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641.
Hymenidium apiolens and H. pilosum have been recorded to co-occur in the Himalayas, and it was found difficult to distinguish between them in the field. In this study, we reconstructed the phylogeny and estimated the genetic distance between individuals of H. apiolens, H. pilosum and related species based on nuclear ITS sequences, and rpl16 and rps16 introns, to determine the relationship between H. apiolens and H. pilosum. The analyses suggest that H. apiolens and H. pilosum are nested together, and that the ratio of genetic distance between them is smaller than that between individuals of Chamaesium spatuliferum, Hansenia forbesii or Ligusticum acuminatum. Furthermore, we found similar morphological characteristics of bracteoles, rays, petals and mericarps in H. apiolens and H. pilosum. Consequently, both molecular and morphological evidence supports that Hymenidium pilosum is a synonym of H. apiolens. 相似文献
642.
Ligands can be captured by a surface target through either direct bulk diffusion or surface diffusion following reversible adsorption to the surface. We have solved a steady state boundary value problem for a perfect sink disk target in the surface, taking into account bulk and surface diffusion coefficients D and Ds and adsorption/desorption kinetic rate constants ka and kd at non-target regions. Solutions have been successfully found by numerical computation. The results show that the rate of capture from the surface depends non-linearly on Ds, D, ka, kd and geometrical dimensions. In particular, we demonstrate that not only is the non-target region equilibrium constant Keq (= ka/kd) important in determining the rate of capture from the surface, but so are the kinetic rate constants ka and kd separately. In all cases, the surface adsorption/diffusion combination enhances the total rate of capture. The results should be useful for predicting reaction rates of biological membrane bound receptor clusters and substrate-immobilized enzymes. 相似文献
643.
Han Liu Jiping Yue He Huang Xuewen Gou Shao-Yu Chen Yingming Zhao Xiaoyang Wu 《The Journal of biological chemistry》2015,290(52):30771-30782
Cell migration is a fundamental cellular process requiring integrated activities of the cytoskeleton, membrane, and cell/extracellular matrix adhesions. Many cytoskeletal activities rely on microtubule filaments. It has been speculated that microtubules can serve as tracks to deliver proteins essential for focal adhesion turnover. Three microtubule end-binding proteins (EB1, EB2, and EB3) in mammalian cells can track the plus ends of growing microtubules. EB1 and EB3 together can regulate microtubule dynamics by promoting microtubule growth and suppressing catastrophe, whereas, in contrast, EB2 does not play a direct role in microtubule dynamic instability, and little is known about the cellular function of EB2. By quantitative proteomics, we identified mammalian HCLS1-associated protein X-1 (HAX1) as an EB2-specific interacting protein. Knockdown of HAX1 and EB2 in skin epidermal cells stabilizes focal adhesions and impairs epidermal migration in vitro and in vivo. Our results further demonstrate that cell motility and focal adhesion turnover require interaction between Hax1 and EB2. Together, our findings provide new insights for this critical cellular process, suggesting that EB2 association with Hax1 plays a significant role in focal adhesion turnover and epidermal migration. 相似文献
644.
Goué Nadia Montiel Grégory Levert Isabelle Gaudet Muriel Jay-Allemand Christian Label Philippe 《Trees - Structure and Function》2003,17(4):316-324
Trees - Improved wood production is a major aim for walnut forests and especially for hybrid walnut (Juglans nigra×Juglans regia). This paper presents the first report describing the structure... 相似文献
645.
Li Yun-Cheng Zeng Wei-Yi Gou Min Sun Zhao-Yong Xia Zi-Yuan Tang Yue-Qin 《Applied microbiology and biotechnology》2017,101(20):7741-7753
Applied Microbiology and Biotechnology - It is of utmost importance to construct industrial xylose-fermenting Saccharomyces cerevisiae strains for lignocellulosic bioethanol production. In this... 相似文献
646.
Xiaomei Gou Peter B. Reich Liping Qiu Mingan Shao Gehong Wei Jingjing Wang Xiaorong Wei 《Global Change Biology》2023,29(14):4028-4043
Leguminous plants are an important component of terrestrial ecosystems and significantly increase soil nitrogen (N) cycling and availability, which affects productivity in most ecosystems. Clarifying whether the effects of legumes on N cycling vary with contrasting ecosystem types and climatic regions is crucial for understanding and predicting ecosystem processes, but these effects are currently unknown. By conducting a global meta-analysis, we revealed that legumes increased the soil net N mineralization rate (Rmin) by 67%, which was greater than the recently reported increase associated with N deposition (25%). This effect was similar for tropical (53%) and temperate regions (81%) but was significantly greater in grasslands (151%) and forests (74%) than in croplands (−3%) and was greater in in situ incubation (101%) or short-term experiments (112%) than in laboratory incubation (55%) or long-term experiments (37%). Legumes significantly influenced the dependence of Rmin on N fertilization and experimental factors. The Rmin was significantly increased by N fertilization in the nonlegume soils, but not in the legume soils. In addition, the effects of mean annual temperature, soil nutrients and experimental duration on Rmin were smaller in the legume soils than in the nonlegume soils. Collectively, our results highlighted the significant positive effects of legumes on soil N cycling, and indicated that the effects of legumes should be elucidated when addressing the response of soils to plants. 相似文献
647.
Six novel 2‐(benzylcarbamoyl)phenyl derivatives were synthesized and characterized by 1H‐NMR, mass spectrometry, infrared spectra and elemental analysis. Their europium complexes were prepared and characterized by elemental analysis, EDTA titrimetric analysis, IR and UV spectra as well as molar conductivity measurements. The luminescence properties of these complexes were investigated and results show that 2‐(benzylcarbamoyl)phenyl derivatives possess high selectivity and good coordination with the europium ion. Complex Eu‐2‐(benzylcarbamoyl)phenyl‐2‐phenylacetate showed green luminescence that was emitted by the ligand of 2‐(benzylcarbamoyl)phenyl‐2‐phenylacetate, while other complexes showed the characteristic red luminescence of europium ion and also possessed high luminescence intensity. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
648.
649.
Bao-Di Gou Yang Liu Yu-Xi Gao Kun Tang Lei Zheng Yi-Dong Zhao Tian-Lan Zhang 《Journal of structural biology》2019,205(1):41-47
The total calcium (tCa) in blood serum comprises free Ca2+ ions (fCa), protein-bound calcium (prCa), and complexed calcium by small anions (cCa). The cCa fraction, in addition to fCa, has been indicated to have some physiological activity. However, there is little evidence for the structure of its constituents. Here we report an ex vivo detection of the cCa constituents by synchrotron X-ray absorption near-edge structure spectroscopy. We collected the data directly on rat blood serum and, by making use of the reference samples, derived a spectrum that exhibits the features of cCa constituents. Among the features are those of the complexes of calcium phosphate and calcium carbonate. The detected complexes in the cCa fraction are mainly Ca(η2-HPO4)(H2O)4 and Ca(η1-HCO3)(H2O)5+, in which HPO42? and HCO3? serve as bidentate and unidentate ligands, respectively. The remained H2O molecules on the coordination sphere of Ca2+ enable these complexes to behave partially like aquated Ca2+ ions in protein-binding. Besides, as the dominant part of prCa, albumin-bound calcium (albCa) exhibits a spectrum that closely resembles that of fCa, indicating weak interactions between the protein carboxyl groups and calcium. The weak-bound cCa and albCa, along with fCa and the relevant anions, compose a local chemical system that could play a role in maintaining the calcium level in blood. 相似文献
650.