator actions. 6. The selective histamine H2-receptor agonist, 4-methyl histamine, had no effect on arterial blood pressure in doses which stimulated acid secretion. The increase in mucosal blood flow which accompanied the stimulation of acid secretion was inhibited by the anti-secretory prostaglandins and H2-receptor antagonists. 7. The selective histamine H1-receptor agonist, 2-pyridyl ethylamine, had no effect on acid output but increased resting mucosal blood flow. 8. These results suggest that histamine H2-receptors, primarily concerned with acid secretion, and H1-receptors concerned with vasodilatation are both present in the rat gastric mucosa. 相似文献
94.
The effect of cetylpyridinium chloride (CPC) on pathogenic fungi and Nocardia asteroides was studied. Sputa seeded with each of 11 organisms (Aspergillus flavus; Aspergillus fumigatus, Blastomyces dermatitidis, Candida albicans, Coccidioides immitis, Cryptococcus neoformans, Geotrichum candidum, Histoplasma capsulatum; Nocardia asteroides, Paracoccidioides brasiliensis, and Sporothrix schenckii) were treated with CPC and kept for 2, 5 and 9 days. The CPC reagent used (0.5% CPC and 0.5% sodium chloride) is one the Mycobacteriolgoy Branch at the Center for Disease Control added to sputa before shipping them to laboratories for recovery of mycobacteria. None of the organisms tested survived this treatment, and none was recovered on mycological or mycobacteriological media. Seeded sputa containing these organisms were also tested with a second CPC reagent (0.02% CPC and 0.5% sodium chloride) and held for 2, 5 and 9 days. A few colonies of A. flavus, A. fumigatus, and N. asteroides were recovered from these samples. Neither the morphology of the fungi nor their stainability by the fluorescent antibody method was affected by treatment with the reagent containing 0.5% CPC. However, the background material in smears from the 0.5% CPC-treated samples retained the conjugate, and this made weakly fluorescing organisms more difficult to detect. The 0.5% CPC treatment did not alter the morphology of N. asteroides or its ability to be stained with Kinyoun acid-fast stain. 相似文献
95.
After presenting the topographical and pathological basis for the habitual luxation of the shoulder joint, our experience with the Bankart-Müller operation on 38 of our own patients was described. The results are characterized as very good, particularly two years and longer after the operation. 相似文献
96.
The localization of soluble, cercarial antigen preparation (CAP) in cercariae and schistosomules of Schistosoma mansoni was performed at the light and electron microscope levels using the unlabeled antibody method. Reaction produce was observed associated with the contents of the pre- and postacetabular glands and with the filamentous coat of mature cercariae. No reaction product was observed associated with the glycoacalyx of schistosomules. However, several schistosomules did retain remnants of their filamentous coats and reaction product was observed associated with those remains. CAP components were also observed in the area surrounding the intrasporocyst cercariae. 相似文献
97.
98.
99.
100.
M. J. Diamond H. L. Needles C. A. Elliger D. J. Kertesz E. N. Frankel G. Fuller 《Journal of the American Oil Chemists' Society》1971,48(11):678-681
Two synthetic routes were followed to prepare graft copolymers with long side chains containing acyl chloride terminal groups.
In the first of these methods acryloxy aliphatic acyl chlorides were synthesized from ricinoleic acid, 12-hydroxystearic acid
and 10-hydroxydecanoic acid and then polymerized with other acrylate ester comonomers. In the second procedure, a prepolymer
was formed by copolymerizing acryloyl chloride with acrylate esters. The prepolymer then was treated with 12-hydroxystearic
acid or 9(10)-hydroxymethylstearic acid to produce polymers with side chains having terminal carboxylic acid groups. These
polymers were made more reactive by conversion to acid chlorides. The active polymers were applied to wool fabrics; the imparted
shrink-resistance was durable under an accelerated wash test procedure. An added advantage of the treatment is a soft “hand”
or feel resulting from internal plasticization of the polymer coating.
No. Market. Nutr. Res. Div., ARS, USDA.
W. Market, Nutr. Res. Div. ARS, USDA. 相似文献