全文获取类型
收费全文 | 4150篇 |
免费 | 8篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 58篇 |
金属工艺 | 17篇 |
机械仪表 | 3篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 6篇 |
轻工业 | 29篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 25篇 |
一般工业技术 | 27篇 |
冶金工业 | 3954篇 |
原子能技术 | 2篇 |
自动化技术 | 23篇 |
出版年
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 10篇 |
2016年 | 2篇 |
2014年 | 3篇 |
2013年 | 15篇 |
2012年 | 16篇 |
2011年 | 14篇 |
2010年 | 5篇 |
2009年 | 8篇 |
2008年 | 13篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 11篇 |
2003年 | 16篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 144篇 |
1998年 | 1292篇 |
1997年 | 797篇 |
1996年 | 492篇 |
1995年 | 248篇 |
1994年 | 223篇 |
1993年 | 228篇 |
1992年 | 20篇 |
1991年 | 39篇 |
1990年 | 37篇 |
1989年 | 53篇 |
1988年 | 37篇 |
1987年 | 34篇 |
1986年 | 26篇 |
1985年 | 26篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1982年 | 15篇 |
1981年 | 24篇 |
1980年 | 29篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1977年 | 58篇 |
1976年 | 136篇 |
1975年 | 3篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有4158条查询结果,搜索用时 15 毫秒
31.
R Gutiérrez del Pozo MJ Ricart Brulles MC Bacque L Fernández-Cruz R Talbot-Wright P Carretero González 《Canadian Metallurgical Quarterly》1997,21(10):950-955
OBJECTIVE: Retrospective study of urological complications in our series of reno-pancreatic transplants. MATERIAL AND METHODS: Between February 1983 and May 1994 our group has conducted 93 RPT, 80 of which, mean age 36 +/- 6 years (24-54 years), are studied in this paper: 57 male and 23 female with an average time in dialysis of 20 +/- 15 months (0-84 months) and diabetes evolution of 21 +/- 5 years (11-37 years). RESULTS: Actuarial annual survival of patient, renal graft and pancreatic graft has been 85%, 79% and 74% respectively. Haematuria: 25% incidence, with graft pancreatitis etiology in 16 cases, rejection in 8 and urinary fistula in 6. Urinary infection: 85% incidence, symptomatic in 23 patients (29%) and asymptomatic in the remaining cases. Dysuria, urethritis and urethral stenosis: 14 patients, all male, most with both conditions associated. Reconversion of pancreatic exocrine secretion by intestinal route was performed in 7 patients. Urinary fistula: secondary to surgery in 9 cases and rejection in 4. Etiology of one case remained unknown. In 4 cases it was resolved with conservative treatment, and with surgical correction in 8. One patient required pancreatic transplantectomy and one patient died of AMI. CONCLUSIONS: Urological complication in RPT account for a significant morbidity, urinary fistula being the one with greater repercussion on the patient and pancreatic graft survival. 相似文献
32.
33.
Quantitative RT-PCR for measuring gene expression 总被引:1,自引:0,他引:1
34.
35.
BA Rybicki MJ Maliarik M Major J Popovich MC Iannuzzi 《Canadian Metallurgical Quarterly》1997,18(4):707-717
Hereditary susceptibility to sarcoidosis is suggested by ethnic preponderance, familial clustering, and multigenerational involvement. The genetics of sarcoidosis cannot be adequately addressed in small samples of patients; a large-scale study with stratification for patient phenotypic differences is necessary. A study that uses both genetic marker and environmental data would be able to control for and examine different causative mechanisms. Until such a well-designed, comprehensive study is carried out, we are left with interesting patterns of disease in families and uncertain allelic associations. 相似文献
36.
