全文获取类型
收费全文 | 21329篇 |
免费 | 1143篇 |
国内免费 | 112篇 |
专业分类
耳鼻咽喉 | 227篇 |
儿科学 | 435篇 |
妇产科学 | 472篇 |
基础医学 | 2729篇 |
口腔科学 | 586篇 |
临床医学 | 1638篇 |
内科学 | 5698篇 |
皮肤病学 | 525篇 |
神经病学 | 1906篇 |
特种医学 | 519篇 |
外科学 | 3278篇 |
综合类 | 109篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 1598篇 |
眼科学 | 394篇 |
药学 | 1066篇 |
中国医学 | 43篇 |
肿瘤学 | 1356篇 |
出版年
2023年 | 167篇 |
2022年 | 376篇 |
2021年 | 820篇 |
2020年 | 360篇 |
2019年 | 709篇 |
2018年 | 822篇 |
2017年 | 478篇 |
2016年 | 486篇 |
2015年 | 564篇 |
2014年 | 774篇 |
2013年 | 1078篇 |
2012年 | 1763篇 |
2011年 | 1670篇 |
2010年 | 959篇 |
2009年 | 890篇 |
2008年 | 1410篇 |
2007年 | 1453篇 |
2006年 | 1364篇 |
2005年 | 1334篇 |
2004年 | 1078篇 |
2003年 | 1016篇 |
2002年 | 983篇 |
2001年 | 147篇 |
2000年 | 75篇 |
1999年 | 142篇 |
1998年 | 146篇 |
1997年 | 142篇 |
1996年 | 123篇 |
1995年 | 120篇 |
1994年 | 101篇 |
1993年 | 84篇 |
1992年 | 75篇 |
1991年 | 70篇 |
1990年 | 49篇 |
1989年 | 45篇 |
1988年 | 39篇 |
1987年 | 44篇 |
1986年 | 43篇 |
1985年 | 51篇 |
1984年 | 42篇 |
1983年 | 29篇 |
1982年 | 30篇 |
1981年 | 38篇 |
1980年 | 30篇 |
1979年 | 35篇 |
1978年 | 35篇 |
1977年 | 23篇 |
1976年 | 33篇 |
1975年 | 21篇 |
1974年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Although tricyclic antidepressant are especially useful in the treatment of chronic pain conditions, most of the work about its mechanism of action has been made on acute pain tests. The present study was aimed at studying the role played by noradrenergic and opioidergic influences on the antinociceptive activity of subchronically administered clomipramine in the formalin test (a tonic pain model) in rats. Clomipramine produced antinociception after 7 days, administration (2.5 mg/kg/day), an effect equivalent to that obtained by acute morphine (5 mg/kg). The antinociceptive effect of clomipramine was inhibited by the following: nonspecific blocking of alpha1-and alpha2-adrenoceptors by phentolamine, specific blocking of alpha1-adrenoceptors by prazosin; stimulation of alpha2 receptors by clonidine; and blocking of the opioid receptors by naloxone. Blocking the alpha2-receptors with yohimbine did not antagonize the effect of clomipramine. These results suggest that clomipramine produces antinociception in this test, partly via the participation of the endogenous opioid system and partly by further activating or potentiating previously activated noradrenergic pathways which are involved in the control of pain information. 相似文献
32.
Background. Port-wine stains (PWSs) are capillary malformations that usually show progressive stasis of the vascular channels and cause slow hyperplasia of the soft and hard tissues. When these lesions involve the lower lip, macrocheilia may be developed along the time. Vascular-specific lasers are not adequate to correct these three-dimensional tissue deformities, and surgical management becomes necessary, resulting in considerable morbidity and aesthetic disturbances.
Objective. To report a case of macrocheilia secondary to PWS treated by combination of surgery and carbon dioxide laser.
Methods. A 51-year-old man with macrocheilia of the lower lip and severe functional impairment, secondary to long evolution PWS, received treatment with carbon dioxide laser vaporization and minimal surgical correction, resulting in significant improvement of the lower lip hypertrophy, good aesthetic and functional status, and preservation of the muscular function.
