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201.
Two hundred twenty-seven cardiac transplant procedures have been performed in 206 patients from January, 1968, to April, 1981. Postoperative survival rates, calculated by the actuarial method for program years 1968 to 1973 (66 patients), are 44%, 33%, 27%, 21%, and 18% at 1, 2, 3, 4, and 5 years after transplantation, respectively. Postoperative survival rates for program years 1974 to 1981 (140 patients) are 63%, 55%, 51, 44%, and 39% at 1, 2, 3, 4, and 5 years after transplantation, respectively. This increase results primarily from improvement in survival achieved in the first 3 postoperative months (59% +/- 7%, 1968 to 1973, versus 80% +/- 40%, 1974 to 1980), reflecting improved patient management. Infection remains the primary cause of death following transplantation (76/131 patients, 58%), followed by acute rejection (24/181, 18.3%), graft arteriosclerosis (14/131, 10.7%), and malignancy (6/131, 4.6%). The development of graft arteriosclerosis has been examined in 85 one-year survivors studied by annual coronary arteriograms. Coronary lesions of varying severity have developed in 21 patients. HLA-A2 incompatibility was associated with a higher incidence of graft arteriosclerosis than was apparent for all other A locus incompatibilities (p less than 0.0003). Lymphoma has been shown to be associated with younger recipient age, a primary disease diagnosis of idiopathic cardiomyopathy, and retransplantation. One hundred six patients have survived at least 1 year after transplantation; 97% were in NYHA Class 1 at that time interval and 82% returned to employment or activity of choice. The longest survival time is new 11 years, 3 months. Cardiac transplantation can be considered "reasonable and therapeutic treatment to extend life" in selected individuals.  相似文献   
202.
The authors analyzed the mechanical behavior of the calf pericardium employed in the construction of valve leaflets for cardiac bioprostheses. Forty samples of pericardium were subjected to uniaxial tensile testing, 20 as controls and 20 exposed to loads increasing stepwise until rupture, with a return to zero load between each new increment. Another 20 samples were used similarly in biaxial tensile tests involving loads increasing stepwise until rupture, again returning to zero load between steps. The ultimate stresses in the uniaxial study were very similar and were not influenced by the region of pericardial tissue being tested or the increments in load to which the tissue was exposed. The mean stresses at rupture in the stepwise biaxial assays were significantly greater (p<0.01). Using morphological and mechanical criteria for sample selection, it was possible to obtain mathematical fits for the stress/strain relationship in both types of assays, with excellent coefficients of determination (R 2>0.90). In uniaxial tests in which the selection criteria were not applied, the correlation improved as the load increased, a phenomenon that did not occur in the biaxial studies. The values varied throughout the different cycles, adopting exponential forms when the strain was greatest. These variations, which demonstrate that the increase in the energy consumed is a function of the stress applied and of the strain produced, should be good parameters for assessing the changes in the collagen fiber architecture of pericardial tissue subjected to cyclic stress, and may help to detect early failure.  相似文献   
203.
The genetic diversity of 88 Streptococcus suis serotype 2 isolates which were recovered from various countries was examined by randomly amplified polymorphic DNA (RAPD) analysis with three primers. This bacterial collection included 80 isolates of porcine origin and 8 of human origin. This investigation allowed the identification of 23 RAPD types containing 1 to 30 isolates originating from one to six countries. Common RAPD patterns were found between human and pig isolates. The isolates were also tested for the production of virulent factors such as hemolysin, muramidase-released protein (MRP), and extracellular factor (EF). All isolates exhibiting the virulent phenotype hemolysin+ MRP+ EF+ clearly clustered on the basis of fingerprinting by RAPD analysis. In a similar way, most of isolates with the hemolysin- MRP- EF- phenotype were assigned to one RAPD cluster. Therefore, RAPD clusters are more related to the phenotype defined with hemolysin, MRP, and EF than to the geographic origin of the isolates. These data indicate that RAPD analysis used in conjunction with phenotypic methods provides a reliable method for the assessment of the clonal relationship between S. suis isolates responsible for infections in pigs or humans, especially for those exhibiting the classic "virulent" phenotype hemolysin+ MRP+ EF+.  相似文献   
204.
