全文获取类型
收费全文 | 2133篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 11篇 |
金属工艺 | 1篇 |
机械仪表 | 38篇 |
建筑科学 | 5篇 |
能源动力 | 1篇 |
轻工业 | 40篇 |
水利工程 | 1篇 |
无线电 | 5篇 |
一般工业技术 | 5篇 |
冶金工业 | 2010篇 |
原子能技术 | 6篇 |
自动化技术 | 7篇 |
出版年
2021年 | 2篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2013年 | 3篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 15篇 |
1999年 | 74篇 |
1998年 | 602篇 |
1997年 | 353篇 |
1996年 | 222篇 |
1995年 | 139篇 |
1994年 | 99篇 |
1993年 | 119篇 |
1992年 | 12篇 |
1991年 | 18篇 |
1990年 | 15篇 |
1989年 | 17篇 |
1988年 | 23篇 |
1987年 | 13篇 |
1986年 | 16篇 |
1985年 | 17篇 |
1984年 | 1篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 19篇 |
1980年 | 27篇 |
1978年 | 6篇 |
1977年 | 66篇 |
1976年 | 161篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1966年 | 2篇 |
1964年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有2134条查询结果,搜索用时 15 毫秒
991.
Current methods of determining the rotational diffusion tensors of proteins in solution by NMR spectroscopy exclusively utilize relaxation rate constants for backbone amide 15N spins. However, the distributions of orientations of N-H bond vectors are not isotropic in many proteins, and correlations between bond vector orientations reduce the accuracy and precision of rotational diffusion tensors extracted from 15N spin relaxation data. The inclusion of both 13C alpha and 15N spin relaxation rate constants increases the robustness of the diffusion tensor analysis because the orientations of the C alpha-H alpha bond vectors differ from the orientations of the N-H bond vectors. Theoretical and experimental results for calbindin D9k, granulocyte colony stimulating factor, and ubiquitin, three proteins with different distributions of N-H and C alpha-H alpha bond vectors, are used to illustrate the advantages of the simultaneous utilization of 13C alpha and 15N relaxation data. 相似文献
992.
A Gasparri A Sidoli LP Sanchez R Longhi AG Siccardi PC Marchisio A Corti 《Canadian Metallurgical Quarterly》1997,272(33):20835-20843
Although several functions have been suggested for chromogranin A, a glycoprotein secreted by many neuroendocrine cells, the physiological role of this protein and of its proteolytic fragments has not been established. We have found that mixtures of chromogranin A fragments can inhibit fibroblast adhesion. The anti-adhesive activity was converted into pro-adhesive activity by limited trypsin treatment. Pro-adhesive effects were observed also with recombinant N-terminal fragments corresponding to residues 1-78 and 1-115 and with a synthetic peptide encompassing the residues 7-57. These fragments induced adhesion and spreading of fibroblasts on plates coated with collagen I or IV, laminin, fetal calf serum (FCS) but not on bovine serum albumin. The long incubation time required for adhesion assays (4 h) and the FCS requirements for optimal adhesion suggest that the adhesive activity is likely indirect and requires other proteins present in the FCS or made by the cells. These findings suggest that chromogranin A and its fragments could play a role in the regulation of cell adhesion. Since chromogranin A is concentrated and stored within granules and rapidly released by neuroendocrine cells and neurons after an appropriate stimulus, this protein could be important for the local control of cell adhesion by stimulated cells. 相似文献
993.
OBJECTIVE: To assess the clinical effectiveness of an early discharge policy for patients with stroke by using a community based rehabilitation team. DESIGN: Randomised controlled trial to compare conventional care with an early discharge policy. SETTING: Two teaching hospitals in inner London. SUBJECTS: 331 medically stable patients with stroke (mean age 71) who lived alone and were able to transfer independently or who lived with a resident carer and were able to transfer with help. INTERVENTIONS: 167 patients received specialist community rehabilitation for up to 3 months after randomisation. 164 patients continued with conventional hospital and community care. MAIN OUTCOME MEASURES: Barthel score at 12 months. Secondary outcomes measured impairment with motoricity index, minimental state examination, and Frenchay aphasia screening test; disability with the Rivermead activity of daily living scales, hospital anxiety and depression scale, and 5 m walk; handicap with the Nottingham health profile; carer stress with caregiver strain index and patient and carer satisfaction. The main process measure was length of stay after randomisation. RESULTS: One year after randomisation no significant differences in clinical outcomes were found apart from increased satisfaction with hospital care in the community therapy group. Length of stay after randomisation in the community therapy group was significantly reduced (12 v 18 days; P < 0.0001). Patients with impairments were more likely to receive treatment in the community therapy group. CONCLUSIONS: Early discharge with specialist community rehabilitation after stroke is feasible, as clinically effective as conventional care, and acceptable to patients. Considerable reductions in use of hospital beds are achievable. 相似文献
994.
