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91.
Bioprospecting is the exploration of biodiversity for new resources of social and commercial value. It is carried out by a wide range of established industries such as pharmaceuticals, manufacturing and agriculture as well as a wide range of comparatively new ones such as aquaculture, bioremediation, biomining, biomimetic engineering and nanotechnology. The benefits of bioprospecting have emerged from such a wide range of organisms and environments worldwide that it is not possible to predict what species or habitats will be critical to society, or industry, in the future. The benefits include an unexpected variety of products that include chemicals, genes, metabolic pathways, structures, materials and behaviours. These may provide physical blueprints or inspiration for new designs. Criticism aimed at bioprospecting has been addressed, in part, by international treaties and legal agreements aimed at stopping biopiracy and many activities are now funded by agencies that require capacity-building and economic benefits in host countries. Thus, much contemporary bioprospecting has multiple goals, including the conservation of biodiversity, the sustainable management of natural resources and economic development. Ecologists are involved in three vital ways: first, applying ecological principles to the discovery of new resources. In this context, natural history becomes a vast economic database. Second, carrying out field studies, most of them demographic, to help regulate the harvest of wild species. Third, emphasizing the profound importance of millions of mostly microscopic species to the global economy. 相似文献
92.
Shi-bin Wang Dai-zheng Liao Zong-hui Jiang Shi-ping Yan 《Inorganica chimica acta》2005,358(9):2595-2601
Based on the complex ligand (CuL H2L = 2,3-dioxo-5,6:15,16-dibenzo-1,4,8,13-tetraazacyclotetradeca-7,13-diene), which includes macrocyclic oxamido bridge, three trinuclear complexes were prepared. They are of the formula [(CuL)2M(ClO4)2] (M = Co(1), Ni(2)) and [(CuL)2Zn(CH3OH)2] · (ClO4)2 (3). The crystal structures of the three complexes have been determined and the M(II) of the three complexes all exist on the mirror plane. Complex 1 is the first Cu-Co complex bridged by oxamido. Their magnetic properties were studied by susceptibility versus temperature measurement, the best fitting of the experimental data led to J = −28.12 cm−1 for 1, J = −42.88 cm−1 for 2, and J = −2.13 cm−1 for 3. 相似文献
93.
Conclusion The summary is that the high humidity impaired the disintegrant property of α-cellulose in all 3 tablets tested. Tablets of
aspirin, which is the more hygroscopic drug, were also more sensitive to the humidity effect, while tablets of chloroquine
phosphate, which is a water-soluble drug, were the least sensitive to the humidity effect. The results permit the conclusion
that moisture uptake with subsequent gelling of the α-cellulose is the mechanism of impairment of its disintegrant property.
The tablets would not normally be stored under an RH as high as 100%, nevertheless, the results of the accelerated stability
study have underscored the need to protect tablets containing α-cellulose as disintegrant from moisture.
Published: August 10, 2005 相似文献
94.
Manjula BN Tsai AG Intaglietta M Tsai CH Ho C Smith PK Perumalsamy K Kanika ND Friedman JM Acharya SA 《The protein journal》2005,24(3):133-146
PEGylation induced changes in molecular volume and solution properties of HbA have been implicated as potential modulators of its vasoconstrictive activity. However, our recent studies with PEGylated Hbs carrying two PEG chains/Hb, have demonstrated that the modulation of the vasoconstrictive activity of Hb is not a direct correlate of the molecular volume and solution properties of the PEGylated Hb and implicated a role for the surface charge and/or the pattern of surface decoration of Hb with PEG. HbA has now been modified by thiolation mediated maleimide chemistry based PEGylation that does not alter its surface charge and conjugates multiple copies of PEG5K chains. This protocol has been optimized to generate a PEGylated Hb, (SP-PEG5K)6-Hb, that carries ~six PEG5K chains/Hb – HexaPEGylated Hb. PEGylation increased the O2 affinity of Hb and desensitized the molecule for the influence of ionic strength, pH, and allosteric effectors, presumably a consequence of the hydrated PEG-shell generated around the protein. The total PEG mass in (SP-PEG5K)6-Hb, its molecular volume, O2 affinity and solution properties are similar to that of another PEGylated Hb, (SP-PEG20K)2-Hb, that carries two PEG20K chains/Hb. However, (SP-PEG5K)6-Hb exhibited significantly reduced vasoconstriction mediated response than (SP-PEG20K)2-Hb. These results demonstrate that the enhanced molecular size and solution properties achieved through the conjugation of multiple copies of small PEG chains to Hb is more effective in decreasing its vasoconstrictive activity than that achieved through the conjugation of a comparable PEG mass using a small number of large PEG chains. 相似文献
95.
