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排序方式: 共有1318条查询结果,搜索用时 187 毫秒
971.
972.
Dimas K Hatziantoniou S Tseleni S Khan H Georgopoulos A Alevizopoulos K Wyche JH Pantazis P Demetzos C 《Apoptosis : an international journal on programmed cell death》2007,12(4):685-694
Labd-14-ene-8, 13-diol (sclareol) is a labdane-type diterpene, which has demonstrated significant cytotoxic activity against
human leukemic cell lines, but its effect on solid tumor-derived cells is uknown. Here, we demonstrate that addition of sclareol
to cultures of human colon cancer HCT116 cells results in inhibition of DNA synthesis, arrest of cells at the G1 phase of the cell cycle, activation of caspases-8, -9, PARP degradation, and DNA fragmentation, events characteristic of
induction of apoptosis. Intraperitoneal (ip) administration of sclareol alone, at the maximum tolerated dose, was unable to
induce suppression of growth of HCT116 tumors established as xenografts in immunodeficient SCID mice. In contrast, ip administration
of liposome-encapsulated sclareol, following a specific schedule, induced suppression of tumor growth by arresting tumor cell
proliferation as assessed by detecting the presence of the cell proliferation-associated nuclear protein, Ki67, in thin tumor
sections. These findings suggest that sclareol incorporated into liposomes may possess chemotherapeutic potential for the
treatment of colorectal and other types of human cancer. 相似文献
973.
Vogiatzakis N Kekou K Sophocleous C Kitsiou S Mavrou A Bakoula C Kanavakis E 《Molecular biotechnology》2007,37(3):212-219
Many human diseases are caused by small alterations in the genes and in the majority of cases sophisticated protocols are
required for their detection. In this study we estimated the efficacy of an enzymatic protocol, which using a new mismatch-specific
DNA plant endonuclease from celery (CEL family) recognizes and cleaves mismatched alleles between mutant and normal PCR products.
The protocol was standardized on a variety of known mutations, in 11 patients with cystic fibrosis (CF), Fabry’s disease (FD),
steroid 21-hydroxylase deficiency (21-HD) and Duchenne/Becker muscular dystrophy (DMD/BMD). The method does not require special
equipment, labeling or standardization for every PCR product, since conditions of heteroduplex formation and enzyme digestion
are universal for all products. The results showed that the method is rapid, effective, safe, reliable, and very simple, as
the mutations are visualized on agarose or nusieve/agarose gels. The protocol was furthermore evaluated in three DMD patients
with the detection of three alterations which after sequencing, were characterized as disease causative mutations. The proposed
assay, which was applied for the first time in a variety of monogenic disorders, indicates that point mutation identification
is feasible in any conventional molecular lab even for cases, where other techniques have failed. 相似文献
974.
Helena Herr Natalie Kelly Boris Dorschel Marcus Huntemann Karl‐Hermann Kock Linn Sophia Lehnert Ursula Siebert Sacha Viquerat Rob Williams Meike Scheidat 《Ecology and evolution》2019,9(10):5664-5682
This study investigates the distribution of Antarctic minke whales (AMW) in relation to sea ice concentration and variations therein. Information on AMW densities in the sea ice‐covered parts of the Southern Ocean is required to contextualize abundance estimates obtained from circumpolar shipboard surveys in open waters, suggesting a 30% decline in AMW abundance. Conventional line‐transect shipboard surveys for density estimation are impossible in ice‐covered regions, therefore we used icebreaker‐supported helicopter surveys to obtain information on AMW densities along gradients of 0%–100% of ice concentration. We conducted five helicopter surveys in the Southern Ocean, between 2006 and 2013. Distance sampling data, satellite‐derived sea‐ice data, and bathymetric parameters were used in generalized additive models (GAMs) to produce predictions on how the density of AMWs varied over space and time, and with environmental covariates. Ice concentration, distance to the ice edge and distance from the shelf break were found to describe the distribution of AMWs. Highest densities were predicted at the ice edge and through to medium ice concentrations. Medium densities were found up to 500 km into the ice edge in all concentrations of ice. Very low numbers of AMWs were found in the ice‐free waters of the West Antarctic Peninsula (WAP). A consistent relationship between AMW distribution and sea ice concentration weakens the support for the hypothesis that varying numbers of AMWs in ice‐covered waters were responsible for observed changes in estimated abundance. The potential decline in AMW abundance stresses the need for conservation measures and further studies into the AMW population status. Very low numbers of AMWs recorded in the ice‐free waters along the WAP support the hypothesis that this species is strongly dependent on sea ice and that forecasted sea ice changes have the potential of heavily impacting AMWs. 相似文献
975.
