首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   305篇
  免费   5篇
工业技术   310篇
  2020年   2篇
  2019年   5篇
  2018年   7篇
  2017年   4篇
  2016年   6篇
  2015年   2篇
  2014年   4篇
  2013年   11篇
  2012年   8篇
  2011年   11篇
  2010年   5篇
  2009年   6篇
  2008年   5篇
  2007年   15篇
  2006年   7篇
  2005年   9篇
  2004年   8篇
  2003年   3篇
  2002年   5篇
  2001年   6篇
  2000年   5篇
  1999年   10篇
  1998年   27篇
  1997年   22篇
  1996年   10篇
  1995年   15篇
  1994年   8篇
  1993年   10篇
  1992年   5篇
  1991年   4篇
  1990年   9篇
  1989年   6篇
  1988年   8篇
  1986年   3篇
  1985年   3篇
  1984年   2篇
  1983年   4篇
  1981年   4篇
  1977年   2篇
  1976年   3篇
  1975年   1篇
  1974年   1篇
  1972年   1篇
  1971年   1篇
  1970年   1篇
  1968年   2篇
  1967年   2篇
  1966年   2篇
  1965年   2篇
  1963年   1篇
排序方式: 共有310条查询结果,搜索用时 15 毫秒
21.
Bipolar membrane electrodialysis is applied to CO2 recovery from alkaline carbonate solution. CO2 in flue gas is captured by an alkaline hydroxide absorbing solution to form an alkaline carbonate solution. The captured CO2 is recovered from the alkaline carbonate solution via bipolar membrane electrodialysis, and the alkaline solution is regenerated simultaneously. To reduce the power requirement for CO2 recovery, this study considers optimal design and operation. Three membrane arrangements were compared, and the results indicate the membrane arrangement comprising a bipolar membrane and cation exchange membrane is the most energy saving. With further optimization of operation conditions, the minimum power requirement for CO2 recovery was reduced to 2.1 MJ/kg‐CO2 (or 2.1 GJ/t‐CO2). © 2009 American Institute of Chemical Engineers AIChE J, 2009  相似文献   
22.
We isolated cDNA corresponding to open reading frame (ORF) 16 of the 81 kb contig of Arabidopsis thaliana chromosome III [Quigley., Nucleic Acids Res., 24, 4313-4318 (1996)] and expressed alpha-mannosidase activity in tobacco suspension-cultured cells, which revealed that ORF16 encodes alpha-mannosidase. We also suggested that Arabidopsis harbors three genes encoding alpha-mannosidase by homology search against the database.  相似文献   
23.
Aromatic nitroso-compounds such as nitrosobenzene inhibited the respiratory burst of intact neutrophils induced by various stimulants, including phorbol 12-myristate 13-acetate and a chemotactic peptide. The compounds also inhibited NADPH-dependent oxygen consumption by cell-free preparations of neutrophils. This indicates that nitroso-compounds act directly on the NADPH-oxidase system. The inhibitory effects induced by several nitroso-compounds, 2-nitrosotoluene, nitrosobenzene, 4-nitrosophenol, and 1-nitrosopyrrolidine, were examined and their inhibition constants, the concentrations causing 50% reduction of oxygen consumption, were found to be 0.043, 0.173, 0.672, and 32.1 mM, respectively. These values correlated well with the hydrophobicity of the compounds: a more hydrophobic compound was a more potent inhibitor against NADPH oxidase, suggesting that the oxidase has a hydrophobic site(s) for interaction with the inhibitors.  相似文献   
24.
Two component water-soluble random copolypeptides consisting of N-hydroxyethyl L-glutamine and hydrophobic L-amino acids such as L-alanine, L-leucine, L-phenylalanine, or L-valine, were prepared by carrying out aminolysis reactions with 2-amino-1-ethanol (E) on starting copolymers consisting of γ-benzyl L-glutamate (B) and the corresponding hydrophobic L-amino acid. The effects of copolymer composition and sequential distributions, as well as molecular conformations, on the rate of degradation by bromelain in a PECF at pH 7.4 and 37.0°C to simulate in vivo polymer degradation. All the samples were found to be extensively degraded by random chain fracture with bromelain. Further, the degradation data for these samples followed the Michaelis-Menten rate law, being of the first order in papain concentration. The nature of side chains and the molecular conformations are important to the rate of degradation by bromelain.  相似文献   
25.
