全文获取类型
收费全文 | 936篇 |
免费 | 0篇 |
专业分类
化学工业 | 4篇 |
建筑科学 | 3篇 |
能源动力 | 1篇 |
轻工业 | 6篇 |
冶金工业 | 920篇 |
自动化技术 | 2篇 |
出版年
2020年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2007年 | 2篇 |
2005年 | 1篇 |
2004年 | 1篇 |
1999年 | 21篇 |
1998年 | 303篇 |
1997年 | 147篇 |
1996年 | 111篇 |
1995年 | 67篇 |
1994年 | 52篇 |
1993年 | 39篇 |
1992年 | 6篇 |
1991年 | 16篇 |
1990年 | 21篇 |
1989年 | 24篇 |
1988年 | 29篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 5篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1978年 | 1篇 |
1977年 | 12篇 |
1976年 | 28篇 |
1964年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有936条查询结果,搜索用时 15 毫秒
61.
62.
DM Brienza KC Chung CE Brubaker J Wang TE Karg CT Lin 《Canadian Metallurgical Quarterly》1996,4(2):103-113
Chronic aspiration in the neurologically impaired child is associated with significant medical and social complications. Traditional surgical management has often relied on tracheotomy. This may well fail to control aspiration. The purpose of this retrospective study was to determine which neurologically impaired children would benefit from a laryngotracheal separation (LTS), as opposed to tracheotomy, as the primary surgical procedure to control chronic salivary aspiration. Patient selection was based on neurologic status, verbal communication ability, likelihood of neurologic recovery, and failure of previous treatments to control aspiration. Nineteen neurologically impaired children aged 8-172 months with chronic salivary aspiration underwent LTS. A total of 73.6% of these patients had prior tracheotomies, yet they continued to aspirate. Two early and three late complications were noted. No instances of fistula formation were noted. There were no deaths related to complications of the surgery or persistent aspiration. Follow-up 1-62 months after surgery demonstrated that complete control of the aspiration was achieved in all of these children. Two of the children who had achieved verbal communication prior to the procedure lost this ability. Improved general health and ability to resume oral intake was noted in all patients. This, combined with a decrease in the need of frequent suctioning, was felt by the families of these children to be a major improvement in the quality of life. Laryngotracheal separation appears to be a simple and effective means of controlling chronic aspiration. It should be considered as a primary treatment of aspiration in the properly selected child with neurologic disease. 相似文献
63.
64.
65.
A urinoma is a mass formed by encapsulated extravasated urine. It may follow closed renal injury, surgical operation or arise spontaneously in the presence of obstruction. The essential factors are continued renal function, rupture of the collecting system and distal obstruction. The extravasating urine is localised within the perirenal fascia and stimulates an intense fibrous reaction which forms a thick wall. Early diagnosis is important for successful treatment. The clinical features include malaise, vague abdominal pain, weight loss and a palpable mass. Plain films usually reveal a mass with loss of the retroperitoneal landmarks. High-dose excretion urography usually shows renal displacement, hydronephrosis and extravasation of contrast medium into the urinoma. Should renal function be inadequate for diagnosis, renal puncture, preceded by ultrasound examination, is the investigation of choice. 相似文献
66.
Severe combined immunodeficiency with cartilage-hair hypoplasa: in vitro response to thymosin and attempted reconstitution 总被引:1,自引:0,他引:1
The present report describes an infant with severe combined immunodeficiency and cartilage-hair hypoplasia whose lymphocytes responded to thymosin in vitro. Immunologic evaluation was undertaken at 4 1/2 months of age following a history of recurrent severe infection. Family history included three cousins who died in early infancy, one from streptococcal meningitis and pneumonia, one from generalized varicella, and another from reticuloendotheliosis. Quantitative immunoglobulins were markedly depressed: IgG 141, IgA 0, and IgM 24 mg/100 ml. There was an absolute lymphopenia, multiple skin tests were negative, and in vitro lymphocyte responses to mitogens and antigens were depressed. Spontaneous E rosette determinations were 21% compared with control values of 65.7%. Erythrocyte adenosine deaminase (ADA) activity was normal. The patient's E rosette formation increased in the presence of thymosin, fraction 5, reaching a maximum of 56% with a concentration of 500 mug thymosin. Blastogenic responses to phytohemagglutinin also increased in the presence of thymosin. Transplantation of 24-week fetal thymus in Millipore diffusion chambers and subsequently transplantation of 18-week fetal thymus by intraperitoneal injection was accomplished. E rosettes increased to 35-40% and blastogenic responses to mitogens increased. Eight days after the second transplant the patient underwent a mild graft vs. host reaction which subsided after 1 week and mitogen blastogenic responses again increased to 5-8 times previous values, but still well below control ranges. Repeated episodes of pulmonary infection ensued, cor pulmonale resulted, and the clinical course was relentlessly downhill with the patient expiring from respiratory failure 5 months after transplantation. 相似文献
67.
