全文获取类型
收费全文 | 2615篇 |
免费 | 19篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 8篇 |
综合类 | 1篇 |
化学工业 | 215篇 |
金属工艺 | 7篇 |
机械仪表 | 20篇 |
建筑科学 | 43篇 |
矿业工程 | 2篇 |
能源动力 | 14篇 |
轻工业 | 67篇 |
水利工程 | 6篇 |
无线电 | 93篇 |
一般工业技术 | 154篇 |
冶金工业 | 1944篇 |
原子能技术 | 6篇 |
自动化技术 | 55篇 |
出版年
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 5篇 |
2017年 | 10篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 9篇 |
2013年 | 50篇 |
2012年 | 13篇 |
2011年 | 26篇 |
2010年 | 25篇 |
2009年 | 22篇 |
2008年 | 19篇 |
2007年 | 22篇 |
2006年 | 30篇 |
2005年 | 16篇 |
2004年 | 23篇 |
2003年 | 26篇 |
2002年 | 17篇 |
2001年 | 15篇 |
2000年 | 23篇 |
1999年 | 70篇 |
1998年 | 642篇 |
1997年 | 355篇 |
1996年 | 202篇 |
1995年 | 133篇 |
1994年 | 98篇 |
1993年 | 141篇 |
1992年 | 28篇 |
1991年 | 41篇 |
1990年 | 39篇 |
1989年 | 31篇 |
1988年 | 34篇 |
1987年 | 26篇 |
1986年 | 33篇 |
1985年 | 33篇 |
1984年 | 14篇 |
1983年 | 21篇 |
1982年 | 28篇 |
1981年 | 29篇 |
1980年 | 25篇 |
1979年 | 13篇 |
1978年 | 19篇 |
1977年 | 40篇 |
1976年 | 70篇 |
1975年 | 15篇 |
1974年 | 6篇 |
1973年 | 8篇 |
1970年 | 7篇 |
排序方式: 共有2635条查询结果,搜索用时 890 毫秒
941.
A 23-year old woman with primary sclerosing cholangitis was being treated with ursodeoxycholic acid (URSO). When pregnancy was diagnosed, she was already through the first trimester. The treatment was discontinued, but her symptoms including severe pruritus recurred immediately, and the biochemical markers of bile duct obstruction worsened. It was necessary to start URSO-treatment again, which relieved her symptoms and improved the biochemistry. The remaining part of the pregnancy was uncomplicated, there were no malformations and so far, the baby is doing fine. URSO may be a possible treatment for severe intrahepatic cholestasis and pruritus during pregnancy. 相似文献
942.
Reliability information provided by sets of orthogonal check sums in a majority logic decoder for block codes is used in a type-I hybrid automatic-repeat-request (ARQ) error control scheme. The reliability information is obtained through a simple modification of the majority logic decoding rule. It is shown that the reliability performance of Reed-Muller and other majority logic decodable codes can be substantially improved at the expense of a very small reduction in throughput. The simplicity of the decoding circuit permits implementation in systems with very high data rates 相似文献
943.
944.
JX Yan L Tonella JC Sanchez MR Wilkins NH Packer AA Gooley DF Hochstrasser KL Williams 《Canadian Metallurgical Quarterly》1997,18(3-4):491-497
The cellular slime mold Dictyostelium discoideum is a eukaryotic microorganism which has developmental life stages attractive to the cell and molecular biologist. By displaying the two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) protein map of different developmental stages, the key molecules can be identified and characterised, allowing a detailed understanding of the D. discoideum proteome. Here we describe the preparation of reference gel of the D. discoideum multicellular aggregate, the slug. Proteins were separated by 2-D PAGE with immobilised pH gradients (pH 3.5-10) in the first dimension and sodium dodecyl sulfate (SDS)-PAGE in the second dimension. Micropreparative gels were electroblotted onto polyvinylidene difluoride (PVDF) membranes and 150 spots were visualised by amido black staining. Protein spots were excised and 31 were putatively identified by matching their amino acid composition, estimated isoelectric point (pI) and molecular weight (M(r)) against the SWISS-PROT database with the ExPASy AAcompID tool (http:// expasy.hcuge.ch/ch2d/aacompi.html). A total of 25 proteins were identified by matching against database entries for D. discoideum, and another six by cross-species matching against database entries for Saccharomyces cerevisiae proteins. This map will be available in the SWISS-2DPAGE database. 相似文献
945.
