全文获取类型
收费全文 | 78137篇 |
免费 | 904篇 |
国内免费 | 1766篇 |
专业分类
电工技术 | 1285篇 |
技术理论 | 2篇 |
综合类 | 658篇 |
化学工业 | 7568篇 |
金属工艺 | 2456篇 |
机械仪表 | 3991篇 |
建筑科学 | 5559篇 |
矿业工程 | 3366篇 |
能源动力 | 521篇 |
轻工业 | 14188篇 |
水利工程 | 2268篇 |
石油天然气 | 1840篇 |
武器工业 | 306篇 |
无线电 | 8095篇 |
一般工业技术 | 21853篇 |
冶金工业 | 1665篇 |
原子能技术 | 667篇 |
自动化技术 | 4519篇 |
出版年
2023年 | 359篇 |
2022年 | 450篇 |
2021年 | 406篇 |
2019年 | 370篇 |
2018年 | 403篇 |
2015年 | 395篇 |
2014年 | 787篇 |
2013年 | 813篇 |
2012年 | 6836篇 |
2011年 | 8475篇 |
2010年 | 2123篇 |
2009年 | 1389篇 |
2008年 | 5937篇 |
2007年 | 5486篇 |
2006年 | 4755篇 |
2005年 | 4357篇 |
2004年 | 3506篇 |
2003年 | 3183篇 |
2002年 | 2857篇 |
2001年 | 2449篇 |
2000年 | 2189篇 |
1999年 | 1368篇 |
1998年 | 871篇 |
1997年 | 830篇 |
1996年 | 790篇 |
1995年 | 762篇 |
1994年 | 767篇 |
1993年 | 559篇 |
1992年 | 773篇 |
1991年 | 795篇 |
1990年 | 834篇 |
1989年 | 801篇 |
1988年 | 798篇 |
1987年 | 972篇 |
1986年 | 914篇 |
1985年 | 908篇 |
1984年 | 890篇 |
1983年 | 801篇 |
1982年 | 875篇 |
1981年 | 825篇 |
1980年 | 643篇 |
1979年 | 456篇 |
1978年 | 342篇 |
1977年 | 335篇 |
1976年 | 406篇 |
1975年 | 381篇 |
1974年 | 383篇 |
1972年 | 316篇 |
1967年 | 373篇 |
1965年 | 401篇 |
排序方式: 共有10000条查询结果,搜索用时 628 毫秒
941.
Straub C Pazdrak K Young TW Stafford SJ Wu Z Wiktorowicz JE Haag AM English RD Soman KV Kurosky A 《Proteomics. Clinical applications》2009,3(10):1151-1173
Eosinophils (EOSs) are granular leukocytes that have significant roles in many inflammatory and immunoregulatory responses, especially asthma and allergic diseases. We have undertaken a fairly comprehensive proteomic analysis of purified peripheral blood EOSs from normal human donors primarily employing 2‐DE with protein spot identification by MALDI‐MS. Protein subfractionation methods employed included IEF (Zoom® Fractionator) and subcellular fractionation using differential protein solubilization. We have identified 3141 proteins, which had Mascot expectation scores of 10?3 or less. Of these 426 were unique and non‐redundant of which 231 were novel proteins not previously reported to occur in EOSs. Ingenuity Pathway Analysis showed that some 70% of the non‐redundant proteins could be subdivided into categories that are clearly related to currently known EOS biological activities. Cytoskeletal and associated proteins predominated among the proteins identified. Extensive protein posttranslational modifications were evident, many of which have not been previously reported that reflected the dynamic character of the EOS. This data set of eosinophilic proteins will prove valuable in comparative studies of disease versus normal states and for studies of gender differences and polymorphic variation among individuals. 相似文献
942.
Giannakis E Samuel CS Hewitson TD Boon WM Macris M Reeve S Lawrence J Ian Smith A Tregear GW Wade JD 《Proteomics. Clinical applications》2009,3(10):1211-1224
Kidney failure is a major health problem worldwide. Patients with end-stage renal disease require intensive medical support by dialysis or kidney transplantation. Current methods for diagnosis of kidney disease are either invasive or insensitive, and renal function may decline by as much as 50% before it can be detected using current techniques. The goal of this study was, therefore, to identify biomarkers of kidney disease (associated with renal fibrosis) that can be used for the development of a non-invasive clinical test for early disease detection. We utilized two protein-profiling technologies (SELDI-TOF MS and 2-D) to screen the plasma and kidney proteome for aberrantly expressed proteins in an experimental mouse model of unilateral uretric obstruction, which mimics the pathology of human renal disease. Several differentially regulated proteins were detected at the plasma level of day-3-obstructed animals, which included serum amyloid A1, fibrinogen α, haptoglobin precursor protein, haptoglobin and major urinary proteins 11 and 8. Differentially expressed proteins detected at the tissue level included ras-like activator protein 2, haptoglobin precursor protein, malate dehydrogenase, α enolase and murine urinary protein (all p<0.05 versus controls). Immunohistochemistry was used to confirm the up-regulation of fibrinogen. Interestingly, these proteins are largely separated into four major classes: (i) acute-phase reactants (ii) cell-signaling molecules (iii) molecules involved in cell growth and metabolism and (iv) urinary proteins. These results provide new insights into the pathology of obstructive nephropathy and may facilitate the development of specific assay(s) to detect and monitor renal fibrosis. 相似文献
943.
