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   820篇
  免费   50篇
  国内免费   2篇
耳鼻咽喉   25篇
儿科学   16篇
妇产科学   39篇
基础医学   95篇
口腔科学   33篇
临床医学   34篇
内科学   182篇
皮肤病学   8篇
神经病学   80篇
特种医学   15篇
外科学   150篇
综合类   1篇
一般理论   3篇
预防医学   31篇
眼科学   82篇
药学   19篇
肿瘤学   59篇
  2023年   5篇
  2022年   2篇
  2021年   5篇
  2020年   5篇
  2019年   4篇
  2018年   12篇
  2017年   11篇
  2016年   15篇
  2015年   11篇
  2014年   25篇
  2013年   12篇
  2012年   33篇
  2011年   34篇
  2010年   26篇
  2009年   28篇
  2008年   54篇
  2007年   64篇
  2006年   61篇
  2005年   63篇
  2004年   69篇
  2003年   61篇
  2002年   81篇
  2001年   5篇
  2000年   12篇
  1999年   6篇
  1998年   14篇
  1997年   10篇
  1996年   13篇
  1995年   11篇
  1994年   3篇
  1993年   10篇
  1992年   2篇
  1991年   9篇
  1990年   9篇
  1989年   6篇
  1988年   10篇
  1987年   10篇
  1986年   10篇
  1985年   8篇
  1984年   4篇
  1983年   6篇
  1982年   3篇
  1981年   6篇
  1980年   4篇
  1979年   5篇
  1978年   2篇
  1977年   3篇
  1975年   3篇
  1973年   2篇
  1972年   2篇
排序方式: 共有872条查询结果,搜索用时 207 毫秒
51.
A method for a combined air and isotope ventriculography is described. Twenty-nine infants with suspected hydrocephalus were studied. The merit of the combined study is the possibility of obtaining both anatomical and functional information. A very small amount of radioactivity—15 μc—was found to give satisfactory results. Patterns of cerebrospinal fluid flow in communicating and non-communicating hydrocephalus and in cases of porencephalic cyst and complete obstruction of the lateral ventricles are described.  相似文献   
52.
This study was aimed at investigating the effect of gastrin on the growth of gastric cancer and evaluating postoperative hypergastrinemia in patients that had received various types of gastrectomy for gastric cancer. RT-PCR for gastrin/CCKB receptor mRNA was performed in human gastric cancer cell lines and tissue. The effect of gastrin or glycine-extended gastrin on the growth of gastric cancer cell lines was determined by MTT assay. Serum gastrin levels were compared with respect to the resection type of gastric cancer surgery. Gastrin/CCKB receptor mRNA expression was detected in all 9 gastric cancer cell lines, and in 19 of 29 (62%) gastric cancer tissue samples. Growth of gastric cancer cell lines containing the gastrin/CCKB receptor was significantly enhanced by gastrin and glycine-extended gastrin. The proximal gastrectomy group had a significantly higher mean serum gastrin level than the distal subtotal gastrectomy, total gastrectomy, or preoperative groups (p<0.05). Our study confirms that a high proportion of gastric cancer tissue samples express the gastrin/CCKB receptor, which can stimulate the growth of gastrin/CCKB receptor-positive gastric cancer cells. In addition, we confirm that hypergastrinemia can be induced in about half of patients after proximal gastrectomy. More studies are needed to clarify the relationship between hypergastrinemia and tumor recurrence after proximal gastrectomy.  相似文献   
53.
