全文获取类型
收费全文 | 799篇 |
免费 | 25篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 11篇 |
化学工业 | 165篇 |
金属工艺 | 22篇 |
机械仪表 | 27篇 |
建筑科学 | 13篇 |
能源动力 | 24篇 |
轻工业 | 86篇 |
水利工程 | 2篇 |
无线电 | 135篇 |
一般工业技术 | 171篇 |
冶金工业 | 74篇 |
自动化技术 | 98篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 14篇 |
2021年 | 13篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 13篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 15篇 |
2013年 | 60篇 |
2012年 | 35篇 |
2011年 | 33篇 |
2010年 | 33篇 |
2009年 | 38篇 |
2008年 | 46篇 |
2007年 | 57篇 |
2006年 | 38篇 |
2005年 | 28篇 |
2004年 | 21篇 |
2003年 | 29篇 |
2002年 | 27篇 |
2001年 | 18篇 |
2000年 | 19篇 |
1999年 | 21篇 |
1998年 | 36篇 |
1997年 | 29篇 |
1996年 | 29篇 |
1995年 | 19篇 |
1994年 | 18篇 |
1993年 | 14篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1977年 | 5篇 |
1976年 | 3篇 |
排序方式: 共有828条查询结果,搜索用时 31 毫秒
91.
A sensitive reversed-phase high-performance liquid chromatographic method with ultraviolet detection was developed for the analysis of a new angiotensin II receptor antagonist, DuP 532 (L-694,492), in human plasma and urine. The analyte and internal standard are extracted from plasma and urine at a pH between 3.3 to 3.6 by liquid-liquid extraction and analyzed on a C6 column with ultraviolet detection at 254 nm. The mobile phase is composed of acetonitrile and phosphate buffer at pH 2.5. The limits of quantification are 6 and 7.5 ng/ml for plasma and urine, respectively. 相似文献
92.
Yih-Peng Chiou Hung-Chun Chang 《Photonics Technology Letters, IEEE》1998,10(7):976-978
The recently proposed complementary operators method (COM) is applied to the beam propagation method (BPM). The spurious reflection using the COM can be several orders lower than that using other boundary conditions 相似文献
93.
Dr Jau-Woie Chang Shean-Shyong Chiou Yih-Ping Luh 《The International Journal of Advanced Manufacturing Technology》1997,13(6):434-442
This paper deals with the function modules demanded for production control in a distributed cellular manufacturing system. Cells are the distributed components of any manufacturing system. A proposed multipassing distributed simulating scheduling system (MPDSSS) deals with the production control functions regarding process planning (working-cell selection), scheduling, rescheduling, and real-time dispatching. The process planning function aims at selecting a good route for each job. The multipassing scheduling aims at providing a scheduling bidding strategy in a distributed fashion. The rescheduling aims at dealing with the large-effort change of the system with updating the precedence schedule to run in a new manufacturing period. The real-time scheduling deals with the small-effort change of the system with a real-time dispatching rule. All the production controlling functions have been implemented in distributed fashions. A simulation experiment demonstrates that the proposed MPDSSS leads to good results in the following criteria: minimum mean flow time, minimum waiting time, maximum machine utilisation, and minimum imbalance of cell utilisation.Nomenclature {A}
grouping set ofA
i
-
A
i
function-identical set of celli
- BC
i
the weighted bidding cost for the operation in celli
- {C}
performance criteria set
-
C
i
ith element of {C}
- CU
f avg
average cell utilisation inA
f
- CU
f max
maximum cell utilisation inA
f
- CU
i
average cell utilisation of celli
- CUmax
maximum CU
i
- CUmin
minimum CU
i
- {D}
dispatching rule base
-
D
i
ith rule in {D}
- EFT
earliest finishing time
- EFTmax
maximum EFT
- ICU
f
the imbalance of cell utilisation inA
f
- P
m
previously actual system performance for criterionC
m
- RC
i
rescheduling cost when using ruleD
i
- SC
i
improvement rate for system cost using ruleD
i
- SP
a
actual system performance
- SP
m
preceding simulation performance of theC
m
with ruleD
i
- SP
p
ideally predictable system performance
- SPD
a
actual system performance deviation
- TICU
i
total imbalance of cell utilisation using ruleD
i
-
W
weighting factor 相似文献
94.
Hsien-Chin Chiu Shih-Cheng Yang Cheng-Kuo Lin Ming-Jyh Hwu Chiou H.K. Yi-Jen Chan 《Electron Device Letters, IEEE》2004,25(5):253-255
A K-band (20 GHz) monolithic amplifier was developed and fabricated by adopting a low-/spl kappa/ benzocyclobutene (BCB) coplanar waveguide (CPW) line and InGaP-InGaAs doped-channel HFETs (DCFETs). This monolithic microwave integrated circuit (MMIC) utilizes a high impedance BCB CPW microstrip line (Z/sub 0/=70 /spl Omega/) for the biasing circuits, and a Z/sub 0/=50 /spl Omega/ line for the RF signal transmission. The low dielectric constant characteristic of the BCB interlayer is beneficial for a common-ground bridge process, which reduces the parasitics. The calculated loss tan/spl delta/ is 0.036 for the BCB at 20 GHz. The one-stage MMIC amplifier achieves an S/sub 21/ of 5 dB at 20 GHz, which is the first demonstration of the K-band InGaP-InGaAs DCFET monolithic circuit. 相似文献
95.
