全文获取类型
收费全文 | 9606篇 |
免费 | 576篇 |
国内免费 | 2篇 |
出版年
2022年 | 36篇 |
2021年 | 121篇 |
2020年 | 73篇 |
2019年 | 82篇 |
2018年 | 144篇 |
2017年 | 108篇 |
2016年 | 199篇 |
2015年 | 289篇 |
2014年 | 351篇 |
2013年 | 640篇 |
2012年 | 567篇 |
2011年 | 572篇 |
2010年 | 365篇 |
2009年 | 354篇 |
2008年 | 613篇 |
2007年 | 563篇 |
2006年 | 541篇 |
2005年 | 574篇 |
2004年 | 586篇 |
2003年 | 546篇 |
2002年 | 484篇 |
2001年 | 190篇 |
2000年 | 167篇 |
1999年 | 173篇 |
1998年 | 126篇 |
1997年 | 105篇 |
1996年 | 84篇 |
1995年 | 105篇 |
1994年 | 81篇 |
1993年 | 73篇 |
1992年 | 135篇 |
1991年 | 87篇 |
1990年 | 92篇 |
1989年 | 87篇 |
1988年 | 80篇 |
1987年 | 84篇 |
1986年 | 66篇 |
1985年 | 62篇 |
1984年 | 53篇 |
1983年 | 50篇 |
1982年 | 56篇 |
1981年 | 48篇 |
1980年 | 30篇 |
1979年 | 39篇 |
1978年 | 38篇 |
1977年 | 33篇 |
1976年 | 29篇 |
1975年 | 33篇 |
1973年 | 22篇 |
1970年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
A simple and yet reliable silver impregnation method, using potassium ferrocyanide, for demonstrating nervous tissue of the rat central nervous system embedded in paraffin or paraplast is described. The method reported here is compared and discussed with earlier techniques using potassium dicyanoargentate, potassium ferrocyanide and potassium ferricyanide. 相似文献
3.
4.
Yusuke Nakamura Michio Ogawa Takahiro Nishide Mitsuru Emi Goro Kosaki Seiichi Himeno Kenichi Matsubara 《Gene》1984,28(2):263-270
The nucleotide sequences of the cloned human salivary and pancreatic α-amylase cDNAs correspond to the continuous mRNA sequences of 1768 and 1566 nucleotides, respectively. These include all of the amino acid coding regions. Salivary cDNA contains 200 bp in the 5′-noncoding region and 32 in the 3′-noncoding region. Pancreatic cDNA contains 3 and 27 bp of 5′- and 3′-noncoding regions, respectively. The nucleotide sequence humology of the two cDNAs is 96% in the coding region, and the predicted amino acid sequences are 94% homologous.Comparison of the sequences of human α-amylase cDNAs with those previously obtained for mouse α-amylase genes (Hagenbuchle et al., 1980; Schibler et al., 1982) showed the possibility of gene conversion between the two genes of human α-amylase. 相似文献
5.
S Ikei M Ogawa T Beppu C Ohara K Sakamoto H Sameshima H Arakawa Y Yamaguchi T Yamanaka S Kudo 《Cytokine》1992,4(6):581-584
In an attempt to investigate the interaction between the changes of cytokines and acute phase reactants after transcatheter arterial chemoembolization therapy (TACE), the levels of interleukin 6 (IL-6), interleukin 8 (IL-8), C-reactive protein (CRP) and pancreatic secretory trypsin inhibitor (PSTI) in the blood of patients with unresectable hepatocellular carcinoma (HCC) were measured. Before the therapy, serum IL-6 and plasma IL-8 levels were detectable in 77.8% and 28.5%, respectively, of patients with HCC. Levels of serum IL-6 and plasma IL-8 increased after TACE and reached a peak on day 3 in all patients (18/18) and in 87.5% of patients (12/14), respectively. Both blood levels of IL-6 and IL-8 reached a peak earlier than those of CRP and PSTI did after the therapy. When the maximal values of IL-6 were compared with those of CRP and PSTI, there were significant positive correlations (r = 0.63, P < 0.01 and r = 0.81, P < 0.01, respectively). Similarly, comparisons of the maximal values of IL-8 with those of CRP and PSTI gave a significant correlation (r = 0.68, P < 0.01 and r = 0.67, P < 0.05, respectively). However, no significant correlation was found between the elevation of IL-6 and IL-8. 相似文献
6.
7.
Conformation of the glucotriose unit in the lipid-linked oligosaccharide precursor for protein glycosylation. 总被引:1,自引:0,他引:1
The conformation of the glucotriose unit of the protein glycosylation precursor Glc3Man9GlcNAc2 was assessed by deuterium exchange studies on the model tetrasaccharide alpha Glc----2 alpha Glc----3 alpha Glc----3 alpha Man----OCH2CH2CH3 dissolved in deuterated dimethyl sulfoxide. The hydroxyl proton on C-2 of the nonreducing end glucose and on C-4 of the glucose attached to mannose both show dramatic isotope shifts indicative of a strong hydrogen bond between these two hydroxyl groups. Such a hydrogen bond requires a fixed conformation of the glucotriose unit that brings these hydroxyl groups within 3 A of each other, a conformation that is supported by molecular modeling based on hard-sphere exo-anomeric (HSEA) calculations. The temperature dependence of the hydroxyl proton chemical shifts supports the postulated hydrogen bond, and the torsional angles between the three glucose units derived from the HSEA calculations are consistent with results from related studies on other saccharides. The results support a model for biochemical function in which the glucotriose unit could modulate the activity of the oligosaccharyltransferase by binding in a fixed conformation to a specific effector site in the enzyme. 相似文献
8.
Ishida Takuya Uehara Yoshitoshi Ikeya Tohru Haraguchi Takashi F. Asano Satoshi Ogino Yohei Okuda Noboru 《Limnology》2020,21(3):403-413
Limnology - Controlling phosphorous (P) loads from rice fields is important for the conservation of aquatic ecosystems, in part because P is relatively concentrated at its sources. Recently, winter... 相似文献
9.
Satoshi Shizukuishi Satoshi Nishii John Ellis Karl Folkers 《Biochemical and biophysical research communications》1980,95(3):1126-1130
The mean basal specific activities and the mean % deficiencies of the activity of the glutamic oxaloacetic transaminase of the erythrocytes were identical (n.s.) for a group of eight patients with a severe carpal tunnel syndrome and for a group of eight university students. There was no significant difference in the increases in the specific activities for the patients and the students at 4 concentrations of pyridoxal 5′-phosphate. The apparent Km for the patients and the students was 95 μM and 61 μM (n.s.) respectively. It is concluded from these data in conjunction with previous findings that the carpal tunnel syndrome is a deficiency disease of vitamin B6, which is probably primary rather than one of a dependency state. 相似文献