全文获取类型
收费全文 | 5385篇 |
免费 | 322篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 137篇 |
妇产科学 | 72篇 |
基础医学 | 794篇 |
口腔科学 | 344篇 |
临床医学 | 460篇 |
内科学 | 1116篇 |
皮肤病学 | 130篇 |
神经病学 | 459篇 |
特种医学 | 214篇 |
外科学 | 615篇 |
综合类 | 25篇 |
一般理论 | 1篇 |
预防医学 | 565篇 |
眼科学 | 58篇 |
药学 | 447篇 |
中国医学 | 32篇 |
肿瘤学 | 193篇 |
出版年
2023年 | 51篇 |
2022年 | 126篇 |
2021年 | 164篇 |
2020年 | 126篇 |
2019年 | 132篇 |
2018年 | 185篇 |
2017年 | 145篇 |
2016年 | 151篇 |
2015年 | 182篇 |
2014年 | 234篇 |
2013年 | 312篇 |
2012年 | 431篇 |
2011年 | 446篇 |
2010年 | 232篇 |
2009年 | 229篇 |
2008年 | 336篇 |
2007年 | 310篇 |
2006年 | 280篇 |
2005年 | 219篇 |
2004年 | 162篇 |
2003年 | 161篇 |
2002年 | 158篇 |
2001年 | 121篇 |
2000年 | 106篇 |
1999年 | 82篇 |
1998年 | 50篇 |
1997年 | 52篇 |
1996年 | 38篇 |
1995年 | 46篇 |
1994年 | 37篇 |
1993年 | 46篇 |
1992年 | 26篇 |
1991年 | 21篇 |
1990年 | 33篇 |
1989年 | 25篇 |
1988年 | 23篇 |
1987年 | 24篇 |
1986年 | 27篇 |
1985年 | 19篇 |
1984年 | 10篇 |
1982年 | 14篇 |
1981年 | 17篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 17篇 |
1975年 | 8篇 |
1969年 | 20篇 |
1967年 | 8篇 |
排序方式: 共有5727条查询结果,搜索用时 15 毫秒
41.
Jorge MP Madjarof C Gois Ruiz AL Fernandes AT Ferreira Rodrigues RA de Oliveira Sousa IM Foglio MA de Carvalho JE 《Journal of ethnopharmacology》2008,118(3):361-366
ETHNOPHARMACOLOGICAL RELEVANCE: Arrabidaea chica Verlot. (Bignoniaceae), popularly known as Crajiru, has been traditionally used as wound healing agent. AIM OF THE STUDY: Investigate in vitro and in vivo healing properties of Arrabidaea chica leaves extract (AC). MATERIALS AND METHODS: AC was evaluated in vitro in fibroblast growth stimulation (0.25-250 microg/mL) and collagen production stimulation (250 microg/mL) assays. Allantoin (0.25-250 microg/mL) and vitamin C (25 microg/mL) were used as controls respectively. DPPH and Folin-Ciocalteau assays were used for antioxidant evaluation, using trolox (0.25-250 microg/mL) as reference antioxidant. To study wound healing properties in rats, AC (100mg/mL, 200 microL/wound/day) was topically administered during 10 days and wound area was evaluated every day. Allantoin (100mg/mL, 200 microL/wound/day) was used as standard drug. After treatment, wound sites were removed for histopathological analysis and total collagen determination. RESULTS: AC stimulated fibroblast growth in a concentration dependent way (EC50=30 microg/mL), increased in vitro collagen production and demonstrated moderate antioxidant capacity. In vivo, AC reduced wound size in 96%, whereas saline group showed only 36% wound healing. CONCLUSION: AC efficiency seems to involve fibroblast growing stimulus and collagen synthesis both in vitro and in vivo, beyond moderate scavenging activity, corroborating Crajiru folk use. 相似文献
42.
