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   13857篇
  免费   399篇
  国内免费   352篇
耳鼻咽喉   153篇
儿科学   136篇
妇产科学   224篇
基础医学   1076篇
口腔科学   216篇
临床医学   1144篇
内科学   2373篇
皮肤病学   148篇
神经病学   1535篇
特种医学   407篇
外科学   849篇
综合类   951篇
现状与发展   1篇
一般理论   4篇
预防医学   1078篇
眼科学   408篇
药学   2732篇
  20篇
中国医学   620篇
肿瘤学   533篇
  2024年   6篇
  2023年   382篇
  2022年   876篇
  2021年   1262篇
  2020年   1320篇
  2019年   1578篇
  2018年   1447篇
  2017年   993篇
  2016年   718篇
  2015年   401篇
  2014年   806篇
  2013年   1543篇
  2012年   1360篇
  2011年   403篇
  2010年   297篇
  2009年   152篇
  2008年   137篇
  2007年   123篇
  2006年   104篇
  2005年   87篇
  2004年   38篇
  2003年   39篇
  2002年   25篇
  2001年   37篇
  2000年   32篇
  1999年   24篇
  1998年   18篇
  1997年   5篇
  1996年   17篇
  1995年   15篇
  1994年   12篇
  1993年   4篇
  1992年   3篇
  1990年   6篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1985年   58篇
  1984年   89篇
  1983年   34篇
  1982年   41篇
  1981年   37篇
  1980年   20篇
  1979年   12篇
  1978年   14篇
  1977年   8篇
  1976年   4篇
  1975年   12篇
  1974年   3篇
  1973年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
ABSTRACT

Early detection of apoptotic cells on histological slides is of major importance for both diagnostic and research areas. In the current study, the aim was to propose a convenient method to stain the mitochondria and establish whether hepatocytes undergoing apoptosis can be identified in tissue sections using the proposed method. Liver tissue from five adult chinchillas was fixed with 10% neutral buffered formalin for Goldner’s trichrome (GT) and Groat’s iron hematoxylin and eosin (HE) stains and with Kolster’s fixative for the Heidenhain’s iron hematoxylin procedure. The HE and GT-stained sections showed the morphological features consistent with apoptosis i.e., homogenous intensely acidophilic cytoplasm, cell shrinkage with an irregular outline, nuclear shrinkage with cloudy karyoplasm, and karyopyknosis in the late stage. Sections stained with Heidenhain’s iron hematoxylin method was used to pinpoint mitochondria and revealed cells which were undergoing the first stages of the apoptosis process i.e., disappearance of mitochondria from the cell, chromatin condensation and margination, paracentral localization of nucleoli, and vacuolated nuclei. In more advanced stages of apoptosis, cells presented significant nuclear and cytoplasmic changes. It was concluded that this is the first report targeting the mitochondria, by performing inexpensive histological staining techniques, in order to assess dead cells in situ.  相似文献   
42.
《Immunity》2022,55(5):879-894.e6
  1. Download : Download high-res image (223KB)
  2. Download : Download full-size image
  相似文献   
43.
Introduction: Growth failure in children is a frequent feature of childhood-onset Crohn’s disease (CD), and stunting can persist into adulthood. Growth is an important outcome by which to judge the effectiveness of therapies in children; currently available studies in CD children have focused on the short-term impact of treatments on growth, and there are limited data regarding the long-term effects of treatments upon growth.

Areas covered: We designed the present article to review whether the first treatment performed in newly diagnosed CD children may have a role on the future growth course. We conducted a systematic literature search to identify relevant studies published on the PubMed database from January 2002 up to now. We found only six surveys that documented mid-term growth course in newly diagnosed CD patients.

Expert commentary: In the last years there have been relevant advances in the clinical management of CD children; however, there is a lack of knowledge about the best strategy to reverse growth failure. Children treated with enteral nutrition have appropriate height and weight gain but do not reverse the growth course. Further surveys are required to better explore not only clinical outcomes but also long-term growth course following each therapeutic strategy.  相似文献   

