全文获取类型
收费全文 | 10778篇 |
免费 | 8篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 109篇 |
金属工艺 | 3篇 |
机械仪表 | 11篇 |
建筑科学 | 16篇 |
矿业工程 | 12篇 |
能源动力 | 5篇 |
轻工业 | 43篇 |
水利工程 | 6篇 |
石油天然气 | 2篇 |
无线电 | 52篇 |
一般工业技术 | 46篇 |
冶金工业 | 10433篇 |
原子能技术 | 4篇 |
自动化技术 | 53篇 |
出版年
2021年 | 3篇 |
2019年 | 4篇 |
2016年 | 7篇 |
2014年 | 6篇 |
2013年 | 30篇 |
2012年 | 16篇 |
2011年 | 11篇 |
2010年 | 22篇 |
2009年 | 13篇 |
2008年 | 16篇 |
2007年 | 13篇 |
2006年 | 19篇 |
2005年 | 20篇 |
2004年 | 15篇 |
2003年 | 29篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 12篇 |
1999年 | 306篇 |
1998年 | 3377篇 |
1997年 | 1962篇 |
1996年 | 1205篇 |
1995年 | 685篇 |
1994年 | 548篇 |
1993年 | 637篇 |
1992年 | 69篇 |
1991年 | 138篇 |
1990年 | 122篇 |
1989年 | 130篇 |
1988年 | 145篇 |
1987年 | 104篇 |
1986年 | 95篇 |
1985年 | 68篇 |
1984年 | 8篇 |
1983年 | 16篇 |
1982年 | 51篇 |
1981年 | 50篇 |
1980年 | 72篇 |
1979年 | 6篇 |
1978年 | 35篇 |
1977年 | 199篇 |
1976年 | 467篇 |
1975年 | 18篇 |
1974年 | 4篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1965年 | 3篇 |
1955年 | 8篇 |
1954年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
JM Robbins 《Canadian Metallurgical Quarterly》1989,40(4):2128-2136
95.
96.
97.
98.
JM Muche A Lukowsky K Asadullah S Gellrich W Sterry 《Canadian Metallurgical Quarterly》1997,90(4):1636-1642
Clonal T cells have been demonstrated in skin lesions of all stages of cutaneous T-cell lymphomas (CTCLs). However, there are conflicting data regarding the CTCL stage at which dissemination of clonal cells into peripheral blood occurs. Although the multifocal occurrence of cutaneous CTCL lesions and T-cell recirculation suggest an early appearance of neoplastic cells in the blood, circulating clonal T cells have only been detected in advanced stages. We investigated their occurrence by a highly sensitive polymerase chain reaction (PCR) assay amplifying T-cell receptor gamma rearrangements and subsequent heteroduplex temperature gradient gel electrophoresis (HD-TGGE) of the amplification products. Circulating clonal T cells were found in 26 of 45 patients with mycosis fungoides (MF), six of seven with Sezary's syndrome (SS), 10 of 13 pleomorphic CTCLs, and three of four unclassified CTCLs. Corresponding skin specimens carried clonal T cells in 29 of 40 MF, three of four SS, 12 of 12 pleomorphic, and two of two unclassified CTCL patients. Except for the blood specimen of a psoriatic patient, all samples of 60 controls (psoriasis vulgaris, atopic dermatitis, and healthy volunteers) revealed polyclonal amplification products. In 30 of 32 CTCL patients carrying a clonal rearrangement in blood and skin, identity of both clones was indicated by HD-TGGE and confirmed by sequencing six of these cases. We found an unexpected high frequency of identical clonal T cells in peripheral blood and skin of CTCL patients, including early stages of MF. This supports the concept of an early systemic disease in CTCL and raises new questions concerning the pathogenesis. 相似文献
99.
CE Alpers CC Tsai KL Hudkins Y Cui L Kuller RE Benveniste JM Ward WR Morton 《Canadian Metallurgical Quarterly》1997,13(5):413-424
Focal and segmental glomerulosclerosis (FSG) with endothelial tubuloreticular inclusions (TRIs) is the typical lesion of human HIV-associated glomerulopathy. Autopsy studies showed the presence of FSG in 3 of 15 macaques dying 15-120 weeks after experimental infection with a simian immunodeficiency virus (SIVMne). Ultrastructural studies generally revealed numerous endothelial TRIs (also present in normals), mesangial expansion, and evidence of mesangial cell injury. One additional animal had a small-vessel polyarteritis with a proliferative and focally crescentic glomerulonephritis; seven animals had mild, multifocal interstitial nephritis. All animals had documented viremia after infection; 14 of 15 developed antibodies to SIV postinoculation. Additional postmortem findings included severe enterocolitis, encephalitis, and opportunistic infections. In contrast, autopsy studies of macaques infected with a type D simian retrovirus (SAIDS-D/Washington, SRV-2) for similar periods of time (n = 40) showed no evidence of FSG. One SRV-infected animal had a mild proliferative glomerulonephritis. These studies indicate SIV-infected primates may provide a relevant model for study of human HIV-associated nephropathy. They also indicate the variable pathology that can be seen in primate infections of distinct retrovirus types, each of which produces a simian immunodeficiency state that resembles human AIDS. 相似文献
100.
The high prevalence of multiple chronic medical conditions in the elderly and the likelihood of multiple drug therapies dramatically increase the chance of drug-specific adverse effects and drug-drug interactions. This article reviews the age-associated alterations in pharmacokinetics and pharmacodynamics along with the most frequently prescribed medications for the elderly. Adverse drug reactions, drug-drug interactions and oral side effects are reviewed along with the impact these medications may have on dental treatment planning and management. 相似文献