P Pirazzoli E Cacciari R De Iasio MC Pittalis P Dallacasa S Zucchini S Gualandi S Salardi C David S Boschi 《Canadian Metallurgical Quarterly》1997,77(2):F100-F104
AIMS: To evaluate the developmental pattern of fetal growth hormone (GH), insulin-like growth factor I (IGF-I), GH binding protein (GHBP) and IGF binding protein-3 (IGF-3); to determine the implications for fetal growth. METHODS: Serum GH, IGF-I, GHBP and IGFBP-3 were measured in 53 fetuses, 41 aged 20-26 weeks (group A) and 12 aged 31-38 weeks (group B). Fetal blood samples were obtained by direct puncture of the umbilical vein in utero. Fetal blood samples were taken to rule out beta thalassaemia, chromosome alterations, mother to fetus transmissible infections, and for maternal rhesus factor. GHBP was determined by gel filtration chromatography of serum incubated overnight with 125I-GH. GH, IGF-I and IGFBP-3 were determined by radioimmunoassay. RESULTS: Fetal serum GH concentrations in group A (median 29 micrograms/l, range 11-92) were significantly higher (P < 0.01) than those of group B (median 16.7 micrograms/l, range 4.5-29). IGF-I in group A (median 20 micrograms/l, range 4.1-53.3) was significantly lower (P < 0.01) than in group B (median 75.2 micrograms/l, range 27.8-122.3). Similarly, IGFBP-3 concentrations in group A (median 950 micrograms/l, range 580-1260) were significantly lower than those of group B (median 1920 micrograms/l, range 1070-1770). There was no significant difference between GHBP values in group A (median 8.6%, range 6.6-12.6) and group B (median 8.3%, range 6-14.3). Gestational age correlated positively with IGF-I concentrations (P < 0.0001) and IGFBP-3 (P < 0.0001) and negatively with GH (P < 0.0001). GHBP values did not correlate with gestational age. Multiple regression analysis showed a negative correlation between GH:IGF-I ratio and fetal growth indices CONCLUSIONS: The simultaneous evaluation of fetal GH, IGF-I, IGFBP-3 and GHBP suggests that the GH-IGF-I axis might already be functional in utero. The progressive improvement in the efficiency of this axis in the last part of gestation does not seem to be due to an increase in GH receptors. 相似文献
37.
Hyperdynamic circulation of cirrhotic rats: role of substance P and its relationship to nitric oxide
CJ Chu FY Lee SS Wang FY Chang YT Tsai HC Lin MC Hou SL Wu CC Tai SD Lee 《Canadian Metallurgical Quarterly》1997,32(8):841-846
BACKGROUND: It has been suggested that excessive formation of nitric oxide (NO) is responsible for the hyperdynamic circulation observed in portal hypertension. Substance P is a neuropeptide partly cleared by the liver and causes vasodilatation through the activation of the endothelial NO pathway. However, there are no previously published data concerning the plasma level of substance P in cirrhotic rats and its relationship to NO. METHODS: Plasma concentrations of substance P and nitrate/nitrite (an index of NO production) were determined in control rats and cirrhotic rats with or without ascites using an enzyme-linked immununosorbent assay and a colorimetric assay, respectively. In addition, systemic and portal hemodynamics were evaluated by a thermodilution technique and catheterization. RESULTS: Cirrhotic rats with and without ascites had a lower systemic vascular resistance (2.6 +/- 0.2 and 3.9 +/- 0.4 mmHg ml(-1) x min x 100 g body weight, respectively) and higher portal pressure (14.6 +/- 0.6 and 11.3 +/- 1.8 mmHg) than control rats (6.5 +/- 0.3 mmHg x ml(-1) x min x 100 g BW and 6.8 +/- 0.2 mmHg, respectively, P < 0.05), and cirrhotic rats with ascites had the lowest systemic vascular resistance. Plasma levels of nitrate/nitrite progressively increased in relation to the severity of liver dysfunction (control rats, 2.7 +/- 0.5 nmol/ml; cirrhotic rats without ascites, 5.6 +/- 1.3 nmol/ml; cirrhotic rats with ascites, 8.3 +/- 2.2 nmol/ml; P < 0.05). Cirrhotic rats with ascites displayed higher plasma values of substance P (57.7 +/- 5.9 pg/ml) than cirrhotic rats without ascites (37.9 +/- 3.1 pg/ml, P < 0.05) and control rats (30.1 +/- 1.0 pg/ml, P < 0.05). There was no significant difference in plasma substance P values between control rats and cirrhotic rats without ascites (P > 0.05). No correlation was found between plasma levels of substance P and nitrate/nitrite (r = 0.318, P > 0.05). CONCLUSIONS: Excessive formation of NO may be responsible, at least partly, for the hemodynamic derangements in cirrhosis. Although substance P may not participate in the initiation of a hyperdynamic circulation in cirrhosis, it may contribute to the maintenance of the hyperdynamic circulation observed in cirrhotic rats with ascites. 相似文献
38.
