全文获取类型
收费全文 | 5605篇 |
免费 | 299篇 |
国内免费 | 193篇 |
专业分类
耳鼻咽喉 | 38篇 |
儿科学 | 91篇 |
妇产科学 | 91篇 |
基础医学 | 1341篇 |
口腔科学 | 82篇 |
临床医学 | 393篇 |
内科学 | 1095篇 |
皮肤病学 | 108篇 |
神经病学 | 485篇 |
特种医学 | 96篇 |
外科学 | 404篇 |
综合类 | 669篇 |
预防医学 | 167篇 |
眼科学 | 40篇 |
药学 | 494篇 |
1篇 | |
中国医学 | 149篇 |
肿瘤学 | 353篇 |
出版年
2023年 | 41篇 |
2022年 | 102篇 |
2021年 | 117篇 |
2020年 | 100篇 |
2019年 | 217篇 |
2018年 | 240篇 |
2017年 | 174篇 |
2016年 | 116篇 |
2015年 | 134篇 |
2014年 | 455篇 |
2013年 | 314篇 |
2012年 | 305篇 |
2011年 | 387篇 |
2010年 | 371篇 |
2009年 | 373篇 |
2008年 | 380篇 |
2007年 | 348篇 |
2006年 | 275篇 |
2005年 | 221篇 |
2004年 | 182篇 |
2003年 | 166篇 |
2002年 | 129篇 |
2001年 | 99篇 |
2000年 | 93篇 |
1999年 | 81篇 |
1998年 | 67篇 |
1997年 | 54篇 |
1996年 | 66篇 |
1995年 | 71篇 |
1994年 | 33篇 |
1993年 | 31篇 |
1992年 | 18篇 |
1991年 | 18篇 |
1990年 | 8篇 |
1989年 | 15篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 56篇 |
1984年 | 29篇 |
1983年 | 40篇 |
1982年 | 33篇 |
1981年 | 25篇 |
1980年 | 22篇 |
1979年 | 24篇 |
1978年 | 15篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1973年 | 5篇 |
排序方式: 共有6097条查询结果,搜索用时 15 毫秒
61.
Total hip replacement has become one of the most successful surgical operations over the past 25 years. The duration of a total hip prosthesis depends on primary stability, and many studies have tried precisely to evaluate hip joint morphology to obtain excellent contact between bone and prosthetic component. This study performed a morphometric analysis of the human hip joint using, for the first time, the P40 plastination procedure. We cut 42 hip joint compounds into slices 3 mm thick; for exact distance measuring the sections were scanned into the computer. The following mean measurements for hip geometry were obtained: vertical diameter of acetabulum 4.894±0.274 cm, depth of acetabulum 1.643±0.245 cm, femoral head radius 2.268±0.149 cm, femoral neck length 4.3670±0.528 cm, acetabular perimeter 6.711±0.434 cm, vertical diameter of labrum acetabulare 4.759±0.476 cm, depth of labrum acetabulare 2.599±0.395 cm, sum of femoral head and neck lengths 6.759±0.550 cm, hip axis length 11.859±1.007 cm, femoral neck axis length 10.12±0.555 cm, and femoral neck diameter 3.349±0.276 cm. All of these data reveal a significant gender difference. Our aim was to indicate an unconventional and new method of gaining morphometric hip data by using plastination. 相似文献
62.
目的 :观察九钨三钛硅酸盐 ( α- K8H2 〔Si W9Ti3 O4 0 〕· 1 5H2 O,简称 α- Ti3 )孕期给药对大鼠胎仔的毒性影响。方法 :大鼠孕期以 57.0 9,1 71 .2 8和 51 3.83mg/ kg剂量经口给予α- Ti3 ,并以Vit A为阳性对照及蒸馏水为阴性对照 ,产前剖腹检测胎鼠生长发育指标、外观内脏骨骼形态等。结果 :三个剂量组均未见胎鼠外观、内脏及骨骼畸形。低剂量组与高剂量组的活胎率升高 ,吸收胎数下降 ,与阴性对照组比较有显著性差异 (均为 P<0 .0 5)。低、中、高剂量组的胎鼠体重和身长高于阴性对照组 (分别为 P<0 .0 5,P<0 .0 1 ,P<0 .0 1 ) ,且增长程度与剂量呈正相关 ( r=0 .840 8,0 .72 2 8,P<0 .0 0 5,0 .0 5)。低、中、高三个剂量组的上枕骨骨化程度及胸骨块数高于阴性对照组和阳性对照组 ( P<0 .0 5,0 .0 1 ,0 .0 1 ,0 .0 5和 P<0 .0 5,0 .0 1 ,0 .0 1 )。各剂量组的母鼠肝脏重量及肝体比值不同程度下降。其中 ,中、高剂量组及阳性对照组的肝重及肝体比值与阴性对照组比较差异显著 (肝重比较分别为 P<0 .0 5,P<0 .0 5和 P<0 .0 1 ,肝体比值比较均为 P<0 .0 5)。结论 :α- Ti3 致畸试验未见胎鼠畸形 ,但可提高胎鼠生长发育指标和骨骼骨化程度。 相似文献
63.
