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151.
152.
Development of a multiresidue method for the determination of multiclass pesticides in soil using GC
Jeong‐Heui Choi A. M. Abd El‐Aty M. E. Assayed Woo Jung Choi Kwang Sik Yoon Seong‐Soo Han Hee Kweon Kim Byung Jun Park Kap Soon Kim Sang Don Kim Hun Geun Choi Jae‐Han Shim 《Biomedical chromatography : BMC》2010,24(8):893-901
The principal objective of the present study was to develop a multiresidue analytical method for 62 pesticides in a soil matrix. Soil samples were fortified with known quantities of pesticides at two different concentration levels (0.1 and 0.01 μg/g) and the analytes were extracted via a liquid–solid extraction method. The pesticides were separated on an HP5 capillary column and were detected by gas chromatography coupled to an electron capture detector (GC‐ECD). The method was validated, considering its good linearities (r2 = 0.978–0.999), specificity and recovery characteristics. Recoveries were found between 70.3 and 113.4% for all pesticides except edifenphos (67.5%) and dichlobenil (69.5%) spiked at a 0.1 μg/mL concentration level and 74.5–117% except ethalfluralin (63.3%) and dichlobenil (51.9%) spiked at a concentration of 0.01 μg/mL. The developed method could be utilized as a simple and cost‐effective method for the routine analysis of 62 pesticides in soil samples. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
153.
The oxygen atom of dimethylformamide (DMF) is a good electron doaor site and in a proton donor solvent the solute-solvent interactions would include hydrogen bonding at this site. As this hydrogen bonding is expected to be relatively strong, it would predominate when both the lMF and the protonic acid are present at very low concentration in a solvent such as carbon tetrachloride, and the effect of this hydrogen bonding on the proton chemical shifts and coupling constants i n LMF can be observed. If the protonic acid is aromatic, such as phenol, and is in excess of the LMF, other form(s) of solut-olvent association would become significant and give rise to aromatic solvent induced shifts (ASIS), which would obscure the effect of hydrogen bonding at the oxygen site of the MF. The ASIS in DMF are well known, and the shifts have been attributed to the diamagnetic ring current effect of the aromatic solvent and specificsolut-olvent association.1 More recently, the ASIS has been interpreted as the result of time-averaged general solvation around the polar site of the solute.2 相似文献
154.
Soon Ok Jeon 《Tetrahedron》2010,66(36):7295-4343
High triplet energy host materials based on novel fused phenylcarbazole core structure and diphenylphosphine oxide were synthesized and the physical properties of the host materials were investigated. A high triplet energy of 2.95 eV was obtained from the fused phenylcarbazole based host materials and the energy levels could be manipulated using the diphenylphosphine oxide group. The fused phenylcarbazole based high triplet energy host materials showed excellent morphological stability at high temperature. 相似文献
155.
Pei‐Cheng Hsu Yu‐Sheng Chen Yeukuang Hwu J. H. Je G. Margaritondo Eng Soon Tok 《Journal of synchrotron radiation》2015,22(6):1524-1527
X‐ray irradiation is shown to trigger the deposition of Cu from solution, at room temperature, on a wide variety of insulating substrates: glass, passivated Si, TiN/Ti/SiO2/Si and photoresists like PMMA and SU‐8. The process is suitable for patterning and the products can be used as seeds for electroplating of thicker overlayers. 相似文献
156.
In this paper we introduce the notion of TN-groupoids in an arbitrary groupoid, and discuss some properties in Bin(X), and obtain several results related with non-negativity of norms. 相似文献
157.
Mohammednoor Altarawneh Phillip V. Smith Eric M. Kennedy Aloysius Soon 《Applied Surface Science》2010,256(15):4764-1040
First-principles density functional theory and a periodic-slab model have been utilized to investigate the adsorption of a 2-chlorophenol molecule on a CuO(1 1 1) surface with a vacant Cu surface site, namely Cu2O(1 1 1)-CuCUS. Several vertical and flat orientations have been studied. All of these molecular configurations interact very weakly with the Cu2O(1 1 1)-CuCUS surface, an observation which also holds for clean copper surfaces and the Cu2O(1 1 0):CuO surface. Hydroxyl-bond dissociation assisted by the surface was found to be endoergic by 0.42-1.72 eV, depending predominantly on the position of the isolated H on the surface. In addition, the corresponding adsorbed 2-chlorophenoxy moiety was found to be more stable than a vacuum 2-chlorophenoxy radical by about 0.76 eV. Despite these predicted endoergicities, however, we would predict the formation of 2-chlorophenoxy radicals from gaseous 2-chlorophenol over the copper (I) oxide Cu2O(1 1 1)-CuCUS surface to be a feasible and important process in the formation of PCDD/Fs in the post-flame region where gas-phase routes are negligible. 相似文献
158.