N Benito A Nú?ez M de Górgolas J Esteban T Calabuig MC Rivas ML Fernández Guerrero 《Canadian Metallurgical Quarterly》1997,157(14):1577-1580
BACKGROUND: Fever is commonly observed in patients with human immunodeficiency virus (HIV) disease and frequently eludes diagnosis. The role of bone marrow biopsy in the diagnosis of fever of unknown origin in patients infected with HIV remains controversial. PATIENTS AND METHODS: One hundred twenty-three consecutive patients with 137 episodes of fever lasting 10 or more days without diagnosis after 1 week of hospitalization were evaluated by bone marrow biopsy. RESULTS: Overall, a specific diagnosis was achieved in 52 episodes by means of culture and histopathological examination (diagnostic yield, 37.9%). Three types of disease were found: mycobacterial infections (n = 36, 69% of documented episodes), including 18 patients with disseminated tuberculosis and 14 with Mycobacterium avium-intracellulare complex infections; non-Hodgkin lymphomas (n = 12, 23%); and visceral leishmaniasis (n = 4, 8%). Although bone marrow cultures were more sensitive than microscopic examination with special stains for the diagnosis of mycobacterial infections, the pathological examination of bone marrow led to a more rapid diagnosis of disease. In addition, the histopathological examination of bone marrow alone led to the diagnosis of a specific condition in 43 episodes (31.3% of all episodes). CONCLUSIONS: Bone marrow biopsy is a useful procedure for the diagnosis of fever in patients with advanced HIV disease, particularly in areas where tuberculosis and leishmaniasis are prevalent. Involvement of the marrow may be the first indication of the existence of extranodal non-Hodgkin lymphoma. For Mycobacterium avium-intracellulare complex infection, blood cultures were more sensitive than bone marrow biopsy. 相似文献
39.
SS Gropper MC Naglak M Nardella A Plyler S Rarback S Yannicelli 《Canadian Metallurgical Quarterly》1993,12(2):108-114
Adequacy of nutrient intakes of adolescents with and without phenylketonuria (PKU) and infants and children with and without maple syrup urine disease (MSUD) were assessed using 3-day diet records sorted by disease and by age of the subject. Mean intakes of all nutrients were greater than two-thirds of the Recommended Dietary Allowances (RDA) or Estimated Safe and Adequate Daily Dietary Intakes (ESADDI) for all adolescents studied, with the exception of selenium (Se) in PKU adolescents, which averaged 27.8 micrograms. For adolescents with PKU, > 50% of the RDA or ESADDI for all nutrients was provided by elemental or modified protein hydrolysate medical foods, except for vitamin A in children aged 11-15 years and Se in children 11-18 years. Mean nutrient intakes of all infants and children were greater than two-thirds of the RDA or ESADDI for all nutrients except Se in MSUD children aged 1-11 years, where intakes ranged from 6.4 to 13.2 micrograms (21-66% of the RDA). The medical foods provided for most of the RDA and ESADDI recommendations, with the exception of Se in MSUD children. 相似文献
40.
S Petrasch LJ van Tits HJ Motulsky OE Brodde MC Michel 《Canadian Metallurgical Quarterly》1993,43(8):904-908
The effects of the antiasthmatic drug ketotifen (CAS 34580-13-7) on human mononuclear leukocytes were studied in vitro and in vivo. In vitro ketotifen concentration-dependently inhibited mitogen-stimulated lymphocyte proliferation. High ketotifen concentrations also inhibited T-lymphocyte mitogen- and adenosine triphosphate stimulated increases in intracellular Ca2+ in lymphocytes and the U937 human monocyte precursor cell line, respectively; this involved inhibition of both Ca2+ influx and intracellular mobilization. In in vivo experiments, treatment of healthy volunteers with 1 mg ketotifen b.i.d. for 7 d did not alter the number or subset composition of circulating lymphocytes. Moreover, the mitogen-stimulated in vitro proliferation of lymphocytes obtained before and after ketotifen treatment in vivo was similar. It is concluded that high ketotifen concentrations can inhibit the activation of resting lymphocytes in vitro but standard ketotifen treatment does not notably affect the number of function of circulating lymphocytes in vivo. 相似文献