全文获取类型
收费全文 | 2818篇 |
免费 | 203篇 |
出版年
2022年 | 12篇 |
2021年 | 29篇 |
2020年 | 16篇 |
2019年 | 14篇 |
2018年 | 30篇 |
2017年 | 21篇 |
2016年 | 52篇 |
2015年 | 78篇 |
2014年 | 93篇 |
2013年 | 192篇 |
2012年 | 129篇 |
2011年 | 143篇 |
2010年 | 91篇 |
2009年 | 89篇 |
2008年 | 136篇 |
2007年 | 159篇 |
2006年 | 122篇 |
2005年 | 128篇 |
2004年 | 147篇 |
2003年 | 149篇 |
2002年 | 118篇 |
2001年 | 110篇 |
2000年 | 106篇 |
1999年 | 91篇 |
1998年 | 30篇 |
1997年 | 29篇 |
1996年 | 27篇 |
1995年 | 19篇 |
1994年 | 24篇 |
1993年 | 32篇 |
1992年 | 68篇 |
1991年 | 56篇 |
1990年 | 49篇 |
1989年 | 44篇 |
1988年 | 39篇 |
1987年 | 44篇 |
1986年 | 32篇 |
1985年 | 38篇 |
1984年 | 31篇 |
1983年 | 22篇 |
1982年 | 15篇 |
1981年 | 21篇 |
1980年 | 12篇 |
1979年 | 15篇 |
1978年 | 14篇 |
1973年 | 12篇 |
1972年 | 11篇 |
1971年 | 11篇 |
1968年 | 10篇 |
1967年 | 12篇 |
排序方式: 共有3021条查询结果,搜索用时 15 毫秒
991.
The binding of glycol chitin to intact and iodine-inactivated lysozyme was studied by measuring the absorbance of the complex with N-methylnicotinamide chloride, which binds to the subsite C in lysozyme as a competitive inhibitor. The association constant of glycol chitin to inactivated lysozyme was determined from static experiments to be 1.7 × 104M?1. The kinetics of the substrate binding to intact and iodine-inactivated lysozyme were measured by the stopped-flow method at 23°C and pH 5.6. The binding to inactivated lysozyme was clearly monophasic, whereas in intact lysozyme it consisted of multiple phases. In the substrate binding to intact lysozyme, a fast bimolecular process and two subsequent slow unimolecular processes were observed besides the hydrolysis process of polymer substrate. These slow phases were missing completely in inactivated lysozyme. It results from the alteration in the local structure occurring at the subsite D in inactivated lysozyme. These results mean that the slow phases are important for catalytic action of lysozyme. The rate constants of association and dissociation in the fast bimolecular process were determined in this paper. Furthermore, the association constant of the substrate to intact lysozyme was also determined kinetically to be 6.5 × 103M?1. 相似文献
992.
993.
Expression of gastric gland mucous cell-type mucin in normal and neoplastic human tissues. 总被引:5,自引:0,他引:5
Kosei Nakajima Hiroyoshi Ota Mu Xia Zhang Kenji Sano Takayuki Honda Keiko Ishii Jun Nakayama 《The journal of histochemistry and cytochemistry》2003,51(12):1689-1698
Gastric gland mucous cells produce class III mucin, which is also found in Brunner's glands and mucous glands along the pancreaticobiliary tract, and in metaplasia and adenocarcinomas differentiating towards gastric mucosa. Recently, we showed that class III mucin possesses GlcNAcalpha1-->4Galbeta-->R, formed by alpha1,4-N-acetylglucosaminyltransferase (alpha4GnT). Examining the tissue-specific expression of mucin epitopes is useful to clarify cell-lineage differentiation and to identify the site of origin of metastatic carcinomas in histological specimens. Formalin-fixed, paraffin-embedded tissue sections from esophagus, stomach, colon, liver, pancreas, lung, kidney, prostate, breast, and salivary gland resected for carcinoma, as well as salivary gland adenoma, colon adenoma, and metastatic adenocarcinoma of lymph nodes from stomach, pancreas, colon, and breast, were immunostained for MUC6, alpha4GnT, and GlcNAcalpha1-->4Galbeta-->R. These were all expressed in normal, metaplastic, and adenocarcinoma tissues of stomach, pancreas, and bile duct, and in pulmonary mucinous bronchioloalveolar carcinomas. Cells expressing alpha4GnT uniformly expressed GlcNAcalpha1-->4Galbeta-->R. Only MUC6 was expressed in normal salivary glands, pancreas, seminal vesicles, renal tubules, and colon adenomas, and in normal tissue and adenocarcinomas of prostate and breast. No tissues showed immunoreactivity for alpha4GnT alone. Immunohistochemistry (IHC) profiles were similar for metastatic carcinomas and primary carcinoma tissues. The IHC profiles for MUC6, alpha4GnT, and GlcNAcalpha1-->4Galbeta-->R may be diagnostically relevant. 相似文献
994.
