首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   87868篇
  免费   8002篇
  国内免费   6590篇
耳鼻咽喉   706篇
儿科学   918篇
妇产科学   1057篇
基础医学   10766篇
口腔科学   1648篇
临床医学   12058篇
内科学   13241篇
皮肤病学   836篇
神经病学   4781篇
特种医学   3207篇
外国民族医学   61篇
外科学   8547篇
综合类   14979篇
现状与发展   30篇
一般理论   3篇
预防医学   5222篇
眼科学   2546篇
药学   9125篇
  68篇
中国医学   4792篇
肿瘤学   7869篇
  2024年   316篇
  2023年   1641篇
  2022年   3843篇
  2021年   4659篇
  2020年   3491篇
  2019年   3044篇
  2018年   3130篇
  2017年   2870篇
  2016年   2611篇
  2015年   4125篇
  2014年   4917篇
  2013年   4183篇
  2012年   6302篇
  2011年   7126篇
  2010年   4272篇
  2009年   3259篇
  2008年   4189篇
  2007年   4508篇
  2006年   4422篇
  2005年   4563篇
  2004年   2786篇
  2003年   2546篇
  2002年   2219篇
  2001年   1910篇
  2000年   2148篇
  1999年   2499篇
  1998年   1666篇
  1997年   1588篇
  1996年   1215篇
  1995年   1057篇
  1994年   887篇
  1993年   606篇
  1992年   720篇
  1991年   614篇
  1990年   554篇
  1989年   481篇
  1988年   392篇
  1987年   350篇
  1986年   247篇
  1985年   190篇
  1984年   92篇
  1983年   76篇
  1982年   41篇
  1981年   45篇
  1980年   29篇
  1979年   30篇
  1965年   1篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Liu H  Zhang T  Li X  Huang J  Wu B  Huang X  Zhou Y  Zhu J  Hou J 《Cancer science》2008,99(11):2185-2192
Fundamental studies have suggested that matrix metalloproteinases-7 (MMP-7) expression is associated with chemoresistance and constitutes a prognostic factor in several solid tumors. The present study assessed the prognostic and predictive value of MMP-7 in tumors of patients with advanced non-small cell lung cancer (NSCLC) treated with platinum-based chemotherapy. In total, 159 patients with stage III and IV NSCLC were retrospectively enrolled. Immunohistochemistry was performed to evaluate the expression of MMP-7, apoptosis-related proteins Bcl-2, Bax, Fas and FasL and the Ki-67 proliferation marker. The TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling) method was performed to investigate tumor apoptosis. Ninety carcinomas (56.6%) were identified as high expression of MMP-7. Overexpression of MMP-7 was more frequent in adenocarcinomas than in squamous cell carcinomas (P = 0.032). The expression of MMP-7 was positively related with Ki-67 index and Bcl-2, but not apoptosis index. MMP-7 status was correlated inversely with response to chemotherapy in overall patients (response rates, 20.0% and 35.8%, for patients with high-MMP-7 and low-MMP-7 tumors, respectively, P = 0.036), especially in adenocarcinoma (P = 0.021), but not in patients with squamous cell carcinomas (P = 0.373). The overall survival was significantly lower in NSCLC patients with high MMP-7 than in those with low MMP-7 (P < 0.001). A Cox regression analyses also demonstrated MMP-7 status to be a significant prognostic factor (hazard ratio, 5.49 P = 0.001). These findings suggest that the expression level of MMP-7 in tumor cells is predictive of response to chemotherapy and outcome in patients with advanced NSCLC receiving platinum-based chemotherapy.  相似文献   
992.
Zhou X  Hu W  Qin X 《The oncologist》2008,13(9):954-966
Rituximab, a genetically engineered chimeric monoclonal antibody specifically binding to CD20, was the first antibody approved by the U.S. Food and Drug Administration for the treatment of cancer. Rituximab significantly improves treatment outcome in relapsed or refractory, low-grade or follicular B-cell non-Hodgkin's lymphoma (NHL). However, there are also some challenges for us to overcome: why approximately 50% of patients are unresponsive to rituximab in spite of the expression of CD20, and why some responsive patients develop resistance to further treatment. Although the antitumor mechanisms of rituximab are not completely understood, several distinct antitumor activities of rituximab have been suspected, including complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), apoptosis, and direct growth arrest. To counteract resistance to rituximab therapy, several strategies have been developed to: (a) augment the CDC effect by increasing CD20 expression, heteroconjugating rituximab to cobra venom factor and C3b, and inhibiting membrane complement regulatory protein, especially CD59, function; (b) enhance the ADCC effect through some immunomodulatory cytokines and CR3-binding beta-glucan; and (c) reduce the apoptotic threshold or induce apoptotic signaling on the tumor. Extensive studies indicate that rituximab combined with these approaches is more effective than a single rituximab approach. Herein, the mechanism of action of and resistance to rituximab therapy in B-cell NHL, in particular, the involvement of the complement system, are extensively reviewed.  相似文献   
993.
