全文获取类型
收费全文 | 3600篇 |
免费 | 382篇 |
国内免费 | 196篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 54篇 |
妇产科学 | 23篇 |
基础医学 | 579篇 |
口腔科学 | 32篇 |
临床医学 | 472篇 |
内科学 | 681篇 |
皮肤病学 | 72篇 |
神经病学 | 269篇 |
特种医学 | 116篇 |
外国民族医学 | 1篇 |
外科学 | 404篇 |
综合类 | 326篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 274篇 |
眼科学 | 99篇 |
药学 | 270篇 |
中国医学 | 131篇 |
肿瘤学 | 353篇 |
出版年
2024年 | 8篇 |
2023年 | 82篇 |
2022年 | 168篇 |
2021年 | 168篇 |
2020年 | 129篇 |
2019年 | 135篇 |
2018年 | 133篇 |
2017年 | 101篇 |
2016年 | 109篇 |
2015年 | 158篇 |
2014年 | 182篇 |
2013年 | 161篇 |
2012年 | 243篇 |
2011年 | 270篇 |
2010年 | 158篇 |
2009年 | 176篇 |
2008年 | 223篇 |
2007年 | 203篇 |
2006年 | 218篇 |
2005年 | 181篇 |
2004年 | 115篇 |
2003年 | 120篇 |
2002年 | 102篇 |
2001年 | 70篇 |
2000年 | 53篇 |
1999年 | 65篇 |
1998年 | 58篇 |
1997年 | 42篇 |
1996年 | 43篇 |
1995年 | 36篇 |
1994年 | 22篇 |
1993年 | 17篇 |
1992年 | 40篇 |
1991年 | 19篇 |
1990年 | 28篇 |
1989年 | 23篇 |
1988年 | 19篇 |
1987年 | 22篇 |
1986年 | 14篇 |
1985年 | 19篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1971年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有4178条查询结果,搜索用时 0 毫秒
71.
72.
大鼠脂肪条带结构针刺镇痛效应特异性的生物学基础 总被引:2,自引:2,他引:0
目的:观察大鼠脂肪条带结构针刺镇痛效应特异性的生物学基础。方法:选择大鼠胃经沿线脂肪条带结构上后三里以及脂肪条带结构旁两个对照位点(A1、A2),分别进行针刺,针刺结束后立即断头处死,分离出胃经沿线脂肪条带结构,制备匀浆液,采用放免法测定样本中的β内啡肽(βEP)、强啡肽A(DynA)、P物质(SP)含量。结果:βEP针刺后三里(19.08±7.42)与针刺A1、A2位点(2.27±1.99)经成组t检验比较,两者差异显著(t=5.5374,P<0.01)。DynA针刺后三里(23.08±8.61)与针刺A1、A2位点(2.19±1.81)经成组t检验比较,两者差异显著(t=5.8194,P<0.01);SP针刺后三里(1.57±0.49)与针刺A1、A2位点(1.05±0.60)经成组t检验比较,两者差异不显著(t=1.6330,P>0.05)。结论:针刺正常大鼠后三里腧穴,可使胃经沿线脂肪条带结构上特异性针刺镇痛效应物质βEP、DynA含量升高。 相似文献
73.
Dandan Luo Huaxuan Wen Guiyan Peng Yi Lin Meiling Liang Yimei Liao Yue Qin Qing Zeng Jing Dang Shengli Li 《Ultrasound in medicine & biology》2021,47(8):2258-2265
This study was aimed at evaluating the performance of the innovative technique Smart Fetus (SF) developed to recognize the planes and obtain the basic biometric measurements of fetuses automatically. This prospective study included 1005 uncomplicated singleton pregnancies undergoing routine examinations. For every pregnancy, planes, including the transverse section of the thalami, transverse section of the abdomen and longitudinal section of the femur, were acquired, and standard biometric measurements, including biparietal diameter, head circumference, abdominal circumference and femur length, were obtained using SF and traditional ultrasound technique (TUT). The accuracy, reproducibility and time required for the analysis of SF were compared with those of TUT. In 998 of 1005 cases (99.30%), SF successfully acquired the sections and made all measurements. The agreement between the techniques was high for all measurements. The time to obtain sections and measure biometric parameters or solely measure biometric parameters was significantly shorter with SF than with TUT. No significant differences were found in SF repeated measurements obtained by two independent observers. The SF technique helped in the acquisition of reliable standard sections and biometric measurements and saved time. It might serve as a novel ultrasound scanning approach and improve workflow efficiency. 相似文献
74.
Notch signaling plays an essential role in development as well as cancer. We have previously shown that Notch3 is important for lung cancer growth and survival. Notch receptors are activated through the interaction with their ligands, resulting in proteolytic cleavage of the receptors. This interaction is modulated by Fringe, a family of fucose-specific β1,3 N-acetylglucosaminyltransferases that modify the extracellular subunit of Notch receptors. Studies in developmental models showed that Fringe enhances Notch’s response to Delta ligands at the expense of Jagged ligands. We observed that Manic Fringe expression is down-regulated in lung cancer. Since Jagged1, a known ligand for Notch3, is often over-expressed in lung cancer, we hypothesized that Fringe negatively regulates Notch3 activation. In this study, we show that re-expression of Manic Fringe down-regulates Notch3 target genes HES1 and HeyL and reduces tumor phenotype in vitro and in vivo. The mechanism for this phenomenon appears to be related to modulation of Notch3 protein stability. Proteasome inhibition reverses Manic Fringe-induced protein turnover. Taken together, our data provide the first evidence that Manic Fringe functions as a tumor suppressor in the lung and that the mechanism of its anti-tumor activity is mediated by inhibition of Notch3 activation. 相似文献
75.
76.
