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   23483篇
  免费   1655篇
  国内免费   82篇
耳鼻咽喉   257篇
儿科学   1556篇
妇产科学   449篇
基础医学   3286篇
口腔科学   499篇
临床医学   2628篇
内科学   4557篇
皮肤病学   422篇
神经病学   1978篇
特种医学   761篇
外国民族医学   18篇
外科学   3283篇
综合类   492篇
一般理论   25篇
预防医学   1854篇
眼科学   341篇
药学   1313篇
中国医学   45篇
肿瘤学   1456篇
  2023年   103篇
  2022年   141篇
  2021年   312篇
  2020年   249篇
  2019年   419篇
  2018年   665篇
  2017年   509篇
  2016年   532篇
  2015年   455篇
  2014年   612篇
  2013年   818篇
  2012年   1471篇
  2011年   3151篇
  2010年   1414篇
  2009年   936篇
  2008年   1213篇
  2007年   1250篇
  2006年   1086篇
  2005年   1126篇
  2004年   992篇
  2003年   916篇
  2002年   795篇
  2001年   510篇
  2000年   534篇
  1999年   463篇
  1998年   243篇
  1997年   203篇
  1996年   195篇
  1995年   188篇
  1994年   161篇
  1993年   141篇
  1992年   294篇
  1991年   283篇
  1990年   245篇
  1989年   258篇
  1988年   200篇
  1987年   197篇
  1986年   190篇
  1985年   181篇
  1984年   153篇
  1983年   119篇
  1982年   79篇
  1981年   69篇
  1979年   97篇
  1978年   62篇
  1976年   66篇
  1975年   67篇
  1974年   74篇
  1973年   62篇
  1972年   75篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
201.
In Saccharomyces cerevisiae cells a number of genes are required for progression through, or else to pass beyond, the G1 phase. We characterized a novel gene, RPG1, which is also involved in this phase. RPG1 is an essential gene encoding a 110-kDa evolutionarily conserved protein. Elutriated or α-factor-synchronized cells of the rpg1-1 temperature-sensitive mutant were arrested in the first cell cycle when shifted to a non-permissive temperature. The cells remained unbudded and neither grew nor duplicated DNA. rpg1-1 cells synchronized in S phase completed mitosis and arrested as unseparated G1 cells after a shift to a non-permissive temperature. Similarly, the asynchronous rpg1-1 cells accumulated in G1 at the non-permissive temperature, but mother and daughter cells did not separate. A bulk of Calcofluor-stained material was localized in the region adjacent to the cell septum. Our data show that Rpg1p is required for passage through the G1 phase and may be involved in growth control. Data published recently indicate that Rpg1p exhibits significant sequence similarity to a subunit of the mammalian translation initiation factor 3. Received: 6 October 1997 / 8 November 1997  相似文献   
202.
203.
Summary Twenty three patients with essential hypertension who were uncontrolled on diuretic and/or -receptor antagonist therapy were treated additionally with the vasodilator, pinacidil, in an open study. Significant reduction in mean blood pressure was achieved. Supine and erect systolic and diastolic blood pressure fell by 44/25 mmHg and 37/24 mmHg respectively over the study period of 12 weeks. Side-effects such as dizziness, headache, facial flushing and mild oedema were experienced by 10 patients during the study, all of which were mild and transient and did not require withdrawal from pinacidil therapy. Pinacidil is an effective and well tolerated agent in the treatment of essential hypertension.  相似文献   
204.
Summary The expression of transferrin receptors (TFR) by normal and neoplastic urothelial cells was studied in control patients and in patients with transitional cell carcinoma of the bladder. These tumours were graded independently and consisted of 19 grade I, 30 grade II and 19 grade III lesions. TFRs were identified using a monoclonal antibody specific for TFR (OKT9) in an immunofluorescent or avidin/biotin-immunoperoxidase technique on fresh frozen sections. TFRs were not detected on normal urothelium. However, positive staining was found to increase with increasing pathological grade and stage of the tumours, ranging from 31.6% of grade I to 78.9% of grade III tumours and 51.2% of pTa (mucosa only lesions) to 87.5% of pT2/pT2+ (muscle invasion±deeper) primary urothelial malignancies.  相似文献   
205.
The behavioral effects following intrastriatal MPP+, the neurotoxic metabolite of MPTP, were evaluated in mice. Bilateral injections of 10 cro;g MPP+ to mice previously trained in the shuttle box paradigm produced a 66% decrease in striatal dopamine and significant deficits in all measures of conditioned avoidance responding. In addition, although these mice showed no deficits in baseline rotorod performance, challenge with the cholinergic agonist oxotremorine revealed that MPP+-treated mice exhibited an increased sensitivity to the disruptive effects of the drug at each dose and time point. Finally, MPP+-treated mice also exhibited an increase in tremor induced by 0.1 and 0.15 mg/kg oxotremorine. These observations are discussed in reference to idiopathic parkinsonism.  相似文献   
206.
This paper compares evaluative research to program evaluation by defining and describing each. A case example using the scientific design and methodology of evaluative research to evaluate a specific community mental health program is also presented. Project design is discussed in light of the awareness that the mental health needs of communities do not always bend to fit the requisite of precise scientific procedure. Some ideas on methodological considerations reflect that normal research tools can be useful to achieve a valid study. Implications for the application of evaluative research to community mental health needs are also identified.  相似文献   
207.
Maternal and Child Health Journal - The purpose of this study was to explore socio-ecological influences affecting the daily lives of urban, pregnant Puerto Rican women and factors negatively...  相似文献   
208.

Background  

The longterm outlook afterHelicobacter pylori (H. pylori) eradication in peptic ulcer disease is unclear.  相似文献   
209.
210.
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