全文获取类型
收费全文 | 3360篇 |
免费 | 241篇 |
国内免费 | 1篇 |
出版年
2021年 | 25篇 |
2020年 | 22篇 |
2018年 | 27篇 |
2017年 | 24篇 |
2016年 | 51篇 |
2015年 | 101篇 |
2014年 | 129篇 |
2013年 | 119篇 |
2012年 | 150篇 |
2011年 | 122篇 |
2010年 | 108篇 |
2009年 | 73篇 |
2008年 | 120篇 |
2007年 | 99篇 |
2006年 | 132篇 |
2005年 | 115篇 |
2004年 | 106篇 |
2003年 | 107篇 |
2002年 | 87篇 |
2001年 | 58篇 |
2000年 | 76篇 |
1999年 | 67篇 |
1998年 | 28篇 |
1997年 | 30篇 |
1996年 | 38篇 |
1995年 | 24篇 |
1994年 | 27篇 |
1993年 | 28篇 |
1992年 | 44篇 |
1991年 | 50篇 |
1990年 | 51篇 |
1989年 | 49篇 |
1988年 | 29篇 |
1987年 | 35篇 |
1986年 | 30篇 |
1985年 | 65篇 |
1984年 | 70篇 |
1983年 | 52篇 |
1982年 | 107篇 |
1981年 | 105篇 |
1980年 | 93篇 |
1979年 | 119篇 |
1978年 | 82篇 |
1977年 | 60篇 |
1976年 | 33篇 |
1975年 | 24篇 |
1974年 | 41篇 |
1973年 | 24篇 |
1972年 | 23篇 |
1970年 | 25篇 |
排序方式: 共有3602条查询结果,搜索用时 31 毫秒
1.
Ferdinand Bohlmann Elena Tsankova Jasmin Jakupovic Robert M. King Harold Robinson 《Phytochemistry》1983,22(2):557-560
The investigation of Encelia canescens afforded, in addition to several known compounds, four new dimeric p-hydroxyacetophenone derivatives, two epimeric chromene dimers and two epimeric mixed dimers of euparin and encecalin. Furthermore, derivatives of tremetone and of encecalin were present. The structures were elucidated hy high field 1H NMR spectroscopy. 相似文献
2.
The Capricorn silvereye (Zosterops lateralis chlorocephalus) is ideally suited to investigating the genetic basis of body size evolution. We have isolated and characterized a set of microsatellite markers for this species. Seven out of 11 loci were polymorphic. The number of alleles detected ranged from two to five and observed heterozygosities between 0.12 and 0.67. One locus, ZL49, was found to be sex‐linked. This moderate level of diversity is consistent with that expected in an isolated, island population. 相似文献
3.
4.
5.
Brigitta M. N. Brinkman Eric L. Kaijzel Tom W. J. Huizinga Marius J. Giphart Ferdinand C. Breedveld Cornelis L. Verweij 《Human genetics》1995,96(4):493-493
We have identified a C-insertion polymorphism in the 5'UTR of the first exon of the human tumor necrosis factor alpha (TNFA) gene. TNFA is a cytokine that plays an important role in the inflammatory response. 相似文献
6.
7.
Liane Wehder Günther Ernst Anna C. Crecelius Orlando Guntinas-Lichius Christian Melle Ulrich S. Schubert Ferdinand von Eggeling 《The journal of histochemistry and cytochemistry》2010,58(10):929-937
Carcinoma tissue consists of not only tumor cells but also fibroblasts, endothelial cells or vascular structures, and inflammatory cells forming the supportive tumor stroma. Therefore, the spatial distribution of proteins that promote growth and proliferation in these complex functional units is of high interest. Matrix-assisted laser desorption/ionization imaging mass spectrometry is a newly developed technique that generates spatially resolved profiles of protein signals directly from thin tissue sections. Surface-enhanced laser desorption/ionization mass spectrometry (MS)combined with tissue microdissection allows analysis of defined parts of the tissue with a higher sensitivity and a broader mass range. Nevertheless, both MS-based techniques have a limited spatial resolution. IHC is a technique that allows a resolution down to the subcellular level. However, the detection and measurement of a specific protein expression level is possible only by semiquantitative methods. Moreover, prior knowledge about the identity of the proteins of interest is necessary. In this study, we combined all three techniques to gain highest spatial resolution, sensitivity, and quantitative information. We used frozen tissue from head and neck tumors and chose two exemplary proteins (HNP1–3 and S100A8) to highlight the advantages and disadvantages of each technique. It could be shown that the combination of these three techniques results in congruent but also synergetic data. (J Histochem Cytochem 58:929–937, 2010) 相似文献
8.
Groth S.; Mortensen J.; Lange P.; Vest S.; Rossing N.; Swift D. 《Journal of applied physiology》1989,66(6):2750-2755
Pulmonary clearance (PCl) of inhaled aerosolized 99mTc-diethylenetriamine pentaacetic acid (DTPA) across the alveolocapillary membrane is diffusion limited. Therefore, if the mixing of the 99mTc-DTPA in the aqueous hypophase underlying surfactant is slow or incomplete or if there were no hypophase, an increase in the alveolar surface area occupied by 99mTc-DTPA particles would increase the absorption rate. The aim of this study was to examine whether there is an effect on PCl of changing the number of inhaled particles. The change in particle number was accomplished by a setup of four parallel jet nebulizers feeding a central delivery chamber of 400 cm3. We performed two kinds of experiments in eight healthy nonsmokers between 28 and 52 yr of age. In the first experiment, 99mTc-DTPA in saline was nebulized in one nebulizer, while saline was nebulized in the other three. In the second experiment the number of inhaled particles containing 99mTc-DTPA was increased by a factor of four by nebulizing 99mTc-DTPA in saline in all four nebulizers simultaneously. Increasing the number of inhaled 99mTc-DTPA particles caused an increase in PCl of 24.2% (P less than 0.01). We conclude that there is a slight but significant effect of changing the number of DTPA particles on PCl and that this is probably due to an uneven mixing of the 99mTc-DTPA in the aqueous hypophase underlying the surfactant lining and the alveoli. 相似文献
9.
Delivery was induced by an intravenous infusion of prostaglandin F2alpha (PGF2alpha) in gradually increasing doses in 30 consecutive cases of fetal death in utero after the 28th week of gestation. Twenty patients delivered during the first day of prostaglandin administration, 9 on the second day, and 1 patient not until the third day of infusion. It is concluded, that intravenous PGF2alpha appears to be superior to oxytocin in termination of pregnancy under these conditions. 相似文献
10.
Infectivity and effects on host of a long-term stored aqueous suspension of Paranosema locustae on juveniles of Dichroplus maculipennis, a pest grasshopper in parts of the Pampas and Patagonia, were evaluated. Infections developed in 90–97.8% of treated individuals. Mortality increased with time, reaching highest values at 30–40 days post-inoculation (79.5–100%). Infected nymphs showed significantly slower development. 相似文献