Nguyen Van Quan Tran Dang Xuan Hoang-Dung Tran Ateeque Ahmad Tran Dang Khanh Tran Dang Dat 《Saudi Pharmaceutical Journal》2019,27(5):643-649
This study was the first to detect the presence of the two compounds momilactone A (MA) and momilactone B (MB) in rice bran using liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). By in vitro assays, both MA and MB exhibited potent inhibitory activities on pancreatic α-amylase and α-glucosidase which were significantly higher than γ-oryzanol, a well-known diabetes inhibitor. Remarkably, MA and MB indicated an effective inhibition on trypsin with the IC50 values of 921.55 and 884.03 µg/mL, respectively. By high-performance liquid chromatography (HPLC), quantities of MA (6.65 µg/g dry weight) and MB (6.24 µg/g dry weight) in rice bran were determined. Findings of this study revealed the α-amylase, α-glucosidase and trypsin inhibitors MA and MB contributed an active role to the diabetes inhibitory potential of rice bran. 相似文献
77.
78.
Liang Jiang Xiao Guang Liu Hui Shu Yuan Shao Min Yang Jie Li Feng Wei Chen Liu Lei Dang Zhong Jun Liu 《The spine journal》2014,14(6):944-954
Background contextVertebral hemangiomas (VHs) are called benign tumors but are actually just vascular malformations. The diagnosis and treatment for aggressive VHs is still controversial, due to their rarity.PurposeTo evaluate the safety and efficiency of the present diagnostic methods and treatment choices.Study designA retrospective study of aggressive VHs with neurologic deficit.Patients sampleA total of 29 consecutive aggressive VH cases were diagnosed and treated in our department since 2001.Outcome measuresWe routinely took anteroposterior and lateral spinal roentgenograms, computed tomography, and magnetic resonance images.MethodsTrocar biopsy is indicated in suspected malignant cases. Radiotherapy was usually our first choice if the neurologic deficit was mild or developed slowly. Surgery was indicated if the neurologic deficit was severe or developed quickly or if the radiotherapy was not effective.ResultsThis series included 12 males and 17 females, and the mean age at diagnosis was 44.0 years (range, 21–72 years). Ten patients had radiculopathy, 1 had cauda equina syndrome, and 18 cases had myelopathy. Twenty-one cases had lesions in the thoracic spine, 5 in the lumbar, and 3 in the cervical region. Eleven cases had untypical image findings, including five cases with pathologic vertebral fracture. The neurologic compression came from only epidural soft tumor mass in 18 cases, whereas it came from both bony compression and soft lesion in the other 11 cases. Ten cases had radiotherapy alone, but two failed and had surgery later. Twenty-one cases had surgery. In the 12 cases having surgical decompression without vertebroplasty, the average estimated blood loss was 1900 mL, and it was 1093 mL for the eight cases having decompression with vertebroplasty. The average follow-up was 51.1 months (range, 24–133 months). There was no recurrence in those cases with radiotherapy, whereas three had local recurrence in those six cases treated by surgical decompression alone without radiotherapy.ConclusionsIn aggressive VHs, epidural soft-tissue compression was usually the main reason for neurologic deficit. In cases with rapid progressive and/or severe myelopathy, posterior decompression and stabilization could be combined with intraoperative vertebroplasty to reduce blood loss. 相似文献
79.
Newly-found functions of metformin for the prevention and treatment of age-related macular degeneration
下载免费PDF全文
![点击此处可从《国际眼科》网站下载免费的PDF全文](/ch/ext_images/free.gif)
AIM: To explore the temporal mitochondrial characteristics of retinal pigment epithelium (RPE) cells obtained from human embryonic stem cells (hESC)-derived retinal organoids (hEROs-RPE), to verify the optimal period for using hEROs-RPE as donor cells from the aspect of mitochondria and to optimize RPE cell-based therapeutic strategies for age-related macular degeneration (AMD). METHODS: RPE cells were obtained from hEROs and from spontaneous differentiation (SD-RPE). The mitochondrial characteristics were analyzed every 20d from day 60 to 160. Mitochondrial quantity was measured by MitoTracker Green staining. Transmission electron microscopy was adopted to assess the morphological features of the mitochondria, including their distribution, length, and cristae. Mitochondrial membrane potentials (MMPs) were determined by JC-1 staining and flow cytometry. ROS levels were evaluated by flow cytometry, and ATP levels were measured by a luminometer. Differences between two groups were analyzed by the independent-samples t-test, and comparisons among multiple groups were made using one-way ANOVA or Kruskal-Wallis H test when equal variance is not assumed. RESULTS: hEROs-RPE and SD-RPE cells from day 60 to 160 were successfully differentiated from hESCs and expressed RPE-specific markers (Pax6, mitf, Bestrophin-1, RPE65, Cralbp). RPE features, including a cobblestone-like morphology with tight junctions (ZO-1), pigments and microvilli, were also observed in both hERO-RPE and SD-RPE cells. The mitochondrial quantities peaked in both hEROs-RPE and SD-RPE cells at day 80. However, the cristae of hEROs mitochondria were less mature and abundant than those of SD mitochondria at day 80, with hEROs mitochondria becoming mature at day 100. Both hEROs-RPE and SD-RPE cells showed low ROS levels from day 100 to 140 and maintained a normal MMP during this period. However, hEROs mitochondria maintained a longer time to produce high levels of ATP (from day 120 to 140) than SD-RPE cells (only day 120). CONCLUSION: Mitochondria of hEROs-RPE cells develop slower and maintain a longer time to supply high-levels of energy than SD-RPE cells. From a mitochondrial aspect, hEROs-RPE cells from day 100 to 140 are an optimal cell source for treating AMD. 相似文献
80.