全文获取类型
收费全文 | 4546篇 |
免费 | 400篇 |
国内免费 | 1篇 |
出版年
2021年 | 61篇 |
2020年 | 39篇 |
2019年 | 44篇 |
2018年 | 87篇 |
2017年 | 58篇 |
2016年 | 99篇 |
2015年 | 176篇 |
2014年 | 223篇 |
2013年 | 228篇 |
2012年 | 334篇 |
2011年 | 294篇 |
2010年 | 192篇 |
2009年 | 175篇 |
2008年 | 242篇 |
2007年 | 268篇 |
2006年 | 242篇 |
2005年 | 246篇 |
2004年 | 203篇 |
2003年 | 231篇 |
2002年 | 203篇 |
2001年 | 76篇 |
2000年 | 50篇 |
1999年 | 45篇 |
1998年 | 50篇 |
1997年 | 46篇 |
1996年 | 37篇 |
1995年 | 40篇 |
1994年 | 28篇 |
1993年 | 33篇 |
1992年 | 27篇 |
1991年 | 39篇 |
1990年 | 55篇 |
1989年 | 38篇 |
1988年 | 40篇 |
1987年 | 37篇 |
1986年 | 35篇 |
1985年 | 25篇 |
1984年 | 31篇 |
1983年 | 26篇 |
1982年 | 26篇 |
1981年 | 33篇 |
1980年 | 24篇 |
1979年 | 19篇 |
1978年 | 27篇 |
1977年 | 22篇 |
1975年 | 19篇 |
1974年 | 26篇 |
1973年 | 20篇 |
1969年 | 18篇 |
1967年 | 17篇 |
排序方式: 共有4947条查询结果,搜索用时 189 毫秒
151.
Hendrik Schmidt Maxim Bashkuev Marcel Dreischarf Antonius Rohlmann Georg Duda Hans-Joachim Wilke Aboulfazl Shirazi-Adl 《Journal of biomechanics》2013
Anterior shear has been implicated as a risk factor in spinal injuries. A 3D nonlinear poroelastic finite element model study of a lumbar motion segment L4-L5 was performed to predict the temporal shear response under various single and combined shear loads. Effects of nucleotomy and facetectomy as well as changes in the posture and facet gap distance were analyzed as well. 相似文献
152.
Yngve Georg Lithman 《Ethnos》2013,78(3-4):250-265
153.
Rv2140c is one of many conserved Mycobacterium tuberculosis proteins for which no molecular function has been identified. We have determined a high-resolution crystal structure of the Rv2140c gene product, which reveals a dimeric complex that shares strong structural homology with the phosphatidylethanolamine-binding family of proteins. Rv2140c forms low-millimolar interactions with a selection of soluble phosphatidylethanolamine analogs, indicating that it has a role in lipid metabolism. Furthermore, the small molecule locostatin binds to the Rv2140c ligand-binding site and also inhibits the growth of the model organism Mycobacterium smegmatis. 相似文献
154.
Georg Petschenka Steffi Fandrich Nils Sander Vera Wagschal Michael Boppré Susanne Dobler 《Evolution; international journal of organic evolution》2013,67(9):2753-2761
Despite the monarch butterfly (Danaus plexippus) being famous for its adaptations to the defensive traits of its milkweed host plants, little is known about the macroevolution of these traits. Unlike most other animal species, monarchs are largely insensitive to cardenolides, because their target site, the sodium pump (Na+/K+‐ATPase), has evolved amino acid substitutions that reduce cardenolide binding (so‐called target site insensitivity, TSI). Because many, but not all, species of milkweed butterflies (Danaini) are associated with cardenolide‐containing host plants, we analyzed 16 species, representing all phylogenetic lineages of milkweed butterflies, for the occurrence of TSI by sequence analyses of the Na+/K+‐ATPase gene and by enzymatic assays with extracted Na+/K+‐ATPase. Here we report that sensitivity to cardenolides was reduced in a stepwise manner during the macroevolution of milkweed butterflies. Strikingly, not all Danaini typically consuming cardenolides showed TSI, but rather TSI was more strongly associated with sequestration of toxic cardenolides. Thus, the interplay between bottom‐up selection by plant compounds and top‐down selection by natural enemies can explain the evolutionary sequence of adaptations to these toxins. 相似文献
155.
156.
Alexandra Ahlner Mats Carlsson Bengt-Harald Jonsson Patrik Lundström 《Journal of biomolecular NMR》2013,56(3):191-202
We present the software Peak INTegration (PINT), designed to perform integration of peaks in NMR spectra. The program is very simple to run, yet powerful enough to handle complicated spectra. Peaks are integrated by fitting predefined line shapes to experimental data and the fitting can be customized to deal with, for instance, heavily overlapped peaks. The results can be inspected visually, which facilitates systematic optimization of the line shape fitting. Finally, integrated peak volumes can be used to extract parameters such as relaxation rates and information about low populated states. The utility of PINT is demonstrated by applications to the 59 residue SH3 domain of the yeast protein Abp1p and the 289 residue kinase domain of murine EphB2. 相似文献
157.
158.
Jiannong Li Keiryn Bennett Alexey Stukalov Bin Fang Guolin Zhang Takeshi Yoshida Isamu Okamoto Jae‐Young Kim Lanxi Song Yun Bai Xiaoning Qian Bhupendra Rawal Michael Schell Florian Grebien Georg Winter Uwe Rix Steven Eschrich Jacques Colinge John Koomen Giulio Superti‐Furga Eric B Haura 《Molecular systems biology》2013,9(1)
We hypothesized that elucidating the interactome of epidermal growth factor receptor (EGFR) forms that are mutated in lung cancer, via global analysis of protein–protein interactions, phosphorylation, and systematically perturbing the ensuing network nodes, should offer a new, more systems‐level perspective of the molecular etiology. Here, we describe an EGFR interactome of 263 proteins and offer a 14‐protein core network critical to the viability of multiple EGFR‐mutated lung cancer cells. Cells with acquired resistance to EGFR tyrosine kinase inhibitors (TKIs) had differential dependence of the core network proteins based on the underlying molecular mechanisms of resistance. Of the 14 proteins, 9 are shown to be specifically associated with survival of EGFR‐mutated lung cancer cell lines. This included EGFR, GRB2, MK12, SHC1, ARAF, CD11B, ARHG5, GLU2B, and CD11A. With the use of a drug network associated with the core network proteins, we identified two compounds, midostaurin and lestaurtinib, that could overcome drug resistance through direct EGFR inhibition when combined with erlotinib. Our results, enabled by interactome mapping, suggest new targets and combination therapies that could circumvent EGFR TKI resistance. 相似文献
159.
160.
Barbara Thallinger Endry N. Prasetyo Dr. Gibson S. Nyanhongo Georg M. Guebitz 《Biotechnology journal》2013,8(1):97-109
With the increasing prevalence of antibiotic resistance, antimicrobial enzymes aimed at the disruption of bacterial cellular machinery and biofilm formation are under intense investigation. Several enzyme-based products have already been commercialized for application in the healthcare, food and biomedical industries. Successful removal of complex biofilms requires the use of multi-enzyme formulations that contain enzymes capable of degrading microbial DNA, polysaccharides, proteins and quorum-sensing molecules. The inclusion of anti-quorum sensing enzymes prevents biofilm reformation. The development of effective complex enzyme formulations is urgently needed to deal with the problems associated with biofilm formation in manufacturing, environmental protection and healthcare settings. Nevertheless, advances in synthetic biology, enzyme engineering and whole DNA-Sequencing technologies show great potential to facilitate the development of more effective antimicrobial and anti-biofilm enzymes. 相似文献