全文获取类型
收费全文 | 7022篇 |
免费 | 398篇 |
国内免费 | 2篇 |
专业分类
7422篇 |
出版年
2023年 | 13篇 |
2022年 | 46篇 |
2021年 | 75篇 |
2020年 | 53篇 |
2019年 | 68篇 |
2018年 | 106篇 |
2017年 | 94篇 |
2016年 | 144篇 |
2015年 | 227篇 |
2014年 | 245篇 |
2013年 | 449篇 |
2012年 | 452篇 |
2011年 | 471篇 |
2010年 | 289篇 |
2009年 | 278篇 |
2008年 | 423篇 |
2007年 | 442篇 |
2006年 | 418篇 |
2005年 | 386篇 |
2004年 | 380篇 |
2003年 | 395篇 |
2002年 | 330篇 |
2001年 | 121篇 |
2000年 | 123篇 |
1999年 | 115篇 |
1998年 | 85篇 |
1997年 | 85篇 |
1996年 | 64篇 |
1995年 | 90篇 |
1994年 | 63篇 |
1993年 | 60篇 |
1992年 | 65篇 |
1991年 | 65篇 |
1990年 | 69篇 |
1989年 | 54篇 |
1988年 | 44篇 |
1987年 | 41篇 |
1986年 | 43篇 |
1985年 | 47篇 |
1984年 | 42篇 |
1983年 | 42篇 |
1982年 | 32篇 |
1981年 | 46篇 |
1980年 | 23篇 |
1979年 | 24篇 |
1978年 | 21篇 |
1976年 | 24篇 |
1975年 | 19篇 |
1974年 | 16篇 |
1968年 | 15篇 |
排序方式: 共有7422条查询结果,搜索用时 0 毫秒
31.
Hiroshi Ashihara Atsushi Komamine Masami Shimokoriyama 《Journal of plant research》1974,87(2):121-131
Changes in activities of the glycolytic and pentose phosphate (PP) pathways in glucose catabolism in various parts of the
hypocotyls obtained from 4-day-old etiolatedPhaseolus mungo seedlings were investigated by measuring the inhibition rates of respiration by iodoacetate and malonate, and the release
of14CO2 from [1-14C]- and [6-14C]glucose. The relative activity of the PP pathway in glucose catabolism was higher in the immature part (Part I) and the
aged part (Part V) of the hypocotyls than in the intermediary one (Part III), while the activity of the glycolytic pathway
decreased with aging.
On a fresh weight basis, the enzyme activities of the glycolytic and PP pathways were higher in Part I than in Parts III and
V. On a protein content basis, however, activities of the enzymes of the PP pathway increased with aging and differentiation
of the hypocotyls whereas those of the glycolytic pathway decreased. Levels of nicotinamide adenine nucleotides were found
to be in the following order: Part I>Part III> Part V for NAD++NADH; Part I>Part V>Part III for NADP++NADPH. The stimulative effect of methylene blue on decreasing the C6/C1 ratio was greater in Part III than in Part I, and No effect was observed in Part V.
These data suggest that a decrease in the activity of the glycolytic pathway with aging and differentiation may be due to
the decreasing glycolytic enzyme activities and NAD(H) content. The higher activity of the PP pathway in the immature part
is attributable to larger amounts of NADP(H) and enzymes of the PP pathway. The greater contribution of the PP pathway to
glucose catabolism in the aged part than in the intermediary part seems to results from a more active turnover of NADP and
the relatively higher activity of the enzymes of the PP pathway than those of the glycolytic pathway. 相似文献
32.
It was ascertained that thymidine-3H added exogenously is incorporated periodically into the nucleus of the fertilized and the artificially activated eggs of Pseudocentrotus, Temnopleurus and Anthocidaris. Eggs stimulated insufficiently with butyric acid did not show any enhancement of incorporation of thymidine-3H. However, repetition of an insufficient stimulation induced incorporation of thymidine to some degree, although no visible cortical changes occurred. 相似文献
33.