热双蒸水联用生理盐水及右旋糖酐-40预防腹腔内肿瘤种植转移的实验研究 总被引:2,自引:0,他引:2
联合应用热双蒸水、生理盐水、右旋糖酐40 序贯腹腔冲洗的方法,行体外试验与动物试验。发现45 ℃双蒸水浸泡腹腔20 min 后能完全杀灭体外培养的B6F10 细胞;右旋糖酐40 部分抑制B16F10 细胞对胶化培养板孔壁的粘附。小鼠腹腔注入B16F10 细胞后,按上述三联合液序贯冲洗可预防70 % 的C57 BL/6j小鼠发生腹膜癌病,未见毒副作用。在此冲洗的基础上,腹腔内保留氯氨铂,疗效高达88-9 % ,但毒性也增加 相似文献
64.
Rationale: Late onset type 1 alcoholism has been suggested to be associated with an underlying dopaminergic defect. Therefore, it is
relevant to study both postsynaptic D2-receptor and presynaptic dopamine transporter (DAT) densities among alcoholics. Objective: We investigated DAT densities, along with striatal and extrastriatal dopamine D2-receptor densities, in nine non-violent late-onset male alcoholics, who had no major mental disorder nor antisocial personality
disorder (ASPD), and nine healthy controls. Methods: [123I]PE2I and [123I]epidepride were used in SPECT imaging. Results: DAT occupancy ratios (striatum/cerebellum) were significantly lower among alcoholics than in controls. Extrastriatal D2-receptor occupancy ratios (temporal pole/cerebellum) were not significantly different between the groups. Conclusions: Striatal presynaptic DAT densities are decreased among type 1 alcoholics, and this finding is not associated with recent
alcohol abuse.
Received: 22 March 1999 / Final version: 25 June 1999 相似文献
65.
Deletions in the ligand for CD40 in X-linked immunoglobulin deficiency with normal or elevated IgM (HIGMX-1) 总被引:10,自引:0,他引:10
Ramesh Narayanaswamy; Fuleihan Ramsay; Ramesh Vijaya; Lederman Seth; Yellin Michael J.; Sharma Sunita; Chess Leonard; Rosen Fred S. 《International immunology》1993,5(7):769-773
Patients with X-linked Ig deficiency with normal or elevatedIgM (HIGMX-1) fail to switch from IgM/IgD to other Ig isotypes.Interaction between the B cell antigen CD40 and the CD40 ligandexpressed on activated T cells is critical for T cell drivenisotype switching. We have reported that T lymphocytes fromthree unrelated male patients with HIGMX-1 failed to expressCD40 ligand on their surface, but the mRNA for CD40 ligand wasof an apparently normal size and level. Analysis of CD40 ligandcDNA from two of the patients revealed deletions that alterthe reading frame. Patient 1 displayed two mutations: a C Atransversion at nucleotide 590 and the deletion of an adjacentC nucleotide. The second patient had a 58 bp deletion from nucleotides289–346. Furthermore, neither patient expressed a proteinproduct detectable by the CD40L mAb, 5c8. 相似文献
66.
