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941.
Background
The evolutionary history of the Asian colobines is less understood. Although monophyly of the odd-nosed monkeys was recently confirmed, the relationships among the langur genera Presbytis, Semnopithecus and Trachypithecus and their position among Asian colobines remained unclear. Moreover, in Trachypithecus various species groups are recognized, but their affiliations are still disputed. To address these issues, mitochondrial and Y chromosomal sequence data were phylogenetically related and combined with presence/absence analyses of retroposon integrations. 相似文献942.
The intentional introduction of red king crab, Paralithodes camtschatica (Tilesius, 1815) in the Barents Sea represent one of a few successful cases and one that now supports a commercial fishery.
Introductions of alien species into new environments are often associated with genetic bottlenecks, which cause a reduction
in the genetic variation, and this could be important for the spreading potential of the species in the Atlantic Ocean. Red
king crab samples collected in the Varangerfjord located on the Barents Sea (northern Norway) were compared with reference
crab samples collected from the Bering Sea and Kamchatka regions in the Pacific Ocean. All samples were screened for eleven
microsatellite loci, based on the development of species-specific primers. The observed number of alleles per locus was similar,
and no reduction in genetic variation, including gene diversity and allelic richness, was detected between the Varangerfjord
sample and the reference sample from Okhotsk Sea near Kamchatka, indicating no genetic bottlenecking at least for the microsatellite
loci investigated. The same results were found in comparison with the sample from Bering Sea. The level of genetic differentiation
among the samples, measured as overall F
ST
across all loci, was relatively low (0.0238) with a range of 0.0035–0.1000 for the various loci investigated. The largest
pairwise F
ST
values were found between the Bering Sea and Varangerfjord/Barents Sea samples, with a value of 0.0194 across all loci tested.
The lowest value (0.0101) was found between the Varangerfjord and Kamchatka samples. Genetic differentiation based on exact
tests on allele frequencies revealed highly significant differences between all pairwise comparisons. The high level of genetic
variation found in the Varangerfjord/Barents Sea sample could be of significance with respect to further spreading of the
species to other regions in the North Atlantic Ocean. 相似文献
943.
Pott C Ren X Tran DX Yang MJ Henderson S Jordan MC Roos KP Garfinkel A Philipson KD Goldhaber JI 《American journal of physiology. Cell physiology》2007,292(2):C968-C973
In cardiac-specific Na+-Ca2+ exchanger (NCX) knockout (KO) mice, the ventricular action potential (AP) is shortened. The shortening of the AP, as well as a decrease of the L-type Ca2+ current (ICa), provides a critical mechanism for the maintenance of Ca2+ homeostasis and contractility in the absence of NCX (Pott C, Philipson KD, Goldhaber JI. Excitation-contraction coupling in Na+-Ca2+ exchanger knockout mice: reduced transsarcolemmal Ca2+ flux. Circ Res 97: 12881295, 2005). To investigate the mechanism that underlies the accelerated AP repolarization, we recorded the transient outward current (Ito) in patch-clamped myocytes isolated from wild-type (WT) and NCX KO mice. Peak Ito was increased by 78% and decay kinetics were slowed in KO vs. WT. Consistent with increased Ito, ECGs from KO mice exhibited shortened QT intervals. Expression of the Ito-generating K+ channel subunit Kv4.2 and the K+ channel interacting protein was increased in KO. We used a computer model of the murine AP (Bondarenko VE, Szigeti GP, Bett GC, Kim SJ, and Rasmusson RL. Computer model of action potential of mouse ventricular myocytes. Am J Physiol Heart Circ Physiol 287: 13781403, 2004) to determine the relative contributions of increased Ito, reduced ICa, and reduced NCX current (INCX) on the shape and kinetics of the AP. Reduction of ICa and elimination of INCX had relatively small effects on the duration of the AP in the computer model. In contrast, AP repolarization was substantially accelerated when Ito was increased in the computer model. Thus, the increase in Ito, and not the reduction of ICa or INCX, is likely to be the major mechanism of AP shortening in KO myocytes. The upregulation of Ito may comprise an important regulatory mechanism to limit Ca2+ influx via a reduction of AP duration, thus preventing Ca2+ overload in situations of reduced myocyte Ca2+ extrusion capacity. genetically altered mice; cardiac myocytes; short QT interval; transient outward current 相似文献
944.
