全文获取类型
收费全文 | 262857篇 |
免费 | 57348篇 |
国内免费 | 12158篇 |
专业分类
耳鼻咽喉 | 2899篇 |
儿科学 | 6368篇 |
妇产科学 | 2573篇 |
基础医学 | 41165篇 |
口腔科学 | 8191篇 |
临床医学 | 35205篇 |
内科学 | 47637篇 |
皮肤病学 | 9221篇 |
神经病学 | 21530篇 |
特种医学 | 8565篇 |
外国民族医学 | 82篇 |
外科学 | 31334篇 |
综合类 | 33408篇 |
现状与发展 | 40篇 |
一般理论 | 34篇 |
预防医学 | 17651篇 |
眼科学 | 5777篇 |
药学 | 27024篇 |
173篇 | |
中国医学 | 12454篇 |
肿瘤学 | 21032篇 |
出版年
2024年 | 783篇 |
2023年 | 3090篇 |
2022年 | 7884篇 |
2021年 | 10964篇 |
2020年 | 12006篇 |
2019年 | 16338篇 |
2018年 | 16042篇 |
2017年 | 16920篇 |
2016年 | 17167篇 |
2015年 | 19712篇 |
2014年 | 21539篇 |
2013年 | 21573篇 |
2012年 | 18040篇 |
2011年 | 18615篇 |
2010年 | 18860篇 |
2009年 | 13408篇 |
2008年 | 11925篇 |
2007年 | 10990篇 |
2006年 | 10238篇 |
2005年 | 9198篇 |
2004年 | 7418篇 |
2003年 | 7502篇 |
2002年 | 6637篇 |
2001年 | 5705篇 |
2000年 | 4808篇 |
1999年 | 3932篇 |
1998年 | 2271篇 |
1997年 | 2460篇 |
1996年 | 1738篇 |
1995年 | 1654篇 |
1994年 | 1443篇 |
1993年 | 990篇 |
1992年 | 1280篇 |
1991年 | 1129篇 |
1990年 | 981篇 |
1989年 | 891篇 |
1988年 | 781篇 |
1987年 | 707篇 |
1986年 | 629篇 |
1985年 | 502篇 |
1984年 | 418篇 |
1983年 | 333篇 |
1982年 | 285篇 |
1981年 | 248篇 |
1980年 | 203篇 |
1979年 | 211篇 |
1978年 | 193篇 |
1977年 | 211篇 |
1976年 | 191篇 |
1974年 | 156篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Inhibitory effects of licochalcone A isolated from Glycyrrhiza inflata root on inflammatory ear edema and tumour promotion in mice 总被引:1,自引:0,他引:1
S Shibata H Inoue S Iwata R D Ma L J Yu H Ueyama J Takayasu T Hasegawa H Tokuda A Nishino 《Planta medica》1991,57(3):221-224
Licochalcone A, 3-a,a-dimethylallyl-4,4'-dihydroxy-6-methoxychalcone, from the root of Glycyrrhiza inflata Beta (Leguminosae) (Xin-jiang liquorice) showed anti-inflammatory action towards mouse ear edema induced by arachidonic acid (AA) and 12-O-tetradecanoylphorbol 13-acetate (TPA) by topical application. Anti-tumour promoting action of licochalcone A was also observed in vivo for mouse skin papilloma initiated by dimethylbenz[a]anthracene (DMBA) and promoted by TPA. It inhibited in vitro 32Pi-incorporation to phospholipids in HeLa cells promoted by TPA. A competitive interaction of licochalcone A with the TPA-receptors in the cell membrane has been suggested. 相似文献
992.
Weikai Xue Jonas Ogien Pavel Bulkin Anne-Lise Coutrot Arnaud Dubois 《Journal of biomedical optics》2022,27(8)
SignificanceLine-field confocal optical coherence tomography (LC-OCT) is a recently introduced high-resolution imaging modality based on a combination of low-coherence optical interferometry and reflectance confocal optical microscopy with line illumination and line detection. Capable of producing three-dimensional (3D) images of the skin with cellular resolution, in vivo, LC-OCT has been mainly applied in dermatology and dermo-cosmetology. The LC-OCT devices capable of acquiring 3D images reported so far are based on a Linnik interferometer using two identical microscope objectives. In this configuration, LC-OCT cannot be designed to be a very compact and light device, and the image acquisition speed is limited.AimThe objective of this work was to develop a more compact and lighter LC-OCT device that is capable of acquiring images faster without significant degradation of the resolution and with optimized detection sensitivity.ApproachWe developed an LC-OCT device based on a Mirau interferometer using a single objective. Dynamic adjustment of the camera frequency during the depth scan is implemented, using a faster camera and a more powerful light source. The reflectivity of the beam-splitter in the Mirau interferometer was optimized to maximize the detection sensitivity. A galvanometer scanner was incorporated into the device for scanning the illumination line laterally. A stack of adjacent B-scans, constituting a 3D image, can thus be acquired.ResultsThe device is able to acquire and display B-scans at 17 fps. 3D images with a quasi-isotropic resolution of (1.3, 1.9, and in the , and directions, respectively) over a field of () can be obtained. 3D imaging of human skin at cellular resolution, in vivo, is reported.ConclusionsThe acquisition rate of the B-scans, at 17 fps, is unprecedented in LC-OCT. Compared with the conventional LC-OCT devices based on a Linnik interferometer, the reported Mirau-based LC-OCT device can acquire B-scans times faster. With potential advantages in terms of compactness and weight, a Mirau-based device could easily be integrated into a smaller and lighter handheld probe for use by dermatologists in their daily medical practice. 相似文献
993.