Germline mutations in DNA mismatch repair (DNA-MMR) genes, mainly hMlh1 and hMsh2, underlie Hereditary Non-Polyposis Colorectal Cancer (HNPCC). Germline hMSH6 gene mutations have been reported in a small subset of HNPCC families. In the present study, ethnically diverse individuals with HNPCC and HNPCC-like features were genotyped for hMsh6 germline mutations using exon-specific PCR, DGGE, and DNA sequencing. The study encompassed 92 individuals representing 88 unrelated families who were previously analyzed for Msh2 and Mlh1 mutations: Jewish Ashkenazim (n = 44), non-Ashkenazim (n = 27), Israeli Moslem-Arab (n = 15), Druze (n=3), and Cypriot non-Jews (n = 3). Of the study population, 71 had colon cancer (CRC), mean age at diagnosis was 50.9±13.2 years (range16–73 years), 5 had endometrial cancer (two with concurrent CRC), (mean 43.6±3.26 years, range 38–45 years), and unaffected individuals (n = 18) were first degree relatives within HNPCC families and were genotyped at a mean age of 48.3±11.7 years (range 30–69 years). Of the 92 individuals analyzed, none showed a truncating hMsh6 mutation, and 6 (6.6%) harbored one of three germline missense mutations: a previously reported one (V878A), and two novel mutations (V509A, S227I). The pathogenic significance of these three missense mutations is yet unclear. In addition, 5 polymorphisms were detected, 2 of which were novel. We conclude that the rate of pathogenic hMsh6 mutations in HNPCC families of Jewish and Mediterranean origin is low, and that mutations in other genes probably account for the phenotype in these families.  相似文献   
54.
The objective was to examine gender differences and similarities in health, function, familial and non-familial social networks; longitudinal resilience in those factors; and their association with risk of mortality in Israeli men and women aged 75-94. We used the Cross-Sectional and Longitudinal Aging Study (CALAS), a stratified random sample of 960 Israeli Jews aged 75-94, drawn on January 1, 1989 from National Population Registry, stratified by gender, age (75-79, 80-84, 85-89, 90-94), and place of birth (Europe/America, Middle East/North Africa, Israel), interviewed twice (Wave 1, 1989-1992; Wave 2, 1993-1995); Wave 1 values and longitudinal resilience predicted the 1999 mortality risk for those alive at both waves. Gender differences and similarities were found at Wave 1 in longitudinal resilience and in risk factors for mortality, partially supporting a gender paradox. Men were more physically active, had better cognition, gave more help to children, relied less on paid caretakers, and attended synagogue more than women, factors associated with better health and functioning. Women had poorer health and functional status and more help from children. More physical activity, synagogue attendance, and resilience in activities of daily living (ADL) were associated with lower risk of mortality for both genders. Women's risk of mortality was reduced by smoking reduction and higher cognitive vitality, and men's by emotional support and solitary leisure activity. Both men and women were resilient, yet there were differences. Gender-neutral mortality reduction programs would include physical activity, religious services, maintenance and improvement of ADL, and engaging in solitary leisure activities; for women, smoking cessation and cognitively challenging activities; and for men, maintaining or increasing emotional ties.  相似文献   
55.
Erythropoietin in heart failure   总被引:3,自引:0,他引:3  
The incidence of both congestive heart failure (CHF) and end-stage renal disease both are increasing. Anemia is common in both conditions and is associated with a marked increase in mortality and morbidity in both CHF and chronic kidney insufficiency (CKI). Each of these 3 conditions can cause or worsen the other 2. In other words, a vicious circle frequently is present in which CHF can cause or worsen both anemia and CKI, in which CKI can cause or worsen both anemia and CHF, and in which anemia can cause or worsen both CHF and CKI. We have called this vicious circle the cardio renal anemia syndrome. Optimal treatment of CHF with all the recommended CHF medications at their recommended doses will, in our experience, frequently fail to improve the CHF and CKI if anemia is present and is not corrected. On the other hand, correction of the anemia with subcutaneous erythropoietin and intravenous iron has caused a great improvement in the CHF including a marked improvement in patient and cardiac function and a marked reduction in the need for hospitalization and for high-dose diuretics. It also frequently has caused renal function to improve or at least stabilize. In addition, patients' quality of life and exercise capacity also have improved with the correction of the anemia. In CKI patients, anemia also may play an important role in increasing the risk for death, coronary heart disease, stroke, and progression to end-stage renal disease. Erythropoietin may have a direct positive effect on the heart and brain unrelated to correction of the anemia by reducing cell apoptosis and by increasing neovascularization, both of which could prevent tissue damage. This could have profound therapeutic implications not only in CHF but in the future treatment of myocardial infarction, coronary heart disease, strokes, and renal failure.  相似文献   
56.
57.
58.
59.
60.
Ovarian follicles obtained from second and third-trimester human fetuses survived 4 weeks in organ culture and secreted 17-beta estradiol (E(2)).  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