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   22207篇
  免费   1171篇
  国内免费   115篇
耳鼻咽喉   240篇
儿科学   480篇
妇产科学   480篇
基础医学   2889篇
口腔科学   582篇
临床医学   1811篇
内科学   5843篇
皮肤病学   547篇
神经病学   1919篇
特种医学   607篇
外科学   3562篇
综合类   113篇
现状与发展   1篇
一般理论   4篇
预防医学   1533篇
眼科学   408篇
药学   1061篇
中国医学   43篇
肿瘤学   1370篇
  2023年   170篇
  2022年   378篇
  2021年   821篇
  2020年   363篇
  2019年   710篇
  2018年   838篇
  2017年   476篇
  2016年   504篇
  2015年   592篇
  2014年   785篇
  2013年   1092篇
  2012年   1781篇
  2011年   1698篇
  2010年   988篇
  2009年   918篇
  2008年   1440篇
  2007年   1467篇
  2006年   1397篇
  2005年   1367篇
  2004年   1111篇
  2003年   1066篇
  2002年   1015篇
  2001年   188篇
  2000年   134篇
  1999年   188篇
  1998年   158篇
  1997年   161篇
  1996年   130篇
  1995年   135篇
  1994年   116篇
  1993年   96篇
  1992年   85篇
  1991年   81篇
  1990年   60篇
  1989年   63篇
  1988年   48篇
  1987年   51篇
  1986年   52篇
  1985年   51篇
  1984年   50篇
  1983年   32篇
  1982年   32篇
  1981年   49篇
  1980年   36篇
  1979年   47篇
  1978年   48篇
  1977年   31篇
  1976年   43篇
  1975年   33篇
  1974年   31篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
41.
42.
We measured platelet-rich plasma (PRP) serotonin in patients suffering from tension-type headache, before and after treatment with amitriptyline, comparing them with a healthy control group and patients with untreated depression. We evaluated the severity of headache and depression in each group. PRP serotonin levels were higher in patients with headache than in controls and depressed patients. We observed a fall of PRP serotonin in patients with tension-type headache to similar levels after treatment as the depressed group. This fall was correlated with the improvement of headache but not with depression scales. Our data suggest that the rise of platelet serotonin levels in tension-type headache is related to pain and not depression.  相似文献   
43.
44.
45.
46.
Ossifying fibromyxoid tumor of soft parts   总被引:1,自引:0,他引:1  
Ossifying fibromyxoid tumors (OFT) of soft parts are very rare neoplasms recently described by Enzinger et al. (1). They usually present as well-circumscribed, slow-growing, asymptomatic subcutaneous masses. A characteristic finding is a fibrous capsule and an incomplete peripheral shell of mature bone. Although most cases behave as benign tumors, a high rate of local recurrences have been described. We describe a 43-year-old male with a perianal subcutaneous tumor of 10 years evolution. The histopathology was compatible with OFT. Due to the subcutaneous location of OFF, both the dermatologist and dermatopathologist need to know about this rare tumor.  相似文献   
47.
The xanthine, hypoxanthine, and total oxypurine levels were determined in the CSF of 28 hydrocephalic patients (age from newborn to 2 years) and 8 healthy controls using HPLC. The Evans' index, the mean weekly increase in cranial circumference, and the intracranial pressure were also measured. Of the hydrocephalic patients 13 were self-compensated and the other 15 had a shunt implanted during the course of the study. The mean xanthine, hypoxanthine, and total oxypurine levels in the normal children were 5.20, 5.94, and 11.29 mol/l, respectively. In the self-compensated hydrocephalics these levels were 5.17, 5.71, and 10.79 mol/l, respectively. In the noncompensated hydrocephalics, they were 9.90, 9.91, and 19.82 mol/l. The differences between the latter group and the first two are statistically significant (P<0.001). The mean Evans' index and the mean weakly increase in cranial circumference in the self-compensated hydrocephalics were 0.35 and 0.25 cm, respectively. In the noncompensated hydrocephalics, they were 0.55 and 0.95 cm. The differences between the two groups are statistically significant (P<0.001). Two weeks after implantation of shunts in the noncompensated cases, the mean xanthine, hypoxanthine, and total oxypurine levels fell to 4.22, 4.57, and 8.80 mol/l, respectively. These changes are statistically significant (P<0.001). We think that the two criteria (clinical and biochemical) are equally useful for the prediction of self-compensation in hydrocephalic children and that the oxypurine values after shunt implantation can be used to monitor progress in noncompensated cases.  相似文献   
48.
Summary Hypertension was induced in uninephrectomized rats by NaCl 0.9% drinking and deoxycorticosterone acetate (DOCA) administration for 6 weeks. Plasma renin activity was markedly reduced but not suppressed. Renal renin concentration and total renal renin content were moderately reduced. Intravenous injection of 0.2 ml of antiangiotensin plasma resulted in transitory hypotension both in salt and DOCA-treated rats, and in normotensive control rats. It is concluded that angiotensin participates in the maintenance of blood pressure in salthypertensive rats as well as in normal animals.This work was supported by grant 67-00-517 from D.G.R.S.T. (Délégation Générale à la Recherche Scientifique et Technique). The authors wish to thank Miss colette Innocenzi and Miss Sonia Culot for technical assistance.  相似文献   
49.
Harmaline inhibition of sodium uptake and of sodium-dependentd-glucose transport was investigated using brush-border membrane vesicles from frozen rabbit jejunum. Under sodium-gradient conditions, initiald-glucose uptake (20 s) was inhibited by harmaline at concentrations above 0.5 mM, but at lower harmaline concentrationsd-glucose uptake was stimulated by 10–15%. When a similar potassium gradient was used, harmaline had no effect. At concentrations upt to 2 mM, harmaline did not alter the equilibrium uptake ofd-glucose ord-mannitol. After pre-equlibration with sodium (25 mM),d-glucose uptake was inhibited at harmaline concentrations ranging from 0.1 to 2 mM. Sodium (10 mM) uptake was also inhibited by harmaline. Increasing the sodium concentration reduced the inhibitory effect of harmaline on tracer sodium uptake as well as on sodium-dependentd-glucose uptake. Similar to phlorizin, harmaline (1 mM) was able to prevent glucose-induced sodium influx across the brush-border membrane.Sodium uptake into brush-border membrane vesicles seems to be inhibited at lower harmaline concentrations than sodium-dependentd-glucose uptake. At high (2 mM) inhibitor concentrations, however, sodium-dependent glucose uptake is more strongly inhibited than sodium uptake. These results suggest that harmaline inhibits both sodium and sodium-dependent transport across intestinal brush-border membranes by interacting with specific sodium-binding sites.  相似文献   
50.
Recent research has shown that pseudowords created by transposing letters are very effective for activating the lexical representation of their base words (e.g., relovution activates REVOLUTION). Furthermore, pseudoword transpositions of consonants are more similar to their corresponding base words than the transposition of vowels. We report one experiment using pseudowords created by the transposition of two consonants, two vowels, and their corresponding control conditions (i.e., the replacement of two consonants or two vowels) in a lexical decision task while Event Related Potentials (ERPs) were recorded. The results showed a modulation of the amplitude of the N400 component as a function of the type of pseudoword (transposed-letter versus replacement letter pseudowords), and this modulation was different for transposed consonants and vowels. These results suggest that consonants and vowels play a different role during word processing.  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