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21.
我国活性氧化镁生产工艺研究进展 总被引:1,自引:0,他引:1
活性氧化镁是一种高附加值的化工原料,广泛应用于各种化工生产中。重点归纳总结了我国活性氧化镁的生产工艺,内容主要包括固体矿石法和液态镁卤水法,并指出了未来的主要研究方向。 相似文献
22.
Verenice Merlín-Lucas Rosa María Ordoez-Razo Fernando Calzada Aida Solís Normand García-Hernndez Elizabeth Barbosa Miguel Valds 《Molecules (Basel, Switzerland)》2021,26(24)
Annona muricata (Am) is a plant used in traditional Mexican medicine to treat cancer. In this study, ethanol extracts of Am collected in Acapulco and Tecpan from Guerrero state were evaluated orally on Balb/c mice inoculated with 4T1 cells, for cytotoxic activity (CA) on 4T1 cells, in brine shrimp lethality assay (BSLA), and for acute oral toxicity in mice. In addition, ethanol extracts were subjected to high-performance liquid chromatography (HPLC) with diode array detection. Results showed that the extracts collected in December in Acapulco (AcDe) and Tecpan (TeDe) exhibited the most significant antitumor and cytotoxic activity. In the BSLA, the most important effect was observed in the extracts from Acapulco and Tecpan collected in June (AcJu) and August (TeAg), respectively. The samples from Acapulco (AcJu, and AcAg) and Tecpan (TeJu and TeAg) showed the highest toxicity. The analysis of the extracts, AcDe and TeDe, by HPLC revealed that flavonoids, rutin, narcissin, and nicotinflorin were the major components. These findings suggest that extracts from Am collected in Acapulco and Tecpan in the month of December may be an important source to obtain flavonoid glycosides with anticancer potential specifically against breast cancer. This also supports the use of Am to treat cancer in Mexican traditional medicine. 相似文献
23.
24.
25.
砷污染物是水体环境中重点优先监测的污染物之一。归纳总结了近年来高矿化度水体系中痕量砷的测定方法研究进展,内容包括样品的处理(稀释、预富集和基体分离)分析,指出了高矿化度水体系中不同形态砷分析的发展方向。 相似文献
26.
本文用高精度数字式振荡管密度计测定了288K至318K温度范围内Li2SO4 + Na2SO4 + H2O和 Li2SO4 + K2SO4 + H2O三元体系的密度。混合溶液的离子强度范围从0.1到4.5 mol.kg–1,混合溶液中Na2SO4和K2SO4的离子强度分数为0.2,0.4,0.6和0.8。用密度实验值拟合得到了不同温度下Pitzer离子相互作用模型混合参数θV和 ψV,模型的计算值与实验值的偏差在±0.002 g.cm–3以内。用Pitzer模型计算了不同离子强度下三元体系的混合体积。 相似文献
27.
A new phenomenological mathematical model of the propagation of high- and low-salinity solutions through inhomogeneous aquifers is proposed. The model consists of interrelated equations of two-phase flow and diffusive mass transfer through a porous medium in a region with a traveling boundary. Features of different contamination scenarios of are analyzed with reference to particular examples. 相似文献
28.
