全文获取类型
收费全文 | 2306篇 |
免费 | 176篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 22篇 |
儿科学 | 33篇 |
妇产科学 | 79篇 |
基础医学 | 314篇 |
口腔科学 | 63篇 |
临床医学 | 214篇 |
内科学 | 412篇 |
皮肤病学 | 13篇 |
神经病学 | 199篇 |
特种医学 | 161篇 |
外科学 | 292篇 |
综合类 | 73篇 |
预防医学 | 133篇 |
眼科学 | 52篇 |
药学 | 229篇 |
中国医学 | 28篇 |
肿瘤学 | 197篇 |
出版年
2023年 | 10篇 |
2022年 | 23篇 |
2021年 | 44篇 |
2020年 | 33篇 |
2019年 | 51篇 |
2018年 | 70篇 |
2017年 | 45篇 |
2016年 | 62篇 |
2015年 | 70篇 |
2014年 | 101篇 |
2013年 | 119篇 |
2012年 | 149篇 |
2011年 | 166篇 |
2010年 | 106篇 |
2009年 | 92篇 |
2008年 | 147篇 |
2007年 | 135篇 |
2006年 | 129篇 |
2005年 | 133篇 |
2004年 | 113篇 |
2003年 | 91篇 |
2002年 | 93篇 |
2001年 | 71篇 |
2000年 | 48篇 |
1999年 | 40篇 |
1998年 | 28篇 |
1997年 | 37篇 |
1996年 | 18篇 |
1995年 | 17篇 |
1994年 | 22篇 |
1993年 | 16篇 |
1992年 | 35篇 |
1991年 | 33篇 |
1990年 | 27篇 |
1989年 | 27篇 |
1988年 | 26篇 |
1987年 | 27篇 |
1986年 | 19篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 3篇 |
排序方式: 共有2514条查询结果,搜索用时 0 毫秒
51.
52.
53.
54.
Genghis Khan (Gek) as a putative effector for Drosophila Cdc42 and regulator of actin polymerization 下载免费PDF全文
Liqun Luo Tzumin Lee Linus Tsai Gale Tang Lily Y. Jan Yuh Nung Jan 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(24):12963-12968
The small GTPases Cdc42 and Rac regulate a variety of biological processes, including actin polymerization, cell proliferation, and JNK/mitogen-activated protein kinase activation, conceivably via distinct effectors. Whereas the effector for mitogen-activated protein kinase activation appears to be p65PAK, the identity of effector(s) for actin polymerization remains unclear. We have found a putative effector for Drosophila Cdc42, Genghis Khan (Gek), which binds to Dcdc42 in a GTP-dependent and effector domain-dependent manner. Gek contains a predicted serine/threonine kinase catalytic domain that is 63% identical to human myotonic dystrophy protein kinase and has protein kinase activities. It also possesses a large coiled-coil domain, a putative phorbol ester binding domain, a pleckstrin homology domain, and a Cdc42 binding consensus sequence that is required for its binding to Dcdc42. To study the in vivo function of gek, we generated mutations in the Drosophila gek locus. Egg chambers homozygous for gek mutations exhibit abnormal accumulation of F-actin and are defective in producing fertilized eggs. These phenotypes can be rescued by a wild-type gek transgene. Our results suggest that this multidomain protein kinase is an effector for the regulation of actin polymerization by Cdc42. 相似文献
55.
56.
57.
Yen‐Yu Chen Yuh‐Ming Chang Kuan‐Yi Wang Pei‐Ni Chen You‐Cheng Hseu Ke‐Min Chen Kun‐Tu Yeh Chih‐Jung Chen Li‐Sung Hsu 《Environmental toxicology》2019,34(3):233-239
Glioblastoma (GBM) is the most mortality brain cancer in the world. Due to high invasion and drug resistance cause the poor prognosis of GBM. Naringenin, an ingredient of citrus, exhibits many cellular functions such as antioxidant, anti‐inflammation, and anticancer. Naringenin inhibits the migration of bladder and lung cancer via modulation of MMP‐2 and/or MMP‐9 activities, Naringenin inhibits migration and trigger apoptosis in gastric cancer cells through downregulation of AKT pathway. However, the effects of naringenin in GBM still remain to be elucidated. In this study, we reveal the molecular mechanisms of naringenin in the inhibition of migration and invasion in GBM. No overt alternation of cell proliferation was found in of GBM 8901 cells treated with different concentration of naringenin. Slight decreased cell viability was found in GBM 8401 cell treated with 200 and 300 μM naringenin. Significant reduction of migration and invasion as assayed by Boyden chamber analysis was found in of GBM cells treated with 100, 200, and 300 μM naringenin. Zymography analysis also revealed that the activities of MMP‐2 and MMP‐9 of GBM cells were significantly inhibited in response to 100, 200, or 300 μM naringenin treatment. Proteins of MMP‐2 and MMP‐9 were downregulated in naringenin treated GBM cells. In addition, naringenin also attenuated the activities of ERK and p38. Naringenin decreased mesenchymal markers (snail and slug) expression as revealed by Western blot analysis. Taken together, our findings indicated that naringenin eliminated the migration and invasion of GBM cells through multiple mechanisms including inhibition of MMPs, ERK, and p38 activities and modulation of EMT markers. Our results also suggested that naringenin may be a potential agent to prevent metastasis of GBM. 相似文献
58.
