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排序方式: 共有467条查询结果,搜索用时 343 毫秒
61.
62.
Thomas J. Manning Katie Olsen Lori Hardin Jerry Purcell Timothy M. Ayers Michael A. Duncan 《臭氧:科学与工程》2006,28(3):177-180
The impact of the oxidizing agent ozone (O3) on the structure of the most common spherical allotrope of carbon, buckminsterfullerene (C60) is studied. Past studies measured ozonation of C60 over short periods of time. In this study, we establish that C60 is completely degraded, not polymerized, during ozonation. The techniques, laser desorption time-of-flight mass spectrometry, UV/Vis absorbance spectroscopy, and FT-Raman are used to study the molecular degradation of the spherical allotrope C60 by O3. 相似文献
63.
Larry W. Daniel Lori A. Etkin Bennett T. Morrison Judy Parker Susan Morris-Natschke Jefferson R. Surles Claude Plantadosi 《Lipids》1987,22(11):851-855
Recent studies have shown that the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) stimulates protein kinase C (PKC), whereas the ether-linked phospholipid 1-O-octadecyl-2-O-methyl-rac-glycerol-3-phosphocholine (ET-18-OCH3) inhibits PKC activity in vitro. Therefore, the antitumor effects of ET-18-OCH3 could be due to its inhibition of PKC activity and the effects of tumor promotion. TPA stimulates arachidonic acid release, prostaglandin synthesis, phosphatidylcholine synthesis and the degradation of phosphatidylcholine by phospholipase C in Madin Darby canine kidney (MDCK) cells. Therefore, we have determined the effects of ET-18-OCH3 on these consequences of TPA stimulation. Preliminary experiments determined that ET-18-OCH3 inhibited PKC partially purified from MDCK cells by ion-exchange chromatography on DEAE-cellulose. In addition, ET-18-OCH3, inhibited the TPA-stimulated phosphorylation of a 40,000-dalton protein in intact MDCK cells. These data indicate that ET-18-OCH3 is an effective inhibitor of PKC activity in MDCK cells. In addition, ET-18-OCH3 was found to inhibit arachidonic acid release and prostaglandin synthesis. The inhibition of prostaglandin synthesis appears to be secondary to inhibition of arachidonic acid release, since ET-18-OCH3 does not inhibit TPA-stimulated synthesis of prostaglandin H synthase or the activity of the enzyme directly (Parker, J., Daniel, L. W., and Waite, M. [1987]J. Biol. Chem. 262, 5385–5393). ET-18-OCH3 also inhibits TPA-stimulated phosphatidylcholine synthesis and phosphatidylcholine degradation by phospholipase C. These data provide evidence that the antineoplastic ether lipids inhibit the biochemical effects of the tumor promoter TPA in intact cells and indicate that this inhibition may have a role in their biological activities. 相似文献
64.
65.
Lacson E Teng M Ong J Vienneau L Ofsthun N Lazarus JM 《Hemodialysis international. International Symposium on Home Hemodialysis》2005,9(4):367-375
Recombivax-HB (REC) and Engerix-B (ENG) are FDA-approved vaccines for hepatitis B virus (HBV) in end-stage renal disease (ESRD). This study compares antibody response rates between them in routine clinical practice. Patients completing the recommended 40 mug dose of REC (3 doses) or ENG (4 doses) between January 1, 2000 to April 30, 2003 were eligible. Patients with prior positive HBV surface antigen (HBsAg) or antibody (HBsAb) test results were excluded. The conversion rate and persistence of protective titer (HBsAb titer>or=10 IU/mL) were tracked for 1 year. A supplemental analysis of a one-to-one matched patient sample was also performed. REC patients (N=885) were older, had longer dialysis vintage, and had a larger proportion of whites than ENG patients (N=13,661). Cumulative conversion response was greater in ENG (58%) than REC (40%) at 1 year (p<0.0001). The odds ratio for response to ENG compared with REC was 1.96 (95% limits: 1.56, 2.45; p<0.0001) adjusted for age, gender, race, diabetes, vintage, BSA, hemoglobin, and eKt/V. Persistent protective HBsAb after 1 year was 77% (ENG) vs. 53% (REC). HBsAg was positive in 208 ENG patients (1.5%) with all but 1 because of transient, vaccine-related antigenemia. The difference in conversion response favoring ENG persisted in a one-to-one sample matched for age, gender, race, modality, and dialysis vintage. The study found higher seroconversion response to ENG compared with REC at several time points up to 1 year. Protective HBsAb disappeared in 23-47% of patients 1 year later, validating CDC recommendations to re-test HBsAb yearly. The observed difference in response rates may be related to the extra ENG dose given at the second month (0, 1, 2, 6 regimen). The study raises a hypothesis that requires confirmation in a prospective clinical trial. 相似文献
66.
