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991.
992.
993.
Orphan nuclear receptor LRH-1 is required to maintain Oct4 expression at the epiblast stage of embryonic development 总被引:11,自引:0,他引:11
Gu P Goodwin B Chung AC Xu X Wheeler DA Price RR Galardi C Peng L Latour AM Koller BH Gossen J Kliewer SA Cooney AJ 《Molecular and cellular biology》2005,25(9):3492-3505
Oct4 plays an essential role in maintaining the inner cell mass and pluripotence of embryonic stem (ES) cells. The expression of Oct4 is regulated by the proximal enhancer and promoter in the epiblast and by the distal enhancer and promoter at all other stages in the pluripotent cell lineage. Here we report that the orphan nuclear receptor LRH-1, which is expressed in undifferentiated ES cells, can bind to SF-1 response elements in the proximal promoter and proximal enhancer of the Oct4 gene and activate Oct4 reporter gene expression. LRH-1 is colocalized with Oct4 in the inner cell mass and the epiblast of embryos at early developmental stages. Disruption of the LRH-1 gene results in loss of Oct4 expression at the epiblast stage and early embryonic death. Using LRH-1(-/-) ES cells, we also show that LRH-1 is required to maintain Oct4 expression at early differentiation time points. In vitro and in vivo results show that LRH-1 plays an essential role in the maintenance of Oct4 expression in ES cells at the epiblast stage of embryonic development, thereby maintaining pluripotence at this crucial developmental stage prior to segregation of the primordial germ cell lineage at gastrulation. 相似文献
994.
Molecular cloning and characterization of AAAS-V2, a novel splice variant of human AAAS 总被引:4,自引:0,他引:4
Li X Ji C Gu J Xu J Jin Z Sun L Zou X Lin Y Sun R Wang P Gu S Mao Y 《Molecular biology reports》2005,32(2):127-131
Triple-A syndrome (MIM 231550; also known as Allgrove syndrome) is an autosomal recessive disorder characterized by adrenocorticotropin hormone (ACTH)-resistant adrenal insufficiency, achalasia of the oesophageal cardia and alacrima. Much initial molecular analysis supported that Triple-A syndrome was caused by mutations in AAAS, a WD-repeat protein gene. Here we report cloning and characterization of a novel splice variant of human AAAS, which we named AAAS-v2, which is located on the human chromosome 12p13. The cDNA is 1703bp, encoding a 513-amino acid polypeptide, which contains three WD40 domains, one less than the original which we called AAAS-v1 (Gen Bank: NM_015665.3). RT-PCR analysis in our work revealed that AAAS-v2 and AAAS-v1 were ubiquitously detected in human multiple tissue cDNA (MTC) panels (CLONTECH).The nucleotide sequence reported in this paper has been submitted to GenBank under accession number AY237818.Xin Li: These two authors contributed equally to this paper.Chaoneng Ji: These two authors contributed equally to this paper. 相似文献
995.
In this study, we calculated the codon usage bias in H5N1 virus and performed a comparative analysis of synonymous codon usage patterns in H5N1 virus, five other evolutionary related influenza A viruses and a influenza B virus. Codon usage bias in H5N1 genome is a little slight, which is mainly determined by the base compositions on the third codon position. By comparing synonymous codon usage patterns in different viruses, we observed that the codon usage pattern of H5N1 virus is similar with other influenza A viruses, but not influenza B virus, and the synonymous codon usage in influenza A virus genes is phylogenetically conservative, but not strain-specific. Synonymous codon usage in genes encoded by different influenza A viruses is genus conservative. Compositional constraints could explain most of the variation of synonymous codon usage among these virus genes, while gene function is also correlated to synonymous codon usages to a certain extent. However, translational selection and gene length have no effect on the variations of synonymous codon usage in these virus genes. 相似文献
996.
Simultaneous Monitoring of Phosphine and of Phosphorus Species in Taihu Lake Sediments and Phosphine Emission from Lake Sediments 总被引:4,自引:0,他引:4
Jinju?GengEmail author Xiaojun?Niu Xiangcan?Jin Xiaorong?Wang Xiaohong?Gu Marc?Edwards Dietmar?Glindemann 《Biogeochemistry》2005,76(2):283-298
Phosphine (PH3) was monitored in the Taihu Lake in China by a GC/NPD method, coupled with cryo-trapping enrichment technology. Results showed
that PH3 was universally detected in sediments, lake water and atmosphere of the Taihu Lake area. Total phosphorus (TPs) and fractions of different phosphorus species in lake sediments were separately measured as dissolved phosphate (DP), phosphorus
bound to aluminum (Al-P), iron (Fe-P) and calcium (Ca-P), occluded phosphorus (OP), and organic phosphorus (Org-P) by sequential
chemical extraction. High PH3 levels were correlated with high TPs values in sediments and with eutrophication at different sites. In addition, a positive linear correlation equation was obtained
between the concentrations of PH3 in lake sediments and of the phosphorus fractions. The resulting multiple linear regression equation is PH3 = −165 + 63.3 DP + 0.736 Al-P + 2.33 Ca-P + 2.29 Org-P. The flux of PH3 across the sediment–water interface was estimated from sediment core incubation in May and October 2002. The annual average
sediment–water flux of PH3 was estimated at ca. 0.0138±0.005 pg dm−2 h−1, the average yearly emission value of PH3 from Taihu Lake sediments to water was calculated to be 28.3±10.2 g year−1, which causes a water PH3 concentration of up to 0.178±0.064 pmol dm−3. The real importance of PH3 could be higher, because PH3 could be consumed in the oxic sediment–water boundary layer and in the water column. Spatial and temporal distributions of
total phosphorus (TPw) and chlorophyll a (Chl-a) in the water column of Taihu Lake were measured over the study period. Higher water PH3 has also been found where the TPw content was high. Similarly, high Chl-a was consistent with higher water PH3. Positive relationships between PH3 and TPw (average R2 = 0.47±0.26) and Chl-a (average R2 = 0.23±0.31) were observed in Taihu Lake water. 相似文献
997.
