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71.
以岗南水库上游流域为研究对象,在岗南水库及其控制流域设置5个采样点位,分析2015年7月至2016年6月流域大气氮素干、湿沉降通量时空分布特征。结果表明,岗南水库流域总氮干、湿沉降通量范围分别为17.7~134.7kg/(km~2·月)和9.9~386.8kg/(km~2·月)。大气干沉降以硝态氮和有机氮为主,春、夏季较高;湿沉降中氮素形态以氨态氮和硝态氮为主,夏季最高,春季次高,秋冬季较低。空间分布上,呈现出由西北向东南不断增加的趋势。利用大气氮素总沉降量、流域面积以及水库水面面积计算得到全流域大气总氮沉降入河负荷量为3 674t/a,直接沉降入库负荷量为105.16t/a。 相似文献
72.
Distinguishing the Chinese materia medica Tiepishihu from similar Dendrobium species of the same genus using histological and microscopic method
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Kun‐Zi Yu Hua Yan Hai‐Chuan Tai Nan‐Ping Zhang Xian‐Long Cheng Zeng‐Xi Guo Shuang‐Cheng Ma Feng Wei 《Microscopy research and technique》2017,80(7):745-755
The Chinese Materia Medica, Tiepishihu, used as a tonic for over one thousand years, is a well‐known precious medicine in China. According to the Chinese Pharmacopoeia, its source is the species Dendrobium officinale Kimura et Migo, which is distinguished from other species in Dendrobium genus. However, these species from the same genus are similar with Tiepishihu and caused confusion in the market. To find a quick and simple method to distinguish Tiepishihu from other similar species, histologic and microscopic methods were combined together to investigate the transverse section of stem of Tiepishihu and other similar species. Phloroglucinol test solution with hydrochloric acid was used to reveal the lignified tissue by staining the transverse section of Tiepishihu and similar species. Results revealed the unique identification characteristics to distinguish Tiepishihu from similar species, which were difficult to distinguish by other methods. The identification characteristics of Tiepishihu include the cells of vascular bundle sheath were stained red, parenchyma cells were not stained red. What's more, other species can be distinguished from each other with microscopic and histological characteristics. These characteristics proved stable and can be easily observed by normal light microscopic examination. This method is rapid, accurate, stable, and inexpensive. 相似文献
73.
响应面法优化虎杖中白藜芦醇提取工艺的研究 总被引:1,自引:0,他引:1
采用响应曲面法并通过单因素试验优化了由纤维素酶酶解提取虎杖中白藜芦醇的条件,所得的最佳工艺为酶用量2mg/g虎杖粉末、温度52.5℃、pH值4.5、酶解时间110min.该条件下每毫升提取液中白藜芦醇的浓度达到了1.489mg/mL,与模型预测值基本相符. 相似文献
74.
The impact of ultrasound on settling in water treatment has been studied. The effects already measured of ultrasound on the settling properties of various effluents have been identified and these effects have been observed in a static and a dynamic study. Sonification conditions suitable for optimizing such a process have been determined. The results show the primary role that stationary wave systems have in the settling of effluents (flocculated or not, synthesized or real). With flocculated effluents, a true impact on settling can be observed. 相似文献
75.
76.
A devolatilization kinetic study of oil coke samples under conditions close to those of industrial calcination furnace is presented. The effects of the surrounding conditions (neutral or oxydizing medium), the heating rate and the percentage of oxygen in an oxydizing environment are analyzed. Experiments are carried out in an induction oven and involved thermogravimetric and chromatographic analyses. Results show that, under certain conditions, the nature of the environment influence the devolatilization process. A slow heating rate and a low content in volatiles promote the coke degradation by oxygen in an oxydizing medium. The reactive schemes are derived by tracking the concentration of CH4, H2, CO and CO2. In regions where the coke is not degraded, a kinetic model is used to compare the parameters describing the develotilization phenomena in the two media (neutral and oxydizing), i.e.: the reaction order, the activation energy and the pre-exponential factor. It is shown that the oxydizing medium promotes an increase in the activation energy. 相似文献
77.
