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   301067篇
  免费   8400篇
  国内免费   1144篇
耳鼻咽喉   3169篇
儿科学   8463篇
妇产科学   4884篇
基础医学   36959篇
口腔科学   4658篇
临床医学   24106篇
内科学   53383篇
皮肤病学   4770篇
神经病学   26718篇
特种医学   16000篇
外科学   45121篇
综合类   2844篇
现状与发展   3篇
一般理论   30篇
预防医学   24570篇
眼科学   5918篇
药学   20418篇
中国医学   2117篇
肿瘤学   26480篇
  2023年   935篇
  2022年   2827篇
  2021年   4540篇
  2020年   2190篇
  2019年   3078篇
  2018年   25179篇
  2017年   19986篇
  2016年   22983篇
  2015年   6488篇
  2014年   7416篇
  2013年   8470篇
  2012年   18316篇
  2011年   31560篇
  2010年   24691篇
  2009年   16603篇
  2008年   26754篇
  2007年   28523篇
  2006年   7114篇
  2005年   8242篇
  2004年   8651篇
  2003年   8901篇
  2002年   6425篇
  2001年   3315篇
  2000年   3205篇
  1999年   2313篇
  1998年   1111篇
  1997年   877篇
  1996年   601篇
  1995年   553篇
  1994年   489篇
  1993年   398篇
  1992年   793篇
  1991年   790篇
  1990年   769篇
  1989年   639篇
  1988年   521篇
  1987年   521篇
  1986年   361篇
  1985年   406篇
  1984年   285篇
  1983年   216篇
  1982年   161篇
  1981年   172篇
  1980年   171篇
  1979年   229篇
  1978年   178篇
  1977年   125篇
  1976年   145篇
  1975年   127篇
  1974年   161篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
Persistent uterine prolapse with secondary acute renal failure is a very uncommon event. We report the case of a 77-year-old woman with a 5-year history of uterine prolapse. She was referred to our gynecologic oncology service for 3rd degree uterine prolapse and was found to have bilateral hydronephrosis and acute renal insufficiency. The patient was fitted for a pessary to manage the uterine prolapse, which resulted in resolution of her hydronephrosis and renal insufficiency. Prompt assessment with nephrology consultation and pessary placement for patients with 3rd degree genital prolapse is imperative to ensure that irreversible renal complications do not manifest themselves. This study was supported by a grant from the Women’s Cancer Research Foundation.  相似文献   
995.
INTRODUCTION: Recently, growing clinical evidence has suggested that sexual dysfunction is more prevalent in women with overactive bladder (OAB). Aims. However, there has been no basic research to clarify the relationship between OAB and female sexual dysfunction. Therefore, we investigated this issue using a rabbit model of OAB. METHODS: Twenty-seven New Zealand white female rabbits were randomly divided into the OAB and control groups. MAIN OUTCOME MEASURES: The contractile responses of clitoral cavernous strips to K(+), phenylephrine (PE), Bay K 8644, and endothelin (ET)-1, and the relaxation responses of acetylcholine (ACh), sodium nitroprusside (SNP), and Y-27632 to PE-induced contraction by measuring isometric tension. Results. The contractile responses to K(+), PE, Bay K 8644, and ET-1 were significantly more increased in the OAB group in a dose-dependant manner than in the control group (P < 0.05), and the responses to ET-1 were more prominent than those to the remaining substances (P < 0.01). The increased contractile responses to ET-1 were blocked by BQ123 (ET(A) receptor antagonist) but not by BQ788 (ET(B) receptor antagonist). Clitoral cavernosal strips from the OAB group were more difficult to relax than those from the control group in terms of ACh- and SNP-induced relaxation (P < 0.05). The Y-27632-induced relaxant responses to PE- and ET-1-induced contraction were less prominent in the OAB group than in the control group. CONCLUSIONS; The results of this study provide evidence that female OAB may deteriorate clitoral engorgement, which is associated with a greater force generation by increased calcium sensitization and subsequently decreased of relaxation. The activation of ET and Rho-kinase system may be crucial to negatively effect the clitoral smooth muscle relaxation in experimentally induced OAB animal model. But whether these vasomotor effects are revived in human clitoris is still debatable.  相似文献   
996.
997.
998.
NF-kappaB is known to play a crucial role in the regulation of genes controlling the immune system, apoptosis, tumor cell growth, and tissue differentiation. Bioassay-guided fractionation of the n-hexane-soluble fraction of a methanol extract of Amorpha fruticosa afforded four new compounds, 5, 7, 8, and 9, and eight known compounds. Their structures were elucidated by spectroscopic methods. All compounds inhibited NF-kappaB activity, and tephrosin (1), 11-hydroxytephrosin (2), and deguelin (3) were the most active, with IC50 values of 0.11, 0.19, and 0.22 microM, respectively, in TNF-alpha-stimulated HeLa cell-based reporter gene assays. Further investigations showed that compounds 1, 5, and 6 blocked NF-kappaB/DNA binding activity and suppressed the expression of NF-kappaB target genes.  相似文献   
999.
Phytochemical study on a methanol-soluble extract of the leaves of persimmon (Diospyros kaki) resulted in the isolation of two new ursane-type triterpenoids, 3alpha,19alpha-dihydroxyurs-12,20(30)-dien-24,28-dioic acid (1) and 3alpha,19alpha-dihydroxyurs-12-en-24,28-dioic acid (2), together with 12 known ursane- and oleanane-type triterpenoids (3-14). Triterpenoids with a 3beta-hydroxy group were found to inhibit protein tyrosine phosphatase 1B (PTP1B) activity, with IC50 values ranging from 3.1+/-0.2 to 18.8+/-1.3 microM, whereas those with a 3alpha-hydroxy moiety were not active.  相似文献   
1000.
Interleukin-1 (IL-1), a cytokine produced predominantly by cells from the macrophage lineage, can affect multiple neuroendocrine and metabolic functions. IL-1alpha production by cultured peripheral blood mononuclear cells from an obese group was significantly elevated in comparison to a control group. The aim of this study was to investigate whether the IL-1alpha polymorphism and Sasang constitution, a major branch in Korean traditional medicine, were related to obesity. Genotyping was done in 182 healthy females with a marked variation in body mass index (BMI) by a PCR-restriction fragment length polymorphism assay. The T allele was associated with decreased BMI (p = 0.020). In a subgroup with BMI values ranging from 27 approximately 29 kg/m(2), the frequency of the T allele was significantly decreased (p = 0.004, odds ratio, OR = 0.141 compared to a subgroup with a BMI values less than 25 Kg/m(2)). In addition, in Taeumin female subjects, the frequency of the IL-1alpha T allele was markedly decreased in a subgroup with BMI values in the range of 27 approximately 29 kg/m(2) compared to a lean group with BMI values less than 25 kg/m(2) (p = 0.004, OR = 0.139). In Korean women, an association was found between -889C/T polymorphism in the regulatory region of the IL-1alpha gene and BMI values. In addition, an association was found among IL-1alpha polymorphism, obesity, and the Sasang constitution.  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