全文获取类型
收费全文 | 2515篇 |
免费 | 0篇 |
专业分类
化学工业 | 6篇 |
金属工艺 | 1篇 |
机械仪表 | 1篇 |
轻工业 | 1篇 |
无线电 | 6篇 |
一般工业技术 | 6篇 |
冶金工业 | 2473篇 |
原子能技术 | 4篇 |
自动化技术 | 17篇 |
出版年
2022年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2014年 | 2篇 |
2013年 | 3篇 |
2010年 | 2篇 |
2008年 | 3篇 |
2006年 | 2篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 58篇 |
1998年 | 773篇 |
1997年 | 459篇 |
1996年 | 273篇 |
1995年 | 185篇 |
1994年 | 101篇 |
1993年 | 151篇 |
1992年 | 19篇 |
1991年 | 26篇 |
1990年 | 21篇 |
1989年 | 18篇 |
1988年 | 23篇 |
1987年 | 29篇 |
1986年 | 15篇 |
1985年 | 13篇 |
1984年 | 1篇 |
1983年 | 6篇 |
1982年 | 10篇 |
1981年 | 28篇 |
1980年 | 19篇 |
1978年 | 4篇 |
1977年 | 87篇 |
1976年 | 158篇 |
1975年 | 6篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有2515条查询结果,搜索用时 15 毫秒
81.
82.
Endocrine and reproductive alterations are frequently reported to occur in women with temporal lobe epilepsy as well as in female rats in different experimental models of limbic seizures. As previously reported, women with epilepsy have lower fertility rates than women without epilepsy (Tanganelli, P., Regesta, G., 1992. Neurology (suppl.) 42 (5), 89-93; Cummings, L.N., Guidice, L., Morrel, M.J., 1995. Epilepsia 36, 355-359). In order to investigate the possible substrate of endocrine alterations in epilepsy, hormonal and gestational parameters were studied in female rats submitted to the pilocarpine model of epilepsy. The results demonstrated that the oestrus cycle is altered following pilocarpine-induced status epilepticus and such alteration lasted for several weeks. Progesterone, LH and FSH levels decreased and estradiol levels increased significantly during the period of spontaneous and recurrent seizures. The frequency of seizures during pregnancy and lactation decreased. These results document that significant changes in gonadal, hypophyseal and hypothalamic hormones, as well as in sexual behaviour, occur following status epilepticus induced by pilocarpine administration. 相似文献
83.
We studied the efficacy and feasibility of using computer-based instruction to provide medication information to hospitalized patients with acute psychotic conditions. Patients were randomly assigned to receive computer-based (n = 21) or personal instruction (n = 21); for the final analyses the computer group was expanded to include 13 patients from a pilot study. Outcome measures were knowledge retention (indicated by changes in test scores) and compliance with medication regimens after discharge (indicated by telephone follow-up at one week, one month, and three months). The subjects reacted positively to the computer program. Knowledge retention and compliance were similar in the computer and control groups. We conclude that psychiatric inpatients admitted for acute care can participate in, and learn from, computerized medication instruction. 相似文献
84.
An ongoing goal of aesthetic surgery is a reduction in complications and an improvement in reproducibility and speed. Balloon dissector devices have been used in other areas of surgery to achieve these goals. This report presents early clinical experience using a balloon dissector to elevate the skin flap in facialplasty. The first step in the technique is the creation of a tunnel from a small preauricular incision toward the oral commissure using scissors dissection. The balloon device is inserted into this tunnel and inflated. Unrolling the device elevates the skin flap in the cheek and neck area. Retroauricular dissection and final adjustment of flap size and shape is completed sharply. Subsequent superficial musculoaponeurotic system flap development, skin redraping, and closure is performed in a conventional fashion after customary facialplasty incisions are made. Comparison of complications, postoperative drainage, and time required for dissection and for hemostasis was made between a balloon-dissected side and a conventionally dissected side in 10 patients undergoing facialplasty. Ten additional patients were treated with balloon dissection bilaterally. Patients ranged in age from 45 to 73 years. Mean balloon dissection time was 1.4 minutes (range, 0.75-4 minutes). This produced an even flap thickness in the correct plane with few if any bleeding points. Mean total dissection time on the balloon side was significantly shorter-13.6 minutes-compared with 27.8 minutes (p < 0.003) on the conventional side. Mean difference in time to hemostasis between conventional and balloon sides was 3.8 minutes (p < 0.001). Mean total postoperative drainage (all drains removed at 24 hours) was 13.8 cc on the balloon side and 18.8 cc on the conventional side (not significant, p=0.08). Less ecchymosis and swelling was observed on the balloon side compared with the scissors-dissected side. There were no skin losses, hematomas, infections, or nerve injuries on either side. Appearance of skin redraping was comparable on each side in all patients. Balloon dissection represents a promising alternative means of creating rapid, reproducible skin flap elevation in facialplasty, and is associated with a minimum of bleeding, ecchymosis, and swelling. 相似文献
85.
The folic acid antagonists, methotrexate and aminopterin, are known to be teratogenic in humans. The critical period for their teratogenecity is suspected to be between 6 to 8 weeks post-conception. Fetal exposure from 10 to 32 weeks weeks post-conception to methotrexate alone or in combination with other anti-cancer drugs has not resulted in obvious teratogenic effects. Methotrexate is often used to treat cancers but is occasionally used as an abortifacient. The long-term outcome of the fetal aminopterin syndrome has been published in only four adults. We report on a 28-year-old man with fetal methotrexate syndrome and two children with mild manifestations of the syndrome. One child was inadvertently exposed to methotrexate from 7 1/2 through 30 weeks post-conception because his mother was receiving it for treatment of breast cancer. The other was exposed from 11 weeks and 5 days through 25 weeks in an attempt to induce abortion. The 28-year-old man has craniofacial and digital anomalies, growth retardation but normal intelligence as noted in the previously reported cases. These cases remind us of the teratogenicity of methotrexate and should serve as a warning that if methotrexate is used as an abortifaciant and an abortion does not ensue, there is a teratogenic risk. 相似文献
86.
Expression/induction of the 72 and 60 kDa heat shock proteins (HSPS 72 and 60) in cultured human keratinocytes by high calcium was studied with immunofluorescent staining and the flow cytometric method. Normal human keratinocytes cultured in serum free, low calcium medium (Ca2+, 0.1 mM) at 3-passage weakly expressed HSP 60, but not HSP 72, as fine granules in the cytoplasm. HSP 72 was induced in the perinuclear cytosomal area and then in the nucleus after transferring the cells in high calcium medium (Ca2+, 1.8 mM). Whereas the nuclear accumulation began to decrease 24 h after the treatment, the perinuclear cytosomal staining continued. High calcium also augmented the expression of HSP 60 as coarse granules in the cytoplasm. Flow cytometric analyses quantitatively revealed the induction of HSP 72 and the upregulation of HSP 60 by high calcium treatment. Our results clearly demonstrated that extracellular calcium concentration modifies the level of expression of HSP 72 and 60 in normal human keratinocytes, indicating the importance of the careful attention to medium condition in evaluating the expression of HSPS 72 and 60 in cultured keratinocytes. 相似文献
87.
EA Sickles 《Canadian Metallurgical Quarterly》1998,339(8):561-2; author reply 563
88.
89.
EA Tovar 《Canadian Metallurgical Quarterly》1998,116(2):371-372
90.