全文获取类型
收费全文 | 2128篇 |
免费 | 86篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 95篇 |
综合类 | 6篇 |
化学工业 | 549篇 |
金属工艺 | 65篇 |
机械仪表 | 43篇 |
建筑科学 | 33篇 |
矿业工程 | 1篇 |
能源动力 | 107篇 |
轻工业 | 140篇 |
水利工程 | 8篇 |
石油天然气 | 3篇 |
无线电 | 187篇 |
一般工业技术 | 456篇 |
冶金工业 | 265篇 |
原子能技术 | 66篇 |
自动化技术 | 193篇 |
出版年
2023年 | 10篇 |
2022年 | 5篇 |
2021年 | 44篇 |
2020年 | 19篇 |
2019年 | 47篇 |
2018年 | 46篇 |
2017年 | 45篇 |
2016年 | 59篇 |
2015年 | 48篇 |
2014年 | 49篇 |
2013年 | 118篇 |
2012年 | 97篇 |
2011年 | 136篇 |
2010年 | 89篇 |
2009年 | 113篇 |
2008年 | 111篇 |
2007年 | 97篇 |
2006年 | 69篇 |
2005年 | 67篇 |
2004年 | 78篇 |
2003年 | 59篇 |
2002年 | 50篇 |
2001年 | 45篇 |
2000年 | 35篇 |
1999年 | 41篇 |
1998年 | 92篇 |
1997年 | 69篇 |
1996年 | 67篇 |
1995年 | 40篇 |
1994年 | 38篇 |
1993年 | 42篇 |
1992年 | 28篇 |
1991年 | 38篇 |
1990年 | 25篇 |
1989年 | 26篇 |
1988年 | 13篇 |
1987年 | 10篇 |
1986年 | 12篇 |
1985年 | 8篇 |
1984年 | 16篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 14篇 |
1980年 | 15篇 |
1979年 | 11篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 14篇 |
1975年 | 6篇 |
1973年 | 6篇 |
排序方式: 共有2217条查询结果,搜索用时 500 毫秒
1.
2.
Masahiro Sato Miyu Koriyama Satoshi Watanabe Masato Ohtsuka Takayuki Sakurai Emi Inada Issei Saitoh Shingo Nakamura Kazuchika Miyoshi 《International journal of molecular sciences》2015,16(8):17838-17856
Some reports demonstrated successful genome editing in pigs by one-step zygote microinjection of mRNA of CRISPR/Cas9-related components. Given the relatively long gestation periods and the high cost of housing, the establishment of a single blastocyst-based assay for rapid optimization of the above system is required. As a proof-of-concept, we attempted to disrupt a gene (GGTA1) encoding the α-1,3-galactosyltransferase that synthesizes the α-Gal epitope using parthenogenetically activated porcine oocytes. The lack of α-Gal epitope expression can be monitored by staining with fluorescently labeled isolectin BS-I-B4 (IB4), which binds specifically to the α-Gal epitope. When oocytes were injected with guide RNA specific to GGTA1 together with enhanced green fluorescent protein (EGFP) and human Cas9 mRNAs, 65% (24/37) of the developing blastocysts exhibited green fluorescence, although almost all (96%, 23/24) showed a mosaic fluorescent pattern. Staining with IB4 revealed that the green fluorescent area often had a reduced binding activity to IB4. Of the 16 samples tested, six (five fluorescent and one non-fluorescent blastocysts) had indel mutations, suggesting a correlation between EGFP expression and mutation induction. Furthermore, it is suggested that zygote microinjection of mRNAs might lead to the production of piglets with cells harboring various mutation types. 相似文献
3.
