全文获取类型
收费全文 | 92629篇 |
免费 | 8966篇 |
国内免费 | 6172篇 |
专业分类
耳鼻咽喉 | 956篇 |
儿科学 | 879篇 |
妇产科学 | 931篇 |
基础医学 | 10673篇 |
口腔科学 | 1694篇 |
临床医学 | 11536篇 |
内科学 | 13442篇 |
皮肤病学 | 1176篇 |
神经病学 | 4623篇 |
特种医学 | 4098篇 |
外国民族医学 | 47篇 |
外科学 | 10715篇 |
综合类 | 15657篇 |
现状与发展 | 20篇 |
一般理论 | 4篇 |
预防医学 | 6384篇 |
眼科学 | 2392篇 |
药学 | 9707篇 |
78篇 | |
中国医学 | 5336篇 |
肿瘤学 | 7419篇 |
出版年
2024年 | 349篇 |
2023年 | 1603篇 |
2022年 | 4099篇 |
2021年 | 5232篇 |
2020年 | 3787篇 |
2019年 | 3195篇 |
2018年 | 3347篇 |
2017年 | 3053篇 |
2016年 | 3013篇 |
2015年 | 4473篇 |
2014年 | 5464篇 |
2013年 | 5235篇 |
2012年 | 7724篇 |
2011年 | 8098篇 |
2010年 | 5472篇 |
2009年 | 4444篇 |
2008年 | 5366篇 |
2007年 | 5207篇 |
2006年 | 4734篇 |
2005年 | 4321篇 |
2004年 | 3000篇 |
2003年 | 2653篇 |
2002年 | 2300篇 |
2001年 | 1819篇 |
2000年 | 1783篇 |
1999年 | 1678篇 |
1998年 | 889篇 |
1997年 | 939篇 |
1996年 | 752篇 |
1995年 | 636篇 |
1994年 | 520篇 |
1993年 | 330篇 |
1992年 | 419篇 |
1991年 | 333篇 |
1990年 | 294篇 |
1989年 | 243篇 |
1988年 | 201篇 |
1987年 | 164篇 |
1986年 | 133篇 |
1985年 | 101篇 |
1984年 | 68篇 |
1983年 | 52篇 |
1982年 | 33篇 |
1981年 | 34篇 |
1980年 | 14篇 |
1979年 | 29篇 |
1978年 | 22篇 |
1974年 | 12篇 |
1973年 | 15篇 |
1971年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Weiping Ren Bin Wu Xin Peng Jing Hua Hsiao-Nan Hao Paul H Wooley 《Journal of orthopaedic research》2006,24(8):1575-1586
Signaling of RANK (receptor activator of nuclear factor kappa B) through its ligand RANKL appears critical in osteolysis associated with aseptic loosening (AL). The purpose of this study was to investigate the role of RANK in a murine osteolysis model developed in RANK knockout (RANK(-/-)) mice. Ultra high molecular weight polyethylene (UHMWPE) debris was introduced into established air pouches on RANK(-/-) mice, followed by implantation of calvaria bone from syngeneic littermates. Wild type C57BL/6 (RANK(+/+)) mice injected with either UHMWPE or saline alone were included in this study. Pouch tissues were collected 14 days after UHMWPE inoculation for molecular and histology analysis. Results showed that UHMWPE stimulation induced strong pouch tissue inflammation in RANK(-/-) mice, as manifested by inflammatory cellular infiltration, pouch tissue proliferation, and increased gene expression of IL-1beta, TNFalpha, and RANKL. However, the UHMWPE-induced inflammation in RANK(-/-) mice was not associated with the osteoclastic bone resorption observed in RANK(+/+) mice. In RANK(+/+) mice subjected to UHMWPE stimulation, a large number of TRAP(+) cells were found on the implanted bone surface, where active osteoclastic bone resorption was observed. No TRAP(+) cells were found in UHMWPE-containing pouch tissues of RANK(-/-) mice. Consistent with the lack of osteoclastic activity shown by TRAP staining, no significant UHMWPE particle-induced bone resorption was found in RANK(-/-) mice. A well preserved bone collagen content (Van Gieson staining) and normal plateau surface contour [microcomputed tomography (microCT)] of implanted bone was observed in RANK(-/-) mice subjected to UHMWPE stimulation. In conclusion, this study provides the evidence that UHMWPE particles induce strong inflammatory responses, but not associated with osteoclastic bone resorption in RANK(-/-) mice. This indicates that RANK signaling is essential for UHMWPE particle-induced osteoclastic bone resorption, but does not participate in UHMWPE particle-induced inflammatory response. 相似文献
5.
郝建新 《北京中医药大学学报(中医临床版)》2002,9(1):34-37
上世纪末曾有人提出我国的中药产业将成为本世纪的“朝阳产业”,口号甚是鼓舞人心。但结合我国中药产业的现状分析,却不容乐观。想在本世纪的头几年达到蓬勃兴盛的状态可能还有很大差距。问题在哪里,笔者以为,除了中药生产企业本身存在诸多问题外,关键还在于针对中药学本身的现代研究没有取得明显的突破性进展。以致我国有关中药研发的政策、法 相似文献
6.
