全文获取类型
收费全文 | 740篇 |
免费 | 61篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 49篇 |
妇产科学 | 6篇 |
基础医学 | 70篇 |
口腔科学 | 42篇 |
临床医学 | 68篇 |
内科学 | 125篇 |
皮肤病学 | 35篇 |
神经病学 | 15篇 |
特种医学 | 218篇 |
外科学 | 28篇 |
综合类 | 35篇 |
预防医学 | 35篇 |
眼科学 | 4篇 |
药学 | 50篇 |
肿瘤学 | 42篇 |
出版年
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 15篇 |
2013年 | 9篇 |
2012年 | 6篇 |
2011年 | 8篇 |
2010年 | 18篇 |
2009年 | 23篇 |
2008年 | 20篇 |
2007年 | 11篇 |
2006年 | 15篇 |
2005年 | 11篇 |
2004年 | 10篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 13篇 |
1998年 | 42篇 |
1997年 | 45篇 |
1996年 | 42篇 |
1995年 | 36篇 |
1994年 | 23篇 |
1993年 | 31篇 |
1992年 | 23篇 |
1991年 | 18篇 |
1990年 | 13篇 |
1989年 | 25篇 |
1988年 | 28篇 |
1987年 | 44篇 |
1986年 | 26篇 |
1985年 | 16篇 |
1984年 | 8篇 |
1983年 | 12篇 |
1982年 | 14篇 |
1981年 | 20篇 |
1980年 | 17篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 21篇 |
1975年 | 10篇 |
1934年 | 4篇 |
1933年 | 3篇 |
1930年 | 3篇 |
1927年 | 4篇 |
1926年 | 4篇 |
排序方式: 共有823条查询结果,搜索用时 15 毫秒
1.
2.
3.
Ralls PW; Johnson MB; Kanel G; Dobalian DM; Colletti PM; Boswell WD Jr; Radin DR; Halls JM 《Radiology》1986,161(2):451-454
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease. 相似文献
4.
5.
6.
Yoshimitsu Kuroyanagi DR. ENG DR. SCI DR. MED ; Akihiko Shiraishi MD ; Yoshiteru Shirasaki MD ; Nobuaki Nakakita MD ; Yoshiaki Yasutomi MD ; Yasuo Takano MD ; Nobuyuki Shioya MD FACS 《Wound repair and regeneration》1994,2(2):122-129
A bilaminar wound dressing composed of an outer membrane and an inner three-dimensional matrix of a fabric or a sponge may be considered to constitute an ideal structure that promotes wound healing: the outer membrane prevents body fluid loss, controls water evaporation, and protects the wound surface from bacterial invasion, and the inner matrix encourages adherence by tissue growth into the matrix. Using this concept, we developed a biosynthetic wound dressing with a drug delivery capability. This medicated wound dressing is composed of a spongy sheet of a chitosane derivative and collagen mixture that is laminated to an antimicrobial-impregnated polyurethane membrane. In this study, a gentamycin sulfate-impregnated wound dressing was prepared and evaluated. The antimicrobial efficacy of this wound dressing was examined on an agar plate seeded with Pseudomonas aeruginosa. Also, the cytotoxicity of an antimicrobial released from this wound dressing was examined in an in vitro system with cultured skin substitutes. Both in vitro tests have shown that this wound dressing is capable of suppressing bacterial growth and minimizing cellular damage. In addition, in the treatment of wounds inflicted on rats and rabbits, this wound dressing was shown to be efficacious in covering full-thickness and split-thickness skin defects. Finally, the efficacy of this wound dressing was evaluated in a nonrandomized open-label study of 31 clinical cases. In 31 cases treated with this wound dressing, good or excellent wound healing was achieved. 相似文献
7.
DR Foster 《Journal of Medical Imaging and Radiation Oncology》1995,39(4):399-400
The use of self-expanding prostheses in the management of malignant oesophageal strictures has become well established. The majority of benign peptic oesophageal strictures can be successfully managed using endoscopic or fluoroscopically guided balloon oesophageal dilatation combined with long-term drug therapy, particularly using proton pumper inhibitors. Although endoscopic oesophageal dilatation can be performed on an outpatient basis, it requires repeated hospital visits. There is a small risk of oesophageal perforation whilst cardio-respiratory complications may be encountered during the use of intravenous sedation in an elderly population. The use of a self-expanding Strecker stent in a 98 year old woman with a benign oesophageal stricture is described. 相似文献
8.