Venous angioma of the brain is a rare congenital vascular anomaly. In the last few years there have been several reports on the angiographic appearance of this lesion, but very little has been written about the findings on computed tomography (CT). Angiographically, the arterial phase is normal, while the capillary phase might demonstrate a blush. The major abnormality is the venous phase, where multiple dilated medullary veins converge centrally into a large drainage vein. The two cases presented here correlate the angiographic and CT appearances. It is felt that, with a knowledge of these findings, an accurate diagnosis of this condition can usually be reached. 相似文献
68.
The activity of a new photosensitizer, mono-L-aspartyl chlorin e6 (Npe6), was assessed in an ascending dose Phase I study for patients with superficial tumor. Eleven patients, with a total of 14 tumor sites, were treated with photodynamic therapy (PDT) using Npe6. Lesions included recurrent adenocarcinoma of the breast, basal cell carcinoma, and squamous cell carcinoma. The phototherapy protocol consisted of a single i.v. injection of 0.5-3.5 mg/kg Npe6, followed 4 h later by 25-100 j/cm2 at 664 nm of light. PDT using Npe6 caused no significant toxicity with the exception of temporary generalized skin photosensitivity. In all cases, light treatment caused immediate tissue blanching, followed by a marked necrosis of the tumor mass. Regression of tumor occurred over 24-48 h after the light treatment and was followed by the formation of a heavy eschar over the tumor site. Tumor regression was short-lived at Npe6 doses of 1.65 mg/kg and below. In two of three patients, tumor regression was either incomplete or tumors recurred within the 12-week observation period. Increasing the Npe6 dose to 2.5 or 3.5 mg/kg combined with 100 J/cm2 of light energy resulted in better control of tumor regrowth with 66% (6/9) of sites remaining tumor-free through 12 weeks observation. This increased tumor response came at the expense of the tissue selectivity observed at Npe6 doses of 1.65 mg/kg and below. There was no apparent selectivity for destruction of tumor compared with normal skin at Npe6 doses of 2.5 mg/kg and above. These data demonstrate that Npe6 is both an effective and safe photosensitizer for use in PDT and provide the impetus for continued study in Phase II clinical trials. 相似文献
69.
An in vitro foetal intestinal organ culture system was employed to determine the permissiveness of human intestinal cells for subgroup F adenovirus infection. Ad40 and Ad41 growth, monitored through group-specific hexon antigen production, was poor in comparison to that of Ad2 in these cultures, further demonstrating their fastidious nature in most human cells. The low growth capability of these viruses in culture, in relation to their association with gastrointestinal disease is discussed. 相似文献
70.
The purpose of this study was to determine if the sequence and interval between electric pulp testing and cold vitality testing with dichlorodifluoromethane affects the reliability of pulpal diagnostic testing. Sixty vital teeth in 15 volunteers were tested. Ten endodontically treated teeth were used as negative controls. After isolation and asepsis techniques, baseline threshold responses from a digital electric pulp tester were recorded from the maxillary incisors. A dichlorodifluoromethane-saturated cotton pellet was applied to teeth 8, 9, and 10. Electric pulp testing was repeated at 30-s, 1-min, and 2-min intervals on all test teeth after the cold test. The level of responses were recorded and statistically analyzed. The results of this study indicate that electric pulp testing is not adversely affected by the use of dichlorodifluoromethane. 相似文献