全文获取类型
收费全文 | 2053篇 |
免费 | 2篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 28篇 |
金属工艺 | 1篇 |
机械仪表 | 3篇 |
建筑科学 | 1篇 |
轻工业 | 15篇 |
无线电 | 10篇 |
一般工业技术 | 28篇 |
冶金工业 | 1936篇 |
自动化技术 | 31篇 |
出版年
2022年 | 2篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 5篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 51篇 |
1998年 | 564篇 |
1997年 | 285篇 |
1996年 | 218篇 |
1995年 | 116篇 |
1994年 | 100篇 |
1993年 | 109篇 |
1992年 | 26篇 |
1991年 | 31篇 |
1990年 | 27篇 |
1989年 | 42篇 |
1988年 | 44篇 |
1987年 | 36篇 |
1986年 | 35篇 |
1985年 | 20篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 9篇 |
1981年 | 15篇 |
1980年 | 23篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 60篇 |
1976年 | 132篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1966年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有2055条查询结果,搜索用时 0 毫秒
991.
992.
T Tsai S Davalath C Rankin JP Radich D Head FR Appelbaum DH Boldt 《Canadian Metallurgical Quarterly》1996,10(12):1901-1910
To examine the impact of inactivation of tumor suppressor genes on outcome in adult ALL, we compared two groups of patients registered to SWOG treatment protocols for loss of the Rb gene product and p53 overexpression: (1) 89 patients with de novo ALL, and (2) 26 patients with relapsed/refractory ALL. The groups were comparable with respect to age, sex, and race. Cell lysates (> or = 80% blasts) were analyzed by immunoblotting which enabled detection of Rb or p53 proteins in as little as 1 microg of lysate. Loss of Rb expression (pRbneg) was found in 54/85 (64%) de novo and 11/19 (58%) relapsed patients (P = 0.79). Overexpression of p53 (p53abn), indicative of p53 point mutations, was found in 16/75 (21%) de novo and 8/19 (42%) relapsed patients (P = 0.08). Using a nonisotopic RNase cleavage assay, p53 point mutations in exons 5-9 were confirmed in 14/23 (61%) p53abn specimens. For the de novo ALL group, patients with normal Rb protein had higher WBC and higher peripheral blast and lymphocyte counts. Otherwise neither abnormal Rb or p53 expression correlated with any of a large panel of clinical and laboratory variables including FAB class, blast lineage, expression of myeloid antigens or CD34, and presence of the Ph1 chromosome or BCR-ABL. Analyses of treatment outcomes demonstrated no significant impact of Rb or p53 status alone on CR rates, relapse-free or overall survival. An identical percentage (11%) of both de novo and relapsed/refractory patients had concurrent abnormalities of both Rb and p53 expression (pRbneg/p53abn). The survival curve of these patients suggests an increased rate of early death, but the number of patients in this group was small. Summarizing, (1) loss of Rb expression is common in adult ALL; (2) overexpression of p53 may be more frequent in relapsed/refractory than de novo adult ALL; and (3) although Rb or p53 alterations alone are not strong independent predictors of outcome, their concurrent expression may predict a poor response to therapy. 相似文献
993.
One hundred patients with cerebral infarction were observed, the results showed that Ganyang Huafeng Syndrome (GYHFS) was the major syndrome of acute cerebral infarction which was accounted for 60% and Qiyin Liangxu Syndrome (QYLXS), Qixu Xueyu Syndrome (QXXYS) were mainly observed at convalescent stage of this disease which was accounted for 37.78% and 31.11% respectively. This study chose plasma norepinephrine (NE), epinephrne (E), thromboxane B2(TXB2), 6-keto-PGF1 alpha, cortisol (F) and serum triiodothyroidoglobulin (T3) as the monitoring parameters, and the results showed that the increase of plasma NE,F,TXB2, the decrease of serum T3 could be considered as the comprehensive experimental parameters for diagnosing GYHFS of cerebral infarction. 相似文献
994.
