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   254790篇
  免费   34614篇
  国内免费   7955篇
耳鼻咽喉   1967篇
儿科学   3084篇
妇产科学   6142篇
基础医学   17790篇
口腔科学   3422篇
临床医学   22422篇
内科学   29556篇
皮肤病学   2192篇
神经病学   3847篇
特种医学   8605篇
外国民族医学   265篇
外科学   33265篇
综合类   31153篇
现状与发展   44篇
一般理论   12篇
预防医学   18846篇
眼科学   945篇
药学   17796篇
  163篇
中国医学   5462篇
肿瘤学   90381篇
  2024年   813篇
  2023年   5617篇
  2022年   10637篇
  2021年   14164篇
  2020年   13130篇
  2019年   11926篇
  2018年   11561篇
  2017年   11790篇
  2016年   12633篇
  2015年   14123篇
  2014年   20789篇
  2013年   21513篇
  2012年   16314篇
  2011年   16659篇
  2010年   12183篇
  2009年   12300篇
  2008年   12582篇
  2007年   11654篇
  2006年   10349篇
  2005年   8564篇
  2004年   7101篇
  2003年   5927篇
  2002年   5036篇
  2001年   4580篇
  2000年   3759篇
  1999年   3171篇
  1998年   2692篇
  1997年   2383篇
  1996年   1934篇
  1995年   1788篇
  1994年   1467篇
  1993年   1185篇
  1992年   1019篇
  1991年   923篇
  1990年   701篇
  1989年   662篇
  1988年   560篇
  1987年   482篇
  1986年   378篇
  1985年   494篇
  1984年   388篇
  1983年   260篇
  1982年   266篇
  1981年   236篇
  1980年   213篇
  1979年   147篇
  1978年   85篇
  1977年   79篇
  1976年   68篇
  1975年   38篇
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
991.
The mortality profile of female nurses and teachers in British Columbia (BC) was examined using age-standardized proportional mortality ratios (PMRs) calculated for the period 1950–1984. Lowered overall mortality among nurses was seen for degenerative heart disease and for cerebrovascular accidents. Significantly elevated PMR values were observed for cancer of the breast and ovary in nurses of age 20–65 years. PMRs were significantly elevated for cancer of the pancreas and leukemia among those age 20 years and older. Elevated values were also observed for motor vehicle accidents and suicide among nurses in both age groups. Lower than expected mortality from degenerative heart disease and cerebrovascular accidents was seen in working age teachers (age 20–65 years). However, elevated PMRs were detected for carcinoma of the colon, breast, endometrium, brain, and melanoma. Among those 20 years and over, significantly elevated PMRs were also observed for cancers of the ovary and other digestive organs. Elevated PMRs were found for motor vehicle and aircraft accidents. Mortality from cirrhosis of the liver was lower than anticipated in both teachers and nurses. A number of significant PMRs declined when deaths of “homemakers” were withdrawn from the comparison group used to generate PMR values, suggesting that risk of death from various causes among women working outside the home differ from those seen in women who are predominantly in the home.  相似文献   
992.
Siblings of a child with cancer   总被引:3,自引:0,他引:3  
Summary A total of 21 healthy siblings were interviewed about their experiences when a brother or sister is diagnosed with cancer. Information about the illness, opinions about who should inform siblings, social support, specific worries and worst memories were studied, as well as perceptions of any differences in the way they were treated by their parents. A short General Impact Scale was developed to assess the extent to which the siblings felt their lives had been disrupted by the illness. Results on these measures were compared with scores on four dimensions of the Sibling Perception Questionnaire (Carpenter & Sahler 1991). Siblings who reported some positive effects as a consequence of the illness (they had become more empathic toward others, or valued life more) perceived their interpersonal relations to be more negatively affected, i.e. there were greater difficulties in their relationships with others especially their parents. Higher scores on communication were related to less of an impact of the illness on life generally. However, these siblings also reported heightened concerns that their brother or sister might die. The data suggested that siblings should have opportunities to talk about implications of the disease, especially worries about death, and more efforts should be made to prepare siblings for visits to hospital and seeing the sick child.  相似文献   
993.
Brain metastases from prostate cancer are rare in postmortem examinations, and even rarer in clinical series. We report an unusual case of brain metastasis from prostate cancer confirmed by antemortem diagnosis in a 72-year-old man. The metastatic brain tumor was surgically resected and the patient was kept stable for more than 19 months after diagnosis of the brain metastasis.  相似文献   
994.
