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91.
In a population-based case-control study of women in Missouri (United States), most of whom were smokers, we obtained information on adult diet to evaluate the effects of dietary fats in relation to lung cancer risk. All newly diagnosed, primary lung cancer cases among women 35 to 84 years of age reported to the Missouri Cancer Registry from 1 January 1993 to 31 January 1994 were invited to participate, as were population-based controls. The analysis focused on interviews obtained from 624 controls and 587 cases. In-person interviews were obtained from 99.0 percent of controls and 60.6 percent of cases. Age and energy-adjusted relative risks suggested a direct relation between risk of lung cancer and intake of dietary fats (e.g., total fat, saturated fat) and frequency of meat consumption. After adjusting for confounders, dietary fats were no longer associated with risk, but the adverse effect of frequent consumption of meat persisted. Risk was elevated about 90 percent (95 percent confidence interval = 1.2-3.0) among women in the highest quintile of red meat intake compared with those in the lowest quintile. Risk estimates associated with red meat consumption, however, were dependent on interview status; the effect was restricted to cases whose dietary information was provided by proxy. In summary, after adjusting for potential confounders and removing data obtained from proxy respondents, dietary fats and consumption of red meat were not associated with lung cancer risk among women in Missouri.  相似文献   
92.
The entorhinal cortex (ERC) has been implicated in the pathophysiology of Alzheimer's disease, schizophrenia and other disorders affecting cognitive functions. While powerful anatomical and histochemical methods (immunohistochemistry, in situ hybridization, etc.) may be applied (although with limitations) to postmortem human brain, each analysis should utilize a cytoarchitectonic approach to provide appropriate comparisons within the subdivisions of the ERC. Accordingly, we describe here the normal cyto- and myeloarchitecture of the human ERC as a prerequisite for the accompanying study of this region in schizophrenia. Our parcellation of this cortex differs from previous treatments in three ways. First, we adopted specific criteria of inclusion to define each subdivision of the region. Although distinctive ERC features are most prominent in the intermediate portion of this region, at least one of these features was considered the minimum necessary criterion to include adjacent tissue in the entorhinal area. Second, we used morphometric measurements (neuronal size and density as well as subdivisional volume and laminar thickness) to support our qualitative evaluation. Third, we have applied to the human ERC the conventional cytoarchitectonic nomenclature of the entorhinal cortex used previously in studies of non-human primates. This allows a more accurate extrapolation of the available numerous experimental anatomical, physiological and psychological data on this region to the human. As in the monkey, the five main subareas were recognized in the human (prorhinal, lateral, intermediate, sulcal and medial) but three required further subdivision (intermediate, sulcal and medial). The morphometric results obtained suggested a progression of the human entorhinal cortex from the peripheral to the central subareas, with the intermediate subarea (281) as the most complete entorhinal subdivision. Compared with non-human primates, the human ERC not only retains the basic periallocortical organization but also demonstrates further evolution. Taken together with available experimental data on the connectivity of this brain region, these results provide an anatomical basis for evaluating the ERC in human behavior.  相似文献   
93.
Herpesvirus saimiri strain 11 of subgroup A contains a gene called the saimiri transformation-associated protein, STP, which is not required for viral replication but is required for in vitro immortalization and for the lymphoma-inducing capacity of the virus. To assess the effects of sequence variation on STP function, STP genes from six subgroup A isolates were cloned and sequenced. Sequence comparisons revealed extensive amino acid substitutions within the central region, but the acidic amino terminus and the hydrophobic carboxyl terminus were well conserved. Amino acid identities varied from 73 to 99% among all two-way comparisons. The highly conserved YAEV/I motif at amino acid residues 115 to 118 was preceded by negatively charged glutamic acid residues and thus matched very well the consensus sequence for binding to SH2 domains of src family kinases. The STPs of these subgroup A strains were shown to associate with cellular src and to be an in vitro substrate for src kinase. Mutational analysis of STP-A11 showed that binding to src kinase required the tyrosine residue at 115, showing that YAEV/I is a likely binding motif for src. Also, tyrosine phosphorylation of STP-A11 by src led to subsequent binding to lck and fyn in vitro. Thus, the association of STP with src is likely to be important for T-cell transformation by subgroup A strains of herpesvirus saimiri.  相似文献   
94.
