全文获取类型
收费全文 | 562篇 |
免费 | 2篇 |
专业分类
电工技术 | 4篇 |
综合类 | 2篇 |
化学工业 | 10篇 |
机械仪表 | 2篇 |
建筑科学 | 2篇 |
轻工业 | 7篇 |
水利工程 | 1篇 |
石油天然气 | 9篇 |
无线电 | 12篇 |
一般工业技术 | 14篇 |
冶金工业 | 494篇 |
原子能技术 | 3篇 |
自动化技术 | 4篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2018年 | 1篇 |
2016年 | 4篇 |
2014年 | 3篇 |
2013年 | 5篇 |
2012年 | 1篇 |
2011年 | 4篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 5篇 |
2001年 | 2篇 |
1999年 | 22篇 |
1998年 | 143篇 |
1997年 | 79篇 |
1996年 | 67篇 |
1995年 | 33篇 |
1994年 | 28篇 |
1993年 | 26篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 1篇 |
1988年 | 9篇 |
1987年 | 6篇 |
1985年 | 4篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1978年 | 2篇 |
1977年 | 16篇 |
1976年 | 41篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有564条查询结果,搜索用时 171 毫秒
211.
P Macchiarini AR Chapelier I Monnet JM Vannetzel JL Rebischung J Cerrina F Parquin FL Ladurie B Lenot PG Dartevelle 《Canadian Metallurgical Quarterly》1994,57(4):966-973
Twenty-three patients with stage IIIb (T4) non-small cell lung cancer received induction chemotherapy (median, 2 cycles) with (n = 12) or without (n = 11) radiation (median, 45 Gy) before operation. Nine tumors involved the carina (n = 8) or lateral tracheal wall (n = 1), 11 were located centrally and invaded the proximal pulmonary artery (n = 6), veins (n = 3), or both (n = 2), three were apical tumors involving T4 structures, and six were associated with histologically diseased mediastinal nodes. Five complete and 18 partial responses were observed after induction treatment. Resection of all residual tumor at the primary site and involved vestiges was possible in 21 patients (91%); in two apical tumors, tumor was left behind. Nine right tracheal sleeve and 11 intrapericardial pneumonectomies and three resections of apical tumors were performed; 11 patients (48%) had radical mediastinal lymph node dissection. Complete sterilization of the primary tumor was observed in 3 patients (13%). Mean operating time was 209.3 +/- 86.8 minutes, and mean blood loss was 896.9 +/- 1031 mL. Major postoperative complications occurred in 6 patients (26%), including hemothorax requiring drainage (n = 1) or reoperation (n = 1), acute distress syndrome (n = 2), and bronchopleural fistula (n = 2), and their incidence was significantly higher (p = 0.0003) among patients receiving induction chemoradiation than among those receiving chemotherapy alone (42 versus 9%). Early (< 1 month) postoperative mortality was 8.6% (n = 2). With a median follow-up of 25 months (range, 12 to more than 39 months), the projected 3-year overall survival was 54%.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
212.
213.
BJ Meester NP Shankley NJ Welsh J Wood FL Meijler JW Black 《Canadian Metallurgical Quarterly》1998,124(4):685-692
Factors influencing the change in bone mineral after 3 mo of lactation were investigated in 47 breast-feeding mothers, 11 formula-feeding mothers, and 22 nonpregnant, nonlactating control subjects. At 6-8 wk postpartum, the breast-feeding group had a mean (+/-SD) calcium intake of 34.8+/-13.2 mmol/d and breast-milk volume, calcium concentration, and calcium output of 0.865+/-0.230 L/d, 7.41+/-1.25 mmol/L, and 6.41+/-2.00 mmol/d, respectively. There was no relation between calcium intake and any breast-milk variable. Dual-energy X-ray absorptiometry of the whole body, spine, hip, and forearm was performed at 0.5 and 3 mo. There were significant decreases in bone mineral content at the spine (3.96%; 95% CI: 4.86%, 3.06%), femoral neck (2.39%; 95% CI: 3.61%, 1.17%), total hip (1.51%; 95% CI: 2.45%, 0.60%), and whole body (0.86%; 95% CI: 1.29%, 0.43%) in breast-feeding mothers but not in formula-feeding mothers or nonpregnant, nonlactating women. These changes were not related to calcium intake, breast-milk calcium concentration, vitamin D-receptor genotype, postpartum weight change, or use of the progesterone-only contraceptive pill. After adjustment for bone area, breast-milk volume and height were identified as significant predictors at the spine, such that greater decreases were associated with taller mothers (P = 0.007) and those with greater breast-milk volume (P = 0.001). This finding suggests that the marked bone mineral changes observed in breast-feeding mothers represented a physiologic response to lactation that was independent of dietary calcium supply. 相似文献
214.