946.
High compression of sorbent powders promotes flow uniformity and reduces interstitial porosity. These features were exploited in a radial flow configuration to show that good peak resolution was possible for applications to analytical chromatography. An exact analytical solution was uncovered to predict the transient response of an elementary pulse of solute in a flowing inert gas. Experiments on the system methane on alumina are compared quite favorably with theory, showing that the key dissipative force for band broadening is radial diffusion 相似文献
947.
948.
Melan-A/MART-1 is a melanoma differentiation antigen that is recognized by a high proportion of cytolytic T lymphocyte (CTL) clones derived from human leukocyte antigen (HLA)-A2+ melanoma patients. Whereas peptide Melan-A/ MART-1(27-35) was originally defined as the immunodominant CTL epitope, we have previously reported that peptide Melan-A/MART-1(26-35) was recognized more efficiently by the majority of tumor-reactive CTL clones. As demonstrated here, CTL populations generated from blood lymphocytes of either melanoma patients or healthy individuals after in vitro stimulation with peptide Melan-A/MART-1(26-35) killed specifically HLA-A2+ Melan-A+ allogeneic melanoma cells, thus suggesting their potential use in adoptive immunotherapy. We characterized the surface phenotype of the circulating CTL precursors (CTLp), which respond to in vitro stimulation with peptide Melan-A/MART-1(26-35). In melanoma patients, these CTLp predominantly expressed the CD45RO memory marker. In contrast, they were mainly, although not exclusively, found in the CD45RA subpopulation of CD8 T cells in healthy individuals. The demonstration that Melan-A/MART-1-specific CTLp in peripheral blood lymphocytes from HLA-A2+ patients with metastatic melanoma express a memory phenotype provides direct evidence that in vivo priming of this antigen may occur during tumor progression. 相似文献
949.
GJ Okano KL Rascati JP Wilson DD Remund JD Grabenstein DI Brixner 《Canadian Metallurgical Quarterly》1997,19(6):1433-45; discussion 1424-5
950.
JM Lawrence TL Moore TG Osborn G Nesher KL Madson MB Kinsella 《Canadian Metallurgical Quarterly》1993,22(4):265-274
Early studies showed few immunologic abnormalities in juvenile rheumatoid arthritis (JRA) patients. There were no specific laboratory markers useful for diagnosis and assessment of the course of disease in JRA. Previous work showed an association of antinuclear antibodies (ANA) with early-onset pauciarticular disease and iridocyclitis. Similarly, the presence of 19S immunoglobulin (Ig) M rheumatoid factors (RF) was associated with late-onset polyarticular disease in girls. More recent studies have detected many unique autoantibodies. Newer assays show 19S IgM RF in up to 35% of JRA patients, although still mainly in girls with late-onset polyarticular disease. Hidden 19S IgM RF can be shown in up to 75% of JRA patients using different procedures, primarily in those with active polyarticular-or pauciarticular-onset disease. Immune complexes have been detected in JRA patients by means of different techniques; their presence usually correlates with active disease. Studies on a specific ANA in JRA have shown no common extractable nuclear antigen, but antihistone antibodies have been found in up to 75% of cases, again mainly in those with pauciarticular onset and iritis. Finally, a variety of unusual immunologic proteins have also been detected, including anti-ocular, anti-cellular, anti-cardiolipin, anti-perinuclear factor, and anti-collagen antibodies. This review evaluates the significance of these antibodies that can now be found in JRA. 相似文献