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   993篇
  免费   44篇
耳鼻咽喉   3篇
儿科学   33篇
妇产科学   7篇
基础医学   145篇
口腔科学   9篇
临床医学   53篇
内科学   136篇
皮肤病学   26篇
神经病学   151篇
特种医学   40篇
外科学   129篇
综合类   11篇
一般理论   2篇
预防医学   19篇
眼科学   55篇
药学   88篇
肿瘤学   130篇
  2022年   9篇
  2020年   12篇
  2019年   6篇
  2018年   12篇
  2017年   10篇
  2016年   14篇
  2015年   16篇
  2014年   13篇
  2013年   19篇
  2012年   49篇
  2011年   68篇
  2010年   27篇
  2009年   33篇
  2008年   57篇
  2007年   69篇
  2006年   54篇
  2005年   51篇
  2004年   54篇
  2003年   53篇
  2002年   61篇
  2001年   16篇
  2000年   5篇
  1999年   11篇
  1998年   14篇
  1997年   8篇
  1996年   8篇
  1993年   5篇
  1991年   6篇
  1988年   8篇
  1987年   11篇
  1986年   19篇
  1985年   11篇
  1984年   5篇
  1983年   12篇
  1982年   10篇
  1981年   9篇
  1980年   8篇
  1979年   11篇
  1978年   21篇
  1977年   18篇
  1976年   11篇
  1975年   13篇
  1974年   12篇
  1973年   14篇
  1972年   7篇
  1971年   7篇
  1970年   11篇
  1969年   10篇
  1968年   8篇
  1967年   4篇
排序方式: 共有1037条查询结果,搜索用时 15 毫秒
21.
Monatsschrift Kinderheilkunde - Eine adäquate Energie- und Nährstoffversorgung ist Grundlage für ein gesundes Wachstum und Voraussetzung für die Erhaltung von Gesundheit und...  相似文献   
22.
After allantoic injection of chick embryos with a known amount of influenza virus, the process of adsorption of the agent onto host cells and infection of them can be interrupted at a given time by the administration of large quantities of heterologous virus inactivated by irradiation. A sudden great increase in the amount of free virus in the allantoic fluid occurring after 6 hours in the case of the PR8 strain, and 9 hours in that of the Lee strain, indicates that the untreated virus associated with the host cells has multiplied. The length of the period preliminary to this increase remains the same even though the concentration of the original inoculum is varied over a wide range. Since administration of the irradiated virus leaves no susceptible host cells, because of the interference phenomenon, and further adsorption of active virus is minimized or entirely prevented, practically the entire new increment of virus can be found in the allantoic fluid and assayed; for every ID50 adsorbed about 50 ID50 are released. Homologous irradiated virus, on the other hand, when injected after infection of the allantoic sac, reduces the yield of virus to a more or less considerable extent. Some inhibitory effect can still be observed when the homologous irradiated virus is given several hours after infection. This effect is linked to the virus particle and destroyed by prolonged irradiation.  相似文献   
23.
The aim of the study was to isolate from the clinical history and examination, symptoms, or combination of symptoms highly suspicious for intestinal infiltration in endometriosis patients. In a prospective study, preoperative anamnesis on defecation problems and pain symptoms was correlated with the vaginal examination and the laparoscopic findings in 2,000 consecutive patients with suspicion of intestinal endometriosis; 65.7% of the patients reported a typical symptomatology combining left-sided pelvic pain irradiating systematically to the back and occasionally to the left leg, with dyschesia, abdominal bloating, and/or sensation of a doubt masse in the left lower or middle abdomen, sometimes rectorrhagia and an improvement in the pain after defecation. In the absence of a palpable endometriotic nodule of the rectovaginal space, the combination of this symptoms correlated in 93.7% of the patients with an outlet constipation syndrome due to a significant elongation with kinking of the rectosigmoide. In the patients with a palpable endometriotic nodule of the posterior fornix (n = 712), the combination of an apareunia with the apparition of constipation for 2–3 days at the beginning of the period bleeding followed by a diarrhea until the end of the period shows a positive predictive value for deep intestinal infiltration of 95%. In all endometriosis patients undergoing a laparoscopy for pain and intestinal disorders, the elongation of the rectosigmoide must be perceived and recognized as a potential cause for an outlet constipation syndrome which can be cured easily by a left-sided sigmoidopexy. In patients with a macroscopic endometriotic nodule of the posterior fornix, the presence of an apareunia and the apparition of constipation at the beginning of the menstruation followed 2–3 days later by a diarrhea are strong arguments for an invasive intestinal endometriosis, and those patients must be primarily referred to a tertiary referral center. No financial support was received for this study.  相似文献   
24.