Beaumont C Roussot O Feve K Vignoles F Leroux S Pitel F Faure JM Mills AD Guémené D Sellier N Mignon-Grasteau S Le Roy P Vignal A 《Animal genetics》2005,36(5):401-407
A quantitative trait loci (QTL) study was undertaken to identify genome regions involved in the control of fearfulness in Japanese quail (Coturnix japonica). An F2 cross was made between two quail lines divergently selected over 29 generations on duration of tonic immobility (DTI), a catatonic-like state of reduced responsiveness to a stressful stimulation. A total of 1065 animals were measured for the logarithm of DTI (LOGTI), the number of inductions (NI) necessary to induce the immobility reaction, open-field behaviour including locomotor activity (MOVE), latency before first movement (LAT), number of jumps (JUMP), dejections (DEJ) and shouts (SHOUT), corticosterone level after a contention stress (LOGCORT) and body weight at 2 weeks of age (BW2). A total of 310 animals were included in a genome scan using selective genotyping with 248 AFLP markers. A total of 21 suggestive or genome-wide significant QTL were observed. Two highly significant QTL were identified on linkage group 1 (GL1), one for LOGTI and one for NI. In the vicinity of the QTL for LOGTI, a nearly significant QTL for SHOUT and a suggestive QTL for LAT were also identified. On GL3, genome-wide significant QTL were observed for JUMP and DEJ as well as suggestive QTL for LOGTI, MOVE, SHOUT and LAT. A significant QTL for BW2 was observed on GL2 and a nearly significant one on GL1. These results may be useful in the understanding of fearfulness in quail and related species provided that fearfulness has the same genetic basis. 相似文献
998.
Coppin A Varré JS Lienard L Dauvillée D Guérardel Y Soyer-Gobillard MO Buléon A Ball S Tomavo S 《Journal of molecular evolution》2005,60(2):257-267
Single-celled apicomplexan parasites are known to cause major diseases in humans and animals including malaria, toxoplasmosis, and coccidiosis. The presence of apicoplasts with the remnant of a plastid-like DNA argues that these parasites evolved from photosynthetic ancestors possibly related to the dinoflagellates. Toxoplasma gondii displays amylopectin-like polymers within the cytoplasm of the dormant brain cysts. Here we report a detailed structural and comparative analysis of the Toxoplasma gondii, green alga Chlamydomonas reinhardtii, and dinoflagellate Crypthecodinium cohnii storage polysaccharides. We show Toxoplasma gondii amylopectin to be similar to the semicrystalline floridean starch accumulated by red algae. Unlike green plants or algae, the nuclear DNA sequences as well as biochemical and phylogenetic analysis argue that the Toxoplasma gondii amylopectin pathway has evolved from a totally different UDP-glucose-based metabolism similar to that of the floridean starch accumulating red alga Cyanidioschyzon merolae and, to a lesser extent, to those of glycogen storing animals or fungi. In both red algae and apicomplexan parasites, isoamylase and glucan–water dikinase sequences are proposed to explain the appearance of semicrystalline starch-like polymers. Our results have built a case for the separate evolution of semicrystalline storage polysaccharides upon acquisition of photosynthesis in eukaryotes.This article contains online-only supplementary material.Reviewing Editor:Dr. Patrick Keeling 相似文献
999.
Previously, we reported that Phe105 in transmembrane domain 2 of the mouse dopamine transporter (DAT) is crucial for high-affinity cocaine binding. In the current study, we investigated whether other residues surrounding Phe105 also affect the potency of cocaine inhibition. After three rounds of sequential random mutagenesis at these residues, we found a triple mutant (L104V, F105C and A109V) of mouse DAT that retained over 50% uptake activity and was 69-fold less sensitive to cocaine inhibition when compared with the wild-type mouse DAT. The triple mutation also resulted in a 47-fold decrease in sensitivity to methylphenidate inhibition, suggesting that the binding sites for cocaine and methylphenidate may overlap. In contrast, the inhibition of dopamine uptake by amphetamine or methamphetamine was not significantly changed by the mutations, suggesting that the binding sites for the amphetamines differ from those for cocaine and methylphenidate. Such functional but cocaine-insensitive DAT mutants can be used to generate a knock-in mouse line to study the role of DAT in cocaine addiction. 相似文献
1000.
Ji Q Lu J Chao Q Gu M Xu M 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(8):1495-1503
Wide-compatibility (WC) is one of the most important traits in rice, which can overcome the fertility barrier in the indica/japonica hybrids, and hence to make it possible to utilize the higher yield potential of inter-subspecific hybrids. The S
5
n
gene located on chromosome 6 has been previously reported to be responsible for the wide-compatibility in rice. Here we report
the precise location of the S
5
n
gene. In the first-pass mapping, the S
5
n
gene was restricted within a 200 kb region by using a population of 242 isogenic lines in combination with high-density markers
developed in the S
5 region. In the fine mapping, the S
5 region was further saturated with newly developed markers and more isogenic lines (549 in total) were investigated. Eventually,
the S
5
n
gene was mapped within a 50 kb region delimited by the left marker J13 and the right marker J17. One BAC clone screened from
the BAC library of the WC rice variety 02428 covered the whole S
5 region. Sequence analysis of the 50 kb region revealed two candidate genes, coding an aspartyl protease and a hypothetical
protein. This result would greatly accelerate both cloning and marker-assisted selection of this important S
5
n
gene.
Qing Ji and Jufei Lu have contributed equally to this paper. 相似文献