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911.
Yersinia pseudotuberculosis and Listeria have been shown to be capable of assimilating carbon dioxide from the air and using its carbon for the synthesis of biopolymers of the bacterial cell. These microorganisms, the causative agents of saprozoonotic infections, have also been found to be capable of assimilating molecular nitrogen from the air in small amounts. The data on the influence of the growth conditions of the cultures (hydrogen concentration, the presence of carbon dioxide and oxygen, temperature) on the activity of acetylene reduction by microbial cells. At low temperature molecular nitrogen is fixed by Listeria twice as actively as by Y.pseudotuberculosis. Not all bacterial strains under study have been found to be capable of acetylene reduction. The presence of fixed nitrogen in the medium suppresses the process of the reduction of acetylene into ethylene.  相似文献   
912.
Thrombopoietin (TPO) regulates early and late stages of platelet formation as well as platelet activation. TPO exerts its effects by binding to the receptor, encoded by the protooncogene c-mpl, that is expressed in a large number of cells of hematopoietic origin. In this study, we evaluated the expression of c-Mpl and the effects of TPO on human polymorphonuclear cells (PMN). We demonstrate that PMN express the TPO receptor c-Mpl and that TPO induces STAT1 tyrosine phosphorylation and the formation of a serum inducible element complex containing STAT1. The analysis of biological effects of TPO on PMN demonstrated that TPO, at concentrations of 1-10 ng/ml, primes the response of PMN to n-formyl-met-leu-phe (FMLP) by inducing an early oxidative burst. TPO-induced priming on FMLP-stimulated PMN was also detected on the tyrosine phosphorylation of a protein with a molecular mass of approximately 28 kD. Moreover, we demonstrated that TPO by itself was able to stimulate, at doses ranging from 0.05 to 10 ng/ml, early release and delayed synthesis of interleukin 8 (IL-8). Thus, our data indicate that, in addition to sustaining megakaryocytopoiesis, TPO may have an important role in regulating PMN activation.  相似文献   
913.
914.
The concept of home emerged as a theme in the stories of inner strength told by older women. In this study, 12 women over the age of 65 (7 European American and 5 African American) were asked to tell a personal story that exemplified the meaning of being strong. The concept of home, which was an aspect of finding strength, comprised powerful stories about making a home, leaving home, losing one's home, staying home, and coming home. In this article, the meanings of home are presented in detail, as they emerged in this research. Conclusions concern the universal human need for creating a home and implications for nurses.  相似文献   
915.
Recent studies have shown that the alcohol metabolites malondialdehyde and acetaldehyde can combine to form a stable adduct (MAA) on proteins. This adduct has been detected in the livers of rats chronically consuming ethanol, and serum antibodies to MAA have been observed at significantly higher concentrations in ethanol-fed when compared with pair-fed or chow-fed control rats. More recently, preliminary studies have strongly suggested that the MAA adduct is capable of stimulating antibody responses to soluble proteins in the absence of adjuvants. The antibodies produced recognize either the MAA epitope or the carrier protein itself. Therefore, it was the purpose of this study to examine the potential immunogenicity of MAA-modified exogenous proteins in the absence of adjuvants. Balb/c mice were immunized in the presence or absence of adjuvant with different concentrations of unmodified or MAA-modified proteins. The antibody response to both the MAA epitope and unmodified protein epitopes were determined by ELISA. In the absence of adjuvant, significant antibody responses were induced to both the MAA epitope and nonmodified protein epitopes. Smaller immunizing doses of MAA-protein conjugate favored the production of antibodies to nonmodified proteins, whereas larger doses induced a strong anti-MAA response. In studies to begin determining a mechanism for the specificity of the response in the absence of adjuvants, peritoneal macrophages were found to bind and degrade MAA-adducted proteins through the use of a scavenger receptor. This indicated that MAA-adducted proteins may be specifically taken up and epitopes presented to the humoral immune system in the absence of adjuvants. Importantly, these are the first data showing that an alcohol-related metabolite can induce an antibody response in the absence of adjuvant and suggesting a mechanism by which antibody to the MAA adduct or its carrier (exogenous or endogenous) proteins may be generated in vivo.  相似文献   
916.
A mucinous cystadenocarcinoma along with remnants of normal pancreatic tissue was discovered in the spleen of a 21-year-old woman. Extensive clinical, radiological, ultrasound and computed tomography investigation revealed that the patient's pancreas and ovaries were unremarkable. We presume an origin from heterotopic pancreatic tissue for this neoplasm and present a review of the literature in this regard.  相似文献   
917.
