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   156篇
  免费   2篇
化学工业   9篇
机械仪表   2篇
建筑科学   1篇
轻工业   1篇
无线电   2篇
一般工业技术   6篇
冶金工业   123篇
原子能技术   14篇
  2019年   1篇
  2018年   1篇
  2015年   2篇
  2013年   1篇
  2012年   3篇
  2011年   1篇
  2010年   1篇
  2009年   2篇
  2008年   3篇
  2007年   1篇
  2006年   1篇
  2005年   4篇
  2004年   1篇
  2003年   1篇
  2002年   1篇
  2000年   1篇
  1999年   6篇
  1998年   32篇
  1997年   26篇
  1996年   17篇
  1995年   4篇
  1994年   7篇
  1993年   12篇
  1990年   2篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   4篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   4篇
  1977年   2篇
  1976年   9篇
  1972年   1篇
  1955年   1篇
排序方式: 共有158条查询结果,搜索用时 23 毫秒
1.
The case is described of a 58 year old man with systemic Whipple's disease with pericardial and pleural effusions and severe pulmonary hypertension. After three months of antibiotic treatment there was a complete resolution, not only of the symptoms known to be associated with Whipple's disease (diarrhoea, arthralgia, pericardial and pleural effusions), but also of pulmonary hypertension.  相似文献   
2.
3.
The high average power laser program is developing an inertial fusion energy demonstration power reactor with a solid first wall chamber. The first wall (FW) will be subject to high energy density radiation and high doses of high energy helium implantation. Tungsten has been identified as the candidate material for a FW armor. The fundamental concern is long term thermo-mechanical survivability of the armor against the effects of high temperature pulsed operation and exfoliation due to the retention of implanted helium. Even if a solid tungsten armor coating would survive the high temperature cyclic operation with minimal failure, the high helium implantation and retention would result in unacceptable material loss rates. Micro-engineered materials, such as castellated structures, plasma sprayed nano-porous coatings and refractory foams are suggested as a first wall armor material to address these fundamental concerns. A micro-engineered FW armor would have to be designed with specific geometric features that tolerate high cyclic heating loads and recycle most of the implanted helium without any significant failure. Micro-engineered materials are briefly reviewed. In particular, plasma-sprayed nano-porous tungsten and tungsten foams are assessed for their potential to accommodate inertial fusion specific loads. Tests show that nano-porous plasma spray coatings can be manufactured with high permeability to helium gas, while retaining relatively high thermal conductivities. Tungsten foams where shown to be able to overcome thermo-mechanical loads by cell rotation and deformation. Helium implantation tests have shown, that pulsed implantation and heating releases significant levels of implanted helium. Helium implantation and release from tungsten was modeled using an expanded kinetic rate theory, to include the effects of pulsed implantations and thermal cycles. Although, significant challenges remain micro-engineered materials are shown to constitute potential candidate FW armor materials.  相似文献   
4.
Given the good stability of mechanical properties of silicon carbide (SiC) under neutron irradiation, the ultimate irradiation tolerance of SiC composite materials may be limited by the fiber/matrix interphase, which is critically important to the performance of these composites. This study investigates the irradiation stability of pyrolytic carbon (PyC) monolayer and PyC/SiC multilayer interphases by tensile and single fiber push-out test techniques. Neutron irradiation was performed to doses of 0.7-7.7 dpa at temperatures from 380 to 1080 °C. Both interfacial debond shear strength and interfacial friction stress apparently decrease by irradiation, although this is not so dramatic when Tirr < 1000 °C. In contrast, the interfacial shear stresses are most affected by the higher temperature irradiation (>1000 °C). Noteworthy, these irradiation effects depend on the type of interphase material, i.e., for the pyrolytic carbon or multilayer SiC variants studied. In the range of irradiation temperature and dose, the degradation in interfacial shear properties, while measurable, is not of a magnitude to degrade the mechanical performance of the composites. This was observed for both interphase types studied. In particular, the proportional limit tensile stress decreases slightly by irradiation while the tensile fracture strength undergoes very minor change.  相似文献   
5.
Clinical signs, diagnosis, treatment and isolation of Neospora caninum from two littermate dogs are described. Three of six pups from a Labrador bitch developed paralysis. Neosporosis was diagnosed ante mortem by serological examination in two of the affected pups. At necropsy, tissue cysts were seen in unstained smears and in histologic sections of their brains. Tissue cysts were often thin-walled (approximately 1 micron) but antigenically and ultrastructurally identified as N. caninum. Furthermore, N. caninum (isolates NC-4, NC-5) was isolated in mice and in cell cultures inoculated with neural tissues of these two dogs. Serological diagnosis of neosporosis using a variety of tests is discussed.  相似文献   
6.
