全文获取类型
收费全文 | 187513篇 |
免费 | 16981篇 |
国内免费 | 8468篇 |
专业分类
耳鼻咽喉 | 2363篇 |
儿科学 | 4272篇 |
妇产科学 | 2077篇 |
基础医学 | 34166篇 |
口腔科学 | 5601篇 |
临床医学 | 13904篇 |
内科学 | 26124篇 |
皮肤病学 | 4835篇 |
神经病学 | 10698篇 |
特种医学 | 4202篇 |
外国民族医学 | 118篇 |
外科学 | 16893篇 |
综合类 | 27716篇 |
现状与发展 | 49篇 |
预防医学 | 5730篇 |
眼科学 | 3693篇 |
药学 | 15742篇 |
30篇 | |
中国医学 | 5744篇 |
肿瘤学 | 29005篇 |
出版年
2024年 | 407篇 |
2023年 | 2979篇 |
2022年 | 5576篇 |
2021年 | 7091篇 |
2020年 | 6227篇 |
2019年 | 6242篇 |
2018年 | 6379篇 |
2017年 | 6511篇 |
2016年 | 6608篇 |
2015年 | 7605篇 |
2014年 | 11010篇 |
2013年 | 12066篇 |
2012年 | 10349篇 |
2011年 | 11704篇 |
2010年 | 9692篇 |
2009年 | 9319篇 |
2008年 | 9713篇 |
2007年 | 9848篇 |
2006年 | 8923篇 |
2005年 | 8315篇 |
2004年 | 7379篇 |
2003年 | 6350篇 |
2002年 | 5123篇 |
2001年 | 4418篇 |
2000年 | 3653篇 |
1999年 | 3295篇 |
1998年 | 3109篇 |
1997年 | 2851篇 |
1996年 | 2547篇 |
1995年 | 2264篇 |
1994年 | 1970篇 |
1993年 | 1637篇 |
1992年 | 1313篇 |
1991年 | 1250篇 |
1990年 | 961篇 |
1989年 | 906篇 |
1988年 | 843篇 |
1987年 | 682篇 |
1986年 | 648篇 |
1985年 | 912篇 |
1984年 | 880篇 |
1983年 | 581篇 |
1982年 | 630篇 |
1981年 | 536篇 |
1980年 | 433篇 |
1979年 | 343篇 |
1978年 | 247篇 |
1977年 | 190篇 |
1976年 | 153篇 |
1975年 | 79篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Hiroko Ida-Yonemochi Wael Swelam Chikara Saito Takashi Saku 《Journal of oral pathology & medicine》2005,34(1):59-61
A case of angiolipoma occurring in the buccal mucosa of a 69-year-old male is described. The patient had noticed a painless mass in his buccal mucosa for 2 years. The surgically removed tumor, measuring 9 mm in diameter, was mainly located in the submucosal layer with focal expansion into the muscle layer. Histologically, the tumor was well-demarcated and composed of proliferations of mature fat cells and fibrous connective tissue containing many small blood vessels, which were evenly distributed. There was diffuse infiltration of a large number of mast cells, which were immunopositive for vascular endothelial growth factor (VEGF) especially around blood vessels, suggesting that VEGF produced by mast cells in angiolipomas plays an important role in the vascular proliferation in this particular tumor. 相似文献
52.
