全文获取类型
收费全文 | 1825篇 |
免费 | 26篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 101篇 |
金属工艺 | 14篇 |
机械仪表 | 18篇 |
建筑科学 | 25篇 |
矿业工程 | 5篇 |
能源动力 | 16篇 |
轻工业 | 29篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 31篇 |
一般工业技术 | 72篇 |
冶金工业 | 1450篇 |
自动化技术 | 77篇 |
出版年
2023年 | 8篇 |
2022年 | 5篇 |
2021年 | 20篇 |
2020年 | 13篇 |
2019年 | 19篇 |
2018年 | 16篇 |
2017年 | 11篇 |
2016年 | 19篇 |
2015年 | 21篇 |
2014年 | 20篇 |
2013年 | 24篇 |
2012年 | 22篇 |
2011年 | 36篇 |
2010年 | 21篇 |
2009年 | 24篇 |
2008年 | 21篇 |
2007年 | 10篇 |
2006年 | 11篇 |
2005年 | 13篇 |
2004年 | 14篇 |
2003年 | 14篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 7篇 |
1999年 | 46篇 |
1998年 | 468篇 |
1997年 | 258篇 |
1996年 | 172篇 |
1995年 | 91篇 |
1994年 | 72篇 |
1993年 | 72篇 |
1992年 | 10篇 |
1991年 | 32篇 |
1990年 | 13篇 |
1989年 | 22篇 |
1988年 | 23篇 |
1987年 | 14篇 |
1986年 | 9篇 |
1985年 | 23篇 |
1983年 | 4篇 |
1982年 | 10篇 |
1981年 | 2篇 |
1980年 | 14篇 |
1978年 | 8篇 |
1977年 | 32篇 |
1976年 | 65篇 |
1975年 | 5篇 |
1971年 | 1篇 |
1963年 | 2篇 |
1940年 | 1篇 |
排序方式: 共有1851条查询结果,搜索用时 15 毫秒
1.
The in vitro drug sensitivity of three dihydrofolate reductase inhibitors (pyrimethamine, cycloguanil, trimethoprim) was determined against 29 strains and isolates of Plasmodium falciparum by an isotopic semi-microtest. Trimethoprim is less active than pyrimethamine or cycloguanil and its activity is correlated with that of two other inhibitors, suggesting cross-resistance in vitro among the dihydrofolate reductase inhibitors. 相似文献
2.
The purpose of this study was to identify the optimal knot construction for interrupted dermal sutures. A synthetic braided absorbable suture, sizes 3-0 and 5-0, was selected for this evaluation. With reproducible mechanical performance tests, we determined that the construction of secure knots without ears required one additional throw as compared with secure knots with 3-mm ears. The direction of applied tension did not alter knot security, with the exception of granny knots, which required an extra throw when tension was applied parallel to the suture loop. Because interrupted dermal knot construction is accomplished without knot ears and with an applied tension parallel to the wound, one additional throw must be added to the knot to ensure knot security. 相似文献
3.
4.
Hannes Verlinde Martine De Cock Raymond Boute 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2006,36(3):679-684
As opposed to quantitative association rule mining, fuzzy association rule mining is said to prevent the overestimation of boundary cases, as can be shown by small examples. Rule mining, however, becomes interesting in large databases, where the problem of boundary cases is less apparent and can be further suppressed by using sensible partitioning methods. A data-driven approach is used to investigate if there is a significant difference between quantitative and fuzzy association rules in large databases. The influence of the choice of a particular triangular norm in this respect is also examined. 相似文献
5.
The miscibility and phase behavior of ternary blends containing dimethylpolycarbonate (DMPC), tetramethylpolycarbonate (TMPC) and poly[styrene‐co‐(methyl methacrylate)] copolymer (SMMA) have been explored. Ternary blends containing polystyrene (PS) instead of SMMA were also examined. Blends of DMPC with SMMA copolymers (or PS) did not form miscible blends regardless of methyl methacrylate (MMA) content in copolymers. However, DMPC blends with SMMA (or PS) blends become miscible by adding TMPC. The miscible region of ternary blends is compared with the previously determined miscibility region of binary blends having the same chemical components and compositions. The region where the ternary blends are miscible is much narrower than that of binary blends. Based on lattice fluid theory, the observed phase behavior of ternary blends was analyzed. Even though the term representing the Gibbs free energy change of mixing for certain ternary blends had a negative value, blends were immiscible. It was revealed that a negative value of the Gibbs free energy change of mixing was not a sufficient condition for miscible ternary blends because of the asymmetry in the binary interactions involved in ternary blends. Copyright © 2004 Society of Chemical Industry 相似文献
6.
