全文获取类型
收费全文 | 5717篇 |
免费 | 131篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 336篇 |
综合类 | 10篇 |
化学工业 | 1167篇 |
金属工艺 | 126篇 |
机械仪表 | 109篇 |
建筑科学 | 94篇 |
矿业工程 | 1篇 |
能源动力 | 164篇 |
轻工业 | 400篇 |
水利工程 | 15篇 |
石油天然气 | 3篇 |
无线电 | 562篇 |
一般工业技术 | 940篇 |
冶金工业 | 1413篇 |
原子能技术 | 149篇 |
自动化技术 | 369篇 |
出版年
2023年 | 26篇 |
2022年 | 52篇 |
2021年 | 84篇 |
2020年 | 37篇 |
2019年 | 61篇 |
2018年 | 60篇 |
2017年 | 39篇 |
2016年 | 63篇 |
2015年 | 70篇 |
2014年 | 89篇 |
2013年 | 217篇 |
2012年 | 174篇 |
2011年 | 235篇 |
2010年 | 196篇 |
2009年 | 189篇 |
2008年 | 207篇 |
2007年 | 195篇 |
2006年 | 189篇 |
2005年 | 146篇 |
2004年 | 152篇 |
2003年 | 169篇 |
2002年 | 130篇 |
2001年 | 135篇 |
2000年 | 123篇 |
1999年 | 186篇 |
1998年 | 563篇 |
1997年 | 381篇 |
1996年 | 272篇 |
1995年 | 160篇 |
1994年 | 149篇 |
1993年 | 140篇 |
1992年 | 88篇 |
1991年 | 69篇 |
1990年 | 71篇 |
1989年 | 70篇 |
1988年 | 64篇 |
1987年 | 41篇 |
1986年 | 62篇 |
1985年 | 51篇 |
1984年 | 54篇 |
1983年 | 40篇 |
1982年 | 51篇 |
1981年 | 38篇 |
1980年 | 39篇 |
1979年 | 34篇 |
1978年 | 26篇 |
1977年 | 34篇 |
1976年 | 45篇 |
1975年 | 18篇 |
1973年 | 23篇 |
排序方式: 共有5858条查询结果,搜索用时 15 毫秒
91.
92.
O van der Heijden HC Chiu TC Park H Takahashi VA LiVolsi JI Risinger JC Barrett A Berchuck AC Evans K Behbakht AW Menzin PC Liu I Benjamin MA Morgan SA King SC Rubin J Boyd 《Canadian Metallurgical Quarterly》1998,23(4):243-247
The degree and nature of patient involvement in consultations with health professionals influences problem and needs recognition and management, and public accountability. This paper suggests a framework for understanding the scope for patient involvement in such consultations. Patients are defined as co-producers of formal health services, whose potential for involvement in consultations depends on their personal rights, responsibilities and preferences. Patients' rights in consultations are poorly defined and, in the National Health Service (NHS), not legally enforceable. The responsibilities of patients are also undefined. I suggest that these are not to deny, of their own volition, the rights of others, which in consultations necessitate mutuality of involvement through information-exchange and shared decision-making. Preferences should be met insofar as they do not militate against responsibilities and rights. 相似文献
93.
D Shiokawa H Ohyama T Yamada K Takahashi S Tanuma 《Canadian Metallurgical Quarterly》1994,226(1):23-30
We studied total occlusion of all three coronary arteries. From 1975 to 1992, a total of 4,100 patients underwent coronary arteriography at Show University Hospital. Of these, four patients (0.1%) had complete occlusion of all three coronary arteries and all of them underwent coronary artery bypass grafting (CABG). The mean numbers of coronary risk factors were only 2.3 but history of angina of effort were long-standing such as 4 to 29 years (mean 16.3 yr). All cases had previous episodes of myocardial infarction. Three cases (75%) had aortic aneurysm. One case was also diagnosed as Leriche syndrome besides coexisting aneurysm. Coronary arteriogram showed total occlusion of right coronary artery, left anterior descending artery and left circumflex artery in the segment of 1.6 or 7 and 11 respectively. All cases had intracoronary anastomosis and intercoronary anastomosis. Among 12 occluded coronary arteries of all four cases, 11 were distally visualized with contrast medium via collateral flow but good opacification of the distal coronary trees were not seen. Also proper assessments of cardiac performance including viability of myocardium were not established because all cases were in the state of C.C.S grades IV. But significant clinical recovery were obtained in all cases after CAGB of three or four bypass. We conclude that these results might be a useful suggestion for the treatment of total occlusion of all three coronary arteries. 相似文献
94.
