全文获取类型
收费全文 | 1614篇 |
免费 | 1篇 |
专业分类
化学工业 | 7篇 |
建筑科学 | 1篇 |
轻工业 | 4篇 |
一般工业技术 | 8篇 |
冶金工业 | 1592篇 |
自动化技术 | 3篇 |
出版年
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1999年 | 48篇 |
1998年 | 484篇 |
1997年 | 266篇 |
1996年 | 201篇 |
1995年 | 94篇 |
1994年 | 78篇 |
1993年 | 98篇 |
1992年 | 15篇 |
1991年 | 21篇 |
1990年 | 22篇 |
1989年 | 23篇 |
1988年 | 22篇 |
1987年 | 43篇 |
1986年 | 24篇 |
1985年 | 28篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1978年 | 1篇 |
1977年 | 31篇 |
1976年 | 68篇 |
1955年 | 1篇 |
排序方式: 共有1615条查询结果,搜索用时 15 毫秒
951.
Large numbers of a reovirus-like agent were visualized with electron microscopy in bacteria-free gut homogenates obtained from piglets with a fatal diarrhea resembling transmissible gastroenteritis. The syndrome, of vomiting, diarrhea, dehydration, and death, was reproduced in piglets artificially infected with these bacteria-free gut homogenates. Reovirus-like particles persisted in serial piglet passage and none was seen in uninfected, asymptomatic controls. Hyperimmune sera (made in recovered piglets) aggregated the reovirus-like particles, as judged by immunoelectron microscopy, and neutralized the infectious agent. The cytoplasm in enterocytes on infected intestinal epithelium fluoresced when this hyperimmune sera was used in an indirect fluorescent antibody test. Feeding cow colostrum or diets containing porcine gamma globulin protected infected piglets. No cytopathogenic effect was noted in infected tissue cultures, nor did this agent affect neonatal guinea pigs, hamsters, mice, and rats. The agent did not agglutinate human O or A erythrocytes. 相似文献
952.
Acute capture myopathy was diagnosed in 3 elk (Cervus canadensis). In 2 of the elk, hindlimb lameness developed within 10 days of capture. Clinical signs were not observed in the third elk, which was found dead 7 days after its capture. Elks 1 and 2 were euthanatized and all 3 animals were necropsied. In elks 1 and 2, rupture of the semi-membranosus muscle was associated with massive hemorrhage and swelling. Microscopic findings included hemorrhage, edema, myofibril fragmentation, and evidence of attempted muscular regeneration. In elk 3, several of the large muscles of the hindlimbs as well as the biceps brachii muscles of the forelimbs appeared pale, dry, and friable. Except for lack of hemorrhage and edema, microscopic findings in this elk were similar to those of elks 1 and 2. 相似文献
953.
954.
1. Plasma ADH concentration, urinary and plasma osmolality and haematocrit were measured in young pigs placed in cold, thermoneutral, warm and hot ambient temperatures. In some experiments a thermode placed in the hypothalamus or over the cervical spinal cord was heated or cooled at various ambient temperatures. 2. Plasma ADH concentration remained at a low level (0-5--5 muu. ml.-1) over 2 hr or 3 hr periods when the pigs were in cold, thermoneutral or warm ambient temperatures. A hot environment, which caused a marked rise in the pigs' rectal temperature, was associated with a large rise in plasma ADH level. 3. The rise in plasma ADH level which occurred during an increase in body temperature was consistently and completely suppressed by simultaneous cooling of the thermode in the pre-optic region to 5 to 10 degrees C. When the thermode was in the region of the supraoptic nucleus the rise in ADH was only partly suppressed, and when it was over the cervical cord it was only sometimes suppressed. 4. Cooling the thermodes in any position at a cold or thermoneutral ambient temperature, or heating them at a thermoneutral or warm ambient temperature, caused no consistent change in ADH. 5. A diuresis, with a urinary flow-rate of at most 1 ml. min-1 and minimal urinary osmolality of 53 m-osmole kg-1, was observed on only three occasions, twice during cooling of a thermode in the hypothalamus and once after the end of a period when the thermode was heated. In each case, the plasma ADH was less than 2 muu. ml.-1. 6. A slight rise of haematocrit in cold ambient conditions and a slight fall in the warm were observed. Otherwise changes in haematocrit were trivial, and a shift of water between vascular system and interstitium could not be invoked to account for changes in ADH levels. Observed variation of plasma osmolality was also slight. 相似文献
955.
956.
957.
Forty-five patients receiving renal allografts were gradually converted from daily to alternate-day prednisone therapy. Indications for conversion included aseptic necrosis, growth retardation in children and adolescents, obesity, diabetes, cataract formation, and cosmetic appearance. Eight of the 45 patients developed acute or chronic rejection during or just after completion of alternate-day steroid therapy. The remaining 37 patients had a notable decrease in the degree of hypercorticism, with return of growth in children and adolescents. However, there was no improvement once aseptic necrosis or cataract formation had occurred. Although the use of alternate-day prednisone therapy is of benefit in reducing the untoward side effects of corticosteroids, the risk of precipitating allograft rejection is a significant threat and must be carefully considered whenever this form of treatment is undertaken. 相似文献
958.
MW Dunstone 《Canadian Metallurgical Quarterly》1976,5(4):479-480
The Royal Australian College of General Practitioners, in association with Intercontinental Medical Statistics conducted a General Practice Morbidity and Prescribing Survey from 1.4.69 to 31.12.74. This gave a baseline study of morbidity as it occurs in Australia plus a breakdown by State, sex, age and season, to give a clearer idea of geographical, personal and epidemiological factors influencing health and sickness. 相似文献
959.
960.