Juan Han Hironori Okada Hideki Takai Youhei Nakayama Takahide Maeda Yorimasa Ogata 《Journal of cellular biochemistry》2009,107(6):1198-1204
In this work, we examined the culture condition of alveolar bone marrow multipotent mesenchymal stromal cells (ABMMSCs), aiming to apply regenerative therapy to older periodontitis patients. To better understand the character of cultured cells from alveolar bone marrow, the expression profiles of well‐known genes and their responses to the induction of osteogenic, chondrogenic, or adipogenic differentiation were examined. Using αMEM‐based culture, ABMMSCs could be obtained from older individuals than in previous reports. Interestingly, ABMMSCs expressing Klf4 were able to differentiate into osteoblasts. The prediction of differentiation potential by Klf4 could be a useful guide for further improvement of the culture conditions required to culture ABMMSCs derived from older individuals. J. Cell. Biochem. 107: 1198–1204, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
995.
996.
Motonobu Katoh Yasuhiro Kazuki Kanako Kazuki Naoyo Kajitani Masato Takiguchi Yuji Nakayama Takafumi Nakamura Mitsuo Oshimura 《BMC biotechnology》2010,10(1):37
Background
Microcell-mediated chromosome transfer (MMCT) is a technique by which a chromosome(s) is moved from donor to recipient cells by microcell fusion. Polyethylene glycol (PEG) has conventionally been used as a fusogen, and has been very successful in various genetic studies. However, PEG is not applicable for all types of recipient cells, because of its cell type-dependent toxicity. The cytotoxicity of PEG limits the yield of microcell hybrids to low level (10-6 to 10-5 per recipient cells). To harness the full potential of MMCT, a less toxic and more efficient fusion protocol that can be easily manipulated needs to be developed. 相似文献997.
998.
Effects of abscisic acid on flowering in Pharbitis nil 总被引:1,自引:0,他引:1
Under continuous light, flowering of Pharbitis seedlings wasnot induced by abscisic acid (ABA) treatment. Under short daytreatment, flowering was slightly enhanced by ABA at 0.2 and0.4 mg/liter. Stem elongation was considerably inhibited by25 and 50 mg/liter of ABA irrespective of day length. (Received October 21, 1972; ) 相似文献
999.
Aftab Ahmad Yasuo Niwa Shingo Goto Kyoko Kobayashi Masanori Shimizu Sohei Ito Yumiko Usui Tsutomu Nakayama Hirokazu Kobayashi 《PloS one》2015,10(5)
Salinity represents a major abiotic stress factor that can adversely limit the production, quality and geographical distribution of crops. In this study we focused on dedifferentiated calli with fundamental cell functions, the salt tolerance of which had not been previously examined. The experimental approach was based on activation tagging without regeneration of plants for the identification of salt-tolerant mutants of Arabidopsis. Among 62,000 transformed calli that were screened, 18 potential mutants resistant to 150 mM NaCl were obtained. Thermal asymmetric interlaced (TAIL)-PCR was performed to determine the location of T-DNA integration in the genome. In one line, referred to as salt tolerant callus 1 (stc1), expression of a gene [At4g39800: myo-inositol-1-P-synthase 1 (MIPS1)] was considerably enhanced in calli. Plants regenerated from calli showed tolerance to salt in germination and subsequent growth. Retransformation of wild-type Arabidopsis with MIPS1 conferred salt tolerance, indicating that MIPS1 is the causal gene. The over-expression of MIPS1 increased the content of total inositol. The involvement of MIPS1 in salt tolerance through the fundamental cell growth has been proved in Arabidopsis. 相似文献
1000.
Shinichi Matsuda Kotonari Aoki Takuya Kawamata Tetsuji Kimotsuki Takumi Kobayashi Hiroshi Kuriki Terumi Nakayama Seigo Okugawa Yoshihiko Sugimura Minami Tomita Yoichiro Takahashi 《PloS one》2015,10(5)