全文获取类型
收费全文 | 4168篇 |
免费 | 378篇 |
国内免费 | 2篇 |
出版年
2023年 | 27篇 |
2022年 | 41篇 |
2021年 | 61篇 |
2020年 | 52篇 |
2019年 | 64篇 |
2018年 | 66篇 |
2017年 | 83篇 |
2016年 | 123篇 |
2015年 | 186篇 |
2014年 | 231篇 |
2013年 | 267篇 |
2012年 | 332篇 |
2011年 | 310篇 |
2010年 | 226篇 |
2009年 | 178篇 |
2008年 | 237篇 |
2007年 | 262篇 |
2006年 | 207篇 |
2005年 | 201篇 |
2004年 | 182篇 |
2003年 | 161篇 |
2002年 | 180篇 |
2001年 | 50篇 |
2000年 | 65篇 |
1999年 | 59篇 |
1998年 | 50篇 |
1997年 | 37篇 |
1996年 | 52篇 |
1995年 | 37篇 |
1994年 | 37篇 |
1993年 | 26篇 |
1992年 | 28篇 |
1991年 | 30篇 |
1990年 | 38篇 |
1989年 | 34篇 |
1988年 | 36篇 |
1987年 | 17篇 |
1986年 | 26篇 |
1985年 | 21篇 |
1984年 | 15篇 |
1983年 | 17篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 13篇 |
1977年 | 12篇 |
1976年 | 11篇 |
1975年 | 12篇 |
1973年 | 13篇 |
排序方式: 共有4548条查询结果,搜索用时 15 毫秒
1.
2.
3.
James A. Wanner 《American journal of physical anthropology》1977,47(1):99-102
An analysis of the anterior patellar groove of the human femur shows considerable variation in its medial and lateral spects. The groove itself, measured by the angle it encloses, shows considerably less variation than its individual components. The suggested functional relationship between bicondylar angle and lateral elevation of the patellar groove does not obtain for this sample. 相似文献
4.
5.
6.
Daniel Hohl Barbara Ruf Olano Pierre A. de Viragh Marcel Huber Carol J. Detrisac Urs W. Schnyder Dennis R. Roop 《Differentiation; research in biological diversity》1993,54(3):25-34
Abstract. In this study we analyzed the expression patterns of loricrin in various species and tissues using immunohistochemistry, immunoblotting and Northern blots. Loricrin is a glycine-, serine- and cysteine-rich protein expressed very late in epidermal differentiation in the granular layers of normal mouse and human epidermis. Later on in differentiation, loricrin becomes cross-linked as a major component into the cornified cell envelope by the formation of Nɛ -(γ-glutamyl)lysine isopeptide bonds. This process either occurs directly or by the intermediate accumulation in L-keratohyaline granules of mouse epidermis and human acrosyringia. Loricrin was identified in all mammalian species analyzed by virtue of its highly conserved carboxy-terminal sequences revealing an electric mobility of ∼60 kDa in rodents, rabbit and cow and of ∼35 kDa in lamb and human on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Loricrin is expressed in the granular layer of all mammalian orthokeratinizing epithelia tested including oral, esophageal and fore-stomach mucosa of rodents, tracheal squamous metaplasia of vitamin A deficient hamster and estrogen induced squamous vaginal epithelium of ovary ectomized rats. Loricrin is also expressed in a few parakeratinizing epithelia such as BBN [N-butyl-N-(4–hydroxybutyl)nitrosamine]-induced murine bladder carcinoma and a restricted subset of oral and single vaginal epithelial cells in higher mammals. Our results provide further evidence that the program of squamous differentiation in internal epithelia of the upper alimentary tract in rodents and higher mammals differ remarkably. In addition, we also have noted the distinct distribution patterns of human loricrin and involucrin, another major precursor protein of the cornified cell envelope. 相似文献
7.
8.
9.
Chris J. van Koppen Marcel W. Hermanussen Kiek N. Verrijp Jaap F. Rodrigues de Miranda Arie J. Beld Jan-Willem J. Lammers Cees A. M. van Ginneken 《Life sciences》1987,40(26):2561-2570
Specific binding of [125I]-(−)-cyanopindolol to human tracheal smooth muscle membranes was saturable, stereo-selective and of high affinity (Kd=5.3±0.9 pmol/l and RT=78±7fmol/g tissue). The β1-selective antagonists atenolol and LK 203-030 inhibited specific [125I]-(−)-cyanopindolol binding according to a one binding site model with low affinity in nearly all subjects, pointing to a homogeneous β2-adrenoceptor population. In one subject using LK 203-030 a small β-adrenoceptor subpopulation could be demonstrated. The beta-mimetics isoprenaline, fenoterol, salbutamol and terbutaline recognized high and low affinity agonist binding sites. Isoprenaline's pKH- and pKL- values for the high and low affinity sites were 8.0±0.2 and 5.9±0.3 respectively. In functional experiments isoprenaline relaxed tracheal smooth muscle strips having intrinsic tone with a pD2-value of 6.63±0.19. 相似文献
10.
Control of phoR-dependent bacterial alkaline phosphatase clonal variation by the phoM region. 总被引:14,自引:9,他引:5
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
B L Wanner 《Journal of bacteriology》1987,169(2):900-903
phoR mutants with the wild-type Escherichia coli K-12 Var+ phoM region showed clonal variation of bacterial alkaline phosphatase synthesis, whereas mutants with the pho-510 Var- allele did not. The pho-510 mutation is responsible for the phoR mutant constitutive phenotype and probably arose in E. coli K-12 58F+ after X-ray mutagenesis over 40 years ago. I propose that the phoM region controls a change in state of bacterial alkaline phosphatase synthesis, at least in phoR mutants. Four possible molecular mechanisms for how phoM may act are discussed. 相似文献