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91.
Stahl CA  Berg EP 《Meat science》2003,64(2):169-174
The objective of this study was to evaluate the growth and meat quality of hogs supplemented with creatine monohydrate (CMH) and (or) a simple carbohydrate (dextrose) for the last 30 days of production. Crossbred market barrows (n=32; 75 kg) were blocked by weight and randomly allotted to one of eight pens with four animals per pen. Dietary treatments were a control (normal corn and soybean meal diet), CMH (control diet supplemented with 0.55% CMH), DEXT (control diet supplemented with 2.1% dextrose), and COMBO (control diet supplemented with CMH and DEXT). Average daily gain on test, fat depth, hot carcass weight, and LMA (postmortem dot grid measurement) were not affected by dietary treatment. However, a nonsignificant trend (P=0.07) was observed for 10th rib loin muscle area (LMA) gain on test as determined by real-time ultrasound comparisons over the course of the 30 days feeding duration (COMBO=4.24 cm(2) increase vs. control=1.0 cm(2) increase). No significant differences in pork quality were noted across treatment groups.  相似文献   
92.
Transformants of bakers' yeast (Saccharomyces cerevisiae) can be generated when non-growing cells metabolize sugars (without additional nutrients) in the presence of plasmid DNA. These results suggest that there is a mechanism by which DNA can naturally be taken up by the yeast cell. Natural transformation does not take place in common complete or minimal yeast culture media such as YPD and YNB. The starvation conditions used in our experiments thus seem to be an important prerequisite for such transformation events.  相似文献   
93.
A complete quantitative account of P. Wason's (1966) abstract selection task is proposed. The account takes the form of a mathematical model. It is assumed that some response patterns are caused by inferential reasoning, whereas other responses reflect cognitive processes that affect each card selection separately and independently of other card selections. The model parameters assess the contributions of different interpretational, inferential, and heuristic factors that jointly determine performance in the selection task. The interpretation of most of the model parameters in terms of these different factors is validated experimentally. This model of the selection task is the first to account for the observed frequencies of all 16 possible response patterns that can arise. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
94.
We study asynchronously communicating open systems modeled as Petri nets with an interface. An accordance preorder describes when one open system can be safely replaced by another open system without affecting some behavioral property of the overall system. Although accordance is decidable for several behavioral properties if we assume a previously known bound on the maximal number of pending messages, we show that it is not decidable without this assumption.  相似文献   
95.
Phonological awareness (PA) has been operationally defined by many different tasks, and task comparisons have been confounded by differing levels of linguistic complexity among items. A sample of 113 kindergartners and first graders completed PA tasks designed to separate task difficulty from linguistic complexity. These measures were, in turn, compared with measures of early literacy. Results indicated that the measures loaded on a single factor and that PA measured by differences in linguistic complexity, rather than by task differences, seemed to be more closely related to the factor. A logical analysis suggested that alphabet knowledge is necessary for children to separate onsets from rimes and that awareness of onsets and rimes is necessary both for word reading and for more complex levels of phonemic analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
96.
For many organisms, meiotic double crossing over is less frequent than expected on the assumption that exchanges occur at random with respect to each other. This "interference," which can be almost total for nearby intervals, diminishes as the intervals in which the double crossovers are scored are moved farther apart. Most models for interference have assumed, at least implicitly, that the intensity of interference depends inversely on the physical distance separating the intervals. However, several observations suggest that interference depends on genetic distance (Morgans) rather than physical distance (base pairs or micrometers). Accordingly, we devise a model in which interference is related directly to genetic distance. Its central feature is that recombinational intermediates (C's) have two fates--they can be resolved with crossing over (Cx) or without (Co). We suppose that C's are distributed at random with respect to each other (no interference); interference results from constraints on the resolution of C's. The basic constraint is that each pair of neighboring Cx's must have between them a certain number of Co's. The required number of intervening Co's for a given organism or chromosome is estimated from the fraction of gene conversions that are unaccompanied by crossover of flanking markers. The predictions of the model are compared with data from Drosophila and Neurospora.  相似文献   
97.
