全文获取类型
收费全文 | 1407篇 |
免费 | 119篇 |
国内免费 | 51篇 |
专业分类
1577篇 |
出版年
2024年 | 4篇 |
2023年 | 36篇 |
2022年 | 47篇 |
2021年 | 67篇 |
2020年 | 71篇 |
2019年 | 59篇 |
2018年 | 74篇 |
2017年 | 32篇 |
2016年 | 31篇 |
2015年 | 53篇 |
2014年 | 125篇 |
2013年 | 99篇 |
2012年 | 84篇 |
2011年 | 68篇 |
2010年 | 59篇 |
2009年 | 70篇 |
2008年 | 73篇 |
2007年 | 69篇 |
2006年 | 57篇 |
2005年 | 45篇 |
2004年 | 39篇 |
2003年 | 44篇 |
2002年 | 42篇 |
2001年 | 22篇 |
2000年 | 25篇 |
1999年 | 17篇 |
1998年 | 16篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 17篇 |
1992年 | 11篇 |
1991年 | 9篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1982年 | 3篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有1577条查询结果,搜索用时 15 毫秒
81.
Anderson LE Morris JE Miller DL Rafferty CN Ebi KL Sasser LB 《Bioelectromagnetics》2001,22(3):185-193
An animal model for large granular lymphocytic (LGL) leukemia in male Fischer 344 rats was utilized to determine whether magnetic field exposure can be shown to influence the progression of leukemia. We previously reported that exposure to continuous 60 Hz, 1 mT magnetic fields did not significantly alter the clinical progression of LGL leukemia in young male rats following injection of spleen cells from donor leukemic rats. Results presented here extend those studies with the following objectives: (a) to replicate the previous study of continuous 60 Hz magnetic field exposures, but using fewer LGL cells in the inoculum, and (b) to determine if intermittent 60 Hz magnetic fields can alter the clinical progression of leukemia. Rats were randomly assigned to four treatment groups (18/group) as follows: (1) 1 mT (10 G) continuous field, (2) 1 mT intermittent field (off/on at 3 min intervals), (3) ambient controls ( < 0.1 microT), and (4) positive control (5 Gy whole body irradiation from cobalt-60 four days prior to initiation of exposure). All rats were injected intraperitoneally with 2.2 x 10(6) fresh, viable LGL leukemic spleen cells at the beginning of the study. The fields were activated for 20 h per day, 7 days per week, and all exposure conditions were superimposed over the natural ambient magnetic field. The rats were weighed and palpated for splenomegaly weekly. Splenomegaly developed 9-11 weeks after transplantation of the leukemia cells. Hematological evaluations were performed at 6, 8, 10, 12, 14, and 16 weeks of exposure. Peripheral blood hemoglobin concentration, red blood cells, and packed cell volume declined, and total white blood cells and LGL cells increased dramatically in all treatment groups after onset of leukemia. Although the positive control group showed different body weight curves and developed signs of leukemia earlier than other groups, differences were not detected between exposure groups and ambient controls. Furthermore, there were no overall effects of magnetic fields on splenomegaly or survival in exposed animals. In addition, no significant and/or consistent differences were detected in hematological parameters between the magnetic field exposed and the ambient control groups. 相似文献
82.