M K Song W Y Shin N F Adham N V Costea 《The American journal of clinical nutrition》1989,49(4):701-707
The effects of different amounts of dietary zinc on the Zn absorption rate and on Zn, calcium and magnesium concentrations in tissues of MOPC 104E tumor-bearing Balb/c mice were determined. The Zn absorption rate was inversely related to the amounts of Zn in their diets and was lower than that of nontumor-bearing control mice fed a laboratory mice chow. Zn concentrations of tumor-bearing mice were also low compared with control mice but tumor Zn concentrations, regardless of the concentrations of Zn in the diets, were higher than those of normal tissues of the host other than the pancreas. Ca concentrations in tumor and tissues of tumor-bearing mice were higher than in control animals but Mg concentrations in tissues of tumor-bearing mice appeared to be similar to those of control mice. Results suggest that tumor-bearing mice have a lower intestinal Zn absorption capacity and a higher Zn uptake rate causing other tissues to become hypozincemic and hypercalcemic. 相似文献
7.
In order to clarify the reported discrepancies in S100 alpha protein and mRNA distribution in rat tissues, a rat S100 alpha cDNA has been isolated and this species homologous probe along with a rat S100 beta cDNA probe has been used to examine S100 mRNA expression in rat tissues. Although the rat S100 alpha cDNA was missing approximately 30 nucleotides of coding sequence, only 4 conservative changes in amino acid sequence were observed when the deduced amino acid sequence was compared to the bovine S100 alpha amino acid sequence. Thus, S100 alpha proteins, like S100 beta proteins, are highly conserved among species. All nineteen of the tissues examined (including cerebrum and cerebellum) contained S100 alpha mRNA. In addition, S100 beta mRNA was detected in thirteen of the nineteen tissues examined. These results are in agreement with previous protein distribution studies and further demonstrate that S100 proteins are not brain-specific and are expressed in a large number of tissues. Although S100 alpha and S100 beta mRNAs were detected in rat tissues which had previously been reported to contain S100 alpha and S100 beta protein, a direct correlation between the protein and mRNA levels were not observed, suggesting that different mechanisms regulate S100 expression in various tissues. S100 alpha exhibited a single similar size mRNA species (0.5 Kb) in all tissues examined, as did S100 beta (1.5 Kb), suggesting that the individual S100 proteins are expressed as single mRNA and protein products in rat tissues. 相似文献
8.
X Dong M He X Song B Lu Y Yang S Zhang N Zhao L Zhou Y Li X Zhu R Hu 《Diabetic medicine》2007,24(12):1482-1486
AIMS: Our aim was to assess performances of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks. METHODS: A total of 1009 patients with Type 2 diabetes were categorized into low estimated GFR groups (GFR < 60 ml/min/1.73 m(2)) and control groups by the two equations. The performances of these formulae were assessed at different stages of kidney function. Carotid artery intima-media thickness (IMT) and the prevalence of diabetic retinopathy or albuminuria were compared among the groups. The ability of these formulae to identify established vascular risk markers using sensitivity, specificity, positive and negative predictive values were also compared. RESULTS: The prevalence of low estimated GFR was 32.7% with the Cockcroft-Gault formula and 5.2% with the MDRD formula, respectively. In low estimated GFR subjects by the MDRD formula, IMT was significantly thicker than those by the Cockcroft-Gault formula (1.2 mm vs. 1.0 mm; P < 0.05), with a higher prevalence of albuminuria (78.4 vs. 52.8%, P < 0.05) and diabetic retinopathy (46.5 vs. 30.5%; P < 0.05). The Cockcroft-Gault formula gave a specificity of 71.7% and a sensitivity of 37.0%, and the MDRD formula gave a specificity of 96.6% and a sensitivity of 7.9% in estimating low GFR relevant for established vascular risks. CONCLUSIONS: These formulae performed differently in Chinese diabetic populations. The simplified MDRD formula is minimally superior to the Cockcroft-Gault formula for its high specificity and positive predictive values in estimating low GFR relevant for vascular risks. 相似文献
9.
目的研究云南白药在围术期对全髋关节置换术术中出血量及术后引流量的影响。方法2006至2008年我科收治的股骨颈骨折行全髋关节置换术60例,随机分成两组,分别服用云南白药胶囊和空胶囊;术前术后测定凝血酶原时间(PT),记录全部病人术中出血量及术后24 h引流量。结果实验组和对照组病人的凝血酶原时间(PT)差异有统计学意义(P<0.01);试验组的术中出血量、术后24 h引流量分别为(380±78)ml(、336±77)ml,较对照组(481±77)ml(、418±68)ml明显减少,差异具有统计学意义(P<0.01)。结论云南白药胶囊能够明显减少全髋关节置换术围术期出血量。 相似文献
10.