The main benefit, the economical manufacturability of traditional gear profiles, such as an involute, are no longer of major importance in times of computer-aided design and production. Due to existing modern production techniques standard and more sophisticated gear types can be produced with high precision and maintainable financial effort. Especially for non-standard gear types modern gear production systems ensure high quality and reliability to the operator with regard to flank and meshing geometry. Depending on the context of application different gear types have advantages and disadvantages concerning load carrying capacity, effectiveness or noise excitation. Developing an optimized gearing for the desired application is thus a complex and elementary goal within the design process.  相似文献   
98.
Since February 1996 we have prospectively assessed residual adrenal autonomy by the fludrocortisone suppression test (FST) in 23 patients 3 months after unilateral adrenalectomy for Conn syndrome and in 45 patients after a longer interval. In regard to blood pressure, 36 (53%) patients were cured of hypertension and the remaining 32 (47%) patients had improved hypertension control at the time of their latest postoperative clinical assessment. In regard to the outcome of surgery, patients who achieved normal suppressibility of aldosterone were regarded as cured, and those who had greater suppressibility after surgery were considered improved. Time since surgery for the whole group averaged 26 months. By these biochemical criteria, 42 patients (62%) were cured by surgery, and the rest improved; 16 (76%) of 21 women were cured, and 26 (55%) of 47 men. The women (mean +/- SD age 47 +/- 11 years) were significantly (p < 0.05) younger than the men (52 +/- 9 years). Preoperative aldosterone levels before and after FST were similar in the cured and improved groups and fell significantly (p < 0.01) in both groups following surgery. After surgical reduction of autonomous aldosterone production, mean plasma renin activity levels increased sixfold in the cured group and threefold in the improved group. Surgical mortality in this group of 68 patients with Conn syndrome was zero.  相似文献   
99.
Prostaglandin endoperoxide H synthases-1 and -2 (PGHS-1 and -2) are the major targets of nonsteroidal anti-inflammatory drugs like aspirin and ibuprofen. These enzymes catalyze the committed step in the formation of prostanoids from arachidonic acid. Although PGHS-1 and -2 are similar biochemically, a number of studies suggest that PGHS-1 and PGHS-2 function independently to form prostanoids that subserve different cellular functions. We have hypothesized that these isozymes may reside, at least in part, in different subcellular compartments and that their compartmentation may affect their access to arachidonic acid and serve to separate the functions of the enzymes. To obtain high resolution data on the subcellular locations of PGHS-1 and -2, we employed immunoelectron microscopy with multiple antibodies specific to each isozyme. Both PGHS-1 and -2 were found on the lumenal surfaces of the endoplasmic reticulum (ER) and nuclear envelope of human monocytes, murine NIH 3T3 cells, and human umbilical vein endothelial cells. Within the nuclear envelope, PGHS-1 and -2 were present on both the inner and outer nuclear membranes and in similar proportions. Western blotting data showed a similar distribution of PGHS-1 and -2 in subcellular fractions, and product analysis using isozyme-specific inhibitors suggested that both enzymes generate the same products in NIH 3T3 cells. Thus, we are unable to attribute the independent functioning of PGHS-1 and PGHS-2 to differences in their subcellular locations. Instead, the independent operation of these isozymes may be attributable to subtle kinetic differences (e.g. negative allosteric regulation of PGHS-1 at low concentrations of arachidonate (500-1000 nM)). A further conclusion of importance from a cell biological perspective is that membrane proteins such as PGHS-1 and -2, which are located on the lumenal surface of the ER, are able to diffuse freely among the ER and the inner and outer membranes of the nuclear envelope.  相似文献   
100.
Identification of a gene that causes primary open angle glaucoma   总被引:3,自引:0,他引:3  
Glaucoma is a major cause of blindness and is characterized by progressive degeneration of the optic nerve and is usually associated with elevated intraocular pressure. Analyses of sequence tagged site (STS) content and haplotype sharing between families affected with chromosome 1q-linked open angle glaucoma (GLC1A) were used to prioritize candidate genes for mutation screening. A gene encoding a trabecular meshwork protein (TIGR) mapped to the narrowest disease interval by STS content and radiation hybrid mapping. Thirteen glaucoma patients were found to have one of three mutations in this gene (3.9 percent of the population studied). One of these mutations was also found in a control individual (0.2 percent). Identification of these mutations will aid in early diagnosis, which is essential for optimal application of existing therapies.  相似文献   
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