全文获取类型
收费全文 | 6269篇 |
免费 | 427篇 |
国内免费 | 292篇 |
出版年
2023年 | 70篇 |
2022年 | 104篇 |
2021年 | 151篇 |
2020年 | 157篇 |
2019年 | 172篇 |
2018年 | 196篇 |
2017年 | 152篇 |
2016年 | 161篇 |
2015年 | 209篇 |
2014年 | 491篇 |
2013年 | 660篇 |
2012年 | 360篇 |
2011年 | 250篇 |
2010年 | 197篇 |
2009年 | 319篇 |
2008年 | 319篇 |
2007年 | 299篇 |
2006年 | 254篇 |
2005年 | 254篇 |
2004年 | 201篇 |
2003年 | 214篇 |
2002年 | 187篇 |
2001年 | 120篇 |
2000年 | 114篇 |
1999年 | 75篇 |
1998年 | 115篇 |
1997年 | 75篇 |
1996年 | 80篇 |
1995年 | 72篇 |
1994年 | 76篇 |
1993年 | 81篇 |
1992年 | 94篇 |
1991年 | 57篇 |
1990年 | 59篇 |
1989年 | 40篇 |
1988年 | 44篇 |
1987年 | 33篇 |
1986年 | 44篇 |
1985年 | 94篇 |
1984年 | 53篇 |
1983年 | 60篇 |
1982年 | 50篇 |
1981年 | 44篇 |
1980年 | 36篇 |
1979年 | 25篇 |
1978年 | 11篇 |
1977年 | 15篇 |
1976年 | 9篇 |
1975年 | 8篇 |
1974年 | 10篇 |
排序方式: 共有6988条查询结果,搜索用时 31 毫秒
1.
Keun-Hong Park 《Biotechnology letters》2002,24(17):1401-1406
A copolymer, including a Gly-Arg-Gly-Asp-Ser (GRGDS) sequence and sugar moieties, was synthesized for the culturing of parenchymal cells (hepatocytes). Hepatocyte cells attached to poly[N-p-vinylbenzyl-d-maltonamide-co-6-(p-vinylbenzamido)-hexanoic acid-GRGDS] [poly(VMA-co-VBRGD)]-coated dishes grew approximately 60% better than on other polymer-coated surface for 12 h. Also, about 80% greater albumin secretion (0.38 pg ml–1) and about 70% greater urea synthesis (0.495 pg ml–1) from hepatocytes were produced in this matrix as compared with unstimulated cells. The behaviour of hepatocytes on poly(VMA-co-VBGRGDS)-coated dishes was not distinct from those attached to a collagen. The conjugation of the adhesion molecules of the RGD peptide in the poly(VMA-co-VBGRGDS) copolymer therefore specifically interacts with integrin families on the hepatocyte cell membrane. 相似文献
2.
Xiao‐Juan Yu Xiao‐Ren Peng Tong‐Huan Li 《Journal of cellular and molecular medicine》2014,18(12):2530-2535
Many studies have examined the association between the FABP2 (rs1799883) Ala54Thr gene polymorphism and type 2 diabetes mellitus risk (T2DM) in various populations, but their results have been inconsistent. To assess this relationship more precisely, A HuGE review and meta‐analysis were performed. The PubMed and CNKI database was searched for case‐control studies published up to April 2014. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Ultimately, 13 studies, comprising 2020 T2DM cases and 2910 controls were included. Overall, for the Thr carriers (Ala/Thr and Thr/Thr) versus the wild‐type homozygotes (Ala/Ala), the pooled OR was 1.18 (95% CI = 1.04–1.34, P = 0.062 for heterogeneity), for Thr/Thr versus Ala/Ala the pooled OR was 1.17 (95% CI = 1.05–1.41 P = 0.087 for heterogeneity). In the stratified analysis by ethnicity, the significantly risks were found among Asians but not Caucasians. This meta‐analysis suggests that the FABP2 (rs1799883) Ala54Thr polymorphisms are associated with increased susceptibility to T2DM risk among Asians but not Caucasians. 相似文献
3.
4.
5.
The biting midge Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae) transmits pathogens to both livestock and wildlife. Biting midge surveillance relies heavily on light traps for collection; however, little is known about the light spectra preferences of C. sonorensis midges. A light assay arena was constructed and light‐emitting diodes (LEDs) of various light spectra were used as light sources to evaluate midge photoattraction. A comparison of responses to light spectra indicated the highest proportions of C. sonorensis were attracted to ultraviolet (UV) light and that midges differentiated 10‐nm differences in wavelength. Stronger intensities of UV light resulted in greater attraction. Midges exhibited both sugar‐seeking and escape behaviours under different conditions of sugar supplementation before and during the experiment. These behaviours occurred with lights of 355 nm and 365 nm in wavelength. Based on the results of this study, the attraction of C. sonorensis to light traps can be improved through the use of bright LEDs at 355 nm or 365 nm. 相似文献
6.
《DNA Repair》2017
Human PrimPol is a recently discovered bifunctional enzyme that displays DNA template-directed primase and polymerase activities. PrimPol has been implicated in nuclear and mitochondrial DNA replication fork progression and restart as well as DNA lesion bypass. Published evidence suggests that PrimPol is a Mn2+-dependent enzyme as it shows significantly improved primase and polymerase activities when binding Mn2+, rather than Mg2+, as a divalent metal ion cofactor. Consistently, our fluorescence anisotropy assays determined that PrimPol binds to a primer/template DNA substrate with affinities of 29 and 979 nM in the presence of Mn2+ and Mg2+, respectively. Our pre-steady-state kinetic analysis revealed that PrimPol incorporates correct dNTPs with 100-fold higher efficiency with Mn2+ than with Mg2+. Notably, the substitution fidelity of PrimPol in the presence of Mn2+ was determined to be in the range of 3.4 × 10−2 to 3.8 × 10−1, indicating that PrimPol is an error-prone polymerase. Furthermore, we kinetically determined the sugar selectivity of PrimPol to be 57–1800 with Mn2+ and 150–4500 with Mg2+, and found that PrimPol was able to incorporate the triphosphates of two anticancer drugs (cytarabine and gemcitabine), but not two antiviral drugs (emtricitabine and lamivudine). 相似文献
7.
8.
F H Stephenson 《Gene》1985,35(3):313-320
9.
10.