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   555871篇
  免费   43046篇
  国内免费   13261篇
耳鼻咽喉   6935篇
儿科学   11236篇
妇产科学   11147篇
基础医学   63420篇
口腔科学   14909篇
临床医学   51186篇
内科学   93256篇
皮肤病学   10738篇
神经病学   30765篇
特种医学   21012篇
外国民族医学   82篇
外科学   76246篇
综合类   60449篇
现状与发展   38篇
一般理论   64篇
预防医学   38540篇
眼科学   11236篇
药学   52369篇
  271篇
中国医学   22041篇
肿瘤学   36238篇
  2023年   2974篇
  2022年   6814篇
  2021年   10048篇
  2020年   8090篇
  2019年   6104篇
  2018年   8196篇
  2017年   8517篇
  2016年   7274篇
  2015年   11182篇
  2014年   14874篇
  2013年   18926篇
  2012年   26471篇
  2011年   27423篇
  2010年   21971篇
  2009年   19969篇
  2008年   24439篇
  2007年   24428篇
  2006年   22434篇
  2005年   18735篇
  2004年   15491篇
  2003年   13868篇
  2002年   12204篇
  2001年   32151篇
  2000年   31619篇
  1999年   24663篇
  1998年   5368篇
  1997年   4442篇
  1996年   4012篇
  1995年   3616篇
  1994年   3260篇
  1993年   2934篇
  1992年   16113篇
  1991年   14880篇
  1990年   14208篇
  1989年   13995篇
  1988年   12598篇
  1987年   12099篇
  1986年   11137篇
  1985年   10348篇
  1984年   6933篇
  1983年   5615篇
  1982年   2729篇
  1979年   5478篇
  1978年   3347篇
  1977年   2972篇
  1975年   2641篇
  1974年   3064篇
  1973年   2865篇
  1972年   2828篇
  1971年   2773篇
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
991.
Y R Zhao  D F Zhang  C Q Pan 《中华内科杂志》1992,31(11):686-8, 730
Viral markers were studied in 79 cases of viral hepatitis with hepatic failure. The results were shown as follows: 8 cases were positive for anti-HAV IgM (10.12%); 76 cases positive for HBsAg or anti-HBc IgM (96.20%) and 41 cases positive for anti-HCV antibodies (51.89%). Among those with anti-HCV positive, 35 cases were co-infected with HBV, 5 cases with HAV and/or HCV, only one was infected with HCV alone 2 cases were HD-Ag positive (2.52%) and one not identified (1.27%). With the reference of clinical findings, patients co-infected with HBV/HCV or anti-HBc IgM positive were more critical and usually entail higher mortality. In cases with HCV co-infections, the positive HBV replication markers seems to be reduced. Hepatic failure without HBV replicative markers had a high rate of hepatic coma as well as poor outcome.  相似文献   
992.
P Icard  Y Chapuis  B Andreassian  A Bernard  C Proye 《Surgery》1992,112(6):972-9; discussion 979-80
BACKGROUND. Because of the rarity of adrenocortical carcinoma, survival rates and prognosis for patients who have undergone operation are not well known. The purpose of the French Association of Endocrine Surgery was to evaluate these factors in all patients treated during a 12-year period by its members. METHODS. One hundred fifty-six patients (95 women, 61 men) with a mean age of 47 years were included. Functional symptoms were found in 52% of patients, and hormonal studies revealed secreting tumors in 62% of cases. Ninety-four percent of the patients underwent resection of the adrenal tumor, and 20% of them had extensive resection because of invasive cancers. Complete resection was achieved in 127 patients (81%) and incomplete resection in 29 patients. Mean tumor weight was 714 gm (range, 12 to 4750 gm), and the mean diameter was 12 cm (range, 3 to 30 cm). The results of the tumor staging were stage I, eight patients (5%); stage II (local disease), 75 patients (48%); stage III (locoregional disease), 39 patients (25%); and stage IV (metastases), 34 patients (22%). RESULTS. The 5-year actuarial survival rates were 34% overall, 42% in curative group, 53% in local cancer group, 24% in regional disease group, and 27% in the reoperated group. One-year actuarial survival rate of the palliative group was 9% (median survival, 6 months). Multivariate analysis showed that better prognosis occurred in patients younger than 35 years of age (p = 0.01) and in patients with androgen-secreting tumors, precursor-secreting tumors, or nonsecreting tumors (p = 0.003). Mitotane improved the survival rate only in patients with metastases who received it after operation (vs non-mitotane-treated patients [p < 0.05]). CONCLUSIONS. In this study age, extent of disease, aspect of the surgical resection, and type of hormonal secretion influenced survival.  相似文献   
993.
Study Objective . To determine the efficacy of high-dose ascorbate supplementation in lowering lipoprotein(a) [Lp(a)] levels in patients with premature coronary heart disease (CHD). Design . Randomized, double-blind, placebo-controlled trial. Setting . Outpatient clinic. Patients . Forty-four patients with documented premature CHD. defined as confirmed myocardial infarction and/or angiographically determined stenosis of 50% or greater in at least one major coronary artery before age 60 years. Interventions . Patients were block randomized on the basis of age, gender, and screening Lp(a) concentrations to receive ascorbate 4.5 g/day or placebo for 12 weeks. Measurements and Main Results . High-dose ascorbate was well tolerated and produced a marked elevation in mean plasma ascorbate levels (+1.2 mg/dl; p<0.001). Multiple linear regression analysis revealed no significant effect of supplementation on postintervention Lp(a) levels (p=0.39) in a model that included treatment group assignment, and baseline Lp(a) levels. Conclusions . Our findings do not support a clinically important lowering effect of high-dose ascorbate on plasma Lp(a) in patients with premature CHD.  相似文献   
994.
