全文获取类型
收费全文 | 1449篇 |
免费 | 0篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 17篇 |
金属工艺 | 4篇 |
机械仪表 | 2篇 |
建筑科学 | 1篇 |
能源动力 | 14篇 |
轻工业 | 9篇 |
石油天然气 | 1篇 |
无线电 | 10篇 |
一般工业技术 | 15篇 |
冶金工业 | 1359篇 |
自动化技术 | 16篇 |
出版年
2021年 | 2篇 |
2020年 | 1篇 |
2018年 | 2篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 9篇 |
2012年 | 2篇 |
2011年 | 7篇 |
2010年 | 1篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 5篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 4篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 37篇 |
1998年 | 448篇 |
1997年 | 214篇 |
1996年 | 169篇 |
1995年 | 76篇 |
1994年 | 64篇 |
1993年 | 90篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 16篇 |
1989年 | 14篇 |
1988年 | 19篇 |
1987年 | 10篇 |
1986年 | 11篇 |
1985年 | 14篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 55篇 |
1976年 | 84篇 |
1975年 | 1篇 |
1972年 | 2篇 |
1970年 | 1篇 |
1957年 | 1篇 |
1955年 | 1篇 |
1954年 | 1篇 |
1949年 | 1篇 |
排序方式: 共有1449条查询结果,搜索用时 15 毫秒
61.
WC Duckworth CD Saudek A Giobbie-Hurder WG Henderson RR Henry DE Kelley SV Edelman FJ Zieve RA Adler JW Anderson RJ Anderson BP Hamilton TW Donner MS Kirkman NA Morgan 《Canadian Metallurgical Quarterly》1998,21(10):1596-1602
OBJECTIVE: To determine whether implantable insulin pump (IIP) and multiple-dose insulin (MDI) therapy have different effects on cardiovascular risk factors in insulin-requiring patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: A randomized clinical trial was conducted at seven Veterans Affairs medical centers in 121 male patients with type 2 diabetes between the ages of 40 and 69 years receiving at least one injection of insulin per day and with HbA1c, levels of > or =8% at baseline. Weights, blood pressures, insulin use, and glucose monitoring data were obtained at each visit. Lipid levels were obtained at 0, 4, 8, and 12 months, and free and total insulin levels were obtained at 0, 6, and 12 months. All medications being taken were recorded at each visit. RESULTS: No difference in absolute blood pressure, neither systolic nor diastolic, was seen between patients receiving MDI or IIP therapy, but significantly more MDI patients required anti-hypertensive medications. When blood pressure was modeled against weight and time, IIP therapy was significantly better than MDI therapy for systolic blood pressure in patients with BMI <33 and for diastolic blood pressure in patients with BMI >34 kg/m2. Total cholesterol levels decreased in the overall sample, but IIP patients exhibited significantly higher levels than MDI patients. Triglyceride levels increased over time for both groups, with IIP patients having significantly higher levels than patients in the MDI group. BMI was a significant predictor of, and inversely proportional to, HDL cholesterol level. No difference in lipid-lowering drug therapy was seen between the two groups. Free insulin and insulin antibodies tended to decrease in the IIP group as compared with the MDI group. C-peptide levels decreased in both groups. CONCLUSIONS: IIP therapy in insulin-requiring patients with type 2 diabetes has advantages over MDI therapy in decreasing the requirement for antihypertensive therapy and for decreasing total and free insulin and insulin antibodies. Both therapies reduce total cholesterol and C-peptide levels. 相似文献
62.
