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   3594篇
  免费   374篇
  国内免费   32篇
耳鼻咽喉   10篇
儿科学   129篇
妇产科学   152篇
基础医学   450篇
口腔科学   57篇
临床医学   418篇
内科学   788篇
皮肤病学   17篇
神经病学   329篇
特种医学   230篇
外科学   443篇
综合类   95篇
预防医学   348篇
眼科学   57篇
药学   254篇
中国医学   19篇
肿瘤学   204篇
  2023年   29篇
  2022年   29篇
  2021年   81篇
  2020年   56篇
  2019年   81篇
  2018年   91篇
  2017年   71篇
  2016年   88篇
  2015年   112篇
  2014年   133篇
  2013年   166篇
  2012年   213篇
  2011年   230篇
  2010年   145篇
  2009年   141篇
  2008年   169篇
  2007年   170篇
  2006年   173篇
  2005年   182篇
  2004年   145篇
  2003年   140篇
  2002年   126篇
  2001年   60篇
  2000年   59篇
  1999年   69篇
  1998年   48篇
  1997年   47篇
  1996年   55篇
  1995年   38篇
  1994年   34篇
  1993年   43篇
  1992年   51篇
  1991年   46篇
  1990年   49篇
  1989年   60篇
  1988年   48篇
  1987年   50篇
  1986年   48篇
  1985年   48篇
  1984年   42篇
  1983年   26篇
  1982年   20篇
  1981年   23篇
  1980年   28篇
  1979年   26篇
  1978年   32篇
  1977年   15篇
  1975年   15篇
  1974年   19篇
  1971年   15篇
排序方式: 共有4000条查询结果,搜索用时 333 毫秒
1.
2.
3.
Exposure to cadmium via the diet is known to depend to a large extent on the intake of cereal grains, particularly the high-fibre fractions of wheat. Subjects with low iron status absorb more cadmium than those with better iron status. The purpose of the present study was to determine to what extent cadmium accumulation in human placenta is affected by the intake of grain fibre and maternal iron status during pregnancy. Thirty-nine pregnant women participated in the study. In each trimester the women were requested to complete a dietary history and to allow blood samples to be taken for haemoglobin, serum ferritin and serum thiocyanate determinations, the latter as a marker for smoking. At delivery the whole placenta was taken for the determination of the cadmium concentration. The 32 women who had serum thiocyanate levels less than 70 mumol/l, who had completed at least one dietary history and from whom a blood sample was obtained in the third trimester, were included in the final statistical analyses. In the group of women who consumed less than the median intake of grain fibre and had more than 15 micrograms ferritin/l serum in the third trimester, the placenta cadmium concentration was nearly half that in the placentae of women who had consumed more grain fibre or had lower iron status in late pregnancy.  相似文献   
4.
Sonoelasticity imaging of prostate cancer: in vitro results   总被引:2,自引:0,他引:2  
  相似文献   
5.
Evaluation of alcoholism treatment effectiveness needs to be based on the healthy goals that alcoholics themselves identify as important. This research uses ethnography and grounded-theory methods to develop a model of recovering alcoholics' goal progression. The author spent 28 days in a treatment center, engaging in all patient activities, and observed and interviewed 42 participants to determine what they wanted from treatment. The research indicates that recovering alcoholics' goals develop through four stages. Certain kinds of behavior must be accomplished for an alcoholic to move from one stage to another. Behavior that facilitates and inhibits goal progression is identified.  相似文献   
6.
The clinical and ultrasonographic (US) features of 15 cases of mesenteric or omental cyst are herein described. This series included seven male and eight female patients, whose age ranged from 2–89 years. Correct clinical diagnosis was made in two children only, but preoperative US examination accurately demonstrated the lesion in 11 of 13 patients (85%). These cystic lesions usually had a thin wall, internal septations, and fluid content with sedimentation. Enteric duplication cysts had a relatively thick wall merging with the muscle layer of bowel loop, and multiloculation was noted mainly with cystic lymphangiomas or pseudocysts. The diagnostic and surgical management of these lesions are briefly reviewed and their US appearance is illustrated.  相似文献   
7.
8.
Aim: To examine the survival benefit of liver and lung resection for colorectal metastasis and the potential prognostic factors that affect patient survival. Methods: All patients who had resection of lung or liver metastasis for colorectal metastasis in Queen Elizabeth Hospital, Hong Kong from 1995 to 2004 were retrospectively reviewed. The overall and disease‐free survival was analysed, in particularly between liver and lung metastasis. All factors that may have affected the survival were entered into Cox's proportional hazards regression model to identify significant variables associated with survival. Results: At 5 years, the overall survival of patients who had resection of lung and liver metastasis was 44% and 38%, respectively; the disease‐free survival was 26% and 24%, respectively. Overall and disease‐free survival of patients with resection of lung metastasis was comparable to those with resection of liver metastasis. The differentiations of primary tumour and time to metastasis were shown to be significant prognostic factors influencing overall survival. Those patients with systemic chemotherapy after resection of colorectal metastasis demonstrated a significantly higher probability of overall survival. Conclusion: Resection of lung and liver metastases from colorectal origin was safe and both procedures improved survival. The use of chemotherapy after resection of metastasis significantly improved the overall survival.  相似文献   
9.
Ultra wide field fundus biomicroscopy with the Volk Quadraspheric lens   总被引:1,自引:0,他引:1  
Fundus biomicroscopy as a clinical technique has been enhanced significantly by the addition of indirect view condensing lenses. The combination of this type of lens with a corneal contact element allows higher power and better stability so that a wider field can be obtained. The Panfunduscope of Schlegel and the Mainster retinal lens are examples of this design that have been successfully applied to both examination and to pan-retinal photocoagulation. Volk has recently introduced a new aspheric design indirect contact lens system which is higher in power and provides a wider field of view (125 degrees) than previously obtainable. This article describes the optical properties and use of the Quadraspheric lens.  相似文献   
10.
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