Danielsson C Azarbayjani F Sköld AC Sjögren N Danielsson BR 《Birth defects research. Part A, Clinical and molecular teratology》2007,79(8):595-603
BACKGROUND: The antiepileptic drugs (AEDs) phenytoin, phenobarbital, dimethadione, and carbamazepine cause a similar pattern of malformations in humans, with an increased risk after polytherapy. The teratogenicity has been linked to cardiac rhythm disturbances and hypoxic damage as a consequence of their common potential to inhibit a specific potassium ion current (IKr). The IKr is of major importance for embryonic cardiac repolarization and rhythm regulation. This study investigated whether these AEDs cause irregular rhythm and if various combinations of AEDs result in higher arrhythmia risk than exposure to a single AED. METHODS: The effects on heart rhythm of a single AED (monotherapy), and of various combinations (polytherapy) of AEDs, in gestational day 10 C57BL mouse embryos in culture were analyzed and graphically illustrated during a 25 s recording with a digitalization technique. RESULTS: All of the studied AEDs caused increased intervals between heartbeats (resulting in bradycardia) and large variations in the interval between heartbeats (resulting in irregular rhythm) in a concentration-dependent manner in cultured mouse embryos. Dimethadione caused irregular rhythm at concentrations within and phenytoin slightly above the therapeutic ranges. Polytherapy resulted in more substantial prolongation of the mean interval between heartbeats (>60 ms) than monotherapy at clinically relevant concentrations. CONCLUSIONS: The results suggest that polytherapy more than monotherapy causes substantial prolongation of the cardiac repolarization, a marker associated with high risk of developing irregular rhythm during longer exposure periods (days to months). This supports the idea that the increased risk for malformations following polytherapy is linked to an increased risk for cardiac rhythm disturbances. 相似文献
945.
Akendengue B Roblot F Loiseau PM Bories C Ngou-Milama E Laurens A Hocquemiller R 《Phytochemistry》2002,59(8):885-888
Bioguided-fractionation of a CH(2)Cl(2) extract of the stems of Uvaria klaineana (Annonaceae) led to isolation of klaivanolide, a novel bisunsaturated 7-membered lactone (5-acetoxy-7-benzoyloxymethyl-7H-oxepin-2-one), together with benzyl benzoate. Klaivanolide showed potent in vitro antileishmanial activity against both sensitive and amphotericin B-resistant promastigote forms of Leishmania donovani with IC(50) values of 1.75 and 3.12 microM, respectively. The compound also showed in vitro trypanocidal activity against trypomastigote forms of Trypanosoma brucei brucei GVR 35. Its structure was established by 1D and 2D NMR and other spectroscopic techniques. 相似文献
946.
Androgen receptor phosphorylation. Regulation and identification of the phosphorylation sites 总被引:1,自引:0,他引:1
Gioeli D Ficarro SB Kwiek JJ Aaronson D Hancock M Catling AD White FM Christian RE Settlage RE Shabanowitz J Hunt DF Weber MJ 《The Journal of biological chemistry》2002,277(32):29304-29314
Activation of signal transduction kinase cascades has been shown to alter androgen receptor (AR) activity. Although it has been suggested that changes in AR phosphorylation might be directly responsible, the basal and regulated phosphorylations of the AR have not been fully determined. We have identified the major sites of AR phosphorylation on ARs expressed in COS-1 cells using a combination of peptide mapping, Edman degradation, and mass spectrometry. We describe the identification of seven AR phosphorylation sites, show that the phosphopeptides seen with exogenously expressed ARs are highly similar to those seen with endogenous ARs in LNCaP cells and show that specific agonists differentially regulate the phosphorylation state of endogenous ARs in LNCaP prostate cancer cells. Treatment of LNCaP cells with the synthetic androgen, R1881, elevates phosphorylation of serines 16, 81, 256, 308, 424, and 650. Ser-94 appears constitutively phosphorylated. Forskolin, epidermal growth factor, and phorbol 12-myristate 13-acetate increase the phosphorylation of Ser-650. The kinetics of phosphorylation of most sites in response to hormone or forskolin is temporally delayed, reaching a maximum at 2 h post-stimulation. The exception is Ser-81, which continues to display increasing phosphorylation at 6 h. These data provide a basis for analyzing mechanisms of cross-talk between growth factor signaling and androgen in prostate development, physiology, and cancer. 相似文献
947.
