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   6383篇
  免费   318篇
  国内免费   33篇
耳鼻咽喉   62篇
儿科学   116篇
妇产科学   33篇
基础医学   1099篇
口腔科学   295篇
临床医学   335篇
内科学   1502篇
皮肤病学   159篇
神经病学   508篇
特种医学   211篇
外科学   1152篇
综合类   22篇
预防医学   134篇
眼科学   82篇
药学   293篇
中国医学   7篇
肿瘤学   724篇
  2021年   84篇
  2020年   44篇
  2019年   60篇
  2018年   102篇
  2017年   85篇
  2016年   105篇
  2015年   101篇
  2014年   129篇
  2013年   171篇
  2012年   214篇
  2011年   270篇
  2010年   183篇
  2009年   172篇
  2008年   256篇
  2007年   327篇
  2006年   315篇
  2005年   289篇
  2004年   292篇
  2003年   276篇
  2002年   297篇
  2001年   288篇
  2000年   271篇
  1999年   226篇
  1998年   93篇
  1997年   43篇
  1996年   51篇
  1995年   49篇
  1994年   50篇
  1993年   53篇
  1992年   158篇
  1991年   124篇
  1990年   131篇
  1989年   141篇
  1988年   107篇
  1987年   112篇
  1986年   111篇
  1985年   102篇
  1984年   90篇
  1983年   73篇
  1982年   39篇
  1981年   32篇
  1979年   75篇
  1978年   42篇
  1977年   39篇
  1973年   38篇
  1971年   32篇
  1970年   36篇
  1969年   39篇
  1968年   37篇
  1967年   42篇
排序方式: 共有6734条查询结果,搜索用时 31 毫秒
1.
Eosinophilic dermatosis of hematological malignancy is a paraneoplastic skin eruption associated with chronic lymphocytic leukemia and other B‐cell malignancies. It clinically resembles an insect bite reaction and it can precede the symptoms of the hematological malignancy or be related to a more aggressive course. Different treatments have been proposed, but partial response and recurrence are frequent. Herein, we describe a case of eosinophilic dermatosis associated with mantle cell lymphoma with remission after lenalidomide therapy.  相似文献   
2.
OBJECTIVE: It is well documented that cardiopulmonary bypass (CPB) severely impairs cellular immunity. The objective of this study was to investigate the effect of prostaglandin E1 (PGE1) on cellular immunity after CPB. METHODS: Patients who underwent elective cardiac surgery were randomly divided into the PGE1 group (n=12) and the control group (n=12). In the PGE1 group, PGE1 was administered at 20 ng/kg/min from just after the induction of anesthesia to the end of surgery. Peripheral blood mononuclear cells (PBMCs) were taken before anesthesia and on postoperative days 1, 3 and 7 (POD 1, POD 3 and POD 7). Proliferation responses of T cells to phytohemagglutinin (PHA) and pure protein derivative (PPD) antigen were measured as indicators of cellular immunity. RESULTS: PGE1 significantly attenuated the impairment of both PHA and PPD response after cardiac surgery on POD 1 (PHA response, 30 +/- 21% vs. 53 +/- 32%, control vs. PGE, p=0.048; PPD response, 18 +/- 21% vs. 39 +/- 27%, control vs. PGE, p=0.046). The reduced glutathione content of PBMCs in the control group was significantly decreased on POD 1. CONCLUSION: PGE1 attenuated the impairment of cellular immunity after cardiac surgery with CPB by reducing oxidative stress on PBMCs.  相似文献   
3.
4.
Background In cases of synchronous colorectal hepatic metastases, the primary colorectal cancer strongly influences on the metastases. Our treatment policy has been to conduct hepatic resection for the metastases at an interval of 3 months after colorectal resection. We examined the appropriateness of interval hepatic resection for synchronous hepatic metastasis. Materials and methods The subjects were 164 patients who underwent resection of hepatic metastasis of colorectal cancer (synchronous, 70 patients; metachronous, 94 patients). Background factors for hepatic metastasis and postoperative results were compared for synchronous and metachronous cases. Results The cumulative survival rate for 164 patients at 3, 5, and 10 years postoperatively was 71.9%, 51.8%, and 36.6%, and the post-resection recurrence rate in remnant livers was 26.8%. Interval resection for synchronous hepatic metastases was conducted in 49 cases after a mean interval of 131 days. No difference was seen in postoperative outcome between synchronous and metachronous cases. Conclusion The outcome was similarly favorable in cases of synchronous hepatic metastasis and in cases of metachronous metastasis. Delaying resection allows accurate understanding of the number and location of hepatic metastases, and is beneficial in determining candidates for surgery and in selecting surgical procedure.  相似文献   
5.
Humoral hypercalcemia of malignancy (HHM) in neoplastic syndrome has been most commonly reported in squamous cell carcinoma. Gallbladder carcinoma with HHM is uncommon. In this report, we describe a male case of gallbladder carcinoma with marked hypercalcemia and a high level of serum parathyroid hormone-related peptide (PTHrP). An immunohistochemical examination using PTHrP was also positive.  相似文献   
6.
We studied the spatial frequency characteristics in the upper and lower hemiretina using pattern reversal VECPs. The subjects were 56 normal volunteers ranging in age from 14 to 69 years old. The latency of the first major positive component (P100) of VECPs was measured using checker board pattern stimuli under varying conditions of spatial frequency (112', 56', 28', 14', 7'). For the upper hemiretinal stimuli, the P100 peak latency vs spatial frequencies curve reached minimum at 56' approximately 28' and increased at both lower and higher frequencies. For the lower hemiretinal stimuli, this curve shifted towards lower frequencies. The results suggested that the spatial frequency characteristics between the upper and lower hemiretina were different.  相似文献   
7.
The kapurimycins A1, A2 and A3 were revealed to be new antitumor antibiotics with molecular formula of C27H26O9, C26H24O9 and C27H24O9, respectively. The structures of the kapurimycins were determined by NMR spectroscopic analysis. The kapurimycins are new class of polycyclic microbial metabolites having the tetrahydroanthra-gamma-pyrone skeleton and the beta, gamma-unsaturated delta-keto carboxylic acid structure. The individual components of the kapurimycins differ from one another in the side chain at the pyrone ring of the molecule.  相似文献   
8.
Modern surgery for gastric cancer--Japanese perspective.   总被引:1,自引:0,他引:1  
  相似文献   
9.
To achieve prolonged breath-holding, oxygen was administered just before dynamic CT and high resolution lung CT. Oxygen administration has proved to be a supportive means to improve the quality of CT studies.  相似文献   
10.
We previously reported that the Guardian Bio-Threat Alert (BTA) system could detect (detection limit: about 0.1 μg/ml) staphylococcal enterotoxin B (SEB), botulinum toxins (BTX) A and B, and ricin, with no interference by white-powdered materials or colored matrices. In this study, the capability of the BTA system was further assessed. With 10 min of preheating at 60°C, all toxins could be detected, but with preheating at 80°C, BTX A and B and ricin became undetectable. About 20% SEB could be detected after heating at 80°C, but this detection ability was completely removed after heating at 100°C. The effects of chemicals usually used for decontamination, such as sodium hypochlorite, hydrogen peroxide, formaldehyde, and sodium nitrite, on the detectability of SEB, BTX A, or ricin in the BTA system were also tested. The concentrations giving 50% line intensity for SEB, BTX A, and ricin were 3.1, 11, and 15 μM for sodium hypochlorite and 88, 210, and 60 mM for formaldehyde, respectively. The addition of hydrogen peroxide or sodium nitrite did not decrease the detectability even when used at high concentrations.  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