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In this paper we give a parallel algorithm for constructing the Voronoi diagram of a polygonal scene, i.e., a set of line segments in the plane such that no two segments intersect except possibly at their endpoints. Our algorithm runs inO(log2
n) time usingO(n) processors in the CREW PRAM model.The research of M. T. Goodrich was supported by NSF under Grants CCR-8810568 and CCR-9003299 and by NSF/DARPA under Grant CCR-8908092. C. K. Yap's research was supported in part by NSF Grants DCR-8401898 and CCR-9002819. 相似文献
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S Morán MJ Irarrázaval R Zalaquett M Villavicencio B Garayar C Mu?oz G Maturana J Urzúa G Lema 《Canadian Metallurgical Quarterly》1997,125(4):391-401
The manufacturing process for albumin in Australia is based primarily on ion-exchange chromatography. The capacity of ion-exchange matrices to remove non-enveloped viruses (canine parvovirus and poliovirus type 1) was assessed using a scaled-down chromatographic process which was shown to yield product meeting purity criteria set for the manufacturing process. Poliovirus type 1 and canine parvovirus were added at one tenth the volume of desalted and delipidated Supernatant II + III produced by traditional Cohn Fractionation from human plasma before the material was applied to DEAE and CM ion-exchangers connected in series. Samples were taken at equilibration, wash, elution and regeneration steps and the log clearance and reduction of the viruses calculated. The mean clearance and reduction factors for viral load of poliovirus type 1 were 5.3 logs and 3.2 logs, respectively and 1.8 logs and 1.8 logs for canine parvovirus. 相似文献
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Recent studies indicate that Caenorhabditis elegans CED-4 interacts with and promotes the activation of the death protease CED-3, and that this activation is inhibited by CED-9. Here we show that a mammalian homolog of CED-4, Apaf-1, can associate with several death proteases, including caspase-4, caspase-8, caspase-9, and nematode CED-3 in mammalian cells. The interaction with caspase-9 was mediated by the N-terminal CED-4-like domain of Apaf-1. Expression of Apaf-1 enhanced the killing activity of caspase-9 that required the CED-4-like domain of Apaf-1. Furthermore, Apaf-1 promoted the processing and activation of caspase-9 in vivo. Bcl-XL, an antiapoptotic member of the Bcl-2 family, was shown to physically interact with Apaf-1 and caspase-9 in mammalian cells. The association of Apaf-1 with Bcl-XL was mediated through both its CED-4-like domain and the C-terminal domain containing WD-40 repeats. Expression of Bcl-XL inhibited the association of Apaf-1 with caspase-9 in mammalian cells. Significantly, recombinant Bcl-XL purified from Escherichia coli or insect cells inhibited Apaf-1-dependent processing of caspase-9. Furthermore, Bcl-XL failed to inhibit caspase-9 processing mediated by a constitutively active Apaf-1 mutant, suggesting that Bcl-XL regulates caspase-9 through Apaf-1. These experiments demonstrate that Bcl-XL associates with caspase-9 and Apaf-1, and show that Bcl-XL inhibits the maturation of caspase-9 mediated by Apaf-1, a process that is evolutionarily conserved from nematodes to humans. 相似文献
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F Hidalgo Pardo A Conte Visús M Rebassa Llull P Losada González C Gutiérrez Sanz-Gadea M Ozonas Moragues 《Canadian Metallurgical Quarterly》1998,22(4):366-368
Acute myocardial infarction developed in a 14-year-old girl, ten years after surgical repair of a coronary artery fistula. Angiography revealed fresh thrombus in the left anterior descending branch of the left coronary artery. The thrombus probably developed in the residual cul-de-sac of the occluded fistula. A procedure to abolish the cul-de-sac was then performed. 相似文献
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K Stefíková V Spustová K Gazdíková Z Krivosíková R Dzúrik 《Canadian Metallurgical Quarterly》1997,29(4):497-507
Insulin resistance (IR) and secondary hyperinsulinaemia are major risk factors of atherosclerosis and probably also of related glomerulosclerosis. Angiotensin converting enzyme inhibitors (ACEI), while improving IR in essential hypertension, do not improve it in patients with chronic renal disease. Thus, the combination of ACEI and low protein diet was evaluated. Thirty-eight patients with various kidney diseases and mild to moderate impairment of kidney function were included in the study. Thirteen of them suffered from IR. Their dietary protein intake was decreased from > or = 1.0 g/kg/d to 0.6-0.7 g/kg/d. Moreover, they were treated by ACEI enalapril at dosages of 2-10 mg/d depending on the absence/presence and severity of hypertension. The patients were followed for 8 months. No clinically relevant kidney disease progression (KDP) was found. IR patients improved remarkably. IR was examined by the oral glucose tolerance test and glucose, insulin and C-peptide determinations. Their increased plasma triglyceride, VLDL concentrations and proteinuria decreased, HDL concentration increased. Acid-base balance and anaemia did not change. It is concluded that protein restriction in combination with ACEI treatment improve IR and the associated dyslipoproteinaemia and proteinuria. 相似文献