L. C. Rump K. Wilde C. Bohmann P. Schollmeyer 《Naunyn-Schmiedeberg's archives of pharmacology》1992,345(3):300-308
Summary The effects of the classical dopamine DA2-receptor agonist quinpirole (LY 171555) and the recently characterized DA2-receptor agonist, carmoxirole (EMD 45609), on neurotransmission in rat isolated kidney were investigated. After preincubation with 3H-noradrenaline, the renal nerves were electrically stimulated. The stimulation induced (S-I) outflow of radioactivity was taken as an index of noradrenaline release. Quinpirole (0.3 mol/l) inhibited S-I outflow of radioactivity and pressor responses to renal nerve stimulation (RNS) at 1 Hz. Both effects of quinpirole were blocked by the DA2-receptor antagonist S(–)-sulpiride (10 mol/l). The 1, 2-adrenoceptor antagonist phentolamine (1 mol/l) did not block the inhibitory effect of quinpirole. Carmoxirole (0.003 and 0.03 mol/l) did not alter and carmoxirole (0.3 mol/l) even enhanced S-I outflow of radioactivity, however, pressor responses to RNS were markedly reduced by carmoxirole (0.003–0.3 mol/l). Pressor responses to RNS were also markedly reduced by the 1-adrenoceptor antagonist prazosin (0.1 mol/l). Carmoxirole (0.3 mol/l), prazosin (0.1 mol/l) and phentolamine (1 mol/l) totally abolished pressor responses to exogenous noradrenaline (0.05 mol/l). In contrast, quinpirole (0.3 mol/l) did not alter pressor responses to exogenous noradrenaline (0.05 mol/l). Furthermore, carmoxirole (0.003–0.3 mol/l) markedly reduced pressor responses induced by the 1-adrenoceptor agonist methoxamine (1 mol/l) but even the highest concentration of carmoxirole (0.3 mol/l) had no effect on pressor responses induced by bolus injections of either neuropeptide Y (1.5 ng) or angiotensin II (1 ng). Phentolamine (1 mol/l) by itself markedly enhanced S-1 outflow of radioactivity and pressor responses to RNS were virtually unchanged. In the presence of phentolamine carmoxirole (0.03 and 0.3 mol/l) and quinpirole inhibited S-I outflow of radioactivity and pressor responses to RNS. Phentolamine resistant pressor responses to RNS were also inhibited by the P2X-receptor desensitizing agent , -methylene adenosine triphosphate (mATP, 1 mol/l), which by itself in the presence of phentolamine did not alter S-I outflow of radioactivity. The inhibitory effects of carmoxirole (0.3 mol/l) in the presence of phentolame (1mol/l) were antagonized by S(–)-sulpiride (10 mol/l). The data suggest that activation of prejunctional DA2-receptors by quinpirole inhibits noradrenaline release and thereby reduces pressor response to RNS at 1 Hz in rat isolated kidney. Carmoxirole activates prejunctional inhibitory DA2-receptors, but this effect is masked by simultaneous blockade of inhibitory prejunctional -adrenoceptors. Pressor responses to RNS at 1 Hz in rat isolated kidney are largely due to neuronally released noradrenaline whereas phentolamine resistant pressor responses to RNS at 1 Hz are most likely due to ATP, which is co-released with noradrenaline. Carmoxirole inhibits pressor responses to RNS at 1 Hz as well as pressor responses induced by either exogenous noradrenaline or methoxamine by blocking postjunctional 1-adrenoceptors. In addition carmoxirole and quinpirole seem to block phentolamine resistant pressor responses by inhibiting ATP release through activation of prejunctional DA2-receptors.
Send offprint requests to L. C. Rump at the above address 相似文献
67.
细胞因子对人脐静脉内皮细胞表达CD40和CD40L的影响 总被引:2,自引:2,他引:2
CD40 CD40L是一对互补的跨膜糖蛋白 ,在机体免疫应答中起重要作用 ,近年来的研究表明这一对配体 -受体参与了AS的发生和发展[1] 。AS的形成与发展过程中可有多种细胞因子参与和合成多种细胞因子。本文研究细胞因子γ干扰素 (IFN γ)、肿瘤坏死因子 (TNF)、白介素 6(IL 6)和白介素 1(IL 1)对人脐静脉内皮细胞表达CD40及CD40L的影响 ,以期揭示CD40 CD40L在AS发生中的作用地位。1 材料和方法1.1 材料 IFN γ、TNF、IL 6、IL 1、CD40和CD40L单抗购自Pharmingen公司 ,鼠IgGPE… 相似文献
68.
