全文获取类型
收费全文 | 1341篇 |
免费 | 4篇 |
专业分类
化学工业 | 40篇 |
金属工艺 | 18篇 |
机械仪表 | 7篇 |
建筑科学 | 1篇 |
矿业工程 | 4篇 |
轻工业 | 5篇 |
石油天然气 | 53篇 |
无线电 | 24篇 |
一般工业技术 | 40篇 |
冶金工业 | 1149篇 |
原子能技术 | 3篇 |
自动化技术 | 1篇 |
出版年
2022年 | 8篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 8篇 |
2013年 | 6篇 |
2012年 | 3篇 |
2011年 | 5篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 6篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 275篇 |
1997年 | 208篇 |
1996年 | 161篇 |
1995年 | 86篇 |
1994年 | 75篇 |
1993年 | 59篇 |
1992年 | 14篇 |
1991年 | 14篇 |
1990年 | 6篇 |
1989年 | 17篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 11篇 |
1981年 | 15篇 |
1980年 | 23篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 75篇 |
1976年 | 125篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1970年 | 2篇 |
1965年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有1345条查询结果,搜索用时 15 毫秒
201.
202.
In Slovenia accurate data on caries trends have not been available. Therefore, in this epidemiological study the caries status of 12-year-old children was compared over time for the years 1970, 1985 and 1991. Each survey comprised examinations of around 150 children of similar socio-economic background, attending the same three schools in Ljubljana. Dental examinations in each survey were carried out by the same examiner. The mean number of decayed, missing and filled teeth (DMFT) decreased from 8.15 in 1970 to 2.96 in 1991 (64%) and the mean number of decayed, missing and filled surfaces (DMFS) decreased from 17.25 in 1970 to 5.11 in 1991 (70%). The mean number of carious surfaces per tooth dropped from 2.12 in 1970 to 1.72 in 1991. The greatest decline occurred on the approximal surfaces (92%), whereas the involvement of occlusal, lingual and buccal surfaces decreased by about 50-60%. The difference between mean DMFT in 1970 and 1985 was statistically significant. Similar differences were found for DMFS (p < 0.05). In the future, a further reduction in caries level may be expected following the introduction of fissure sealing for the preschool and schoolchild population. 相似文献
203.
VK Il''in KG Apostolidi VN Filatov VV Ryl''tsev AA Belov TE Ignatiuk 《Canadian Metallurgical Quarterly》1994,134(2):42-43
In December 1991, an outbreak of Streptococcus bovis septicaemia occurred in a Belgian pigeon loft where 25 male and 25 female racing pigeons were housed. The main clinical signs included inability to fly and poor breeding results. None of the female pigeons and only one male pigeon was able to fly. Nine affected pigeons were necropsied. Histologically a tenosynovitis of the tendon of the deep pectoral muscle was observed in most of them and S bovis was isolated from the canalis triosseus or the shoulder joints of five of the nine pigeons. The pigeons were successfully treated with ampicillin administered in the drinking water for seven days. 相似文献
204.
205.
LL Lukash IS Karpova OS Miroshnichenko TN Tikhonova VV Lylo VG Man'ko EM Sukhorada EL Golynskaia 《Canadian Metallurgical Quarterly》1997,31(5):52-60
Data on separation of purified galactose-specific lectin as well as its two polypeptide chains from inflorescences of European elder Sambucus nigra are represented. Their molecule quaternary structure after the pattern a2 b2 is suggested. It was shown that purified protein in concentration 2.0 mg/ml had mutagenic activity and might enhance mutagenic effect of alkylating substance MNNG. Thus, preparations of lectin from inflorescences of European elder influenced on spontaneous and induced by the alkylating agent mutagenicity in mammalian somatic cells in vitro. 相似文献
206.
207.
SI Leshchuk VV Annenkov VA Kruglova IA Skopintseva 《Canadian Metallurgical Quarterly》1996,41(3):135-137
A possibility of using reversibly sedimented polymeric system for the concentration of hepatitis A and B virus antigen has been demonstrated. As polymeric systems, tetrasole-containing polyelectrolytes and interpolymeric complex polymethacryl acid-poly-1-vinylpyrrolidone were used, capable of sedimenting in acid medium and dissolving in media with the neutral pH. 相似文献
208.
