首页 | 本学科首页   官方微博 | 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   1113篇
  免费   1篇
电工技术   7篇
化学工业   68篇
金属工艺   42篇
机械仪表   53篇
建筑科学   7篇
矿业工程   27篇
能源动力   2篇
轻工业   3篇
水利工程   5篇
石油天然气   32篇
无线电   56篇
一般工业技术   126篇
冶金工业   619篇
原子能技术   36篇
自动化技术   31篇
  2022年   6篇
  2021年   7篇
  2020年   5篇
  2019年   13篇
  2018年   15篇
  2017年   11篇
  2016年   15篇
  2015年   10篇
  2014年   8篇
  2013年   32篇
  2012年   22篇
  2011年   20篇
  2010年   19篇
  2009年   26篇
  2008年   21篇
  2007年   19篇
  2006年   18篇
  2005年   10篇
  2004年   12篇
  2003年   10篇
  2002年   6篇
  2001年   7篇
  2000年   11篇
  1999年   12篇
  1998年   155篇
  1997年   101篇
  1996年   59篇
  1995年   49篇
  1994年   34篇
  1993年   46篇
  1992年   8篇
  1991年   13篇
  1990年   10篇
  1989年   15篇
  1988年   14篇
  1987年   11篇
  1986年   17篇
  1985年   17篇
  1984年   5篇
  1982年   10篇
  1981年   11篇
  1980年   10篇
  1979年   6篇
  1978年   21篇
  1977年   29篇
  1976年   72篇
  1975年   11篇
  1974年   8篇
  1973年   10篇
  1972年   5篇
排序方式: 共有1114条查询结果,搜索用时 15 毫秒
91.
A total of 29 patients with stage IV colorectal cancer were entered into a phase II trial of bolus interleukin-2 (IL-2) and interferon-alpha (IFN alpha) (3 x 10(6) U/m2 of each cytokine given i.v. q8h x 15 doses and repeated in 2 weeks). Immunologic parameters measured on isolated peripheral blood lymphocytes revealed increased activated T cells with upregulated natural killer and lymphokine-activated killer activity. Among 24 evaluable patients, there were 4 partial responses (17%) of short duration ( < or = 6 months). Three of the responding patients had been refractory to prior chemotherapy. Overall median survival in the 24 evaluable patients was 18.5 months. Therapy necessitated an inpatient setting, with the most common toxicities being hypotension, hepatic insufficiency, fever, hypocalcemia, nausea/vomiting, and renal insufficiency. There were two treatment-related deaths. Because neither IL-2 nor IFN alpha alone has significant activity against colorectal cancer, the responses observed in this study suggest a potential synergistic effect between the two cytokines. However, the toxicity and short duration of response without survival benefit do not support the routine use of this regimen as a therapeutic modality for this tumor histology.  相似文献   
92.
93.
94.
95.
Chronic action of different xenobiotics which form a part of condensed hydrogen sulphide-containing gas causes substantial changes in the activity of xenobiotic metabolic enzymes, which is suggestive of the damaged hepatic microsomal monooxygenase system. As the rate of biotransformation becomes higher, there are increases in the activity of microsomal monooxygenases and in the generation of active oxygen forms and hydrogen peroxide, by impairing antiradical and antiperoxide mechanisms. The experimentally used concentration of substances as constituents of condensed gas corresponds to the maximum acceptable air concentration of in the working area of gas-refining plants, but the functional features of the body's detoxifying system--the hepatic monooxygenase system should be taken into account while developing preventive measures of occupational diseases.  相似文献   
96.
Juvenile hormone esterase (JHE; EC 3.1.1.1), which is intrinsically involved in regulation of development of some insect larvae, is rapidly removed from the hemolymph by the pericardial cells. Lys-29 and Lys-524, which are implicated in the degradation of JHE, were mutated to Arg. Neither the half-life of the modified JHE in the hemolymph nor the catalytic parameters were changed significantly, but when combined, these mutations resulted in apparent failure of lysosomal targeting in the pericardial cell complex. A hypothesis for the mechanism of reduced efficiency of lysosomal targeting is presented. Infection of larvae with a recombinant baculovirus expressing the modified JHE resulted in a 50% reduction in feeding damage compared with larvae infected with the wild-type virus, thus demonstrating improved properties as a biological insecticide. These data demonstrate that alteration of specific residues of JHE that disrupted lysosomal targeting, dramatically increased the insecticidal activity of this protein.  相似文献   
97.
Cyclins are essential proteins in cell cycle control, and their deranged expression has been reported to be associated with malignant transformation. Involvement of cyclins in the development of endometrioid carcinomas of the endometrium was studied immunohistochemically using antibodies against both cyclin A and tumor suppressor gene product p53, and their expression was compared with that of Ki-67 antigen. Sixty-two cases of endometrial endometrioid carcinoma and 20 cases of normal endometrium (10 proliferative and 10 secretory phase) were examined. Of the 62 endometrioid carcinomas, atrophic endometrium and hyperplasia were found adjacent to the cancers in 30 and 19 cases respectively. Cyclin A was expressed in < 1% of the glandular cells of normal endometrium in the proliferative phase and in hyperplasia, but was negligible in normal secretory phase and atrophic endometrium. p53 was almost always negative in normal endometrium and hyperplasia. Of the 62 endometrioid carcinomas, 12 tumors (19.4%) overexpressed cyclin A and 21 tumors (33.8%) overexpressed p53 (positive cells > 1%). Cyclin A and p53 were more frequently expressed in poorly differentiated tumors than in well differentiated tumors (cyclin A, p = 0.002; p53, p = 0.016). In addition, cyclin A-positive cells were topographically related to those cells positive for p53 as well as Ki-67. In conclusion, the abnormal expression of cyclin A and p53 is associated with high-grade endometrial endometrioid carcinomas.  相似文献   
98.
99.
Translated from Steklo i Keramika, No. 11, pp. 10–12, November, 1989.  相似文献   
100.
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