Hemorrhagic, oedema-forming activities and histopathological alterations in the mouse footpad induced by Bothrops and Crotalus snake venoms from Argentina. Hemorrhagic and oedema-forming activities of various Bothrops and Crotalus snake venoms from Argentina were studied, together with histological alterations in the mouse footpad. The highest oedema-forming activity was found in the venom of B. jararaca, followed by B. jararacussu, B. neuwiedii diporus, B. alternatus, and Crotalus durissus terrificus. Regarding hemorrhage, the highest activity was found in the venom of B. neuwiedii diporus, followed by B. jararacussu, B. alternatus, and B. jararaca. No hemorrhage was observed after injection of Crotalus durissus terrificus venom, in agreement with histological observations of injected footpads. Histological analysis revealed a conspicuous inflammatory reaction in the injected footpad, characterized by oedema and an inflammatory infiltrate rich in polymorphonuclear leucocytes. Necrotic blood vessels and dilated lymphatic vessels were observed after injection of B. jararaca and B. jararacussu venoms, and myonecrosis was evident in tissue of mice injected with B. alternatus and B. neuwiedii diporus.  相似文献   
7.
In this study the potential of intraperitoneal (i.p.) and intravenous (i.v.) administration of chimeric iodine-131-labelled MOv18 IgG for radioimmunotherapy was determined. The dosimetry associated with both routes of administration of cMOv18 IgG was studied in patients. Eight patients suspected of having ovarian carcinoma received 150 MBq 131I-cMOv18 IgG i.p. Blood and urine were collected and serial gamma camera images were acquired. Another group of four patients received 7.5 MBq 131I-cMOv18 IgG i.v. For all patients, tissue biopsies were obtained at surgery. Activity in the blood after i.p. administration was described by a bi-exponential curve with a mean uptake and elimination half-life of 6.9+/-3.2 h and 160+/-45 h, respectively. For i.v. infusion the mean half-life for the elimination phase was 103+/-12 h. Cumulative excretion in the urine was 17%+/-3% ID and 21%+/-7% ID in 96 h for i.p. and i.v. administration, respectively. Scintigraphic images after i.p. administration showed accumulation in ovarian cancer lesions, while all other tissues showed decreasing activity with time. Tumour uptake determined in the ovarian cancer tissue specimens ranged from 3.4% to 12.3% ID/kg for i.p. administration and from 3.6% to 5.4% ID/kg for i.v. administration. Dosimetric analysis of the data indicated that 1.7-4.3 mGy/MBq and 1.7-2.2 mGy/MBq can be guided to solid or ascites cells after i.p. and i.v. administration, respectively. Assuming that an absorbed dose to the bone marrow of 2 Gy will be dose limiting, a total activity of 4.1 GBq 131I-cMOv18 IgG can be administered safely via the i.p. route and 3.5 GBq via the i.v. route. At this maximal tolerated dose, a maximum absorbed dose to 1-g tumours in the peritoneal cavity of 18 and 8 Gy can be reached after i.p. and i.v. administration, respectively. For the i. p. route of administration, dose estimates for the tumour are even higher when the electron dose of the peritoneal activity is also taken into account: total doses to the tumour of 30 Gy and 22 Gy will be absorbed at the tumour surface and at 0.2 mm depth, respectively. In conclusion, therapeutic tumour doses can be achieved with 131I-cMOv18 IgG in patients with intraperitoneal ovarian cancer lesions with no normal organ toxicity. The i.p. route of administration seems to be preferable to i.v. administration.  相似文献   
8.
Describes 2 experiments in which a total of 192 undergraduates received 49 items of personal information previously scaled in terms of their intimacy and presented according to the method of constant stimuli. For each item, Ss indicated whether they believed they would have withheld or revealed that information under actual psychiatric interview conditions. Exp. I manipulated the professional role of the interviewer, confidentiality of obtained information, and sex of the interviewee in a 4 * 3 * 2 design. Results indicate that (a) Ss avowedly revealed more personal information to mental health professionals than they would in a control employment interview situation, with no differences between the mental health professionals; (b) informing Ss that the interview was not confidential produced significant information loss from female but not male Ss; and (c) Ss who received no information regarding confidentiality behaved like Ss who were told the information was confidential. In Exp. II, Ss were asked to assume the motivational-attitudinal state of persons either coerced or voluntarily seeking a psychiatric interview because they had violated interpersonal norms. Significant information loss occurred in coerced Ss while confidentiality had no effect on self-disclosure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
10.
C.L. Snead 《低温学》1976,16(7):399-400
A superconducting current switch is described, several of which can be stacked in a parallel array to allow the selection of a given sample to receive the high-current input from two current leads from the outside. The switch is a coil of superconducting wire which, when driven normal by a heater, shunts the current to a parallel, less-resistive leg. If such switches are stacked in parallel and (n ? 1) driven normal, all current goes through the superconducting member and its related sample. The configuration described here employs six switches with a test-current capability of 112 A to any sample.  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