首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   789篇
  免费   1篇
  国内免费   3篇
化学工业   4篇
金属工艺   3篇
轻工业   1篇
一般工业技术   1篇
冶金工业   783篇
自动化技术   1篇
  2020年   1篇
  2019年   1篇
  2016年   1篇
  2011年   1篇
  2008年   1篇
  2003年   1篇
  1999年   19篇
  1998年   235篇
  1997年   153篇
  1996年   108篇
  1995年   46篇
  1994年   39篇
  1993年   36篇
  1992年   6篇
  1991年   11篇
  1990年   8篇
  1989年   12篇
  1988年   4篇
  1987年   3篇
  1986年   8篇
  1985年   7篇
  1983年   2篇
  1982年   3篇
  1981年   1篇
  1980年   9篇
  1978年   2篇
  1977年   20篇
  1976年   52篇
  1975年   1篇
  1972年   1篇
  1955年   1篇
排序方式: 共有793条查询结果,搜索用时 15 毫秒
61.
This study analyzes the severity of coronary artery disease in terms of the severity of renal artery disease in 609 patients undergoing coronary and renal angiography. The presence of renal artery disease of any severity is strongly suggestive of advanced coronary artery disease.  相似文献   
62.
Two previously healthy adults, a man aged 69 and a woman aged 51 years, presented with spondylitis caused by Streptococcus agalactiae. One patient had fever and acute pain in the neck, the other progressive pain in the lower back. From cultures of blood and bone respectively. S. agalactiae was isolated. Both patients recovered after treatment with benzylpenicillin. S. agalactiae (group B streptococcus) is a wellknown cause of invasive infections in neonates and pregnant adults. Infections in nonpregnant adults are increasingly reported. Chronic conditions such as diabetes mellitus are strongly associated with disease caused by S. agalactiae.  相似文献   
63.
Clinical requirements for calcium phosphate bone cements were formulated in terms of the initial setting time, the final setting time, the cohesion time and the ultimate compressive strength. Three cement formulations were tested. The previously developed Biocement H was made of a powder containing alpha-tertiary calcium phosphate and precipitated hydroxyapatite. Biocement B2 powder was made by adding some CaCO3 to Biocement H, whereas Biocement B1 was made by adding some CaCO3 but with simultaneous adjustment of the amount of precipitated hydroxyapatite.The liquid/ powder ratio of the cement paste and the accelerator concentrations (percentage Na2HPO4) in cement liquid were varied. For Biocement H there was no combination of L/P ratio and percentage Na2HPO4 for which all clinical requirements were satisfied. However, there was an area of full compliance for Biocements B1 and B2, of which that for B1 was the largest. Therefore, Biocement B1 may be applied in clinical situations as those in orthopaedics, plastic and reconstructive surgery and oral and maxillofacial surgery, even when early contact with blood is inevitable.  相似文献   
64.
Salvage of lower-extremity Gustilo type IIIC fractures is difficult, time-consuming for the patients and physicians, and not universally successful because of poor functional outcomes. Even if successful with limb salvage, the functional result may be unsatisfactory because of mutilating injuries to muscle and nerve, bone loss, and the presence of chronic infection. From July 1991 until July 1994, revascularizations of open IIIC fractures were attempted for wounds with Mangled Extremity Severity Score (MESS) < or = 10. The functional results were evaluated at 2 years after injury. Thirty-six lower-extremity revascularizations were performed on 34 patients, including 1 patient with bilateral distal tibial IIIC fractures and a child with IIIC femoral fracture accompanied by ipsilateral distal tibial amputation. Excluded were patients with below-ankle IIIC fractures as well as patients who underwent immediate amputation at admission. After the revascularization, seven patients with IIIC fractures (7 of 36, 19.4%) underwent secondary amputation within 1 week. At the 2-year follow-up, the overall secondary amputation rate was 25% (9 of 36) and the salvage rate was 75% (27 of 36). Those were no deaths. Of the 29 salvaged limbs among these 27 patients, 23 limbs (23 of 29, 79.3%) required secondary coverage procedures that included 12 free flap transfers (12 of 29, 41.4%). Every patient needed subsequent reconstructive surgery to achieve an acceptable functional result. In this series, MESS was able to predict the secondary amputation rate and the functional result. Sixteen of the 17 limb-salvaged patients with MESS < or = 7 were able to achieve minimal functional requirements, whereas 3 of the 10 patients with MESS = 8 to 10 failed to achieve minimal functional requirements at the 2-year follow-up. Using statistical analysis, we found that the salvaged limbs with MESS < or = 9 exhibited a significant difference in achieving adequate function compared with limbs with MESS > 9. Using our protocol for treatment for IIIC fractures, the threshold for immediate amputation can be raised from MESS = 7 to MESS = 9. Our conclusions are (1) more severely injured limbs have poor functional results, (2) every patient needs subsequent reconstructive surgery, and (3) the MESS may be helpful in decision-making.  相似文献   
65.
66.
67.
The presence of ochratoxin A (OA) in human milk samples from different regions in Norway was investigated to determine the level of infant exposure to OA from human milk. OA was found in 38 (33%) of 115 human milk samples (range 10-130 ng l(-1)). It was found that 2-26% of the samples contained more than 40 ng l(-1) OA, which will cause a daily intake of OA from human milk exceeding the suggested tolerable dose of 5 ng kg(-1) body weight. Significant regional differences were found.  相似文献   
68.
There is a growing need for immediately available material with appropriate qualities for reconstruction of large bone defects. Autologous spongy bone grafts are optimal as to biocompatibility, but are in short supply. Allogenic and xenogenic bone grafts evoke an immunological reaction after implantation and are not biocompatible. In the last thirty years ceramic implants and composites have been developed for bone substitution. New calcium phosphate bone substitutes undergo processes of resorption and precipitation of carbonate apatite that play a part in formation of new bone. These materials are easy to use because of their pastelike consistence. Resorption properties are influenced by particle size, crystallinity and composition. So far, no serious adverse reactions were reported. More clinical experience is necessary especially with composites and combinations with antibiotics, bone growth factors and collagen, to specify the place of these modern calcium phosphates in bone replacement and bone substitution.  相似文献   
69.
2-Amino (6), 2-alkylamino (7-8), 2-methoxy (9), 2-acetamido (10), and 5,8-diacetoxy (11) derivatives of the lead compound 2,3-dichloro-5,8-dimethoxy-1,4-naphthoquinone (4) were synthesized, together with 6,7-dichloro-5,8dimethoxy-1,4-naphthoquinone (5), a positional isomer of 4. Antiplatelet, antiinflammatory, and antiallergic activities were evaluated, and most compounds were quite potent in all assays. Compounds 5 and 9-11 were especially active; however, 5 was ineffective against neutrophil superoxide formation, and 10 was ineffective against mast cell degranulation.  相似文献   
70.
The wrist is a common site of injury in sports, both acute and chronic. Evaluation of wrist injuries requires knowledge of anatomy kinematics, attention to the mechanism of injury, the intensity of training, and a focus on the physical examination for specific injuries.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号