995.
We have developed an immunoadsorbent (IA) for ex vivo removal of IgE after in vitro screening of matrix (Sepharose and tresyl-activated Toyopearl) and ligand (monospecific rabbit polyclonal anti-IgE antiserum and monoclonal antibodies (Abs) or their Fab fragments). Specific adsorptive capacity (SAC) for IgE was maximal in Sepharose-based IA with both types of Abs. Fab-containing IA on Sepharose retained 70-90% of the SAC of native Ab-containing IA. Toyopearl-based IA showed comparable SAC under static conditions but worked unsatisfactorily under continuous flow conditions. To assess the complement-activating capacity (CAC) of IA in vitro anaphylatoxin (C3a, C4a, C5a) generation was applied. CAC was directly related with the amount of immobilized Ab ligand, without depending on Ab specific activity. Fab-containing IA showed more CAC than native Ab-containing IA, and polyclonal IA more than monoclonal IA. Therefore, IA for IgE apheresis were prepared from native monoclonal Abs and CNBr-activated Sepharose CL 4B under aseptic conditions and packed into a glass column. This IA was used in 17 clinical IgE apheresis treatments of five atopic asthma patients. No substantial side effects were observed; in vivo IA effectively removed IgE from plasma (83 to 98%).  相似文献   
996.
贺晓生  易声禹 《医学争鸣》1998,19(2):199-201
目的:探讨头颅瞬间旋转后脑干水肿的形成及超微形态学基础。  相似文献   
997.
A 34-year-old woman was admitted with an abnormal shadow on a chest X-ray film. Under a preoperative diagnosis of benign bronchogenic cyst, operation was carried out and the tumor was found to be originating from the right main vagal nerve in the mid-superior mediastinum. The vagal nerve was transected to remove the tumor. Pathological diagnosis was a neurinoma. Postoperative complication was chylothorax which was successfully treated with thoracic drainage and intravenous hyperalimentation.  相似文献   
998.
Serum level of sex hormone-binding globulin (SHBG) was measured by immunoradiometric assay in fifty two breast cancer patients and twenty nine healthy female volunteers. The results are as follows: 1) Although the serum SHBG concentration showed no significant difference between the breast cancer group and the healthy control group, the serum SHBG concentration in postmenopause was significantly higher in the breast cancer group (63.8 +/- 31.2nmol/ml/ml; mean +/- S.D.) than in the healthy control group (40.1 +/- 15.4nmol/ml). 2) Subsequently in the postmenopausal breast cancer group, the serum SHBG concentration was significantly higher in the estrogen receptor (ER)-negative cancer group (97.8 +/- 12.7nmol/ml) than in the ER-positive cancer group (55.8 +/- 32.1nol/ml). 3) No significant relationships were showed between the serum SHBG concentration and obesity or serum estradiol concentration in postmenopausal patients. 4) The serum SHBG concentration showed significant decrease 3 months after radical operation for breast cancer in postmenopausal patients. These results suggest the possibility of the SHBG synthesis in breast cancer tissue.  相似文献   
999.
We studied subsets and cytotoxicity of recombinant interleukin-2 (rIL-2) expanded tumor infiltrating lymphocytes (TIL) from renal cell cancer (RCC) patients. TIL were successfully expanded in 13 of 14 RCC cases using anti-CD3 during initial 48 hours of culture. Percentages of CD8 positive cells among rIL-2 expanded TIL at 1 tp 4 week(s) of culture were 56.2 +/- 15.1% (range 26.2 to 79.8%, N = 13) and not necessarily predominant over CD4 positive cells. NK and LAK activities of TIL at 3 to 6 weeks of culture were 31.6 +/- 15.8% (range 1.4 to 57.4%, N = 9) and 16.6 +/- 11.6% (range 3.8 to 35.6%, N = 6), respectively. Autologous and allogeneic RCC cytotoxicity of TIL at 3 to 4 weeks of culture were 17.9 +/- 19.7% (range 0 to 47.6%, N = 4) and 18.9 +/- 14.8% (range 0 to 47.3%, N = 12), respectively. Since there was no statistical difference between them, autologous specific cytotoxicity was not demonstrated. From these results of present study, it is unlikely that most of effector cells of rIL-2 expanded TIL in autologous RCC lysis are major histocompatibility complex restricted cytotoxic T cells. And we concluded that it is doubtful that TIL is significantly superior over LAK cells in immunotherapy of human RCC.  相似文献   
1000.
Transrectal ultrasonotomography is useful in following patients with benign prostatic hypertrophy, because prostatic shape and weight are precisely assumed. We studied the effect of chlormadinone acetate (CMA) on benign prostatic hypertrophy. CMA (50 mg/day) was administered to 30 patients with benign prostatic hypertrophy. Weight reduction over 10% of the gland was noticed in 24 cases (80%). Mictional conditions were improved in 70% subjectively and in 71.4% objectively. However, the number of nocturia decreased in only 18.9%. Reduction rate of the weight was unrelated with the weight of prostate before administration of CMA. Duration of administration of CMA and the reduction rate were estimated. There was no definite difference in reduction rate for the first 15 months, but there was a slightly high reduction rate after administration of CMA for more than 24 months. In 3 cases, the shape and weight of prostate were studied after discontinuation of CMA. The size of prostate showed a tendency to increase gradually.  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