全文获取类型
收费全文 | 641篇 |
免费 | 39篇 |
国内免费 | 76篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 23篇 |
妇产科学 | 9篇 |
基础医学 | 48篇 |
口腔科学 | 15篇 |
临床医学 | 95篇 |
内科学 | 191篇 |
皮肤病学 | 38篇 |
神经病学 | 29篇 |
特种医学 | 90篇 |
外科学 | 48篇 |
综合类 | 81篇 |
预防医学 | 7篇 |
药学 | 60篇 |
中国医学 | 1篇 |
肿瘤学 | 20篇 |
出版年
2021年 | 4篇 |
2019年 | 3篇 |
2018年 | 10篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 24篇 |
2012年 | 15篇 |
2011年 | 18篇 |
2010年 | 29篇 |
2009年 | 23篇 |
2008年 | 20篇 |
2007年 | 63篇 |
2006年 | 38篇 |
2005年 | 22篇 |
2004年 | 27篇 |
2003年 | 16篇 |
2002年 | 14篇 |
2001年 | 14篇 |
2000年 | 25篇 |
1999年 | 15篇 |
1998年 | 26篇 |
1997年 | 25篇 |
1996年 | 32篇 |
1995年 | 20篇 |
1994年 | 12篇 |
1993年 | 23篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 4篇 |
1989年 | 17篇 |
1988年 | 4篇 |
1987年 | 14篇 |
1986年 | 13篇 |
1985年 | 17篇 |
1984年 | 5篇 |
1983年 | 10篇 |
1982年 | 13篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1964年 | 3篇 |
1957年 | 3篇 |
排序方式: 共有756条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
柴胡皂甙q及其甙元的结构鉴定 总被引:4,自引:0,他引:4
从小叶黑柴胡(Bupleurum smithii Wolffvar;parvifolium ShanetY.Li)的根中得到3个化合物,柴胡皂甙元A和Q及柴胡皂甙q。柴胡皂甙元Q和柴胡皂甙q为新化合物,根据理化性质和波谱分析,确定其结构分别为齐墩果烷-11,13(18)-二烯-3β,16β,23,28,30-五醇和3β,16β,23,28,3O-五羟基齐墩果烷-11,13(18)-二烯-3-O-β-D-吡喃葡萄糖基(1→6)-[α-L-吡喃鼠李糖基(1→4)]-β-D-吡喃葡萄糖甙。 相似文献
95.
Ibuprofen-associated pure white-cell aplasia 总被引:1,自引:0,他引:1
S W Mamus J D Burton J D Groat D A Schulte M Lobell E D Zanjani 《The New England journal of medicine》1986,314(10):624-625
96.
Long-term repopulating ability of xenogeneic transplanted human fetal liver hematopoietic stem cells in sheep. 总被引:11,自引:2,他引:11 下载免费PDF全文
E D Zanjani A W Flake H Rice M Hedrick M Tavassoli 《The Journal of clinical investigation》1994,93(3):1051-1055
We previously reported on the successful engraftment and long-term multilineage expression (erythroid, myeloid, lymphoid) of human fetal liver hematopoietic stem cells in sheep after transplantation in utero. That the engraftment of long-term repopulating pluripotent stem cells occurred in these animals was shown here by the fact that transplantation of human CD45+ cells isolated from bone marrow of these chimeric animals into preimmune fetal sheep resulted in engraftment and expression of human cells. Marrow cells were obtained from three chimeric sheep at 3.2-3.6 yr after transplant. The relative percentage of human CD45+ cells present in these marrows was 3.3 +/- 0.32%. A total of 29 x 10(6) CD45+ cells were isolated by panning, pooled, and transplanted into six preimmune sheep fetuses (4.8 x 10(6) cells/fetus). All six recipients were born alive. Hematopoietic progenitors exhibiting human karyotype were detected in marrows of two lambs soon after birth. Cells expressing human CD45 antigen were also detected in blood and marrow of both lambs. Human cell expression has been multilineage and has persisted for > 1 yr. These results demonstrate that the expression of human cells in this large animal model resulted from engraftment of long-term repopulating pluripotent human stem cells. 相似文献
97.
Gestational age of recipient determines pattern and level of transgene expression following in utero retroviral gene transfer. 总被引:2,自引:0,他引:2
Christopher D Porada Paul J Park Gra?a Almeida-Porada Wansheng Liu Ferhat Ozturk Hudson A Glimp Esmail D Zanjani 《Molecular therapy》2005,11(2):284-293
The direct vector injection approach was used in the fetal sheep model of in utero gene therapy to determine the effects of the recipient gestational age on the efficacy and pattern of liver, lung, and brain transduction and transgene expression. The livers contained foci of transgene-expressing hepatocytes and demonstrated an inverse correlation between recipient age and hepatocyte transduction/transgene expression, with higher levels of gene transfer/expression early in gestation and lower levels late in gestation. Conversely, the percentage of transgene-expressing cells within the lungs of these same animals increased with gestational age, with the majority of transduction occurring in epithelium and fibroblasts. In contrast to the lung and liver, transgene-expressing cells within the brain were extremely limited at all gestational ages tested. Our results demonstrate that numerous nonhematopoietic cells within the liver and lung are transduced following direct injection of murine retroviral vectors into fetal sheep and suggest that the developmental stage of each organ at the time of injection may determine its susceptibility to in utero gene transfer and subsequent levels of transgene expression. Our results suggest that with further vector optimization this approach may be useful for treating diseases that involve the lung and liver early in development. 相似文献
98.
