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41.
Glareh Azadi Anuj Chauhan Anubhav Tripathi 《Protein science : a publication of the Protein Society》2013,22(9):1258-1265
Dilution of protein–surfactant complexes is an integrated step in microfluidic protein sizing, where the contribution of free micelles to the overall fluorescence is reduced by dilution. This process can be further improved by establishing an optimum surfactant concentration and quantifying the amount of protein based on the fluorescence intensity. To this end, we study the interaction of proteins with anionic sodium dodecyl sulfate (SDS) and cationic hexadecyl trimethyl ammonium bromide (CTAB) using a hydrophobic fluorescent dye (sypro orange). We analyze these interactions fluourometrically with bovine serum albumin, carbonic anhydrase, and beta‐galactosidase as model proteins. The fluorescent signature of protein–surfactant complexes at various dilution points shows three distinct regions, surfactant dominant, breakdown, and protein dominant region. Based on the dilution behavior of protein–surfactant complexes, we propose a fluorescence model to explain the contribution of free and bound micelles to the overall fluorescence. Our results show that protein peak is observed at 3 mM SDS as the optimum dilution concentration. Furthermore, we study the effect of protein concentration on fluorescence intensity. In a single protein model with a constant dye quantum yield, the peak height increases with protein concentration. Finally, addition of CTAB to the protein–SDS complex at mole fractions above 0.1 shifts the protein peak from 3 mM to 4 mM SDS. The knowledge of protein–surfactant interactions obtained from these studies provides significant insights for novel detection and quantification techniques in microfluidics. 相似文献
42.
Pandey Gyanendra Krishna Pathak Nilesh Kumar Ji Alok Pathak Hardik Sharma R. P. 《Plasmonics (Norwell, Mass.)》2016,11(5):1343-1349
Plasmonics - In this paper, we have studied the surface enhanced raman scattering (SERS) from a molecule adsorbed on coated and non-coated spherical shape metallic nanoparticles. We have accounted... 相似文献
43.
Sangita Roopak Nilesh Kumar Pathak Alok Ji R. P. Sharma 《Plasmonics (Norwell, Mass.)》2016,11(2):425-432
We suggest numerical method to study the optical response of metal nanostructures. The analysis of optical properties such as scattering and absorption by coated and noncoated nanogeometry has been done using discrete dipole approximation (DDA) method. The core-shell nanogeometry supports surface plasmon resonances, which are highly tunable from 400 to 1100 nm. The tunability of surface plasmon resonance (SPR) highly depends on the structural anisotropy and chosen core-shell material. Further, we have observed that aspect ratio is one of the key parameter to decide the nature and position of the plasmonic peaks and magnitude of optical cross section. We have also shown that coated nanospheroid is a more appropriate geometry as compared to coated nanosphere and noncoated nanospheroid in terms of wide tunability of surface plasmon resonance. The wide tunability in SPR is observed for the effective radii 90 nm core-shell (Au@SiO2) nanospheroid with aspect ratio 0.1. 相似文献
44.
45.