PURPOSE: Somatostatin receptor (sst) targeting is an established method to image and treat sst-positive tumors. Particularly, neuroendocrine tumors express the receptor subtype 2 in high density, but sst1, sst3, sst4, and sst5 are also expressed to some extent in different human tumors. Currently used targeting peptides mainly have sst2 affinity. We aimed at developing (radio)peptides that bind with high affinity to all receptor subtypes. EXPERIMENTAL DESIGN: Carbocyclic octapeptides were coupled with macrocyclic chelators for radiometal labeling. Affinity, internalization, and agonist potencies were determined on sst1- to sst5-expressing cell lines. Biodistribution was determined on nude mice bearing HEK-sst2 or AR4-2J and HEK-sst3 tumors. RESULTS: High affinity to all receptor subtypes was found. Y(III)-KE88 showed agonistic properties at all five sst receptor subtypes as it inhibits forskolin-stimulated cyclic AMP production. Surprisingly, very low or even absent sst2 receptor internalization was found compared with currently clinically established octapeptides, whereas the sst3 internalization was very efficient. Biodistribution studies of [(111)In]KE88 and [(67)Ga]KE88/[(68)Ga]KE88 reflected the in vitro data. In nude mice with s.c. implanted sst2 (HEK-sst2, AR4-2J)-expressing and sst3 (HEK-sst3)-expressing tumors, high and persistent uptake was found in sst3-expressing tumors, whereas the uptake in the sst2-expressing tumors was lower and showed fast washout. The kidney uptake was high but blockable by coinjection of lysine. CONCLUSION: This peptide family shows pansomatostatin potency. As radiopeptides, they are the first to show a full pansomatostatin profile. Despite some drawback, they should be useful for imaging sst2-expressing tumors with short-lived radiometals, such as (68)Ga, at early time points and for sst3-expressing tumors at later time points with longer-lived radiometals, such as (64)Cu or (86)Y.  相似文献   
25.
Transient immunodeficiency during asymptomatic Epstein-Barr virus infection   总被引:2,自引:0,他引:2  
In vivo and in vitro humoral and cellular immune responses were studied in a 2 1/2-year-old girl immediately before, during, and after an asymptomatic infection with Epstein-Barr virus. During the acute EBV infection, the patient's peripheral blood mononuclear cells were deficient in immunoglobulin synthesis and suppressed the in vitro immunoglobulin synthesis of normal allogeneic cells. In vitro mitogen transformation of lymphocytes was reduced. In vivo antibody responses to the T cell-dependent antigens bacteriophage phi X 174 and Keyhole limpet hemocyanin were markedly depressed. These studies suggest that suppressor cells induced during acute EBV infection not only suppress immunoglobulin synthesis in vitro, but also interfere with in vivo antibody synthesis.  相似文献   
26.
27.
Three new pyrone glucosidic derivatives, together with the known pyromeconic acid glucoside, three acytelenes and two eudesmanes, were obtained from the aerial parts of Conyza albida. The structures were elucidated by high field NMR spectroscopy.  相似文献   
28.