Biologic glue increases capillary ingrowth after cardiomyoplasty in an ischemic cardiomyopathy model
VS Chekanov GV Tchekanov MA Rieder R Eisenstein DM Wankowski DH Schmidt VV Nikolaychik PI Lelkes 《Canadian Metallurgical Quarterly》1996,42(5):M480-M487
The authors investigated the multi-step mechanism of healing after cardiomyoplasty, focusing on the process of angiogenesis. The authors contend that enhancement of angiogenesis and prevention of ischemia-reperfusion injuries immediately after muscle mobilization will be effective in improving cardiomyoplasty results. After cardiomyoplasty, autologous biologic glue (ABG) was administered between the latissimus dorsi muscle (LDM) and myocardium. By 2 months, a new pseudo interlayer was present that bridged the gap between the LDM and myocardium. Neovascularization was visible in the form of numerous small capillaries. Marked degeneration of the LDM was noted, possibly caused by muscle ischemia-reperfusion damage after mobilization. Pockets were created of ischemic and nonischemic LDM to test for angiogenesis. One was left free of ABG (control); one received ABG only; one received ABG and pyrrolostatin. Some of the capillaries were large and had erythrocytes inside. biopsy samples showed 9.4 +/- 1.9% of the sample was occupied by blood vessels (compared with 3.6 +/- 0.7% in control muscle). These preliminary studies prove the feasibility of the authors' concept and provide evidence that angiogenesis can accelerate the healing process and provide an organic bridge between the LDM and myocardium after cardiomyoplasty. 相似文献
209.
VV Mukhin 《Canadian Metallurgical Quarterly》1997,22(1):30-33
Our previous studies have proved that a great number of polymorphonuclear neutrophils (PMN) adhered to endothelial lining and induced endothelial cell (EC) injury. This study was attempted to investigate the change in adhesive force between PMN and EC in response to burn patients' serum within 24 hours and effects of antibody against CD11/CD18 on PMN-EC adhesive force. Burn serum was isolated from 4 burn patients (III degrees 20%-50% TBSA) within 48 hours after burn injury. PMNs were isolated from 8 volunteers. Adhesive force between a PMN and a HUVEC was calculated by means of micropipette technique at 1 h, 3 h, 6 h, 12 h, 24 h after PMN or HUVEC incubated with burn serum or normal serum. Five individual PMN-HUVEC pairs were measured for each sample. All data were analyzed statistically using the t test. RESULTS: 1. The adhesive force between a single PMN-HUVEC pair increased sharply after PMN incubated with burn serum, which reached the maximun level at 1 h after incubation and remained at this level in the following 23 hours. However, the adhesive force was reduced by 78.5%, 72.5%, 75.2% at 1 h, 6 h, 24 h, respectively after the PMNs were pretreated with CD11/CD18 mAb; 2. The adhesive force between a single burn serum stimulated-HUVEC and PMN pair increased gradually, reached peak at 12 h and remained at this level in the following 12 hours. CONCLUSIONS: Burn serum could induce PMN-EC adhesion, with related to PMN aggregation in internal organs and EC damage after burn injury. Antibodies against CD11/CD18 could partially block PMN-EC adhesion and might reduce EC injury induced by activated PMNs. 相似文献
210.
NE Zakharova NP Vaneeva NE Iastrebova NG Kalina MM Tokarskaia VV Sergeev NV Tsvetkova NN Ovechko TV Sokolova 《Canadian Metallurgical Quarterly》1998,(6):82-83
A study was made into the functional status of hypophysis, adrenal cortex, ovaries, and thyroid gland in patients with kraurosis and leukoplakia vulvae. The above patients demonstrated profound disturbances in the system hypophysis-ovaries, that attest to the need for applying corrective therapies to treat the disturbed hormonal homeostasis. 相似文献