全文获取类型
收费全文 | 1049篇 |
免费 | 2篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 13篇 |
金属工艺 | 2篇 |
机械仪表 | 1篇 |
建筑科学 | 2篇 |
能源动力 | 2篇 |
轻工业 | 22篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 4篇 |
一般工业技术 | 14篇 |
冶金工业 | 974篇 |
自动化技术 | 8篇 |
出版年
2021年 | 1篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 14篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 1篇 |
1999年 | 38篇 |
1998年 | 298篇 |
1997年 | 190篇 |
1996年 | 115篇 |
1995年 | 59篇 |
1994年 | 56篇 |
1993年 | 54篇 |
1992年 | 10篇 |
1991年 | 19篇 |
1990年 | 14篇 |
1989年 | 22篇 |
1988年 | 24篇 |
1987年 | 18篇 |
1986年 | 20篇 |
1985年 | 11篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 9篇 |
1976年 | 20篇 |
1975年 | 3篇 |
1972年 | 1篇 |
1966年 | 1篇 |
1956年 | 1篇 |
1955年 | 1篇 |
1954年 | 2篇 |
排序方式: 共有1051条查询结果,搜索用时 15 毫秒
21.
22.
23.
ST O'Sullivan M O'Sullivan N Pasha M O'Shaughnessy TP O'Connor 《Canadian Metallurgical Quarterly》1997,28(9-10):639-642
The patient with severe lower limb trauma presents a management dilemma; whether to amputate primarily or to attempt limb salvage. In recent years, many predictive indices have been published which purport to identify limbs which are non-viable. We retrospectively applied two recently described indices, the Mangled Extremity Severity Score (MESS) and the Limb Salvage Index (LSI), to 54 limbs in 50 patients with either Gustilo IIIB or IIIC complex tibial fractures. There were 22 amputations (40.7 per cent) in the series. The mean MESS score in the limb salvage group was 3.8 (range 2-10), and the mean MESS score in the amputation group was 7.7 (range 4-13) (P < 0.0001). The mean LSI score in the limb salvage group was 3.6 (range 3-8), and the mean LSI score in the amputation group was 6.9 (P < 0.01). However, in the group with MESS scores > 7 (which recommends amputation), there were three limbs which were salvaged with acceptable functional outcome. Similarly, in those with LSI scores > 6 (which recommends amputation), there were seven limbs successfully salvaged. A MESS > 7 offered a greater relative risk of amputation (9.2) than a LSI score > 6 (5.3). We found both indices of use in predicting limb salvage and functional outcome. However, neither is sufficiently accurate to be considered absolutely reliable in clinical practice. 相似文献
24.
Conventional constant angular velocity sampling of the surface of a sphere results in a higher sampling density near the two poles relative to the equatorial region. More samples, and hence longer sampling time, are required to achieve a given sampling density in the equatorial region when compared with uniform sampling. This paper presents a simple expression for a continuous sample path through a nearly uniform distribution of points on the surface of a sphere. Sampling of concentric spherical shells in k-space with the new strategy is used to design 3D selective inversion and spin-echo pulses. These new 3D selective pulses have been implemented and verified experimentally. 相似文献
25.
ST Yildiran S K?mürcü MA Sara?li A G?nlüm C Beyan H Gün A Yal?in 《Canadian Metallurgical Quarterly》1998,41(11-12):467-469
We report two cases of Fusarium infection with evidence of fungaemia in severely neutropenic patients with leukaemia. One patient was a 65-year-old woman with chronic lymphocytic leukaemia infected by Fusarium verticillioides. The other patient was a 45-year-old woman with acute myeloblastic leukaemia infected by Fusarium spp. Fungaemia was the only evident manifestation of these fungal infections. 相似文献
26.