The Escherichia coli NarX, NarQ, NarL and NarP proteins comprise a two-component regulatory system that controls the expression of many anaerobic electron-transport and fermentation-related genes in response to nitrate and nitrite. Either of the two sensor-transmitter proteins, NarX and NarQ, can activate the response-regulator proteins, NarL and NarP, which in turn are able to bind at their respective DNA regulatory sites to modulate gene expression. NarX contains a conserved 17 amino acid sequence, designated the 'P-box' element, that is essential for nitrate sensing. In this study we characterize narQ mutants that also confer altered nitrate control of NarL-dependent nitrate reductase (narGHJI) and fumarate reductase (frdABCD) gene expression. While some narQ mutations cause the constitutive activation or repression of reporter-gene expression even when the cells are grown in the absence of the nitrate signal (i.e. a 'locked-on' phenotype), other mutations abolish nitrate-dependent control (i.e. a 'locked-off' phenotype). Interestingly the narQ (A42-->T) and narQ (R50-->Q) mutations along with the analogous narX18 (A46-->T) and narX902 (R54-->E) mutations also confer a 'locked-on' or a 'locked-off' phenotype in response to nitrite, the second environmental signal detected by NarQ and NarX. Furthermore, these narQ and narX mutations also affect NarP-dependent gene regulation of nitrite reductase (nrfABCDEFG) and aeg-46.5 gene expression in response to nitrite. We therefore propose that the NarQ sensor-transmitter protein also detects nitrate and nitrite in the periplasmic space via its periplasmic domain. A signal transduction model, which we previously proposed for NarX, is now extended to NarQ, in which a nitrate- or nitrite-detection event in the periplasmic region of the cell is followed by a signal transduction event through the inner membrane to the cytoplasmic domain of NarQ and NarX proteins to modulate their protein kinase/phosphatase activities.  相似文献   
95.
The Mattis Dementia Rating Scale (MDRS) is a commonly used cognitive measure designed to assess the course of decline in progressive dementias. However, little information is available about possible systematic racial bias on the items presented in this test. We investigated race as a potential source of test bias and differential item functioning in 40 pairs of African American and Caucasian dementia patients (N = 80), matched on age, education, and gender. Principal component analysis revealed similar patterns and magnitudes across component loadings for each racial group, indicating no clear evidence of test bias on account of race. Results of an item analysis of the MDRS revealed differential item functioning across groups on only 4 of 36 items, which may potentially be dropped to produce a modified MDRS that may be less sensitive to cultural factors. Given the absence of test bias because of race, the observed racial differences on the total MDRS score are most likely associated with group differences in dementia severity. We conclude that the MDRS shows no appreciable evidence of test bias and minimal differential item functioning (item bias) because of race, suggesting that the MDRS may be used in both African American and Caucasian dementia patients to assess dementia severity.  相似文献   
96.
This study extended Hanin's 1980 Zone of Optimal Functioning hypothesis by assessing both intensity and direction components of competitive state anxiety. 20 volunteer semiprofessional cricketers responded to the modified Competitive State Anxiety Inventory-2 prior to ten matches. For each game, players' performances were intraindividually evaluated by three qualified cricket coaches using subjective criteria. Separate Cognitive Anxiety and Somatic Anxiety 'below,' 'in,' and 'above' zones for Intensity and Direction of state anxiety were identified via repeated empirical assessments. Two two-way analyses of variance were computed for Intensity and Direction of anxiety (Cognitive Anxiety Zone Level x Somatic Anxiety Zone Level) with standardized performance scores as the dependent variable. A significant interaction was found between the zone levels for Cognitive and Somatic Anxiety Direction and performance scores. Examination of the Zone of Optimal Functioning hypothesis that focuses on the interactions between Cognitive and Somatic Anxiety and in particular the directional elements of the modified inventory seems warranted.  相似文献   
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The current adjustment of cochlear implant (CI) speech processors is based on a knowledge of the lower and upper limits (T- and C-levels) for electrical stimulus currents. These data are usually acquired from subjective classifications of individual patients. In cases with non-reliable patient responses, objective methods are necessary. Especially for the estimation of correct T-levels, auditory evoked potentials (AEP) can be applied, since they allow the determination of response thresholds in a frequency-specific manner. By determining the AEP of different latencies, late cortical responses can be registered almost without artifact contamination. These patients have been examined in 20 patients provided with 22- or 8-channel CI-systems (Nucleus or Med-EI implants). In all cases, clear responses and clearly discernible threshold transitions could be detected. By making use of acoustical stimulation in a free sound field, subjective hearing threshold and the T-levels of electrical stimulation could be verified. Since late responses are generated in the primary auditory cortex, their assessment permits a nearly integral functional control of the aided hearing system. To date, no problems have occurred from maturation or attentional effects in either pediatric or adult patients. The applicability in very young children remains to be explored.  相似文献   
100.
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