全文获取类型
收费全文 | 2172篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 10篇 |
金属工艺 | 1篇 |
机械仪表 | 38篇 |
建筑科学 | 5篇 |
能源动力 | 1篇 |
轻工业 | 87篇 |
水利工程 | 1篇 |
无线电 | 5篇 |
一般工业技术 | 4篇 |
冶金工业 | 2010篇 |
自动化技术 | 7篇 |
出版年
2021年 | 2篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2013年 | 3篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 6篇 |
2009年 | 9篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 12篇 |
2005年 | 9篇 |
2004年 | 3篇 |
2003年 | 12篇 |
2002年 | 13篇 |
2001年 | 7篇 |
2000年 | 17篇 |
1999年 | 75篇 |
1998年 | 603篇 |
1997年 | 355篇 |
1996年 | 222篇 |
1995年 | 139篇 |
1994年 | 99篇 |
1993年 | 121篇 |
1992年 | 13篇 |
1991年 | 20篇 |
1990年 | 15篇 |
1989年 | 17篇 |
1988年 | 25篇 |
1987年 | 15篇 |
1986年 | 17篇 |
1985年 | 17篇 |
1984年 | 1篇 |
1983年 | 8篇 |
1982年 | 8篇 |
1981年 | 19篇 |
1980年 | 27篇 |
1978年 | 6篇 |
1977年 | 66篇 |
1976年 | 160篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1964年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有2173条查询结果,搜索用时 0 毫秒
151.
RM Zaslavskaia SI Logvinenko AG Logvinenko MM Te?blium 《Canadian Metallurgical Quarterly》1997,(2):23-27
The circadian pattern of hemocoagulation was studied in patients with decompensated rheumatic heart disease (DRHD) concurrent with stages I-II circulatory failure (CF) during complex treatment or medical treatment with disaggregants. Biorhythmological studies demonstrated that in patients with DRHD and CF chronotherapy with curantyl had some advantages over the traditional therapy during complex drug therapy. In these patients, the chronopatterns of circadian rhythms of hemocoagulative parameters tended to normalize under the influence of curantyl chronotherapy, by diminishing the signs of external desynchronization. Advantages of chronotherapy over the traditional treatment found in patients with DRHD and stages I-II CF, as manifested by its clinical effect in shorter periods (on days 4-5) when small daily and course doses of the drug were used. Based on the biorhythmological studies of hemostatic parameters, a method of curantyl chronotherapy was developed for patients with DRHD and stages I-II CF, which may optimize the therapeutical process in patients with this abnormality. 相似文献
152.
Loss of protein kinase C inhibition in the beta-T594M variant of the amiloride-sensitive Na+ channel
Y Cui YR Su M Rutkowski M Reif AG Menon RY Pun 《Canadian Metallurgical Quarterly》1997,94(18):9962-9966
We previously reported the presence of a novel variant (beta-T594M) of the amiloride-sensitive Na+ channel (ASSC) in which the threonine residue at position 594 in the beta-subunit has been replaced by a methionine residue. Electrophysiological studies of the ASSC on Epstein-Barr virus (EBV)-transformed lymphocytes carrying this variant showed that the 8-(4-chlorophenylthio) adenosine 3':5'-cyclic monophosphate (8cpt-cAMP)-induced responses were enhanced when compared to wild-type EBV-transformed lymphocytes. Furthermore, in wild-type EBV-transformed cells, the 8cpt-cAMP-induced response was totally blocked by the phorbol ester, phorbol 12-myristate 13-acetate (PMA). This inhibitory effect of PMA was blocked by a protein kinase C inhibitor, chelerythrine. We now have identified individuals who are homozygous for this variant, and showed that PMA had no effect on the 8cpt-cAMP-induced responses in the EBV-transformed lymphocytes from such individuals. Cells heterozygous for this variant showed mixed responses to PMA, with the majority of cells partially inhibited by PMA. Our results demonstrate that an alteration in a single amino acid residue in the beta-subunit of the ASSC can lead to a total loss of inhibition to PMA, and establish the beta-subunit as having an important role in conferring a regulatory effect on the ASSC of lymphocytes. 相似文献
153.
154.
155.
156.
There is a pressing need to reduce the time and cost of developing new cytotoxic agents and to accurately identify clinically active agents at an early stage. In this study, the differential staining cytotoxicity (DiSC) assay was used to assess the efficacy of the novel antitumour cAMP analogue, 8-chloro-cAMP (8-Cl-cAMP) (and its metabolite 8-Cl-adenosine) against 107 fresh specimens of human neoplastic and normal cells. Diagnoses included chronic and acute leukaemias, myeloma, non-Hodgkin's lymphoma (NHL) and miscellaneous solid tumours. The aim was to identify targets for subsequent phase I, II and III trials. 8-Cl-cAMP was tested at 4-985 microM, along with standard chemotherapeutic drugs. 8-Cl-cAMP and its metabolite caused no morphologically observable cell differentiation but induced dose-dependent cytotoxicity. Compared with untreated patients, previously treated chronic lymphocytic leukaemia (CLL) patients showed no increase in ex vivo resistance to 8-Cl-cAMP (P = 0.878); minimal cross-resistance with other cytotoxic drugs was detected. Compared with normal cells (mean LC90 = 1803 microM), 8-Cl-cAMP showed significant ex vivo activity against CLL (117.0 microM; P < 0.0001) and NHL (140.0 microM; P < 0.0001), of which eight were mantle cell NHL (84.7 microM), and greatest activity against cells from patients with acute myeloid leukaemia (AML; mean LC90 = 24.3 microM; in vitro therapeutic index 74-fold, P < 0.0001). Solid tumour specimens were comparatively resistant to 8-Cl-cAMP. The results highlight the clinical potential of 8-Cl-cAMP, point to several new phase I, II and III trial possibilities and provide a rationale for the inclusion of ex vivo cytotoxic drug evaluation in the drug development process. 相似文献
157.
