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   383篇
  免费   53篇
  国内免费   52篇
耳鼻咽喉   3篇
儿科学   16篇
妇产科学   5篇
基础医学   41篇
口腔科学   6篇
临床医学   77篇
内科学   120篇
皮肤病学   7篇
神经病学   7篇
特种医学   72篇
外科学   45篇
综合类   9篇
预防医学   30篇
眼科学   1篇
药学   36篇
肿瘤学   13篇
  2022年   3篇
  2021年   4篇
  2019年   5篇
  2018年   6篇
  2016年   6篇
  2015年   4篇
  2014年   8篇
  2013年   10篇
  2012年   7篇
  2011年   17篇
  2010年   18篇
  2009年   10篇
  2008年   8篇
  2007年   48篇
  2006年   17篇
  2005年   21篇
  2004年   6篇
  2003年   6篇
  2002年   9篇
  2001年   10篇
  2000年   8篇
  1999年   8篇
  1998年   18篇
  1997年   11篇
  1996年   23篇
  1995年   13篇
  1994年   19篇
  1993年   12篇
  1992年   3篇
  1991年   5篇
  1990年   9篇
  1989年   12篇
  1988年   8篇
  1987年   11篇
  1986年   12篇
  1985年   8篇
  1984年   8篇
  1983年   4篇
  1981年   6篇
  1980年   4篇
  1979年   3篇
  1978年   3篇
  1977年   10篇
  1976年   8篇
  1975年   7篇
  1973年   7篇
  1971年   4篇
  1968年   2篇
  1967年   2篇
  1962年   2篇
排序方式: 共有488条查询结果,搜索用时 15 毫秒
1.
2.
Summary Six hundred and thirty four adolescents and children aged three days to 17 years treated with ciprofloxacin on a compassionate basis were analysed for drug safety. 62% of the ciprofloxacin courses were given to patients with respiratory tract infection, primarily those with acute pulmonary exacerbation of cystic fibrosis. The mean daily oral dose was 25.2 mg/kg body weight. The duration of treatment ranged from one to 880 days (mean 22.8 days). Because of the arthropathogenic potential of quinolones in juvenile animals special emphasis was placed on the evaluation of musculoskeletal adverse events. Arthralgia considered by the treating physicians to be related to ciprofloxacin was reported in eight children, all of whom were females. Arthralgia resolved in all children. Some of these children were given subsequent courses of ciprofloxacin with no complaints of arthralgia. Overall, the safety profile of ciprofloxacin in children is not substantially different from that of adults.
Verträglichkeit von Ciprofloxacin bei Kindern unter besonderer Beachtung der Gelenke. Auswertung weltweit dokumentierter Problemfälle
Zusammenfassung Die Verträglichkeit des Ciprofloxacin nach Anwendung bei 634 Jugendlichen und Kindern im Alter von drei Tagen bis 17 Jahren wurde analysiert. 62% der Behandlungen mit Ciprofloxacin erhielten Patienten mit Atemwegsinfektionen, insbesondere mit akuter pulmonaler Exazerbation der Mukoviszidose. Der Mittelwert der oralen Tagesdosis war 25,2 mg/kg Körpergewicht. Die Therapiedauer variierte zwischen 1 und 880 Tagen (Mittelwert 22,8 Tage). Wegen der gelenkknorpelschädigenden Wirkung der Chinolone bei juvenilen Versuchstieren wurde besondere Aufmerksamkeit der Beurteilung der mit Gelenken verbundenen Nebenerscheinungen gewidmet. Arthralgie, die von den behandelnden Ärzten als Folge der Ciprofloxacin-Behandlung beurteilt wurde, ist bei acht Kindern berichtet worden. Alle waren weiblich. Die Arthralgie verschwand bei allen Kindern. Einige dieser Kinder erhielten nachträgliche Behandlungen mit Ciprofloxacin ohne Auftreten arthralgischer Beschwerden. Generell unterschied sich das Verträglichkeitsprofil bei Kindern nicht wesentlich von dem der Erwachsenen.
  相似文献   
3.
Uroscopy in the 21st century: high-field NMR spectroscopy   总被引:1,自引:1,他引:0  
From the experiments described, it can be seen that there are different research approaches that can be taken and these are summarized in Table 1. Whereas much scientific research is principally hypothesis led, there remains, nevertheless, an important place for exploratory research. High resolution NMR can measure, directly and simultaneously, a wide range of endogenous metabolites in biological fluids and has the unique capability of providing structural information on the metabolites detected. It has proved to be a powerful research tool with which to study inherited metabolic diseases, renal disease, drug metabolism, and toxicity, and can be used to monitor the effects of drug therapy. For instance, by using a library of experimental toxins one can map the metabolic profile of site-specific nephron injury. With this approach in man one could eventually take an unknown disease such as Balkan nephropathy and predict the initial site of tubular injury, the mode of injury and therefore the kind of toxin capable of producing that injury. NMR spectroscopic techniques are still advancing rapidly, with ever increasing sensitivity and sophistication of NMR pulse sequences to enhance structural elucidation in complex mixtures. Given the advances in directly coupled HPLC-NMR and even HPLC-NMR-mass spectroscopy it is likely that these technologies in conjunction with pattern recognition will make major contribution to our understanding of renal processes and provide new diagnostic insights in the 21st century.   相似文献   
4.
A flow cytometric assay has been developed to detect and quantitate human immunodeficiency virus (HIV)-infected peripheral blood mononuclear cells obtained from HIV-seropositive patients. Peripheral blood was obtained from patients attending an acquired immune deficiency syndrome clinic, and mononuclear cells were separated by centrifugation onto Ficoll-Hypaque. The cell layer at the interface was removed, washed in phosphate-buffered saline without Ca2+ and Mg2+, and fixed with 90% methanol, and intracellular HIV antigens were detected by indirect immunofluorescence with monoclonal antibodies to HIV antigens as the primary antibody and fluorescein isothiocyanate-conjugated goat anti-mouse immunoglobulin G F(ab')2 antibody as the secondary antibody. DNA content was determined by propidium diiodide staining after RNase treatment. These fluorochrome-treated cells were analyzed for two-color fluorescence by flow cytometry. The results showed that HIV-infected cells in peripheral blood that have been treated with monoclonal antibodies to the p24 or nef antigens of HIV can be detected and quantitated by flow cytometry. The percentage of p24 antigen-positive mononuclear cells had a significant correlation (P = 0.0001) with the clinical status of the patient, i.e., those with a high percentage of p24 antigen-positive cells had a poorer prognosis than those with a lower percentage of p24 antigen-positive mononuclear cells. In addition, for those in Centers for Disease Control groups III and IV, there was an inverse correlation between the percentage of p24 antigen-positive mononuclear cells and the number of T4 cells. However, cell-associated antigen detection by flow cytometry did not correlate with detection of antigen in sera of HIV-seropositive patients by the standard antigen capture enzyme-linked immunosorbent assay. This lack of correlation was probably due to the presence of immune complexes in the sera of HIV-seropositive patients. These results suggest that flow cytometry can be used as a rapid, sensitive, and quantitative assay system for the determination of the antigen status of HIV-seropositive patients and that it may be more useful as an indicator of disease progression than the currently used antigen detection methods.  相似文献   
5.