Ben-Bassat H Chaouat M Zumai E Segal N Cinamon U Ron M Wexler MR Eldad A 《Cell and tissue banking》2000,1(4):303-312
The Israel National Skin Bank (INSB) was founded jointly by the Israel Defense Forces (IDF) Medical Corps and the Ministry of Health in 1986. The prime purpose of the Skin Bank is to treat burn victims incurred at war or during mass casualty incidences. The INSB Protocol is comprised of international skin bank protocols and our previous and present research results. They provide the framework for selecting optimal guidelines for procurement, processing, preservation, storage and evaluation of transplantation performance of viable skin grafts. For evaluation and direct comparison of graft performance of glycerolized or cryopreserved skin stored for long periods, we have applied a mouse recipient model developed by us. This model assesses graft performance before the rejection process takes place. The in vivo design has inherent clinical relevance, which is especially appealing. Cryopreserved skin performed better than glycerolized skin (p > 0.027), but fresh skin performed significantly better than cryopreserved skin (p > 0.003), as analyzed by the Mann–Whitney non-parametric test. Then graft performance of skin specimens were cryopreserved by programmed or stepwise freezing and stored at -80°C or in liquid nitrogen for 1 and 6–10 months was evaluated. The average score of skin preserved by programmed freezing and stored in liquid nitrogen is the highest for both storage periods. This method has a highly significant advantage (p < 0.007) over the others for 6–10 months storage, evaluated by graft adherence. Several interaction factors determine the quality of cryopreserved skin. Highly significant is the interaction factor/'combined effect' of sample variability with the method of cryopreservation or with the storage period. Finally, the results of paired comparison of selected histology criteria of cryopreserved to fresh skin indicated that storage of skin for up to 5 years did not impair significantly its performance compared to fresh skin, whereas, after six years of storage, there was a highly significant (p < 0.001) impairment in skin quality. We offer a simplified in vivo model and analysis for cryopreserved skin graft performance, suggesting that the evaluation procedures, which are issues of great interest in skin banking, may help future skin banks to make informed choices and decisions regarding quality issues. 相似文献
83.
Hematopoietic growth factors in autologous transplantation 总被引:1,自引:0,他引:1
Hematopoietic growth factors (HGFs) sustain the survival, proliferation and differentiation of hematopoietic stem cells and
some functions of mature blood cells. In man several HGFs have been characterised and cloned so far, and this has allowed
investigators to confer the rationale for the clinical application of these molecules in hematology and oncology. In particular
G-CSF and GM-CSF are currently utilised to abrogate the hematological toxicity of chemotherapy for standard and dose-intensified
therapy, neutropenia following bone marrow and peripheral blood stem cell transplantation. Moreover there has recently been
great interest in the ex vivo expansion of hematopoietic stem and progenitor cells for a variety of applications, such as
in vitro tumor cell purging or for reducing the volume of blood processed by the leukapheresis. Several combinations of HGFs
have been described to sustain the ex vivo survival and proliferation of these cells disclosing new opportunities in the field
of stem cells transplants. 相似文献
84.
Puthur Jos T. Prasad K.V.S.K. Sharmila P. Pardha Saradhi P. 《Plant Cell, Tissue and Organ Culture》1998,53(1):41-47
Investigations were carried out to achieve cent per cent transplantation success of micropropagated Leucaena leucocephala
(a fast growing multipurpose leguminous tree species) plantlets using two vesicular arbuscular mycorrhizal fungi, Glomus fasciculatum
and Glomus macrocarpum. Plantlets were obtained by rooting the shoots [obtained through; hypocotyl callus in presence of 10-5M BAP + 10-6M NAA; and axillary bud sprouting from cotyledonary and other nodes in presence of 10-5M BAP, on Gamborg's B5 medium], on half strength B5 medium supplemented with 5×10-6M IBA. Subsequent to the nodulation of their roots with Rhizobium (strain PRGL 001)in soilrite, these plantlets were tranferred
to sterilized garden soil by laying inoculum of either Glomus fasciculatum or Glomus macrocarpum around their roots. Only
20% of the plantlets survived in soils lacking VAM fungus. In contrast, cent per cent of the plantlets of Leucaena leucocephala
established very well and showed good growth in VAM inoculated soil. Roots of the later plantlets showed presence of both
external and internal hyphae with well formed arbuscules and vesicles confirming the establishment of good mycorrhizal association.
These studies convincingly demonstrate that the mycorrhizal association help in successful establishment of tissue culture
raised plantlets of Leucaena leucocephala in the field conditions by alleviating the transplantation shock.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
85.
