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   1300篇
  免费   63篇
  国内免费   14篇
耳鼻咽喉   6篇
儿科学   35篇
妇产科学   44篇
基础医学   184篇
口腔科学   8篇
临床医学   80篇
内科学   268篇
皮肤病学   14篇
神经病学   168篇
特种医学   43篇
外科学   120篇
综合类   13篇
一般理论   1篇
预防医学   112篇
眼科学   22篇
药学   130篇
中国医学   6篇
肿瘤学   123篇
  2023年   4篇
  2022年   25篇
  2021年   37篇
  2020年   25篇
  2019年   23篇
  2018年   39篇
  2017年   26篇
  2016年   36篇
  2015年   33篇
  2014年   47篇
  2013年   61篇
  2012年   87篇
  2011年   113篇
  2010年   53篇
  2009年   42篇
  2008年   82篇
  2007年   91篇
  2006年   103篇
  2005年   50篇
  2004年   80篇
  2003年   70篇
  2002年   71篇
  2001年   17篇
  2000年   11篇
  1999年   13篇
  1998年   11篇
  1997年   6篇
  1996年   9篇
  1995年   5篇
  1994年   4篇
  1993年   8篇
  1992年   7篇
  1991年   11篇
  1990年   9篇
  1989年   4篇
  1988年   5篇
  1985年   5篇
  1984年   8篇
  1983年   4篇
  1982年   4篇
  1981年   6篇
  1980年   3篇
  1977年   2篇
  1975年   3篇
  1974年   2篇
  1973年   2篇
  1972年   2篇
  1971年   2篇
  1968年   2篇
  1967年   2篇
排序方式: 共有1377条查询结果,搜索用时 15 毫秒
61.
Chemokines are involved in the pathogenesis of multiple sclerosis. The aim of this study was to determine the impact of steroid therapy on the levels of CCL2 and CCL5 chemokines. The study encompassed 30 patients with clinically definite relapsing-remitting multiple sclerosis who were treated with methylprednisolone due to the relapse of the disease. The control groups consisted of 20 patients during the stable stage of relapsing-remitting multiple sclerosis and of 15 patients with noninflammatory diseases of the nervous system. Both chemokines were markedly expresssed in serum by enzyme-linked immunosorbent assay. During relapse, the levels of both chemokines differed significantly from the levels measured in both control groups. After the methylprednisolone treatment, the chemokine levels changed significantly: the levels of CCL2 increased, whilst the levels of CCL5 decreased. These alterations did not correlate with the clinical state of the patients or with the therapeutic effect of the treatment and indicated that the inflammatory reaction accompanying the relapse was receding.  相似文献   
62.
The aim of the study was to determinate the serum leptin level, glucose concentration, lipids (total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride) and thyroid hormones level (triiodothyronine, thyroid stimulating hormone and free thyroxine) in a group of prepubertal children with simple obesity. Fourfold higher leptin concentration in obese (23.3 +/- 11.8 ng/mL) in comparison to a group of slim children (6.8 +/- 2.7 ng/mL), (p<0.0001) was shown. There was no significant difference in serum glucose level (87.3 +/- 9.7 mg/dL) between both studied groups. In obese subjects we showed higher triglyceride, insignificantly lower HDL-C concentrations and invariable other lipid fractions. Mean values of triiodothyronine (T3) were 3.0 +/- 0.7 nmol/L in obese children and 2.8 +/- 0.8 nmol/L in slim children. On the contrary, mean values of thyroid stimulating hormone (TSH) were 2.5 +/- 1.7 mIU/L and 2.8 +/- 0.7 mIU/L in the group of obese and normal children respectively. Free thyroxine (FT4) concentrations in our obese children were lower (11.5 +/- 2.9 pmol/L) than in slim subjects (14.6 +/- 3.1 pmol/L) but were within the reference range. The results obtained indicate that in children with simple obesity there was no dyslipidemia connected with leptin and thyroid hormones levels. However, higher triglyceride and lower HDL-C concentrations suggest a necessity of monitoring the body mass index and lipid profile in these patients.  相似文献   
63.
A 55-year-old man was admitted to our Department four weeks after anterior myocardial infarction. A large, mobile thrombus was diagnosed on echocardiography. On the third day of hospitalization systemic arterial embolism with left femoral artery localization occurred. The embolus was removed surgically. During 3-month follow-up the patient received anticoagulant therapy with complete resolution of ventricular thrombus. Therapeutic options in this case are discussed.  相似文献   
64.
Activated platelets release microvesicles, which express procoagulant activity. The mechanism by which vesicles are formed is not entirely clear. This study was undertaken to determine whether a link exists between the operation of the plasma membrane Na(+)/H(+) exchanger (NHE) and vesiculation. It was found, that platelets treated with NHE-simulating monensin and the sodium influx-inducing gramicidin (without concomitant H+ efflux) produced vesicles demonstrating procoagulant activity. Alkalinization of platelet cytosol by NH4Cl failed to evoke vesicle release. Collagen and phorbol ester (PMA)-evoked vesiculation was diminished in the presence of 5-(N-ethyl-N-isopropyl amiloride) (EIPA, inhibitor of NHE) or GF 109203X (inhibitor of protein kinase C). Vesicle formation induced by collagen, PMA, and the calcium ionophore A23187 was less pronounced in the absence of external Na+. In comparison with collagen, thrombin was a stronger inducer of vesiculation. Platelets stimulated by thrombin, collagen, and PMA accumulated 22Na+, a phenomenon inhibited in the presence of EIPA. Collagen-evoked vesicle formation started with aggregation but culminated after its completion. The data indicate a significant contribution of the Na(+)/H(+) exchanger in the formation of microvesicles by porcine platelets.  相似文献   
65.