Conclusions. Combined carbon dioxide laser and surgery treatment may constitute a valuable alternative in treatment of macrocheilia secondary to PWS because bleeding risk is minimized and improves the preservation of muscular function and aesthetic results in relationship to conventional surgical approaches. 相似文献
Objective. To report a case of macrocheilia secondary to PWS treated by combination of surgery and carbon dioxide laser.
Methods. A 51-year-old man with macrocheilia of the lower lip and severe functional impairment, secondary to long evolution PWS, received treatment with carbon dioxide laser vaporization and minimal surgical correction, resulting in significant improvement of the lower lip hypertrophy, good aesthetic and functional status, and preservation of the muscular function.
Conclusions. Combined carbon dioxide laser and surgery treatment may constitute a valuable alternative in treatment of macrocheilia secondary to PWS because bleeding risk is minimized and improves the preservation of muscular function and aesthetic results in relationship to conventional surgical approaches. 相似文献
33.
Rogelio Leira José Castillo Francisco Martinez José Maria Prieto Manuel Noya 《Cephalalgia : an international journal of headache》1993,13(5):346-348
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
34.
35.
36.
Manuel Castro-Gago Inés Novo Rodriguez Antonio Rodriguez-Núñez José Peña Guitián Santiago Lojo Rocamonde Santiago Rodriguez-Segade 《Child's nervous system》1989,5(6):361-363
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
37.
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
38.
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
39.
Lymphoepithelioma-like carcinoma of the bladder: three cases with clinicopathological and p53 protein expression study 总被引:12,自引:0,他引:12
Izquierdo-García FM García-Díez F Fernández I Pérez-Rosado A Sáez A Suárez-Vilela D Guerreiro-González R Benéitez-Alvarez M 《Virchows Archiv : an international journal of pathology》2004,444(5):420-425
Lymphoepithelioma-like carcinoma of the bladder is an uncommon neoplasm, of which 49 cases have been described in the English literature, none of which has been studied for p53 protein expression. We studied three muscle-infiltrating cases of this tumor using immunohistochemical, in situ hybridization and polymerase chain reaction (PCR) methods. The three cases were positive for epithelial markers and negative for lymphoid antigens in the tumoral syncytial areas. The intensive infiltrate of small cells was negative for epithelial and positive for lymphoid markers. This population was mainly made up of cytotoxic T-lymphocytes, positive for TIA-1. p53 protein was intensely positive in more than 90% of the epithelial component nuclei, being negative in the lymphoid cells. PCR study did not show mutations on p53. Both lymphocytes and epithelium were negative for Epstein–Barr virus markers, such as the latent membrane protein and EBER (Epstein–Barr-encoded RNA). The prognosis was very good after radiotherapy and chemotherapy treatment, preserving the bladder despite the muscle infiltration. The presence of an intense cytotoxic T-lymphocyte population may be related to this good prognosis. Both aspects, p53 protein status and T-lymphoid population, had never been studied before in bladder lymphoepithelioma-like carcinoma. 相似文献
40.
Norbert B Ghyselinck Nadège Vernet Christine Dennefeld Norbert Giese Heinz Nau Pierre Chambon Stéphane Viville Manuel Mark 《Developmental dynamics》2006,235(6):1608-1622
Using Rbp4-null mice as models, we have established for the first time the kinetics of the spermatogenetic alterations during vitamin A deficiency (VAD). Our data demonstrate that the VAD-induced testicular degeneration arises through the normal maturation of germ cells in a context of spermatogonia differentiation arrest. They indicate that retinoic acid (RA) appears dispensable for the transition of premeiotic to meiotic spermatocytes, meiosis, and spermiogenesis. They confirm that RA plays critical roles in controlling spermatogonia differentiation, spermatid adhesion to Sertoli cells, and spermiation, and suggest that the VAD-induced arrest of spermatogonia differentiation results from simultaneous blocks in RA-dependent events mediated by RA receptor gamma (RARgamma) in spermatogonia and by RARalpha in Sertoli cells. They also provide evidence that expression of major RA-metabolizing enzymes is increased in mouse Sertoli cells upon VAD and that vitamin A-deficient A spermatogonia differ from their RA-sufficient counterparts by the expression of the Stra8 gene. 相似文献