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   1067篇
  免费   68篇
  国内免费   8篇
耳鼻咽喉   2篇
儿科学   32篇
妇产科学   33篇
基础医学   73篇
口腔科学   55篇
临床医学   121篇
内科学   293篇
皮肤病学   55篇
神经病学   69篇
特种医学   77篇
外科学   108篇
综合类   30篇
一般理论   3篇
预防医学   68篇
眼科学   6篇
药学   104篇
肿瘤学   14篇
  2019年   6篇
  2015年   12篇
  2014年   6篇
  2013年   28篇
  2012年   8篇
  2011年   10篇
  2010年   26篇
  2009年   23篇
  2008年   19篇
  2007年   14篇
  2005年   6篇
  2003年   6篇
  2002年   5篇
  2001年   9篇
  1999年   13篇
  1998年   28篇
  1997年   50篇
  1996年   59篇
  1995年   36篇
  1994年   37篇
  1993年   44篇
  1992年   17篇
  1991年   34篇
  1990年   23篇
  1989年   30篇
  1988年   27篇
  1987年   28篇
  1986年   21篇
  1985年   20篇
  1984年   13篇
  1983年   29篇
  1982年   24篇
  1981年   26篇
  1980年   15篇
  1979年   16篇
  1978年   11篇
  1977年   5篇
  1976年   8篇
  1975年   6篇
  1971年   13篇
  1970年   7篇
  1963年   13篇
  1959年   22篇
  1958年   39篇
  1957年   35篇
  1956年   40篇
  1955年   26篇
  1954年   26篇
  1949年   28篇
  1948年   21篇
排序方式: 共有1143条查询结果,搜索用时 31 毫秒
51.
52.
W. J. RUSSELL 《Anaesthesia》1983,38(11):1062-1065
In a double-blind controlled trial of male patients undergoing transurethral resection of the prostate, oral lorazepam was assessed against a placebo. The same anaesthetist performed all spinal blocks and made all assessments. The patients who received lorazepam had substantial amnesia for the operation and were drowsier, but remained cooperative during the procedure. Patient anxiety as assessed by the anaesthetist and as recalled by the patient was decreased, although anxiety assessment by linear analogue was the same for both groups. Lorazepam significantly increased the patient acceptability of spinal anaesthesia.  相似文献   
53.
54.
55.
56.
We have studied several biochemical indices of bone turnover and vitamin D metabolism in 32 untreated patients with Paget's disease and in 32 age-matched control subjects. patients with Paget's disease, as expected, were characterized by high bone turnover, as judged by alkaline phosphatase and urinary excretion of hydorxyproline. Serum values of 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) and the ratio of 24,25(OH)2D3 to 25-OHD were significantly lower in patients than in control subjects. Serum concentrations of 1,25(OH)2D3 were normal in Paget's disease. The distribution of values for 24,25(OH)2D3 was log normal. On the basis of the normal range computed from control subjects, patients were divided into those with low or normal values for 24,25(OH)2D3. Disease activity, as judged by biochemical indices was significantly higher in the patients with the lower values of 24,25(OH)2D3. We conclude that Paget's disease is characterized by low circulating concentrations of 24,25(OH)2D3, particularly in patients with more extensive or severe disease.  相似文献   
57.
58.
美国约有30%的糖尿病患者(约620万人)被漏诊。超过25%的新诊断糖尿病患者已经患有糖尿病视网膜病变或出现微量白蛋白尿,这意味着患者在2型糖尿病发病和确诊之间被“忽视”了7年。有时发现在糖尿病前期,即空腹血糖(FPG)略有偏高(IFG,空腹血糖受损)或口服葡萄糖耐量试验(OGTT)略有偏高,甚至已存在微血管和大血管并发症。  相似文献   
59.
Spermatogenesis in the platypus ( Ornithorhynchus anatinus ) is of considerable biological interest as the structure of its gametes more closely resemble that of reptiles and birds than marsupial or eutherian mammals. The ultrastructure of 16 steps of spermatid development is described and provides a basis for determining the kinetics of spermatogenesis. Steps 1–3 correspond to the Golgi phase of spermatid development, steps 4–8 correspond to the cap phase, steps 9–12 are the acrosomal phase, and steps 13–16 are the maturation phase. Acrosomal development follows the reptilian model and no acrosomal granule is formed. Most other features of spermiogenesis are similar to processes in reptiles and birds. However, some are unique to mammals. For example, a thin, lateral margin of the acrosome of platypus sperm expands over the nucleus as in other mammals, and more than in reptiles and birds. Also, a tubulobulbar complex develops around the spermatid head, a feature which appears to be unique to mammals. Further, during spermiation the residual body is released from the caudal end of the nucleus of platypus sperm leaving a cytoplasmic droplet located at the proximal end of the middle piece as in marsupial and eutherian mammals. Other features of spermiogenesis in platypus appear to be unique to monotremes. For example, nuclear condensation involves the formation of a layer of chromatin granules under the nucleolemma, and development of the fibrous sheath of the principal piece starts much later in the platypus than in birds or eutherian mammals.  相似文献   
60.
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