首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   143篇
  免费   11篇
  国内免费   1篇
妇产科学   13篇
基础医学   16篇
口腔科学   1篇
临床医学   9篇
内科学   20篇
皮肤病学   3篇
特种医学   1篇
外科学   44篇
综合类   8篇
预防医学   7篇
药学   26篇
中国医学   3篇
肿瘤学   4篇
  2023年   2篇
  2022年   5篇
  2021年   5篇
  2020年   3篇
  2019年   1篇
  2018年   6篇
  2017年   2篇
  2016年   2篇
  2015年   2篇
  2014年   6篇
  2013年   5篇
  2012年   11篇
  2011年   11篇
  2010年   1篇
  2009年   7篇
  2008年   9篇
  2007年   6篇
  2006年   5篇
  2005年   3篇
  2004年   6篇
  2003年   4篇
  2002年   1篇
  2000年   1篇
  1999年   3篇
  1998年   1篇
  1997年   2篇
  1996年   2篇
  1995年   2篇
  1994年   4篇
  1993年   3篇
  1992年   7篇
  1991年   6篇
  1986年   1篇
  1985年   1篇
  1981年   1篇
  1980年   2篇
  1977年   3篇
  1976年   1篇
  1975年   1篇
  1974年   3篇
  1971年   2篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   2篇
排序方式: 共有155条查询结果,搜索用时 15 毫秒
81.
Subungual exostosis is an unusual, benign, osteocartilaginous tumor with a tendency to recurrence. The authors report a retrospective series of 15 cases of subungual exostosis of the big toe. There were nine male and six female patients, with a mean age of 18 years. A history of trauma or repetitive microtrauma was noted in 8 cases. Surgical treatment was performed using the most direct approach. The tumor was completely excised and the ungual apparatus was reconstructed. All patients were monitored without recurrence.  相似文献   
82.
83.
The effects of chronic exposure (2 h daily for 21 days) of 1 kHz square wave-modulated 2450 MHz microwave radiation (non-thermal) on sleep-EEG, open field behavior, and thyroid hormones (T3, T4, and TSH) have been analyzed in an animal model. Results revealed significant changes in these pathophysiological parameters (p < 0.05 or better), except body temperature, grooming behavior, and TSH levels. The sleep-EEG power spectrum data for slow wave sleep (SWS), rapid eye movement (REM) sleep, and awake (AWA) states in two experimental groups of rats (microwave exposed and the control) were tested by an artificial neural network (ANN), containing 60 nodes in input layer, weighted from power spectrum data from 0 to 30 Hz, 18 nodes in hidden layer and an output node. The target output values for this network were determined with another five-layered neural network (with the structure of 6-14-1-14-6). The input and output of this network was assigned with the six confirmed pathophysiological changes. The most important feature for chronic exposure of 2450 MHz microwave exposure and for control subjects was extracted from the third layer single neuron and used as the target value for the three-layered ANN. The network was found effective in recognizing the EEG power spectra with an average of 71.93% for microwave exposure and 93.13% for control subjects, respectively. However, the lower percentage of pattern identification agreement in the microwave-exposed group in comparison to the control group suggest only mild effects of microwave exposure with this experimental setup.  相似文献   
84.
In a series of acute and chronic experiments conducted in young pigs during a 2-year period, we have evolved a quick knotting technique to start and end a suture line and developed a curved 'Endoski' needle to improve needle passage through the tissues. These have been employed in the construction of cholecystojejunal anastomoses using a semi-closed technique with a single layer (deep seromuscular) of continuous polyglactin sutures. In chronic experiments in pigs, patent well healed bilioenteric anastomoses, which conveyed bile satisfactorily after ligation of the common bile duct, distal to the cystic duct, were achieved. A virtual absence of adhesions in these animals was noted.  相似文献   
85.