995.
996.
IV Volkova IR Losev VA Lemenkov AG Mushegov SV Mogil'nikov 《Canadian Metallurgical Quarterly》1996,(3):8-12
The paper describes a non-invasive oscillometric blood pressure (BP) measuring device. It provides an algorithm for the automatic measurement of systolic and diastolic BP values. A variant of assessing the BP measurement stability is proposed and the results of this assessment are given for 3 devices made by different firms. The total errors made by the studied device that functions as part of a physician's computer monitor are defined. Health institutions, resuscitation units, operating rooms for children and adults are an application sphere of the device. 相似文献
997.
AR Localio SL Weaver JR Landis AG Lawthers TA Brenhan L Hebert TJ Sharp 《Canadian Metallurgical Quarterly》1996,125(6):457-464
Forty critically ill adult patients with severe Gram-negative infection were treated with once-daily amikacin combined with ceftazidime. The mean age was 56.6 +/- 19 years and mean APACHE II score was 22.7 +/- 6.6. Forty percent of patients required mechanical ventilation. The mean creatinine clearance at onset of therapy was 59.4 +/- 28 ml/min. All bacterial isolates were sensitive to amikacin. Fixed doses of amikacin 15 mg/kg, 12 mg/kg, and 8 mg/kg body weight were given once daily to patients with estimated creatinine clearance of > 80 ml/min., 50-80 ml/min., and < 50 ml/min, respectively. Forty-two causative gram-negative bacteria were isolated from 40 patients. The most common bacteria were Pseudomonas aeruginosa (18), and Escherichia coli (10). Overall clinical success and bacteriological eradication occurred in 85% and 87.5% of patients; 78.9% and 79% of patients with hospital-acquired infections; 90.5% and 95.2% of patients with community-acquired infections; and 62.5% and 81.3% of patients requiring mechanical ventilation, respectively. Therapeutic failure was documented in 15% of patients. Death due to infection was scored in two patients. The remaining were all due to persistence of the initial causative bacteria in patients with hospital-acquired infections. Persistence was documented with Ps. aeruginosa (2), Serratia spp. (1), and Acinetobacter spp. (1). Overall mortality occurred in 22.5% patients. Death unrelated to infection occurred in 7 patients. There was no clinical evidence of ototoxicity in any of our patients, however, nephrotoxicity was documented in 5%. In conclusion, once-daily amikacin combined with ceftazidime is practical, efficacious and probably safe in critically ill infected patients. 相似文献
998.
AG Aya M Hoffet R Mangin JP Balducchi JJ Eledjam 《Canadian Metallurgical Quarterly》1996,174(5):1659-1660
A patient with a history of drug abuse and histologically diagnosed hepatitis B-related polyarteritis nodosa was admitted for severe hypertension. After a cesarean section because of worsening of her clinical status with severe proteinuria and edema, she improved dramatically. No sign of acute polyarteritis nodosa occurred. 相似文献
999.
U Boggi P Viacava AG Naccarato PC Giulianotti G di Candio L Battolla F Mosca 《Canadian Metallurgical Quarterly》1997,44(14):398-407
Although liposarcoma is the second most common soft-tissue sarcoma in adults, its incidence within the gastrointestinal tract is distinctly low. Esophageal involvement is exceedingly rare and only four cases have been described so far. A fifth case is presented here along with a thorough review of the literature of polypoid lipomatous tumors of the esophagus. Diagnostic and therapeutical strategies of these tumors are discussed in detail. 相似文献
1000.
AL Cherniaev OM Grobova GV Nekliudova AG Chuchalin SP Ammosova PG Pleshanov OA Liaskina VP Chernikov 《Canadian Metallurgical Quarterly》1998,60(5):36-41
Tuberculosis is an ancient disease which has had a resurgence in the United States. Many elderly clients were exposed to tuberculosis as children and young adults and are still carrying the infection today. This article describes tuberculosis as it affects the elderly client in community and nursing home settings. The history, etiology, clinical manifestations, treatment, and prevention of tuberculosis infection and disease are presented. Because nurses can be very instrumental in controlling tuberculosis in the elderly, gerontological nursing implications are discussed. 相似文献