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941.
Three antibiotics were evaluated for their effects on the elimination of Agrobacterium tumefaciens during the genetic transformation of loblolly pine ( Pinus taeda L.) using mature zygotic embryos as targets. Agrobacterium tumefaciens strains, EHA105, GV3101, and LBA 4404, all harbouring the plasmid pCAMBIA1301, which carries the selectable marker gene, hygromycin phosphotransferase ( hpt) controlled by the cauliflower mosaic virus 35S promoter and terminator, and the uidA reporter gene (GUS) driven by the cauliflower mosaic virus 35S promoter and the terminator of nopaline synthase gene, were used in this study. Exposure to 350 mg l-1 carbenicillin, claforan, and timentin respectively for up to 6 weeks did not eliminate the Agrobacterium, while antibiotics at 500 mg l-1 eradicated them from the co-cultivated zygotic embryos. All three antibiotics increased callus growth and shoot regeneration at 350 and 500 mg l-1 each, but reduced callus growth and shoot regeneration at 650 mg l-1 when compared with controls. Putative transgenic calli were selected for continued proliferation and differentiation on 4.5 mg l-1 hygromycin-containing medium. Transformed calli and transgenic plants produced on a selection medium containing 4.5 mg l-1 hygromycin were confirmed by GUS histochemical assays, by polymerase chain reaction (PCR), and by Southern blot analysis. These results are useful for future studies on optimizing genetic transformation procedures in loblolly pine. 相似文献
942.
943.
Luo D Rogers CN Steed JT Gilliam LK Hampe CS Lernmark A 《Journal of biotechnology》2004,111(1):97-104
We evaluated a biotin-glutamic acid decarboxylase 65 (GAD65)-based enzyme-linked immunosorbent assay (B-ELISA) to detect GAD65 autoantibodies (GAD65Ab) in 78 sera from individuals with newly diagnosed type 1 diabetes. The GAD65Ab index of patients with type 1 diabetes (mean value of GAD65Ab index of 1.891) was significantly higher than those in 50 sera from healthy control group (mean value of 0.068). The intra- and inter-assay coefficients of variation (CV) were calculated to be 1.042 and 10.703%, respectively. The specificity of the B-GAD65 ELISA was comparable to the standard radioimmunoassay (RIA) which is routinely used in the laboratory. We describe the optimal conditions of the binding kinetics from each assay-step for the detection of GAD65Ab using the WHO standard serum 97/550 as a model autoantibody serum. We concluded that incubation times of 15, 90, and 90 min for step 1 (pre-incubation of Biotin14-GAD65 with serum), step 2 (binding the Ab/Ag complex to NeutrAvidin plate), and step 3 (incubation with HRPO-anti-human IgG), respectively, along with human serum dilutions of 1:50, would provide an optimal assay signal within a relatively short timeframe. 相似文献
944.
Li Q Manolescu A Ritzel M Yao S Slugoski M Young JD Chen XZ Cheeseman CI 《American journal of physiology. Gastrointestinal and liver physiology》2004,287(1):G236-G242
Facilitated glucose transporters (GLUTs) mediate transport of sugars across cell membranes by using the chemical gradient of sugars as the driving force. Improved cloning techniques and database analyses have expanded this family of proteins to a total of 14 putative members. In this work a novel hexose transporter isoform, GLUT7, has been cloned from a human intestinal cDNA library by using a PCR-based strategy (GenBank accession no. AY571960). The encoded protein is comprised of 524 amino acid residues and shares 68% similarity and 53% identity with GLUT5, its most closely related isoform. When GLUT7 was expressed in Xenopus oocytes, it showed high-affinity transport for glucose (K(m) = 0.3 mM) and fructose (IC(50) = 0.060 mM). Galactose, 2-deoxy-d-glucose, and xylose were not transported. Uptake of 100 microM d-glucose was not inhibited by 200 microM phloretin or 100 microM cytochalasin B. Northern blotting indicated that the mRNA for GLUT7 is present in the human small intestine, colon, testis, and prostate. Western blotting and immunohistochemistry of rat tissues with an antibody raised against the predicted COOH-terminal sequence confirmed expression of the protein in the small intestine and indicated that the transporter is predominantly expressed in the enterocytes' brush-border membrane. The unusual substrate specificity and close sequence identity with GLUT5 suggest that GLUT7 represents an intermediate between class II GLUTs and the class I member GLUT2. Comparison between these proteins may provide key information as to the structural determinants for the recognition of fructose as a substrate. 相似文献
945.