Abstract: In the 11‐residue long dark‐color‐inducing neurohormone (DCIN = [His7]‐corazonin), of locusts, from residue 2 to residue 11, one amino acid at each time was substituted by d ‐phenylalanine (d ‐Phe). The dark‐color‐inducing effect of these peptides was investigated in comparison with unaltered DCIN by a bioassay based on nymphs of a DCIN‐deficient albino mutant of the migratory locust, Locusta migratoria. Substitution of any single amino acid by d ‐Phe always reduced the activity, but did not abolish it completely. Maximum inactivation was obtained after substitution of Gln4, Ser6, or Trp9. The latter two residues are within the partial sequence ‐Ser‐Xxx‐Gly‐Trp‐ (Xxx = His in the DCIN) that seems to be important for the dark‐color‐inducing activity, as found also in another study (Insect Biochem. Mol. Biol. 32, 2002, 909). Gln4, however, is outside of this partial sequence. Minimal, although still considerable, inactivation occurred after substitution of Gly8, Phe3, or Asn11, despite the fact that Gly8 is within the ‐Ser‐Xxx‐Gly‐Trp‐ partial sequence. In conclusion, no single active core was found, indicating that the whole sequence of the DCIN is necessary to induce maximum darkening effect. No difference was found in the activity of the peptides in which Gly8 was substituted by d ‐Phe or by l ‐Phe. Therefore the ‐Ser‐Xxx‐Gly‐Trp‐ partial sequence does not seem to be stabilized by a type II β‐turn. Nevertheless, existence of another kind of turn that includes this partial sequence is feasible. A single unsuccessful attempt was made to discover an antagonist to the DCIN.  相似文献   
86.
87.
Modulation of interactions between activated GPCRs (G-protein coupled receptors) and the intracellular (IC) signal transducers, heterotrimeric G-proteins, is an attractive, yet essentially unexplored, paradigm for treatment of certain diseases. Regulating downstream signaling for treatment of congenital diseases due to constitutively active GPCRs, as well as tumors where GPCRs are often overexpressed, requires the development of new methodologies. Modeling, experimental data, docking, scoring, and experimental testing (MEDSET) was developed to discover inhibitors that target the IC loops of activated GPCRs. As proof-of-concept, MEDSET developed and utilized a model of the interface between photoactivated rhodopsin (R*) and transducin (Gt), its G-protein. A National Cancer Institute (NCI) compound library was screened to identify compounds that bound at the interface between R* and its G-protein. High-scoring compounds from this virtual screen were obtained and tested experimentally for their ability to stabilize R* and prevent Gt from binding to R*. Several compounds that modulate signal transduction have been identified.  相似文献   
88.
BACKGROUND: Unicondylar femoral fractures are rare. They form a particular entity of the femoral lower extremity fractures. THE PURPOSE of this work was to evaluate the anatomical and functional results of unicondylar femoral fractures on pain, mobility, walking and stability of the knee. METHODS: We reviewed, retrospectively, 28 patients presenting unicondylar femoral fracture. There were 19 men and 9 women, with average age of 54 years (22 - 87 years), victims essentially of domestic accident. The fracture was alone in 65 % of cases. According to Nordin's classification, the fracture was of type I in 3% of cases, type II in 35 % of cases, type III in 20 % of cases and type IV in 42 % of cases. Twenty five patients had a surgical treatment after a median period of 7 days post-accident, 3 patients were treated orthopedically. RESULTS: After 3 years follow up, results were noted according to MEGY's score which takes into account walking, mobility, pain and the stability. Clinically, we noted 26 good and very good results and 2 moderate results. Anatomically, we obtained 75 % of satisfactory reductions. CONCLUSION: Unicondylar femoral fractures remain rare. It is important to recognize them and to make the exact diagnosis of their type. Surgical treatment exposes old subjects to risk of dismantling anatomical osteosynthesis because of osteoporoses.  相似文献   
89.
Two new series of diaminoacridinic derivatives obtained from proflavine and N-(6-amino-3-acridinyl)acetamide were synthesised and assessed for their cytotoxic and antileishmanial activities. Two compounds, N-[6-(acetylamino)-3-acridinyl]acetamide and N-[6-(benzoylamino)-3-acridinyl]benzamide demonstrated highly specific antileishmanial properties against the intracellular amastigote form of the parasite. Structure-activity relationships established that the antiproliferative activity against human cells was greatly enhanced by the presence of a benzoylamino group in 6-mono-substituted acridines, while the presence of two acetylamino or benzoylamino groups in 3,6-di-substituted acridines strongly increased the specificity of the molecules for Leishmania parasite, suggesting that symmetric conformations could preferentially interfere with Leishmania metabolism.  相似文献   
90.
4,4′-Isopropylidine-bis[2-isopropyl]phenol was found to possess antimicrobial activity against gram-positive bacteria and some fungi, whereas it had no effect on gram-negative organisms. The drug has a potent inhibitory action on the synthesis of cell wall mucopeptides of Bacillus subtilis by inhibiting the enzyme d-glutamate ligase, which is responsible for the incorporation of d-glutamic acid into uridine 5′-diphosphate-muramyl-l-alanine. The drug had a weak lytic effect on protoplasts and inhibited protein synthesis, whereas no significant effect on the synthesis of deoxyribonucleic acid and ribonucleic acid was found.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号