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   2637116篇
  免费   199244篇
  国内免费   4989篇
耳鼻咽喉   37789篇
儿科学   83925篇
妇产科学   76060篇
基础医学   371006篇
口腔科学   79553篇
临床医学   229096篇
内科学   512031篇
皮肤病学   58373篇
神经病学   212631篇
特种医学   105318篇
外国民族医学   879篇
外科学   403730篇
综合类   64339篇
现状与发展   9篇
一般理论   918篇
预防医学   195791篇
眼科学   62109篇
药学   199349篇
  7篇
中国医学   5390篇
肿瘤学   143046篇
  2018年   24047篇
  2015年   24240篇
  2014年   33660篇
  2013年   51626篇
  2012年   68627篇
  2011年   72533篇
  2010年   43078篇
  2009年   41247篇
  2008年   69666篇
  2007年   74523篇
  2006年   75499篇
  2005年   73426篇
  2004年   71905篇
  2003年   69338篇
  2002年   68136篇
  2001年   122296篇
  2000年   126048篇
  1999年   107350篇
  1998年   29261篇
  1997年   26614篇
  1996年   26102篇
  1995年   25090篇
  1994年   23587篇
  1993年   22129篇
  1992年   86561篇
  1991年   83934篇
  1990年   82176篇
  1989年   80078篇
  1988年   74556篇
  1987年   73399篇
  1986年   70078篇
  1985年   67224篇
  1984年   50358篇
  1983年   43236篇
  1982年   25665篇
  1981年   23211篇
  1980年   21748篇
  1979年   48270篇
  1978年   34031篇
  1977年   29065篇
  1976年   26820篇
  1975年   29305篇
  1974年   35464篇
  1973年   34209篇
  1972年   32028篇
  1971年   30117篇
  1970年   28131篇
  1969年   26724篇
  1968年   24848篇
  1967年   22376篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Follicular fluids from eight patients with one ovary and from ten patients with two ovaries were investigated for bioactive inhibin, total renin, oestradiol (E2) and progesterone (P4) concentrations. Four follicular fluids were pooled per patient before assessment. All women had been stimulated similarly using a protocol including a GnRH agonist, HMG and HCG. Renin levels were significantly lower and P4 significantly higher in pools of follicular fluid from patients with one ovary, whereas inhibin and E2 concentrations were similar in both patient groups. A significant negative correlation was found in the pools of follicular fluid between inhibin and E2 in both groups. These results suggest a role for inhibin and renin in the paracrine and autocrine control of stimulated follicular development.  相似文献   
993.
A review of the pathological material from 42 children with non-Hodgkin's lymphoma seen over a 44 month period revealed 10 large cell tumours. Of these, six were classified as peripheral T-cell lymphoma, an entity rarely reported in childhood. Three patients were boys and three girls (median age 9.5 years), and extranodal presentation was a feature of two patients. Five had high-grade tumours; of these, three were classified as large cell anaplastic, Ki-1 positive and two as pleomorphic large cell. The remaining patient had a low-grade tumour of angioimmunoblastic type. T-cell subsets were examined in three cases and showed the following phenotypes: CD4-, CD8-; CD4+, CD8-; CD4-, CD8+. Three of the patients with high-grade tumours died, with a mean survival of 22 weeks. The remaining patients are alive and clinically disease-free for between 10 and 24 months after treatment.  相似文献   
994.
995.
Potential roles of protease inhibitors in Alzheimer's disease   总被引:1,自引:0,他引:1  
C R Abraham 《Neurobiology of aging》1989,10(5):463-5; discussion 477-8
Recently, protease inhibitors have been recognized as potential contributors to the pathogenesis of Alzheimer's disease. In this role, they could mediate an exaggerated regenerative response in the brain, participate as acute phase reactants, or be involved in the aberrant proteolytic processing of the amyloid proteins. Protease inhibitors are, therefore, attractive targets for drug intervention in Alzheimer's disease.  相似文献   
996.
The cytoskeleton is susceptible to oxidative stress and this occurs prior to membrane blebbing and cell lysis. Vimentin intermediary filaments in rheumatoid synoviocytes are more susceptible than in normal synoviocytes and this may have pathological significance. They are however no more susceptible to heat shock than other cell types.  相似文献   
997.
A trial of Thyrotropin Releasing Hormone (TRH) 5.0 mg/kg body weight subcutaneously every other day for two weeks produced transient increased tone in muscles, along with other (side-) effects in patients with Amyotrophic Lateral Sclerosis (ALS). One patient's extensor plantar transiently changed to a flexor plantar reflex after injection, probably due to disproportionate increase in tone of the calf muscles. No significant changes in F-waves or H-reflexes were seen. No increase in useful voluntary strength, or in strength measured by Medical Research Council (MRC) testing or strain gauge isometric strength testing was seen. However, dyspnea was seen within 10 minutes of TRH injection.  相似文献   
998.
We report on results of lysostrip experiments designated to analyse the molecular relations between DQ and DR antigens. The purpose of lysostrip application was to determine whether these antigens can independently be redistributed on B-cell surface by incubation with a specific antibody followed by incubation with F(ab')2 fragments of rabbit antihuman Ig. The obtained results have clearly shown that DQ antigens, and supertypic and narrow DR antigens, move independently, indicating that they are located on separate molecules, supporting the concept of different DQ and DR loci.  相似文献   
999.
This paper describes the first application of structural modeling to neuroscience. Structural modeling (also known as path analysis) is a method to assess the relative impact of directional links in a system and how these interrelations may change under different conditions. The objective was to demonstrate how structural modeling can be used to determine the functional interrelationships between brain structures that form the auditory system. Using structural modeling, changes in auditory system 2-DG uptake were examined during long- and short-term habituation of the acoustic startle reflex. Models were based on the anatomical connections between central auditory system structures. Using functional 2-DG data, the correlations between these structures were calculated and numerical weights were computed for each anatomical link. The analysis revealed that the lemniscal path was dominant during short-term habituation, while during long-term habituation this influence was modified through extra-lemniscal pathways. The models are discussed in the context of previous findings to demonstrate how structural modeling can not only complement, but also extract more information from 2-DG mapping experiments.  相似文献   
1000.
In a phase I-II study, 21 patients with relapsed or refractory acute leukemia were treated with 4'-deoxydoxorubicin (esorubicin), the 4'-deoxy derivative of doxorubicin. Four of 14 evaluable patients with acute nonlymphocytic leukemia (ANLL) in relapse or refractory to other anthracyclines achieved partial response (28.5%). Pharmacokinetics were similar to those of the parent compound, doxorubicin. Esorubicin has activity in ANLL and has pharmacologic properties comparable to those of other anthracyclines. Dose-limiting toxicity occurs in the form of mucositis, which may limit its use in combination with other antileukemic drugs.  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