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101.
102.
Dr. Zhipeng Zhang Dr. Maxim Ratnikov Dr. Glen Spraggon Dr. Phil B. Alper 《Angewandte Chemie (International ed. in English)》2018,57(4):904-908
The photoinduced rearrangement pathways of simple 2,5‐dienones and the natural product santonin were found to be effectively rerouted by amines, giving rise to unprecedented products. Either cis olefins or cyclobutenes were obtained from 4,4‐disubstituted 2,5‐dienone upon irradiation (365 nm) in the presence of various amines depending on the solvent. Previously undescribed [4.4.0] and [5.3.0] fused‐ring‐containing products were obtained when santonin was irradiated (365 nm) in the presence of methylamine. The amines present in these reactions were incorporated into the products by means of amide‐group formation. 相似文献
103.
Phil Hanlon 《Journal of Algebra》1997,190(2):435
LetPbe a rooted tree with rootrand vertex set {1, 2,…,n}. ConsiderPto be a poset by sayingu ≤ vifuis on the path fromrtov. LetZ[P] be the span of all matriceszuvsuch thatu <P v, wherezuvis then × nmatrix with a 1 in theu, ventry and 0's elsewhere. Note thatZ[P] is a nilpotent Lie subalgebra of ?n(). I. Hozo (Electron. J. Combin., to appear) studied the Laplacian of the Koszul complex for computing the Lie algebra homology ofZ[P]. He showed that the tree structure ofPforces significant simplifications in the Laplacian. He went on to conjecture that the eigenvalues of the Laplacian are indexed by certain labellings ofPby partitions. He gave a simple method for determining the eigenvalue indexed by a labelling. In this paper we prove Hozo's conjecture. As a consequence, we deduce that all eigenvalues of the Laplacian are integers. 相似文献
104.
Phil Hanlon 《Inventiones Mathematicae》1986,86(1):131-159
Summary LetA+(k) denote the ring [t]/t
k+1
and letG be a reductive complex Lie algebra with exponentsm
1, ...,m n. This paper concerns the Lie algebra cohomology ofGA
+(k) considered as a bigraded algebra (here one of the gradings is homological degree and the other, which we callweight, is inherited from the obvious grading ofGA
+(k)). We conjecture that this Lie algebra cohomology is an exterior algebra withk+1 generators of homological degree 2m
s
+1 fors=1,2, ...,n. Of thesek+1 generators of degree 2m
s
+1, one has weight 0 and the others have weights (k+1)m
s
+t fort=1,2, ...,k.It is shown that this conjecture about the Lie algebra cohomology of A
+(k) implies the Macdonald root system conjectures. Next we consider the case thatG is a classical Lie algebra with root systemA
n
,B
n
,C
n
, orD
n. It is shown that our conjecture holds in the limit onn asn approaches infinity which amounts to the computation of the cyclic and dihedral cohomologies ofA+(k). Lastly we discuss the relevance of this limiting case to the case of finiten in this situation.Partially supported by NSF grant number MCS-8401718 and a Bantrell Fellowship 相似文献
105.
Abstract— Replication continues in wild-type (but not rad mutant) Caenorhabditis elegans embryos even after exposure to massive fluences of UV radiation. It is of interest to elucidate the mechanism(s) for this "damage-resistant" DNA synthesis. In this study, DNA from unirradiated and UV-irradiated wild-type embryos was examined using the electron microscope. Large fluences of UV radiation (180 J m−2 ) had little effect on either replication bubble size or distances between bubbles in wild-type embryos, indicating that the damage-resistant DNA synthesis was not grossly aberrant. Conversely, UV irradiation significantly decreased center-to-center distances between bubbles in excision-repair-deficient rad-3 embryos. This suggests that the decreased DNA synthesis observed after UV irradiation in rad-3 embryos is due largely to blockage of elongation of DNA synthesis. 相似文献
106.
β′-Phenylsulfonyl α,β-unsaturated ketones, which can be easily converted to unsymmetric dialkenyl ketones, were prepared via ring opening reactions of 2-alkenyl-2-methoxycyclopropyl phenyl sulfones. 相似文献
107.
108.
Shin W Lee SH Shin JW Lee SP Kim Y 《Journal of the American Chemical Society》2003,125(48):14688-14689
We found that CODH is a fascinating enzyme for the electrochemical conversion of CO2 to CO. It could reduce CO2 to CO at -0.57 V vs NHE with approximately 100% current efficiency in 0.1 M phosphate buffer (pH 6.3). Nature's unique structure of C-cluster in CODH would be responsible for the low overpotential and the selective and fast conversion of CO2. The turnover number per C-cluster is 700 h-1, and the pH optimum is 6.3. 相似文献
109.
110.