全文获取类型
收费全文 | 139700篇 |
免费 | 9861篇 |
国内免费 | 244篇 |
专业分类
耳鼻咽喉 | 1302篇 |
儿科学 | 3899篇 |
妇产科学 | 2900篇 |
基础医学 | 21879篇 |
口腔科学 | 3878篇 |
临床医学 | 11735篇 |
内科学 | 27849篇 |
皮肤病学 | 2394篇 |
神经病学 | 13933篇 |
特种医学 | 5750篇 |
外国民族医学 | 20篇 |
外科学 | 17810篇 |
综合类 | 587篇 |
现状与发展 | 1篇 |
一般理论 | 123篇 |
预防医学 | 15242篇 |
眼科学 | 2247篇 |
药学 | 8391篇 |
中国医学 | 253篇 |
肿瘤学 | 9612篇 |
出版年
2023年 | 579篇 |
2022年 | 984篇 |
2021年 | 2082篇 |
2020年 | 1530篇 |
2019年 | 2220篇 |
2018年 | 2795篇 |
2017年 | 2373篇 |
2016年 | 2619篇 |
2015年 | 2889篇 |
2014年 | 3962篇 |
2013年 | 5190篇 |
2012年 | 7931篇 |
2011年 | 8023篇 |
2010年 | 4212篇 |
2009年 | 4378篇 |
2008年 | 7168篇 |
2007年 | 7380篇 |
2006年 | 7117篇 |
2005年 | 6739篇 |
2004年 | 5817篇 |
2003年 | 5565篇 |
2002年 | 5001篇 |
2001年 | 4921篇 |
2000年 | 4864篇 |
1999年 | 4400篇 |
1998年 | 1783篇 |
1997年 | 1497篇 |
1996年 | 1558篇 |
1995年 | 1258篇 |
1994年 | 1180篇 |
1993年 | 1088篇 |
1992年 | 3019篇 |
1991年 | 2749篇 |
1990年 | 2632篇 |
1989年 | 2474篇 |
1988年 | 2281篇 |
1987年 | 1987篇 |
1986年 | 1888篇 |
1985年 | 1807篇 |
1984年 | 1270篇 |
1983年 | 1107篇 |
1982年 | 594篇 |
1981年 | 524篇 |
1979年 | 963篇 |
1978年 | 576篇 |
1977年 | 508篇 |
1974年 | 511篇 |
1973年 | 506篇 |
1972年 | 499篇 |
1971年 | 463篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
11.
The use of additional epidural sympathetic block during and after microvascular surgery in the lower extremities to prevent vasospasm is generally agreed on. However, a significant fall in the perfusion rate of the transplants was seen after application of bupivacaine (Marcain) via the epidural catheter. This effect has, to our knowledge, not been described before and is probably caused by the sympathectomy effect of this type of analgesia. 相似文献
12.
T F Kruger J P Van der Merwe H J Odendaal F S Stander G M Grobler V A Hulme E L Erasmus K Coetzee M L Windt Y Swart 《Suid-Afrikaanse tydskrif vir geneeskunde》1990,77(12):634-636
The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate. 相似文献
13.
A E van der Merwe F J Mattheyse M Bedford P D van Helden D J Rossouw 《Burns : journal of the International Society for Burn Injuries》1990,16(3):193-197
Cultured keratinocytes were used as allografts on burn wounds in two patients. In both patients successful covering of the wounds was obtained. DNA fingerprinting of the epidermis covering the wounds 21 days later showed that the cultured keratinocytes were replaced by the patients' cells. 相似文献
14.
M. Wensing A. H. Penninks† S. L. Hefle‡ J. H. Akkerdaas§ R. van Ree§ S. J. Koppelman† C. A. F. M. Bruijnzeel-Koomen A. C. Knulst 《Clinical and experimental allergy》2002,32(12):1757-1762
BACKGROUND: The risk for allergic reactions depends on the sensitivity of individuals and the quantities of offending food ingested. The sensitivity varies among allergic individuals, as does the threshold dose of a food allergen capable of inducing an allergic reaction. OBJECTIVE: This study aimed at determining the distribution of minimum provoking doses of hazelnut in a hazelnut-allergic population. METHODS: Thirty-one patients with a history of hazelnut-related allergic symptoms, a positive skin prick test to hazelnut and/or an elevated specific IgE level, were included. Double-blind, placebo-controlled food challenges (DBPCFC) were performed with seven increasing doses of dried hazelnut (1 mg to 1 g hazelnut protein) randomly interspersed with seven placebo doses. RESULTS: Twenty-nine patients had a positive challenge. Itching of the oral cavity and/or lips was the first symptom in all cases. Additional gastrointestinal symptoms were reported in five patients and difficulty in swallowing in one patient. Lip swelling was observed in two patients, followed by generalized urticaria in one of these. Threshold doses for eliciting subjective reactions varied from a dose of 1 mg up to 100 mg hazelnut protein (equivalent to 6.4-640 mg hazelnut meal). Extrapolation of the dose-response curve showed that 50% of our hazelnut-allergic population will suffer from an allergic reaction after ingestion of 6 mg (95% CI, 2-11 mg) of hazelnut protein. Objective symptoms were observed in two patients after 1 and 1,000 mg, respectively. CONCLUSION: DBPCFCs demonstrated threshold doses in half of the hazelnut-allergic patients similar to doses previously described to be hidden in consumer products. This stresses the need for careful labelling and strategies to prevent and detect contamination of food products with hazelnut residues. 相似文献
15.