We report a case of advanced gallbladder cancer in a 37-year-old man who presented in June 1993 with malignant obstructive jaundice. After percutaneous transhepatic biliary drainage and several diagnostic imaging examinations, the patient underwent laparotomy under a diagnosis of extremely advanced gallbladder cancer involving the confluence of the hepatic ducts. The tumor, however, was judged to be unresectable because of its massive spread into the liver along Glisson's sheath, and because of histologically proven peritoneal dissemination. After exploratory laparotomy, one course of anticancer chemotherapy (cisplatin, 100 mg/body IV, on day 1, and 5-fluorouracil, 1000 mg/body, on days 1–5, by continuous infusion) was administered and the completely obstructed hepatic duct was dramatically re-canalized. Four courses of chemotherapy were administered over a 16-month period until jaundice recurred. For these 16 months, the patient's quality of life was well maintained without biliary drainage. He died of increased peritoneal dissemination approximately 2 years after the first course of anticancer chemotherapy.  相似文献   
995.
Recurrent wheezing in relation to environmental risk factors in infancy   总被引:2,自引:0,他引:2  
S. Halken    A. Høst    S. Husby    L. G. Hansen    O. Øterballe  J. Nyboe 《Allergy》1991,46(7):507-514
Clinical course and environmental factors were recorded in a prospective study of 276 unselected infants followed from birth to the age of 18 months. The study was performed with a questionnaire at the age of 6 and 12 months and a physical examination at 18 months. Fifty-nine (21%) of the children had greater than or equal to 2 episodes of wheezing before they were 18 months old. A total of 58 (21%) of the children belonged to the lowest social class V, 182 (66%) were daily exposed to passive tobacco smoking at home and/or in daycare, 164 (59%) were breastfed greater than or equal to 3 months, 192 (70%) were in daycare, 62 (22%) lived in flats and 167 (61%) were in daily contact with furred pets at home and/or in daycare. In social class V a preponderance of children were exposed to passive tobacco smoking, a majority were living in flats and a minority were breastfed greater than or equal to 3 months. Linear logistic regression analysis was used for the purpose of assessing the causal effect of environmental risk factors on the risk of recurrent episodes of wheezing before the age of 18 months. The study demonstrated that male sex and daily exposure to passive tobacco smoking were significant risk factors with estimated odds ratios 1.9 and 2.4, respectively. Maternal tobacco smoking seemed to be associated with the highest risk. There was a tendency--though not significant--indicating that breastfeeding greater than or equal to 3 months had a protective effect.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
996.
通过粘度的测量,考察了壳聚糖在不同条件下经不同剂量γ射线辐照所引起的分子量的变化,并分别计算了真空和空气中壳聚糖辐射裂解的G(S)值。  相似文献   
997.
We report herein the case of a 70-year-old man in whom a chest wall implantation of adenocarcinoma of the lung at the drainage tube site was found 4 months after a right lower lobectomy with mediastinal lymph node dissection had been performed for adenocarcinoma of the right lower lobe. The lesion was successfully treated by tumor extirpation. We believe that tumor seeding to the chest wall occurred at the time of thoracotomy. To prevent such tumor seeding, the pleural cavity should be washed out routinely with a massive volume of physiological saline solution prior to closure of the chest wall.  相似文献   
998.
A historical mortality study of a cohort of employees of a gold mining and refining company was carried out in Salsigne, France. A major goal of the study was to investigate the relationship between lung cancer mortality and exposure to arsenic, radon, silica, and other contaminants of the working environment. A twofold excess of lung cancer was found both among miners and smelters, mainly concentrated among workers who had experienced exposure to past levels of arsenic, radon, and silica. The consistency of the results in the mine and the refinery are suggestive of a carcinogenic risk from both soluble and insoluble arsenic, although the potential role of other factors cannot be dismissed. © 1994 Wiley-Liss, Inc.  相似文献   
999.
Multidrug resistance (MDR) is a significant problem in the treatment of cancer. Chemotherapeutic drugs distribute through the cyto- and nucleoplasm of drug-sensitive cells but are excluded from the nucleus in drug-resistant cells, concentrating in cytoplasmic organelles. Weak base chemotherapeutic drugs (e.g., anthracyclines and vinca alkaloids) should concentrate in acidic organelles. This report presents a quantification of the pH for identified compartments of the MCF-7 human breast tumor cell line and demonstrates that (a) the chemotherapeutic Adriamycin concentrates in acidified organelles of drug-resistant but not drug-sensitive cells; (b) the lysosomes and recycling endosomes are not acidified in drug-sensitive cells; (c) the cytosol of drug-sensitive cells is 0.4 pH units more acidic than the cytosol of resistant cells; and (d) disrupting the acidification of the organelles of resistant cells with monensin, bafilomycin A1, or concanamycin A is sufficient to change the Adriamycin distribution to that found in drug-sensitive cells, rendering the cell vulnerable once again to chemotherapy. These results suggest that acidification of organelles is causally related to drug resistance and is consistent with the hypothesis that sequestration of drugs in acidic organelles and subsequent extrusion from the cell through the secretory pathways contribute to chemotherapeutic resistance.  相似文献   
1000.
《Pathology international》1997,47(11):809-811
The Association of Directors of Anatomic and Surgical Pathology have developed recommendations for the surgical pathology reporting of common malignant tumors. The recommendations for carcinoma of the larynx are reported herein.  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