全文获取类型
收费全文 | 18702篇 |
免费 | 1081篇 |
国内免费 | 98篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 554篇 |
妇产科学 | 345篇 |
基础医学 | 2594篇 |
口腔科学 | 313篇 |
临床医学 | 1552篇 |
内科学 | 4718篇 |
皮肤病学 | 302篇 |
神经病学 | 2028篇 |
特种医学 | 815篇 |
外科学 | 2124篇 |
综合类 | 43篇 |
一般理论 | 2篇 |
预防医学 | 948篇 |
眼科学 | 175篇 |
药学 | 1370篇 |
中国医学 | 29篇 |
肿瘤学 | 1856篇 |
出版年
2023年 | 120篇 |
2022年 | 272篇 |
2021年 | 509篇 |
2020年 | 280篇 |
2019年 | 375篇 |
2018年 | 476篇 |
2017年 | 350篇 |
2016年 | 409篇 |
2015年 | 476篇 |
2014年 | 633篇 |
2013年 | 783篇 |
2012年 | 1199篇 |
2011年 | 1301篇 |
2010年 | 676篇 |
2009年 | 615篇 |
2008年 | 1055篇 |
2007年 | 1100篇 |
2006年 | 971篇 |
2005年 | 944篇 |
2004年 | 842篇 |
2003年 | 817篇 |
2002年 | 727篇 |
2001年 | 429篇 |
2000年 | 424篇 |
1999年 | 436篇 |
1998年 | 171篇 |
1997年 | 130篇 |
1996年 | 131篇 |
1995年 | 99篇 |
1994年 | 100篇 |
1993年 | 91篇 |
1992年 | 280篇 |
1991年 | 269篇 |
1990年 | 270篇 |
1989年 | 252篇 |
1988年 | 192篇 |
1987年 | 163篇 |
1986年 | 184篇 |
1985年 | 208篇 |
1984年 | 120篇 |
1983年 | 98篇 |
1982年 | 68篇 |
1981年 | 47篇 |
1979年 | 108篇 |
1977年 | 56篇 |
1976年 | 53篇 |
1975年 | 53篇 |
1974年 | 47篇 |
1973年 | 56篇 |
1971年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Calcagni A Ciattini PG Di Stefano A Duprè S Luisi G Pinnen F Rossi D Spirito A 《Il Farmaco; edizione pratica》1999,54(10):673-677
This paper reports the synthesis of tauryl dipeptides related to carnosine. In particular H-Tau-His-OH (5), H-Tau-His(pi-Me)-OH (6) and H-Tau-His(tau-Me)-OH (9) are described. The enzyme carnosinase has been isolated from pig kidney and after purification has been used to test the stability and the inhibitory activity of the three new analogues. H-Tau-His-OH (5) and H-Tau-His(tau-Me)-OH (9) were found to possess weak inhibitory properties towards carnosinase, while H-Tau-His(pi-Me)-OH (6) proved to be devoid of any significant activity. All the three sulfonamido pseudopeptides 5, 6 and 9 show stability to carnosinase activity. 相似文献
102.
Interethnic and interindividual variabilities of platelet sulfotransferases activity in Italians and Finns 总被引:1,自引:0,他引:1
Brittelli A De Santi C Raunio H Pelkonen O Rossi G Pacifici GM 《European journal of clinical pharmacology》1999,55(9):691-695
Objective: The aim of this investigation was to see whether there was interethnic variability in the platelet activities of catechol-
and phenol sulfotransferases in Italians and Finns.
Methods: The activities of catechol- and phenol sulfotransferases were measured in platelets obtained from 103 Italian and 74 Finnish
individuals. Blood donors were obtained from healthy volunteers free from drugs and without apparent disease. The activities
of catechol- and phenol sulfotransferases were measured with 60 μM dopamine and 4 μM 4-nitrophenol as substrates, respectively
Results: The activity of catechol sulfotransferase was not gender dependent and the median estimates (pmol/min/mg) were 9.10 in Italians
and 6.37 in Finns (P = 0.0018). The activity of phenol sulfotransferase activity was gender dependent in Finns but not in Italians. The median
estimates (pmol/min/mg) were 3.81 in Finnish men and 1.18 in Finnish women (P = 0.0007). In Italian men and women, the median estimates (pmol/min/mg) of phenol sulfotransferase activity were 1.25 and
1.24, respectively (NS).
Conclusion: This study shows that platelet catechol sulfotransferase activity is greater in Italians than Finns and that the activity
of phenol sulfotransferase is gender regulated in Finns but not in Italians. Thus, interethnic differences exist in platelet
sulfotransferases between Italians and Finns.
Received: 16 April 1999 / Accepted in revised form: 20 August 1999 相似文献
103.