A. Beamonte F. Goldfain-Blanc N. Casadevall D. Bazot H. Bertheux N. Claude 《Comparative clinical pathology》2005,14(1):61-65
As part of the early preclinical development of a new antipsychotic compound, Wistar rats of both sexes were dosed orally for upto 7 days. At high doses, expected changes in appearance and behavior, decreases in bodyweight gain and feed intake but also a fluid and pale bone marrow (BM) were observed. Blood cell counts were normal as were clinical chemical values. BM sections showed a red cell hypoplasia. Circulating reticulocytes and erythroblasts on BM smears were decreased suggesting that the compound might have a selective toxicity for the erythroid lineage. In a mechanistic experiment, rats were dosed for 9 days and phlebotomized after 7 days of exposure to stimulate erythroid regeneration. Red-blood cell mass, reticulocytes and erythropoietin (EPO) levels were monitored before and upto 48 h after bleeding. Results showed that an EPO-mediated pathogenesis could be excluded. The effect of the drug on the formation of Colony-forming units (CFU)-E and CFU-GM was then quantitatively measured in vitro after direct exposure to the compound. In two successive assays, rat or human BM cells were incubated with the drug dissolved in the collection medium at final concentrations of 0.3×10–7 –3×10–5 M. In the presence of adequate growth factors, CFU-E and CFU-GM were cultured and cell proliferation was compared between treated and control groups. Our results showed an expected inhibition by the drug of the growth of erythroid progenitors associated to a similar effect on myeloid progenitors. The CFU-E and CFU-GM of both human and rat sources were totally inhibited from the concentration of 3×10–5 M. The IC50 values were consistent with rat peak plasma levels reached in vivo by the drug. Therefore, the short-term cloning assays performed on rat BM cells were sensitive indicators of the hematotoxicity of the compound and were considered as predictive for human toxicity. 相似文献
53.
In primary visual cortex of hooded rats, pyramidal cells in layer V may be classified as long, medium, or short, on the basis of the layer in which the apical dendrite terminates. The present study determines which of these types of pyramidal cells project to the superior colliculus. Two different strategies were used to label corticotectal cells with horseradish peroxidase (HRP). In the first set of experiments, a large number of corticotectal cells were labeled by retrograde transport following injection of HRP into the superior colliculus. In the second set of experiments, single unit recording was used to identify corticotectal cells physiologically by antidromic activation from the superior colliculus. These cells were then impaled and labeled by intracellular iontophoresis of HRP. The results from both techniques suggest that only long pyramidal cells send an axon to the superior colliculus. These cells are distinguished by an apical dendrite that extends into layer I. We conclude that in hooded rats corticotectal cells in primary visual cortex are the long pyramids in layer V. 相似文献
54.
Summary This study was undertaken to elucidate, using the Golgi method, the neuropathological change in the brain of the macular mutant mouse, whose hemizygote (Ml/y) is considered to be a model of Menkes kinky hair disease (MKHD). The hemizygote mice gradually lost weight after 10 days of age and died with emaciation and seizure around day 15. The normal littermate (+/y) was well developed. In the cerebrum, the arborization of pyramidal neurons in the layer V of the Ml/y was the same as that in the +/y on day 10. However, development of arborization in the Ml/y was delayed in comparison with that in the +/y on days 12 and 14. Purkinje cells with several somal sprouts were observed in the cerebellum in both the Ml/y and +/y on day 7. The somal sprouts in the +/y had regressed gradually by day 12, while they were still in the anterior and middle lobes of the Ml/y on day 14. Additionally, the trunks of Ml/y stem dendrites became thicker and a cactus formation was recognized on the branching portion of the dendrites on day 14. Arborization of these abnormal Purkinje cells was distinctly poor compared with that in the +/y. These results suggest that the growth of the neurons is delayed in the Ml/y and simultaneously their cytoskeletal developments are disturbed, especially in the Purkinje cells. There is a close similarity in many respects to the neuropathological change in MKHD. 相似文献
55.
56.
57.
Objective To predict the HLA class Ⅰ restricted cytotoxic T lymphocyte epitopes for human proliferating cell nuclear antigen (PCNA). Methods By using 3 epitope prediction databases which including MHC binder ( BIMAS and SYFPEITHI databases) and proteasome cutting site ( PAProC databases), the epitopes of PCNA were predicted by analyzing several parameters and methods. Results After comprehensive analysis,we have obtained two possible HLA-A0201 restricted CTL epitopes SMSAD-VPLV (228-236, score 447 633. 595 ) and LINEACWDI ( 22-28, score 127 966.779);two HLA-A24 re-stricted CTL epitopos DYEMKLMDL ( 113-121, score 563 994.9 ) and EFARICRDL ( 143-151, score 40 540.7);two HLA-A1101 restricted CTL epitopes LTSMSKILK (72-80, score 1334. 2680 ) and DVPLV-VEYK (232-240,score 736.9236). Conclusion The multi-parameter epitope prediction method is feasi-ble for cytotoxic T lymphocyte epitope prediction. 相似文献
58.