7.
8.
We present a technique for in situ lens nucleus emulsification using low phaco power and high vacuum, a continuous curvilinear capsulorhexis, and hydrodelineation. Emulsification is done with the phaco tip slanted down 30 or 45 degrees. Cutting and aspiration do not cause an undesirable energy loss. This technique can be combined with the nuclear chopping or divide and conquer methods because of its ability to drill and hold the nucleus. Posterior capsular rupture is prevented because the separated epinucleus acts as a barrier between the nucleus and the cortex. The low power used minimizes the energy transfer to the corneal endothelium. This technique is particularly useful in eyes with brunescent cataract. 相似文献
9.
WI Bensinger KS Schiffman L Holmberg FR Appelbaum R Maziarz P Montgomery E Ellis S Rivkin P Weiden K Lilleby S Rowley S Petersdorf JP Klarnet W Nichols A Hertler R McCroskey CH Weaver CD Buckner 《Canadian Metallurgical Quarterly》1997,19(12):1183-1189
The purpose of this study was to determine the outcome of patients with metastatic breast cancer treated with high-dose busulfan (Bu), melphalan (Mel) and thiotepa (TT) followed by peripheral blood stem cell (PBSC) infusion. Fifty-one patients with chemotherapy refractory (n = 32) or responsive (n = 19) metastatic breast cancer received Bu (12 mg/kg), Mel (100 mg/m2) and TT (500 mg/m2) followed by PBSC collected after chemotherapy and growth factor (n = 43) or growth factor alone (n = 8). The 100 day treatment-related mortality was 8% including one death from cytomegalovirus pneumonia, one from aspiration pneumonia and two from regimen-related toxicity (RRT). Seven of 28 refractory (25%) and 5/7 (71%) responsive patients with evaluable disease achieved a complete response of all measurable disease or all soft tissue disease with at least improvement in bone lesions (PR*). Fifteen of 51 patients (29%) are alive and progression-free a median of 423 days (range 353-934) after treatment, 5/32 (16%) with refractory disease and 10/19 (53%) with responsive disease. The probabilities of progression-free survival (PFS) at 1.5 years for the patients with refractory (n = 32) and responsive (n = 19) disease were 0.24 and 0.53, respectively. These preliminary data suggest that high-dose Bu/Mel/TT has significant activity in patients with advanced breast cancer and may be superior to some previously published regimens. 相似文献
10.
CK Damer J Partridge WR Pearson TA Haystead 《Canadian Metallurgical Quarterly》1998,273(38):24396-24405
Microcystin-affinity chromatography was used to purify 15 protein phosphatase 1 (PP1)-binding proteins from the myofibrillar fraction of rabbit skeletal muscle. To reduce the time and amount of material required to identify these proteins, proteome analysis by mixed peptide sequencing was developed. Proteins are resolved by SDS-polyacrylamide gel electrophoresis, electroblotted to polyvinylidene fluoride membrane, and stained. Bands are sliced from the membrane, cleaved briefly with CnBr, and applied without further purification to an automated Edman sequencer. The mixed peptide sequences generated are sorted and matched against the GenBank using two new programs, FASTF and TFASTF. This technology offers a simple alternative to mass spectrometry for the subpicomolar identification of proteins in polyacrylamide gels. Using this technology, all 15 proteins recovered in PP-1C affinity chromatography were sequenced. One of the proteins, PP-1bp55, was homologous to human myosin phosphatase, MYPT2. A second, PP-1bp80, identified in the EST data bases, contained a putative PP-1C binding site and a nucleotide binding motif. Further affinity purification over ATP-Sepharose isolated PP-1bp80 in a quaternary complex with PP-1C and two other proteins, PP-1bp29 and human p20. Recombinant PP-1bp80 also bound PP-1C and suppressed its activity toward a variety of substrates, suggesting that the protein is a novel regulatory subunit of PP-1. 相似文献