Antibiotic combination therapy in patients with chronic, treatment-resistant pouchitis 总被引:9,自引:0,他引:9
P. Gionchetti F. Rizzello A. Venturi F. Ugolini M. Rossi P. Brigidi R. Johansson A. Ferrieri G. Poggioli & M. Campieri 《Alimentary pharmacology & therapeutics》1999,13(6):713-718
BACKGROUND: Pouchitis is the major long-term complication after ileal pouch-anal anastomosis for ulcerative colitis. About 15% of patients have a chronic, treatment-resistant disease. AIMS: To evaluate the efficacy of an antibiotic combination for chronic active, treatment-resistant pouchitis. PATIENTS AND METHODS: Eighteen patients were treated orally with rifaximin 1 g b.d. + ciprofloxacin 500 mg b.d. for 15 days. Symptoms assessment, endoscopic and histological evaluations were performed at screening and after 15 days using the Pouchitis Disease Activity Index (PDAI). Improvement was defined as a decrease of at least 3 points in PDAI score, and remission as a PDAI score of 0. Systemic absorption of rifaximin was determined by high performance liquid chromatography. Faecal samples were collected before and after antibiotic treatment for stool culture. RESULTS: Sixteen out of 18 patients (88.8%) either improved (n=10) or went into remission (n=6); the median PDAI scores before and after therapy were 11 (range 9-17) and 4 (range 0-16), respectively (P < 0.002). No side-effects were reported. Rifaximin plasma levels and urinary excretion were negligible, confirming its mainly topical activity. A significant decrease in total anaerobes and aerobes, enterococci, lactobacilli, bifidobacteria and bacteroides in faecal samples was observed, while the reduction in number of coliforms and Clostridium perfringens did not reach a statistical significance. CONCLUSIONS: A combination of rifaximin and ciprofloxacin was effective in patients with active chronic, treatment-resistant pouchitis, suggesting the need, in these patients, for treatment using antibiotic agents with wide antibacterial spectrum of activity. 相似文献
104.
Maria A. Annunziata Ph.D. Carlo Rossi M.D. Renato Talamini Sc.D. Salvatore Tumolo M.D. Silvio Monfardini M.D. 《Supportive care in cancer》1996,4(5):334-340
The aim of this study was to determine the influence of socio-demographic and professional factors on physicians' attitudes to the terminally ill. Between May 1992 and May 1993, a survey was conducted in the province of Pordenone (north-east, Italy) in order to analyse a number of specific issues, such as emotional involvement, the need for aggressive treatments and the communication of diagnosis and prognosis. After obtaining a list of board-certified physicians from the Medical Association office in Pordenone, a modification of the cancer questionnaire of Haley and Blanchard (QSPT) was mailed to 916 doctors. Of these, 605 (60%; 487 male, 118 female; mean age 41 ± 11 SD) returned the completed questionnaire. Within the group of responders, we identified three main subgroups, according to their type of activity: general practitioners (175, 29%), hospital doctors (235, 39%) and other doctors (195, 32%). In age, sex and activity, the only significant difference between responders and non-responders was age (mean age 41 and 43 years respeetively). Most of the responders (77%) stated that they were able to deal with the terminally ill patient and his/her needs; 44%, however, admitted that patients' anxiety is sometimes unbearable. For the vast majority of the doctors polled (91%), providing a comfortable environment for an incurable patient was more important than pursuing aggressive treatment, but only 44% were convinced of the uselessness of aggressive care. To the question on whether to disclose information about imminent death to allow patients to prepare spiritually, 37% answered No, 38% Yes, and 25% were uncertain. Almost all responders (95%), however, believed in the beneficial effect of hope on the terminally ill. Ourresults suggest that doctors' professional and, most of all, sociodemographic and cultural factors determine the relationship with the patient on both the emotional and the clinical decision-making levels. 相似文献
105.
F. F. Cruz-Sánchez A. Moral M. L. Rossi L. Quintó C. Castejón E. Tolosa J. de Belleroche 《Journal of neural transmission (Vienna, Austria : 1996)》1996,103(11):1317-1329
Summary Aged-related spinal cord changes such as neuronal loss have been related to the degree of clinical severity of amyotrophic lateral sclerosis (ALS); morphological data on synapses are, however, wanting. Variations in synaptophysin (Sph) expression in aging and ALS were thus studied at the level of lower motor neurons in 40 controls with non-neurological diseases and 11 cases of ALS. Control sections of formalin fixed paraffin embedded cervical (C7/8), thoracic (T10) and lumbar spinal cord (L5) and C6, C7, C8 and L5 of ALS cases were stained with haematoxylin and eosin, luxol fast blue (LFB), and immunostained with a mouse monoclonal antibody against Sph. The neuropil of the anterior horn (AH) in all control cases demonstrated Sph positivity. A dot-like pattern of positivity of presynaptic terminals on soma of motor neurons and fine immunoreactivity along neuronal processes were observed. A significant reduction of Sph immunostaining was observed in the neuropil with increasing age and 3 different somatic patterns were seen: a-well preserved Sph reactivity around the soma and the proximal dendrites of histologically normal neurons; b-few chromatolytic neurons showing large numbers of dot-like presynaptic terminals around the cell body and in a fused pattern; c-intense, diffuse, and homogeneous reactivity of some neurons. Attenuation of Sph reactivity in the AH neuropil, to its complete loss, was observed in all ALS cases. In addition to patterns a-c, two additional microscopic findings were noted in ALS: d-chromatolytic neurons showing complete absence of Sph reactivity; e-absence of Sph reactivity around the soma and the proximal dendrites of histologically normal surviving neurons.Our findings demonstrate that there is a decrease in Sph immunostaining with aging, thus suggesting an alteration in dendritic networks of the AH with aging. Changes in the pattern of Sph immunoreactivity in cell bodies may represent synaptic plasticity and/or degeneration. Reinnervation may also be a possible mechanism as a response to neuronal loss in oldest control cases. Sph reactivity results may thus lend support to the presence of superimposed aging components in ALS cases which may give an insight into explaining the increasing severity of the disease which is encountered with advancing age. 相似文献
106.