Tomoya Suzuki Kento Shiota Yu-ichiro Izato Masahiro Komori Koichi Sato Yasuyuki Takai Takayuki Ninomiya Atsumi Miyake 《International Journal of Hydrogen Energy》2021,46(11):8329-8343
Although hydrogen refueling stations (HRSs) are becoming widespread across Japan and are essential for the operation of fuel cell vehicles, they present potential hazards. A large number of accidents such as explosions or fires have been reported, rendering it necessary to conduct a number of qualitative and quantitative risk assessments for HRSs. Current safety codes and technical standards related to Japanese HRSs have been established based on the results of a qualitative risk assessment and quantitative effectiveness validation of safety measures over ten years ago. In the last decade, there has been much development in the technologies of the components or facilities used in domestic HRSs and much operational experience as well as knowledge to use hydrogen in HRSs safely have been gained through years of commercial operation. The purpose of the present study is to conduct a quantitative risk assessment (QRA) of the latest HRS model representing Japanese HRSs with the most current information and to identify the most significant scenarios that pose the greatest risks to the physical surroundings in the HRS model. The results of the QRA show that the risk contours of 10?3 and 10?4 per year were confined within the HRS boundaries, whereas the risk contours of 10?5 and 10?6 per year are still present outside the HRS. Comparing the breakdown of the individual risks (IRs) at the risk ranking points, we conclude that the risk of jet fire demonstrates the highest contribution to the risks at all of the risk ranking points and outside the station. To reduce these risks and confine the risk contour of 10?6 per year within the HRS boundaries, it is necessary to consider risk mitigation measures for jet fires. 相似文献
4.
Although EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is of practical importance because failure to recognize this clinical entity may result in misdiagnosis and subsequent mismanagement of the patients, the pathophysiological nature of EDTA-PTCP remains unknown. To develop an effective way to evaluate the platelet counts in patients with EDTA-PTCP, we introduced aminoglycosides-supplemented anticoagulating agents. When kanamycin was pre-supplemented with EDTA for anticoagulating blood samples from EDTA-PTCP patients there was no significant change in the platelet counts and the morphology of blood cells after 150 min of incubation at room temperature. Furthermore, when kanamycin was added to EDTA-anticoagulated blood samples from EDTA-PTCP patients within 30 min after blood withdrawal, rapid dissociation of platelets without apparent morphological changes of blood cells was observed, and complete blood cell counts as well as the histogram patterns were almost the same as those examined immediately after blood sampling. The dissociation of aggregated platelets was also detected when other antibiotics were used, although it was associated with some extent of morphological changes of blood cells. These findings indicate that the supplementation of aminoglycosides either before or after blood sampling is a useful method for the diagnosis EDTA-PTCP and for the evaluation of platelet counts in patients with EDTA-PTCP. 相似文献
5.
Takayuki Honma Yuichiro Kuroki Tomoichiro Okamoto Masasuke Takata Yukihiro Kanechika Masanobu Azuma Hitofumi Taniguchi 《Ceramics International》2008,34(4):943-946
Aluminum nitride ceramics were prepared by sintering with 0–4.8 mass% of Ca3Al2O6 (C3A) as a sintering additive. The transmittance in the range of 260–550 nm increased with increasing amount of C3A. The cathodoluminescence intensity attributed to oxygen-induced defects decreased with increasing amount of C3A. From the results, the increase of the transmittance in the range of 260–550 nm was considered to be related to the decrease of the oxygen-induced defect density. 相似文献
6.
Segregation of reactive metals at the bonding interface has been observed in various ceramic and/or metal joints bonded with
reactive metal-bearing braze alloys. When a d.c. of 20 mAcm−2 is applied to the ceramic/braze/ceramic system at a brazing temperature of, say, 1373 K, the electric field assists the segregation
at the braze-ceramic interface on the cathode side and suppresses the segregation at the interface on the anode side. This
may imply that reactive metal atoms in the braze can migrate as a cation. E.m.f. measurement on the ceramic (AIN or ZrB2)-metal foil systems with increasing temperature shows that a negative e.m.f. to the ceramic pole appears from about 900 K
for AIN and from 500 K for ZrB2, as does the thermally stimulated current in polymers. These temperatures coincide well with those where the electrical conductivity
of AIN and ZrB2, respectively, begins to increase with increasing temperature. Therefore, it is considered that the polarization of the ceramics
may take place and assist the migration, and consequently segregation, of reactive metals in braze alloys to the braze-ceramic
interface during brazing. 相似文献
7.