The Ras protein and its homolog, Rap1A, have an identical "effector region" (residues 32-40) preceded by Asp30-Glu31 and Glu30-Lys31, respectively. In the complex of the "Ras-like" E30D/K31E mutant Rap1A with the Ras-binding domain (RBD), residues 51-131 of Raf-1, Glu31 in Rap1A forms a tight salt bridge with Lys84 in Raf-1. However, we have recently found that Raf-1 RBD binding of Ras is indeed reduced by the E31K mutation, but is not affected by the E31A mutation. Here, the "Rap1A-like" D30E/E31K mutant of Ras was prepared and shown to bind the Raf-1 RBD less strongly than wild-type Ras, but slightly more tightly than the E31K mutant. The backbone 1H, 13C, and 15N magnetic resonances of the Raf-1 RBD were assigned in complexes with the wild-type and D30E/E31K mutant Ras proteins in the guanosine 5'-O-(beta,gamma-imidotriphosphate)-bound form. The Lys84 residue in the Raf-1 RBD exhibited a large change in chemical shift upon binding wild-type Ras, suggesting that Lys84 interacts with wild-type Ras. The D30E/E31K mutant of Ras caused nearly the same perturbations in Raf-1 chemical shifts, including that of Lys84. We hypothesized that Glu31 in Ras may not be the major salt bridge partner of Lys84 in Raf-1. A molecular dynamics simulation of a model structure of the Raf-1 RBD.Ras.GTP complex suggested that Lys84 in Raf-1 might instead form a tight salt bridge with Asp33 in Ras. Consistent with this, the D33A mutation in Ras greatly reduced its Raf-I RBD binding activity. We conclude that the major salt bridge partner of Lys84 in Raf-1 may be Asp33 in Ras.  相似文献   
205.
Whole-cell voltage and current recordings were obtained from red and green cone photoreceptors in isolated retina from macaque monkey. It was demonstrated previously that the cone photovoltage is generated from two sources, phototransduction current in the cone outer segment and photocurrent from neighboring rods. Rod signals are likely transmitted to cones across the gap junctions between rods and cones. In this study, the "pure" cone and rod components of the response were extracted with rod-adapting backgrounds or by subtracting the responses to flashes of different wavelength equated in their excitation of either rods or cones. For dim flashes, the pure cone component was similar in waveform to the cone outer segment current, and the rod component was similar to the photovoltage measured directly in rods. With bright flashes, the high frequencies of the rod signal were filtered out by the rod/cone network. The two components of the cone photovoltage adapted separately to background illumination. The amplitude of the rod component was halved by backgrounds eliciting approximately 100 photoisomerizations sec-1 per rod; the cone component was halved by backgrounds of 8700 photoisomerizations sec-1 per cone. Coupling between rods and cones was not modulated by either dim backgrounds or dopamine. Voltage noise in dark-adapted cones was dominated by elementary events other than photopigment isomerizations. The dark noise was equivalent in magnitude to a steady light eliciting approximately 3800 photoisomerizations sec-1 per cone, a value significantly higher than the psychophysical estimates of cone "dark light."  相似文献   
206.
OBJECTIVE: To determine the relationship between matrix metalloproteinases (MMPs), their inhibitors, and the turnover of matrix molecules in articular cartilage from patients with osteoarthritis (OA). METHODS: Synovial fluid samples were collected from the knees of 54 patients with OA. Radiographic evaluations and magnetic resonance imaging were performed on the knees of 34 OA patients to classify the stage of the disease. Biochemical analyses and immunoassays were used to measure the concentrations of MMP-1, MMP-3, tissue inhibitor of metalloproteinases 1 (TIMP-1), TIMP-2, the disaccharide of hyaluronic acid, the proteoglycan glycosaminoglycan disaccharides of chondroitin 4-sulfate (delta di-CS4) and chondroitin 6-sulfate (delta di-CS6), the 846 epitope on chondroitin sulfate of cartilage proteoglycan aggrecan (putative biosynthetic marker), the keratan sulfate (KS) epitope of aggrecan (putative degradation marker), and the C-propeptide of cartilage type II procollagen (CPII) (biosynthetic marker). RESULTS: The concentration of TIMP-1 was directly correlated with the levels of MMP-1 and MMP-3 (both were also correlated with each other), confirming earlier results. There was an inverse correlation between the delta di-CS6:delta di-CS4 ratio and the concentration of MMP-3. The level of delta di-CS6 was correlated with that of the KS epitope, and to a lesser degree, with that of the 846 epitope (the latter was also correlated with the level of delta di-CS4). The concentration of TIMP-1 correlated with that of the 846 epitope, whereas TIMP-2 levels correlated with those of CPII. There were significantly lower concentrations of delta di-CS6, delta di-CS4, the 846 epitope, and CPII in synovial fluid from patients with late-stage OA. CONCLUSION: These observations suggest a link between proteolysis and inhibitor concentrations in OA cartilage. Production of TIMPs appears to be individually linked to the synthesis of specific cartilage molecules. The reduction in the amount of cartilage-matrix structural components suggests that there is a measurable loss of cartilage in the late stages of the disease, as suggested previously. The resultant composition of the cartilage suggests that the loss may primarily involve "resident" molecules originally present in healthy cartilage.  相似文献   
207.