Saltwater, or brine, underlies freshwater in many aquifers, with a transition zone separating them. Pumping freshwater by a well located above the transition zone produces upconing of the latter, eventually salinizing the pumped water, forcing shut-off. Following the well’s shut-off, the upconed saltwater mound undergoes decay, tending to return to the pre-pumping regime. The FEAS code is used for the simulation of coupled density-dependent flow and salt transport involved in the upconing–decay process. In this code, the flow equation is solved by the Galerkin finite element method (FEM), while the advective–dispersive salt transport equation is solved in the Eulerian–Lagrangian framework. The code does not suffer from the instability constraint on the Peclet number. The code is used to investigate the transient upconing–decay process in an axially symmetric system and to discover how the process is affected by two major factors: the density difference factor (DDF) and the dispersivities. Simulation results show that under certain conditions, pumping essentially freshwater can be maintained for a certain time period, the length of which depends on the dispersivity values used. A recirculating flow cell may occur in the saltwater layer beneath the pumping well, widening the saltwater mound. The decay process is lengthy; it takes a long time for the upconed saltwater to migrate back to its original shape of a horizontal transition zone prior to pumping. However, the wider transition zone caused by hydrodynamic dispersion can never return to the initial one. This indicates that once a pumping well is abandoned because of high salinity, it can be reused for groundwater utilization only after a long time. It is also shown that the upconing–decay process is very sensitive to DDF, which, in our work, ranges from 0 (for an ideal tracer) to 0.2 (for brine). For a DDF of 0.025 (for seawater), local upconing occurs only for low iso-salinity surfaces, while those of high salt concentration remain stable after a short time. For an ideal tracer, all iso-salinity surfaces rise toward the pumping well, whereas for brine only iso-salinity surfaces of very low salinity upcone towards the pumping well. This may imply that the traditional finding that the sharp interface approximation is practically close to the 0.5 iso-salinity surface may not be true for a high DDF solution. 相似文献
29.
Bin Xu Zhenghua Wang Dandan Gao Yaping Dong Wu Li 《International journal of environmental analytical chemistry》2013,93(3):291-301
The ICP-AES technique and experimental design were employed to precisely determine the content of strontium in high Ca/Sr ratio oil field brine of Qaidam basin (Qinghai province, western China). From the statistical analysis using six factor factorial, it was found that Ca2+ is the significant interfering element for the recovery of strontium. Accurate strontium content was derived by eliminating the interference contribution according to the influencing model. The experimental results indicate that, under optimal conditions, the ICP-AES method for strontium determination has low LOD and LOQ, and the precision and accuracy are good with the relatively standard deviation below 1% and recovery between 98.0%?~?105.0%. 相似文献
30.
Roger Young 《Transport in Porous Media》1993,11(2):179-185
Two-phase mixtures of hot brine and steam are important in geothermal reservoirs under exploitation. In a simple model, the flows are described by a parabolic equation for the pressure with a derivative coupling to a pair of wave equations for saturation and salt concentration. We show that the wave speed matrix for the hyperbolic part of the coupled system is formally identical to the corresponding matrix in the polymer flood model for oil recovery. For the class ofstrongly diffusive hot brine models, the identification is more than formal, so that the wave phenomena predicted for the polymer flood model will also be observed in geothermal reservoirs.Roman Symbols
A,B
coefficient matrices (5)
-
c(x,t)
salt concentration (primary dependent variable)
-
C(p, s, c,
q
t)
wave speed matrix (6)
-
f
source term (5)
-
g
acceleration due to gravity (constant)
-
h
b(p, c)
brine specific enthalpy
-
h
v(p)
vapour specific enthalpy
-
j
conservation flux (1)
-
k
absolute permeability (constant)
-
k
b(s), kv(s)
relative permeabilities of the brine and vapour phases
-
K
conductivity
-
p(x,t)
pressure (primary dependent variable)
-
q
volume flux (Darcy velocity) (3)
-
s(x,t)
brine saturation (primary dependent variable)
-
t
time (primary independent variable)
-
T=T
sat(p)
saturation temperature
-
u
b(p, c)
brine specific internal energy
-
u
m T
rock matrix specific internal energy
-
u
v(p)
vapour specific internal energy
-
U(x, t)
shock velocity
-
x
space (primary independent variable)
Greek Symbols
porosity (constant)
-
b(p, c)
brine dynamic viscosity
-
v(p)
vapour dynamic viscosity
-
(p, s, c)
conservation density (1)
-
b(p, c)
brine density
-
v(p)
vapour density
Suffixes
b
brine
-
m
rock matrix
-
t
total
-
v
vapour
-
S
salt
-
M
mass
-
E
energy 相似文献