34.
35.
36.
Yukimaru Sugiyama 《Primates; journal of primatology》1960,2(2):109-148
37.
38.
Establishment of five human myeloma cell lines 总被引:3,自引:0,他引:3
Masayoshi Namba Takemi Ohtsuki Masaharu Mori Atsushi Togawa Hideho Wada Takashi Sugihara Yoshihito Yawata Tetsuo Kimoto 《In vitro cellular & developmental biology. Plant》1989,25(8):723-729
Summary Five human myeloma cell lines, KMM-1, KMS-5, KMS-11, KMS-12- PE, and KMS-12-BM, have been established at Kawasaki Medical
School since 1980. As the KMS-12-PE and KMS-12-BM lines were obtained from the same patient, these five cell lines have been
derived from four patients with multiple myeloma. The five myeloma cell lines are stably growing at present in RPMI 1640 medium
supplemented with 10% fetal bovine serum. They can also grow in a defined culture medium without serum. That these cell lines
were, human myeloma cells was confirmed by the following findings. Ultranstructually, all five cell lines showed features
characteristic of plasma cells. KMM-1 and KMS-11 cells secreted lambda and kappa chains into the culture medium, respectively,
but the other cell lines produced no immunoglobulins. KMM-1 expressed cytoplasmic lambda antigen, KMS-5 showed cytoplasmic
delta, and KMS-11 expressed surface kappa, whereas KMS-12-PE and KMS-12-BM cells showed no surface or cytoplasmic immunoglobulins.
Regarding reaction with a monoclonal plasma cell antibody (PCA-1), four of the five lines were positive, the exception being
KMS-5. Another monoclonal antibody (CD38), which also recognizes plasma cells, reponded to KMM-1, KMS-12-PE, and KSM-12-BM.
KMS-5 cells expressed acute lymphoblastic leukemia antigens (CALLA). These data suggest that such lines as KMM-1, KMS-11,
KMS-12-PE, and KMS-12-BM represent later stages of B-cell differentiation, and that KMS-5 represents a relatively early stage
of B-cell differentiation. All the cell lines lacked Epstein-Barr virus nuclear antigen, showed abnormal karyotypes of human
origin, and differed from each other in the isozyme patterns examined. Only KMS-5 was tumorigenic when transplanted subcutaneously
into nude mice. 相似文献
39.
S. Kitazawa A. Takenaka N. Abe S. Maeda M. Horio T. Sugiyama 《Histochemistry and cell biology》1989,92(3):195-199
Summary An in vivo 5-bromodeoxyuridine (BrdUrd) labeled DNA probe was used for in situ DNA-RNA hybridization. BrdUrd was incorporated into plasmid DNA by inoculating E. coli with Luria-Bertani (LB) culture medium containing 500 mg/L of BrdUrd. After purification of the plasmid DNA, specific probes of the defined DNA fragments, which contained the cloned insert and short stretches of the vector DNA, were generated by restriction endonuclease. The enzymatic digestion pattern of the BrdUrd-labeled plasmid DNA was the same as that of the non-labeled one. BrdUrd was incorporated in 15%–20% of the total DNA, that is, about 80% of the thymidine was replaced by BrdUrd. Picogram amounts of the BrdUrd-labeled DNA probe itself and the target DNA were detectable on nitrocellulose filters in dot-blot spot and hybridization experiments using a peroxidase/diaminobenzidine combination. The BrdUrd-labeled DNA probe was efficiently hybridized with both single stranded DNA on nitrocellulose filters and cellular mRNA in in situ hybridization experiments. Through the reaction with BrdUrd in single stranded tails, hybridized probes were clearly detectable with fluorescent microscopy using a FITC-conjugated monoclonal anti-BrdUrd antibody. The in vivo labeling method did not require nick translation steps or in vitro DNA polymerase reactions. Sensitive, stable and efficient DNA probes were easily obtainable with this method. 相似文献
40.