全文获取类型
收费全文 | 4110篇 |
免费 | 216篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 57篇 |
综合类 | 2篇 |
化学工业 | 707篇 |
金属工艺 | 77篇 |
机械仪表 | 52篇 |
建筑科学 | 250篇 |
矿业工程 | 27篇 |
能源动力 | 93篇 |
轻工业 | 479篇 |
水利工程 | 27篇 |
石油天然气 | 18篇 |
无线电 | 339篇 |
一般工业技术 | 675篇 |
冶金工业 | 628篇 |
原子能技术 | 35篇 |
自动化技术 | 863篇 |
出版年
2023年 | 39篇 |
2022年 | 37篇 |
2021年 | 110篇 |
2020年 | 75篇 |
2019年 | 107篇 |
2018年 | 137篇 |
2017年 | 122篇 |
2016年 | 155篇 |
2015年 | 116篇 |
2014年 | 158篇 |
2013年 | 258篇 |
2012年 | 215篇 |
2011年 | 254篇 |
2010年 | 184篇 |
2009年 | 184篇 |
2008年 | 223篇 |
2007年 | 193篇 |
2006年 | 173篇 |
2005年 | 139篇 |
2004年 | 133篇 |
2003年 | 99篇 |
2002年 | 121篇 |
2001年 | 59篇 |
2000年 | 59篇 |
1999年 | 56篇 |
1998年 | 164篇 |
1997年 | 86篇 |
1996年 | 76篇 |
1995年 | 61篇 |
1994年 | 60篇 |
1993年 | 40篇 |
1992年 | 34篇 |
1991年 | 35篇 |
1990年 | 38篇 |
1989年 | 33篇 |
1988年 | 18篇 |
1987年 | 27篇 |
1986年 | 24篇 |
1985年 | 26篇 |
1984年 | 35篇 |
1983年 | 17篇 |
1982年 | 17篇 |
1981年 | 11篇 |
1980年 | 19篇 |
1979年 | 14篇 |
1977年 | 14篇 |
1976年 | 12篇 |
1975年 | 10篇 |
1974年 | 10篇 |
1973年 | 9篇 |
排序方式: 共有4329条查询结果,搜索用时 15 毫秒
1.
2.
Esteban Vera Pingitore María Silvina Juárez Tomás Birgitt Wiese 《Drug development and industrial pharmacy》2015,41(6):942-952
Context: The administration of pharmabiotics is a promising alternative to antimicrobial drugs for the treatment and/or prevention of female urogenital infections.Objective: To design pharmabiotic formulations including bioactive ingredients of microbial origin combined with non-microbial substances and then to evaluate the stability of the combinations during freeze-drying and storage.Materials and methods: Different formulations including Lactobacillus gasseri CRL 1263, Lactobacillus salivarius CRL 1328, salivaricin CRL 1328 (a bacteriocin) and non-microbial compounds (lactose, inulin and ascorbic acid) were assayed, and the ingredients were freeze-dried together or separately. The formulations were stored in gelatin capsules at 4?°C for 360?d.Results: The viability of lactobacilli was affected to different extents depending on the strains and on the formulations assayed. L. salivarius and ascorbic acid were successfully combined only after the freeze-drying process. Salivaricin activity was not detected in formulations containing L. gasseri. However, when combined with ascorbic acid, lactose, inulin or L. salivarius, the bacteriocin maintained its activity for 360?d. The selected microorganisms proved to be compatible for their inclusion in multi-strain formulations together with lactose, inulin and ascorbic acid. Salivaricin could be included only in a L. salivarius CRL 1328 single-strain formulation together with non-microbial substances.Conclusions: This study provides new insights into the design of urogenital pharmabiotics combining beneficial lactobacilli, salivaricin CRL 1328 and compounds with different functionalities. 相似文献
3.
4.
