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   5912篇
  免费   424篇
  国内免费   32篇
耳鼻咽喉   27篇
儿科学   148篇
妇产科学   122篇
基础医学   1221篇
口腔科学   139篇
临床医学   487篇
内科学   1275篇
皮肤病学   94篇
神经病学   503篇
特种医学   275篇
外国民族医学   1篇
外科学   741篇
综合类   49篇
一般理论   3篇
预防医学   271篇
眼科学   114篇
药学   442篇
中国医学   4篇
肿瘤学   452篇
  2021年   82篇
  2020年   56篇
  2019年   66篇
  2018年   77篇
  2017年   69篇
  2016年   70篇
  2015年   104篇
  2014年   137篇
  2013年   191篇
  2012年   250篇
  2011年   256篇
  2010年   158篇
  2009年   147篇
  2008年   225篇
  2007年   230篇
  2006年   241篇
  2005年   218篇
  2004年   188篇
  2003年   213篇
  2002年   203篇
  2001年   158篇
  2000年   190篇
  1999年   177篇
  1998年   79篇
  1997年   68篇
  1996年   57篇
  1995年   49篇
  1994年   57篇
  1992年   115篇
  1991年   103篇
  1990年   129篇
  1989年   113篇
  1988年   107篇
  1987年   97篇
  1986年   111篇
  1985年   119篇
  1984年   60篇
  1983年   47篇
  1981年   49篇
  1979年   75篇
  1978年   57篇
  1977年   48篇
  1975年   65篇
  1973年   55篇
  1972年   54篇
  1971年   52篇
  1970年   54篇
  1969年   64篇
  1968年   52篇
  1966年   48篇
排序方式: 共有6368条查询结果,搜索用时 468 毫秒
81.
Goncharov I  Weiner L  Vogel Z 《Neuroscience》2005,134(2):567-574
(-)Delta9-tetrahydrocannabinol is a scavenger of free radicals. However, the activation of the CB1 receptor in cultured C6 glioma cells by (-)delta9-tetrahydrocannabinol in the presence of reagents generating reactive oxygen species leads to amplification of the cellular damage from oxidative stress. This was evident by increased loss of cell wall integrity, impaired mitochondrial function and reduction of glucose uptake. In addition, (-)delta9-tetrahydrocannabinol treatment was also found to be deleterious to the cells under conditions of glucose starvation. Free radicals have been implicated in various conditions leading to cell death and, as a routine, the Fenton reaction is utilized for modeling reactive oxygen species production. Our study was performed using a cell permeating Fe(III) chelating quinone that provides more physiological conditions for mimicking the naturally occurring oxidative stress within the cell and thus serves as a better model for natural reactive oxygen species formation.  相似文献   
82.
Mimotope and anti-idiotypic vaccines to induce an anti-IgE response   总被引:1,自引:0,他引:1  
We have defined epitopes on human IgE by screening different phage display random peptide libraries with a monoclonal anti-IgE antibody termed BSW17. The selected mimotopes and epitopes within the Cepsilon3 and Cepsilon4 region of IgE induced antibodies that were nonanaphylactogenic and had biological activity similar to BSW17. The chemically synthesized and KLH-coupled IgE epitopes or mimotopes were used to induce an anti-IgE response in rhesus monkeys. The immunized rhesus monkeys were subsequently protected in a PCA test when sensitized with human IgE and triggered with the corresponding allergen. Furthermore, using the same monoclonal anti-IgE antibody, we also generated an anti-idiotypic antibody that showed sequence homology with the IgE epitope in the Cepsilon3 domain. This anti-idiotypic antibody as well as the mimotopes were then used in a mouse model to induce orally an anti-IgE immune response. For this purpose mice were fed by intragastric gavages with bacteriophages displaying the small IgE-homologous structures. Orally immunized mice produced serum anti-IgE antibodies that were inhibited by BSW17 suggesting that it may be possible to induce a systemic anti-IgE response orally.  相似文献   
83.
84.
85.
A case with 46, XX, del (11) (q21)   总被引:2,自引:0,他引:2  
The cytogenetic analysis of a child with unspecific dysplastic signs revealed the karyotype: 46, XX, del(11) (q21). Two hypotheses could explain the mild phenotypical expression of this deletion:
1) The material of the deficient part of chromosome 11 is genetically inert or redundant (which seems unlikely);
2) "Gene-dosis-compensation" occurs for the loss of genes on the deficient part of chromosome 11.  相似文献   
86.