994.
995.
Deng R  Li W  Guan Z  Zhou JM  Wang Y  Mei YP  Li MT  Feng GK  Huang W  Liu ZC  Han Y  Zeng YX  Zhu XF 《Oncogene》2006,25(53):7070-7077
It has been shown that acetylcholinesterase (AChE) expression was induced during apoptosis and the anti-sense oligonucleotides and siRNA of AChE may prevent apoptosis in various cell types. However, the mechanisms underlying AChE upregulation remain elusive. We demonstrated here that c-Jun NH2-terminal kinase (JNK) could mediate AChE expression. In this study, both etoposide and excisanin A, two anticancer agents, induced apoptosis in colon cancer cell line SW620 as determined by Annexin V staining, the cleavage of caspase-3 and the proteolytic degradation of poly (ADP-ribose) polymerase (PARP). The results showed that both the agents upregulated AChE in SW620 cells. In the meantime, JNK was also activated and the expression and phosphorylation of c-Jun increased in SW620 cells exposed to the two agents. The induced AChE mRNA and protein expression could be blocked by SP600125, a specific inhibitor of SAPK/JNK, and small interfering RNA directed against JNK1/2. Transfection with adenovirus-mediated dominant negative c-Jun also blocked the upregulation of AChE expression. Together, these results suggest that AChE expression may be mediated by the activation of JNK pathway during apoptosis through a c-Jun-dependent mechanism.  相似文献   
996.
Zhou CH  Wang JY  Cao SY  Shi XH  Zhang YG  Liu M  Wang X  Huang J  Yang YG  Wei D  Yang Z 《癌症》2011,30(10):721-730
In European populations, 7 single nucleotide polymorphisms (SNPs) on chromosome 17q, 3 SNPs on 17q12, and 4 SNPs on 17q24.3 were recently identified to be closely related to the risk of prostate cancer by a genome-wide association study. In Japanese populations, the correlation between 2 SNPs on 17q and the risk of prostate cancer and tumor aggressiveness was also confirmed by a large-scale experiment. However, whether 17q is associated with prostate cancer and its clinical manifestations in Chinese populations is still unknown. Therefore, we conducted a case-control study in a northern Chinese population and tested 2 SNPs, rs4430796 and rs1859962, on 17q in 124 prostate cancer patients and 111 controls using polymerase chain reaction-high resolution melting curve (PCR-HRM) combined with sequencing. We analyzed the association of the 2 SNPs with the risk of prostate cancer as well as patients' lifestyles, onset ages, Gleason scores, PSA levels, and pathologic stages. We found a significant difference in the G allele of SNP rs1859962 (P = 0.035, OR = 1.51, 95% CI = 1.03-2.21) but not in the rs4430796 genotype frequency or allele frequency distribution between prostate cancer patients and the controls (P > 0.05). Neither of the SNPs was significantly associated with the onset age, Gleason score, PSA level, pathologic stage, or other clinical indicators of patients with prostate cancer (P > 0.05). Our results show that polymorphism of the G allele of SNP rs1859962 is associated with the risk of prostate cancer in a Chinese population.  相似文献   
997.
998.
SOFTTISSUESARCOMAS(STS)accountforapproximatelyl%ofadultmalignanciesandl5%ofpediatricmalignancies.Theuseofradicalsurgeryisthem0steffectivemethodfortreatmentofearystageSTS.Unfortunately,manypatientsarediagnosedlate0rreceiveinadequateprimarysurgerysothatmetastasesultimatelyoccULAlthoughsalvagetreatthentbyexcisionofthemetastasesissuccessfulforsomepatients,themajoritywilldiefromprogressivedisease.Doxorubicin(Adriamycin,ADR)isthemostactivesingleagentinsofttissuesarcomas,witharesponserate…  相似文献   
999.
1000.
目的 探讨游离组织瓣移植修复口腔颌面软硬组织缺损的特点及技巧、手术适应证、术中和术后注意事项。方法 应用显微外科技术,以前臂皮瓣、腓骨皮瓣和腹直肌皮瓣游离移植方法对21例口腔颌面部术后软硬组织缺损行一期修复。结果 术后观察2-22个月,组织瓣存活19例,功能良好,外形满意;失败2例。结论 游离组织瓣移植是修复口腔颌面软硬组织缺损的理想方法。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号