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991.
992.
Time-dependent yields of the most important products of water radiolysis , •OH, H•, H3O+, H2, OH− and H2O2 have been calculated for 60Co-photons, electrons, protons, helium- and carbon-ions incident onto water. G values have been evaluated for the interval from 1 ps to 1 μs after initial energy deposition as a function of time, as well
as after 1 ns and at the end of the chemical stage as a function of linear energy transfer (LET), covering an interval from
approximately 0.2 up to 750 keV/μm by means of different particle types. In this work, the modules of the biophysical Monte
Carlo track structure code PARTRAC dealing with the simulation of prechemical and chemical stages have been improved to extend
interaction data sets for heavier ions. Among other newly selected parameter values, the thermalisation distance between the
point of generation and hydration of subexcitation electrons has been adopted from recent data in the literature. As far as
data from the literature are available, good agreement has been found with the calculated time- and LET-dependent yields in
this work, supporting the selection of the revised parameter values. 相似文献
993.
Beyond vessels: occurrence and regional clustering of vascular endothelial (VE-)cadherin-containing junctions in non-endothelial cells 总被引:1,自引:1,他引:0
Judit Boda-Heggemann Anne Régnier-Vigouroux Werner W. Franke 《Cell and tissue research》2009,335(1):49-65
The genes encoding transmembrane glycoproteins of the cadherin family, i.e., the Ca2+-dependent cell-cell adhesion molecules, are typically expressed in cell-type- or cell-lineage-specific patterns. One of them,
vascular endothelial (VE)-cadherin, is widely considered to be specific for vascular endothelia in which it is either the
sole or the predominant cadherin, often co-existing with N-cadherin. This specificity of VE-cadherin for vascular endothelial
cells is important not only in blood and lymph vessel biology and medicine, but also for cell-type-based diagnoses, notably
those of metastatic tumors. Surprisingly, however, we have recently noted the frequent synthesis, surface exposure, and junction
assembly of VE-cadherin in certain other cells, in which this glycoprotein is clustered into adherens junctions (AJs), either
alone or in combination with N-cadherin and/or cadherin-11. Such cells include mammalian astrocytes and glioma, probably mostly
astrocytoma cells growing in culture, and a specific subtype of astrocytoma in situ. Moreover, VE-cadherin synthesis and AJ
assembly, plus the regional clustering of such AJs in certain domains, are not clonally fixed but can appear again and again
in cells of the progeny of cloned homogeneous-appearing individual cells, thus resulting in clonal cell colonies that are
often heterogeneous in their cadherin junction patterns. We discuss the constitutive presence of VE-cadherin in some non-endothelial
cells with respect to certain architectural features and possible physiological and pathogenic functions of the cells, and
in comparison with recent reports of VE-cadherin-positive melanomas.
This work was supported in part by the Deutsche Krebshilfe (grant 10 2049 Fr1) and the German Ministry for Research and Technology
(Program Regenerative Medicine, START-MSC consortium). 相似文献
994.
Jennifer D. Lewis Laura A. Sullivan Jennifer A. Byrne Werner de Riese Robert K. Bright 《Cancer immunology, immunotherapy : CII》2009,58(8):1337-1349
Tumor protein D52 (TPD52) is involved in cellular transformation, proliferation and metastasis. TPD52 over expression has been demonstrated in several cancers including prostate, breast, and ovarian carcinomas. Murine TPD52 (mD52) has been shown to induce anchorage independent growth in vitro and metastasis in vivo, and mirrors the function and normal tissue expression patterns of the human orthologue of TPD52. We believe TPD52 represents a self, non-mutated tumor associated antigen (TAA) important for maintaining a transformed and metastatic cellular phenotype. The transgenic adeno-carcinoma of the mouse prostate (TRAMP) model was employed to study mD52 as a vaccine antigen. Naïve mice were immunized with either recombinant mD52 protein or plasmid DNA encoding the full-length cDNA of mD52. Following immunization, mice were challenged with a subcutaneous, tumorigenic dose of mD52 positive, autochthonous TRAMP-C1 tumor cells. Sixty percent of mice were tumor free 85 days post challenge with TRAMP-C1 when immunized with mD52 as a DNA-based vaccine admixed with soluble granulocyte-macrophage colony stimulating factor (GM-CSF). Survivors of the initial tumor challenge rejected a second tumor challenge given in the opposite flank approximately 150 days after the first challenge, and remained tumor free for more than an additional 100 days. The T cell cytokine secretion patterns from tumor challenge survivors indicated that a TH1-type cellular immune response was involved in tumor protection. These data suggest that mD52 vaccination induced a memory, cellular immune response that resulted in protection from murine prostate tumors that naturally over express mD52 protein. 相似文献
995.