MC Teixeira WC Nahas E Mazucchi LE Ianhez E David-Neto 《Canadian Metallurgical Quarterly》1998,13(8):2092-2097
BACKGROUND: The unregulated renin release by native kidneys is one of the factors responsible for the high incidence of hypertension after renal transplantation but, even after three decades of transplantation, there is still a lack of a method to identify it as the major cause of hypertension. METHODS: We investigated whether or not peripheral renin activity, before and 90 min after 25 mg of captopril, can play this role. One hundred and five consecutive patients with SCr less than 2 mg/dl were studied 18 +/- 8 months after renal transplantation. Forty-seven of them were considered hypertensive and 58 normotensive. All hypertensive patients were submitted to the captopril test to analyse the peripheral renin activity profile. RESULTS: In the hypertensive group, 17 patients (36%) were considered Renin-pos and 30 (64%) Renin-neg. All Renin-pos (stimulated renin = 19.1 +/- 6.4 ng/ml/h) patients were submitted to bilateral nephrectomy (bNx) and re-evaluated 6 months later. All of them normalized renin activity (4.4 +/- 3.0 ng/ml/h, P = 0.0001) and 10 of 17 (60%) became normotensive and off drugs. The remaining seven (40%) decreased the number of hypotensive drugs from 2.2 +/- 0.5 to 0.5 +/- 0.7/pt/day. There was a correlation between b-Renin and dBP (r = 0.47, P < 0.05) which was lost after bNx. An 'in situ' renal-cell carcinoma was found in two cases. Serum creatinine did not change. CONCLUSIONS: This study shows that the unregulated renin-angiotensin system from the native kidneys plays a major role in the maintenance of hypertension in some patients with normal graft function and that peripheral renin activity can identify those who will benefit from bilateral nephrectomy. 相似文献
63.
PURPOSE: A procedure using transvaginal sonohysterography (SHG) to perform operative intrauterine biopsies and resections is described. METHODS: Seven women, six with intrauterine pathology noted on diagnostic SHG and one with a thickened endometrium noted on transvaginal ultrasonography, underwent attempted operative SHG. The indications were peri- and postmenopausal bleeding (n = 4) and infertility requiring assisted reproduction (n = 3). Access to the uterine cavity was accomplished with a 9-F cervical access catheter (CAC) with a 3-ml balloon (BEI Medical Systems, ZSI Gynecology Products Division, Chatsworth, CA), which was placed in the cervical canal or lower uterine segment. Depending on the position of the noted uterine pathology, a 6-F uterine ostial access catheter (UOAC) (BEI Medical Systems, ZSI Gynecology Products Division) was placed through the CAC. The uterine cavity was distended with 5-10 ml of 1% Lidocaine and a 3-F loop grasper or finger-like biopsy grasper was then passed through the UOAC or a 5-F operative instrument directly within the CAC with attempted resection under ultrasound guidance. Biopsied samples were sent to pathology for definitive diagnosis. Office hysteroscopy was then performed to confirm adequate resection. RESULTS: Three of six patients had adequate resection or biopsy of intrauterine pathology, while the seventh patient successfully had a directed biopsy of the fundal cavity under ultrasound guidance. In one case, the visualized lesion could not be grasped. In the other two cases, each patient had severe cervical stenosis and declined in-office cervical dilation precluding the procedure. Each procedure was well tolerated, with an average time from start to finish of about 25 min (range, 18-43 min) without complications. CONCLUSIONS: Operative SHG makes it possible to resect and biopsy intrauterine pathology often missed on Pipelle sampling. If found to be as effective as hysteroscopy, operative SHG would provide a cost-effective alternative. Further study is ongoing to perfect the existing instruments to allow removal of larger lesions both safe and possible. 相似文献
64.
BACKGROUND: Skin manifestations have been described in 25% of patients with Mycoplasma pneumoniae infection. CASE REPORT: We report a case of Mycoplasma pneumoniae infection in a 29-year-old man who developed a polymorphous erythema-like reaction. Skin manifestations were associated with voluminous lymph node enlargement and high eosinophil levels both in serum and alveolar lavage. Seroconversion against Mycoplasma pneumoniae IgG was documented with ELISA. The clinical course was favorable with erythromycin. DISCUSSION: ELISA IgG seroconversion is sufficient to confirm the diagnosis of Mycoplasma pneumoniae infection as this test has an 80-90% specificity. This case was unusual by its clinical presentation and high eosinophil counts in serum and tissue samples, similar to what is found in drug-induced hypersensitivity. 相似文献
65.
KL Liew CS Choong PN Liu DH Tsai LH Chen WC Yang 《Canadian Metallurgical Quarterly》1998,61(8):488-491
Pyomyositis is a primary infection of skeletal muscle. We report the case of a previously healthy six-year-old who suffered from pyomyositis in the right lower back. He presented with lower back pain and low-grade fever for one week. After a series of laboratory and imaging studies, the diagnosis of right multifidus muscle pyomyositis with abscess formation was made. The patient recovered rapidly after incision and drainage therapy, accompanied by antibiotic treatment. Methicillin-resistant Staphylococcus aureus was cultured from the abscess discharge. It was strongly suspected that herbal medicines and common cold medication the patient had been prescribed before admission to our hospital produced a masking effect that delayed the diagnosis. 相似文献
66.
