全文获取类型
收费全文 | 17907篇 |
免费 | 793篇 |
国内免费 | 20篇 |
专业分类
电工技术 | 213篇 |
综合类 | 18篇 |
化学工业 | 3675篇 |
金属工艺 | 323篇 |
机械仪表 | 403篇 |
建筑科学 | 1004篇 |
矿业工程 | 49篇 |
能源动力 | 501篇 |
轻工业 | 1675篇 |
水利工程 | 120篇 |
石油天然气 | 56篇 |
武器工业 | 1篇 |
无线电 | 1580篇 |
一般工业技术 | 3054篇 |
冶金工业 | 3019篇 |
原子能技术 | 188篇 |
自动化技术 | 2841篇 |
出版年
2023年 | 140篇 |
2022年 | 226篇 |
2021年 | 457篇 |
2020年 | 341篇 |
2019年 | 366篇 |
2018年 | 424篇 |
2017年 | 388篇 |
2016年 | 491篇 |
2015年 | 423篇 |
2014年 | 520篇 |
2013年 | 1072篇 |
2012年 | 856篇 |
2011年 | 1115篇 |
2010年 | 765篇 |
2009年 | 822篇 |
2008年 | 862篇 |
2007年 | 756篇 |
2006年 | 701篇 |
2005年 | 590篇 |
2004年 | 484篇 |
2003年 | 435篇 |
2002年 | 420篇 |
2001年 | 295篇 |
2000年 | 317篇 |
1999年 | 347篇 |
1998年 | 730篇 |
1997年 | 475篇 |
1996年 | 391篇 |
1995年 | 286篇 |
1994年 | 268篇 |
1993年 | 265篇 |
1992年 | 182篇 |
1991年 | 154篇 |
1990年 | 135篇 |
1989年 | 135篇 |
1988年 | 124篇 |
1987年 | 115篇 |
1986年 | 113篇 |
1985年 | 138篇 |
1984年 | 132篇 |
1983年 | 115篇 |
1982年 | 89篇 |
1981年 | 101篇 |
1980年 | 85篇 |
1979年 | 96篇 |
1978年 | 87篇 |
1977年 | 115篇 |
1976年 | 137篇 |
1975年 | 79篇 |
1974年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
191.
J M Martin A I Mouaddib M Bouzid P Robaux 《Computer methods and programs in biomedicine》1992,39(1-2):35-41
A first software (JHS) for the elaboration of job histories oriented toward risks was designed and results published In an article "A software for the elaboration of Job Histories". This article presents a second software (JES), based on the use of a job-exposure matrix designed for one company. The matrix is essentially a database, an organized gathering of information concerning the company. The two softwares are inter-faced and both run on a PC. When properly exploited, the two softwares can serve as an asset for epidemiological studies dealing with occupational health. 相似文献
192.
193.
194.
195.
Sixty crossbred steers with chronological ages approximating 15 months, carcass weights approximating 270 kg and subcutaneous fat thickness measurements approximating 1·2 cm, were maintained for approximately 210 days on a constantly increasing concentrate ration (13 to 75%, according to NAS nutrient requirements for beef cattle; NAS, 1976). These animals were utilized to evaluate the effects of delayed chilling, hot-boning and electrical stimulation on certain physical, histological, biochemical and sensory properties of three different muscles (Semimembranosus, SM; Longissimus dorsi, LD; and Triceps brachii, TB). Results indicated that neither delayed chilling nor electrical stimulation produced consistent meaningful alterations in any of the physical, cooking or palatability attributes evaluated. However, early post-mortem excision of muscle (hot-boning) consistently produced toughening in all of the muscles evaluated. This was observed to a much greater degree in the TB than in either the SM or LD. Based upon sarcomere length determinations, such toughening could be attributed to cold shortening only in the TB. Electrical stimulation of excised muscle was ineffective in preventing or offsetting this toughening. The delayed chilling treatment imposed (2 h at 12·5°C) was ineffective in enhancing potential effects of electrical stimulation on tenderness. 相似文献
196.
