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   2356篇
  免费   7篇
综合类   4篇
化学工业   38篇
金属工艺   1篇
轻工业   6篇
水利工程   1篇
石油天然气   1篇
无线电   2篇
一般工业技术   4篇
冶金工业   2305篇
自动化技术   1篇
  2019年   1篇
  2018年   3篇
  2017年   1篇
  2016年   1篇
  2015年   5篇
  2014年   5篇
  2013年   6篇
  2012年   3篇
  2011年   3篇
  2010年   4篇
  2009年   2篇
  2008年   2篇
  2007年   4篇
  2006年   2篇
  2005年   5篇
  2004年   1篇
  2003年   1篇
  2000年   2篇
  1999年   78篇
  1998年   730篇
  1997年   399篇
  1996年   290篇
  1995年   160篇
  1994年   121篇
  1993年   140篇
  1992年   17篇
  1991年   24篇
  1990年   24篇
  1989年   30篇
  1988年   34篇
  1987年   24篇
  1986年   29篇
  1985年   22篇
  1983年   8篇
  1982年   2篇
  1981年   11篇
  1980年   14篇
  1979年   3篇
  1978年   7篇
  1977年   38篇
  1976年   100篇
  1975年   4篇
  1974年   1篇
  1973年   1篇
  1955年   1篇
排序方式: 共有2363条查询结果,搜索用时 10 毫秒
81.
82.
83.
84.
85.
From January 1981 through October 1995, a total of 28 patients underwent surgery for metastatic lung tumors in our institute. A retrospective review and survival analysis of these patients are reported. There were 12 males and 16 females, with the mean age of 57 years. Of them, 20 patients had solitary lesions. Pulmonary metastasis was from the colon in 8 patients, from the breast in 5, from the stomach and the uterus in each 3, from the bladder, the rectum and the soft tissue in each 2, and from the kidney, the ovarium and the thyroid in each 1. A lobectomy was performed in 22 patients, 17 of whom were accompanied with mediastinal lymph node dissection (R2a). Partial resection without lymph node dissection was performed in 6 patients (R0). Overall 5-year survival was 24.7%. Four-year or over survivor were 4 patients who underwent a lobectomy with R2a. The patients undergoing lobectomy had a significantly better prognosis compared with patients with partial resection (p<0. 05). The patients with R2a had significantly less local recurrence than patients with R1 or R0 (p<0.05). We conclude that lobectomy with R2a is suitable treatment for metastatic lung cancer.  相似文献   
86.
In Bacillus transformation, sexual isolation is known to be an exponential function of the sequence divergence between donor and recipient. Here, we have investigated the mechanism under which sequence divergence results in sexual isolation. We tested the effect of mismatch repair by comparing a wild-type strain and an isogenic mismatch-repair mutant for the relationship between sexual isolation and sequence divergence. Mismatch repair was shown to contribute to sexual isolation but was responsible for only a small fraction of the sexual isolation observed. Another possible mechanism of sexual isolation is that more divergent recipient and donor DNA strands have greater difficulty forming a heteroduplex because a region of perfect identity between donor and recipient is required for initiation of the heteroduplex. A mathematical model showed that this heteroduplex-resistance mechanism yields an exponential relationship between sexual isolation and sequence divergence. Moreover, this model yields an estimate of the size of the region of perfect identity that is comparable to independent estimates for Escherichia coli. For these reasons, and because all other mechanisms of sexual isolation may be ruled out, we conclude that resistance to heteroduplex formation is predominantly responsible for the exponential relationship between sexual isolation and sequence divergence in Bacillus transformation.  相似文献   
87.