Priyadarshi Chakraborty Yiming Tang Tomoya Yamamoto Yifei Yao Tom Guterman Shai Zilberzwige-Tal Nofar Adadi Wei Ji Tal Dvir Ayyalusamy Ramamoorthy Guanghong Wei Ehud Gazit 《Advanced materials (Deerfield Beach, Fla.)》2020,32(9):1906043
Self-assembled peptide hydrogels represent the realization of peptide nanotechnology into biomedical products. There is a continuous quest to identify the simplest building blocks and optimize their critical gelation concentration (CGC). Herein, a minimalistic, de novo dipeptide, Fmoc-Lys(Fmoc)-Asp, as an hydrogelator with the lowest CGC ever reported, almost fourfold lower as compared to that of a large hexadecapeptide previously described, is reported. The dipeptide self-assembles through an unusual and unprecedented two-step process as elucidated by solid-state NMR and molecular dynamics simulation. The hydrogel is cytocompatible and supports 2D/3D cell growth. Conductive composite gels composed of Fmoc-Lys(Fmoc)-Asp and a conductive polymer exhibit excellent DNA binding. Fmoc-Lys(Fmoc)-Asp exhibits the lowest CGC and highest mechanical properties when compared to a library of dipeptide analogues, thus validating the uniqueness of the molecular design which confers useful properties for various potential applications. 相似文献
5.
6.
Dr. Yahu A. Liu Dr. Qihui Jin Qiang Ding Dr. Xueshi Hao Tingting Mo Shanshan Yan Dr. Yefen Zou Dr. Zhihong Huang Xiaoyue Zhang Wenqi Gao Dr. Tom Y.-H. Wu Chun Li Dr. Badry Bursalaya Dr. Michael Di Donato Dr. You-Qing Zhang Lisa Deaton Dr. Weijun Shen Dr. Brandon Taylor Anwesh Kamireddy Dr. George Harb Dr. Jing Li Dr. Yong Jia Dr. Andrew M. Schumacher Dr. Bryan Laffitte Dr. Richard Glynne Dr. Shifeng Pan Dr. Peter McNamara Dr. Valentina Molteni Dr. Jon Loren 《ChemMedChem》2020,15(16):1562-1570
Loss of β-cell mass and function can lead to insufficient insulin levels and ultimately to hyperglycemia and diabetes mellitus. The mainstream treatment approach involves regulation of insulin levels; however, approaches intended to increase β-cell mass are less developed. Promoting β-cell proliferation with low-molecular-weight inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) offers the potential to treat diabetes with oral therapies by restoring β-cell mass, insulin content and glycemic control. GNF4877, a potent dual inhibitor of DYRK1A and glycogen synthase kinase 3β (GSK3β) was previously reported to induce primary human β-cell proliferation in vitro and in vivo. Herein, we describe the lead optimization that lead to the identification of GNF4877 from an aminopyrazine hit identified in a phenotypic high-throughput screening campaign measuring β-cell proliferation. 相似文献
7.
8.
9.
Somatic hypermutation of the immunoglobulin variable genes during germinal reactions might permit the expansion of B-cell clones with unwanted (e.g. autoreactive) specificity. Here, Ernst Lindhout and colleagues propose three antigen-specific checkpoints that ensure the appropriate antigen specificity of activated B cells is maintained by regulating the activation, selection and further differentiation of B cells. 相似文献
10.
Evaluation of hydroxylapatite/poly(l-lactide) composites: physico-chemical properties 总被引:7,自引:0,他引:7
C. C. P. M. Verheyen C. P. A. T. Klein J. M. A. De Blieck-Hogervorst J. G. C. Wolke C. A. Van Blitterswijn K. De Groot 《Journal of materials science. Materials in medicine》1993,4(1):58-65
The aim of this in vitro study was to examine the physico-chemical behaviour of hydroxylapatite/poly(l-lactide) (HA/PLLA) composites in solution tests. The polymer PLLA, the composites 30 wt% HA/PLLA (C30) and 50 wt% HA/PLLA (C50) and a one-side HA-coated PLLA (HAcP) were evaluated. Rectangular specimens were incubated in various acellular aqueous buffer solutions [citrate, Gomori's and phosphate-buffered saline (PBS)] up to 24 weeks. Data for cumulative release of calcium, phosphate and l-lactate release in solutions containing C30 or C50 showed linear patterns. Release data for solutions containing HAcP combined with scanning micrographs, X-ray microanalysis and X-ray diffraction patterns of the specimens in time showed that the plasma-sprayed HA coating on PLLA dissolves significantly, progressively in the first weeks and almost completely within the tested period of 24 weeks in vitro. A precipitate of scaly crystallites (calcium phosphates) was observed at the HA coating-PBS interface. After 24 weeks incubation all materials were still above their initial weight, indicating that swelling still exceeded dissolution. Application of C30, C50 and HAcP as implant materials seems interesting where initial stabilization through bone bonding is needed or where the linear release of constituents is a requirement. HAcP has the advantage that the HA coating acts as a hydrolysis barrier and consequently delays the degradation of PLLA in vitro. 相似文献