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91.
Chemical analyses returned by Mars Pathfinder indicate that some rocks may be high in silica, implying differentiated parent materials. Rounded pebbles and cobbles and a possible conglomerate suggest fluvial processes that imply liquid water in equilibrium with the atmosphere and thus a warmer and wetter past. The moment of inertia indicates a central metallic core of 1300 to 2000 kilometers in radius. Composite airborne dust particles appear magnetized by freeze-dried maghemite stain or cement that may have been leached from crustal materials by an active hydrologic cycle. Remote-sensing data at a scale of generally greater than approximately 1 kilometer and an Earth analog correctly predicted a rocky plain safe for landing and roving with a variety of rocks deposited by catastrophic floods that are relatively dust-free.  相似文献   
92.
A group of 48 patients, consecutive apart from exclusions, from a 1-year series of 60 cases of aneurysmal subarachnoid haemorrhage (SAH), was reviewed, in respect of clinical and radiological features, surgical management, clinical outcome, psychological distress and psychometric status, the neuropsychological assessment being compared with a closely-matched group of controls, the postoperative assessment being accompanied by a single positron emission computed tomogram (SPECT) scan. A review of those features which might have been expected to have a bearing on cognitive outcome (CT abnormalities at the outset, angiographic vasospasm, operative aneurysmal leakage, temporary vessel occlusion) failed to show a significant difference on cognitive tests. There was, however, a cognitive deficit shown by the patient group as a whole, when compared with the controls. Thus, SAH itself, the initial insult, would appear to be the essential factor in the production of persistent cognitive deficits.  相似文献   
93.
Understanding the antibody response in HIV-1 infection is important to vaccine design. We have studied the antibody response to HIV-1 envelope at the molecular level and determined the characteristics of neutralizing and non-neutralizing antibodies. These antibodies were isolated from phage display libraries prepared from long-term seropositive asymptomatic individuals. The HIV-1 envelope is presented to the immune system in several antigenically distinct configurations: unprocessed gp160, gp120 and gp41 subunits and native envelope, each of which may be important in eliciting an antibody response in HIV-1 infection. The antibodies tested characteristically had poor affinities for native envelope as expressed on the surface of virions or infected cells, but had high affinities against non-native forms of HIV-1 envelope (viral debris). An exceptionally potent neutralizing antibody in contrast, bound native envelope with equivalent or somewhat higher affinity than this. This indicates that the antibody response in HIV-1 infection is principally elicited by viral debris rather than virions, and that these antibodies bind and neutralize viruses sub-optimally. Potential vaccines should be designed to elicit responses against native envelope.  相似文献   
94.
We performed a case-control study to investigate the association of the poor metaboliser genotype of the cytochrome P450 2D6 gene with Parkinson's disease (PD). Genotyping was determined by the polymerase chain reaction followed by digestion with restriction enzymes. The poor metaboliser genotype was more frequent in 112 patients with PD than in 206 matched controls (odds ratio 1.7, 95% CI: 0.94-2.45). A meta-analysis of these results together with ten other published studies gave a pooled odds ratio for the poor metaboliser genotype of 1.47 (95% CI: 1.18-1.96, P=0.01). Thus, the poor metaboliser genotype has a small but highly significant association with PD which would be easily missed in small studies. Research now should focus on the mechanism of this association.  相似文献   
95.
The M. longissimus from lambs electrically stimulated at 15 min post-mortem were removed after grading, wrapped in polythene film and held at 4 (n = 6), 7 (n = 6), 15 (n = 6, n = 8) and 35 °C (n = 6), until rigor mortis then aged at 15 °C for 0, 4, 24 and 72 h post-rigor. Centrifuged free water increased exponentially, and bound water, dry matter and shear force decreased exponentially over time. Decreases in shear force and increases in free water were closely related (r2 = 0.52) and were unaffected by pre-rigor temperatures.  相似文献   
96.
We investigated the relationship between stress responsiveness and meat quality in cattle. The cattle were 16-19-month-old Mixed (n=37, 303 kg) or Non-mixed (n=23, 279 kg) Friesian bulls and Friesian cull cows (1.5-7 years) that were classified Unfinished (n=133, 195 kg) or Finished for 3 months (n=34, 252 kg). A portion of m. longissimus lumborum (LL) muscle was obtained from consecutive animals for a single days slaughter of 227 cattle processed through a hot boning plant. Catecholamines were obtained from bladder urine. Ultimate pH, lactate, glycogen, glycolytic potential and representative sarcomere lengths were determined from 20-h muscle samples. Shear force measurements were from meat aged at 15 °C for 20 and 90 h. Urinary noradrenaline was similar between Mixed (14.86 ng/μmol creatinine) and Non-mixed bulls (14.07 ng/μmol creatinine) and Finished cows (15.24 ng/μmol creatinine) and elevated in the Unfinished cows (22.28 ng/μmol creatinine). Urinary adrenaline was higher in Mixed bulls (9.5 ng/μmol creatinine) than Non-mixed bulls (5.7 ng/μmol creatinine) and higher in both Unfinished cows (16.67 ng/μmol creatinine) and Finished cows (14.19 ng/μmol creatinine). For bulls that are growing well on-farm, with a only short period of fasting prior to slaughter, pH(u) is a good predictor of meat tenderness. In this situation, stressors that lower muscle glycogen pre-slaughter can have a significant effect on meat shear force, and individual animals with elevated urinary adrenaline were the most susceptible. However, in the case of cows, adrenaline responses are not necessarily associated with glycogen depletion and pH(u) is less affected than for bulls. Furthermore, the ability of meat to tenderise fully, related to reduced proteolytic turnover, is reduced in nutritionally compromised animals such as the Unfinished cows.  相似文献   
97.