Paulo A Martins S Branco P Dias T Borges C Rodrigues AI Costa Mdo C Teixeira A Mota-Filipe H 《Phytotherapy research : PTR》2008,22(4):539-543
The effect of an aqueous extract of Pterospartum tridentatum on the blood glucose levels of normal Wistar rats was investigated in a situation of oral glucose challenge. The extract at 300 mg/kg showed an antihyperglycaemic effect in the first 30 min after glucose challenge but then the blood glucose levels rose above those of the control group, indicating the presence of compounds with different effects on glucose tolerance. Nine compounds of isoflavone and flavonol skeletons were identified in the extract by HPLC-ESI-MS(n), four of them being identified for the first time in this species. The isoflavone sissotrin and the flavonol derivative, isoquercitrin, were selected for the oral glucose tolerance test. Isoquercitrin (100 mg/kg) showed time-dependent antihyperglycaemic activity by delaying the post-oral glucose load glycaemic peak at 30 min, as did the sodium-dependent glucose transporter inhibitor phloridzin (100 mg/kg). In contrast, sissotrin (100 mg/kg) showed an opposite effect, impairing glucose tolerance. In conclusion, these preliminary results indicate that the effect of the extract on blood glucose may be either antihyperglycaemic or hyperglycaemic. Additionally, as far as is known, these are the first in vivo results on the acute antihyperglycaemic potential of isoquercitrin. 相似文献
43.
Cabrita S Rodrigues H Abreu R Martins M Teixeira L Marques C Mota F de Oliveira CF 《European journal of gynaecological oncology》2008,29(2):135-137
PURPOSE OF INVESTIGATION: Magnetic resonance imaging (MRI) has emerged as an important imaging modality in the evaluation of the extension of endometrial carcinoma which is essential in planning treatment and predicting prognosis. This study aimed to assess the value of MRI in the preoperative staging of endometrial carcinoma. METHODS: We included in this study 162 patients with a histological diagnosis of endometrial carcinoma who underwent MRI pelvic imaging and surgical staging. MRI images were compared with pathological findings to measure MRI's sensitivity, specificity, positive and negative predictive values and diagnostic accuracy in what concerns myometrial, cervical and lymph node invasion. RESULTS: MRI differentiation of deep myometrial invasion from superficial disease agreed with pathological findings in 77% of cases, with a sensitivity of 83%, a specificity of 72% and a diagnostic accuracy of 77%. Concerning cervical invasion, MRI had a sensitivity, specificity and diagnostic accuracy of 42%, 92%, 81% respectively. In assessing lymph node invasion, MRI presented a sensitivity of just 17%, a specificity of 99% and a diagnostic accuracy of 89%. CONCLUSION: Our study confirmed the high accuracy of MRI imaging in assessing myometrial and cervical invasion in endometrial carcinoma. When evaluating lymph node invasion, micrometastases are responsible for the low sensitivy of MRI. 相似文献
44.
Background Hereditary pancreatitis is an important cause of chronic pancreatitis, which may result in endocrine and exocrine failure.
This may necessitate simultaneous pancreas and kidney transplant (SPK). Bladder drainage of the exocrine secretions may cause
problems.
Aim To report one such case and its surgical correction.
Methods A 20-year-old male with insulin-dependent diabetes mellitus secondary to idiopathic chronic pancreatitis had a SPK with bladder
drainage. Urological and metabolic complications secondary to the drainage of pancreatic secretions, rich in proteolytic enzymes
required convertion from bladder to enteric drainage.
Results He was able to discontinue his pancreatic enzyme supplements, ceased to have steatorrhoea and gained weight. He was referred
to the €pean Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer (€PAC), hereditary pancreatitis was confirmed
by genetic analysis.
Conclusion Enteric-drained pancreas transplantation is a successful treatment for exocrine as well as endocrine pancreatic failure and
should be considered as a treatment option in patients with chronic pancreatitis. 相似文献
45.
46.
47.
48.
Enio R Vasques Estela RR Figueira Joel A Rocha-Filho Cinthia Lanchotte Jorge LS Ximenes Helena B Nader Ivarne LS Tersariol Marcelo A Lima Tiago Rodrigues José EM Cunha Eleazar Chaib Luiz AC D'Albuquerque Flávio HF Galv?o 《Hepatobiliary & pancreatic diseases international : HBPD INT》2022,21(2):190-192
<正>To the Editor:Ischemia-reperfusion injury following surgery and transplantation can lead to irreversible multiorgan failure.Intracellular calcium overload is associated to cellular death during ischemiareperfusion.A recently discovered heparin fragment (HF),trisulfated disaccharide (TD),that acts on sodium-calcium exchanger(NCX) decreasing intracellular Ca2+,showed effectiveness on protecting hepatocytes from ischemia-reperfusion injury [1], 相似文献
49.
