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排序方式: 共有1680条查询结果,搜索用时 31 毫秒
991.
TL Yue J Ni AM Romanic JL Gu P Keller C Wang S Kumar GL Yu TK Hart X Wang Z Xia WE DeWolf GZ Feuerstein 《Canadian Metallurgical Quarterly》1999,274(3):1479-1486
TL1 is a recently discovered novel member of the tumor necrosis factor (TNF) cytokine family. TL1 is abundantly expressed in endothelial cells, but its function is not known. The present study was undertaken to explore whether TL1 induces apoptosis in endothelial cells and, if so, to explore its mechanism of action. Cultured bovine pulmonary artery endothelial cells (BPAEC) exposed to TL1 showed morphological (including ultrastructural) and biochemical features characteristic of apoptosis. TL1-induced apoptosis in BPAEC was a time- and concentration-dependent process (EC50 = 72 ng/ml). The effect of TL1 was not inhibited by soluble TNF receptors 1 or 2. TL1 up-regulated Fas expression in BPAEC at 8 and 24 h after treatment, and significantly activated stress-activated protein kinase (SAPK) and p38 mitogen-activated protein kinase (p38 MAPK). The peak activities of SAPK and p38 MAPK in TL1-treated BPAEC were increased by 9- and 4-fold, respectively. TL1-induced apoptosis in the BPAEC was reduced by expression of a dominant-interfering mutant of c-Jun (62.8%, p < 0.05) or by a specific p38 inhibitor, SB203580 (1-10 microM) dose-dependently. TL1 also activated caspases in BPAEC, and TL1-induced apoptosis in BPAEC was significantly attenuated by the caspase inhibitor, ZVAD-fluromethyl-ketone. The major component activated by TL1 in BPAEC was caspase-3, which was based on substrate specificity and immunocytochemical analysis. These findings suggest that TL1 may act as an autocrine factor to induce apoptosis in endothelial cells via activation of multiple signaling pathways, including stress protein kinases as well as certain caspases. 相似文献
992.
ZU Rahman DK Frye TL Smith L Asmar RL Theriault AU Buzdar GN Hortobagyi 《Canadian Metallurgical Quarterly》1999,85(1):104-111
BACKGROUND: The authors report results and long term follow-up for 1581 patients with metastatic breast carcinoma treated with doxorubicin-containing combination chemotherapy at a single institution; this report is meant to serve as a reliable reference for single-arm studies of newer therapies in this patient population. METHODS: Prospectively collected data from 18 successive doxorubicin-containing protocols for the treatment of metastatic breast carcinoma were evaluated. RESULTS: The response rate was 65.0% (95% confidence interval [CI]: 62.5-67.3%), complete response (CR) rate was 16.6% (95% CI: 14.8-18.6%), and partial response (PR) rate was 48.5% (95% CI: 46.0-50.9%). Median progression free survival (PFS) was 11.5 months (95% CI: 10.9-12.3 months) and median overall survival (OS) was 21.3 months (95% CI: 20.3-22.7 months). Survival correlated with response to therapy; median PFS and OS were 22.4 and 41.8 months, respectively, for the patients who achieved CR (n=263) and 14 and 24.6 months, respectively, for PR patients (n=766). The median OS of patients who had progressive disease during chemotherapy was 3.8 months. The response rate, PFS and OS correlated with number of organs involved and especially with tumor burden. Patients with hormone receptor-positive tumors had a similar response rate to that of patients with hormone receptor negative tumors but had significantly longer PFS (medians of 14.3 and 8.7 months, respectively) and OS (medians of 28.6 and 18.1 months, respectively). CONCLUSIONS: In patients with metastatic breast carcinoma, doxorubicin-containing chemotherapy had a response rate of 65% and a CR rate of 16.6%. PFS and OS were 11.5 months and 21.3 months, respectively, for all responders and 22.4 months and 41.8 months, respectively, for those who had CR. 相似文献
993.
Effects of PSE on the quality of cooked hams 总被引:1,自引:0,他引:1
Meat quality comparisons were carried out on hams produced from pork legs showing evidence of PSE and normal pork legs. Quality measurements included drip loss, sliceability, cooking loss, TBARS analysis and colour evaluation (Hunter L, a, b). A total of 40 pork legs were selected from a commercial slaughtering plant, 20 from carcasses showing PSE and 20 from normal carcasses based on L, a, b, and pH values. Carcass pH taken between the third/fourth rib was measured 45 min, 90 min, and 24 h after slaughter. Using a Minolta colorimeter (Hunter L, a, b,), colour of the Longissimus dorsi muscle was measured 24 h after slaughter. PSE had an adverse effect on cooked hams in comparison to normal cooked hams with respect to driploss (P<0.01), cooking loss (P<0.01), sliceability (P<0.01), colour (P<0.05) and lipid oxidation (P<0.05). Cooked hams manufactured from severe PSE pork in this study had an estimated financial loss of 50% (IRL£4.90) in comparison to those manufactured from normal pork (IRL£9.80). 相似文献
994.
995.