96.
在 83K 和 160K 两个温度下,通过激发波长对荧光发射谱的影响研究了光系统II中核心复合物的荧光光谱特性。用不同波长的光激发,核心复合物的发射谱的最大发射峰值不变,用 480、489、495 和 507nm 的光分别激发核心复合物,其光谱最大峰值处的荧光强度随不同激发波长下β-胡萝卜素分子的吸收强度的增大而降低,在长波长区域光谱的变化依赖于首先被激发的色素分子。所以,激发波长的不同影响着核心复合物中能量传递的途径。通过高斯解析,分析出核心复合物中至少存在有 7组叶绿素a组分,它们是Chla660,Chla670,Chla680,Chla682,Chla684,Chla687和Chla690。 相似文献
97.
98.
99.
Three compounds, [(CH3)2NH2][M3(BTC)(HCOO)4(H2O)]·H2O (M = Mn (1), Co (2), Ni (3), H3BTC = 1,3,5-benzenetricarboxylic acid), were synthesized under hydrothermal conditions and were characterized by single crystal and powder X-ray diffraction, IR spectra, elemental analysis, coupled TG-MS and magnetic measurements. Compounds 1-3 are isostructural analogues and crystallize in monoclinic space group P21/c. Each metal ion in these compounds connects to six oxygen atoms to form a MO6 octahedron. Six MO6 octahedra link to each other to form a corner-shared hexameric M6 cluster, which is linked by BTC ligands to form two-dimensional layers. The two-dimensional layers are further connected by formic ions to form a three-dimensional network with channels, where (CH3)2NH2+ ions and water molecular are located. Magnetic measurements indicate that anti-ferromagnetic ordering occurs at low temperature for these compounds. 相似文献
100.
Dong-Ying Du 《Inorganica chimica acta》2010,363(14):3823-3831
A series of inorganic-organic hybrid compounds built from bis(undecatungstophosphate) lanthanates and copper-complexes, namely, H8[Cu(en)2H2O]4[Cu(en)2]{[Cu(en)2][La(PW11O39)2]}2·18H2O (1), H6[Na2(en)2(H2O)5][Cu(en)2H2O]4[Cu(en)2]{[Cu(en)2][Ce(PW11O39)2]}2·16H2O (2), H6[Na2(en)2(H2O)5][Cu(en)2H2O]4[Cu(en)2]{[Cu(en)2][Pr(PW11O39)2]}2·18H2O (3), H6[Na2(en)2(H2O)4][Cu(en)2H2O]4[Cu(en)2]{[Cu(en)2][Nd(PW11O39)2]}2·14H2O (4), H6[Na2(en)2(H2O)5][Cu(en)2H2O]4[Cu(en)2]{[Cu(en)2][Sm(PW11O39)2]}2·20H2O (5), and H7[Cu(en)2]2[Sm(PW11O39)2]·10H2O (6) (where en = 1,2-ethylenediamine), have been prepared. In these compounds, two lacunary [PW11O39]7− anions sandwich an eight-coordinated Ln(III) cation to yield [Ln(PW11O39)2]11− anion in a twisted square anti-prismatic geometry, which is further bridged by [Cu(en)2]2+ fragments to generate a 1D zigzag-like chain. In 1-6, the coordination bond interactions and weak interactions between adjacent 1D chains play an important role in the zigzagging distances and angles of different 1D chains. The magnetic studies indicate that antiferromagnetic interactions exist in compounds 1, 2 and 4. 相似文献