Albrethsen J Kaas A Schönle E Swift P Kocova M Gammeltoft S Hansen L Mortensen HB 《Proteomics. Clinical applications》2009,3(3):383-393
Proteomics analysis of serum from patients with type 1 diabetes (T1D) may lead to novel biomarkers for prediction of disease and for patient monitoring. However, the serum proteome is highly sensitive to sample processing and before proteomics biomarker research serum cohorts should preferably be examined for potential bias between sample groups. SELDI‐TOF MS protein profiling was used for preliminary evaluation of a biological‐bank with 766 serum samples from 270 patients with T1D, collected at 18 different paediatric centers representing 15 countries in Europe and Japan over 2 years (2000–2002). Samples collected 1 (n = 270), 6 (n = 248), and 12 (n = 248) months after T1D diagnosis were grouped across centers and compared. The serum protein profiles varied with collection site and day of analysis; however, markers of sample processing were not systematically different between samples collected at different times after diagnosis. Three members of the apolipoprotein family increased with time in patient serum collected 1, 6, and 12 months after diagnosis (ANOVA, p<0.001). These results support the use of this serum cohort for further proteomic studies and illustrate the potential of high‐throughput MALDI/SELDI‐TOF MS protein profiling for evaluation of serum cohorts before proteomics biomarker research. 相似文献
944.
945.
In this study, we describe a phage display strategy to obtain human monoclonal single-chain Fv (scFv) antibodies binding target cancer cell surface proteins. By developing a cancer cell immunization protocol for SCID mice engrafted with human peripheral blood lymphocytes in combination with an antibody phage display method, we have isolated phage antibodies binding small-cell lung cancer cell line H889 by subtractive selection. One of the isolated scFv antibodies, 12EAb, recognized the E2 component of pyruvate dehydrogenase complex (PDC-E2) by immunoprecipitation according to MALDI-TOF MS analysis. Furthermore, we have confirmed the plasma membrane localization of PDC-E2 in small-cell lung cancer cells by immunocytochemistry and cell surface protein biotinylation, although PDC-E2 is usually located in the mitochondrial matrix. These results, including unique localization of identified antigens, were obtained by proteomic approaches. The present methods can be applied to generate human monoclonal scFv antibodies against tumor cells and to identify new molecular targets for immunotherapy and markers for diagnosis. 相似文献
946.
Although experiments in rodents and human population-based studies have demonstrated the efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) such as sulindac in colorectal cancer (CRC) prevention, a detailed knowledge of the underlying mechanism of action of this drug is limited. To better understand the chemopreventitive effects of sulindac, especially early sulindac-induced apoptotic events, we used the CRC cell line LIM1215 as an experimental model, focusing on proteins secreted into the LIM1215 culture medium - i.e., the secretome. This subproteome comprises both soluble-secreted proteins and exosomes (30-100?nm diameter membrane vesicles released by several cell types). Selected secretome proteins whose expression levels were dysregulated by 1?mM sulindac treatment over 16?h were analyzed using 2-D DIGE, cytokine array, Western blotting, and MS. Overall, 150 secreted proteins were identified, many of which are implicated in molecular and cellular functions such as cell proliferation, differentiation, adhesion, invasion, angiogenesis, metastasis, and apoptosis. Our secretome-based proteomic studies have identified several secreted modulators of sulindac-induced apoptosis action (e.g., Mac-2 binding protein, Alix, 14-3-3 isoforms, profilin-1, calumenin/Cab45 precursors, and the angiogenic/tumor growth factors interleukin 8 (IL-8) and growth related oncogene (GRO-α)) that are likely to improve our understanding of the chemopreventitive action of this NSAID in CRC. 相似文献
947.
数据仓库与一般数据库项目不同。总是处于不断变化的状态中。创建一个数据仓库并非一项简单的任务。它融合了商务系统的最佳策略和信息系统的最佳技术。需要进行精细的设计和规划。作者介绍了她设计的数据库生命周期管理方法。面向不是项目经理的参与人员。详细描述了数据仓库项目开发的全过程。 相似文献
948.
Currently, the rotational speed of spindle motors in HDDs (Hard-Disk Drives) are increasing to improve high data throughput and decrease rotational latency for ultra-high data transfer rates. However, the disk platters are excited to vibrate at their natural frequencies due to higher air-flow excitation as well as eccentricities and imbalances in the disk-spindle assembly. These factors contribute directly to TMR (Track Mis-Registration) which limits achievable high recording density essential for future mobile HDDs. In this paper, the natural mode shapes of an annular disk mounted on a spindle motor used in current HDDs are characterized using FEM (Finite Element Methods) analysis and verified with SLDV (Scanning Laser Doppler Vibrometer) measurements. The identified vibration frequencies and amplitudes of the disk ODS (Operating Deflection Shapes) at corresponding disk mode shapes are modelled as repeatable disturbance components for servo compensation in HDDs. Our experimental results show that the SLDV measurements are accurate in capturing static disk mode shapes without the need for intricate air-flow aero-elastic models, and the proposed disk ODS vibration model correlates well with experimental measurements from a LDV. 相似文献
949.
950.
Mancić A Fuchs J Antici P Gaillard SA Audebert P 《The Review of scientific instruments》2008,79(7):073301
In this paper, the absolute calibration of photostimulable image plates (IPs) used as proton detectors is presented. The calibration is performed in a wide range of proton energies (0.5-20 MeV) by exposing simultaneously the IP and calibrated detectors (radiochromic films and solid state detector CR39) to a source of broadband laser-accelerated protons, which are spectrally resolved. The final result is a calibration curve that enables retrieving the proton number from the IP signal. 相似文献