全文获取类型
收费全文 | 1204篇 |
免费 | 119篇 |
国内免费 | 2篇 |
专业分类
1325篇 |
出版年
2023年 | 7篇 |
2022年 | 14篇 |
2021年 | 27篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 10篇 |
2017年 | 16篇 |
2016年 | 28篇 |
2015年 | 42篇 |
2014年 | 50篇 |
2013年 | 58篇 |
2012年 | 75篇 |
2011年 | 61篇 |
2010年 | 39篇 |
2009年 | 31篇 |
2008年 | 43篇 |
2007年 | 53篇 |
2006年 | 31篇 |
2005年 | 47篇 |
2004年 | 25篇 |
2003年 | 39篇 |
2002年 | 23篇 |
2001年 | 33篇 |
2000年 | 48篇 |
1999年 | 51篇 |
1998年 | 29篇 |
1997年 | 35篇 |
1996年 | 21篇 |
1995年 | 23篇 |
1994年 | 22篇 |
1993年 | 13篇 |
1992年 | 17篇 |
1991年 | 16篇 |
1990年 | 24篇 |
1989年 | 21篇 |
1988年 | 16篇 |
1987年 | 17篇 |
1986年 | 8篇 |
1984年 | 10篇 |
1983年 | 16篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 11篇 |
1976年 | 13篇 |
1975年 | 9篇 |
1974年 | 14篇 |
1973年 | 8篇 |
1972年 | 7篇 |
1971年 | 7篇 |
排序方式: 共有1325条查询结果,搜索用时 7 毫秒
1.
2.
An unusual case of neurofibrosarcoma of the cranio-orbital-maxillary region was resected by a combined neurosurgical and plastic surgical team. The resulting defect was reconstructed in one stage with a free rectus abdominis myocutaneous flap, obviating the need for subsequent prosthetic obturation of the maxillary defect. This reconstructive technique expedited the patient's convalescent period, allowing him to return to work 3 weeks following surgery. Wound healing was uneventful, and the cosmetic result was acceptable to the patient. 相似文献
3.
Summary Auxin-induced highly vacuolated thin-walled callus cells of several plant species, when ruptured, released large numbers of subcellular units most of which were enucleate. These enucleate microplasts are surrounded by an inner membrane of the cell, most probably derived from the tonoplast. When microplasts isolated fromSaintpaulia callus were cultured in a medium supplemented with growth substances they formed a thin wall and underwent budding. Microplasts could be useful for various studies in plant cell biology and for genetic manipulations. 相似文献
4.
Strategies for signal amplification in nucleic acid detection 总被引:3,自引:0,他引:3
S. Calin Andras J. Brian Power Edward C. Cocking Michael R. Davey 《Molecular biotechnology》2001,19(1):29-44
Many aspects of molecular genetics necessitate the detection of nucleic acid sequences. Current approaches involving target
amplification (in situ PCR, Primed in situ Labeling, Self-Sustained Sequence Replication, Strand Displacement Amplification), probe amplification (Ligase Chain Reaction,
Padlock Probes, Rolling Circle Amplification) and signal amplification (Tyramide Signal Amplification, Branched DNA Amplification)
are summarized in the present review, together with their advantages and limitations. 相似文献
5.
Cutting edge: precursor frequency affects the helper dependence of cytotoxic T cells. 总被引:3,自引:0,他引:3
Justine D Mintern Gayle M Davey Gabrielle T Belz Francis R Carbone William R Heath 《Journal of immunology (Baltimore, Md. : 1950)》2002,168(3):977-980
Generation of CTL immunity often depends on the availability of CD4 T cell help. In this report, we show that CTL responses induced by cross-priming can be converted from CD4-dependent to CD4-independent by increasing the frequency of CTL precursors. In the absence of CD4 T cells, high numbers of CTL precursors were able to expand in number and become effector CTL. The ability of high frequencies of CD8 T cells to override help was not due to their ability to signal CD40 via expression of CD154. These findings suggest that when precursor frequencies are high, priming of CD8 T cell responses may not require CD4 T cell help. 相似文献
6.
Summary The sensory receptor responsive to pressure applied internally to the ventral abdominal body wall of the blood-feeding insects, Rhodnius prolixus, is a single sense cell containing, at its distal end, a cilium enclosed within a scolopale, a densely staining structure characteristic of insect scolopidial sensilla. A small spherical structure lies within a dilation near the midregion of the cilium, and contains nine heavily staining bodies, the position of each corresponding to a pair of microtubules in the cilium. Proximal to the dilation, the microtubules are organized in a ring of nine pairs with one microtubule of each pair associated with dyneinlike arms. Dastal to the dilation a central pair of microtubules is present, but dyneinlike arms are absent. The scolopale cell, which gives risc to the scolopale, has cytoplasmic invaginations that form an elaborate array of extracellular compartments surrounding the body wall of the sense cell. These compartments may serve to dampen high frequency vibrations permitting the receptor to respond to pressure exerted by touch, an attribute in keeping with the receptor's proposed function of detecting abdominal distension related to the size and movement of the stomach. 相似文献
7.
8.
Gerard H. Markx Christopher L. Davey Douglas B. Kell Phillip Morris 《Journal of biotechnology》1991,20(3):279-290
A novel technique is described for the measurement of the volume fraction of biomass in a suspension by the simultaneous measurement of the conductivity of a suspension containing cells and of the medium in which the cells are suspended. The presence of non-conducting particulate matter in a suspension will cause the conductivity of a suspension to be decreased relative to that of the medium in which the particles are suspended. A simple equation (the Bruggeman equation) describes the relationship between the volume fraction of non-conducting particulate matter and the decrease in conductivity. The accuracy of this method for the determination of the biomass concentration of plant cells (Festuca arundinacea) in culture was shown. The method was successfully applied to the on-line determination of biomass concentrations during the growth of F. arundinacea cultures, and gave good agreement with biomass levels as determined from measurements of the radio-frequency dielectric permittivity of such cultures. 相似文献
9.
Larry R. Hilburn Ronald B. Davey John E. George J. Mathews Pound 《Experimental & applied acarology》1991,11(1):23-36
WhenBoophilus microplus and Type-II hybrids (B. microplus females×B. annulatus males) were released simultaneously onto bovine hosts, mating between the two forms appeared not to be at random. There were more contypic and fewer intertypic matings than predicted under an assumption of panmixia. An examination of the patterns of matings revealed that more of the matings on the first two days of detachment were between the two sexes ofB. microplus. Engorged females dropping on the last four days of maximum female detachment were predominantly hybrids mated to bothB. microplus and hybrid males. The non-random mating pattern does not appear to be caused by assortative mating betweenB. microplus and Type-II hybrids, but because theB. microplus were competnet to mate two days before the hybrids and theB. microplus males compete for mates of both types better than the Type-II males. 相似文献
10.
Approximately 106 protoplast-derived cell colonies of sainfoin were stressed with streptomycin and two resistant colonies were recovered. Plants regenerated from these colonies could be recallused on streptomycin-containing medium three years after growth in the absence of the antibiotic.Ultrastructural studies showed cells of resistant callus grown in the presence of streptomycin to contain chloroplasts with internal thykaloids and grana. Such mutant plants should be useful in designing biochemical selection schemes to recover somatic hybrids and cybrids.Abbreviations BAP
6 - benzylamino purine
- NAA
- napthaleneacetic acid 相似文献