全文获取类型
收费全文 | 2240篇 |
免费 | 0篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 8篇 |
金属工艺 | 1篇 |
轻工业 | 7篇 |
水利工程 | 1篇 |
无线电 | 3篇 |
一般工业技术 | 7篇 |
冶金工业 | 2207篇 |
原子能技术 | 1篇 |
自动化技术 | 3篇 |
出版年
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 1篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2010年 | 2篇 |
2007年 | 1篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 74篇 |
1998年 | 708篇 |
1997年 | 432篇 |
1996年 | 249篇 |
1995年 | 130篇 |
1994年 | 98篇 |
1993年 | 125篇 |
1992年 | 18篇 |
1991年 | 17篇 |
1990年 | 16篇 |
1989年 | 23篇 |
1988年 | 33篇 |
1987年 | 17篇 |
1986年 | 15篇 |
1985年 | 10篇 |
1983年 | 2篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 16篇 |
1978年 | 3篇 |
1977年 | 61篇 |
1976年 | 144篇 |
1975年 | 5篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1968年 | 1篇 |
1964年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有2240条查询结果,搜索用时 10 毫秒
81.
S Pursiheimo E Rintam?ki E Baena-Gonzalez EM Aro 《Canadian Metallurgical Quarterly》1998,423(2):178-182
A 32-year-old, previously healthy woman with a diffuse, complex tumoral process is described. While she was being evaluated for primary infertility, a laparoscopic procedure revealed a disseminated peritoneal process associated with bilateral ovarian lesions. A clinical diagnosis of stage III ovarian cancer was made and total hysterectomy, bilateral salpingo-oophorectomy, and omentectomy were performed. Pathologic studies showed an admixture of leiomyomatosis peritonealis disseminata (LPD) endometriosis, and an extensive multicystic mesothelial proliferation. Although endometriosis is known to occur in conjunction with either LPD or multicystic mesothelioma, to our knowledge this is the first report of all three lesions occurring simultaneously. 相似文献
82.
Retroperitoneoscope was introduced through the 11 and 10 intercostal space by linea axillaris media and anterior Differences of the accesses between each other and between those in lumbocostal angle are statistically significant. The access to 11 intercostal space was proved to be the most convenient one for the examination of the entire kidney surface, while the one to 10 intercostal space-for the endoscopy of adrenals and caudal region of the pancreas. The caput of the pancreas may be examined both through 11 intercostal space and lumbocostal angle. Clinical observations of 129 patients, operated by means of retroperitoneoscope through 11 intercostal space confirmed the effectivity of the method. Positive effects of retroperitoneoscopy_-minimal traumatization of tissues, normal postoperative period and good cosmetic effect make it suitable for wide introduction into the surgical practice. 相似文献
83.
84.
Characterization of a Schwann cell neurite-promoting activity that directs motoneuron axon outgrowth
The aim of the study described here was to correlate coronary artery (CA) stenosis pressure gradients calculated by quantitative coronary arteriography (QCA) to invasively measured transstenotic pressure drops in patients with anginal symptoms and with known or suspected coronary artery disease. Furthermore, the known mathematical models are improved by introducing (1) pressure catheter-corrected minimal stenosis area, (2) modification of flow assumptions, and (3) stenosis exit angle. Included in the study were 45 patients with 61 stenoses. The visually estimated CA lesion severity in these non-complex stenoses was in the equivocal range of 40-70%. All measurements were performed after intracoronary administration of nifedipine and nitroglycerin. Stenosis dimensions were assessed from magnified cinefilms, using hand-held calipers. Highly significant overall correlation was found between measured and calculated pressure gradients with correction for the impact of the intracoronary catheter (P < 0.00001, r = 0.84). In particular, a substantial number of stenoses with haemodynamically-insignificant pressure gradients were identified by hydrodynamic calculations. In conclusion, the great majority of the coronary artery stenoses could be classified reliably by QCA as being haemodynamically insignificant or significant, respectively. 相似文献
85.
EH Thall NN Stone DL Cheng EL Cohen EM Fine I Leventhal RA Aldoroty 《Canadian Metallurgical Quarterly》1996,77(4):512-517
This study examines whether, while controlling for local economic conditions, job design and other organizational factors affect facility aide turnover rates in a sample of 250 nursing homes from 10 states. Facility characteristics were largely based on administrator and director of nursing interviews conducted in 1993 as part of the Health Care Financing Administration's evaluation of the Resident Assessment Instrument (RAI) implementation. Aide turnover was significantly reduced by involvement in interdisciplinary care plan meetings. Turnover rates were higher in for-profit homes. Aide involvement in assessments, aide training and workload, case mix severity, payor source mix, and facility size were not significantly related to aide turnover. 相似文献
86.