K Arai S Yamamura T Hanyu HE Takahashi H Umezu H Watanabe T Abo 《Canadian Metallurgical Quarterly》1996,157(11):5170-5177
Murine collagen-induced arthritis (CIA) is known as a T cell-mediated autoimmune disease, although autoantibodies are also suspected to be associated with the onset of the disease. To determine the origin of such T cells in the joints of mice with CIA, their phenotypic properties as well as those of T cells in other immune organs were examined in DBA/1 mice. Since a significant number of mononuclear cells (MNC) was also yielded by the joints of normal DBA/1 mice, the properties of these T cells were examined in parallel. When CIA was induced by an intradermal injection of type II collagen at the base of the tail, the numbers of MNC yielded by the regional lymph nodes and the foot joints were doubled. Interestingly, regardless of the onset of CIA, the joints were always comprised of unique T cell populations, including IL-2(R)alpha- beta+ T cells, gammadelta T cells, CD8alpha+ beta- cells, and CD44+ L-selectin- cells. All these properties coincide with those of extrathymic T cells in liver and intestine. In the case of gammadelta T cells in joints, Vgamma and Vdelta usages were unique and different from those in the other organs. More importantly, Vgamma and Vdelta usages in gammadelta T cells in the joints of normal mice and in those of mice with CIA were essentially the same. Taken together with the expression of recombination-activating gene-1 and -2 mRNAs by MNC in mice with CIA, these findings raise the possibility that the joints have their own resident T cells that are extrathymically generated in situ. 相似文献
95.
M Takahashi F Sasaki T Namieno T Matsuhisa Y Okawa K Taguchi H Takahashi J Uchino 《Canadian Metallurgical Quarterly》1998,13(2-3):191-192
A 3-year child presented with episodic lower abdominal pain; during the eighth attack, a mass was palpable in the left upper quadrant, and a barium enema revealed a stenotic area in the transverse colon. This was resected and an uneventful postoperative course followed. Subsequently, the child has remained symptom-free. instruments are no longer in use. 相似文献
96.
OBJECTIVE: To investigate HLA class II allele associations with autoantibody responses to Ro/SS-A and La/SS-B among Japanese subjects. METHODS: Haplotype and allele distributions, along with molecular polymorphisms, of HLA class II genes were analyzed by polymerase chain reaction-restriction fragment length polymorphism in 41 Japanese women with precipitating autoantibodies to Ro/SS-A and/or La/SS-B. RESULTS: Among women with both Ro/SS-A and La/SS-B antibodies, the HLA class II haplotype DRB1*08032/DQA1*0103/DQB1*0601 and DRB1*08032 allele showed significantly increased frequencies compared with patients with anti-Ro/SS-A alone or with normal controls. All women with both anti-Ro/SS-A and anti-La/SS-B, but not those with anti-Ro/SS-A alone, carried DRB1 alleles that shared the same amino acid residues at positions 14-31 and 71 of the hypervariable regions of the DRB1 chain. All anti-Ro/SS-A positive women carried 1 or 2 alleles of DQB1*06 and DQB1*03 subtypes that shared the same amino acid residues at positions 71-77 of the DQB1 chain. HLA class II allele distributions did not differ among 3 anti-Ro/SS-A positive groups with different disease expressions, i.e., patients with systemic lupus erythematosus, patients with primary Sj?gren's syndrome, and women with no apparent symptoms of rheumatic disease. CONCLUSION: HLA class II allele distributions differ among anti-Ro/SS-A positive subjects according to the presence or absence of coexisting anti-La/SS-B antibodies, but not according to disease expression. Our findings suggest that different HLA class II molecules might control the development of anti-Ro/SS-A and/or anti-La/SS-B antibodies in the autoimmune response to the Ro/SS-A-La/SS-B complex. 相似文献
97.
