全文获取类型
收费全文 | 497篇 |
免费 | 1篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 9篇 |
机械仪表 | 3篇 |
建筑科学 | 4篇 |
能源动力 | 11篇 |
轻工业 | 10篇 |
石油天然气 | 4篇 |
无线电 | 9篇 |
一般工业技术 | 12篇 |
冶金工业 | 414篇 |
自动化技术 | 17篇 |
出版年
2015年 | 4篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 1篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 115篇 |
1997年 | 62篇 |
1996年 | 35篇 |
1995年 | 29篇 |
1994年 | 25篇 |
1993年 | 29篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 10篇 |
1976年 | 31篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1961年 | 1篇 |
1957年 | 1篇 |
1931年 | 1篇 |
排序方式: 共有498条查询结果,搜索用时 15 毫秒
91.
AF Kardinaal MS Morton IE Brüggemann-Rotgans EC van Beresteijn 《Canadian Metallurgical Quarterly》1998,52(11):850-855
OBJECTIVE: The hypothesis was tested that the rate of postmenopausal bone loss is inversely associated with long-term urinary excretion of phyto-oestrogens, as a marker of habitual dietary intake. DESIGN: Secondary analysis of a 10-year follow-up study (1979 1989) among postmenopausal women in the Netherlands. SUBJECTS: From the original population of 154 women, 32 women were selected with an annual rate of radial bone loss of < or = 0.5% over the first 5 years of the study and 35 women with a rate of > or = 2.5% per year. METHODS: The isoflavonoids genistein, daidzein and equol, and the lignan enterolactone were determined by gas chromatography mass spectrometry in aggregate samples from annually collected urine samples. Cortical bone density of the radius had previously been measured annually by single-photon absorptiometry. RESULTS: Excretion of isoflavonoids did not differ between both groups, although in multivariate analysis equol excretion was weakly positively associated with rate of bone loss in the 5 years after the menopause. Enterolactone excretion was significantly higher in the group with high rate of bone loss. This positive association remained in multivariate linear regression analysis after adjustment for age, years since menopause, body mass index and intake of calcium, vegetable protein and dietary fibre. CONCLUSIONS: Enterolactone excretion is likely to be an indicator of consumption of grains and legumes; it is not clear whether the observed positive association with rate of bone loss is a causal one. Our results do not support a preventive effect of low, unsupplemented dietary intake of phyto-oestrogens on postmenopausal cortical bone loss. However, no conclusions can be drawn about effects of higher doses of phyto-oestrogens. 相似文献
92.
OBJECTIVE: To determine the level of a single transverse scan of intra-abdominal fat between L1 and L5 vertebrae that best predicts intra-abdominal fat volumes. SUBJECTS: Sixteen male and seven female patients with non-insulin-dependent diabetes mellitus, aged 44-74 y. OUTCOME MEASURES: Volumes and areas from single scans of intra-abdominal fat measured by magnetic resonance imaging with a 1.5 Tesla magnetic field strength. RESULTS: Intra-abdominal fat volumes and were calculated from fat areas from eight cross-sectional transverse single scans (nine scans in eight men) of 20 mm thickness. Men and women, respectively, had mean body mass index (BMI) of 27.9 (s.d. 3.0) and 31.6 (s.d. 4.7) kg/m2, and intra-abdominal fat of 2.3 (s.d. 0.5) and 2.5 (s.d. 0.6) kg. Intra-abdominal fat area of the fourth scan (in the direction of L1 to L5) gave the highest prediction of total intra-abdominal fat both in men (r = 0.959, P < 0.001) and in women (r = 0.973, P < 0.001). The intra-abdominal fat area of the third scan gave almost as good a prediction. These third and fourth scans corresponded to L2 and L3 vertebrae. The intra-abdominal fat areas from the sixth and seventh scans, corresponded to the frequently used L4-L5 and had lower correlations with intra-abdominal fat. There were no gender differences in the prediction of volumes from areas of intra-abdominal fat. Intra-abdominal fat areas of the fourth scan explained 93% of variance (SEE = 0.14 kg) of total of intra-abdominal fat for both genders: intra-abdominal fat (kg) = 0.0108 x intra-abdominal fat area of the fourth scan (cm2) + 0.244. CONCLUSIONS: In large studies of intra-abdominal fat, using magnetic resonance imaging (MRI) or computerised tomography scanning, a single intra-abdominal fat area at the intervertebral disc between L-2 and L-3 vertebrae offers a cheaper, faster and safer method, with high prediction of total intra-abdominal fat volumes and masses. 相似文献
93.
PN Mainwaring MC Nicolson T Hickish R Penson S Joel M Slevin IE Smith 《Canadian Metallurgical Quarterly》1997,76(12):1636-1639
Two open, phase II studies were performed to evaluate the activity and toxicity of infusional topotecan in patients with advanced non-small-cell lung carcinoma (NSCLC) and advanced breast cancer who had not received previous chemotherapy for metastatic disease. Twenty-five patients with an ECOG performance score < 2 were treated with infusional topotecan administered as a daily, continuous intravenous infusion starting at 0.6 mg m(-2) day(-1) (NSCLC) and 0.5 mg m(-2) day(-1) (breast cancer) for 21 days every 4 weeks. Three patients achieved a partial response as defined by WHO criteria: one with NSCLC (8%; 95% CI 0-39%) and two with advanced breast cancer (15%; 95% CI 2-45%). The major toxicities were neutropenia and thrombocytopenia, with one episode of neutropenic sepsis. These data suggest that topotecan delivered as a continuous intravenous infusion over 21 days as single-agent therapy does not appear to offer a clinical advantage over conventional 5-day schedules against advanced NSCLC and advanced breast cancer. 相似文献
94.