Background  

Correct diagnosis in psychiatry may be improved by novel diagnostic procedures. Computerized Decision Support Systems (CDSS) are suggested to be able to improve diagnostic procedures, but some studies indicate possible problems. Therefore, it could be important to investigate CDSS systems with regard to their feasibility to improve diagnostic procedures as well as to save time.  相似文献   
6.
Cystic hypersecretory carcinoma (CHC) is a rare variant of intraductal carcinoma. A CHC in a 50-year-old woman was excised and processed for light and electron microscopy and immunohistochemistry. The tumor had a marked cystic appearance. The walls of the cysts consisted of epithelial and myoepithelial cells and a well-developed basement membrane. The epithelial cells contained well-developed rough-surfaced endoplasmatic reticulum and Golgi apparatus. Secretory granules were not detected, with the exception of a few mucus-producing cells. The secretion was predominantly homogenous, reminiscent of thyroid colloid, and demonstrated distinct PAS positivity. The cells displayed a strong labeling with epithelial membrane antigen (EMA) and EMA-positive structures were observed within the intraluminal secretion, too. Some of these were stained by alcian blue. In addition, the colloid-like material was admixed with mucus showing a filamentous internal structure and lipid droplets resulting in some heterogenity of the secretion. Intraductal micropapillary proliferation in some of the cysts and adjacent nondistended ducts was a further defining feature of the tumor. Steroid hormone receptor and Ki-67 proliferation marker immuno his Tochemistry showed scattered positivity among the tumor cells. These results are in agreement with previous observations and further clarify the nature of this low-grade in situ cancer.  相似文献   
7.
The introduction of a replication-inhibiting lesion into the DNA of Escherichia coli generates the induced, multigene SOS response. One component of the SOS response is a marked increase in mutation rate, dependent on RecA protein and the induced mutagenesis proteins UmuC and UmuD. A variety of previous indirect approaches have indicated that SOS mutagenesis results from replicative bypass of the DNA lesion by DNA polymerase III (pol III) holoenzyme in a reaction mediated by RecA, UmuC, and a processed form of UmuD termed UmuD'. To study the biochemistry of SOS mutagenesis, we have reconstituted replicative bypass with a defined in vitro system containing purified protein and a DNA substrate with a single abasic DNA lesion. The replicative bypass reaction requires pol III, UmuC, UmuD', and RecA. The nonprocessed UmuD protein does not replace UmuD' but inhibits the bypass activity of UmuD', perhaps by sequestering UmuD' in a heterodimer. Our experiments demonstrate directly that the UmuC-UmuD' complex and RecA act to rescue an otherwise stalled pol III holoenzyme at a replication-blocking DNA lesion.  相似文献   
8.
9.

BACKGROUND:

Flavonoids are polyphenolic substances with antioxidant properties, and they are found in different vegetables and fruits. Epidemiological studies have shown that the consumption of flavonoids reduces the prevalence of cardiovascular diseases. The use of synthetic antioxidants, however, has been limited because of their toxicity. Therefore, medical researchers have intensified their quest to find natural antioxidants.

OBJECTIVES:

To investigate the effect of several pure flavonoids, such as kaempferol, quercetin, morin and rutin, on red blood cell hemolysis and evaluate their -SH capacity as an indicator of membrane protection.

METHODS:

The rate of hemolysis and cell membrane -SH capacity were determined by spectrophotometry. Red blood cell peroxidation was induced using 2,2′-azo-bis-(2-amidinopropane) dihydrochloride. The effect of each flavonoid on hemolysis was examined at three concentrations (0.5 μg/mL, 5 μg/mL and 10 μg/mL), however, only the greatest concentration (10 μg/mL) of each flavonoid was used to study the effect on -SH groups.

RESULTS:

In all cases, the antioxidant activity was dose-dependent. Rutin showed the highest inhibitory effect on hemolysis among flavonoids (42.5%). The protective effect of kaempferol, rutin and morin against -SH group oxidation measured 7.7%, 23.3% and 26.4%, respectively.

CONCLUSIONS:

Results showed that flavonoids and flavonoid-containing plants can be used as natural antioxidants for the treatment and prevention of disease conditions, the pathogenesis of which is mediated by lipid peroxidation.  相似文献   
10.
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