全文获取类型
收费全文 | 61878篇 |
免费 | 5456篇 |
国内免费 | 9篇 |
专业分类
67343篇 |
出版年
2023年 | 287篇 |
2021年 | 508篇 |
2020年 | 434篇 |
2019年 | 467篇 |
2018年 | 1083篇 |
2017年 | 1076篇 |
2016年 | 1301篇 |
2015年 | 1436篇 |
2014年 | 1542篇 |
2013年 | 2587篇 |
2012年 | 3902篇 |
2011年 | 4210篇 |
2010年 | 2317篇 |
2009年 | 1663篇 |
2008年 | 3521篇 |
2007年 | 3648篇 |
2006年 | 3386篇 |
2005年 | 3061篇 |
2004年 | 2998篇 |
2003年 | 2730篇 |
2002年 | 2772篇 |
2001年 | 1991篇 |
2000年 | 2157篇 |
1999年 | 1324篇 |
1998年 | 695篇 |
1997年 | 603篇 |
1996年 | 656篇 |
1995年 | 601篇 |
1994年 | 610篇 |
1993年 | 597篇 |
1992年 | 867篇 |
1991年 | 683篇 |
1990年 | 656篇 |
1989年 | 613篇 |
1988年 | 558篇 |
1987年 | 518篇 |
1986年 | 466篇 |
1985年 | 586篇 |
1984年 | 617篇 |
1983年 | 534篇 |
1982年 | 492篇 |
1981年 | 437篇 |
1980年 | 416篇 |
1979年 | 434篇 |
1978年 | 414篇 |
1977年 | 368篇 |
1976年 | 370篇 |
1975年 | 398篇 |
1974年 | 359篇 |
1973年 | 329篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
43.
44.
45.
46.
Sabrina Nickel Farnusch Kaschani Tom Colby Renier A.L. van der Hoorn Markus Kaiser 《Bioorganic & medicinal chemistry》2012,20(2):601-606
Activity-based protein profiling represents a powerful methodology to probe the activity state of enzymes under various physiological conditions. Here we present the development of a para-nitrophenol phosphonate activity-based probe with structural similarities to the potent agrochemical paraoxon. We demonstrate that this probes labels distinct serine hydrolases with the carboxylesterase CXE12 as the predominant target in Arabidopsis thaliana. The designed probe features a distinct labeling pattern and therefore represents a promising chemical tool to investigate physiological roles of selected serine hydrolases such as CXE12 in plant biology. 相似文献
47.
48.
Lymphatic drainage in patients after replantation of extremities 总被引:1,自引:0,他引:1
Lymph drainage was studied by means of lymph scintigraphy in eight patients in whom successful replantation of a totally or subtotally amputated extremity had been performed. Scintigrams were made after subcutaneous injection of technetium-99m in the replanted part of the patient and the contralateral, normal extremity. In all scintigrams, axillary or inguinal lymph node activity is seen, implying drainage of lymph by means of the lymph vessels. Retention of colloid in the replanted part (79 to 94 percent) shows no significant difference with the contralateral, normal side (86 to 94 percent). Unquestionable evidence of regeneration of lymphatics in humans is delivered in the three patients, in whom lymph node activity and normal retention percentages are seen on the scintigrams after total amputation of an extremity followed by replantation without anastomosing of interrupted lymph vessels. 相似文献
49.
A bacterial clone carrying sequences coding for elongation factor EF-1 alpha from Artemia 总被引:2,自引:0,他引:2
A bacterial cDNA clone was identified carrying one third of the nucleotides coding for elongation factor EF-1 alpha from the brine shrimp Artemia. The sequence of codons corresponds with the known sequence of amino acids of EF-1 alpha in the region involved. 相似文献
50.
Peter-Leon Hagedoorn Laura van der Weel Wilfred R. Hagen 《Journal of visualized experiments : JoVE》2014,(93)
Electron Paramagnetic Resonance (EPR) monitored redox titrations are a powerful method to determine the midpoint potential of cofactors in proteins and to identify and quantify the cofactors in their detectable redox state.The technique is complementary to direct electrochemistry (voltammetry) approaches, as it does not offer information on electron transfer rates, but does establish the identity and redox state of the cofactors in the protein under study. The technique is widely applicable to any protein containing an electron paramagnetic resonance (EPR) detectable cofactor.A typical titration requires 2 ml protein with a cofactor concentration in the range of 1-100 µM. The protein is titrated with a chemical reductant (sodium dithionite) or oxidant (potassium ferricyanide) in order to poise the sample at a certain potential. A platinum wire and a Ag/AgCl reference electrode are connected to a voltmeter to measure the potential of the protein solution. A set of 13 different redox mediators is used to equilibrate between the redox cofactors of the protein and the electrodes. Samples are drawn at different potentials and the Electron Paramagnetic Resonance spectra, characteristic for the different redox cofactors in the protein, are measured. The plot of the signal intensity versus the sample potential is analyzed using the Nernst equation in order to determine the midpoint potential of the cofactor. 相似文献