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   714111篇
  免费   50814篇
  国内免费   1302篇
耳鼻咽喉   9283篇
儿科学   23571篇
妇产科学   17743篇
基础医学   111720篇
口腔科学   20105篇
临床医学   65034篇
内科学   135665篇
皮肤病学   16304篇
神经病学   50604篇
特种医学   26150篇
外国民族医学   76篇
外科学   105595篇
综合类   14974篇
现状与发展   2篇
一般理论   165篇
预防医学   52272篇
眼科学   16532篇
药学   54668篇
  5篇
中国医学   2360篇
肿瘤学   43399篇
  2019年   5572篇
  2018年   8003篇
  2017年   6225篇
  2016年   6944篇
  2015年   7705篇
  2014年   10434篇
  2013年   15738篇
  2012年   20923篇
  2011年   21940篇
  2010年   12988篇
  2009年   12174篇
  2008年   20399篇
  2007年   21959篇
  2006年   22390篇
  2005年   20874篇
  2004年   20422篇
  2003年   19352篇
  2002年   18813篇
  2001年   36645篇
  2000年   37195篇
  1999年   30640篇
  1998年   7979篇
  1997年   6770篇
  1996年   7069篇
  1995年   6692篇
  1994年   6186篇
  1993年   5673篇
  1992年   23181篇
  1991年   23144篇
  1990年   22527篇
  1989年   22280篇
  1988年   20260篇
  1987年   19604篇
  1986年   18671篇
  1985年   17508篇
  1984年   12828篇
  1983年   10880篇
  1982年   6014篇
  1979年   11629篇
  1978年   8228篇
  1977年   6910篇
  1976年   6676篇
  1975年   7343篇
  1974年   8573篇
  1973年   8220篇
  1972年   7746篇
  1971年   7186篇
  1970年   6947篇
  1969年   6371篇
  1968年   5834篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The article is concerned with a study of the mortality rates among the workers engaged at a tire-producing plant, for the 1950-1979 period. In comparison with the control population group, the contributors revealed increased mortality rates caused by cardiovascular diseases, malignant neoplasms, accidents, intoxications and traumas. Analysis of the labour conditions proved the influence of the unfavourable occupational factors on the mortality rates and mortality causes, excepting the indices of mortality caused by accidents, intoxications and traumas.  相似文献   
992.
993.
A 13-year-old girl who had severe brain damage due to unknown prenatal cause presented rhabdomyolysis triggered by a mild viral infection. Her muscle biopsy revealed mild variation in fiber size and type 2 fiber atrophy without excess lipid storage. Biochemical analysis of the biopsied material showed decreased carnitine palmitoyltransferase (CPT) activity (15% of the control). Serum and urinary carnitine levels were normal. Skeletal muscle CT scanning showed multiple low density spots. The patient was diagnosed as having CPT deficiency. She recovered from rhabdomyolysis without renal failure after a month with conservative therapy. CPT deficiency is usually found in young healthy persons. This is the first case report of CPT deficiency which presented severe psychomotor retardation since neonatal period.  相似文献   
994.
995.
996.
N Sato 《Nihon Geka Gakkai zasshi》1986,87(12):1511-1525
The relationship between nutritional status and muscle strength was examined in 73 patients with gastrointestinal carcinoma preoperatively. Nutritional status was assessed by measuring various nutritional parameters. Muscle strength was determined by measurements of %grip strength and respiratory muscle strength expressed as %maximal expiratory and inspiratory pressure (%MEP and %MIP). The results were as follows: %GS was significantly low in the patients who showed low values in body weight (%ideal body weight: %IBW), mid-arm muscle circumference (%AMC), serum albumin (Alb), serum prealbumin (PA), total peripheral lymphocyte count (TLC), and/or nutritional surgical risk index (NRI). %MEP was significantly low in the patients who showed low values in %IBW, %AMC, triceps skin fold, Alb, PA, retinol binding protein, NRI, and/or nutritional assessment index (NAI). %MIP was significantly low in the patients who showed low values in %IBW, %AMC, creatinine height index, Alb, PA, NRI, and/or NAI. %MEP and %MIP were significantly correlated with %GS. Preoperative %GS value was significantly low in the esophageal cancer patients with postoperative pulmonary complications. It was suggested that %GS was a simple and useful nutritional parameter for detecting depletion of the muscle mass and visceral proteins, for respiratory muscle strength, and for functional capacity of muscle.  相似文献   
997.