Oocyte donation in premature ovarian failure patients has become an extended indication for In Vitro Fertilization (IVF) procedure. Here the first case report is presented in Taiwan, R.O.C. of a triplet pregnancy in a patient with premature ovarian failure. After an adequate hormonal replacement therapy with oral premarin and intramuscular progesterone for endometrium preparation, the transfer on D15 of four embryos (with donated oocytes and IVF) resulted in implantation of three. Pregnancy support was provided also by oral premarin and intramuscular progesterone until the tenth week of gestational age (GA). The patient received Caesarean section at 35 weeks GA with delivery of three healthy babies weighing 2530 gm, 2420 gm, and 1810 gm respectively on Aug. 17, 1990. 相似文献
215.
216.
C Bagnis FL Cosset J Samarut G Moscovici C Moscovici 《Canadian Metallurgical Quarterly》1993,8(3):737-743
The avian myeloblastosis virus (AMV) causes monoblastic leukemia in the chick. Two non-producer clones of AMV-transformed monoblasts, BM2/C3A and BM2L/A2B5, have been described (see Bottazzi et al., this issue). They differ in their growth requirements and in their ability to induce leukemia when injected into the chick embryo. We first genetically tagged these clones by retroviral infection with a vector expressing the bacterial lacZ gene. Then, we injected the lacZ-positive cells via the chorioallantoic vein into chick embryos. With BM2L/A2B5 cells, the bone marrow of the injected birds was rapidly invaded by lacZ-positive cells. In addition, these cells rapidly overgrew cultures of bone marrow cells derived from injected animals. Conversely, the growth of BM2/C3A was inhibited in the injected animals and only a few blue cells, with the morphology of macrophages, were detected in cultures of bone marrow cells. We developed an in vitro assay to mimic in vitro the differential growth of BM2/C3A and BM2L/A2B5 observed in vivo. These data strongly suggest that BM2/C3A cells retain their ability to differentiate into macrophages in the normal bone marrow environment and that BM2L/A2B5 cells differ from BMC/C3A in the loss of this capacity. 相似文献
217.
Malacoplakia is a chronic inflammatory disease the etiology of which remains obscure. It has a very low incidence and affects primarily the genitourinary tract, although it has been described in some other organs. This paper presents a historic insight of the clinical cases diagnosed in this centre, and includes a review and update of several issues related to this entity such as pathogenesis, pathological anatomy and treatment. Also, the peculiarities related to the involvement of each separate organ with regard to diagnosis, prognosis and treatment are described. 相似文献
218.
219.
Changes in soil microbial activity and diversity after incubation either with nitrogen or with a mixture of methane and air were examined. The perturbation by methane and air were characterized in detail and led to reduced diversity and enrichment of methanotrophs which were identified by denaturing gradient gel electrophoresis and 16S rRNA sequencing. 相似文献
220.
MB Mitchell DN Campbell DR Clarke DA Fullerton FL Grover MM Boucek B Pietra M Luna AL Shroyer JR Coll JW Rosky 《Canadian Metallurgical Quarterly》1998,116(2):242-252
OBJECTIVES: Our objectives were to (1) review our experience with heart transplants in infants (age < 6 months), (2) delineate risk factors for 30-day mortality, and (3) compare outcomes between our early and recent experience. METHODS: Records of all infants listed for transplantation in our center before September 1996 were analyzed. Early and recent comparisons were made between chronologic halves of the accrual period. Univariate analysis was used to analyze potential risk factors for 30-day mortality (categorical variables, Fisher's exact test; continuous variables, nonparametric Wilcoxon rank-sum test). Multivariable analysis included univariate variables with p values < or = 0.10. Actuarial survivals were estimated (Kaplan-Meier) and compared by the log-rank test. RESULTS: Fifty-one of the 60 infants listed for transplantation were operated on (waiting list mortality 15%). Thirty-day mortality was 18% overall, 30% in the first 3 years and 10% in the last 3 years (p = 0.07). Sepsis was the commonest cause of early death (4/9). Univariate analysis suggested four potential risk factors for early death: preoperative mechanical ventilation (p = 0.01), prior sternotomy (p = 0.002), preoperative inotropic drugs (p = 0.08), and warm ischemia time (p = 0.08). Multivariable analysis indicated that prior sternotomy (p = 0.01) was an independent risk factor for 30-day mortality. Actuarial survivals were 80%, 78%, and 70% at 1, 2, and 3 years, and these figures improved between early and recent groups (p = 0.05). Late deaths were most commonly due to acute rejection (3/5). CONCLUSIONS: Results of heart transplantation in infancy improve with experience. Prior sternotomy increases initial risk. Intermediate-term survival for infants with end-stage heart disease is excellent. 相似文献