Yun‐Gon Kim Geun‐Cheol Gil Kyung‐Soon Jang Sukmook Lee Hyoung‐Il Kim Jung‐Sik Kim Junho Chung Chung‐Gyu Park David J. Harvey Byung‐Gee Kim 《Journal of mass spectrometry : JMS》2009,44(7):1087-1104
N‐glycan structures released from miniature pig endothelial and islet cells were determined by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF), negative ion electrospray ionization (ESI) MS/MS and normal‐phase high performance liquid chromatography (NP‐HPLC) combined with exoglycosidase digestion. Totally, the identified structures were 181 N‐glycans including 129 sialylated and 18 α‐galactosylated glycans from pig endothelial cells and 80 N‐glycans including 41 sialylated and one α‐galactosylated glycans from pig islet cells. The quantity of the α‐galactosylated glycans from pig islet cells was certainly neglectable compared to pig endothelial cells. A number of NeuGc‐terminated N‐glycans (80 from pig endothelial cells and 13 from pig islet cells) are newly detected by our mass spectrometric strategies. The detailed structural information will be a matter of great interest in organ or cell xenotransplantation using α 1,3‐galactosyltransferase gene‐knockout (GalT‐KO) pig. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
159.
Kyungtae Kim Sung Chun Cho Anthony Cova Ik Soon Jang Sang Chul Park 《Experimental & molecular medicine》2009,41(5):334-340
The effects of glucagon and epinephrine on gluconeogenesis in young (4 month) and old (24 month) Fisher 344 rat hepatocytes were compared. In contrast to glucagon, which had a similar effect on gluconeogenesis in both young and old cells, epinephrine caused a smaller increase in gluconeogenesis in old rat hepatocytes than in young hepatocytes. β2 adrenergic receptor (β2-AR) expression slightly decreased in aged rat liver, and there were differences between young and old hepatocytes in their patterns of G protein coupled receptor kinases, which are involved in the activation of β2-AR receptor signal desensitization. The major isoform of the kinase changed from GRK2 to GRK3 and the expression of β-arrestin, which is recruited by the phosphorylated β2-AR for internalization and degradation, increased in aged rat liver. GRK3 overexpression also decreased the glucose output from young rat hepatocytes. We conclude that an age-associated reduction in epinephrine-induced gluconeogenesis occurs through the epinephrine receptor desensitizing system. 相似文献
160.
Seo Y Ninh TH Hong SM Kim S Kang TJ Kim H Kim J 《Langmuir : the ACS journal of surfaces and colloids》2006,22(7):3062-3067
We present an investigation of the interfacial reinforcement between a flexible folded-chain polymer (functionalized polypropylene-maleic anhydride-grafted polypropylene, MAPP) and a rodlike polymer (a themotropic liquid crystalline polymer, TCLP - poly(ester amide)). Fracture toughness was measured using an asymmetric double-cantilever beam test (ADCB). High fracture toughness at the bonding temperature of 200 degrees C indicates that a chemical reaction has occurred at the interface to provide a strong interaction between MAPP and TLCP. Despite the higher modulus of TLCP, the fracture was propagated in the TLCP phase because of inherent TLCP domain structure. An analysis on the locus of failure revealed that at constant bonding temperature the fracture toughness between MAPP and TLCP was influenced not only by the bonding temperature but also by the bonding time. The fracture toughness increased with the bonding temperature until 200 degrees C was reached and then decreased at higher bonding temperature. The fracture toughness increased with annealing time until it reached a plateau value. We ascribe the dependence of the fracture toughness on the bonding time to the progressive occurrence of two different failure mechanisms, adhesive failure and cohesive failure. The adhesive strength increased with bonding temperature whereas the cohesive strength decreased because of weaker adhesion between TLCP crystalline domains. The dependence of fracture toughness on bonding time was explained in terms of the TLCP crystalline domain structure. 相似文献