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   68279篇
  免费   3974篇
  国内免费   178篇
耳鼻咽喉   892篇
儿科学   1546篇
妇产科学   1369篇
基础医学   9035篇
口腔科学   2628篇
临床医学   5264篇
内科学   17179篇
皮肤病学   1765篇
神经病学   5961篇
特种医学   1740篇
外科学   9205篇
综合类   313篇
一般理论   26篇
预防医学   5861篇
眼科学   1263篇
药学   4463篇
中国医学   253篇
肿瘤学   3668篇
  2024年   47篇
  2023年   454篇
  2022年   206篇
  2021年   1116篇
  2020年   658篇
  2019年   1186篇
  2018年   2079篇
  2017年   1252篇
  2016年   1337篇
  2015年   2050篇
  2014年   2084篇
  2013年   3058篇
  2012年   5899篇
  2011年   5756篇
  2010年   2667篇
  2009年   1993篇
  2008年   4899篇
  2007年   5082篇
  2006年   5276篇
  2005年   4979篇
  2004年   4470篇
  2003年   4016篇
  2002年   3900篇
  2001年   1583篇
  2000年   2088篇
  1999年   1015篇
  1998年   292篇
  1997年   220篇
  1996年   231篇
  1995年   191篇
  1994年   171篇
  1993年   157篇
  1992年   134篇
  1991年   125篇
  1990年   93篇
  1989年   117篇
  1988年   96篇
  1987年   83篇
  1986年   92篇
  1985年   99篇
  1984年   115篇
  1983年   71篇
  1982年   97篇
  1981年   86篇
  1980年   86篇
  1979年   60篇
  1978年   52篇
  1977年   53篇
  1976年   50篇
  1973年   41篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The aim of this study was to assess alcoholic inpatients' smoking and coffee intake variation following withdrawal. Only moderate smokers (less than 30 cigarettes/day) showed a significant increase of cigarette consumption after alcohol withdrawal. However, their urinary cotinine level did not vary, suggesting a behavioral, and not biological, compensation through smoking following alcohol withdrawal. Heavy smokers (30 cigarettes/day or more) showed no significant clinical or biological variation of smoking behavior. Coffee consumption increased after alcohol withdrawal in all patients, irrespective of smoking habits.  相似文献   
72.
For the treatment of intraabdominal infection, single-agent antimicrobial regimens such as β-lactams with good antianaerobic activity are frequent alternatives to combination regimens such as aminoglycosides or aztreonam plus an antianaerobic agent such as clindamycin or metronidazole. The major issues in selecting a regimen are relative efficacy, potential for adverse drug effects, and cost. Single agents are clearly equivalent to combinations in preventing infectious complications after penetrating abdominal trauma and in treating established intraabdominal infections of mild to moderate severity or in relatively low-risk patients. A few trials demonstrated their equivalency in patients at high risk of mortality, although experience is limited. Single-agent regimens may reduce the risks of adverse drug effects compared with combination regimens, but they are not always less expensive.  相似文献   
73.
Summary Measurement of biotransformation activities in cells is of great importance for drug metabolism and toxicologic studies. It is currently done by measuring the enzymatic activities in partially purified microsomes. In the present work we report on a rapid, easy, sensitive, and reproducible fluorimetric assay for quantifying cytochrome P450-dependent monooxygenase activities (P450IA1, P450IIB1) in hepatocytes cultured in 96-well plates. The procedure involves the direct determination of enzymatic activities in intact hepatocytes while avoiding cell homogenization, thereby permitting use of a the reduced number of cells and allowing cultured cells to be used in later experiments. Substrates (7-ethoxyresorufin, 7-pentoxyresorufin) are added to culture medium and metabolized by hepatocytes. After enzymatic deconjugation, the fluorescent resorufin present in culture medium is quantified by means of a microplate fluorimetric reader. Major advantages of this technique, as compared to other available methods, are: a) no cell disruption is required; b) activity can be measured with a very small number of cells; c) rapid processing time; and d) possibility of performing repeated assays with the same cell monolayer.  相似文献   
74.