F. J. Balta Calleja L. Giri T. Asano T. Mieno A. Sakurai M. Ohnuma C. Sawatari 《Journal of Materials Science》1996,31(19):5153-5157
The microhardness of films of fullerene-polyethylene composites prepared by gelation from semidilute solution, using ultrahigh molecular weight polyethylene (PE) (6×106), has been determined. The composite materials were characterized by optical microscopy and X-ray diffraction techniques. The microhardness of the films is shown to increase notably with the concentration of fullerene particles within the films. In addition, a substantial hardening of the composites is obtained after annealing the materials at high temperatures (T
a=130 °C) and long annealing times (t
a=105s). The hardening of the composites with annealing temperature has been identified with the thickening of the PE crystalline lamellae. Comparison of X-ray scattering data and the microhardness values upon annealing leads to the conclusion of phase separation of C60 molecules from the polyethylene crystals within the material. The temperature dependence is discussed in terms of the independent contribution of the PE matrix of the C60 aggregates to the hardness value. 相似文献
8.
Akihiko Sakurai Mina Masuda Mikio Sakakibara 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2003,78(9):952-958
The removal of phenol by peroxidase‐catalysed polymerization was examined using Coprinus cinereus peroxidase in the presence of surfactants. The non‐ionic surfactants with poly(oxyethene) residues, Triton X‐100, Triton X‐405 and Tween 20, enhanced the phenol removal efficiency at a level similar to high relative molecular mass poly(ethylene glycol) (relative molecular mass 3000). Although the improvement in the removal efficiency was less than that of Triton X‐100, Span 20, sodium lauryl sulfate (SDS) and lauryl trimethylammonium bromide (DTAB) also enhanced the removal efficiency. The requirement of the enzyme for almost 100% removal of 100 mg dm?3 phenol decreased to one‐fourth by the addition of 30 mg dm?3 Triton X‐100. Triton X‐100, Triton X‐405, Tween 20 and DTAB could reactivate the enzyme precipitated with the phenol polymer, leading to the restarting of the phenol removal reaction. Copyright © 2003 Society of Chemical Industry 相似文献
9.
Fatemeh Niyati-Shirkhodaee Takayuki Shibamoto 《Journal of the American Oil Chemists' Society》1992,69(12):1254-1256
Formaldehyde, acrolein, malonaldehyde (MA), acetaldehyde and propanal produced from cod liver oil upon ultraviolet irradiation
(λmax=300 nm) were derivatized into nitrogenor sulfur-containing compounds and then analyzed by capillary gas chromatography with
a nitrogen-phosphorus detector or a flame photometric detector. Acrolein and MA were formed at levels of 10.9±3.06 and 190.2±38.4
nmol/mg of fish oil, respectively. Maximum levels of formaldehyde, acetaldehyde and propanal formed were 7.0±0.90, 49.1±4.5
and 35.8±4.0 nmol/mg of oil, respectively. Formation of propanal in large quantities corresponded to the high content of ɛ-3
fatty acids in cod liver oil. 相似文献
10.
Hara H. Sakurai T. Nagamatsu T. Seta K. Momose H. Niitsu Y. Miyakawa H. Matsuda K. Watanabe Y. Sano F. Chiba A. 《Solid-State Circuits, IEEE Journal of》1992,27(11):1579-1584
BiCMOS standard cell macros, including a 0.5-W 3-ns register file, a 0.6-W 5-ns 32-kbyte cache, a 0.2-W 3-ns table look-aside buffer (TLB), and a 0.1-W 3-ns adder, are designed with a 0.5-μm BiCMOS technology. A supply voltage of 3.3 V is used to achieve low power consumption. Several BiCMOS/CMOS circuits, such as a self-aligned threshold inverter (SATI) sense amplifier and an ECL HIT logic are used to realize high-speed operation at the low supply voltage. The performance of the BiCMOS macros is verified using a fabricated test chip 相似文献