Pharmacological characterization of a receptor for calcitonin gene-related peptide on rat, L6 myocytes.
下载免费PDF全文
![点击此处可从《British journal of pharmacology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
D. R. Poyner D. P. Andrew D. Brown C. Bose M. R. Hanley 《British journal of pharmacology》1992,105(2):441-447
1 The L6 myocyte cell line expresses high affinity receptors for calcitonin gene-related peptide (CGRP) which are coupled to activation of adenylyl cyclase. The biochemical pharmacology of these receptors has been examined by radioligand binding or adenosine 3':5'-cyclic monophosphate (cyclic AMP) accumulation. 2 In intact cells at 37 degrees C, human and rat alpha- and beta-CGRP all activated adenylyl cyclase with EC50s of about 1.5 nM. A number of CGRP analogues containing up to five amino acid substitutions showed similar potencies. In membrane binding studies at 22 degrees C in 1 mM Mg2+, the above all bound to a single site with IC50s of 0.1-0.4 nM. 3 The fragment CGRP(8-37) acted as a competitive antagonist of CGRP stimulation of adenylyl cyclase with a calculated Kd of 5 nM. The Kd determined in membrane binding assays was lower (0.5 nM). 4 The N-terminal extended human alpha-CGRP analogue Tyro-CGRP activated adenylyl cyclase and inhibited [125I]-iodohistidyl-CGRP binding less potently than human alpha-CGRP (EC50 for cyclase = 12 nM, IC50 for binding = 4 nM). 5 The pharmacological profile of the L6 CGRP receptor suggests that it most closely resembles sites on skeletal muscle, cardiac myocytes and hepatocytes. The L6 cell line should be a stable homogeneous model system in which to study CGRP mechanisms and pharmacology. 相似文献
9.
D R Poyner N J Birdsall C Curtis P Eveleigh E C Hulme E K Pedder M Wheatley 《Molecular pharmacology》1989,36(3):420-429
The muscarinic receptor from the cerebral cortex, heart, and lacrimal gland can be solubilized in the zwitterionic detergent 3-(3-cholamidopropyl)dimethylammonio-2-hydroxy-1-propane sulfonate (CHAPSO) with retention of high affinity [3H]N-methyls-copolamine binding. However, in this detergent there are significant differences in the binding properties of the receptors, compared with those observed in membranes and digitonin solution. Some agents retain a degree of selectivity. In the heart and cortex, agonists can bind with high affinity to a receptor-GTP-binding protein complex. A second, lower affinity, agonist binding state is also present, which resembles a class of sites seen in membranes but not in digitonin solution. The high affinity agonist binding state has been resolved from the lower affinity state on sucrose density gradient centrifugation. Hydrodynamic analysis suggests that the high affinity state is approximately 110,000 Da larger than the lower affinity state. The binding properties of the receptor in CHAPSO can be altered to those seen in digitonin by exchanging detergents after CHAPSO solubilization. 相似文献
10.
In 260 asbestos-exposed individuals evaluated by means of computed tomography (CT), 43 unsuspected pulmonary masses were found in 27 individuals. The masses included fissural pleural plaques (n = 10), dense fibrotic bands (n = 3), round atelectasis (n = 11), carcinomas (n = 3), and other presumed benign masses (n = 16). The most helpful features in the diagnosis of rounded atelectasis with CT were (a) contiguity to areas of diffuse pleural thickening, (b) a lentiform or wedge-shaped outline, (c) evidence of volume loss in the adjacent lung, and (d) a characteristic "comet tail" of vessels and bronchi sweeping into the margins of the mass. Less advanced areas of focal atelectasis had fewer classic features. Intrafissural pleural plaques were readily identified with high-resolution CT. In asbestos-related masses, the demonstration of stability over time is necessary. Careful interpretation of CT and high-resolution CT features and close surveillance can obviate the need for biopsy in the majority of instances. 相似文献