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   106篇
  免费   1篇
化学   44篇
晶体学   3篇
力学   1篇
数学   3篇
物理学   56篇
  2022年   1篇
  2020年   2篇
  2017年   2篇
  2015年   2篇
  2013年   1篇
  2012年   1篇
  2011年   7篇
  2010年   1篇
  2009年   1篇
  2008年   2篇
  2007年   5篇
  2006年   11篇
  2005年   2篇
  2004年   8篇
  2003年   6篇
  2002年   4篇
  2001年   7篇
  2000年   2篇
  1999年   4篇
  1996年   1篇
  1995年   5篇
  1994年   2篇
  1993年   5篇
  1992年   1篇
  1991年   3篇
  1990年   3篇
  1989年   2篇
  1988年   1篇
  1987年   3篇
  1986年   1篇
  1984年   3篇
  1982年   2篇
  1975年   3篇
  1974年   2篇
  1973年   1篇
排序方式: 共有107条查询结果,搜索用时 15 毫秒
91.
We used two-dimensional (2-D) electrophoresis to analyze the protein composition of fluid recovered by bronchoalveolar lavage (BALF) from patients with sarcoidosis and idiopathic pulmonary fibrosis, two forms of interstitial lung disease with different cellular composition and cytokine profile in BALF. They are also characterized by different pathogenesis and clinical evolution, idiopathic pulmonary fibrosis being less favorable than sarcoidosis due to rapidly progressive pulmonary fibrosis. Thirty-eight proteins or protein fragments, never previously assigned in BALF samples, were identified by various methods including mass fingerprinting of tryptic digests. Comparison of the BALF protein maps of the two groups of patients showed 32 spots with statistically significant disease-related variations in relative abundance. In sarcoidosis we found an increase in the amount of several plasma proteins, while in idiopathic pulmonary fibrosis we observed a statistically significant increase in low-molecular-weight proteins, many of which are involved in inflammatory processes (such as MIF and calgranulin) or antioxidant response (such as antioxidant peroxysomal enzyme and thioredoxin peroxidase 2). 2-D electrophoresis allowed us to identify new BALF proteins and to characterize protein composition in patients with sarcoidosis and idiophatic pulmonary fibrosis. Comparison of the gels of the two diseases showed that they differ in BALF protein profiles as they do in type of immune response.  相似文献   
92.
The brownian motion in a quartic double-well potential driven by coloured noise is investigated in the low-viscosity limit by means of analogue simulation. The dependence of the escape rate on the noise correlation-time τ is determined for the conditions simulated: the escape rate decreases exponentially with increasing τ2. The relevant law is derived theoretically in the limit of vanishingly small viscosity and high potential barriers.  相似文献   
93.
Heterojunction diodes fabricated by plasma enhanced chemical vapor deposition of hydrogenated amorphous carbon (a-C:H) and fluorine-doped amorphous carbons (a-C:H:F) on p-type silicon are analyzed in terms of their electronic and photovoltaic properties. Their structural and optical properties were identified by Raman spectroscopy, X-ray photoelectron spectroscopy, ellipsometry, and UV-VIS transmittance. The nature of the heterojunction is confirmed by the rectifying current-voltage characteristic of carbonaceous deposits/p-Si junction. The diodes show a behavior dependent on the amount of the fluorine content. The photovoltaic behavior of the junction is investigated as a function of both fluorine incorporation and thermal treatment of the a-C:H:F films after the deposition. Better photovoltaic effects were observed from annealed a-C:H:F heterojunction structures. The optical and structural characterization performed on films after the thermal treatment indicates that this behavior is most likely due to an extended graphitization.  相似文献   
94.
The equestrian monument of the emperor Marcus Aurelius (II century A.D.) is experimentally examined. The strain fields and the displacements of the statue of the horse, determined by the load of the emperor statue, are recorded. The experimental values point out that the localization of the contact areas can significantly influence the behavior of the monument. By comparing the experimental results with the numerical ones, a satisfactory agreement emerges. Paper was presented at the 1989 SEM Spring Conference on Experimental Mechanics held in Cambridge, MA on May 28–June 1.  相似文献   
95.
we describe a new and efficient synthesis of the title compounds, directly obtained by photochemical alkoxilation or acetoxilation of trans-enedicarbonyl compounds. A possible mechanism is discussed.  相似文献   
96.
α-Diazomethyl ketones derived from carboxylic acids are photolyzed in the presence of imidazole to give the corresponding nor olefins or, in the case of aryl diazo ketones, the corresponding, stable imidazolides. The application of the method to a novel degradation of bile acid side chain is reported.  相似文献   
97.
98.
We address the problem of binary classification by using a quantum version of the Nearest Mean Classifier (NMC). Our proposal is indeed an advanced version of previous one (see Sergioli et al. 2017 that i) is able to be naturally generalized to arbitrary number of features and ii) exhibits better performances with respect to the classical NMC for several datasets. Further, we show that the quantum version of NMC is not invariant under rescaling. This allows us to introduce a free parameter, i.e. the rescaling factor, that could be useful to get a further improvement of the classification performance.  相似文献   
99.
100.
Crack free and smooth surfaces of poly [4,5-difluoro 2,2-bis (trifluoromethyl)-(1,3 dioxole)-co-tetrafluoroethylene] (TFE-co-TFD) thin films have been deposited by wet chemical dip coating technique on polished quartz and glass slide substrates. The deposited films have been subjected to annealing at different temperatures ranging from 100 to 500 °C for 1 h in argon atmosphere. The elemental composition of the as-deposited (xerogel) thin film as well as film annealed at 400 °C was measured by X-ray photoelectron spectroscopy and observed that there was no change in the composition of the film. X-ray diffraction pattern revealed the amorphous behaviour of both as-deposited and film annealed at 400 °C. Surface morphology and elemental composition of the films have been examined by employing scanning electron microscopy attached with energy dispersive X-ray analyser, respectively. It was found that as the annealing temperature increased from 100 to 400 °C, nano-hemisphere-like structures have been grown, which in turn has shown increase in the water contact angle from 122o to 148o and oil (peanut) contact angle from 85° to 96°. No change in the water contact angle (122°) has been observed when the films deposited at room temperature were heated in air from 30 to 80 °C as well as exposed to steam for 8 days for 8 h/day indicating thermal stability of the film.  相似文献   
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