75.

Background  

A wide range of outcomes have been assessed in trials of interventions for carpal tunnel syndrome (CTS), however there appears to be little consensus on what constitutes the most relevant outcomes. The purpose of this systematic review was to identify the outcomes assessed in randomized clinical trials of surgical interventions for CTS and to compare these to the concepts contained in the International Classification of Functioning, Disability and Health (ICF).  相似文献   
76.
BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most prevalent fatal cancers in the world. Despite advances in early diagnosis and improvements in surgical techniques, the survival of patients with HCC even after resection is poor because of the high incidence of recurrences. Therefore, the identification of prognostic factors may be helpful in the development of new treatment protocols. AIMS: To investigate HER-2/neu status in HCC by immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH), and to explore the possibility of using trastuzumab in the treatment of HCC. METH ODS: Eight hundred and sixty eight surgical samples from patients with primary HCC were examined for their HER-2/neu status. IHC for HER-2/neu was performed with the HercepTest kit; FISH analysis was performed with the PathVysion HER-2 DNA probe kit. The correlations between HER-2/neu overexpression and clinicopathological characteristics were analysed statistically. RESULTS: HER-2/neu overexpression was detected in 21 (2.42%) of the 868 primary HCCs. Only one specimen showed HER-2/neu gene amplification by FISH. No significant associations were found between HER-2/neu overexpression and the clinicopathological parameters. CONCLUSIONS: There is a low frequency of HER-2/neu overexpression/amplification in HCC. There appears to be no role for HER-2/neu as a prognostic marker and no benefit of anti-HER-2/neu trastuzumab treatment in patients with HCC.  相似文献   
77.
A study of some antiparasitic properties of several homoallylamines and related tetrahydroquinolines and quinolines, previously described, was carried out using in vitro activity assays against the epimastigote form of Trypanosoma cruzi and against Trichomonas vaginalis. Unspecific cytotoxicity against murine macrophages was also studied. Although the antichagasic and trichomonacidal activities are not comparable to those of the standard drugs, nifurtimox and metronidazole, some of the compounds exhibit an interesting specific antiparasitic activity.  相似文献   
78.
A neonate vaccinated against HBV was the source of an occupational exposure to blood. She was tested for hepatitis B surface antigen and found to be positive, leading to unnecessary treatment, retesting, and concern. Evaluation of the infectious status of HBV should rely on other means if vaccination has recently occurred.  相似文献   
79.
BACKGROUND: Bowel-associated dermatosis-arthritis syndrome denotes the occurrence of diarrhoea with arthritis and skin lesions related to bowel disease with or without bowel bypass. In this condition, the histological finding of cutaneous aseptic neutrophilic cell infiltrate is non-specific and common to a wide spectrum of neutrophilic dermatoses, including pyoderma gangrenosum. OBSERVATION: We describe a 78-year-old woman with fever, abdominal discomfort and arthralgias, who developed grouped pustular lesions on her shins with histologically spongiform pustule formation. Aetiological assessment disclosed diverticular disease with sigmoid stenosis. CONCLUSION: Although clinical and histological features in our case fit the diagnosis of bowel-associated dermatosis-arthritis syndrome, they may also correspond to a pustular variant of pyoderma gangrenosum. Our observation raises the question of the nosological classification of bowel-associated dermatosis-arthritis syndrome within the spectrum of neutrophilic diseases.  相似文献   
80.
Summary Genes involved in cancer generation are usually tumor suppressors and oncogenes. Progressive genetic alterations in these genes are involved in the mechanisms of tumorigenesis. In prostate cancer, additionally several chromosomal loci that should harbor mutated genes have been proposed. Some genes have been found altered in prostate cancer, such as PTEN, TP53, AR, RNASEL (HPC1), ELAC2 (HPC2), CDKN2A and MSR1 and those can be natural targets for new strategies of treatment. Besides, gene therapy has been suggested to be suitable for prostate cancer treatment. This approach includesex vivo corrective therapy, suicide, and antisense therapy.  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