Dalal Bakhos-Douaihy Elie Seaayfan Sylvie Demaretz Martin Komhoff Kamel Laghmani 《International journal of molecular sciences》2021,22(4)
Mutations in the Na-K-2Cl co-transporter NKCC2 lead to type I Bartter syndrome, a life-threatening kidney disease. We previously showed that export from the ER constitutes the limiting step in NKCC2 maturation and cell surface expression. Yet, the molecular mechanisms involved in this process remain obscure. Here, we report the identification of chaperone stress 70 protein (STCH) and the stress-inducible heat shock protein 70 (Hsp70), as two novel binding partners of the ER-resident form of NKCC2. STCH knock-down increased total NKCC2 expression whereas Hsp70 knock-down or its inhibition by YM-01 had the opposite effect. Accordingly, overexpressing of STCH and Hsp70 exerted opposite actions on total protein abundance of NKCC2 and its folding mutants. Cycloheximide chase assay showed that in cells over-expressing STCH, NKCC2 stability and maturation are heavily impaired. In contrast to STCH, Hsp70 co-expression increased NKCC2 maturation. Interestingly, treatment by protein degradation inhibitors revealed that in addition to the proteasome, the ER associated degradation (ERAD) of NKCC2 mediated by STCH, involves also the ER-to-lysosome-associated degradation pathway. In summary, our data are consistent with STCH and Hsp70 having differential and antagonistic effects with regard to NKCC2 biogenesis. These findings may have an impact on our understanding and potential treatment of diseases related to aberrant NKCC2 trafficking and expression. 相似文献
197.
198.
199.
Michael Hausmann Martin Falk Charlotte Neitzel Andreas Hofmann Abin Biswas Theresa Gier Iva Falkova Dieter W. Heermann Georg Hildenbrand 《International journal of molecular sciences》2021,22(7)
In cancer therapy, the application of (fractionated) harsh radiation treatment is state of the art for many types of tumors. However, ionizing radiation is a “double-edged sword”—it can kill the tumor but can also promote the selection of radioresistant tumor cell clones or even initiate carcinogenesis in the normal irradiated tissue. Individualized radiotherapy would reduce these risks and boost the treatment, but its development requires a deep understanding of DNA damage and repair processes and the corresponding control mechanisms. DNA double strand breaks (DSBs) and their repair play a critical role in the cellular response to radiation. In previous years, it has become apparent that, beyond genetic and epigenetic determinants, the structural aspects of damaged chromatin (i.e., not only of DSBs themselves but also of the whole damage-surrounding chromatin domains) form another layer of complex DSB regulation. In the present article, we summarize the application of super-resolution single molecule localization microscopy (SMLM) for investigations of these structural aspects with emphasis on the relationship between the nano-architecture of radiation-induced repair foci (IRIFs), represented here by γH2AX foci, and their chromatin environment. Using irradiated HeLa cell cultures as an example, we show repair-dependent rearrangements of damaged chromatin and analyze the architecture of γH2AX repair clusters according to topological similarities. Although HeLa cells are known to have highly aberrant genomes, the topological similarity of γH2AX was high, indicating a functional, presumptively genome type-independent relevance of structural aspects in DSB repair. Remarkably, nano-scaled chromatin rearrangements during repair depended both on the chromatin domain type and the treatment. Based on these results, we demonstrate how the nano-architecture and topology of IRIFs and chromatin can be determined, point to the methodological relevance of SMLM, and discuss the consequences of the observed phenomena for the DSB repair network regulation or, for instance, radiation treatment outcomes. 相似文献
200.
Kristf Kdr Viktria Juhsz Anna Fldes Rbert Rcz Yan Zhang Heike Lchli Erzsbet Kat Lszl Kles Martin C. Steward Pamela DenBesten Gbor Varga kos Zsembery 《International journal of molecular sciences》2021,22(8)
TRPM7 plays an important role in cellular Ca2+, Zn2+ and Mg2+ homeostasis. TRPM7 channels are abundantly expressed in ameloblasts and, in the absence of TRPM7, dental enamel is hypomineralized. The potential role of TRPM7 channels in Ca2+ transport during amelogenesis was investigated in the HAT-7 rat ameloblast cell line. The cells showed strong TRPM7 mRNA and protein expression. Characteristic TRPM7 transmembrane currents were observed, which increased in the absence of intracellular Mg2+ ([Mg2+]i), were reduced by elevated [Mg2+]i, and were inhibited by the TRPM7 inhibitors NS8593 and FTY720. Mibefradil evoked similar currents, which were suppressed by elevated [Mg2+]i, reducing extracellular pH stimulated transmembrane currents, which were inhibited by FTY720. Naltriben and mibefradil both evoked Ca2+ influx, which was further enhanced by the acidic intracellular conditions. The SOCE inhibitor BTP2 blocked Ca2+ entry induced by naltriben but not by mibefradil. Thus, in HAT-7 cells, TRPM7 may serves both as a potential modulator of Orai-dependent Ca2+ uptake and as an independent Ca2+ entry pathway sensitive to pH. Therefore, TRPM7 may contribute directly to transepithelial Ca2+ transport in amelogenesis. 相似文献