Braun HJ Wilcox-Fogel N Kim HJ Pouliot MA Harris AH Dragoo JL 《Knee surgery, sports traumatology, arthroscopy》2012,20(9):1689-1695
Purpose
Local anesthetic and corticosteroid combination injections are often used in clinical practice, however research investigating the chondrotoxic properties of these combinations is minimal. The goal of this study was to evaluate the effect of single injection doses of 1% lidocaine or 0.25% bupivacaine in combination with single injection doses of dexamethasone sodium phosphate (Decadron?), methylprednisolone acetate (Depo-Medrol?), betamethasone sodium phosphate and betamethasone acetate (Celestone? Soluspan?), or triamcinolone acetonide (Kenalog?) on human chondrocyte viability.Methods
All treatment conditions were delivered to human chondrocytes in vitro for the medication’s respective average duration of action using a bioreactor containing a continuous infusion pump constructed to mimic joint fluid metabolism. A two-color fluorescence assay was used to evaluate cell viability. A mixed-effects regression model was used to evaluate the mean differences in cell viability between treatment groups.Results
At 14?days, a single injection dose of 1% lidocaine or 0.25% bupivacaine in combination with betamethasone sodium phosphate and betamethasone acetate solution illustrated significant chondrotoxicity when compared with the local anesthetics alone (P?0.01). Methylprednisolone acetate and Triamcinolone acetonide both showed significant evidence of chondrotoxicity (P?=?0.013; P?=?0.016, respectively) when used in combination with 1% lidocaine compared with lidocaine alone, but showed no significant chondrotoxicity in combination with 0.25% bupivacaine (P’s?=?n.s.).Conclusions
Clinicians should use caution when injecting 1% lidocaine or 0.25% bupivacaine in conjunction with betamethasone sodium phosphate and betamethasone acetate solution due to its pronounced chondrotoxic effect in this study. 1% lidocaine used in combination with methylprednisolone acetate or triamcinolone acetonide also led to significant chondrotoxicity. 相似文献99.
Monoclonal antibody BA-1 binds to B lymphocytes, to cells from most cases of non-T acute lymphoblastic leukemia (ALL), and weakly to neutrophils. To determine whether BA-1 also reacts with hematopoietic progenitor cells (HPC), we studied the effect of removal of BA-1+ cells from human bone marrow on the proliferation in vitro of the trilineage precursor cell CFU-GEMM, and on the committed progenitor cells of granulopoiesis (CFU-C) and erythropoiesis (BFU-E/CFU-E). Complement- mediated cytotoxicity using BA-1 at concentrations far beyond those required to lyse BA-1+ bone marrow cells and ALL cells did not result in inhibition of colony formation in any of the assays. A rosette separation method, using ox red blood cells coated with BA-1, resulted in enrichment of HPC in the BA-1-depleted interface, whereas very few HPC were found in the BA-1-enriched pellet. Both methods indicate that BA-1 does not bind to HPC, although binding of the antibody to the lymphohematopoietic stem cell cannot be excluded yet. The high cytotoxic capacity of the IgM antibody BA-1, and the lack of reactivity with HPC, make the antibody particularly suitable for use in autologous bone marrow transplantation for patients with ALL. 相似文献
100.
Human platelets exert cytotoxic effects on tumor cells 总被引:6,自引:0,他引:6
Monocytes are thought to play a role in host resistance to tumor cell growth in animals and humans. In addition, platelets are known to be involved in tumor metastases. To investigate the interaction of these two cell types and their effect on tumor cells, human monocytes and platelets were examined using an in vitro monocyte-tumor cell cytotoxicity assay. Monocytes alone resulted in 32% +/- 1.5 (mean +/- SEM) tumor cell kill. When platelets were added to monocytes in a 1:1 ratio, an increase in cytotoxicity to 61% +/- 3.2 was observed. The cytotoxicity noted when platelets were added to a fixed number of monocytes and tumor cells was dependent on the number of platelets added. A decrease in cytotoxicity from 32% +/- 1.5 to 12% +/- 2.3 was observed when contaminating platelets were removed from monocyte preparations. Platelets added to tumor cells in the absence of any monocytes were also toxic, resulting in a maximum kill of 95% at a 4:1 platelet/tumor cell ratio. Secreted products of freshly isolated platelets may be responsible for much of the observed cytotoxicity, since supernatants from the platelets were toxic for tumor cells. Platelets pretreated with a cyclooxygenase inhibitor (ASA) or a lipoxygenase inhibitor had decreased cytotoxicity compared with untreated platelets. Our results indicate that products of platelet arachidonate metabolism are toxic for tumor cell lines. They also suggest that the role of the platelet must be considered when studying monocyte-tumor cell cytotoxicity. 相似文献