全文获取类型
收费全文 | 1273篇 |
免费 | 64篇 |
国内免费 | 1篇 |
出版年
2019年 | 6篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 27篇 |
2014年 | 35篇 |
2013年 | 117篇 |
2012年 | 59篇 |
2011年 | 63篇 |
2010年 | 32篇 |
2009年 | 31篇 |
2008年 | 65篇 |
2007年 | 73篇 |
2006年 | 69篇 |
2005年 | 59篇 |
2004年 | 71篇 |
2003年 | 67篇 |
2002年 | 69篇 |
2001年 | 28篇 |
2000年 | 24篇 |
1999年 | 26篇 |
1998年 | 17篇 |
1997年 | 12篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 20篇 |
1991年 | 20篇 |
1990年 | 16篇 |
1989年 | 33篇 |
1988年 | 21篇 |
1987年 | 23篇 |
1986年 | 19篇 |
1985年 | 13篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 11篇 |
1978年 | 4篇 |
1977年 | 13篇 |
1976年 | 12篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 7篇 |
1972年 | 7篇 |
1971年 | 8篇 |
1970年 | 10篇 |
排序方式: 共有1338条查询结果,搜索用时 15 毫秒
1.
2.
Munirul Alam Shin-ichi Miyoshi Ikuyo Maruo Chiemi Ogawa Sumio Shinoda 《Microbiology and immunology》1994,38(6):467-470
The protease elaborated by Vibrio mimicus is known to possess hemagglutinating ability to chicken erythrocytes, the well-known HA/protease. A non-protease hemagglutinin (HA) with strong agglutinating ability towards rabbit erythrocytes was obtained from 32 hr culture supernatant of a pathogenic environmental strain of V. mimicus. This HA (V. mimicus HA: VMHA) appeared stable at relatively higher temperature and agglutinated the erythrocytes from rabbit, guinea pig and mouse but not the erythrocytes from chicken, bovine, horse and sheep. Simple sugars, metal ions and chelating agents failed to inhibit the activity of VMHA. The activity of VMHA was found to be sensitive to digestion by proteolytic enzymes including HA/protease. These results provide evidence for the existence of novel HA other than HA/protease in V. mimicus. 相似文献
3.
A rat adrenal cDNA library was screened by colony hybridization using a rat cDNA fragment of type I angiotensin II receptor (AT1A) previously isolated from the kidney. Two cDNA clones were identified, designated as AT1B, to have a nucleotide sequence highly homologous to and yet distinct from AT1A. The amino acid sequence of AT1B consists of 359 amino acid residues and has 96% identity with AT1A. No conspicuous difference in the ligand binding characteristics was observed between AT1A and AT1B. The mRNA for AT1B was expressed in many tissues as is the case with AT1A, and most abundantly expressed in the adrenal glands in the Sprague-Dawley rats. The existence of two subtypes in the rat type I angiotensin II receptor might explain the diverse actions of angiotensin II in various tissues. 相似文献
4.
Sequence-dependent hydrolysis of RNA using modified oligonucleotide splints and RNase H 总被引:2,自引:0,他引:2
To cleave RNA molecules using RNase H in a site-specific manner, a short deoxyoligonucleotide (3-5mer) joining with 2'-O-methyl oligonucleotide(s) was designed as a DNA splint to be used. Model experiments were carried out using ribooligonucleotide substrates (9 and 18 mer). It was found that the use of this type of splints (9 mer) causes a unique cleavage by RNase H. For example, when 3'm (GA)d(AGAA)m(GGU)5' was used as a hybridization strand, 32pUCUUUCUUCUUCCAGGAU was cleaved specifically between U11 and C12 to yield 32pUCUUUCUUCUU. This method will have a variety of applications for the study of RNA. 相似文献
5.
N Iwai M Matsunaga K Ogawa A Matsumori H Yoshida E Ohta C Kawai 《Biochemical and biophysical research communications》1987,143(1):288-293
Cos 7 cells transfected with human atrial natriuretic polypeptide (hANP) gene with SV40 enhancer and replication origin sequences expressed hANP gene. The expressed RNA was indistinguishable from native hANP mRNA and the transcribed protein seemed to be properly processed to alpha-hANP and beta-hANP. This system provides a useful approach to investigate the processing of hANPs and the structure-function relationship of amino acid sequences of hANPs. 相似文献
6.
