全文获取类型
收费全文 | 3152篇 |
免费 | 270篇 |
出版年
2023年 | 10篇 |
2022年 | 29篇 |
2021年 | 54篇 |
2020年 | 27篇 |
2019年 | 47篇 |
2018年 | 66篇 |
2017年 | 54篇 |
2016年 | 99篇 |
2015年 | 161篇 |
2014年 | 177篇 |
2013年 | 196篇 |
2012年 | 265篇 |
2011年 | 254篇 |
2010年 | 149篇 |
2009年 | 135篇 |
2008年 | 195篇 |
2007年 | 190篇 |
2006年 | 187篇 |
2005年 | 161篇 |
2004年 | 180篇 |
2003年 | 128篇 |
2002年 | 146篇 |
2001年 | 30篇 |
2000年 | 13篇 |
1999年 | 31篇 |
1998年 | 46篇 |
1997年 | 33篇 |
1996年 | 28篇 |
1995年 | 27篇 |
1994年 | 16篇 |
1993年 | 17篇 |
1992年 | 19篇 |
1991年 | 22篇 |
1990年 | 19篇 |
1989年 | 10篇 |
1988年 | 16篇 |
1987年 | 16篇 |
1986年 | 9篇 |
1985年 | 21篇 |
1984年 | 11篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 18篇 |
1980年 | 15篇 |
1979年 | 22篇 |
1978年 | 13篇 |
1976年 | 6篇 |
1974年 | 6篇 |
1973年 | 8篇 |
1967年 | 4篇 |
排序方式: 共有3422条查询结果,搜索用时 15 毫秒
21.
Amira Klip Denise Walker Kathleen J. Ransome Dean W. Schroer Gustav E. Lienhard 《Archives of biochemistry and biophysics》1983,226(1):198-205
The glucose transporter in the plasma membrane of rat skeletal muscle has been identified by two approaches. In one, the transporter was detected as the polypeptide that was differentially labeled by photolysis with [3H]cytochalasin B in the presence of l- and d-glucose. [3H]Cytochalasin B is a high-affinity ligand for the transporter that is displaced by d-glucose. In the other, the transporter was detected by means of its reaction with rabbit antibodies against the purified glucose transporter from human erythrocytes. By both procedures, the transporter was found to be a polypeptide with a mobility corresponding to a molecular weight of 45,000–50,000 upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 相似文献
22.
Maintenance and reversibility of active albumin secretion by adult rat hepatocytes co-cultured with another liver epithelial cell type 总被引:19,自引:0,他引:19
C Guguen-Guillouzo B Clément G Baffet C Beaumont E Morel-Chany D Glaise A Guillouzo 《Experimental cell research》1983,143(1):47-54
When adult rat hepatocytes were co-cultured with another liver epithelial cell type in a medium supplemented or not with fetal calf serum (FCS), it was found that 1. They survived for more than 2 months 2. Albumin secretion levels remained high over the whole culture period 3. Decreased secretion might be reversed 4. This protein secretion activity appeared to be dependent upon both the presence of cell-cell contacts and the production of an extracellular material. The results demonstrate for the first time long-term stabilization and reversibility of a specific function (albumin secretion) at high levels by adult hepatocytes cultured in serum-free medium and suggest that both the presence of other liver cell type(s) and the production of an extracellular matrix are needed for the maintenance of specific functions in cultured hepatocytes. 相似文献
23.
24.
Adelina A. Davies Stephen E. Moss Mark R. Crompton Tania A. Jones Nigel K. Spurr Denise Sheer Christine Kozak Michael J. Crumpton 《Human genetics》1989,82(3):234-238
Summary The gene encoding a tissue inhibitor of metalloproteinases, TIMP, has previously been shown to be X-linked in both the human and mouse genomes. We have used a series of somatic cell hybrids segregating translocation and deletion X chromosomes to map the TIMP gene on the human X chromosome. In combination with previous data, the gene can be assigned to Xp11.23Xp11.4. Genetic linkage analyses demonstrate that TIMP is linked to the more distal ornithine transcarbamylase (OTC) locus at a distance of about 22 centimorgans. The data are consistent with the conclusion that TIMP maps to a conserved synteny and linkage group on the proximal short arm of the human X chromosome and on the pericentric region of the mouse X chromosome, including loci for synapsin-1, a member of the raf oncogene family, OTC, and TIMP. 相似文献
25.
26.
Lateral asymmetry refers to unequal fluorescent intensity between adjacent regions of sister chromatids. It has been observed in the centromeric regions of mitotic chromosomes of mouse or human origin when cells are grown in 5-bromo-2-deoxyuridine (BrdU) for a single round of DNA synthesis. The chromosome-orientation fluorescence in situ hybridization (CO-FISH) technique was used with pseudodiploid mouse cells to show that the regions of asymmetrical brightness coincide with major satellite repetitive DNA, and that the more heavily BrdU-substituted chromatid is the one that fluoresces less brightly. These observations support a 20 year old hypothesis on the origin of lateral asymmetry. Other observations suggest that differential loss of DNA from the heavily substituted chromatid also contributes to lateral asymmetry. 相似文献
27.
Marcello Franco Eduardo Bagagli Marino Cunha Luiz Gastão Chamma Denise Fecchio 《Mycopathologia》1996,135(1):13-19
We investigated the occurrence of antigenic and biochemical variability among Paracoccidioides brasiliensis antigen batches prepared according to the same protocol. Initially (experiment #1), we analyzed two antigen lots of two human isolates (Bt1 & Bt2), cultured in two media (PYG: bactopeptone, yeast extract, glucose; MMM: McVeigh & Morton medium) in SDS-PAGE and in two immunological tests (imunodiffusion-ID and footpad swelling test-FPT). Afterwards (experiment #2), we compared the antigenic profile of three antigen batches from three human isolates (Bt1, Bt2 & Bt3) by two-dimensional immunoelectrophoresis (2 D-IEP) against a reference system for P. brasiliensis antigens. In experiment #1, there were important intra- and inter-strain antigenic differences between batches of the fungal isolates cultured on both media. The block titration of the antigen batches for the immunological tests revealed correlation between protein concentration and biological activity in ID and no correlation in FPT. In experiment #2, the reference system for P. brasiliensis showed 26 antigen peaks. There were important differences between batches prepared from the same isolate and between batches from different isolates. Our data suggested the occurrence of instability in the synthesis of antigenic components by a same P. brasiliensis isolate, under controlled incubation conditions. 相似文献
28.
29.
30.
Alec Breen Alan F. Rope Denise Taylor John C. Loper P. R. Sferra 《Journal of industrial microbiology & biotechnology》1995,14(1):10-16
Summary The use of DNA amplification fingerprinting (DAF) as a tool for monitoring mixed microbial populations in bioreactors was evaluated. Short (8-mer or 10-mer) oligonucleotides were used to prime DNA extracts from various biological reactors during polymerase chain reaction (PCR) amplification. The reactors examined in this study included two sets of anaerobic stirred tank continuous flow bioreactors. One set of anaerobic reactors was operated under methanogenic conditions and one set was operated under sulfate-reducing conditions. The anaerobic reactor communities in the methanol-fed reactors showed extensive DAF homology. DAF was also applied to a fixed-film azo dye degrading reactor to examine the degree of uniformity of colonization of the substratum in representative regions of the reactor. This method is a quick and relatively inexpensive means of monitoring microbial community structure during biological processes. Since no cultivation of the sample is involved, the genetic profile of the community is not biased by outgrowth conditions. DAF profiles may be useful for comparisons of population changes over time or of bench-scale vs pilot-scale reactors but not adequate for assessing community diversity. 相似文献