Tropospheric O3 and deposition of reactive N threaten the composition and function of natural and semi-natural vegetation even in remote
regions. However, little is known about effects of these pollutants individually or in combination on plant species in alpine
habitats. We analyzed 11 frequent plant species of a subalpine Geo-Montani-Nardetum pasture exposed at 2,000 m a.s.l. in the Swiss Alps during 3 years using a factorial free-air exposure system with three
concentrations of O3 and five rates of N application. The aim was to detect subtle effects on leaf chlorophyll and N concentrations, leaf weight,
specific leaf area (SLA), and δ18O and δ13C as proxies for gas exchange. We expected that the species’ responsiveness to O3 and N would be related to their functional traits and that N-induced changes in these traits would modify the species’ response
to O3 via increased growth and higher leaf conductance (g
s). Most species reacted to N supply with the accumulation of N and chlorophyll, but with no change in SLA, g
s, and growth, except Carex sempervirens which showed increased water use efficiency and leaf weight. Elevated O3 reduced g
s
in most species, but this was not related to a reduction in leaf weight, which was recorded in half of the species. Contrary to our expectation, the magnitude of the response to both O3 and N was not related to species-specific traits such as SLA or g
s. No pronounced O3 × N interactions were observed. In conclusion, since for most species neither N nor gas exchange limited growth, their short-term
response to O3 and N and to their combination was small. O3 × N interactive effects are expected to be more pronounced in habitats where species are more responsive to N due to favorable
growth conditions in terms of nutrient availability and temperature.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
996.
Mathias Harzhauser Markus Reuter Werner E. Piller Björn Berning Andreas Kroh Oleg Mandic 《Pal?ontologische Zeitschrift》2009,83(3):333-372
Shallow marine gastropod assemblages from Chattian, Aquitanian and Burdigalian sections in the Indian Kutch Basin are described.
They provide insight into the composition and biogeographic relations of the gastropod assemblages at this junction between
the Western Tethys and Proto-Indo-Pacific Ocean. For the first time, an improved biostratigraphy allows a clear separation
of the assemblages, especially for the hitherto undifferentiated Early Miocene faunas. Throughout the Oligocene, about one-third
of the species are also frequently found in the Western Tethys, documenting a passable Tethyan Seaway for nearshore molluscs.
A considerable provincialism is evident as well. The expected turnover during the Early Miocene, due to the closing of the
Tethyan Seaway, is reflected in the Miocene assemblages. Surprisingly, however, the cut appears very early, i.e. already during
the Aquitanian, when the West–East interrelation drops to zero despite the passage having been open during this interval.
In contrast, the Burdigalian assemblages witness a minor re-appearance of Western Tethys taxa, suggesting the re-establishment
of rather ineffective migration pathways prior to the final closure of the Tethyan Seaway. Cerithium bermotiense and Lyria (Indolyria) maniyaraensis are introduced as new species. 相似文献
997.
Fuss W 《Chirality》2009,21(2):299-304
Life did not emerge in a single step. In chemical evolution, the first formation of a self-replicating molecule was probably one of the most critical bottlenecks, which was overcome only with a very low probability. If only one such event was successful, present-day life originates from a single molecule. In this case, homochirality in DNA and RNA is explained almost without further assumptions. By contrast, the enantiomer excess, produced by the deterministic mechanisms suggested so far, is smaller than the statistical standard deviation, unless the postulated initial number of molecules is very--in some mechanisms unreasonably--large. A certain chiral nonuniformity of natural monosaccharides other than (deoxy)ribose supports the idea that homochirality originates not from such small molecules but from an early RNA-like oligomer. This nonuniformity seems also hard to explain by any deterministic mechanism. 相似文献
998.
The discovery of a Neolithic glacier mummy (dated to 3300–3100 cal b.c.) on a remote site of an Alpine pass at 3,200 m in the Ötztal Mountains is still puzzling. In the initial phase of the Iceman research, four hypotheses were suggested to explain the find in its entirety. The speculations vary from a hunter or warrior to a shaman, a miner or a shepherd. None of these proposals is accepted or corroborated by archaeological findings, but on the basis of palynological investigations conducted in the vicinity of the discovery site the assumption that the Iceman was involved in an early form of transhumance has now gained general acceptance. Concerning this assumption we present in this paper a recent study conducted on about a hundred caprine (sheep/goat or ibex/chamois) dung pellets recovered from the find spot of the Iceman and which were dated from 5400 to 2000 cal b.c. The approach was to determine through plant remains from these faeces whether they were droppings derived from animals grazing in anthropogenic habitats at low altitudes or in alpine grasslands. The former case would suggest they were livestock, the latter game. The results showed that all droppings derive from animals grazing at high altitudes. 相似文献
999.
1000.
Albert Enz Dominik Feuerbach Mathias U. Frederiksen Conrad Gentsch Konstanze Hurth Werner Müller Joachim Nozulak Bernard L. Roy 《Bioorganic & medicinal chemistry letters》2009,19(5):1287-1291
A novel class of α7 nicotinic acetylcholine receptor (nAChR) agonists has been discovered through high-throughput screening. The cis γ-lactam scaffold has been optimized to reveal highly potent and selective α7 nAChR agonists with in vitro activity and selectivity and with good brain penetration in mice. 相似文献