The aim of this 1 week study was to compare the biologic effects induced by Betaseron and AVONEX using their approved dose, route, and schedule. Sixteen healthy volunteers were randomly assigned to receive either a single i.m. dose of AVONEX (6 million International Units [MIU]) or, every other day s.c. doses of Betaseron (8 MIU). Common side effects associated with interferon-beta (IFN-beta) treatment and biologic response parameters (neopterin, beta2-microglobulin, interleukin-10 [IL-10], and MxA protein levels in blood) were measured. Ibuprofen was administered to all subjects throughout the study. Fever, chills, and myalgia occurred most frequently and with the greatest severity between 6 and 12 h after the first dose of either IFN-beta. Despite the additional dosing of subjects in the Betaseron group, the incidence, duration, and severity of the side effects were not significantly different from those in the AVONEX group. Biologic response parameters reached similar maximum concentrations in both treatment groups. In the Betaseron group, neopterin and beta2-microglobulin levels remained significantly greater than baseline throughout the 7 day study, whereas those in the AVONEX group were elevated only through day 5. Betaseron treatment significantly increased IL-10 levels above baseline, but AVONEX treatment did not. The overall induction of neopterin, beta2-microglobulin, and IL-10 (as measured by area under the concentration-time curve) was significantly greater in the Betaseron group than the AVONEX group (p = 0.031). The results of this study demonstrate that the approved Betaseron dosing regimen, in combination with ibuprofen use, provided a significantly greater and more consistently elevated biologic response compared with that of AVONEX and did so with a side effects profile comparable to that of once a week AVONEX dosing.  相似文献   
88.
Monoclonal antibodies (MoAbs) raised against Trypanosoma cruzi microsomal fraction (Mc) and cross-reactive with mammalian tissues were used to evaluate the ability of cross-reactive T. cruzi antigens to induce an immune response in Chagas' disease. Thus, we studied the ability of sera from Chagas' disease patients (CDP) with different degrees of cardiac dysfunction to block the immune recognition of these MoAb to the target antigen determining for each serum an inhibition index (II). By means of this approach we inferred that blocking of monoclonal antibody binding to T. cruzi microsomes by subjects' serum represents antibodies with the same reactivity. After serological and medical examinations, individuals were separated into the following groups: Chagas' disease patients without manifest cardiac involvement (CDP-0), CDP with suspected or borderline cardiac disease (CDP-1), CDP with moderate myocardial dysfunction (CDP-2), CDP with overt cardiac dysfunction (CDP-3) and controls including healthy subjects (HS) and patients with idiopathic myocarditis (IMP). The reactivity between MoAb 5F2 and its target antigen was significantly (p < 0.05) inhibited by sera from CDP irrespective of the clinical stage [CDP: n = 46, 50 +/- 20, mean II +/- SD: control: n = 16, 18 +/- 8]. Moreover, 5F2 was able to distinguish (p < 0.05) sera from CDP with mild disease (CDP clinical grade 0/1: n = 26, 34 +/- 18) from that of CDP with severe disease (CDP clinical grade 2/3: n = 20, 67 +/- 7). Moreover, the inhibitory capacity of sera from asymptomatic CDP (CDP-0) correlated with patients age (r = 0.66, p < 0.05). CDP-0 below or equal 40 years of age had results (n = 15, 25 +/- 13) comparable (p > 0.05) to that of controls while mean inhibition of CDP-0 over 40 years of age (n = 5, 60 +/- 5) was indistinguishable (p > 0.05) from that of patients with severe disease. Competitive assay with MoAb 5A9B11 also showed significant differences (p < 0.05) between sera from CDP (n = 46, 46 +/- 24) and controls (n = 13, 5 +/- 5). On the contrary, the differences observed between CDP with different cardiac involvement was not significant (mild: n = 26, 31 +/- 22; severe: n = 20, 66 +/- 11). However a thorough study of data from asymptomatic sera revealed the existence of two levels of reactivity, with low and high capacity to inhibit the reaction of 5A9B11 against Mc. On the contrary, CDP sera showed a blocking activity for 1A10C11 comparable to that of controls (CDP: n = 25, 19 +/- 9; control: n = 12, 14 +/- 6). Some cross-reactive MoAbs recognized epitopes partially composed of carbohydrates. Interestingly, 5F2 and 5A9B11 epitopes did not appear to have carbohydrates moieties. In summary, immunoinhibition assays revealed differences in the immune response of chronic chagasic patients against parasite epitopes. These results have opened the possibility to identify a prognosis marker of the disease suggesting the clinical utility of monitoring levels of these anti-Mc antibodies in patients with chronic Chagas' disease.  相似文献   
89.
90.
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