全文获取类型
收费全文 | 738篇 |
免费 | 158篇 |
国内免费 | 1篇 |
出版年
2021年 | 15篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 13篇 |
2016年 | 19篇 |
2015年 | 18篇 |
2014年 | 32篇 |
2013年 | 33篇 |
2012年 | 41篇 |
2011年 | 31篇 |
2010年 | 31篇 |
2009年 | 21篇 |
2008年 | 16篇 |
2007年 | 32篇 |
2006年 | 24篇 |
2005年 | 15篇 |
2004年 | 14篇 |
2003年 | 17篇 |
2002年 | 16篇 |
2001年 | 22篇 |
2000年 | 18篇 |
1999年 | 22篇 |
1998年 | 15篇 |
1997年 | 14篇 |
1995年 | 10篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 17篇 |
1991年 | 23篇 |
1990年 | 17篇 |
1989年 | 17篇 |
1988年 | 15篇 |
1987年 | 9篇 |
1986年 | 18篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1981年 | 13篇 |
1980年 | 10篇 |
1979年 | 12篇 |
1978年 | 12篇 |
1977年 | 17篇 |
1976年 | 15篇 |
1975年 | 11篇 |
1974年 | 9篇 |
1973年 | 16篇 |
1972年 | 11篇 |
1968年 | 13篇 |
1966年 | 11篇 |
排序方式: 共有897条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
Rayna Rapp 《Medical anthropology quarterly》2001,15(4):466-477
This article tracks the growth of medical anthropology in the United States in the decades since the 1970s, as it has intersected the expansion of feminist activism and scholarship. I argue that feminist attention to embodied inequalities quickly focused on reproduction as a site of investigation and intervention. Medical anthropology has benefited from feminist concern with stratified reproduction, especially its interrogation of nonnormative and stigmatized fertility and childbearing. When reproduction becomes problematic, it provides a lens through which cultural norms, struggles, and transformations can be viewed. Examples drawn from prenatal diagnosis are particularly revelatory of the diverse interests and stakes we all hold in reproduction. 相似文献
7.
Role of c-myc and other genes in interleukin 2 regulated CT6 T lymphocytes and their malignant variants 总被引:6,自引:0,他引:6
J L Cleveland U R Rapp W L Farrar 《Journal of immunology (Baltimore, Md. : 1950)》1987,138(10):3495-3504
The cloned murine cytotoxic T cell line CT6 solely requires interleukin 2 (IL 2) for viability and cell cycle progression. Treatment of G arrested cultures of CT6 cells with recombinant IL 2 induces the rapid sequential expression of the nuclear proto-oncogenes c-fos, c-myc, and c-myb but does not affect the expression of several cytosolic or membrane-associated proto-oncogenes. A comparison of early genes induced by growth factor treatment of quiescent NIH/3T3 fibroblasts and CT6 cells demonstrated that only c-fos and c-myc induction is shared in the two different lineages. Factor-independent lines derived from CT6 cells show no mitogenic response to IL 2, yet binding of IL 2 with its receptor in the cells was capable of inducing the expression of c-fos and c-myc. In factor-independent cell lines, c-myc was uniformly expressed at high constitutive levels, suggesting that c-myc abrogates growth factor requirements of these cells. The levels of c-myc expression in the factor-independent lines was not due to an autocrine production of IL 2 but may be a consequence of constitutively activated IL 2 receptors. 相似文献
8.
Complete sequence of the coding region of human elongation factor 2 (EF-2) by enzymatic amplification of cDNA from human ovarian granulosa cells 总被引:4,自引:0,他引:4
G Rapp J Klaudiny G Hagendorff M R Luck K H Scheit 《Biological chemistry Hoppe-Seyler》1989,370(10):1071-1075
The use of two primers allowed the specific enzymatic amplification of elongation factor 2 starting with total double-stranded cDNA from human ovarian granulosa cells. The amplified DNA fragment with a length of 1765 bp was restricted and sequenced by the shot gun approach. From the sequences obtained from the amplified fragment and the cDNA insert of pHGR81 [Rapp et al. (1988) Biol. Chem. Hoppe-Seyler 369, 247-250] respectively, the DNA sequence containing the complete coding as well as the 3'-untranslated region was assembled. 相似文献
9.
Effect of micelle diameter on tryptophan dynamics in an amphipathic helical peptide in phosphatidylcholine 总被引:1,自引:0,他引:1
The effect of dimyristoylphosphatidylcholine (DMPC) on the conformation and environment of the single tryptophan residue of a model amphipathic helical polypeptide has been investigated by fluorescence quenching with a water-soluble, neutral quencher (acrylamide) and multiple-frequency phase fluorometry. The peptide H-Ser-Ser-Ala-Asp-Trp-Leu-Lys-Ala-Phe-Tyr-Asp-Lys-Val-Ala-Glu-Lys-Leu-Ly s-Glu- Ala-Phe-Ser-Ser-Ser-OH [18As; Kanellis, P., Romans, A.Y., Johnson, B.J., Kercret, H., Chiovetti, R., Jr., Allen, T.M., & Segrest, S.P. (1980) J. Biol. Chem. 255, 11464] was synthesized by solid-phase techniques. Peptide was incubated at 26 degrees C with DMPC at various peptide:lipid weight ratios. The diameter of the resulting disk-shaped micelles increases with increasing lipid concentration from 12.0 +/- 0.4 nm at a 1:1 weight ratio of peptide to lipid to a maximum of 48.7 +/- 1.0 nm at a 1:13 ratio. At a weight ratio of 1:5, the average diameter is 22.7 +/- 0.6 nm. Decreasing the peptide:lipid ratio of the micelle resulted in a blue-shift in the fluorescence emission maximum (from 337 nm at 1:1 to 334 nm at 1:5), an increase in the fluorescence lifetime of the tryptophan measured by the phase shift method at 18 MHz (from 3.12 ns at 1:1 to 3.61 ns at 1:5), a decrease in the rate of fluorescence quenching by acrylamide (from 0.87 x 10(9) M-1 s-1 at 1:1 to 0.42 x 10(9) M-1 s-1 at 1:5), and an increase in the activation energy for quenching (from 6.7 kcal/mol at 1:1 to 12.7 kcal/mol at 1:5).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
10.
Many theoretical studies in biological and physical sciences consider the dynamical behavior of ann-dimensional ordinary differential equation that contains a large number of independent parameters. A frequently asked question is, are there permissible parameter sets that result in periodic or chaotic behavior? The large number of distinct parameters often limits the feasibility of trial and error calculations. The large dimension and nonlinearity of the system make application of analytic methods at best difficult and at worst effectively impossible. It is shown here that a computational search for parameter-dependent transitions of attractor topology can be effected by constrained optimization of quantitative measures of dynamical behavior (Hurwitz polynomials, Floquet coefficients, Lyapunov exponents and correlation dimension). As an example, we examine a three-dimensional nonlinear ordinary differential equation containing seven parameters that was constructed by Goldbeter and Segel to model periodic synthesis of cyclic AMP inDictyostelium. A search for bifurcations to periodic solutions is made by minimizing Hurwitz coefficients subject to parameter constraints. By comparing four optimization algorithms, the defects and advantages of the procedure are identified. It is also argued that it may be possible to use this characterization of dynamics to construct optimal responses to dynamical diseases (those disorders that result from parameter-dependent bifurcations in physiological control systems). 相似文献