Christian Reuter Mona Alzheimer Heike Walles Tobias A. Oelschlaeger 《Cellular microbiology》2018,20(2)
The human gastrointestinal tract is a complex ecosystem in which epithelial cells and microorganisms of the intestinal microbiota live in symbiosis. Certain members of the microbiota, in particular Escherichia coli strains of the B2 phylotype, carry the polyketide synthase‐island encoding the genotoxin colibactin. Colibactin is a nonribosomal peptide or polyketide‐nonribosomal peptide hybrid of still unsolved structure, which induces DNA double strand breaks (DSBs) in eukaryotic cells. However, direct contact between live bacteria and host cell is required in order to elicit these genotoxic effects. In this study, we used a variety of cell culture models, among them, a 3D cell culture approach based on decellularised small intestinal submucosa, to investigate whether the intestinal mucus layer has the potential to interfere with colibactin activity. We demonstrate that the expression of mucins and the formation of an adherent mucus layer significantly increased with increasing complexity of cell culture. Moreover, we show that the presence of an adherent mucus layer on epithelial cells attenuates the genotoxic activity of colibactin, by preventing the induction of DNA‐DSBs. Removal of the adherent mucus layer restored the occurrence of DNA‐DSBs. 相似文献
948.
949.
Josef Marksteiner Imrich Blasko Georg Kemmler Therese Koal Christian Humpel 《Metabolomics : Official journal of the Metabolomic Society》2018,14(1):1
Introduction
There is still a clear need for a widely available, inexpensive and reliable method to diagnose Alzheimer’s disease (AD) and monitor disease progression. Liquid chromatography–mass spectrometry (LC-MS) is a powerful analytic technique with a very high sensitivity and specificity.Objectives
The aim of the present study is to measure concentrations of 20 bile acids using the novel Kit from Biocrates Life Sciences based on LC-MS technique.Methods
Twenty bile acid metabolites were quantitatively measured in plasma of 30 cognitively healthy subjects, 20 patients with mild cognitive impairment (MCI) and 30 patients suffering from AD.Results
Levels of lithocholic acid were significantly enhanced in plasma of AD patients (50?±?6 nM, p?=?0.004) compared to healthy controls (32?±?3 nM). Lithocholic acid plasma levels of MCI patients (41?±?4 nM) were not significantly different from healthy subjects or AD patients. Levels of glycochenodeoxycholic acid, glycodeoxycholic acid and glycolithocholic acid were significantly higher in AD patients compared to MCI patients (p?<?0.05). All other cholic acid metabolites were not significantly different between healthy subjects, MCI patients and AD patients. ROC analysis shows an overall accuracy of about 66%. Discriminant analysis was used to classify patients and we found that 15/23 were correctly diagnosed. We further showed that LCA levels increased by about 3.2 fold when healthy subjects converted to AD patients within a 8–9 year follow up period. Pathway analysis linked these changes to a putative toxic cholesterol pathway.Conclusion
In conclusion, 4 bile acids may be useful to diagnose AD in plasma samples despite limitations in diagnostic accuracy.950.
Claudia Pogoreutz Nils Rädecker Anny Cárdenas Astrid Gärdes Christian R. Voolstra Christian Wild 《Global Change Biology》2017,23(9):3838-3848
The disruption of the coral–algae symbiosis (coral bleaching) due to rising sea surface temperatures has become an unprecedented global threat to coral reefs. Despite decades of research, our ability to manage mass bleaching events remains hampered by an incomplete mechanistic understanding of the processes involved. In this study, we induced a coral bleaching phenotype in the absence of heat and light stress by adding sugars. The sugar addition resulted in coral symbiotic breakdown accompanied by a fourfold increase of coral‐associated microbial nitrogen fixation. Concomitantly, increased N:P ratios by the coral host and algal symbionts suggest excess availability of nitrogen and a disruption of the nitrogen limitation within the coral holobiont. As nitrogen fixation is similarly stimulated in ocean warming scenarios, here we propose a refined coral bleaching model integrating the cascading effects of stimulated microbial nitrogen fixation. This model highlights the putative role of nitrogen‐fixing microbes in coral holobiont functioning and breakdown. 相似文献