A new solid-phase synthesis of oligoribonucleotides by the phosphoro-p-anisidate method using tetrahydrofuranyl protection of 2''-hydroxyl groups. 总被引:3,自引:3,他引:0 下载免费PDF全文
Six nonaribonucleotides containing the 5'-splice site, one complementary nonamer and an octadecamer containing the 3'-splice site have been synthesized on a polymer support using the phosphoro-p-anisidate method. A 5'-linked 2'-O-tetrahydrofuranyl-N-protected nucleoside 3'-(o-chlorophenyl)phosphoro-p-anisidate was used as the starting nucleotide, and the chain elongated in the 3'-direction by removing the p-anisidate protecting group with isoamyl nitrite under neutral conditions. The octadecamer has been synthesized using dinucleotide blocks and a 3'-terminal trinucleotide. 相似文献
7.
8.
Localization of cytochrome P-450 in the colonic mucosa of 3-methylcholanthrene-pretreated and untreated rats An immunohistochemical study 总被引:1,自引:0,他引:1
Dr. Shinji Tamura Sumio Kawata Mitsuhiro Okamoto Seiichiro Tarui 《Cell and tissue research》1988,252(2):397-401
Summary Immunohistochemical localization of cytochrome P-450 in the colonic mucosa of 3-methylcholanthrene-pretreated and untreated rats was studied by indirect fluorescent antibody staining technique. A polyclonal antibody for cytochrome P-450MC purified from hepatic microsomes of 3-methylcholanthrene-pretreated rats was used for this experiment. A strong immunofluorescence was found to be localized in the cytoplasm of the surface epithelium of the mucosa in the colon of 3-methylcholanthrene-pretreated rats. A faint immunofluorescence was also observed in the epithelium of untreated rats. 7-Ethoxycoumarin O-deethylase activity of colonic microsomes was significantly enhanced by 3-methylcholanthrene-pretreatment in parallel with an increase in the intensity of immunostaining for cytochrome P-450MC in Western blotting analysis. This is the first report on the localization of cytochrome P-450 in the colonic mucosa. 相似文献
9.
M Iwai M Kashiwadani T Takino Y Ibata 《Virchows Archiv. B, Cell pathology including molecular pathology》1988,55(2):117-123
Immunoreaction of alpha-fetoprotein (AFP) has been described in cholangiolar "oval" cells in the early stage of 3'-methyl-4-dimethylaminoazobenzene hepatocarcinogenesis. The subcellular location of AFP in the oval cells was in the perinuclear space, rough endoplasmic reticulum and Golgi apparatus. In livers with hyperplastic nodules there were two different types of foci containing AFP-positive cells. One type had a normal nucleocytoplasmic ratio and was seen in well-preserved hepatic trabecular structures, and the other had less cytoplasm and occurred in trabecular structures in disarray. AFP-immunoreactivity in the former type was visible in the perinuclear space and rough endoplasmic reticulum but scarce in the Golgi apparatus, and in the latter type it was present in the proliferative smooth endoplasmic reticulum and in several parts of Golgi apparatus in the submembranous or pericanalicular areas. In livers with hepatocarcinoma, AFP immunoreaction was detected in well-differentiated hepatocellular carcinomas, and the subcellular location of AFP was in the perinuclear space, rough endoplasmic reticulum and many developed Golgi complexes. Therefore, AFP-positive cells in livers with hyperplastic nodules are a new cell population in hepatocarcinogenesis, and each type is morphologically different from the oval cell. 相似文献
10.
T cell subsets responsible for clearance of Sendai virus from mouse lungs determined by adoptive transfer of immune spleen cell fractions to infected nude mice. T cells with antiviral activity developed in spleens by 7 days after intranasal infection. Spleen cell fractions depleted of Lyt-2+, Lyt-1+, or L3T4+ cells showed antiviral activity in vivo, although the degree of the activity was lower than that of control whole spleen cells. The antiviral activity of the Lyt-2+ cell-depleted fraction was consistently higher than that of L3T4+ (Lyt-1+)-depleted cells. In vitro cytotoxic activity against Sendai virus-associated, syngeneic lipopolysaccharide-blast cells was detected in stimulated cells from intraperitoneally immunized mice but was lost after depletion of Lyt-2+ cells. Multiple injection of anti-Sendai virus antibody into infected nude mice had no effect on lung virus titer. These results indicate that L3T4+ (Lyt-1+) and Lyt-2+ subsets are cooperatively responsible for efficient clearance of Sendai virus from the mouse lung. 相似文献