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   235131篇
  免费   20384篇
  国内免费   5835篇
耳鼻咽喉   3328篇
儿科学   4271篇
妇产科学   3735篇
基础医学   18713篇
口腔科学   7265篇
临床医学   21273篇
内科学   25237篇
皮肤病学   2433篇
神经病学   11593篇
特种医学   6193篇
外国民族医学   53篇
外科学   23928篇
综合类   38062篇
现状与发展   10篇
一般理论   24篇
预防医学   29195篇
眼科学   2090篇
药学   22118篇
  370篇
中国医学   27427篇
肿瘤学   14032篇
  2024年   1018篇
  2023年   4580篇
  2022年   8619篇
  2021年   11362篇
  2020年   11066篇
  2019年   12302篇
  2018年   10741篇
  2017年   9471篇
  2016年   8671篇
  2015年   8163篇
  2014年   15512篇
  2013年   16079篇
  2012年   13972篇
  2011年   14958篇
  2010年   12090篇
  2009年   10480篇
  2008年   9894篇
  2007年   10170篇
  2006年   8571篇
  2005年   7380篇
  2004年   6127篇
  2003年   5409篇
  2002年   4311篇
  2001年   3736篇
  2000年   3337篇
  1999年   2696篇
  1998年   2239篇
  1997年   1958篇
  1996年   1698篇
  1995年   1665篇
  1994年   1489篇
  1993年   1287篇
  1992年   1168篇
  1991年   1069篇
  1990年   935篇
  1989年   903篇
  1988年   830篇
  1987年   707篇
  1986年   607篇
  1985年   1874篇
  1984年   2142篇
  1983年   1350篇
  1982年   1773篇
  1981年   1233篇
  1980年   1068篇
  1979年   938篇
  1978年   766篇
  1977年   583篇
  1976年   718篇
  1975年   493篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
The aetiology of Klinefelter's Syndrome is not known. The causative factor(s) must explain the hypogonadism, low androgen levels, the disordered carbohydrate metabolism and the commonly associated psychiatric conditions. A biotin deficient/dependent state can account for the above. A biotin deficient Klinefelter's Syndrome patients with the above is described. The possible role of biotin in the primary, secondary and tertiary prevention of Klinefelter's Syndrome needs further research.  相似文献   
92.
The effects of haloperidol on motor and functioning and cognitive functioning were studied in young (3-5 months old) and aged (20-22 months old) male mice by examining haloperidol-induced catalepsy and haloperidol-induced decrements in performance on a radial arm maze. The aged mice were much more sensitive to these adverse effects of haloperidol than were the young mice. Studies of the distribution of radioactivity from [3H]haloperidol to the brain indicated that the differences in sensitivity to this drug were not due to pharmacokinetic differences. The results demonstrate that mice are suitable for studies of aging-induced changes in the behavioral effects of neuroleptic agents.  相似文献   
93.
94.
高等医学院校医学化学教材改革的几点思考   总被引:2,自引:1,他引:1  
医学的发展已进入分子水平,医学生必须具有扎实的化学基础才能适应专业学习及临床、科研工作的需要。现行医学化学教材大多沿用几十年前的模式,部分内容陈旧滞后,实用性不强。面对现实,改革势在必行。我们认为,突出重点、注重实用、体现医学特色应作为改革的方向。  相似文献   
95.
生物医学测量及控制技术新进展   总被引:2,自引:0,他引:2  
介绍生物医学测量及控制技术领域中的一些研究进展。  相似文献   
96.
The immunohistochemical occurrence of the high affinity neurotrophin (NT) receptors trkA, trkB, and trkC is shown in the pre-term newborn, infant, and adult human post-mortem cerebellum. Immunoreactive neuronal perikarya and processes were observed in all specimens examined, where they appeared unevenly distributed in the cerebellar cortical layers and deep nuclei, and showed regional differences among cerebellar lobules and folia. The trk receptor-antibodies, tested by Western blot on human cerebellum homogenates, revealed multiple immunoreactive bands for trkA and single bands for trkB and trkC. The results obtained show the tissue localization of the trk receptor-like immunoreactivity in the human cerebellum from prenatal to adult age. The analysis for codistribution of the receptors with the relevant ligand and among the receptors in discrete cortical and deep nuclei tissue fields shows a wide variety of conditions, from a good similarity in terms of type and density of labeled structures, to a lack of correspondence, and suggests the possibility of colocalization of trk receptors with the relevant neurotrophin and among them in the cerebellar cortex. These results sustain the concept that the neurotrophin trophic system participates in the development, differentiation, and maintenance of the human cerebellar connectivity and support the possibility of a multifactorial trophic support for the neurotrophins through target-derived and local mechanisms.  相似文献   
97.
98.
Abstract Changes in colonic motor activity during aerobic exercise were investigated in ten regularly exercising volunteers (five males and five females) aged 27–70 years. Motility was recorded with a catheter containing three solid-state pressure transducers spaced 5 cm apart. The motility catheter was advanced 40–50 cm from the anal verge by flexible sigmoidoscope without anesthesia at least 60 min prior to testing. Manometric recordings were made from the colon during a 1-h pre-exercise rest period, 1 h of jogging at 70–80% maximum heart rate, and 1-h post-exercise rest period. The dominant frequency of contractile activity in the colon shifted from 1–4 cpm during rest, to 4–9 cpm with the onset of exercise. Activity also shifted from sporadic, isolated contractions to regular, propagated contractions in six of ten subjects, five of whom reported a history of runner's diarrhoea. The dominant frequency returned to 1–4 cpm during the post-exercise period. These changes in distal colonie motility may account for the diarrhoea which some subjects experience during intense, acute exercise.  相似文献   
99.
A lymph node metastasis in the neck or parotid region from an unknown primary melanoma is an uncommon occurrence. Out of a total of 300 patients with head and neck melanoma treated at the Netherlands Cancer Institute between 1976 and 1992, 17 (5.7%) presented in this way. The most common site for metastatic lymph nodes (18 nodes in 17 patients) was level V (n= 7), followed by the parotid region (n= 4), level II (n= 4), level III (n= 2), and level IV (n= 7). Two patients had local excision of the neck node metastasis only, while the remaining 15 patients underwent more extensive surgical treatment. The 5-year disease-specific survival rate in this group was 48%, with a median survival of 36 months, which is more or less similar to the prognosis of stage II melanoma of the head and neck with a known, surgically treated primary tumour. No relation was found between disease-free interval and sex, the number of positive lymph nodes or the duration of symptoms.  相似文献   
100.
Abstract The major reason for late graft losses is chronic rejection. Recently, a large number of studies have indicated that proteolytic enzymes play an important role as mediators of glomerular injury. The cysteine proteinases cathepsins B and L degrade structural matrix proteins such as type I collagen and laminin. We investigated intraglomerular protease activities in 12 patients after kidney graftectomy because of end-tage renal disease following chronic rejection. A group of 12 patients undergoing nephrectomy because of cancer served as controls using only non-involved parts of the kidney. The activities of cathepsins B and L in homogenates of isolated glomeruli were measured fluorometrically methylcoumarylamidc substrates and related to DNA content. In rejected kidney allografts we observed significantly enhanced intraglomerular cathepsin B activity and cathepsin B + L activity.  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