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   87273篇
  免费   8603篇
  国内免费   165篇
耳鼻咽喉   1206篇
儿科学   2653篇
妇产科学   1909篇
基础医学   12359篇
口腔科学   2030篇
临床医学   11163篇
内科学   15327篇
皮肤病学   1353篇
神经病学   7277篇
特种医学   2826篇
外国民族医学   10篇
外科学   11811篇
综合类   1734篇
一般理论   72篇
预防医学   10019篇
眼科学   1983篇
药学   6965篇
  1篇
中国医学   81篇
肿瘤学   5262篇
  2021年   1243篇
  2020年   803篇
  2019年   1238篇
  2018年   1525篇
  2017年   1094篇
  2016年   1190篇
  2015年   1338篇
  2014年   1777篇
  2013年   2820篇
  2012年   3812篇
  2011年   4101篇
  2010年   2189篇
  2009年   2083篇
  2008年   3560篇
  2007年   3864篇
  2006年   3680篇
  2005年   3797篇
  2004年   3571篇
  2003年   3283篇
  2002年   3208篇
  2001年   2743篇
  2000年   2840篇
  1999年   2542篇
  1998年   1107篇
  1997年   916篇
  1996年   893篇
  1995年   803篇
  1994年   825篇
  1993年   764篇
  1992年   2110篇
  1991年   2039篇
  1990年   1909篇
  1989年   1875篇
  1988年   1777篇
  1987年   1786篇
  1986年   1690篇
  1985年   1669篇
  1984年   1403篇
  1983年   1269篇
  1982年   850篇
  1981年   734篇
  1980年   652篇
  1979年   1220篇
  1978年   885篇
  1977年   774篇
  1976年   722篇
  1975年   718篇
  1974年   869篇
  1973年   758篇
  1972年   743篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
From 1970 to 1980, 153 patients with stages A2, B1 and B2 prostatic cancer and proved negative pelvic lymph nodes underwent radical prostatectomy (84 underwent radical perineal and 69 underwent radical retropubic prostatectomy). Seventeen patients were lost to followup. Of 136 patients who were followed for 5 years or until death 128 (94 per cent) were alive at 5 years, including 118 (87 per cent) who were without evidence of recurrence. Patients with microscopic invasion of the prostatic capsule have a better outcome at 5 years than those with microscopic involvement of the seminal vesicles. Only 46 of the patients could be assessed at 10 years or had died 6 to 10 years postoperatively. Results at 10 years are considered preliminary, since many more patients will reach the 10-year milestone within the next few years.  相似文献   
82.
Hollingworth described chewing gum as ‘a technique of relaxation’. Recent research has examined this issue and there is evidence that chewing gum can prevent the adverse effects of acute stress. There are also plausible biological mechanisms that could explain such effects. It is now important to examine chewing gum and chronic stress and the present study involved a survey of this topic. The survey covered the ‘stress process’, collecting data on exposure to stressful events, levels of perceived stress and health outcomes. Frequency of chewing gum was also recorded. Potential confounding factors (demographics, personality and health-related behaviours) were also recorded. The web-based survey was completed by a community sample of 2,248 full-time workers (68% female. Mean age: 35 years, range 18–74 years). Sixty-one per cent of the sample were gum chewers. The results showed that chewing gum was associated with lower levels of perceived stress (both at work and life in general). Gum chewers were also less likely to be depressed and to have seen their doctor for high blood pressure or high cholesterol. Chewing gum was associated with lower levels of alcohol consumption and with cigarette smoking. Gum chewers were also more likely to be neurotic extraverts. Those who chewed gum were also more likely to be exposed to negative factors at work. Logistic regression analyses showed that the effects of chewing gum on stress and health remained significant when these confounding factors were controlled for. These results suggest that chewing gum may be a simple way of preventing stress and the negative health outcomes that are often associated with it. Intervention studies are now required and the mechanisms underlying the effects reported here need further investigation. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
83.
Cholangiocarcinomas (CC) frequently demonstrate lymphatic spread. We investigated lymph node (LN) counts after resection of extrahepatic CC and survival based on the SEER 1973–2004 database. Out of 20,068 CC patients, 1,518 individuals were selected based on M0 stage and at least one LN examined. Primary cancer sites included gallbladder (29%), extrahepatic bile ducts (26%), and intrapancreatic/ampullary bile ducts (45%); 42% of patients were LN-positive. The median number of LNs examined was four (range 1–39). Median survival was 37 months for LN-negative and 16 months for LN-positive cancers. Multivariate prognostic variables were the number of positive LNs, primary site, age (all at p < 0.0001), gender (p = 0.002), size (p = 0.005), T category (p = 0.009), and total LN count (or number of negative LNs obtained, p = 0.01). The impact of total LN counts was seen in LN-negative (median survival, 1 vs 10 or more LNs examined: 27 vs 51 months, p = 0.002) and LN-positive disease (10 vs 22 months, p < 0.0001). Survival prediction of extrahepatic CCs is strongly influenced by total LN counts and numbers of negative LNs obtained. Although the resulting incremental benefit is small, dissection and examination of 10 or more LNs should be considered for curative intent resections.  相似文献   
84.
85.
86.
87.
88.
89.
Objective Approximately 10% of patients with neurofibromatosis I (NFI) patients will have central nervous system (CNS) tumors. The most common of these are hypothalamic–optic gliomas, followed by brainstem and cerebellar pilocytic astrocytomas. While isolated pilocytic astrocytomas in NFI are well described, the appearance of multiple pilocytic astrocytomas in an individual patient is less common. The most frequent combination in NFI patients with more than one pilocytic astrocytoma is optic tract/hypothalamic and brainstem. Other combinations are exceedingly rare; multiple pilocytic astrocytomas have only been reported once in the cerebral hemispheres in a patient with NFI. This report presents the first documented case, to our knowledge, of multiple pilocytic astrocytomas in the cerebellum of a patient with NF1. Methods Case report. Conclusion The finding of multiple cerebellar pilocytic astrocytomas in a patient with NF1 is important because it expands the spectrum of presentations for patients with NF1 and also highlights specific diagnostic and therapeutic challenges faced by the treating physicians. The genetic and molecular basis of NF1 is reviewed. Strategies of diagnosis and treatment outlined here are relevant to both patients with NF1 and all patients with multiple posterior fossa tumors.  相似文献   
90.
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