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991.
992.
Aster Gebrekirstos Meine van Noordwijk Henry Neufeldt Ralph Mitl?hner 《Trees - Structure and Function》2011,25(1):95-102
The relationships between annual wood stable carbon isotope composition (δ13C), dry season midday plant water potential, and annual growth rate were investigated to asses the ability of agroforestry
species to adapt to climate changes. 6–8 stem disks from four co-occurring species (Acacia senegal, A. seyal, A. tortilis and Balanites aegyptiaca) were collected for radial growth measurements using tree-ring analysis spanning 1930–2003. Annual δ13C was measured on three tree disks per species for the period 1970–2002. Midday plant water potential was measured during
the dry season. Annual radial growth and midday plant water potential ranged from 0.27 to 9.12 mm and −1.0 to −5.0 MPa, respectively,
with statistically significant differences. After correcting annual wood δ13C for atmospheric changes in δ13C, carbon isotopic composition ranged from −22.22 to −26.58‰. Relationships between δ13C, radial growth and plant water potentials revealed the interaction of water availability, stomatal conductance, δ13C values and growth. Two contrasting water use strategies and competitive advantages can be distinguished. Species with lower
mean δ13C values (A. senegal and A. seyal) show high plant water potential and, hence, better growth during moist years. Thus, they indicate low water use efficiency
(WUE) and opportunistic water use strategy. On the other hand, species with lower water potentials (A. tortilis and B. aegyptiaca) showed relative better growth performance and less increase in δ13C in drought years, reflecting their high WUE and conservative water use strategy. These results suggest that δ13C in tree rings can be useful in estimating historic changes in plant WUE and hence in screening drought tolerant species
in the face of expected climate changes, as well as for assessing the functional diversity and risk reduction in mixed vegetation. 相似文献
993.
While our understanding of gene-based biology has greatly improved, it is clear that the function of the genome and most diseases cannot be fully explained by genes and other regulatory elements. Genes and the genome represent distinct levels of genetic organization with their own coding systems; Genes code parts like protein and RNA, but the genome codes the structure of genetic networks, which are defined by the whole set of genes, chromosomes and their topological interactions within a cell. Accordingly, the genetic code of DNA offers limited understanding of genome functions. In this perspective, we introduce the genome theory which calls for the departure of gene-centric genomic research. To make this transition for the next phase of genomic research, it is essential to acknowledge the importance of new genome-based biological concepts and to establish new technology platforms to decode the genome beyond sequencing. 相似文献
994.
995.
996.
Ruiz JF Kedziora K Keogh B Maguire J Reilly M Windle H Kelleher DP Gilmer JF 《Bioorganic & medicinal chemistry letters》2011,21(22):6636-6640
The design, synthesis and delivery potential of a new type of benzenesulfonamide cyclo-oxygenase-2 (COX-2) inhibitor prodrug is investigated using celecoxib. The approach involves a double prodrug that is activated first by azoreductases and then by cyclization triggering drug release. We studied the intramolecular aminolysis of the acylsulfonamide. The cyclization was surprisingly rapid at physiological pH and very fast at pH 5. The prodrug is activated specifically under conditions found in the colon but highly stable in the presence of human and rodent intestinal extracts. Finally, the prototype with celecoxib was transported much more slowly in the Caco-2 transepithelial model than the parent. The design therefore shows significant promise for the site specific delivery of benzenesulfonamide COX-2 inhibitors to the colon. 相似文献
997.
De Savi C Pape A Sawyer Y Milne D Davies C Cumming JG Ting A Lamont S Smith PD Tart J Page K Moore P 《Bioorganic & medicinal chemistry letters》2011,21(11):3301-3306
A new achiral class of N-hydroxyformamide inhibitor of both ADAM-TS4 and ADAM-TS5, 2 has been discovered through modification of the complex P1 group present in historical inhibitors 1. This structural change improved the DMPK properties and greatly simplified the synthesis whilst maintaining excellent cross-MMP selectivity profiles. Investigation of structure-activity and structure-property relationships in the P1 group resulted in both ADAM-TS4 selective and mixed ADAM-TS4/5 inhibitors. This led to the identification of a pre-clinical candidate with excellent bioavailability across three species and predicting once daily dosing kinetics. 相似文献
998.
Xiao D Palani A Sofolarides M Huang Y Aslanian R Vaccaro H Hong L McKittrick B West RE Williams SM Wu RL Hwa J Sondey C Lachowicz J 《Bioorganic & medicinal chemistry letters》2011,21(2):861-864
A series of 2-piperidinopiperidine-5-arylthiadiazoles was synthesized and subjected to a structure-activity relationship (SAR) investigation. The potency of this series was improved to the single digit nanomolar range. The key analogs were shown to be free of P450 issues, and they also maintained good ex vivo activity and brain penetration. 相似文献
999.
Maintaining cell volume is critical for cellular function yet shift in cell volume is a prerequisite for mitosis and apoptosis. The ubiquitously and evolutionary conserved serine/threonine kinase CK2 promotes cell survival and suppresses apoptosis. The present review describes how mammalian cells regulate the cellular content of the major cellular organic osmolyte, taurine with emphasis on CK2 mediated regulation of active taurine uptake and volume-sensitive taurine release. Furthermore, we discuss how CK2-mediated regulation of taurine homeostasis is potentially involved in cellular functions such as proliferation and survival. 相似文献
1000.
High-throughput sequencing of pooled DNA was applied to polymorphism discovery in candidate genes involved in starch synthesis. This approach employed semi- to long-range PCR (LR-PCR) followed by next-generation sequencing technology. A total of 17 rice starch synthesis genes encoding seven classes of enzymes, including ADP-glucose pyrophosphorylase (AGPase), granule starch synthase (GBSS), soluble starch synthase (SS), starch branching enzyme (BE), starch debranching enzyme (DBE) and starch phosphorylase (SPHOL) and phosphate translocator (GPT1) from 233 genotypes were PCR amplified using semi- to long-range PCR. The amplification products were equimolarly pooled and sequenced using massively parallel sequencing technology (MPS). By detecting single nucleotide polymorphism (SNP)/Indels in both coding and noncoding areas of the genes, we identified genetic differences and characterized the SNP/Indel variation and distribution patterns among individual starch candidate genes. Approximately, 60.9 million reads were generated, of which 54.8 million (90%) mapped to the reference sequences. The average coverage rate ranged from 12,708 to 38,300 times for SSIIa and SSIIIb, respectively. SNPs and single/multiple-base Indels were analysed in a total assembled length of 116,403 bp. In total, 501 SNPs and 113 Indels were detected across the 17 starch-related loci. The ratio of synonymous to nonsynonymous SNPs (Ka/Ks) test indicated GBSSI and isoamylase 1 (ISA1) as the least diversified (most purified) and conservative genes as the studied populations have been through cycles of selection. This report demonstrates a useful strategy for screening germplasm by MPS to discover variants in a specific target group of genes. 相似文献