We established gastric cancer-specific CD8+ T-cell (T(CD8+)) lines derived from different lymphocyte sources in the same patients by repeated stimulation with mitomycin-C-treated autologous tumor cells with low-dose interleukin-2, and we compared recognition patterns among the T(CD8+) derived from solid tumor, lymph node metastasis and ascites in the same patient (n = 3) to determine their similarities and differences for therapeutic purposes. We confirmed that gastric cancer-specific T(CD8+) lines can be isolated, in a MHC class I-restricted manner, from solid tumors, metastatic lymph nodes and malignant ascites. T(CD8+) lines derived from tumor-infiltrating lymphocytes (TIL) in solid tumor recognized autologous tumor cells derived from solid tumor, but not autologous tumor cells derived from ascites or metastatic lymph node, while T(CD8+) lines derived from tumor-associated lymphocytes (TAL) in malignant ascites recognized autologous tumor cells derived from ascites, but not tumor cells from solid tumor or metastatic lymph node. Furthermore, T(CD8+) lines derived from regional lymph node lymphocytes (RLNL) recognized autologous tumor cells derived from metastatic lymph nodes, but not tumor cells derived from ascites. No significant differences were seen in MHC class I expression among the tumors derived from solid tumor, lymph node metastasis or ascites in the same patient. This suggests that there are differences of recognition patterns among the TILs, TALs and RLNLs in the same patient and that it is important to consider the source of lymphocytes, e.g., a combination of TILs, TALs and RLNLs, for adoptive immunotherapy in gastric cancer patients.  相似文献   
26.
A reactor system, which continuously hydrolysed the metal alkoxide in an alcohol solution, was designed using an electromagnetic stirrer and an ageing tube. Several monosized colloidal particles were produced by this reactor system, which had high reproducibility and reliability for long-term production. The relation between powder characteristics and experimental parameters such as reagent concentration, mixing rate, ageing time, temperature, was investigated. These parameters had an effect on the particle size, size distribution, morphology and state of agglomeration. It is possible to control the particle size to between 0.1 and 1.0 μm by varying the experimental conditions. A narrower size distribution of powders was obtained by using an electromagnetic stirrer with greater flow rate. Physical and chemical properties of monosized colloidal particles obtained by this reactor were comparable to those of monosized colloidal particles obtained by the batch process.  相似文献   
27.
28.
TNM classification of esophageal carcinoma was first described in the supplement to the first edition of the TNM classification in 1973. In the second edition, the classification was changed based on the data of 1,000 cases from the Task Force on Esophagus of American Joint Committee. In this edition, only the clinical classification was described, but the third edition included both clinical and post-surgical histopathological classification. But the criteria for T and pT classification differed. Before the fourth edition, specialists from Japan and the United States met in Hawaii in 1984. Data of the Japanese Nationwide Registration, including 7,742 patients from 1969 to 1978, were presented. After discussion based on these data, T was classified according to the depth of invasion, and perigastric lymph nodes were included in Regional Nodes in the fourth edition. Then, the TNM Research Committee of ISDE collected patient data of esophageal carcinoma from seven countries, and they were studied according to many factors. Based on these data, two proposals were made to the UICC TNM Committee. First, T1 should be divided into two categories: T1a, Tumor invasion of lamina propria; and T1b, Tumor invasion of submucosa. Second, metastases to distant lymph nodes should be grouped into the N classification instead of M classification. The first was accepted in the TNM Supplement of 1993, and the second will be accepted in the Fifth Edition, which will appear in 1997. It is important to accumulate data on many patients using the uniform registration form and to follow these patients very closely in the discussion of revisions to the TNM classification.  相似文献   
29.
Thanks to the spread of the Internet, opportunities to use online bookstores have been increasing in recent years. However, it is difficult for the typical customer to intuitively grasp which book sells well or which book is recommended by the shop. We have therefore developed a display system for virtual bookstores in which an image of books arranged in a bookshelf or stacked on a table is reproduced by using WebGL. Since the amount of book stock that is managed by the server side needs to be changed as orders come in from clients, we introduce a server side technology using a hypertext preprocessor(PHP).  相似文献   
30.
This report examines the reliability of nighttime blood pressure dipping. Twenty-one individuals were studied twice with ambulatory blood pressure monitoring. On one occasion they were studied as outpatients, and on the other as inpatients on a clinical research ward. Blood pressure monitoring revealed the expected dip in blood pressure at nighttime. However, there was little test-retest reliability across the two settings. The test-retest correlations for the dip in blood pressure across the two settings were nonsignificant for systolic, diastolic, and mean arterial blood pressure. Caution is advised before diagnosing dipping or nondipping on the basis of one 24-h ambulatory blood pressure recording.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号