Shengyu Fang Lianwang Li Shimeng Weng Zhong Zhang Xing Fan Tao Jiang Yinyan Wang 《Human brain mapping》2022,43(13):3958
Supplementary motor area (SMA) syndrome is a surgery‐related complication that commonly occurs after removing SMA glioma, and needs weeks to recover. However, susceptible factors of patients suffering from SMA syndrome remain unknown. Graphic theory was applied to reveal topological properties of sensorimotor network (SMN) by processing resting‐state functional magnetic resonance images in 66 patients with SMA gliomas. Patients were classified into SMA and non‐SMA groups based on whether they suffered from SMA syndrome. We collected recovery time and used causal mediation analysis to find association between topological properties and recovery time. Compared with the non‐SMA group, higher vulnerability (left: p = .0018; right: p = .0033) and lower fault tolerance (left: p = .0022; right: p = .0248) of the whole SMN were found in the SMA group. Moreover, higher nodal properties of lesional‐hemispheric cingulate cortex (nodal efficiency: left, p = .0389; right, p = .0169; nodal vulnerability: left, p = .0185; right, p = .0085) and upper limb region of primary motor cortex (PMC; nodal efficiency: left, p = .0132; right, p = .0001; nodal vulnerability: left, p = .0091; right, p = .0209) were found in the SMA group. Nodal efficiency and nodal vulnerability of cingulate cortex and upper limb region of PMC were important predictors for SMA syndrome occurring and recovery time prolonging. Neurosurgeons should carefully deal with upper limb region of PMC and cingulate cortex, and protect them if these two region were unnecessary to damage during SMA glioma resection. 相似文献
994.
目的 观察胃癌组织中 p16基因的表达和增殖细胞核抗原 (PCNA)染色强度指数间的关系及临床意义。方法 采用LSAB免疫组织化学法。结果 在 34例原发性胃癌组织中 ,p16基因阳性表达率4 7 0 6 % (16 / 34) ,PCNA染色指数平均为 5 9 2 8± 3 4 8,p16基因阳性率和PCNA染色指数在组织学分级Ⅰ级中明显低于组织学分级Ⅲ级 (均P <0 0 5 ) ;在无淋巴结转移者中明显低于有淋巴结转移者 (分别为P <0 0 5 ,P <0 0 1)。结论 胃癌组织中 p16基因的表达和PCNA染色指数与胃癌的发生、发展密切相关 ,可以客观反映胃癌的组织分化状态、肿瘤进展及转移潜力 相似文献
995.
Inhibitory effect of topiramate on Lewis lung carcinoma metastasis and its relation with AQP1 water channel 总被引:13,自引:0,他引:13
AIM: To study the effect of topiramate on tumor metastasis and its relation with aquaporin 1 (AQP1) water channel. METHODS: Lewis lung carcinoma metastatic model was used to determine the effect of topiramate on tumor growth and metastasis. Colorimetric estimation was used to investigate the action of topiramate on carbonic anhydrase (CA) activity. Western blotting and immunohistochemical analysis were used to study the influence of topiramate on AQP1 water channel expression in lungs or tumor tissues of mice bearing Lewis lung carcinoma. 相似文献
996.
胰头肿块型慢性胰腺炎12例诊治分析 总被引:2,自引:1,他引:2
目的分析胰头肿块型胰腺炎的诊治方法。方法回顾性分析我院1998年6月至2008年6月间收治的125例慢性胰腺炎病例,总结其中12例因胰头占位而行胰十二指肠切除术患者的病例。结果12例患者术中探查均显示肿块位于胰头,与周围组织有粘连,其中1例与门静脉有粘连,但尚能剥离,术后病理证实均为慢性胰腺炎。结论目前区分慢性胰腺炎与胰腺癌尚无特异性好和敏感性高的鉴别方法,CT结合经内镜逆行胰胆管造影对大部分病例的鉴别诊断具有较高的价值,胰头肿块型胰腺炎行胰头十二指肠切除术治疗效果良好。 相似文献
997.
998.
