全文获取类型
收费全文 | 2303篇 |
免费 | 107篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 20篇 |
化学工业 | 283篇 |
金属工艺 | 26篇 |
机械仪表 | 18篇 |
建筑科学 | 28篇 |
矿业工程 | 2篇 |
能源动力 | 55篇 |
轻工业 | 231篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 48篇 |
一般工业技术 | 169篇 |
冶金工业 | 1405篇 |
原子能技术 | 8篇 |
自动化技术 | 110篇 |
出版年
2023年 | 9篇 |
2022年 | 17篇 |
2021年 | 34篇 |
2020年 | 21篇 |
2019年 | 36篇 |
2018年 | 46篇 |
2017年 | 42篇 |
2016年 | 52篇 |
2015年 | 30篇 |
2014年 | 39篇 |
2013年 | 78篇 |
2012年 | 46篇 |
2011年 | 54篇 |
2010年 | 55篇 |
2009年 | 56篇 |
2008年 | 63篇 |
2007年 | 50篇 |
2006年 | 44篇 |
2005年 | 31篇 |
2004年 | 30篇 |
2003年 | 30篇 |
2002年 | 21篇 |
2001年 | 30篇 |
2000年 | 23篇 |
1999年 | 50篇 |
1998年 | 449篇 |
1997年 | 261篇 |
1996年 | 163篇 |
1995年 | 104篇 |
1994年 | 75篇 |
1993年 | 97篇 |
1992年 | 25篇 |
1991年 | 27篇 |
1990年 | 15篇 |
1989年 | 26篇 |
1988年 | 13篇 |
1987年 | 24篇 |
1986年 | 19篇 |
1985年 | 17篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 9篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 21篇 |
1976年 | 57篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有2411条查询结果,搜索用时 15 毫秒
1.
Alfredo M. Gravagnuolo Eden Morales‐Narváez Charlene Regina Santos Matos Sara Longobardi Paola Giardina Arben Merkoçi 《Advanced functional materials》2015,25(38):6084-6092
Class I hydrophobin Vmh2, a peculiar surface active and versatile fungal protein, is known to self‐assemble into chemically stable amphiphilic films, to be able to change wettability of surfaces, and to strongly adsorb other proteins. Herein, a fast, highly homogeneous and efficient glass functionalization by spontaneous self‐assembling of Vmh2 at liquid–solid interfaces is achieved (in 2 min). The Vmh2‐coated glass slides are proven to immobilize not only proteins but also nanomaterials such as graphene oxide (GO) and quantum dots (QDs). As models, bovine serum albumin labeled with Alexa 555 fluorophore, anti‐immunoglobulin G antibodies, and cadmium telluride QDs are patterned in a microarray fashion in order to demonstrate functionality, reproducibility, and versatility of the proposed substrate. Additionally, a GO layer is effectively and homogeneously self‐assembled onto the studied functionalized surface. This approach offers a quick and simple alternative to immobilize nanomaterials and proteins, which is appealing for new bioanalytical and nanobioenabled applications. 相似文献
2.
3.
TG Morales 《Canadian Metallurgical Quarterly》1997,15(6):346-356
Although adenocarcinoma of the stomach has decreased in incidence over the past several decades, cancer of the gastric cardia has increased rapidly over this time frame. There are several differences between adenocarcinoma of the cardia and distal stomach with respect to epidemiology, risk factors, and prognosis. In addition, recent data raise questions with regard to possible associations of cardia cancer with Barrett's esophagus, intestinal metaplasia of the cardia, and Helicobacter pylori. This article will review the current literature with regard to this important tumor and explore these potential disease associations. 相似文献
4.