44.
45.
Macrophages are known to release reactive oxygen species (O2?, 1O2, H2O2, OH·) in response to various membrane stimuliHowever, our studies show that phagocytic stimulation of macrophages is not necessarily accompanied by a stimulation of the oxidative burstWhereas IgG-opsonized erythrocytes were capable to induce phagocytosis and a chemiluminescence response, both being dependent on the number of IgG bound per erythrocyte, C3b-bearing erythrocytes were well ingested but failed to induce any chemiluminescence reactionFurthermore, stimulation of macrophages, via the Fc-receptors, seems to alter their functional state in regard to the activation of a receptor, which enables them to recognize membrane lesions on the target erythrocyteThe presence of IgG and membrane lesions, e.gthe C5b-9-complex of complement, induced a marked increase in chemiluminescence compared with stimulation by IgG-bearing particles aloneThe augmented response of macrophages was at least in part due to an additional release of H2O2, which was not liberated in response to IgG-bearing erythrocytesThis «Alesion recognizing receptor» in the macrophage membrane could not be activated by stimulation of C3b-receptors, indicating its functional linkage to the Fc-receptors.  相似文献   
46.
47.
48.
BackgroundPlatelet transfusion is required to treat haemo-oncology or trauma patients. Platelet apheresis (PA) performed with apheresis equipment has increased rapidly in recent years. Leucocyte-reduced platelet apheresis (LRPA) can reduce the risk of platelet refractoriness and febrile nonhemolytic transfusion reactions (FNHTRs) for transfusion. Accordingly, this study aimed to investigate and compare the platelet metabolic and functional responses between PA performed with Haemonetics and LRPA performed with Trima Accel cell separator.MethodsThe qualities of platelets collected through PA and LRPA were evaluated in terms of visual appearance, morphology, platelet-aggregation changes, metabolic activities, and bacterium-screening test during 5-day storage. Statistical analyses included two-sample t-test and generalised estimating equation(GEE) method.ResultsDuring 5-day storage in LRPA, residual leucocytes were all <1.0×106, and the parameters of platelet function were as follows: platelet aggregated to agonists such as adenosine 5′-diphosphate (ADP) and collagen, and the extent of shape change and pO2 showed no statistically significant difference between PA and LRPA. The hypotonic shock reaction (HSR) on days 0, 1, and 3 were significantly higher in LRPA than in PA (71.78±6.92 vs. 64.10±7.42; P=0.002; 71.53±8.98 vs. 62.96±9.84; P=0.007; 68.05±7.28 vs. 57.76±6.80; P<0.0001, respectively). Values of mean platelet volume (MPV) were statistically larger in PA than in LRPA on days 0, 1, and 3. On day 5, the swirling score was higher in LRPA than in PA. The mean lactate levels had no statistically significant difference between PA and LRPA. Moreover, no growth was observed through bacterium-screening test conducted on 40 samples.ConclusionComparison of LRPA and PA products collected from the Trima Accel and Haemonetics automated blood-collection systems, respectively, revealed that both products possessed good platelet qualities even though additional processes are needed to reduce leucocytes. Furthermore, investigating the outcomes of other apheresis instruments with focus on the safety of donors, products, and recipients is necessary.  相似文献   
49.
Peripheral blood mononuclear cells from patients with multiple myeloma, gastrointestinal tumors, and inflammatory bowel disease were analyzed for binding of various lectins. The results demonstrated that in most of the patients with multiple myeloma a significantly increased percentage of cells positive for Lotus tetragonolobus agglutinin (LTA), peanut agglutinin (PNA), soybean agglutinin (SBA), and wheat germ agglutinin (WGA), and a decreased number of Agaricus bisporus agglutinin (ABA) positive cells were present as compared to a normal control group. This could not be shown in malignant or inflammatory disorders of the gastrointestinal tract where only some patients exhibited an increased PNA and LTA binding, respectively. Patients with the systemic malignant disease differed from patients with solid localized tumors by a significantly altered number of ABA, LTA and SBA-positive peripheral blood mononuclear cells. Double fluorescence studies using monoclonal antibodies and lectins revealed that most of the cells expressing receptors for ABA had also receptors for OKT3, whereas most of the cells with receptors for LTA, PNA SBA, and WGA were found to be positive for OKM.  相似文献   
50.
Clinical electromyographic (EMG) biofeedback was an outgrowth of diagnostic electromyography and research on the fine control of motor units. In rehabilitation, EMG biofeedback has gained a firm place in the treatment of upper motor neuron lesions, particularly in retraining muscles and inducing relaxation of spastic muscles of stroke patients. In cerebral palsy and musculoskeletal disturbances, additional feedback transducers (e.g., electrogoniometers, pressure-sensitive and position-sensing devices) are gaining wider use. Spasmodic torticollis has proved to be particularly suitable for behavioral methods of treatment, including EMG feedback.  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