Iacono William G.; Peloquin Lori Jeanne; Lumry Ann E.; Valentine Roger H.; Tuason Vincente B. 《Canadian Metallurgical Quarterly》1982,91(1):35
Examined patients (20–66 yrs old) with a history of recurrent affective disorder on a variety of smooth-pursuit and saccadic eye-tracking tasks and on psychomotor analogs of these tasks. The 25 unipolar and 24 bipolar Ss were compared to 24 schizophrenics; all Ss were in remission. Results indicate that the performance of the 2 affective-disorder groups was not significantly different from that of the controls on any of these tasks. Smooth-pursuit tracking error was greater for Ss receiving Li and for those with a higher frequency of prior episodes of the disorder. When the pursuit eye movements of these Ss were compared to those of the schizophrenics, the latter produced more tracking error than both affective-disorder groups but significantly so only with respect to unipolar Ss. Although findings are consistent with the interpretation that tracking dysfunction is not a trait characteristic of affective disorders, further investigations contrasting remitted patients with bipolar and schizophrenic disorders are needed to determine the specificity of deviant tracking to schizophrenia. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
67.
Methyl eugenol (ME) is a natural phenylpropanoid highly attractive to oriental fruit fly Bactrocera dorsalis (Hendel) males. The flies eagerly feed on ME and produce hydroxylated metabolites with both pheromonal and allomonal functions. Side-chain metabolic activation of ME has long been recognized as a primary reason for hepatocarcinogenicity of this compound on rodents. In an attempt to develop a safer alternative to ME for fruit fly management, we developed a fluorine analog 1,2-dimethoxy-4-(3-fluoro-2-propenyl)benzene (I), which, in earlier field tests, was as active to the oriental fruit fly as ME. Now we report that B. dorsalis males are not only attracted to, but also eagerly consume (up to ∼1 mg/insect) compound I, thus recognizing this fluorinated benzene as a close kin of the natural ME. The flies metabolized the fluorine analog I in a similar fashion producing mostly two hydroxylated products, 2-(3-fluoro-2-propenyl)-4,5-dimethoxyphenol (II) and (E)-coniferyl alcohol (III), which they stored in rectal glands. However, the introduction of the fluorine atom at the terminal carbon atom of the double bond favors the ring hydroxylation over a side-chain metabolic oxidation pathway, by which coniferyl alcohol is produced. It also appears that fluorination overall impedes the metabolism: at high feed rate (10 μl per 10 males), the flies consumed in total more fluorine analog I than ME but were unable to metabolize it as efficiently as ME. 相似文献
68.
Ashot Khrimian Matthew S. Siderhurst Grant T. Mcquate Nicanor J. Liquido Janice Nagata Lori Carvalho Filadelfo Guzman Eric B. Jang 《Journal of chemical ecology》2009,35(2):209-218
Oriental fruit fly, Bactrocera dorsalis (Hendel), males are highly attracted to the natural phenylpropanoid methyl eugenol (ME). They compulsively feed on ME and
metabolize it to ring and side-chain hydroxylated compounds that have both pheromonal and allomonal functions. Side-chain
metabolic activation of ME leading to (E)-coniferyl alcohol has long been recognized as a primary reason for hepatocarcinogenicity of this compound in rodents. Earlier,
we demonstrated that introduction of a fluorine atom at the terminal carbon of the ME side chain significantly depressed metabolism
and specifically reduced formation of coniferyl alcohol but had little effect on field attractiveness to B. dorsalis. In the current paper, we demonstrate that fluorination of ME at the 4 position of the aromatic ring blocks metabolic ring-hydroxylation
but overall enhances side-chain metabolism by increasing production of fluorinated (E)-coniferyl alcohol. In laboratory experiments, oriental fruit fly males were attracted to and readily consumed 1,2-dimethoxy-4-fluoro-5-(2-propenyl)benzene
(I) at rates similar to ME but metabolized it faster. Flies that consumed the fluorine analog were as healthy post feeding
as ones fed on methyl eugenol. In field trials, the fluorine analog I was ∼50% less attractive to male B. dorsalis than ME.
相似文献
Ashot KhrimianEmail: |
69.
Benoit Carbain Patrick J. Collins Dr. Lori Callum Stephen R. Martin Dr. Alan J. Hay Dr. John McCauley Dr. Hansjörg Streicher Dr. 《ChemMedChem》2009,4(3):335-337
With a Hunsdiecker–Barton iododecarboxylation strategy, we converted the carboxylate group of the oseltamivir precursor into exemplary phosphonate monoesters. In all cases, Ki values towards influenza virus sialidase remained in the sub‐nanomolar range. We have thus made valuable structural space available for the design of novel oseltamivir‐based tools for influenza virus research.
70.