998.
Human TNF was detected fairly recently and at present the anti-tumor activity of human recombinant TNF is being examined against various malignant tumors of human origin. In the present study, we report the anti-tumor activity of recombinant human TNF against human malignant glioma cell lines in vitro and in vivo, in addition to its combined effects with HuIFN-beta. The in vitro study was conducted as follows. Thirteen human glioma cell lines were exposed to 100 U/ml TNF, 1,000 IU/ml HuIFN-beta, or both, and the suppression rate was calculated on days 3, 5 and 7. In the in vivo study, nude mice carrying a human glioma cell line, KMS II, in the subcutaneous tissues were divided into groups and drugs were administered intratumorally as described below. 1) control, 2) TNF 5,000 U single administration, 3) TNF 5,000 U, intermittently administered (once/week for two weeks), 4) TNF 5,000 U, continuously administered (3/week for two weeks), 5) HuIFN-beta 50 X 10(4) IU (3/week for two weeks), and 6) combination of 4) with 5). Results of the in vitro study revealed some suppressive effects on proliferation of tumor cells on day 7 in all 13 glioma cell lines examined with 100 U/ml TNF. And also, especially in 8 of 13 cell lines, the suppression rate was more than 30%. The suppressive effects of TNF were augmented by combined use of HuIFN-beta in all cell lines, giving a range of suppression of 67.8 to 99.3%. The in vivo study revealed that the mean tumor weight ratios (control = 100%) on day 19 (the end of the experiment) were as follows; single administration of TNF: 41.3%, intermittent: 46.7%, continuous: 26.7%, HuIFN-beta: 65.9%, combination: 18.5%. Statistical analysis disclosed significant suppressive effects on tumor proliferation between the control group and 3 TNF-administered groups (single, intermittent, and continuous) and that suppression in the continuously administered group was more severe in comparison with the group given single administration. Moreover, it was suggested that combination therapy with TNF and Hu IFN-beta was more effective than a single therapy with TNF only or HuIFN-beta only. From the results described above, it was found that human recombinant TNF had some cytotoxic effects against human malignant gliomas in vitro and in vivo, although the degree of cytotoxicity was not always higher in comparison with the effects of TNF.  相似文献   
999.
A randomized clinical trial was performed to compare the efficacy of bilateral oophorectomy with that of tamoxifen at a dose of 10 mg twice daily in premenopausal women with metastatic breast cancer, and to examine the efficacy of each as a crossover treatment. Initial treatment responses were seen in ten of 27 patients (37%) treated with oophorectomy and seven of 26 patients (27%) treated with tamoxifen. The difference was not statistically significant. Crossover responses were seen in five of 15 patients (33%) treated with oophorectomy, including three responses in ten prior tamoxifen nonresponders; and two of 18 patients (11%) treated with tamoxifen. Time to progression distributions were not significantly different during initial treatment, and no significant differences in survival were noted. Thus, there was no overall disadvantage to the use of tamoxifen as opposed to oophorectomy as initial hormonal therapy, and a failure to respond to tamoxifen did not preclude a response to subsequent oophorectomy. Exploratory data analysis within subsets indicated consistent differential treatment effects in the visceral dominant patients. Of the 16 such patients treated with oophorectomy, eight (50%) experienced objective responses but there were no responses in the 14 patients treated with tamoxifen. In the nine visceral dominant crossover patients who had not responded to initial tamoxifen, three (33%) subsequently responded to oophorectomy. Time to progression distributions within the visceral dominant subset appeared to be better for the patients treated initially with oophorectomy. However, one must be very cautious in drawing conclusions from exploratory subset analyses, especially with the small sample size. Further studies would be required to test any hypothesis of differential organ site responsiveness.  相似文献   
1000.
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