Radetti G Bozzola M Braga V Paganini C Moretti C Adami S 《Calcified tissue international》2000,67(1):45-46
The aim of this study was to evaluate the usefulness of a major secretory protein of human chondrocytes (chondrex) as a potential serum marker
of bone responsiveness to growth hormone (GH). The study included 18 children (10 F, 8 M), aged 10.9 ± 2.3 years, bone age
8.8 ± 2.7 years, height −2.3 ± 0.22 SDS, affected by isolated idiopathic GH deficiency (GHD). Serum samples for evaluation
of chondrex, total, and bone alkaline phosphatase were taken before and 3 and 6 months following treatment with rhGH. The
basal serum level of chondrex did not differ between patients (37 ± 22 ng/ml) and controls (33 ± 9.8 ng/ml). Following 6 months
of treatment with rhGH, a significant increase of height velocity SDS (from −2.8 ± 0.5 to 1.3 ± 0.7), total (from 195 ± 47
to 264 ± 79 U/liter) and bone alkaline phosphatase (from 81 ± 21 to 108 ± 30 U/liter) was observed, while chondrex serum level
remained unchanged (from 37 ± 22 to 36 ± 29 ng/ml). It was concluded that chondrex cannot be considered a reliable marker
of bone responsiveness to GH in the growing child.
Received: 19 March 1999 / Accepted: 3 February 2000 相似文献
69.
Objective To examine the in vivo anti-metastatic effect of enhanced expression of CD40L cDNA in murinc ovarian cancer OVUM cells (CD4OL-OVHM) injected into the spleen on liver metastasis in mice. Methods OVUM cells were inoculated into the spleen of 6 ~ 8 week-old female B6C3F1 (C57BL/6N × C3H/He) mice. The established liver metastasis was identified by histopathology (HE staining). OVUM cells, DNA-pMKITneo-OVHM cells or CD40L-OVHM cells were inoculated into the spleen of female B6C3F1 mice and the expressions of CD11c in splenic cells were detected by flow cytometry. The specific cytotoxicity of splenic cells was detected by MTT assay, and the serum cytokines of IFN-γ, TNF-α, IL-12, IL4 and IL-10 of the mice were measured by enzyme linked immunoabsorbent assay. The liver metastases and the survival time of the mice were also recorded. Results The mouse models with liver metastasis by injecting tumor cells into the spleen of mice were established. The expression of CD11c and the specific killing rote in CD40L-OVHM cells group was significantly higher than that in the OVHM cells group and DNA-pMKITneo-OVHM cells group. The expressions of IFN-γ, TNF-α and IL-12 in the CD40L-OVHM cells group were much more increased than OVHM cells group and DNA-pMKITneo-OVHM cells group, but the expressions of IL-4 and IL-10 in the CD40L-OVHM cells group were decreased significantly (P < 0.05). The average weights of livers and spleens of mice in CD40L-OVHM cells group were significantly lower than those of DNA-pMKITneo-OVHM cells group and OVHM cells group. The survival time of mice in CD40L-OVHM cells group was also significantly longer than that in the OVHM cells group and DNA-pMKITneo-OVHM cells group (P < 0.05). Conclusion The data directly demonstrate that the expression of CD40L in ovarian cancer cells (CD40L-OVHM) can enhance the proliferation and differentiation of dendritic cells in the spleen and induce specific cytotoxic effect of T cells in the spleen, and may regulate the immune function of peripheral blood cells and the immune balance between Thl cells and Th2 cells, which maybe the possible mechanism induced by CD40L in mice inhibiting the development of liver metastasis. 相似文献
70.
N Laytragoon-Lewin 《Medical oncology (Northwood, London, England)》1998,15(1):15-19
Programmed cell death (PCD) or apoptosis is a process whereby developmental or environmental stimuli activate a specific series
of events that culminate in cell death. PCD is essential for normal development and abnormality in the process can lead to
defects ranging from embryonic lethality and tissue-specific perturbation of postnatal development to a high susceptibility
to malignancy. Therapeutics that modulate the regulation of PCD may provide a new opportunity for the treatment of the PCD
related diseases and cancer. CD40 and CD95 (Fas/Apo-I) are transmembrane proteins of the nerve growth factor/tumour necrosis
factor α receptor superfamily. The death signal of PCD occurs when the CD95 receptor on the cell surface binds to the CD95
ligand (CD95L) or to the anti-CD95 monoclonal antibody (mAb). In contrast, PCD could be inhibited by the survival signal mediated
from the binding of the CD40 receptor to the CD40 ligand (CD40L) or to the anti-CD40 mAb. In this review, the interaction
of CD40/CD40L and CD95/CD95L on PCD in normal and malignant cells is discussed. 相似文献