M. D'Amico L. Berrino A. Pizzirusso V. de Novellis F. Rossi 《Naunyn-Schmiedeberg's archives of pharmacology》1996,353(3):302-305
The microinjection of l-glutamate (1–6 nmol/rat) and N-methyl-d-aspartate (NMDA 1–10 nmol/rat), ionotropic glutamate receptor (iGluR) agonists, into the nucleus raphe obscurus caused a concentration-dependent increase of arterial blood pressure. In contrast, (±)-1-aminocyclopentane-trans-1, 3-dicarboxylic acid (t-ACPD, 14–42 nmol/rat), a metabotropic glutamate receptor (mGluRs) agonist, caused a concentration-dependent decrease in blood pressure. Pretreatment with D, L-2-amino-phosphono valeric acid (2-APV, 5 nmol/rat) a selective NMDA iGluR antagonist, and (+)-5-methyl-10, 11-dihydro-5H-dibenzo[a, b] cyclohepten-5,10-imine hydrogen maleate (MK801, 0.9 nmol/rat), a noncompetitive NMDA iGluR antagonist, blocked both the glutamate and NMDA pressor responses, while pretreatment with (+)--methyl-4-carboxyphenylglycine (MCPG, 0.05 nmol/rat), a mGluR1 antagonist, increased the glutamate-induced pressor effects and blocked the fall in blood pressure induced by t-ACPD. 6-Cyano-7-nitroquinoxaline-2,3dione-(CNQX, 0.4 nmol/rat) a non-NMDA iGluR antagonist, did not affected the glutamate-induced hypertension. These observations indicate opposing roles for ionotropic and metabotropic receptors in the glutamate-induced blood pressure changes elicited from the nucleus raphe obscurus. Moreover, we suggest that the glutamate-induced hypertension may be due to the activation of NMDA ionotropic receptor subtypes and the metabotropic receptors may influence this activaction through a reduction of excitability at level of synapses. 相似文献
107.
Claudio Pintus Carlo Manzoni Simona Nappo Luigi Perrelli 《Pediatric surgery international》1993,8(2):109-112
In a review of 15 pediatric patients who had ingested caustic substances, the authors describe the diagnostic and therapeutic procedures to be followed as well as the complications that may occur with their use. The cases reported include 1 esophageal rupture caused by balloon dilatation and 1 recurrent stenosis treated with a silastic tutor. 相似文献
108.
C. M. Pacella Z. Rossi G. Bizzarri E. Papini V. Marinozzi D. Paliotta P. Castaldo V. Ziparo F. Garosi M. Cinti F. Muzzi 《European radiology》1993,3(1):26-32
The present report evaluates the efficacy and safety of percutaneous interstitial laser tissue ablation of the liver in nine New Zealand rabbits. A Nd: YAG laser was coupled to a quartz fibreoptic guide (600 m) with a flat tip. The fibre and a thermocouple were placed in the lumen of two Chiba needles (18G) and these were inserted into the liver 10 mm apart under ultrasound guidance. The laser was fired for 5 min at 1, 3 and 5 W power, respectively, in three groups of rabbits. There were no acute complications and all the rabbits except one survived until the established time of sacrifice. The procedure induced a cavity surrounded by a zone (about 10 mm) of coagulative necrosis. After 2 weeks a strong peripheral inflammatory response was evident and after 4 weeks a capsule of connective tissue enclosed the lesions. Our study seems to offer a safe and rapid technique producing a guaranteed kill radius for the treatment of small hepatic neoplasms.
Correspondence to: C. M. Pacella 相似文献
109.
M S Chandra M R Patel D E Laughlin N P Rossi 《The Journal of thoracic and cardiovascular surgery》1978,75(5):765-768
"False inhibition" of a demand pacemaker usually occurs with a microfracture of the lead system resulting in a galvanic potential at the site of the fracture or with sensing of myopotential with exercise. An increase in the slope of the leading half edge of the pulse contour is generally considered diagnostic of lead fracture. We report the case of a patient in whom "false inhibition" at rest and an increase in the slope of the leading half edge of the pulse contour were caused by leakage of fluid into the pacemaker lead socket. 相似文献
110.