Poly(epichlorohydrin) and poly(epichlorohydrin-co-ethylene oxide) were modified by reaction with potassium thiocyanate (KSCN), tetrabutylammonium p-toluenesulfinate (NBu4SO2C7H7) and tetrabutylammonium benzenesulfinate (NBu4SO2C6H5). Though the substitution of chlorine in the polymers with these nucleophilic reagents in most cases is accompanied by side reactions, appropriate reaction conditions allow degrees of substitution higher than 90% to be obtained. The glass transition temperature (Tg) of the thiocyanate-modified homo- and copolymer exhibits only a small increase with increasing degree of substitution. While the Tg of the original homo- and copolymer is observed at ?20°C and ?38°C, respectively, the glass transition of the highly substituted homopolymer occurs at ?12°C and for the copolymer at ?31°C. On the other hand, the thiocyanate-modified polymers show a remarkably higher decomposition temperature of about 250°C as compared with that of the unmodified polymers (160–180°C). In addition, the solubility is markedly influenced by the substitution. While the original homo- and copolymers are soluble in, e.g., benzene and toluene, the highly modified products are only soluble in polar solvents such as THF, acetone, DMSO and diglyme. Introducing sulfonyl groups, the resulting polymers exhibit a glass transition temperature increased to a greater extent. For the homopolymer with the highest degree of substitution (98,3%), a Tg of 73°C is observed. Concerning the decomposition temperature, a drastical increase up to 370°C occurs. Finally the influence of phase transfer catalysts on the described reactions was investigated.  相似文献   
87.
This paper describes the development of a murine bank of monoclonal antibodies against Bordetella pertussis toxin, filamentous hemagglutinin (FHA), pili, lipopolysaccharide (LPS), or outer membrane proteins (OMPs). Subunits S1, S2, S3 of pertussis toxin (PT) bound immunoglobulins and glycoproteins such as fetuin and haptoglobin in an unspecific manner. The specificity of monoclonal antibodies towards subunits S1, S2, S3 or S4 of PT could be demonstrated by using purified immunoglobulins or their Fab2 fragments. A set of FHA-specific monoclonal antibodies could be differentiated on the basis of their binding to the various breakdown products present in FHA preparations. Pili-specific monoclonal antibodies reacted with either native pili or denatured pilin, and both demonstrated serotype specificity. Monoclonal antibodies to Bordetella pertussis OMPs were directed to either the virulent phase-regulated trypsin-sensitive, detergent-extractable OMPs 92 kDa, 32 kDa, and 30 kDa or the non-virulent phase-expressed, not-trypsin sensitive OMPs 38 kDa, 33kDa, and 18 kDa.  相似文献   
88.
"Effort" thrombosis is a unique form of subclavian and axillary vein thrombosis because it is the result of an unusual variant of the thoracic outlet syndrome. Another cause of subclavian vein thrombosis is local compression from trauma, tumor, or development anomalies; a third is intimal damage from indwelling central venous catheters. This is a case report of "effort" thrombosis of the subclavian vein in a competitive swimmer. A recently developed technique of local infusion of low-dose streptokinase therapy is used for clot lysis. Early diagnosis is essential for effective thrombus dissolution with streptokinase. The rationale, risk, and method of streptokinase administration are discussed. Since "effort" thrombosis is secondary to thoracic outlet syndrome (TOS), decompression of the thoracic outlet by removal of the first rib after clot lysis is recommended.  相似文献   
89.
90.
Zusammenfassung In der vorliegenden Arbeit untersuchten wir die konsiliarisch-psychiatrische Versorgung eines großen Allgemeinkrankenhauses in Verbindung mit der Aufnahme auf eine Kriseninterventionsstation.Besonders interessierten uns Zusammenhänge zwischen der Häufigkeit des Auftretens von Suizidalität, psychiatrischer Krise und Übernahme von konsiliarisch-psychiatrisch untersuchten Patienten. Von insgesamt 6004 Patienten des Allgemeinkrankenhauses wurden in einem Zeitraum von 2 Monaten 227 (130 Frauen, 97 Männer) psychiatrisch untersucht. Am häufigsten wurden psychogene Reaktionen und Anpassungsstörungen (ICD-9: 308.0–309.9) mit 36.6%, am zweithäufigsten Suchterkrankungen (ICD-9: 303, 305.0, 304.0–304.9, 305.1–305.9) mit 26.8% diagnostiziert. In 90 Fällen lag eine psychiatrische Krise vor. Das Durchschnittsalter dieser Patienten war niedriger als das der Übrigen. Bei 91 Patienten fand man ein suizidales Syndrom. Es wurden 23 Patienten innerhalb und 7 nach Ablauf von 24 Std auf die Kriseninterventionsstation (KIS) übernommen.Mit Hilfe der Konfigurationsfrequenzanalyse (KFA) fanden wir 3 signifikante Typen: (1) Krisen-Patienten (N = 18), bei denen sowohl Suizidalitat, Krise und Ubernahme auf die Kriseninterventionsstation innerhalb von 24 Std zusammentraf; (2) typische Nicht-Krisen-Patienten (N = 111), bei denen keine der 3 Variablen bejaht wurde; (3) eine Gruppe (N = 48), die trotz des Vorliegens eines suizidalen Syndroms und einer aktuellen Krise nicht auf die KIS übernommen wurden.Bei der Gruppe von Patienten (N = 23), die eine angebotene Aufnahme auf die Kriseninterventionsstation ablehnten, bestätigte sich durch eine Nachuntersuchung nach Ablauf eines Jahres unsere Hypothese eines hohen Risikos.Die vorliegende Arbeit ist Herrn Prof. Dr. med. Wilhelm Feuerlein zum 65. Geburtstag gewidmet.  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