TL Horvath L Roa-Pena RL Jakab ER Simpson F Naftolin 《Canadian Metallurgical Quarterly》1997,61(3-6):349-357
It has been shown that sexual dimorphic morphology of certain hypothalamic and limbic areas underlie gender-specific sexual behavior and neuroendocrine mechanisms. The key role played by locally formed estrogen in these developmental events has been revealed during a critical perinatal period. In this study, we aimed to document the presence of estrogen-synthetase (aromatase)-immunoreactive elements in the involved limbic system and hypothalamus of the developing rat brain. On postnatal day 5, animals of both sexes were perfusion-fixed, and sections from the forebrain and hypothalamus were immunolabelled for aromatase using an antiserum that was generated against a 20 amino acid sequence of placental aromatase. Aromatase-immunoreactivity was present in neuronal perikarya and axonal processes in the following limbic structures: the central and medial nuclei of the amygdala, stria terminalis, bed nucleus of the stria terminalis (BNST), lateral septum, medial septum, diagonal band of Broca, lateral habenula and all areas of the limbic (cingulate) cortex. In the hypothalamus, the most robust labelling was observed in the medial preoptic area, periventricular regions, ventromedial and arcuate nuclei. The most striking feature of the immunostaining with this antiserum was its intracellular distribution. In contrast to the heavy perikaryal labelling that can be observed with most of the currently available aromatase antisera, in the present experiments, immunoperoxidase was predominantly localized to axons and axon terminals. All the regions with fiber staining corresponded to the projection fields of neuron populations that have previously been found to express perikaryal aromatase. Our results confirm the presence of aromatase-immunoreactivity in developing limbic and hypothalamic areas. The massive expression of aromatase in axonal processes raises the possibility that estrogen formed locally by aromatase may not only regulate the growth, pathfinding and target recognition of its host neuronal processes, but may also exert paracrine actions on structures in close proximity, including the target cells. 相似文献
996.
997.
Computational Economics - We develop an agent-based computational model of epidemics with varying amounts of heterogeneity in regional vaccination coverage. We examine the severity of the resulting... 相似文献
998.
Steven A. Mattis Troy Butler 《International journal for numerical methods in engineering》2019,119(10):923-940
Many approaches for solving stochastic inverse problems suffer from both stochastic and deterministic sources of error. The finite number of samples used to construct a solution is a common source of stochastic error. When computational models are expensive to evaluate, surrogate response surfaces are often employed to increase the number of samples available for approximating the solution. This leads to a reduction in finite sampling errors while the deterministic error in the evaluation of each sample is potentially increased. The pointwise accuracy of sampling the surrogate is primarily impacted by two sources of deterministic error: the local order of accuracy in the surrogate and the numerical error from the numerical solution of the model. In this work, we use adjoints to simultaneously give a posteriori error and derivative estimates in order to construct low-order, piecewise-defined surrogates on sets of unstructured samples. Several examples demonstrate the computational gains of this approach in obtaining accurate estimates of probabilities for events in the design space of model input parameters. This lays the groundwork for future studies on goal-oriented adaptive refinement of such surrogates. 相似文献
999.
Miguel A. Santiago Cordoba Jacob S. Spendelow Alario Nicholas G. Parra‐Vasquez Lindsey A. Kuettner Paul M. Welch Christopher E. Hamilton John A. Oertel Juan G. Duque Eric J. Meierdierks Troy A. Semelsberger John C. Gordon Matthew N. Lee 《Advanced functional materials》2020,30(6)
Bijels are used to develop a new class of ultralight hierarchically porous aerogels exhibiting multimodal porosity across multiple length scales. Through in situ functionalization of a particle‐laden liquid interface wherein binary liquid pairs are kinetically trapped out of equilibrium through interfacial jamming, monolithic and freestanding carbon electrodes are produced with prescribed bulk densities down to ≈2 mg cm?3. Exemplary electrokinetic experiments indicate that the bicontinuity of the pore structure is essential for enhancing transport to and from the active electrode surfaces, demonstrating that these materials possess a superior ability to accumulate and transport charge when compared to analogous systems with restricted pore connectivity and fluid throughput. This approach offers a new synthetic route to bicontinuous and hierarchical aerogel materials with nested multimodal porosities. The flexibility of this scheme can address critical issues related to transport‐limited behaviors that arise in many technological fields, ranging from energy and catalysis research to remediation and sensing applications. 相似文献
1000.
Kelly SD Rasbury ET Chattopadhyay S Kropf AJ Kemner KM 《Environmental science & technology》2006,40(7):2262-2268
The mechanism of uranium (U) incorporation into calcite (calcium carbonate) is of fundamental importance to the fate and transport of U at the surface and in the shallow subsurface and has implications for (a) the accuracy of U-Pb and U-series isotope ratio methods used to determine the ages of ancient deposits and (b) potential remediation strategies based on sequestration of U in the subsurface. Extended X-ray absorption fine structure (EXAFS) spectroscopy is uniquely suited to the study of U-calcite systems. The sensitivity of the EXAFS spectrum to the local atomic Ca coordination about U(VI) in the calcite structure results in an increase in the number and amplitude of Ca signals as the U(VI) becomes more ordered within the crystal structure. Our X-ray microprobe (10-microm) measurements of an ancient 298 million-year-old organic-rich calcite (calcrete) clearly revealed three coordination shells of Ca atoms, defining a well-ordered calcite structure about uranyl to a distance of approximately 6.5 angstroms. These results indicate that uranyl is incorporated at the Ca2+ site in calcite and that the uranyl environment may evolve over long time scales, becoming more calcite-like and more stable for long-term sequestration of uranium. These results therefore validate U-related dating methods and show that calcite can be effective at sequestering U in vadose zone sediments. 相似文献