IE Gushanski? 《Canadian Metallurgical Quarterly》1997,97(12):20-23
There were studied 23 schizophrenic and cyclothymic patients with stable agoraphobia in the structure of anxiousphobic disorders (APD). No absolute correlation was found between stability of agoraphobia and severity of panic disorder (frequency and intensity of panic attacks). It was established that APD with manifestations of agoraphobia had been, perhaps, conditioned by the presence of comorbid disturbances in their structure which had determined peculiarities of the patients' behavior. Two types of prolonged APD with agoraphobic phenomena were recognized. Retention of agoraphobic disturbances in conditions of the first type was related to symptoms of generalized somatic disorder (generalized somatic anxiety) in clinical pattern of APD. Manifestations similar to panphobias prevailed, agoraphobic avoidance included all the situations in which the patient could find himself without help. In the states of the second type retention of agoraphobic disorders was conditioned by comorbidity of APD with asthenohypochondriac manifestations with somato-psychic fragility in their structure. Anxiety of expectation was formed in situations with emotional or physical tension. Agoraphobic avoidance in conditions of this type had displayed the character of preventive measures and one of manifestations of hypochondriac development of personality. The presence of pronounced anxiety (intensive panic attacks, generalized anxiety) in clinical pattern of prolonged agoraphobic conditions can serve a predictor of a favourable development of the disease. 相似文献
95.
96.
EM Cornford S Hyman ME Cornford RT Damian MJ Raleigh 《Canadian Metallurgical Quarterly》1998,57(7):699-713
Cellular distribution of the Glut1 glucose transporter in normal primate brains was analyzed by immunogold electron microscopy. Two configurations of endothelial Glut1 glucose transporter (high and low density capillaries) have been found in resections of traumatically injured and epileptogenic human brain; the objective of the present study was to ascertain whether these same 2 capillary populations, expressing high and low glucose transporter densities, were the common configuration in normal brain. The relative numbers of Glut1 glucose transporter-associated gold particles on luminal and abluminal endothelial cell membranes were determined within the cerebral cortex of several normal, nonhuman primates. Low Glut1 densities were seen in brain endothelia of both the rhesus and squirrel monkey cortex, with slightly greater quantities of Glut1 in vervet monkey cortices. The Glut1 transporter was most highly expressed in the baboon cortex, approaching the concentrations seen in human brains. In the rhesus, squirrel, and vervet monkeys, Glut1 concentrations were greater on the abluminal than luminal capillary membranes. In contrast, mean luminal membrane Glut1 concentrations were greater in baboons, resembling the distribution seen in the human brain. Brain regional differences in transporter concentration were seen in comparing membrane densities in the baboon cortex (approximately 15 Glut1-gold particles per micrometer), hippocampus (approximately 12 Glut1 gold particles per micrometer), cerebellum (approximately 6 Glut1-gold particles per micrometer), and retinal microvasculature (approximately 20 Glut1-gold particles per micrometer). We conclude that a single, uniform Glut1 distribution characterizes brain capillaries of normal nonhuman primates, and hypothesize that the presence of high and low density glucose transporter endothelial cells (seen in human traumatic injury and seizure resections) represents a pathologic response to brain insult. 相似文献
97.
We report the results of a questionnaire sent to anaesthetists and midwives on the use of obstetric analgesia and anaesthesia in Norwegian hospitals in 1996. 95% of the 49 hospitals involved responded to the questionnaire, representing a total of 56,884 births. The use of epidural analgesia in labour varied from 0 to 25% in the different hospitals with a mean value of 15%. Epidural analgesia was much more widely used in university and regional hospitals than in local hospitals (p < 0.001). Five of the local hospitals did not offer epidural analgesia during labour at all. The combination of low-dose local anaesthetic and an opioid (either sufentanil or fentanyl) had not been introduced in nine of the hospitals (20%). The optimal use of epidural analgesia to relieve labour pain was judged to be more frequent by the anaesthetists than by the midwives (19% versus 11%, p < 0.01). In response to what factors limited the frequency of epidural analgesia, the anaesthetists specified factors related to the attitude of the midwife, and the midwives specified factors related to the anaesthetist. Only five of the hospitals provided written information on the various analgesic methods that could be employed during labour. The majority of midwives considered the analgesic methods employed on their maternity ward to be good or excellent. The frequency of Caesarean section was 12%; spinal anaesthesia was used in 55%, epidural anaesthesia in 17%, and general anaesthesia in 28% of the cases. 相似文献
98.
Charman Steve D.; Gregory Amy Hyman; Carlucci Marianna 《Canadian Metallurgical Quarterly》2009,15(1):76
Facial composite research has generally focused on the investigative utility of composites—using composites to find suspects. However, almost no work has examined the diagnostic utility of facial composites—the extent to which composites can be used as evidence against a suspect. For example, detectives and jurors may use the perceived similarity of a suspect to a composite as evidence to determine the likelihood of a suspect's guilt. However, research in social cognition and models of cognitive coherence suggest that these similarity judgments may be biased by evaluators' preexisting beliefs of guilt. Two studies examined how preexisting beliefs of guilt influence similarity ratings between a suspect and a facial composite. Study 1 (n = 93) demonstrated that mock-investigators' beliefs in a suspect's guilt inflated their subsequent similarity ratings. Study 2 (n = 49) demonstrated that mock-jurors' beliefs in a defendant's guilt predicted their similarity ratings. These findings highlight a problem of using facial composites as evidence against a suspect, and demonstrate the malleability of similarity judgments. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
99.
100.