全文获取类型
收费全文 | 1840篇 |
免费 | 0篇 |
专业分类
化学工业 | 6篇 |
机械仪表 | 1篇 |
建筑科学 | 4篇 |
轻工业 | 6篇 |
水利工程 | 1篇 |
冶金工业 | 1819篇 |
自动化技术 | 3篇 |
出版年
2022年 | 1篇 |
2014年 | 2篇 |
2013年 | 1篇 |
2012年 | 1篇 |
2011年 | 1篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2003年 | 4篇 |
1999年 | 44篇 |
1998年 | 541篇 |
1997年 | 273篇 |
1996年 | 199篇 |
1995年 | 112篇 |
1994年 | 92篇 |
1993年 | 103篇 |
1992年 | 18篇 |
1991年 | 29篇 |
1990年 | 24篇 |
1989年 | 36篇 |
1988年 | 37篇 |
1987年 | 31篇 |
1986年 | 33篇 |
1985年 | 18篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 21篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 55篇 |
1976年 | 126篇 |
1975年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1840条查询结果,搜索用时 218 毫秒
91.
92.
93.
IM McMorrow CA Comrack PP Nazarey DH Sachs H DerSimonian 《Canadian Metallurgical Quarterly》1997,64(3):546-549
BACKGROUND: The terminal Gal alpha1,3Galactose (alphaGal) determinant is present on all porcine glycoproteins and glycolipids, but is not expressed by human cells. Consequently human sera contain anti-alphaGal natural antibodies. The human blood group B antigen [Gal alpha1,3(Fuc1,2)Galactose] is differentiated from the alphaGal epitope by the presence of a fucosyl group. METHODS: To determine whether the expression of the B antigen has any effect on the level of alphaGal-reactive natural antibodies, equal numbers (n=12) of A, B, AB, and O serum samples were evaluated by ELISA and flow cytometry. RESULTS: A significant reduction in IgG alphaGal reactivity was observed with serum samples from B antigen-expressing donors (B, AB) relative to non-B antigen-expressing donors (A, O). CONCLUSIONS: These results are consistent with the possibility that anti-alphaGal antibodies in non-B antigen-expressing individuals include a subset that is reactive with the structurally related B antigen and that this subset is absent in B and AB individuals. 相似文献
94.
95.
JC Lovejoy SR Smith GA Bray JP DeLany JC Rood D Gouvier M Windhauser DH Ryan R Macchiavelli R Tulley 《Canadian Metallurgical Quarterly》1997,82(3):765-770
OBJECTIVE: To conceptualize, with fine needle aspiration cytology (FNAC), the early cellular events occurring in and around fresh autogenous and allogenic bone grafts during the first 40 postimplantation days. STUDY DESIGN: Forty-eight cases of bone grafts were studied by FNAC at serial intervals of 10, 20, 30 and 40 postimplantation days. Twenty patients were recipients of autogenous grafts, 16 received 0.6N HCI partially decalcified allogenic bone implants, and 4 received combined autogenous and allogenic bone grafts (included in the allograft group). There were eight control cases of closed fracture shaft femur, which were managed conservatively. RESULTS: The initial cellular responses in autogenous grafts, allografts and controls appear to be a part of the nonspecific reparative process followed by a more specific phase, with a steady increase in relative lymphocyte count from the 20th day onwards. Osteogenesis, as judged by osteoblasts and osteoclasts, was also comparable. CONCLUSION: Partially decalcified allografts appear to be a good substitute for autogenous bone grafts in clinical practice when adequate autogenous material is not available. FNAC is a good technique for studying bone graft responses without interfering with graft uptake. It is helpful in the early detection of subclinical infection or any other pathology at the graft site. 相似文献
96.
J Hitti DH Watts SK Burchett T Schacker S Selke ZA Brown L Corey 《Canadian Metallurgical Quarterly》1997,177(2):450-454
OBJECTIVE: Our purpose was to determine whether pregnant women infected with human immunodeficiency virus-1 have an increased risk of herpes simplex virus-2 seropositivity and herpes simplex virus reactivation at delivery. STUDY DESIGN: Sixty women infected with human immunodeficiency virus and 8408 other patients who were delivered at the University of Washington between 1989 and 1995 had herpes simplex virus serologic determinations at delivery. Genital herpes simplex virus cultures were obtained for 48 (80%) of the human immunodeficiency virus-infected women and 5567 (66%) of the controls. Logistic regression was used to adjust for possible confounding factors. RESULTS: Forty-five (75%) of human immunodeficiency virus-infected women and 2709 (32%) controls were seropositive for herpes simplex virus-2 (p < 0.0001). Eight percent of human immunodeficiency virus-infected women and 2% of controls had herpes simplex virus reactivation in labor (p < 0.05). CONCLUSIONS: Infection with herpes simplex virus-2 is common among pregnant women infected with human immunodeficiency virus. Herpes simplex virus reactivation complicates labor in this group more often than in other obstetric patients. The role of herpes simplex virus in perinatal human immunodeficiency virus transmission warrants further study. 相似文献
97.
98.
99.
Modification of arginine residues in bradykinin, [1-5]-bradykinin, splenopentin and two synthetic pentapeptides with acetylacetone (pentane-2,4-dione) significantly increases the relative abundance of sequence-specific fragment ions produced by matrix-assisted laser desorption/ionization (MALDI). The fragmentation efficiency as measured by post-source decay in a reflectron time-of-flight mass spectrometer increases by a factor of 2-3.5. Peptide bonds adjacent to modified residues are more susceptible to cleavage than in the non-derivatized peptide ions. The increased lability of these bonds gives rise to more complete sequence information. In addition, the relative abundances of sequence-specific fragment ions are enhanced. This strategy makes it possible to obtain valuable structural information from arginine-containing peptides that otherwise do not fragment well. 相似文献
100.
In the patients with invasion to the aortic window, we performed operation via median sternotomy combined with anteroaxillar thoracotomy. In such patients with T4 invasion, conventional pneumonectomy could not be performed because of the extensive invasion near the main pulmonary artery trunk. In these patients in this study, complete resection of the involved pulmonary artery could be performed using a vascular clamp without CP bypass. Operative technique was as follows: first, the pericardium was opened and taping of the aorta was applied. When the uninvolved part of the intrapericardial pulmonary artery was long enough to cut, we could use a stapling device, but the stapling device could not be used in many cases because the length of the uninvolved segment was too short to cut the left pulmonary artery. In order to carry out complete resection, it was necessary to clamp the central part of the main pulmonary artery diagonally from the left lower side to the right upper side. The pulmonary arterial stump was closed with continuous 4-0 monofilament mattress and over and over suture. We recommend an aggressive surgical approach for the tumor with invasion to the aortic window, because the prognosis is dismal in nonresected locally advanced lung cancer. 相似文献