Role of taurine accumulation in keratinocyte hydration   总被引:2,自引:0,他引:2  
Epidermal keratinocytes are exposed to a low water concentration at the stratum corneum-stratum granulosum interface. When epithelial tissues are osmotically perturbed, cellular protection and cell volume regulation is mediated by accumulation of organic osmolytes such as taurine. Previous studies reported the presence of taurine in the epidermis of several animal species. Therefore, we analyzed human skin for the presence of the taurine transporter (TAUT) and studied the accumulation of taurine as one potential mechanism protecting epidermal keratinocytes from dehydration. According to our results, TAUT is expressed as a 69 kDa protein in human epidermis but not in the dermis. For the epidermis a gradient was evident with maximal levels of TAUT in the outermost granular keratinocyte layer and lower levels in the stratum spinosum. No TAUT was found in the basal layer or in the stratum corneum. Keratinocyte accumulation of taurine was induced by experimental induction of skin dryness via application of silica gel to human skin. Cultured human keratinocytes accumulated taurine in a concentration- and osmolarity-dependent manner. TAUT mRNA levels were increased after exposure of human keratinocytes to hyperosmotic culture medium, indicating osmosensitive TAUT mRNA expression as part of the adaptation of keratinocytes to hyperosmotic stress. Keratinocyte uptake of taurine was inhibited by beta-alanine but not by other osmolytes such as betaine, inositol, or sorbitol. Accumulation of taurine protected cultured human keratinocytes from both osmotically induced and ultraviolet-induced apoptosis. Our data indicate that taurine is an important epidermal osmolyte required to maintain keratinocyte hydration in a dry environment.  相似文献   
29.
Kinner BJ  Best R  Falk K  Thon KP 《The Journal of trauma》2002,53(6):1094-101; discussion 1102
BACKGROUND: The treatment of displaced intra-articular calcaneal fractures remains controversial, because of difficulties in assessing the outcome. The goal of this study, therefore, was to compare different outcome measurements with gait analysis, using dynamic pedography. METHODS: Twenty patients with operatively treated displaced intra-articular calcaneal fractures were followed up clinically and radiographically. In addition, foot pressure was measured using dynamic pedography. RESULTS: No significant difference was found between the two clinical outcome scores used (p = 0.08); both revealed good results. Dynamic pedography, however, showed a shift of the maximum impact and roll-off of the foot to the lateral side, as well as a widening of these zones in the heel and on the sole in 14 of 20 patients. CONCLUSION: These results indicate that traditional outcome measurements underestimate functional deficits in our patients. Monitoring plantar pressure distribution might therefore be a useful tool for assessing foot function in these patients.  相似文献   
30.
There is an increasing need for in vitro testing of compounds for topical application. Reconstructed epidermal models may provide a suitable and relevant model for screening compounds that may affect the activities of phase I and II enzymes involved in epidermal detoxification. In this study, we measured the activity of a phase I enzyme, cytochrome P450 IA1, i.e. 7-ethoxyresorufin-O-deethylase (EROD) and 7-ethoxycoumarin-O-deethylase (ECOD) activities, and that of a phase II enzyme, glutathione S-transferase (GST). The enzyme activities were determined in cultured keratinocytes, reconstructed epidermal models and samples of human epidermis or hair follicle. EROD activity was detected in cultured keratinocytes and was induced by 3-methylcholanthrene (3-MC) and beta-naphthoflavone. The level of induction increased with increasing confluence. Induced EROD activity could be inhibited by clotrimazole in a dose-dependent manner. However, EROD activity was not detected in either hair follicles or untreated epidermal models but could be induced by 3-MC. The ability to induce EROD activity in epidermal models was batch dependent, and clotrimazole was able to inhibit the induced EROD activity. ECOD activity was detected in untreated models and paralleled EROD activity. GST activity was detected in cultured keratinocytes and all epidermal models. GST activity in models was equal or higher than the activity in epidermal samples. Reconstructed skin models may be useful to study the effects of non-water-soluble topical formulations on xenobiotic metabolism.  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