The nutritional status of 75 maintenance hemodialysis (MHD) patients was evaluated according to the dietary intake analysis, anthropometric measurements, biochemical and immunological parameters in this study. Furthermore, some possible factors which would affect nutritional status of hemodialysis patients were discussed. The results showed that hemodialysis patients demonstrated a high incidence of malnutrition. The low intake of protein and calorie, metabolic acidosis and inadequate dialysis would worsen the malnutrition while erythropoietin treatment improve the nutritional status of hemodialysis patients. Based on these results, suggestions were proposed for the improvement of nutritional status of MHD. 相似文献
67.
In the present study, the survival of cysticerci of Taenia solium in carcasses of 1 Small-Ear-Miniature and 2 Landrace Small-Ear-Miniature pigs kept in a refrigerator at 4 C was determined. The viability of the cysticerci was determined by observing evagination and active movement of the scolex under a fluorescent light after digestion in pig bile. Although no viable cysticerci were found after day 30, 58.8% cysticerci survived between day 26 and day 30. Moreover, more than 80% of the cysticerci were viable between day 1 and day 25. These findings indicate that taeniasis solium can be transmitted through eating raw or undercooked pork or viscera of pigs following refrigeration at 4 C for less than 30 days. 相似文献
68.
CF Chang LJ Kiser JE Bailey M Martins WC Gibson KA Schaberg DM Mirvis WB Applegate 《Canadian Metallurgical Quarterly》1998,279(11):864-869
In July 1996, Tennessee initiated a managed mental health and substance abuse program called TennCare Partners. This publicly funded "carve-out" experiment started chaotically and soon deteriorated into a crisis. Many patients did not receive care or lost continuity of care, and the traditional "safety net" mental health system nearly disintegrated. This qualitative case study sought to ascertain the impact of the TennCare Partners program. It points out that the program's difficulties stemmed directly from a flawed design that spread funds previously earmarked for severely mentally ill patients across the entire Medicaid population. States contemplating similar reforms should strive to protect vulnerable patients by risk-adjusting capitation payments and by focusing resources on care for severely mentally ill persons. States should also minimize program complexity and ensure the accountability of managed care networks for their patients' behavioral health care needs. 相似文献
69.
S Migliaccio S Bernardini WC Wetsel KS Korach T Faraggiana A Teti 《Canadian Metallurgical Quarterly》1998,63(5-6):352-354
Ventriculo-peritoneal shunts (VPS) are the most frequent operative procedures used to treat hydrocephalic children. Abdominal complications of VPS are now a rare event; however, their frequency varies from 5% to 47% according to reports. Anything that causes an obstruction or impediment of the VP derivation system will lead to intracranial hypertension, which requires immediate surgery. From 1985 to 1995 at the Division of Pediatric Surgery of the Federico II University of Naples, ten laparoscopies were performed in ten children with VPS complications. Cerebrospinal fluid pseudocysts were found in four infants. There was one case of abdominal wall perforation by the tip of the catheter at the umbilical level, two bowel obstructions, and one catheter was lost in the abdominal cavity. Finally, two children had malfunctioning of the peritoneal limb of the catheter. The laparoscopic technique was curative in all ten cases, thus avoiding a conventional laparotomy and the consequent risk of adhesions, which could cause further complications. 相似文献
70.
KE Lyons R Pahwa KL Busenbark AI Tr?ster S Wilkinson WC Koller 《Canadian Metallurgical Quarterly》1998,13(4):690-692
Deep brain stimulation (DBS) of the thalamus reduces tremor in patients with essential tremor (ET). However, few studies have determined the degree of improvement in daily functioning associated with DBS. We developed a self-report Tremor Activities of Daily Living Scale (TADLS) to compare daily functioning with the stimulator turned on and off. Patients rated their performance on the 30 items of the TADLS with the stimulator turned off and then on. They also performed 10 activities under the supervision of a clinician who rated their functional ability with stimulation off and then on. There was a 58% improvement in self-rated TADLS scores in patients with DBS with the stimulator on compared with stimulation off. When activities were rated by the clinician, the average improvement in functioning with the stimulator on was 54%. There were reasonably high correlations between patient and clinician ratings of functioning. ET patients have a marked improvement in daily functioning with thalamic DBS. 相似文献