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   104102篇
  免费   42555篇
  国内免费   151篇
耳鼻咽喉   1826篇
儿科学   5007篇
妇产科学   1214篇
基础医学   18545篇
口腔科学   6027篇
临床医学   14383篇
内科学   28927篇
皮肤病学   8108篇
神经病学   14751篇
特种医学   3156篇
外国民族医学   13篇
外科学   18219篇
综合类   747篇
现状与发展   2篇
一般理论   35篇
预防医学   6039篇
眼科学   2023篇
药学   7876篇
中国医学   1154篇
肿瘤学   8756篇
  2023年   372篇
  2022年   1136篇
  2021年   2798篇
  2020年   5804篇
  2019年   11796篇
  2018年   11452篇
  2017年   12206篇
  2016年   12916篇
  2015年   12703篇
  2014年   12953篇
  2013年   13848篇
  2012年   6255篇
  2011年   6237篇
  2010年   10068篇
  2009年   6320篇
  2008年   3440篇
  2007年   2289篇
  2006年   2211篇
  2005年   1907篇
  2004年   1819篇
  2003年   1547篇
  2002年   1604篇
  2001年   1135篇
  2000年   1067篇
  1999年   559篇
  1998年   219篇
  1997年   149篇
  1996年   134篇
  1995年   122篇
  1994年   96篇
  1993年   82篇
  1992年   83篇
  1991年   92篇
  1990年   71篇
  1989年   85篇
  1988年   70篇
  1987年   66篇
  1986年   68篇
  1985年   74篇
  1984年   115篇
  1983年   106篇
  1982年   63篇
  1981年   61篇
  1980年   70篇
  1979年   76篇
  1978年   60篇
  1977年   53篇
  1976年   52篇
  1975年   59篇
  1974年   36篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
105.
106.
BACKGROUND: Sevelamer hydrochloride was recently proposed as a phosphate binder to prevent hypercalcaemia in place of calcium alkaline salts in dialysis patients. So far, it has been evaluated only in patients receiving calcitriol, without comparison with CaCO(3) alone, although the latter was found to be as effective as the combination of calcitriol and Al(OH)(3) in suppressing parathyroid hormone (PTH) without inducing hypercalcaemia and to have a better lowering effect on serum phosphate. Moreover, this bile salt binder may decrease serum 25-OH vitamin D. Therefore, we compared for 5 months two strategies for controlling moderate hyperparathyroidism: CaCO(3) alone vs sevelamer in conjunction with measures to increase calcium balance. METHODS: Forty-two patients were randomized: 21 continued their treatment with 4.8 g/day CaCO(3) and 21 were switched to sevelamer (initial dose: 2.4 g/day, increased to 4.4 g/day). Each month, when serum-corrected calcium decreased below 2.30 mmol/l, dialysate calcium was increased or alphacalcidol was given at each dialysis session, according to serum PO(4) levels. The following parameters were monitored: serum Ca, PO(4), bicarbonate and protein, weekly; and serum PTH, 25-OH vitamin D and total, LDL and HDL cholesterol monthly. RESULTS: Except for higher serum phosphate at month 1, lower serum bicarbonate at month 2 and lower LDL cholesterol at month 5 in the sevelamer group, no difference was found between the two groups. Compared with baseline levels, PTH increased and 25-OH vitamin D decreased significantly in both groups, these two parameters being inversely correlated. CONCLUSIONS: Given comparable control of plasma calcium, phosphate and 25-OH vitamin D, PTH control is comparable in both strategies. Sevelamer does not induce greater vitamin D depletion than CaCO(3). The transient decrease of serum bicarbonate after discontinuation of CaCO(3) in the sevelamer group suggests a less optimal prevention of acidosis. The sevelamer-induced decrease in LDL cholesterol gives this drug a potential advantage in cardiovascular prevention.  相似文献   
107.
Geographical variations in the incidence of disease are of considerable theoretical and practical importance. It has been claimed that the distribution of acute lymphoblastic leukemia (ALL) phenotypes in Saudi Arabia is different from that recorded in the Western literature. One hundred and twelve (112) patients under 15 years of age, diagnosed as ALL between January 1992 and May 1994 had immunophenotypes performed on their blast cells. Common ALL (cALL) together with pre-B-ALL, formed 86.5% of the total; B-cell 3%, T-cell 6% and null cell 4.5%. These figures are not significantly different from the Western literature. A previous claim from this institution in 1990, that both null and B-cell ALL were significantly increased compared with elsewhere, is not supported by the present figures. Age and sex distribution, and FAB classification, L1 77%, L2 20% and L3 3%, were also of the same order as described elsewhere and, in particular, there was no increase in the frequency of L3 subtype.  相似文献   
108.
Nasopharyngeal angiofibromas occur predominantly in males in their puberty and adolescence; the incidence in other age groups and in women is exceptional. This report describes a case of a 57-year-old woman with nasopharyngeal angiofibroma presenting typical radiological findings in computed tomography, MR imaging and angiography. The tumour was successfully removed and histopathological examination confirmed the diagnosis. In 6 years follow-up the patient is free of symptoms.  相似文献   
109.
Early therapeutic alliance is usually measured by the rating of a single session (between the third and the fifth sessions). However, there is a strong argument in favor of viewing early alliance as a developing process. This study examined the relationship between patient's rating of the helping alliance (HAq) at each session and therapy outcome. This comparison was repeated using patterns of alliance over the course of treatment. Patterns of therapeutic alliance development were detected by clustering ratings of a sample of N = 70 outpatients across four sessions of very brief psychotherapeutic intervention. Cluster analysis revealed two main patterns (shapes) of alliance development: (i) stable alliance, and (ii) linear growth pattern. These patterns are more predictive of symptom improvement and social adjustment than single ratings, whereas single ratings measuring the strength of alliance are more correlated with patient's satisfaction. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
110.
An enzyme‐linked immunosorbent assay (ELISA) for the detection of porcine pepsin in milk‐clotting enzyme preparations has been developed. The assay is capable of detecting porcine pepsin in the range 1 μgto 1 mg ml‐1 without enhancement or modification. The specificity of the technique was studied by inhibition assay. Slight cross‐reactions with bovine rennet and Mucor miehei rennet occurred at high concentrations (1.0 mg ml‐1). The ELISA used in this investigation appears to provide a quick, sensitive and specific method for the detection of porcine pepsin and has potential applications in the dairy industry.  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