全文获取类型
收费全文 | 2404篇 |
免费 | 5篇 |
学科分类
工业技术 | 2409篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 11篇 |
2013年 | 23篇 |
2012年 | 16篇 |
2011年 | 20篇 |
2010年 | 7篇 |
2009年 | 11篇 |
2008年 | 8篇 |
2007年 | 14篇 |
2006年 | 15篇 |
2005年 | 18篇 |
2004年 | 9篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 88篇 |
1998年 | 689篇 |
1997年 | 370篇 |
1996年 | 244篇 |
1995年 | 153篇 |
1994年 | 122篇 |
1993年 | 113篇 |
1992年 | 16篇 |
1991年 | 19篇 |
1990年 | 15篇 |
1989年 | 27篇 |
1988年 | 25篇 |
1987年 | 28篇 |
1986年 | 21篇 |
1985年 | 25篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 18篇 |
1980年 | 14篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 62篇 |
1976年 | 96篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 2篇 |
排序方式: 共有2409条查询结果,搜索用时 15 毫秒
111.
112.
113.
VH Karsdorp GA Dekker A Bast GJ van Kamp AA Bouman JM van Vugt HP van Geijn 《Canadian Metallurgical Quarterly》1998,80(1):39-44
The topoisomerase II alpha (topo II alpha) enzyme is the target for several chemotherapeutic agents, including etoposide, teniposide, mitoxantrone, and doxorubicin (topo II poisons). The enzyme also is a marker of cell proliferation. Most cases of Hodgkin's disease (HD) are responsive to combination chemotherapy regimes that include topo II poisons such as doxorubicin. Immunoperoxidase methods for detection of the topo II alpha isoenzyme are now available for use in formalin-fixed, paraffin-embedded tissues, which may provide information about the proliferative capacity and possible sensitivity of tumors to drugs that target topo II. We used a specific antibody to analyze subsets of HD for topo II alpha staining patterns. Formalin-fixed blocks from 49 cases of HD, including 20 nodular sclerosis (NS), 14 mixed-cellularity (MC), and 15 lymphocyte-predominant (LP) subtypes, were analyzed by dual staining for topo II in combination with monoclonal antibodies against Reed-Sternberg (RS) cells consisting of CD15 for the NS and MC subtypes and CD20 for LP lymphocytic and histiocytic (L & H) cells. The number of morphologically appropriate cells coexpressing the RS or L & H marker and topo II alpha was quantitated. Positive nuclear staining for topo II alpha in RS or L & H cells was seen in 100% of cases, irrespective of subtype. Coexpression of CD15 and topo II alpha was seen in 58.4% of the RS cells or mononuclear variants in NSHD cases and 68.4% in MCHD cases. No significant difference in the percentage of neoplastic cells expressing topo II alpha was found between NS and MC subtypes. Cases of LPHD showed coexpression of CD20 and topo II alpha in 84.4% of the L & H cells, a significant increase over the level of tumor cell coexpression seen in NSHD and MCHD (P < .001). Only one case was found to have a low (< 25% of tumor cell coexpression) level of topo II alpha expression. Immunohistochemical detection of a high level of topo II alpha expression in HD, irrespective of subtype, suggests a molecular explanation for the excellent response of most HD to standard combination chemotherapy, which can include topo II poisons. The LP subtype has a higher expression of topo II alpha in the neoplastic cell population than do NS or MC subtypes, perhaps indicating increased sensitivity of these tumors to topo II poisons. It may be possible to identify subsets of HD that are more or less sensitive to conventional chemotherapeutic regimes, which would help in the selection of appropriate treatment. 相似文献
114.
115.
116.
EJ Reddick 《Canadian Metallurgical Quarterly》1978,49(10):1229-1230
Rapid movement of a patient with decompression sickness sometimes poses problems when the site of the hyperbaric treatment facility is located a considerable distance away. Six cases of aviator decompression sickness were diagnosed in altitude chamber participants during an 18-month period. Five cases were uncomplicated decompression sickness and the sixth case was of central nervous system decompression sickness. All cases were transferred by low-level helicopter flight. No complications were noted when the helicopter stayed within 200 ft (61 m) AGL of the take-off point. Symptoms of decompression sickness did worsen however, when this altitude was exceeded. This study shows that movement of patients with decompression sickness by low-level helicopter flight is both safe and effective, especially when pressurized aircraft is neither available nor practical. 相似文献
117.
A system is described which enables crosswords to be automatically compiled or solved, or which alternatively may assist in their manual compilation or solution. Illustrative examples are quoted and the performance of the system, which has been written for an Acorn BBC model B microcomputer with disc pack and printer, is discussed. 相似文献
118.
H Biran JL Moake RC Reed JU Gutterman EM Hersh EJ Freireich GM Mavligit 《Canadian Metallurgical Quarterly》1976,34(5):493-499
Serum complement levels were assayed in 26 patients with disseminated cancer, who received immunotherapy with infusion of C. parvum. Complement activation, indicated by the consumption of C3 or C4 or both, was found in 46% of the patients. Serum samples showed direct correlation between decreased C3 and conversion of C3 proactivator, whereas such conversion did not occur when C4 alone was decreased. It is concluded that the bypass (properdin) pathway was activated in patients in whom C3 consumption was detected, while the classical (C1) pathway was activated in the patients with C4 consumption unaccompanied by C3 decrease. Direct correlation was observed between delayed cutaneous hypersensitivity reactions to recall antigens and the incidence of C. parvum-associated complement activation. 相似文献
119.
J.?Kiiham?kiEmail author J.?Dekker P.?Pekko H.?Kattelus T.?Sillanp?? T.?Mattila 《Microsystem Technologies》2004,10(5):346-350
This paper reports a novel process sequence for fabricating micromechanical devices on silicon-on-insulator (SOI) wafers. Among the merits of the described process are its improved immunity to stiction and elimination of conductor metal endurance problems during sacrificial etching in hydrofluoric acid. With this novel process one can controllably embed vacuum cavities within SOI substrates. Further processing of such cavity wafers enables realization of a wide variety of micromechanical devices based on single crystalline silicon or even integrated read-out circuitry.K. Järvi and T. Häkkinen are gratefully acknowledged for the device fabrication. The Finnish National Technology Agency, Okmetic, VTI Technologies, and Micro Analog Systems participated in funding this work. The ultrasonic devices were fabricated in collaboration with Autotank, Oras, Suunto, Vaisala, and Enermet. 相似文献
120.
Human factors and folk models 总被引:2,自引:2,他引:0
This paper presents a discussion of the susceptibility of human factors to the use of folk models. The case of automation-induced complacency is used as a guiding example to illustrate how folk models (1) substitute one label for another rather than decomposing a large construct into more measurable specifics; (2) are immune to falsification and so resist the most important scientific quality check; and (3) easily get overgeneralised to situations they were never meant to speak about. We then discuss the link between models and measurements, where the model constrains what can be measured by describing what is essential performance, and where the models parameters become the basis for specifying the measurements. We propose that one way forward for human factors is to de-emphasize the focus on inferred and uncertain states of the mind, and shift to characteristics of human performance instead. 相似文献