Ratan K. Choudhary Shanti Choudhary Harmanjot Kaur Devendra Pathak 《Animal biotechnology》2016,27(3):182-189
Buffaloes account for more than 56% of total milk production in India. Cyclic remodeling of mammary glands of human, mice, cow, sheep, and goat is determined by mammary stem cells. It is logical to assume that buffalo mammary gland will have mammary stem/progenitor cells. Thus far, no report exists on identification of buffalo mammary stem cells. Hepatocyte nuclear factor 4 alpha (HNF4A) is a candidate marker for hepatic progenitor cells and has recently been suggested as a marker of bovine mammary stem/progenitor cells. We hypothesized that (1) HNF4A identifies putative buffalo mammary stem/progenitor cells and (2) the number of HNF4A-positive cells increases during mastitis. Sixteen buffalo mammary samples were collected from a local slaughterhouse. Hematoxylin and eosin staining were performed on 5-micron thick sections and on the basis of gross examination and histomorphology of the mammary glands, physiological stages of the animals were estimated as non-lactating (n = 4), mastitis (n = 9), and prepubertal (n = 3). In total, 24048 cells were counted (5–10 microscopic fields/animal; n = 16 animals) of which, 40% cells were mammary epithelial cells (MEC) and 60% cells were the stromal cells. The percentage of MEC in non-lactating animals was higher compared to mastitic animals (47.3% vs. 37.3%), which was likely due to loss of MEC in mastitis. HNF4A staining was observed in nuclei of MEC of ducts, alveoli, and stromal cells. Basal location and low frequency of HNF4A-positive MEC (ranges from 0.4–4.5%) were consistent with stem cell characteristics. Preliminary study showed coexpression of HNF4A with MSI1 (a mammary stem cell marker in sheep), suggesting HNF4A was likely to be a putative mammary stem/progenitor cell marker in buffalo. HNF4A-positive MEC (basal and luminal; light and dark stained) tended to be higher in non-lactating than the mastitic animals (8.73 ± 1.71% vs. 4.29 ± 1.19%; P = 0.07). The first hypothesis that HNF4A identify putative mammary stem/progenitor cells was confirmed but the second hypothesis that the number of mammary stem/progenitor cells decreases during mastitis was unsupported. This is the first report outlining the expression of HNF4A and identification of putative mammary stem/progenitor cells in buffalo mammary gland. 相似文献
46.
Jaiswal Rahul Kumar Pandit Nidhi Pathak Nagendra Prasad 《Plasmonics (Norwell, Mass.)》2019,14(6):1539-1546
Plasmonics - In this study, we report a design concept to obtain center frequency and bandwidth reconfigurable spoof surface plasmon polaritons (SSPP) band-pass filter using T-shaped spoof SPP... 相似文献
47.
Shukla Geeta Sharma Anuj Bhatia Ruchika Sharma Mridul 《Probiotics and antimicrobial proteins》2019,11(1):165-174
Probiotics and Antimicrobial Proteins - Giardiasis is a re-emerging infectious disease with outbreaks reported globally specially in children and malnourished individuals leading to malabsorption,... 相似文献
48.
49.
Comparison of Performance Parameters of Conventional and Nano-plasmonic Fiber Optic Sensors 总被引:1,自引:1,他引:0
A detailed comparative analysis is carried out between two fiber optic surface plasmon resonance (SPR) sensor probes with
different bimetallic configurations. One consists of a step arrangement of thin layers of silver and gold. Another one consists
of alloy layer formed of spherical silver and gold nanoparticles. Their sensitivity and detection accuracy are compared. Better
configuration is predicted with proper logics and rationales. 相似文献
50.
Ian A. Kent Qiao Zhang Aditya Katiyar Yuan Li Shreya Pathak Richard B. Dickinson Tanmay P. Lele 《Journal of cellular physiology》2019,234(11):20675-20684
Breast cancer nuclei have highly irregular shapes, which are diagnostic and prognostic markers of breast cancer progression. The mechanisms by which irregular cancer nuclear shapes develop are not well understood. Here we report the existence of vertical, apical cell protrusions in cultured MDA-MB-231 breast cancer cells. Once formed, these protrusions persist over time scales of hours and are associated with vertically upward nuclear deformations. They are absent in normal mammary epithelial cells (MCF-10A cells). Microtubule disruption enriched these protrusions preferentially in MDA-MB-231 cells compared with MCF-10A cells, whereas inhibition of nonmuscle myosin II (NMMII) abolished this enrichment. Dynamic confocal imaging of the vertical cell and nuclear shape revealed that the apical cell protrusions form first, and in response, the nucleus deforms and/or subsequently gets vertically extruded into the apical protrusion. Overexpression of lamin A/C in MDA-MB-231 cells reduced nuclear deformation in apical protrusions. These data highlight the role of mechanical stresses generated by moving boundaries, as well as abnormal nuclear mechanics in the development of abnormal nuclear shapes in breast cancer cells. 相似文献