Ingrid U Schraufstatter Sophia K Khaldoyanidi Richard G DiScipio 《World journal of stem cells》2015,7(8):1090-1108
The complement pathway is best known for its role in immune surveillance and inflammation. However, its ability of opsonizing and removing not only pathogens, but also necrotic and apoptotic cells, is a phylogenetically ancient means of initiating tissue repair. The means and mechanisms of complement-mediated tissue repair are discussed in this review. There is increasing evidence that complement activation contributes to tissue repair at several levels. These range from the chemo-attraction of stem and progenitor cells to areas of complement activation, to increased survival of various cell types in the presence of split products of complement, and to the production of trophic factors by cells activated by the anaphylatoxins C3a and C5a. This repair aspect of complement biology has not found sufficient appreciation until recently. The following will examine this aspect of complement biology with an emphasis on the anaphylatoxins C3a and C5a. 相似文献
976.
Misfolding of the prion protein at the plasma membrane induces endocytosis, intracellular retention and degradation 总被引:3,自引:0,他引:3
Suramin induces misfolding of the cellular prion protein (PrP(C)) and interferes with the propagation of infectious scrapie prions. A mechanistic analysis of this effect revealed that suramin-induced misfolding occurs at the plasma membrane and is dependent on the proximal region of the C-terminal domain (aa 90-158) of PrP(C). The conformational transition induces rapid internalization, mediated by the unstructured N-terminal domain, and subsequent intracellular degradation of PrP(C). As a consequence, PrP Delta N adopts a misfolded conformation at the plasma membrane; however, internalization is significantly delayed. We also found that misfolding and intracellular retention of PrP(C) can be induced by copper and that, moreover, copper interferes with the propagation of the pathogenic prion protein (PrP(Sc)) in scrapie-infected N2a cells. Our study revealed a quality control pathway for aberrant PrP conformers present at the plasma membrane and identified distinct PrP domains involved. 相似文献
977.
Tegel H Yderland L Boström T Eriksson C Ukkonen K Vasala A Neubauer P Ottosson J Hober S 《Biotechnology journal》2011,6(8):1018-1025
Protein production and analysis in a parallel fashion is today applied in laboratories worldwide and there is a great need to improve the techniques and systems used for this purpose. In order to save time and money, a fast and reliable screening method for analysis of protein production and also verification of the protein product is desired. Here, a micro-scale protocol for the parallel production and screening of 96 proteins in plate format is described. Protein capture was achieved using immobilized metal affinity chromatography and the product was verified using matrix-assisted laser desorption ionization time-of-flight MS. In order to obtain sufficiently high cell densities and product yield in the small-volume cultivations, the EnBase® cultivation technology was applied, which enables cultivation in as small volumes as 150 μL. Here, the efficiency of the method is demonstrated by producing 96 human, recombinant proteins, both in micro-scale and using a standard full-scale protocol and comparing the results in regard to both protein identity and sample purity. The results obtained are highly comparable to those acquired through employing standard full-scale purification protocols, thus validating this method as a successful initial screening step before protein production at a larger scale. 相似文献
978.
979.
Production of activated carbon from bagasse and rice husk by a single-stage chemical activation method at low retention times 总被引:7,自引:1,他引:6
The production of activated carbon from bagasse and rice husk by a single-stage chemical activation method in short retention times (30-60min) was examined in this study. The raw materials were subjected to a chemical pretreatment and were fed to the reactor in the form of a paste (75% moisture). Chemicals examined were ZnCl2, NaOH and H3PO4, for temperatures of 600, 700 and 800 degrees C. Of the three chemical reagents under evaluation only ZnCl2 produced activated carbons with high surface areas. BET surface areas for rice husk were up to 750m2/g for 1:1 ZnCl2:rice husk ratio. BET surface areas for bagasse were up to 674m2/g for 0.75:1 ZnCl2:bagasse ratio. Results were compared to regular two-stage physical activation methods. 相似文献
980.
Tambor JH Ren H Ushinsky S Zheng Y Riemens A St-Francois C Tsang A Powlowski J Storms R 《Applied microbiology and biotechnology》2012,93(1):203-214
The hydrolysis of cellulose into fermentable sugars is a costly and rate-limiting step in the production of biofuels from
renewable feedstocks. Developing new cellulase systems capable of increased cellulose hydrolysis rates would reduce biofuel
production costs. With this in mind, we screened 55 fungal endoglucanases for their abilities to be expressed at high levels
by Aspergillus niger and to hydrolyze amorphous cellulose at rates significantly greater than that obtained with TrCel5A, one of the major endoglucanases
in the Trichoderma reesei cellulase system. This screen identified three endoglucanases, Aureobasidium pullulans ApCel5A, Gloeophyllum trabeum GtCel12A and Sporotrichum thermophile StCel5A. We determined that A. niger expressed the three endoglucanases at relatively high levels (≥0.3 g/l) and that the hydrolysis rate of ApCel5A and StCel5A
with carboxymethylcellulose 4M as substrate was five and two times greater than the T. reesei Cel5A. The ApCel5A, GtCel12A and StCel5A enzymes also demonstrated significant synergy with Cel7A/CbhI, the major exoglucanase
in the T. reesei cellulase system. The three endoglucanases characterized in this study are, therefore, promising candidate endoglucanases
for developing new cellulase systems with increased rates of cellulose saccharification. 相似文献