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   61410篇
  免费   5326篇
  国内免费   4064篇
耳鼻咽喉   522篇
儿科学   804篇
妇产科学   1067篇
基础医学   7834篇
口腔科学   969篇
临床医学   7820篇
内科学   9608篇
皮肤病学   705篇
神经病学   3629篇
特种医学   2309篇
外国民族医学   53篇
外科学   6270篇
综合类   8273篇
现状与发展   20篇
一般理论   3篇
预防医学   4131篇
眼科学   1670篇
药学   6420篇
  62篇
中国医学   3053篇
肿瘤学   5578篇
  2024年   178篇
  2023年   940篇
  2022年   2398篇
  2021年   3139篇
  2020年   2285篇
  2019年   2136篇
  2018年   2256篇
  2017年   1893篇
  2016年   1899篇
  2015年   2713篇
  2014年   3372篇
  2013年   2838篇
  2012年   4476篇
  2011年   4948篇
  2010年   2993篇
  2009年   2297篇
  2008年   3171篇
  2007年   3194篇
  2006年   3193篇
  2005年   3161篇
  2004年   2160篇
  2003年   2093篇
  2002年   1816篇
  2001年   1276篇
  2000年   1343篇
  1999年   1435篇
  1998年   940篇
  1997年   898篇
  1996年   686篇
  1995年   628篇
  1994年   517篇
  1993年   333篇
  1992年   424篇
  1991年   373篇
  1990年   331篇
  1989年   286篇
  1988年   295篇
  1987年   241篇
  1986年   234篇
  1985年   184篇
  1984年   127篇
  1983年   98篇
  1982年   54篇
  1981年   52篇
  1980年   40篇
  1979年   97篇
  1978年   41篇
  1975年   40篇
  1974年   52篇
  1973年   30篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
A multicenter phase II trial was conducted to define the activity of letrozole in postmenopausal women with recurrent or advanced endometrial carcinoma, who had no more than one prior line of progestins and never had chemotherapy (except adjuvant). Archival paraffin-embedded tumor samples were retrieved to determine the expression level of estrogen (ER) and progesterone receptor (PgR), p53, HER-2, bcl-2 and PTEN protein, and phosphorylation status of protein kinase B (PKB/Akt). Thirty-two eligible patients were treated with letrozole at 2.5 mg daily continuously, of whom 10 (31%) had prior progestins. Of the 28 patients evaluated for response, one complete and two partial responses were noted; overall response was 9.4% (95% confidence interval 2-25%). Eleven patients had stable disease for a median duration of 6.7 months (range 3.7-19.3 months). Amongst 22 patients who had tumor blocks available, the proportion showing positive expression of the following markers includes: PgR (86%), ER (86%), PTEN (82%), phosphorylated PKB/Akt (59%), bcl-2 (45%), p53 (32%), and HER-2 (0%). None of these markers correlated with response to letrozole or disease progression. In conclusion, letrozole is well tolerated but has little overall activity in this cohort of women with endometrial cancer.  相似文献   
112.
目的:探讨适合睫状体缝合复位术病人的护理方法。方法:对34例(34只眼)因外伤致睫状体分离和脱离导致低眼压,随后行睫状体缝合复位术的病人进行观察和护理。结果:32只眼术后1周至6个月眼压恢复正常,其中5只眼术后2~5个月内分别进行第二次手术或氩离子激光光凝而痊愈。视力改善者21例,无变化者13例。结论:睫状体缝合复位术是治疗外伤性睫状体分离和脱离的有效方法。术前行超声生物显微镜(UBM)检查、术后密切观察眼压变化并给予正确处理、做好心理护理和出院指导是确保手术成功的重要措施。  相似文献   
113.
Q P Ma  Y S Shi  J S Han 《Brain research》1992,583(1-2):292-295
Previous findings from this laboratory with the intracerebral microinjection technique suggested that the periaqueductal gray (PAG), nucleus accumbens, and habenula might constitute a unidirectional loop to play their roles in pain modulation. In the present study we demonstrate that intra-habenular injection of naloxone antagonizes the analgesia elicited by morphine injected into the periaqueductal gray (PAG) and that intra-accumbens injection of naloxone is capable of attenuating the analgesic effects of morphine injected into the habenula. These results indicate that the relationships between these nuclei may be more complex than the putative unidirectional loop.  相似文献   
114.
1988~1991年对内蒙古锡盟地区389例蒙古族新生儿进行了活体观察测量,取得了22项总体发育指标及相应的各项性别指标的均值数据,并以其中体重、身长、顶臀长(坐高)、头围、胸围及上臂围等6项指标与国内外有关资料作了比较和性别间的对比分析,从结果来看,体重高于本地区平均水平110g,高于国内某些城市140~202g;身长及坐高分别矮于本地区平均水平5.13cm及6.54cm,分别矮于国内某些城市4.88~4.89cm及6.60cm。呈圆头型、手足宽短、身躯宽短的粗壮体型。  相似文献   
115.