Rena C. Moon Vincent Kirkpatrick Lori Gaskins Andre F. Teixeira Muhammad A. Jawad 《Surgery for obesity and related diseases》2019,15(2):245-252
Background
Biliopancreatic diversion with duodenal switch (DS) is known to be superior in weight loss to other bariatric procedures, but with the disadvantage of increased complication rates. Single-anastomosis duodenal-ileal bypass (SADI-S) is reported to have similar weight loss with lower complication rates compared with traditional DS.Objectives
The aim of this study was to compare weight loss and complication rate between SADI-S and double-anastomosis DS at a single institution.Setting
Academic hospital, United States.Methods
A retrospective chart review was performed on 185 patients who underwent laparoscopic or robot-assisted laparoscopic DS between March 1, 2015 and December 10, 2017. A total of 111 patients had SADI-S, and 74 patients underwent double-anastomosis DS.Results
Baseline patient characteristics were comparable between the 2 groups. The mean preoperative body mass index was 56.3 kg/m2 and 54.4 kg/m2 in SADI-S and double-anastomosis DS patients, respectively. Thirteen (11.7%) and 4 (5.4%) patients were readmitted within 30 days after SADI-S and double-anastomosis DS, respectively (P?=?.16). Percentage of total weight loss was 22.0%, 38.5%, and 44.2% in the SADI-S group and 20.2%, 38.0%, and 48.4% in the double-anastomosis DS group at 6, 12, and 24 months, respectively. The majority of patients had vitamin A and E levels in the normal range. However, 40% to 60% of the patients had low levels of vitamin D after the procedure.Conclusions
SADI-S and double-anastomosis DS are comparable in terms of weight loss and complication rate. However, close nutritional follow-up is warranted for both procedures. 相似文献50.
Michael Nazarkovsky Albina Mikhraliieva Carlos A. Achete Luiz Anastacio Alves Joyce Araujo Brulio S. Archanjo Jos Júnior Frana de Barros Liana Monteiro da Fonseca Cardoso Jos Nelson S. S. Couceiro Fernanda Davi Marques Bruno S. Oliveira Rafael Nascimento Dias de Souza Ayla Josma Teixeira Thiago L. Vasconcelos Vladimir Zaitsev 《RSC advances》2022,12(23):14342
Rational synthesis and simple methodology for the purification of large (35–45 nm in lateral size) and flat (1.0–1.5 nm of height) nitrogen-doped graphene oxide quantum dots (GOQDs) are presented. The methodology allows robust metal-free and acid-free preparation of N-GOQDs with a yield of about 100% and includes hydrothermal treatment of graphene oxide with hydrogen peroxide and ammonia. It was demonstrated that macroscopic impurities can be separated from N-GOQD suspension by their coagulation with 0.9% NaCl solution. Redispersible in water and saline solutions, particles of N-GOQDs were characterized using tip-enhanced Raman spectroscopy (TERS), photoluminescent, XPS, and UV-VIS spectroscopies. The size and morphology of N-GOQDs were studied by dynamic light scattering, AFM, SEM, and TEM. The procedure proposed allows nitrogen-doped GOQDs to be obtained, having 60–51% of carbon, 34–45% of oxygen, and up to 7.2% of nitrogen. The N-GOQD particles obtained in two hours of synthesis contain only pyrrolic defects of the graphene core. The fraction of pyridine moieties grows with the time of synthesis, while the fraction of quaternary nitrogen declines. Application of TERS allows demonstration that the N-GOQDs consist of a graphene core with an average crystallite size of 9 nm and an average distance between nearest defects smaller than 3 nm. The cytotoxicity tests reveal high viability of the monkey epithelial kidney cells Vero in the presence of N-GOQDs in a concentration below 60 mg L−1. The N-GOQDs demonstrate green luminescence with an emission maximum at 505 nm and sedimentation stability in the cell culture medium.This paper reveals the methodology for robust preparation of purified nitrogen-doped graphene oxide quantum dots with non-cytotoxic activity against monkey epithelial kidney cells (Vero ATCC® CCL-81™). 相似文献