The morphological organization of the globus pallidus (GP), the subthalamic nucleus (STN), and the pallidosubthalamic projection was studied in organotypic cultures. Coronal slices from the GP, the STN, the striatum (CPu), and the cortex (Cx) were taken from the rat after postnatal days 0-2 and grown for 2 or 5-6 weeks. For analysis, immunocytochemistry against glutamate (GLU), parvalbumin (PV), and calretinin (CR) was combined with confocal microscopy. After 2 weeks in vitro, the STN showed a densely packed, homogeneous GLU-immunoreactive (ir) cell population. Pallidal GLU-ir neurons were heterogeneous, consisting of large-sized weakly GLU-ir neurons and small-sized intensively GLU-ir neurons. After 5-6 weeks in vitro, pallidal axons had radiated from numerous large-sized PV-ir cells and selectively innervated the STN, where they heavily ramified. Cultured STN neurons were not stained for PV; however, multipolar intensely PV-ir neurons were located at the border of the STN with their dendrites oriented towards the STN. Double labeling for PV and CR in both mature cultures and in the adult rat revealed that the culture CR-ir neurons from the GP, the Cpu, and from areas adjacent to the STN were different from cultured PV-ir neurons and their morphologies and distribution corresponded to that in vivo. These results demonstrate that 1) cultured CP and STN neurons display similar morphologies found in in vivo, 2) PV-ir pallidal neurons heavily and selectively innervate the STN; 3) there is a specific class of STN border neurons; and 4) in contrast to the in vivo situation, most cultured STN neurons are PV-negative. 相似文献
27.
PURPOSE: Two cases of abdominal compartment syndrome are described and the pathophysiology associated with it is reviewed. CLINICAL FEATURES: The first patient was a 46-yr-old man who sustained extensive blunt abdominal injuries following a fall. The second was a 54-yr-old man involved in a motor vehicle accident with blunt abdominal trauma. In both cases, the patients developed an extremely tense abdomen, increasing peak inspiratory pressures, hypercarbia and oliguria. Both demonstrated improvement in cardiac performance and ventilatory variables following an emergency decompressive celiotomy. CONCLUSION: Abdominal compartment syndrome results in impairment of organ function secondary to increased intraabdominal pressure. These patients require emergency decompressive celiotomy to relieve the symptoms. However, the incidence of intractable asystole and hypotension during this procedure is high and vigilance must be maintained during the release of the increased intraabdominal pressure. 相似文献
28.
WP Lin DD Ji CY Shiau TC Yang YW Yang TL Tsou ST Tang CH Chen YT Liu 《Canadian Metallurgical Quarterly》2003,142(3):158-165
Compounds N-(6,7-difluoroquinolonyl)-ampicillin (AU-1) and N-(6-fluoroquinolonyl)-ampicillin (FQ-1), synthesized by coupling of the carboxyl group of 6,7-difluoroquinolone (FP-3) and 6-fluoroquinolone (FP4), respectively, with the alpha-amino-group of ampicillin side chain, exhibit antipseudomonal activity similar to and lower acute toxicity than that of norfloxacin, whereas neither ampicillin nor the fluoroquinolone moieties, compound FP-3 or FP4, alone have such activity. Also, AU-1 and FQ-1 are active against tested clinical isolates of Pseudomonas aeruginosa that are highly resistant to norfloxacin, gentamicin, or both. The therapeutic efficacies of FQ-1 and norfloxacin were assessed and compared in neutropenic mice infected with a 90% lethal dose of P aeruginosa. Mice intraperitoneally administered FQ-1 (10 mg/kg) 4, 8, 24, and 48 hours after infection had survival rates as high as 80%, comparable to those of mice treated with norfloxacin at the same dosage and dosing schedule. The study of protoplast formation revealed that FQ-1 did not inhibit cell-wall biosynthesis but did induce cell filamentation of Bacillus subtilis at a level close to its minimal inhibition concentration. Both AU-1 and FQ-1 were able to intercalate into the double-stranded DNA. However, that FQ-1 lost such activity after it was treated with penicillinase suggests that the lactam-ring structure in ampicillin moiety of FQ-1 was hydrolyzed by penicillinase and that the hydrolyzed structure of FQ-1 does not own DNA-intercalation activity. 相似文献
29.
ST Cornelius 《Canadian Metallurgical Quarterly》1997,68(4):159-161
One of the most complex and troubling issues facing society and health care professionals is physician-assisted suicide (PAS). The convergence of significant trends in legislation, judicial decisions, research, and public sentiment has highlighted its importance. A broad spectrum of societal opinion and philosophical, religious, legal, and professional debate surrounds PAS. 相似文献
30.