116.
用参与建立数学模型的521例资料和307例没参与建立数学模型的病例资料验证电子计算机监护慢性肝病的程序。以病理学检查、或以3个月至3年的临床观察结果作为诊断的金标准。254例临床诊断作为对照。验证结果表明(1)计算机监护优于临床诊断,(2)本程序敏感度高。  相似文献   
117.
The portal circulation was reduced to 50% for one hour by partially occluding the superior mesenteric artery, and the relationship between the changes in malondialdehyde (MDA) and multiple organ damage was studied. The results showed that there was a marked change in hepatic enzymology, with MDA values significantly elevated in serum and lung and liver tissues after the reperfusion when compared with controls. These results suggested that lipid peroxidation initiated by free oxygen radicals played an important role in the multiple organ damages, and the extent of organ damage was closely correlated with the contents of MDA in tissues.  相似文献   
118.
Experiments were performed to determine whether bacterial translocation (BT) after hemorrhagic shock is due to a reperfusion injury mediated by xanthine oxidase-derived oxidants. Rats were subjected to 30 minutes of shock (30 mm Hg) followed by reinfusion of shed blood. Twenty-four hours after hemorrhage and reinfusion, the mesenteric lymph node, liver, and spleen were harvested from each animal for bacterial culture, and the ileum and cecum were examined histologically. Sham-shocked (control) rats were instrumented, but blood was not withdrawn. The incidence of BT was higher in the shocked rats (61%) than in the sham-shocked animals (7%) (p less than 0.01). Allopurinol (50 mg/kg, administered orally), a competitive inhibitor of xanthine oxidase, reduced the incidence of shock-induced BT to 14% (p = 0.02). Similarly, rats fed a tungsten-supplemented molybdenum-free diet, which inactivates xanthine oxidase, reduced shock-induced BT to 10% (p = 0.02). The histologic damage cause by hemorrhagic shock was prevented by blocking xanthine oxidase activity. Thus hemorrhagic shock-induced bacterial translocation from the gut appears to be mediated by oxidants generated by activation of the xanthine oxidase system.  相似文献   
119.
Manifestation of EGF receptors and enhancement of an anticancer agent by EGF were studied in cultured cells derived from female genital cancers. 1) The numbers of EGF-receptors of SKG-3a, RMUG-s, HUOA, A-431 and HEC-1 were 1.22 x 10(4), 6.94 x 10(4), 2.75 x 10(4), 5.25 x 10(5) and 0.92 x 10(4) sites per cell respectively. The values for the dissociation constant (Kd) of RMUG-s, SKG-3a, HUOA and HEC-1 were 340pM, 477pM, 989pM and 2,187pM, respectively. 2) All cell lines were stimulated by EGF at low concentrations and inhibited at higher concentrations. The growth stimulation rates for SKG-3a, HEC-1, HUOA and RMUG-s in the presence of 0.01 nM EGF at 48 hours were 8, 18, 21.1 and 3.7%, respectively. The growth inhibition rates for SKG-3a, A-431, HEC-1, HUOA and RMUG-s in the presence of 1.0 nM EGF at 48 hours were 32, 28, 25.8, 11.2 and 6.8%, respectively. 3) The antitumor effect of CDDP was enhanced by the presence of EGF at both a concentration of 0.01 nM (except for A-431) and a concentration of 1.0 nM, in all cell lines. 4) EGF receptors of RMUG-s and HUOA were decreased by CDDP. The values for RMUG-s and HUOA were 1.71 x 10(4), 0.52 x 10(4) (CDDP 0.4 microgram/ml) and 0.95 x 10(4), 0.29 x 10(4) sites per cell (CDDP 2.0 micrograms/ml), respectively. The effect of CDDP on EGF receptors was not recognized in SKG-3a and HEC-1. In brief, EGF receptors were significantly expressed in cell lines derived from female genital cancers.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
120.
Feringa  H.  H.  H.  Van  Waning  V.  H.  Bax  J.  J.  孙凯 《世界核心医学期刊文摘》2006,2(8):59-60
目的:研究心脏药物治疗对外周动脉疾病(PAD)患者远期死亡率的影响。背景:PAD与心血管疾病的患病率和死亡率升高相关。治疗指南推荐积极控制危险因素和改善生活方式。然而PAD患者接受心脏药物治疗的潜在获益尚未明确。方法:在此前瞻性队列研究中,入选2420例连续的PAD(踝臂指数≤  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