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   2637318篇
  免费   199252篇
  国内免费   4989篇
耳鼻咽喉   37833篇
儿科学   83926篇
妇产科学   76060篇
基础医学   371027篇
口腔科学   79554篇
临床医学   229099篇
内科学   512069篇
皮肤病学   58373篇
神经病学   212640篇
特种医学   105325篇
外国民族医学   879篇
外科学   403744篇
综合类   64341篇
现状与发展   9篇
一般理论   918篇
预防医学   195804篇
眼科学   62111篇
药学   199392篇
  7篇
中国医学   5390篇
肿瘤学   143058篇
  2018年   24054篇
  2015年   24245篇
  2014年   33665篇
  2013年   51632篇
  2012年   68644篇
  2011年   72540篇
  2010年   43084篇
  2009年   41258篇
  2008年   69678篇
  2007年   74539篇
  2006年   75513篇
  2005年   73439篇
  2004年   71909篇
  2003年   69352篇
  2002年   68153篇
  2001年   122299篇
  2000年   126054篇
  1999年   107351篇
  1998年   29262篇
  1997年   26615篇
  1996年   26102篇
  1995年   25091篇
  1994年   23588篇
  1993年   22129篇
  1992年   86559篇
  1991年   83931篇
  1990年   82175篇
  1989年   80077篇
  1988年   74558篇
  1987年   73398篇
  1986年   70077篇
  1985年   67230篇
  1984年   50357篇
  1983年   43236篇
  1982年   25665篇
  1981年   23212篇
  1980年   21748篇
  1979年   48271篇
  1978年   34033篇
  1977年   29064篇
  1976年   26820篇
  1975年   29305篇
  1974年   35464篇
  1973年   34211篇
  1972年   32026篇
  1971年   30118篇
  1970年   28131篇
  1969年   26726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 0 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