Nonstoichiometric BaTiO3 PTCR type materials are investigated with various amounts of MnO2, Sb2O3 and MgO dopants. Specimens fired with a nonisothermal rate-controlled sintering profile exhibit a rather fine and uniform microstructure as compared to those processed by conventional sintering techniques. The temperature at which the resistivity anomaly begins is observed to decrease with Sb2O3 and MgO contents. The Curie point of BaTiO3-based ceramics can be altered by addition of Sb2O3, and the dielectric peak is maintained by the presence of MgO additive. Magnesium ions act as acceptors in the BaTiO2 lattice, while antimony ions as donors. The presence of magnesium compensates some of the antimony, hence the doped-BaTiO3 seminonductive region is pushed to higher contents. 相似文献
96.
97.
Wu TH Teslaa T Kalim S French CT Moghadam S Wall R Miller JF Witte ON Teitell MA Chiou PY 《Analytical chemistry》2011,83(4):1321-1327
It is difficult to achieve controlled cutting of elastic, mechanically fragile, and rapidly resealing mammalian cell membranes. Here, we report a photothermal nanoblade that utilizes a metallic nanostructure to harvest short laser pulse energy and convert it into a highly localized explosive vapor bubble, which rapidly punctures a lightly contacting cell membrane via high-speed fluidic flows and induced transient shear stress. The cavitation bubble pattern is controlled by the metallic structure configuration and laser pulse duration and energy. Integration of the metallic nanostructure with a micropipet, the nanoblade generates a micrometer-sized membrane access port for delivering highly concentrated cargo (5 × 10(8) live bacteria/mL) with high efficiency (46%) and cell viability (>90%) into mammalian cells. Additional biologic and inanimate cargo over 3-orders of magnitude in size including DNA, RNA, 200 nm polystyrene beads, to 2 μm bacteria have also been delivered into multiple mammalian cell types. Overall, the photothermal nanoblade is a new approach for delivering difficult cargo into mammalian cells. 相似文献
98.
Nikolaos K. Andrikopoulos Antonia Chiou Anastasia Mylona 《Food Reviews International》2004,20(4):389-405
Chromatographic and spectroscopic methods used for the detection and quantification of triacylglycerol (TAG) species present in less common edible vegetable oils (almond, hazelnut, pumpkin seed, safflower, sesame, walnut, and wheatgerm oils) are reviewed. For these oils, as well as for thistle oil and high-oleic sunflower oil, for which no data exist on their TAG composition, both high-performance liquid chromatography (HPLC) and gas chromatography (GC) chromatographic plus spectrometric techniques have also been performed. Triacylglycerol comparison of the data found in the literature is also presented. Five fatty acyl moieties (palmitoyl-, stearoyl-, oleoyl-, linoleoyl-, and linolenoyl-) are found to mainly contribute to the formation of TAG species of the aforementioned edible vegetable oils, whereas six more (palmitoleoyl-, arachidoyl-, gadoleoyl-, heptadecenoyl-, margaroyl-, and erucoyl-) are reported as minors. Only 19 to 33 TAG make up the mass of these oils. These TAG are also found in most common edible oils, thus indicating a “uniformity” in the minor and main TAG composition of edible vegetable oils. Trioleoyl-glycerol predominates in almond (13.3-48.6%), hazelnut (35.3-57.9%), and high oleic sunflower (44.2% and 52.9%) oils, trilinoleoyl-glycerol in safflower (40.1-49.7%), thistle (36.9% and 46.0%), walnut (25.9-38.1%), and wheatgerm (15.7-33.0%) oils. Sesame and pumpkin seed oils are rich in dioleoyl-linoleoyl-glycerol (5.9-17.5%, 9.5% and 18.6%, respectively) and oleoyl-dilinoleoyl-glycerol (8.0-18.7% and 12.8-21.1%, respectively). 相似文献
99.
100.
AG Chiou GJ Florakis RL Copeland VA Williams SA McCormick R Chiesa 《Canadian Metallurgical Quarterly》1998,17(5):566-570
Endoscopic treatment of chronic pancreatitis has drawn benefits from endoscopic procedures previously described for the main bile duct. Endotherapy is developing throughout the world. Cyst drainage procedures certainly represent the largest step forward in that non-surgical approach, whatever it is either direct (through the stomach or the duodenum) or indirect through the papilla in the duodenum. This procedure gives similar results to surgery with a lower morbidity. Pancreatic duct drainage associated with stone clearance is feasible and provides good results which have not yet been compared with those obtained thanks to surgery. Nonetheless, when the duct is not widely dilated it has been proven to be a satisfactory alternative to surgery. By contrast, chronic cholestasis does not appear to be a good indication of endotherapy. 相似文献