Min Tong A Ya Lu W He Xu J Qiang Lin G 《Bioorganic & medicinal chemistry letters》2004,14(9):2095-2097
A facile method for enzymatic glycosylation of 4-substituted benzyl alcohols and tyrosol with glucose in a monophasic aqueous-dioxane medium was reported, using a crude meal of apple seed as a new catalyst. The corresponding beta-d-glucosides were synthesized in moderate yields (13.1-23.1%), among which the salidroside was obtained in 15.8% yield. 相似文献
946.
Tan Q Birzin ET Chan W Yang YT Pai LY Hayes EC DaSilva CA DiNinno F Rohrer SP Schaeffer JM Hammond ML 《Bioorganic & medicinal chemistry letters》2004,14(14):3753-3755
Dihydrobenzodithiin compounds (1-6) were prepared to explore the expansion of the dihydrobenzoxathiin lead compounds I-III as SERAMs (Selective Estrogen Receptor Alpha Modulators). The dihydrobenzodithiin compounds generally maintained a high degree of selectivity for ERalpha over ERbeta, however, they lacked the in vivo antagonism/agonism activity exhibited by the lead class in an immature rat uterine growth model. 相似文献
947.
The synthesis and structural analysis, involving X-ray crystallographic, nuclear magnetic resonance, and computational studies of four diastereomers of the common western BCD diarylether macrocycle of the complestatins, a family of HIV entry inhibitors, has been achieved exploiting a ruthenium-promoted intramolecular S(N)Ar reaction. The stereogenicity of the individual phenylglycines (residues C and D) results in remarkable effects on the backbone conformation. 相似文献
948.
Chen WH Chan CL Cai Z Luo GA Jiang ZH 《Bioorganic & medicinal chemistry letters》2004,14(19):4955-4959
The noncovalent complexes of four cytotoxic protoberberine alkaloids that is, berberine, palmatine, jatrorrhizine, and coptisine with double-stranded oligodeoxynucleotides d(AAGAATTCTT)(2) were investigated by electrospray ionization mass spectrometry. These four active components from Chinese herbal medicines showed both 1:1 and 1:2 binding stoichiometries, independent on the alkaloid-to-DNA ratios. Binding affinities in the order of palmatine> or =jatrorrhizine>coptisine>berberine with d(AAGAATTCTT)(2) were obtained. Additionally, the preliminary results indicated that berberine had some sequence selectivities. 相似文献
949.
Synthesis and evaluation of tacrine-E2020 hybrids as acetylcholinesterase inhibitors for the treatment of Alzheimer's disease 总被引:2,自引:0,他引:2
Tacrine-E2020 hybrids and some related compounds were prepared and their bioactivities on the Alzheimer's disease were assayed. The optimum hybrid inhibitor 3 is 37-fold more potent and 31-fold more selective than tacrine in vitro. 相似文献
950.
Plasmalemmal vacuolar-type H+-ATPase in cancer biology 总被引:6,自引:0,他引:6
Vacuolar-type H+-adenosine triphosphatase (V-ATPase) is one of the most fundamental enzymes in nature. V-ATPases are responsible for the regulation
of proton concentration in the intracellular acidic compartments. It has similar structure with the mitochondrial F0F1-ATP synthase (F-ATPase).† The V-ATPases are composed of multiple subunits and have various physiological functions, including membrane and organelle
protein sorting, neurotransmitter uptake, cellular degradative processes, and cytosolic pH regulation. The V-ATPases have
been involved in multidrug resistance. Recently, plasma membrane V-ATPases have been involved in regulation of extracellular
acidity, essential for cellular invasiveness and proliferation in tumor metastasis. The current knowledge regarding the structure
and function of V-ATPase and its role in cancer biology is discussed.
F in F0F1 ATPase is the coupling energy factor. 相似文献