PL Carmichael A Hewer J Jacob G Grimmer DH Phillips 《Canadian Metallurgical Quarterly》1993,(124):321-326
Cigarette smoke condensates (CSCs) of both mainstream (MS) and sidestream (SS) smoke were used to treat mice topically in equivalent amounts. Human skin maintained in short-term culture was also treated with the condensates. DNA adducts, induced by the CSCs and detected by the nuclease P1 method of 32P-postlabelling, were quantified in a number of murine tissues and in the human skin DNA. In the five mouse tissues studied both MS-CSC and SS-CSC produced characteristic diagonal radioactive zones on TLC, indicative of the formation of multiple DNA adducts. In three tissues (skin, lung and kidney), SS-CSC induced greater total adduct levels than MS-CSC (statistically significant in skin and kidney, p < 0.05). However, greater adduct levels induced by MS-CSC were recorded for heart and bladder DNA (not statistically significant). Similar results to those found in mouse skin were obtained with human skin; SS-CSC induced a approximately 2-fold greater level of DNA adducts than MS-CSC (p < 0.05). Incubation of DNA directly with condensates in vitro demonstrated that DNA adducts could be formed without an exogenous metabolizing system. This direct interaction of condensates with DNA occurred at similar levels for both MS- and SS-CSC, although inclusion of an oxygen radical-generating system enhanced the SS-CSC binding to a greater extent than that of the MS-CSC. 相似文献
995.
Gait abnormalities in children with cerebral palsy are the consequence of contractures across joints, muscle spasticity, and phasically inappropriate muscle action. Though abnormalities involving one of the major joints of the lower extremity will usually have consequences on the function of the other joints, it is possible to recognize certain primary disorders at each joint. The most common gait abnormalities of the knee in patients with cerebral palsy occur in the sagittal plane. Based on the experience gained from performing gait analysis on more than 588 patients with cerebral palsy, four primary gait abnormalities of the knee have been identified: jump knee, crouch knee, stiff knee, and recurvatum knee. In this review, each abnormality is described by its motion analysis laboratory profile (physical examination, motion parameters, electromyography [EMG] data, and force plate data). The most common etiologies and the consequences for gait of each disorder are also considered. Appreciation of the most common pathologic patterns of gait should facilitate accurate and detailed analysis of the individual patient with gait abnormalities. 相似文献
996.
PURPOSE: To determine whether lacrimal gland acinar cells are involved in modulating local immune response; to isolate and characterize a lacrimal gland factor that exerts biological activities on T lymphocytes. METHODS: A protein factor has been purified from lacrimal gland extracts by a combination of ion exchange and gel-filtration chromatography. This factor has the capacity to enhance proliferation of T lymphocytes upon stimulation with a mitogen or an antigen. We have, therefore, called this substance lacrimal gland-derived lymphocyte proliferation potentiating factor (LG-F). RESULTS: Lacrimal gland-derived lymphocyte proliferation potentiating factor has a molecular weight of approximately 65,000 daltons as determined by gel-filtration and by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. T cells demonstrate greater proliferation when cultured with high concentrations of concanavalin A (Con A) in the presence of LG-F, as compared with culture without addition of LG-F. This enhancing effect of LG-F may be mediated by IL-2, because the final cell count correlates with the levels of IL-2 secreted by LG-F-activated cells. Lacrimal gland-derived lymphocyte proliferation potentiating factor is nonmitogenic for T cells, but its potentiating effect is antigen-dependent. Dual stimulation of OA-primed T cells with both OA and LG-F results in greater proliferative activity, in contrast to culture with OA alone. CONCLUSIONS: The results suggest that lacrimal gland cells may interact with the immune system by elaborating nonspecific factors that modulate lymphocyte proliferation and augment lymphokine production. The presence of such a factor in the lacrimal gland may prove to be of importance in the generation of local immune responses. 相似文献
997.
998.
999.
Nitin Jadhav Jacob Wasserman Fei Pei Eric Chason 《Journal of Electronic Materials》2012,41(3):588-595
Stress is believed to provide the driving force for growth of Sn whiskers, so stress relaxation in the Sn layer plays a key
role in their formation. To understand and enhance stress relaxation in Sn-based films, the effects of Pb alloying and microstructure
on their mechanical properties have been studied by observing the relaxation of thermal expansion-induced strain. The relaxation
rate is found to increase with film thickness and grain size in pure Sn films, and it depends on the microstructure in Pb-alloyed
Sn films. Measurements of multilayered structures (Sn on Pb-Sn and Pb-Sn on Sn) show that changing the surface layer alone
is not sufficient to enhance the relaxation, indicating that the Pb enhances relaxation in the bulk of the film and not by
surface modification. Implications of our results for whisker mitigation strategies are discussed. 相似文献
1000.