Cytoplasmic sequestration of the p53 tumor suppresser protein has been proposed as a mechanism involved in abolishing p53 function. However, the mechanisms regulating p53 subcellular localization remain unclear. In this report, we analyzed the possible existence of cis-acting sequences involved in intracellular trafficking of the p53 protein. To study p53 trafficking, the jellyfish green fluorescent protein (GFP) was fused to the wild-type or mutated p53 proteins for fast and sensitive analysis of protein localization in human MCF-7 breast cancer, RKO colon cancer, and SAOS-2 sarcoma cells. The wild-type p53/GFP fusion protein was localized in the cytoplasm, the nucleus, or both compartments in a subset of the cells. Mutagenesis analysis demonstrated that a single amino acid mutation of Lys-305 (mt p53) caused cytoplasmic sequestration of the p53 protein in the MCF-7 and RKO cells, whereas the fusion protein was distributed in both the cytoplasm and the nucleus of SAOS-2 cells. In SAOS-2 cells, the mutant p53 was a less efficient inducer of p21/CIP1/WAF1 expression. Cytoplasmic sequestration of the mt p53 was dependent upon the C-terminal region (residues 326-355) of the protein. These results indicated the involvement of cis-acting sequences in the regulation of p53 subcellular localization. Lys-305 is needed for nuclear import of p53 protein, and amino acid residues 326-355 can sequester mt p53 in the cytoplasm.  相似文献   
918.
The demand-control/support model of work stress was tested in a sample of 419 correctional officers. The results suggest a link between certain work characteristics (high demands, low control, and low support) and strain symptoms (e.g., psychological distress, job dissatisfaction) as well as with negative affectivity (NA). On the other hand, other job characteristics (high demands and high control) were associated with positive behavioral outcomes (seeking feedback, looking at work as a challenge). Workers in high-isolation strain jobs with the greatest work exposure showed higher levels of strain and NA than workers with less experience working in the same job. Results suggest that work experience may affect long-term personality evolution. It is concluded that studies that control for the nuisance aspects of trait NA may underestimate the impact of the work environment on strain.  相似文献   
919.
OBJECTIVE: The purpose of the study was to compare staff versus patient perceptions of the causes and emotional impact of verbal and physical aggression on a psychiatric inpatient unit, and the corrective measures each group would endorse. METHODS: Fifty-four patients and 32 nursing staff members responded to similar questions about physical and verbal aggression. They also reported their emotional responses to aggression and steps they would endorse to reduce aggression at the medical center. Data was analyzed by chi-square tests for proportion comparisons between groups. RESULTS: "Verbal Abuse" was viewed an important contributor to physical aggression. Staff stressed patient substance abuse and violent lifestyles. Patients focused on the use of involuntary procedures and cultural differences between patients and staff. CONCLUSIONS: Patients endorsed more restrictive safety measures as long as the measures such as metal detectors and searches were applied to staff and visitors, as well as patients. Patients requested more input into decision-making processes through patient-staff workgroups.  相似文献   
920.
New genes for male accessory gland proteins in Drosophila melanogaster   总被引:1,自引:0,他引:1  
The accessory gland of male insects produces components of the seminal fluid that alter the behavior, physiology and life span of the mated female, and contribute to her efficient storage and utilization of sperm. As a step towards understanding how this occurs, we have isolated genes encoding 12 previously unreported accessory gland-specific mRNAs from the fruit fly Drosophila melanogaster. We report here the restriction maps of the new genes, the chromosome positions--which are all autosomal--of the 11 non-repetitive genes, their expression patterns, and the sequences of the accessory gland proteins (Acps) encoded by nine of the genes. Eight of the proteins predicted from these sequences begin with putative secretion signals. Following their signal sequences, three of the predicted molecules are peptides and the other five are larger polypeptides with characteristics of cleavable prohormones. The ninth molecule, which has an N-terminal hydrophobic region but no consensus signal peptide cleavage site, is predicted to be a 716 amino acid glycoprotein. Of the nine proteins, two have intriguing similarities to sequences in protein databases. Acp76A is a 388 amino acid pro-protein which contains a signature sequence for the serpin class of protease inhibitors. The 115 amino acid Acp62F has a 28 amino acid region of high sequence similarity to a neurotoxin of the Brazilian armed spider Phoneutria nigriventer. Models are discussed in which Acp76A plays a role in the observed regulation of Acp proteolysis and/or in the coagulation of seminal fluid to form a mating plug, and in which Acp62F contributes to the reported toxicity of Drosophila seminal fluid.  相似文献   
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