A Abeliovich C Chen Y Goda AJ Silva CF Stevens S Tonegawa 《Canadian Metallurgical Quarterly》1993,75(7):1253-1262
Calcium-phospholipid-dependent protein kinase (PKC) has long been suggested to play an important role in modulating synaptic efficacy. We have created a strain of mice that lacks the gamma subtype of PKC to evaluate the significance of this brain-specific PKC isozyme in synaptic plasticity. Mutant mice are viable, develop normally, and have synaptic transmission that is indistinguishable from wild-type mice. Long-term potentiation (LTP), however, is greatly diminished in mutant animals, while two other forms of synaptic plasticity, long-term depression and paired-pulse facilitation, are normal. Surprisingly, when tetanus to evoke LTP was preceded by a low frequency stimulation, mutant animals displayed apparently normal LTP. We propose that PKC gamma is not part of the molecular machinery that produces LTP but is a key regulatory component. 相似文献
5.
CF Wippermann RG Huth FX Schmidt J Thul M Betancor D Schranz 《Canadian Metallurgical Quarterly》1996,22(5):467-471
OBJECTIVE: To compare a system that continuously monitors cardiac output by the Fick principle with measurements by the thermodilution technique in pediatric patients. DESIGN: Prospective direct comparison of the above two techniques. SETTING: Pediatric intensive care unit of a university hospital. PATIENTS: 25 infants and children, aged 1 week to 17 years (median 10 months), who had undergone open heart surgery were studied. Only patients without an endotracheal tube leak and without a residual shunt were included. METHODS: The system based on the Fick principle uses measurements of oxygen consumption taken by a metabolic monitor and of arterial and mixed venous oxygen saturation taken by pulse- and fiberoptic oximetry to calculate cardiac output every 20s. INTERVENTIONS: In every patient one pair of measurements was taken. Continuous Fick and thermodilution cardiac output measurements were performed simultaneously, with the examiners remaining ignorant of the results of the other method. RESULTS: Cardiac output measurements ranged from 0.21 to 4.55 l/min. A good correlation coefficient was found: r2 = 0.98; P < 0.001; SEE = 0.41 l/min. The bias is absolute values and in percent of average cardiac output was - 0.05 l/min or - 4.4% with a precision of 0.32 l/min or 21.3% at 2 SD, respectively. The difference was most marked in a neonate with low cardiac output. CONCLUSION: Continuous measurement of cardiac output by the Fick principle offers a convenient method for the hemodynamic monitoring of unstable infants and children. 相似文献
6.
7.
8.
9.
10.
The skeletal muscle relaxant dantrolene inhibits the release of Ca2+ from the sarcoplasmic reticulum during excitation-contraction coupling and suppresses the uncontrolled Ca2+ release that underlies the skeletal muscle pharmacogenetic disorder malignant hyperthermia; however, the molecular mechanism by which dantrolene selectively affects skeletal muscle Ca2+ regulation remains to be defined. Here we provide evidence of a high-affinity, monophasic inhibition by dantrolene of ryanodine receptor Ca2+ channel function in isolated sarcoplasmic reticulum vesicles prepared from malignant hyperthermia-susceptible and normal pig skeletal muscle. In media simulating resting myoplasm, dantrolene increased the half-time for 45Ca2+ release from both malignant hyperthermia and normal vesicles approximately 3.5-fold and inhibited sarcoplasmic reticulum vesicle [3H]ryanodine binding (Ki approximately 150 nM for both malignant hyperthermia and normal). Inhibition of vesicle [3H]ryanodine binding by dantrolene was associated with a decrease in the extent of activation by both calmodulin and Ca2+. Dantrolene also inhibited [3H]ryanodine binding to purified skeletal muscle ryanodine receptor protein reconstituted into liposomes. In contrast, cardiac sarcoplasmic reticulum vesicle 45Ca2+ release and [3H]ryanodine binding were unaffected by dantrolene. Together, these results demonstrate selective effects of dantrolene on skeletal muscle ryanodine receptors that are consistent with the actions of dantrolene in vivo and suggest a mechanism of action in which dantrolene may act directly at the skeletal muscle ryanodine receptor complex to limit its activation by calmodulin and Ca2+. The potential implications of these results for understanding how dantrolene and malignant hyperthermia mutations may affect the voltage-dependent activation of Ca2+ release in intact skeletal muscle are discussed. 相似文献