16.
Up to now two abnormal nephrographic patterns have been described as a result of arterial hypotension as an adverse response to urographic contrast material. We would like to describe a third pattern. 相似文献
17.
18.
The simultaneous determination of cerebrospinal fluid and plasma adenosine deaminase activity as a diagnostic aid in tuberculous meningitis 总被引:1,自引:0,他引:1
P R Donald C Malan A van der Walt J F Schoeman 《Suid-Afrikaanse tydskrif vir geneeskunde》1986,69(8):505-507
The simultaneous determination of cerebrospinal fluid (CSF) and plasma adenosine deaminase (ADA) activity was evaluated as a diagnostic aid in tuberculous meningitis (TBM). CSF and plasma ADA activity were determined in four groups of patients: (i) a 'no meningitis' group of 174 children investigated for possible meningitis, but found to be uninfected; (ii) an aseptic meningitis group of 40 children; (iii) a bacterial meningitis group of 31 children; and (iv) a TBM group of 27 patients (24 children and 3 adults). CSF ADA alone was determined in a further 23 children with aseptic meningitis, 19 with bacterial meningitis and 13 children and 7 adults with TBM. Both the CSF/plasma ADA ratio and the absolute CSF ADA activity were raised in TBM (mean values 0,24 and 12,61 U/I respectively) and bacterial meningitis (mean values 0,59 and 15,43 U/I respectively), but not in the aseptic meningitis group (mean values 0,06 and 2,00 U/I) or the 'no meningitis' group (mean values 0,04 and 1,51 U/I). Both values will distinguish TBM from aseptic meningitis, but do not appear to hold any marked advantages over conventional CSF criteria in the diagnosis of TBM. 相似文献
19.
A Dekker A A Poot J A van Mourik M P Workel T Beugeling A Bantjes J Feijen W G van Aken 《Thrombosis and haemostasis》1991,66(6):715-724
Endothelial cell seeding may improve the patency of synthetic vascular grafts provided that platelet reactivity of nonendothelialized sites is not increased. We have investigated if surface-adsorbed monoclonal antibodies directed against endothelial cell membrane proteins and against extracellular matrix proteins promote the adhesion and proliferation of cultured human endothelial cells, without causing platelet deposition at non-endothelialized sites. Adhesion of endothelial cells onto polyethylene coated with monoclonal antibodies directed against endothelial cell-specific membrane antigens, integrin receptors and glycoprotein CD31 was equal to or higher than adhesion onto fibronectin-coated polyethylene. Endothelial cells did not proliferate on these surface-adsorbed antibodies. However, pre-coating of polyethylene with mixtures of endothelial cell-specific monoclonal antibodies and monoclonal antibodies directed against fibronectin or von Willebrand factor, resulted in relatively high adhesion and optimal proliferation. Platelet reactivity of the polyethylene surface was found to significantly increase after adsorption of fibronectin, endothelial cell-specific monoclonal antibody or its Fc fragments. In contrast, adsorption of F(ab')2 fragments of endothelial cell-specific monoclonal antibody did not promote platelet deposition. Therefore, it is concluded that coating of vascular graft materials with mixtures of F(ab')2 fragments of monoclonal antibodies specifically directed against endothelial cells and against extracellular matrix proteins may be an effective way to both promote the growth of seeded endothelial cells and limit platelet-graft interaction. 相似文献
20.
P G Raijmakers M C Cabezas J A Smal J van Gijn 《Clinical neurology and neurosurgery》1991,93(3):201-204
The efficacy of an instructional videotape about the interpretation of the plantar response was evaluated during a two week neurological clerkship. Experimental groups saw the videotape, control groups did not. All students (n = 65) assessed plantar responses of two to four different patients. Their judgment was compared with that of one senior neurologist. Only the students who had seen the videotape showed a significant improvement in performance on a second test (t-test, t = -2.26, p = 0.031). In addition, these students more frequently took account of the flexion synergy (Fisher exact test, p less than 0.001). Video can be an efficient tool in medical education. 相似文献