208.
A 14-kDa protein was identified as a major component of mature oocytes of the leech Theromyzon tessulatum. This protein was, like vitellin, detected in the content of yolk granules and was purified by gel-permeation and ion-exchange chromatography. The yolk protein corresponded to an iron-binding protein which exists in a monomeric unglycosylated form and had no similarities to vitellin. However, a strong resemblance between this protein and sipunculid hemerythrin, a non-heme iron-binding protein, was observed on the basis of its characteristics including molecular mass, iron content, ultraviolet/visible spectrum, amino acid composition and N-terminal sequence. These similarities with hemerythrin and the accumulation of the protein in the oocyte justify the name ovohemerythrin given to the molecule. A coelomic-fluid protein immunologically related to ovohemerythrin was detected in vitellogenic animals. The protein was purified with the chromatographic procedure used to isolate ovohemerythrin from oocytes and was found to be similar to the oocyte protein. This circulating ovohemerythrin was present in large amounts in the coelomic fluid while gametogenesis is in progress, i.e. after the third and last blood meal of the animal (stage 3), except at the time of oocyte enlargement when its concentration decreases dramatically. However, in contrast to vitellogenin, which is detected specifically in the coelomic fluid of leeches at stage 3, circulating ovohemerythrin is also observed after the first (stage 1) and second (stage 2) blood meal. This observation suggests a more complex function for ovohemerythrin than being merely a yolk nutrient for the embryo.  相似文献   
209.
This study was undertaken to clarify several aspects of morphological and taxonomic characters of Physaloptera bispiculata Vaz and Pereira, 1935, a parasite of the water rat, Nectomys squamipes. The cephalic structures (including lips, papillae, teeth, amphids, and porous areas) and details of the posterior end of male and female adult worms were examined by scanning electron microscopy, leading to the addition of new taxonomic characters for this species. We consider P. bispiculata a valid species, based on a comparative analysis of the specific characters for P. bispiculata and P. getula Seurat, 1917, including the morphology and morphometry of body structures as well as number and disposition of caudal papillae of the males.  相似文献   
210.
The aim of this study is to present a new classification of nasal polyps. This classification is based both on morphologic criteria relating to morphonuclear features from isolated Feulgen-stained nuclei and on glycohistochemical characteristics from histologic slides submitted to three lectins (peanut, wheat germ, and gorse seed agglutinins) and one neoglycoconjugate glycohistochemical stain. While the morphonuclear features (including 30 variables) relate essentially to chromatin pattern, the glycohistochemical stains (including 16 variables) are linked to the presence of specific carbohydrate moieties in cell membranes and cytoplasm. Forty-nine nasal polyps, including single polyps, diffuse polyposis, cystic fibrosis-related polyposis, and aspirin idiosyncracy-related polyposis associated with asthma, were thus characterized. All the variables were obtained quantitatively by means of computer-assisted microscopy. Two complementary methods of data classification were used to determine the actual diagnostic value contributed by each quantitative variable, namely, discriminant analysis, which forms part of multifactorial statistical analysis, and the decision tree technique, which is an artificial intelligence-related algorithm. The data so obtained show that our morphologic classification of nasal polyps fits in with the classification of nasal polyps defined on the basis of clinical criteria.  相似文献   
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