In this study four strains of lactic acid bacteria (LAB) were chosen to bioacidify a mash containing 50% barley and 50% malt. The strains were isolated from malted and unmalted barley and assayed for extracellular enzymatic activities (proteases, amylases, β‐glucanases). The biologically acidified mash was compared to a chemically acidified mash, 100% malt mash un‐acidified and 50% malt and 50% barley mash unacidified. Characteristics such as pH, extract, colour, viscosity, total soluble nitrogen (TSN), free amino nitrogen (FAN), apparent fermentability, β‐glucan and lautering performance of the resultant worts were determined. A model lautering system replicating one used in a brewery was designed and built in University College Cork (UCC) to measure the lautering performance of the bioacidified mashes. The new system was compared to the filtration method used in EBC method 4.5.1. Overall the addition of LAB to bioacidify a mash of 50% barley and 50% malt resulted in faster filtration times, which correlated with decreased β‐glucan levels. Proteolytic LAB had a positive influence on the quality of wort and resulted in increased FAN levels. Lighter colour worts were observed along with increased extract levels.  相似文献   
98.
ABSTRACT: The ability of 13 different strains of psychrotrophs to release free fatty acids in milk was evaluated by using GC analysis. The 13 strains could be categorized into 3 groups: Group 1 consisted of bacteria that grew well and released large quantities of free fatty acids, group 2 consisted of bacteria that grew well but released low amounts of free fatty acids, and group 3 consisted of bacteria that did not grow well nor released large quantities of fatty acids. In group 1, 3 strains were determined to be highly lipolytic, releasing short‐chain fatty acids in amounts greater than reported threshold values. Group 3 consisted of 2 strains, which did not grow well in heat‐treated milk, and the subsequent release of free fatty acids was minor during the 10‐d monitoring time. The other 8 strains tested showed no specific pattern of fatty acid release and quantities of short‐chain fatty acids were not large, despite the ability to grow to high numbers in the treated milk. This work indicates that the lipolytic activity of psychrotrophs common in raw milk is specific to the species and a general prediction of free fatty acid release may not be possible.  相似文献   
99.
This paper presents air toxics emissions test results from a pilot-scale cofiring study of pentachlorophenol- (PCP) and creosote-treated woods to provide data for pre-permitting requirements for utilities interested in biomass cofiring as a means of increasing renewable energy while reducing greenhouse gases and other emissions for pulverized coal-fired utility boilers. These PCP/creosote-treated wood cofiring tests included a comprehensive assessment of air toxics, including dioxins, furans, polycyclic aromatic hydrocarbons (PAHs), heavy metals (Hg, Sb, As, Cd, Cr, Co, Pb, Ni and Se), formaldehyde and other volatile organic compounds, HCl, and particulates. This pilot-scale testing measured ‘uncontrolled’ emissions from the combustor (upstream of flue gas cleanup devices) and showed that PCP/creosote-treated wood could be successfully cofired at 10% heat input without increases in air toxic emissions as compared to a baseline eastern bituminous coal. Air toxics emissions were typically very low, and often near or below detection limits, largely as a result of the good air/fuel mixing and high furnace temperatures associated with pulverized coal combustion. One expected result was an increase in uncontrolled HCl emissions as a result of the higher chlorine content in the treated woods, although even at 10% cofiring levels, HCl emissions were within the range of other US coals. This paper is presented to provide independent data that industry, environmental groups, and regulators may consider in evaluating the opportunities for treated wood cofiring test burns and commercialization in full-scale coal-fired boilers in an environmentally acceptable manner.  相似文献   
100.
This paper reports on a fully structured interview survey, using a multisectional questionnaire, of experienced construction contract price forecasters. The aim of the research was to investigate the relationship between the accuracy of “early-stage” forecasts and experience (defined in terms of the forecasters' length of service as a forecaster and the number of forecasts prepared), learning styles, and approaches to learning. The results show that, although the forecasters rated experience very highly, the relationships between their ability to learn from experience, measured in terms of individual learning styles and approaches to learning, and the quality of their forecasts were found to be very different from those anticipated. No significant correlations were found between forecasting accuracy and the experience measures used, except for the approaches-to-learning dimensions labeled Risk taking, Insecurity, and Self-confidence. The results for the Insecurity and Self-confidence dimensions suggest that balanced forecasters (i.e., those who were neither insecure nor overconfident) produce more consistent forecasts. Similarly, the results for the Risk-taking dimension indicate that high-risk takers tend to underestimate whereas those who are more conservative tend to overestimate contract prices.  相似文献   
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