试验结果表明,70%敌溴菊酯乳油2000、3000、4000倍液防治棉叶螨,10天后的防效为90.2~95.2%,显著高于20%双甲脒1500倍液和2.5%溴氰菊酯3000倍液70%的防效,略低于50%克螨特3000倍、15%哒螨灵3000倍、20%三氯杀螨醇1500倍液的防效,但差异不显著。建议生产中敌溴菊酯的使用浓度以3000倍为宜。 相似文献
78.
This paper presents a comparative analysis on leakage losses of a rolling piston type rotary compressor with refrigerants of R290, R22 and R410a. In particular, the difference of leakage losses characteristics between R290 compressor and that of other refrigerant compressors has been studied. Leakage losses through radial clearance, clearances between rolling piston faces and the cylinder head walls, clearances between the sliding vane faces and the cylinder head walls, as well as the clearances between the sides of the sliding vane and the side walls of the chutes inside the cylinder have been studied in the present methodology. Radial leakage caused by the wall velocity has been taken into account in the present study. Simulation results indicate that smaller radial clearance is required for R290 compressor to obtain relatively high efficiency comparing to that of R22 and R410a compressors under the same condition. 相似文献
79.
J.V. Pascual M. Rafecas M.A. Canela J. Boatella R. Bou M.D. Baucells R. Codony 《Food chemistry》2007,102(1):50-58
Here, we study the triacylglycerol (TAG) profile of four different tissues of the pig (backfat, abdominal fat, and muscles trapezius and longissimus thoracis et lumborum). For this purpose, 48 pigs of four breeds (Landrace, Large White, Duroc and a crossbreed Landrace × Duroc) were given one of four diets containing increasing amounts (0%, 2%, 4% and 8%) of a fat blend rich in linoleic acid. The effects of dietary fat and breed on TAG were tested separately for each tissue, and the results are presented using five TAG composition markers, PLL, PStO, PStL, PStSt and OOO. The increasing linoleic acid content provided by diets 1–4 showed a positive effect on the levels of TAG related to this dietary supply (here represented by PLL), and on those of PStL. This increase was at the expense of TAGs containing mainly fatty acids from de novo synthesis (represented by PStO) and in PStSt and OOO. A comparison of the relative % of change for the five selected TAG markers in the distinct tissues indicates that PLL and PStL show much higher increases in muscle than in adipose tissues, whereas PStO and PStSt show similar percentages of decrease in all tissues. OOO showed a higher % of decrease only in trapezius. Results indicate that the breed has a null or scarce effect on the levels of PLL and PStO. For the remaining TAG markers, Large White showed a higher synthesis of saturated TAG (PStSt and PStL) in fat tissues, but not in muscle. Large White also had the lowest levels of OOO in all tissues, being the breed most susceptible to the changes in dietary linoleic acid content. Moreover, the Landrace showed enhanced deposition of monounsaturated TAG in trapezius muscle and abdominal fat. 相似文献
80.
Polyphenol oxidase (PPO) was extracted from bayberry (Myrica rubra Sieb. et Zucc. cv. Biqi), and its partial biochemical characteristics were studied. Stable and highly active PPO extracts were obtained using insoluble polyvinylpolypyrrolidone (PVPP) in sodium phosphate, pH 7.0, buffer. The highest PPO activity was observed in the ripe fruits. Optimum pH and temperature for bayberry PPO activity were pH 6.0 and T = 30 °C with 0.1 M catechol as substrate. PPO showed activity using the substrates of catechol, gallic acid and protocatechuic acid, but no activity with the substrates (+)-catechin, p-coumaric acid or caffeic acid. Km and Vmax values were 313 mM and 3.26ΔOD/min/g FW, respectively, with catechol as the substrate. Bayberry PPO did not act directly on cyanidin 3-glucoside but the rate of anthocyanin degradation was stimulated by the addition of gallic acid. 相似文献