From January 1981 through October 1995, a total of 28 patients underwent surgery for metastatic lung tumors in our institute. A retrospective review and survival analysis of these patients are reported. There were 12 males and 16 females, with the mean age of 57 years. Of them, 20 patients had solitary lesions. Pulmonary metastasis was from the colon in 8 patients, from the breast in 5, from the stomach and the uterus in each 3, from the bladder, the rectum and the soft tissue in each 2, and from the kidney, the ovarium and the thyroid in each 1. A lobectomy was performed in 22 patients, 17 of whom were accompanied with mediastinal lymph node dissection (R2a). Partial resection without lymph node dissection was performed in 6 patients (R0). Overall 5-year survival was 24.7%. Four-year or over survivor were 4 patients who underwent a lobectomy with R2a. The patients undergoing lobectomy had a significantly better prognosis compared with patients with partial resection (p<0. 05). The patients with R2a had significantly less local recurrence than patients with R1 or R0 (p<0.05). We conclude that lobectomy with R2a is suitable treatment for metastatic lung cancer. 相似文献
87.
EM Raynor JM Shefner MH Ross EL Logigian JA Hinchey 《Canadian Metallurgical Quarterly》1998,50(6):1907-1909
Nerve root stimulation may be employed in patients with motor neuron disease (MND) to rule out motor neuropathy with conduction block. The diagnostic utility of these studies is unknown, in part because the range of amplitude changes across nerve root segments in patients with active neuronal degeneration has not been well studied. We reviewed root stimulation studies in 32 patients (59 nerves) with MND and found segmental amplitude reduction from 0 to 45%, a range similar to values reported for normal subjects; there was no suggestion of conduction block based on our usual criteria. 相似文献
88.
EM Kim J Striegel Y Kim AJ Matas JS Najarian SM Mauer 《Canadian Metallurgical Quarterly》1994,45(5):1440-1445
We performed 73 kidney transplants in 51 patients with steroid-resistant nephrotic syndrome (SRNS) with focal segmental glomerular sclerosis (FSG) ages 18.4 +/- 12.8 (mean +/- SD) years. Recurrence of SRNS, defined by rapid onset of proteinuria, hypoalbuminemia and/or > 95% epithelial cell foot process effacement with or without the presence of FSG, occurred in 26 grafts in 16 patients. Acute renal failure (ARF) occurred in 16 of 26 (61.5%) grafts with recurrence versus 7 of 47 (14.9%) grafts without recurrence (P < 0.0001). ARF occurred in 4 of 9 (44.4%) living-related donor (LRD) recipients with recurrence and 3 of 21 (12.5%) LRD recipients without recurrence (NS). ARF in cadaver donor (CAD) recipients with recurrence was 12 of 17 (70.5%) versus 4 of 23 (17.4%) without recurrence (P < 0.0001). ARF was also higher in LRD or CAD with recurrence than in a control group of non-SRNS patients matched for age, sex and time of transplantation. Graft survival at one year was lower in patients with recurrence and ARF [4 of 16 (25%)] compared to patients with recurrence and no ARF [9 of 11 (82%), P < 0.01]. There was no difference in graft survival in patients without recurrence who did or did not have ARF. One or more acute rejection episodes occurred in all 16 patients with ARF and recurrence, in all 7 patients with ARF without recurrence, and in 7 of 10 patients with recurrence without ARF compared with only 11 of 40 (28%) of patients with neither recurrence nor ARF (P < 0.0001, < 0.001 and < 0.04, respectively).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
89.
EM Zelenkin KN Prozorovskaia AS Mirkin EG Zavgorodniaia AN Kandaurova 《Canadian Metallurgical Quarterly》1998,43(3):41-43
Effect of sodium hypochlorite disinfection of impressions on the size and quality of plaster models is studied. Twenty-minute submerging of silicone impressions in 0.5% sodium hypochlorite solution did not change their size and did not deteriorate the quality of surface and hardness of plaster models. Stomalgin impressions cannot be disinfected by sodium hypochlorite solution because of expressed destructive effect of this disinfectant on the impressions. 相似文献
90.