A method for micropropagation ofDalbergia sissoo has been developed. Single node segments obtained from coppice shoots of a mature tree (20 – 25 year old) produced 3–4 shoots
per explant on Murashige and Skoog (MS) medium containing 4.4 x 10−6 M benzylaminopurine (BAP) and 4.4 × 10−7 M of Β-naphthoxy acetic acid (NOA) (shoot multiplication medium) within 4 weeks. Thein vitro regenerated shoots were 3 – 4 cm in length and provided 2 to 3 culturable nodal segments which on shoot multiplication medium
again produced 3–4 shoots. Following this procedure 18–24 shoots were produced from single nodal segment within 60 d. 80 %
of the shoots directly produced five roots when they were firstly treated with MS medium supplemented with 10−5 M indole-3-butyric acid (IBA) and subsequently transferred to half strength liquid MS medium containing 1 % activated charcoal
followed by half strength liquid MS free hormones, vitamins and activated charcoal. Thein vitro raised plants were hardened for survival after transplantation to soil by exposing them to various humidity conditions, gradually
from higher to low, with nearly 100 % transplant success.
Acknowledgement: Authors are grateful to CSIR and DST, New Delhi for financial assistance. 相似文献
86.
目的:探讨超微血流成像术用于肾移植患者术后评估的临床价值。方法:选取我院2019年2月-2019年8月收治的60例肾移植患者的临床资料,根据术后恢复情况分为A、B、C三组,A组(27例,术后肾功能恢复良好)、B组(20例,术后发生过敏肾功能异常病变但治疗后肾功恢复正常)、C组(13例,术后血肌酐水平持续增高肾功能异常者),三组均采用超微血管流成像术检测血管指数,比较不同组患者的血管指数并分析其与血肌酐水平的关系。结果:三组患者的肾移植长径、前后径、左右径、皮质厚度、叶间动脉阻力指数比较无显著差异(P0.05)。C组患者的肾皮质血管指数(23.34±6.03%)明显低于A组(33.23±3.45%)、B组(31.23±4.23%)(P0.05)。肾功能异常患者肾皮质的血管指数较低,且随着血肌酐水平的升高而下降,两者呈显著负相关(r=-0.23,P0.05)。结论:超声微血流成像术用于肾移植患者术后评估可较好地反映肾皮质血供及术后肾功能的变化。 相似文献
87.
88.
Mouse Offspring Derived from Fetal Ovaries or Reaggregates Which were Cultured and Transplanted into Adult Females 总被引:2,自引:3,他引:2
Koichiro Hashimoto Motoko Noguchi Norio Nakatsuji 《Development, growth & differentiation》1992,34(2):233-238
Primordial germ cells (PGCs) and gonia could be promising novel targets and vehicles for manipulation of the mammalian germ line. To make such manipulation a practical possibility, PGCs or gonia must be allowed to produce gametes and offspring after they were isolated from embryos and manipulated in culture. As the first step to develop such research strategy, we obtained offspring from mouse oogonia which were isolated from embryonic ovaries and cultured as dispersed cells before transplantation into female mice as reaggregates. 相似文献
89.
90.
目的:评价颈动脉内膜剥脱术(CEA)麻醉疗效,以及经颅多普勒超声(TCD)、微血管多普勒超声(MVD)应用的价值,以及适合颈动脉内膜剥脱术的适合麻醉方法。方法:回顾性分析苏州大学附属一医院脑卒中中心2012年5月至2013年5月所进行的颈动脉内膜剥脱术治疗的19名颅外颈动脉狭窄患者的资料。患者临床症状均伴有不同程度的脑缺血症状。颈动脉狭窄程度2例中度狭窄,17例重度狭窄。所有手术操作均全麻下在显微镜下操作。1例采用补片成形。18例术中采用TCD及MVD监测下完成,1例未采用超声监测。结果:手术成功率为100%,无死亡率。术前脑缺血症状术后患者均有恢复。未发现过度灌注的并发症。麻醉效果达到预期目的。结论:颈动脉内膜剥脱术在多普勒超声MVD及TCD监测下治疗颅外颈动脉狭窄是一种安全、有效的措施;全身麻醉下行CEA手术安全可靠。 相似文献