158.
Porcine neuropeptide Y (NPY), a 36 amino acid hormone of the pancreatic polypeptide family, and subtype selective analogues have been synthesized by solid phase peptide synthesis. The peptides were labelled with Cy3, a commercially available fluorescent marker based on a cyanine dye, by solid phase strategy. During the cleavage a partial fragmentation of the fluorescent marker occurred. This has been investigated by means of HPLC and electrospray mass spectrometry. The labelled analogues of NPY showed high affinity to the NPY receptor subtypes Y1 and Y2. Thus, Cy3-NPY, Y1-selective Cy3-[Pro34] NPY and Y2 selective Cy3-[Ahx5-24] NPY were used to label SK-N-MC- and SMS-KAN-cells, which are stably expressing the Y1-(SK-N-MC) and the Y2-receptor subtype (SMS-KAN). The binding of the labelled analogues to the receptors was reversible and specific. The photoactivatable analogue, [(Tmd)Phe27] NPY, which showed high affinity to both receptor subtypes was labelled with Cy3 in solution. Whereas the fluorescent labelling of the cells with analogues without photoactivatable amino acid was reversible, successful photocrosslinking could be investigated by the irreversible staining of the cells using Cy3-[(Tmd)Phe27] NPY. These subtype selective analogues are exciting tools to trace receptors in tissues and to identify the pharmacologically characterized subtypes without radioactivity. 相似文献
159.
DNA- and RNA-hydrolyzing antibodies from the blood of patients with various forms of viral hepatitis
AG Baranovsky VG Matushin AV Vlassov VG Zabara VA Naumov R Giege VN Buneva GA Nevinsky 《Canadian Metallurgical Quarterly》1997,62(12):1358-1366
Antibodies (Abs) hydrolyzing proteins, DNA, and RNA are detected in the blood of patients with various autoimmune diseases. In the present work, homogeneous preparations of IgG Abs from the blood of the healthy donors as well as patients with A, B, C, and delta types of viral hepatitis, influenza, pneumonia, tuberculosis, tonsillitis, duodenal ulcer, and some types of cancer were purified. For the first time, the fraction of IgG and its Fab fragments of patients with viral hepatitis were shown to have high DNA- and RNA-hydrolyzing activity. In case of Abs from the healthy donors and patients with other diseases, high activity of Abs was not detected. The data obtained by various methods indicate that the activity of hepatitis Abs is an intrinsic property of the immunoglobulins. The relative rates of hydrolysis of cCMP, poly(U), poly(A), poly(C), and tRNA(Phe) by hepatitis Abs were compared with those of RNase A and other RNases from human blood. Significant differences in activities of Abs and nucleases in hydrolysis of model substrates were demonstrated. Thus, catalytically active Abs can appear in the blood of patients not only with autoimmune disorders, but with viral diseases as well. 相似文献
160.
ER Nekrasova DM Berman RR Rustandi HE Hamm AG Gilman VY Arshavsky 《Canadian Metallurgical Quarterly》1997,36(25):7638-7643
RGS proteins (regulators of G protein signaling) constitute a newly appreciated group of negative regulators of G protein signaling. Several members of this group stimulate the guanosine triphosphatase (GTPase) activity of various G protein alpha-subunits, including the photoreceptor G protein, transducin. In photoreceptor cells transducin GTPase is known to be substantially accelerated by the coordinated action of the gamma-subunit of its effector enzyme, cGMP phosphodiesterase (PDE gamma), and another yet unidentified membrane-associated protein factor. Here we test the possibility that this factor belongs to the RGS family of GTPase stimulators. We report a detailed kinetic analysis of transducin GTPase activation by two members of the RGS family, RGS4 and G alpha interacting protein (GAIP). RGS4, being at least 5-fold more potent than GAIP, stimulates the rate of transducin GTPase by 2 orders of magnitude. Neither RGS4 nor GAIP requires PDE gamma for activating transducin. Rather, PDE gamma causes a partial reversal of transducin GTPase activation by RGS proteins. The effect of PDE gamma is based on a decreased apparent affinity of RGS for the alpha-subunit of transducin. Our observations indicate that GTPase activity of transducin can be activated by at least two distinct mechanisms, one based on the action of RGS proteins alone and another involving the cooperative action of the effector enzyme and another protein. 相似文献