Y Nakazawa K Mitsui Y Hirai K Takahashi T Ishikawa 《Canadian Metallurgical Quarterly》1994,35(4):197-205
The purpose of this experiment was to investigate histo-pathologically the pulpal reaction to a glass-ionomer/resin (Geristore) restoration system in human teeth. Black's class I cavities were prepared in 22 human teeth; these were divided into 2 groups, one with the Geristore after cavity was cleaned with 10% NaOCl solution and 3% H2O2 solution (Group G) and the other with the Geristore after the cavity was applied with Mirage-Bond (Group MG). The treated teeth were observed clinically over 90 days after operation. They were then extracted for histological examination. No unpleasant symptoms were noted. A few pathological changes were observed. No histo-pathological score differences were observed between groups G and MG. The average evaluation score of pathological results in both groups G and MG were excellent. Microorganisms observed in the cavity dentin of the group G was fewer than in group MG. In some cases, microorganisms were observed along the dentin walls. In conclusion, the pulpal injury due to this Geristore restoration system was slight, and the system was considered to be safe for the pulp and clinically useful. 相似文献
98.
T Ohishi M Takahashi K Kushida H Hoshino T Tsuchikawa K Naitoh T Inoue 《Canadian Metallurgical Quarterly》1998,118(3):126-130
Clinical diagnosis of canine nasal mite (Pneumonyssoides caninum) infection is difficult due to the mite's location in the caudal nasal cavity and frontal sinuses. The current study was performed to evaluate the efficacy of milbemycin oxime in treating dogs with nasal mite infection. A prospective open uncontrolled study included 20 dogs with case histories indicating possible nasal mite infection. Inclusion criteria consisted of either nasal mites being demonstrated (group 1, four dogs), or suspicious clinical signs with no other apparent causes, combined with eosinophilia (group 2, 16 dogs). Milbemycin oxime 1 mg/kg was given orally three times at 10-day intervals. In 17 (85 per cent) dogs, clinical signs resolved completely following milbemycin therapy; within 10 days of the first treatment in 13 cases (group 1, four dogs; group 2, nine dogs) and within 14 days in four cases. In the remaining three dogs clinical signs persisted but were diminished. 相似文献
99.
T Igarashi S Suzuki M Takahashi T Tamaoki T Shimada 《Canadian Metallurgical Quarterly》1998,9(18):2691-2698
Gene transfer into specific tissues or cell types is a key technique in the development of gene therapy. Modification of vector particles such that they selectively bind to the target cells has been attempted, but the limitation of this approach is the low transduction efficiency. Here, we show that a two-step gene transfer system can be used for efficient cell targeting. With this strategy, and using a high-titer adenoviral vector containing a tissue-specific promoter, we have engineered a system in which only target cells become susceptible to retrovirus-mediated transduction. In a model experiment, we constructed an adenoviral vector (Ad.AFPEcoRec) containing the ecotropic retrovirus receptor (EcoRec) gene under the control of the alpha-fetoprotein (AFP) promoter. A binding assay showed that after transduction with AD.AFPEcoRec, EcoRec molecules were efficiently expressed in AFP+HepG2 cells, but not in AFP-HeLa and AFP-HLE cells. The EcoRec-expressing HepG2 cells could be stably transduced with ecotropic retroviral vectors, whereas HeLa and HLE cells remained highly resistant to retrovirus-mediated gene transfer. The apparent titer on HepG2 cells was greater than 2 x 10(5) CFU/ml. Because various tissue-specific promoter/enhancer elements are available, the two-step system could be used as a general strategy for both ex vivo and in vivo targeted gene transfer. 相似文献
100.
Constant stress creep under compression stress, 100 to 316 MPa, at 1100 K was investigated on single-phase TiAl intermetallics. The material was ingot-cast, isothermally forged, and then annealed to produce stable equi-axed grain structures, whose average grain diameters were 25, 42 and 70m. Creep curves were very similar among the three specimens with different grain diameters and the creep rates at a given strain, as well as the minimum creep rates, depended little on grain size. Two regimes were observed on the stress dependence of the minimum creep rate. The stress exponent under high stresses was about 4.5, independent of grain size. Under stresses lower than about 150 MPa it became about 8. 相似文献