Yoko Matsuda Hisashi Yoshimura Yuh Fukuda Koji Murai Hiroshi Honma Ryuji Ohashi Zenya Naito Toshiyuki Ishiwata 《Pathology international》2014,64(4):173-177
Aortoesophageal fistula (AEF) is highly lethal. A 74‐year‐old man presented with hematemesis and consciousness loss. He had a long‐term history of hypertension and gout. Computed tomography revealed an aneurysm of the distal descending thoracic aorta, which was treated by insertion of an aortic stent graft. After 24 days of stenting, endoscopic examination revealed an AEF. After 6 months of stenting, he died owing to mediastinitis. On autopsy, macroscopically, we found a 4 × 2.5‐cm, oval, well‐circumscribed AEF. We identified squamous epithelium in the area surrounding the AEF that covered the thoracic aorta inner cavity. Immunohistochemical analysis revealed that the squamous epithelium in the thoracic aorta was positive for p63 and 34βE12. In conclusion, we encountered a long‐term AEF case with aortic squamous metaplasia. To the best of our knowledge, human aortic metaplasia has never been reported. In the present case, aortic squamous metaplasia retained continuity with the esophageal squamous epithelium; therefore, the migration of the squamous epithelium through the AEF may have been induced by aortic erosion. 相似文献
59.
Chao-Hung Kuo Chung-Jung Liu Chien-Yu Lu Huang-Ming Hu Fu-Chen Kuo Yu-Sen Liou Yuan-Chieh Yang Ming-Chia Hsieh Oscar K. Lee Deng-Chyang Wu Sophie S.W. Wang Yao-Li Chen 《International journal of medical sciences》2014,11(1):7-16
Gender differences in terms of mortality among many solid organ malignancies have been proved by epidemiological data. Estrogen has been suspected to cast a protective effect against cancer because of the lower mortality of gastric cancer in females and the benefits of hormone replacement therapy (HRT) in gastric cancer. Hence, it suggests that 17β-estradiol (E2) may affect the behavior of cancer cells. One of the key features of cancer-related mortality is metastasis. Accumulating evidences suggest that human bone marrow mesenchymal stem cells (HBMMSCs) and its secreted CCL-5 have a role in enhancing the metastatic potential of breast cancer cells. However, it is not clear whether E2 would affect HBMMSCs-induced mobility in gastric cancer cells. In this report, we show that CCL-5 secreted by HBMMSCs enhanced mobility in human AGS gastric cancer cells via activation of Src/Cas/Paxillin signaling pathway. Treatment with specific neutralizing antibody of CCL-5 significantly inhibited HBMMSCs-enhanced mobility in human AGS gastric cancer cells. We further observe that 17β-estradiol suppressed HBMMSCs-enhanced mobility by down-regulating CCL5-Src/Cas/paxillin signaling pathway in AGS cells. Collectively, these results suggest that 17β-estradiol treatment significantly inhibits HBMMSCS-induced mobility in human AGS gastric cancer cells. 相似文献
60.
Netrporn Chinvipas Yuh Hasegawa Kazuto Terada 《Odontology / the Society of the Nippon Dental University》2014,102(1):89-97
The aim of this study was to investigate the influences of repeated bonding, using 2 different orthodontic adhesive systems, on the shear bond strength (SBS) and the enamel surface morphology. Sixty premolars were divided into 2 groups (n = 30), and either Transbond XT (T group) or Fuji Ortho LC (F group) adhesives were used. SBS was measured 24 h after bonding, using a universal testing machine. Then, the enamel surfaces were investigated and the mode of failure was described using adhesive remnant index (ARI) scores. After each debonding, 10 teeth from each group were examined by scanning electron microscopy to determine the penetration of adhesives, the length of resin tags, and the state of the enamel surface. The other teeth were subjected to two more bonding/debonding procedures. In T group, the second debonding sequences had significantly higher bond strengths than the other sequences. The length of resin tags was greatest in the second debonding sequence, although there was no significant difference. In F group, the SBS increased with further rebonding and the failure mode tended towards cohesive failure. In both groups, the ARI scores increased with rebonding. Enamel loss could have occurred with both adhesives, although the surfaces appeared unchanged to the naked eye. From this study, we suggest that enamel damage caused by repeated bonding is of concern. To prevent bond failure, we should pay attention to the adhesion method used for bondable retainers. 相似文献