目的:测定脓毒血症鼠Peyer小结内滤泡辅助性T细胞(T follicular helper,Tfh)的变化,分析地塞米松(dexamethasone,Dex)对脓毒血症Tfh细胞的可能作用。方法:昆明小鼠诱导脓毒血症模型,模型诱导成功后随机分2组,脓毒血症组(SE组,n=12)、脓毒血症+Dex处理组(DE组,n=12)。另设对照组(NC组,n=12)。测定血清白介素-6(interleukin-6,IL-6)、降钙素原(procalcitonin,PCT)、中性粒细胞明胶酶相关载脂蛋白(neutrophil gelatinase-associated lipocalin,NGAL)水平。Peyer小结Ⅰ型1-磷酸鞘氨醇(Sphingosine 1-Phosphate 1,S1P1)、CXC趋化因子配体13(CXC chemokine ligand 13,CXCL13)免疫组化染色。Western blot分别检测Peyer小结IL-21、程序性死亡分子-1(programmed death 1,PD-1)、胞嘧啶脱氨酶(enzyme activation-induced cytidine deaminase,AID)蛋白的表达。流式细胞仪测定3组Peyer小结Tfh细胞占T淋巴细胞的百分率。结果:与NC组相比,SE组血清IL-6(19.7±5.20 vs 10.7±3.60 ng·L~(-1))、PCT(1.56±0.92 vs 0.31±0.09μg·L~(-1))、NGAL(0.44±0.11 vs 0.35±0.09 mg·L(-1))升高(P〈0.05或0.01),Peyer小结S1P1(0.22±0.06 vs 0.14±0.04)、CXCL13(0.25±0.07 vs 0.15±0.04)的表达增加(P〈0.01),IL-21(0.60±0.08 vs 0.35±0.08)、PD-1(0.30±0.04 vs 0.20±0.05)、AID(0.23±0.05 vs 0.18±0.03)蛋白的表达亦升高(P〈0.05或0.01),Tfh细胞占T淋巴细胞(8.30±2.00 vs 5.69 vs 1.64%)的百分率升高(P〈0.01)。Dex治疗可降低SE鼠血清IL-6(19.7±5.20 vs 12.8±3.40 ng·L~(-1))、PCT(1.56±0.92 vs 0.71±0.44μg·L~(-1))水平(P〈0.05或0.01),降低Peyer小结S1P1(0.22±0.06 vs 0.17±0.05)、CXCL13(0.25±0.07 vs 0.19±0.06)的表达(P〈0.05或0.01),下调Peyer小结IL-21(0.60±0.08 vs 0.48±0.09)、PD-1(0.30±0.04 vs 0.26±0.06)、AID(0.23±0.05 vs0.19±0.04)蛋白的表达(P〈0.05),降低Tfh细胞占T淋巴细胞(8.30±2.00 vs 6.56±1.59%)的百分率(P〈0.05)。结论:Peyer小结Tfh细胞可能参与脓毒血症的发病机制,Dex抑制Peyer小结Tfh的活化,对Peyer小结微环境起保护作用。 相似文献
999.
Chanthakan Nuchsuk Nuanchawee Wetprasit Sittiruk Roytrakul Kiattawee Choowongkomon Nattanan T‐Thienprasert Chotika Yokthongwattana Theerakul Arpornsuwan Sunanta Ratanapo 《Chemical biology & drug design》2013,82(4):453-462
In this study, a type 1 RIP, designated as Jc‐SCRIP, was first isolated from the seed coat of Jatropha curcas Linn. It was purified by ammonium sulfate precipitation and chromatography on DEAE‐Sephacel? and CM‐cellulose columns. Purification fold of Jc‐SCRIP increased 113.8 times, and the yield was 1.13% of the total protein in the final step. It was shown to be a monomeric glycoprotein with a molecular mass of 38 938 Da, as determined by MALDI‐TOF/MS. It exhibited hemagglutination activity and possessed strong N‐glycosidase activity. The antimicrobial activity of Jc‐SCRIP was tested against nine human pathogenic bacteria and one fungus; the most potent inhibitory activity was against Staphylococcus epidermidis ATCC 12228, with minimum inhibitory concentration value of 0.20 μm . Jc‐SCRIP demonstrated in vitro cytotoxicity against human breast adenocarcinoma cell line (MCF‐7), a colon adenocarcinoma (SW620), and a liver carcinoma cell line (HepG2), with IC50 values of 0.15, 0.25, and 0.40 mm , respectively. The results suggested that Jc‐SCRIP may be a potential natural antimicrobial and anticancer agent in medical applications. 相似文献
1000.
Based on numerical shape functions and the structural stressing state theory, the mechanical properties of the curved prestressed concrete box girder (CPCBG) bridge model under different loading cases are presented. First, the generalized strain energy density (GSED) obtained from the measured strain data is used to represent the stressing state pattern of the structure; then, the stressing state of the concrete section is analyzed by plotting the strain and stress fields of the bridge model. The stressing state pattern and strain fields of the CPCBG are shown to reveal its mechanical properties. In addition, the measured concrete strain data are interpolated by the non-sample point interpolation (NPI) method. The strain and stress fields of the bridge model have been plotted to analyze the stressing state of the concrete cross-section. The internal forces in the concrete sections are calculated by using interpolated strains. Finally, the torsional effects are simulated by measuring the displacements to show the torsional behavior of the cross-section. The analysis and comparison of the internal force and strain fields reveal the common and different mechanical properties of the bridge model. The results of the analysis of the curved bridge model provide a reference for the future rational design of bridge projects. 相似文献