目的 初步建立阴道粘膜上皮细胞体外培养方法,为阴道粘膜上皮研究提供实验模型.方法 取雌性新西兰大白兔阴道粘膜组织小块,胶原酶Ⅳ和胰蛋白酶联合消化分离法收集上皮细胞,接种于角朊细胞无血清培养液中静置培养、传代.动态观察细胞生长增殖情况,扫描和透射电镜观察超微结构,流式细胞仪测定细胞增殖周期,并进行免疫组织化学鉴定.结果 体外培养的阴道粘膜上皮细胞为二倍体细胞,增殖状态良好,细胞间可见桥粒连接,免疫组化角蛋白染色阳性.细胞的超微结构和免疫组化染色均具有上皮细胞特征.结论 在本实验条件下,体外培养的阴道粘膜上皮细胞具有较好的增殖能力,可作为阴道粘膜上皮研究的理想实验模型. 相似文献
59.
G. Burastero N. Sessarego G. Grappiolo C. Castellazzo S. Castello A. Pitto G. Cittadini M. Podesta G. Bovio M. Peresi E. Fulcheri F. Frassoni L. Spotorno 《Journal of orthopaedics and traumatology》2007,8(1):49-54
Mesenchymal stem cells (MSC), easily culture-expanded from bone marrow, can significantly enhance bone defect healing. Several
proteins, such as the bone morphogenetic proteins (BMPs) and in particular BMP-7, are involved in bone formation in vitro
and in vivo. In this preclinical study, we evaluated if the association of human MSC (hMSC) with BMP-7 had synergic action
on bone healing. Rat femoral defects (n=12) were treated with: autoclaved bone and mononucleated cells (MNC) as control group
G1; bone and hMSC, group G2; bone with BMP-7, group G3; bone and hMSC plus BMP-7, group G4. Defect regeneration was evaluated
with plain radiographs after 2, 4, 8 and 12 weeks and with histological analysis. We observed organized trabeculae bridging
between the osteotomic ends of the host bone in rats treated with the association of hMSC and rhBMP-7. These trabeculae, formed
by a core of devitalized tissue surrounded by osteoblasts, osteocytes and osteoclasts, were continuous with a cortical-like
structure of bony tissue. Such new bone formation of the group treated with the association of hMSC and rhBMP-7 (G4) was clearly
superior compared to rats treated with rhBMP-7 (G2) or hMSC (G3) alone, as shown by radiographic analysis and histological
study. The present study suggests that the association of hMSC and BMP-7 is more effective than hMSC or BMP-7 alone in the
healing of femoral defects in rats. Further studies with larger samples are required to confirm these results and to evaluate
the best dosage. 相似文献
60.
Objective: To further explore the mechanism of congenital pyrimidine 5'-nucleotidase I deficiency. Methods; The samples were collected from the family members of a patient with P5'N- I deficiency. The enzyme activities were measured by UMP method and the enzyme proteins were quantified by ELISA while the morphology of peripheral blood cells was observed. Results: The enzyme contents reduced as their enzyme activities decreased in the family especially in four members. There was a significant positive correlation(r =0. 955) between the activity and the content of P 5'N- I . The count of the stippling cell was varied in the family. Conclusion.- One of the reasons for congenital P5' N- I deficiency might be the deficiency in the enzyme content. The morphology of peripheral blood erythrocyte may be an assistant diagnotic index. The P5'N- I activities and contents were measured simultaneously may be a effective method in clinic diagnosis. 相似文献