66.
The influence of the blockade of group I metabotropic glutamate receptors (mGluRs) by AIDA [(RS)-1-aminoindan-1,5-dicarboxylic acid] on some behavioral effects was tested in control groups of rats and in rats that underwent short-term hypoxia. We used the following methods: the open field test, the passive avoidance test and the elevated "plus" maze test. In rats without hypoxia, AIDA (100 nmol icv) decreased the number of crossings in the open field test, impaired acquisition, improved consolidation and did not influence retrieval in the passive avoidance situation and was ineffective in the elevated "plus" maze. Short-term hypoxia (2% O2, 98% N2), as a model of experimentally induced amnesia, significantly inhibited locomotor and exploratory activity and profoundly impaired acquisition, consolidation and retrieval processes and did not exhibit proanxiogenic or anxiolytic effect in elevated "plus" maze. AIDA (100 nmol icv) used before hypoxia significantly improved consolidation and retrieval processes, but had no effect on acquisition and did not significantly influence all parameters of the elevated "plus" maze test. The obtained results suggest that AIDA, the selective antagonist of group I mGluRs, had beneficial effects on consolidation and retrieval of passive avoidance in rats undergoing hypoxia.  相似文献   
67.
The study was designed to investigate the effects of NMDA receptor agonist on the behavioral activity in rats with experimental diabetes mellitus (DM). Experimental diabetes was induced by a single intravenous injection of streptozotocin at a dose of 65 mg/kg dissolved in saline. Rats treated with saline (0.9%) served as control. Stimulation of the NMDA glutamatergic receptor was evoked by ip injection of an agonist N-methyl-D-aspartate acid (NMDA), at a dose of 15 mg/kg 30 min before the experiments. Memory motivated affectively was evaluated in the passive avoidance responses. Possible influence of the treatment on locomotor and exploratory activity was tested in open field test. Moreover, the working memory was evaluated in the T-maze test. We observed that NMDA given alone did not have significant influence on motor activity in control rats except for the number of bar approaches, while in rats with DM NMDA significantly increased motor activity in the open field test. In rats with experimental diabetes, NMDA increased acquisition, but it did not have any significant influence on consolidation and recall of a passive avoidance responses. NMDA at the tested dose had no influence on a passive avoidance latency in control rats. In the T-maze test, NMDA increased working memory but only in diabetic rats.  相似文献   
68.
The energy value and content of nutritive components in nursery school meals have been evaluated by analytical method and calculated by Nutritionist IV computer program with Polish data base. A significant correlation between analysed and calculated values has been observed. An average nursery school meal covered recommended intake of iron, calcium, zinc, vit. B1 and % of energy from proteins, fats and carbohydrates. An average nursery school meal covered above recommended intake of total energy and % of energy from saturated fatty acids, proteins, fats, cholesterol, carbohydrates, fiber, magnesium, potassium, phosphorus, copper and vitamins A, E, C, B2 i B6. Only the average content of vit. PP and % of energy from mono- and polyunsaturated fatty acids in analysed nursery school meals has been below the recommended intake. The results indicate that there is a tendency to supply energy and some of nutritive components in nursery school meals above the recommended intake.  相似文献   
69.
70.
Coexistence of B-cell chronic lymphocytic leukemia (B-CLL) and chronic myelomonocytic leukemia (CMML) is an unusal event, and to our knowledge, only four such cases have been reported in the literature. We report a 68-year-old white woman in whom these two diseases were diagnosed concomitantly. The diagnosis was made on the basis of peripheral blood count, morphology and immunophenotyping, and bone marrow cytology and histology. Interphase FISH analysis detected a 13q14.3 deletion in lymphocytes nuclei and no such abnormality in monocytes nuclei. The PCR analysis of IgH gene rearrangement in the bone marrow, as well as the peripheral blood lymphocytes, showed two different monoclonal IgH configurations as the result of biallelic clonal rearrangement of IgH genes suggesting an origin of lymphocytes from B-cell progenitors. The patient was originally treated with prednisone 1 mg/kg/day because of progressive significant thrombocytopenia, without improvement. Subsequently, she received one course of cladribine (2-CdA). Significant reduction of lymphocytes in the peripheral blood was observed. However, rapid increase of monocytes was seen shortly after the 2-CdA treatment. Subsequently, she received hydroxyurea (1.5 g/day) without hematological improvement. The patient died in January 2003, three months after diagnosis because of progression of both leukemias and associated pneumonia. Possible etiopathogenic relationship between both disorders is discussed.  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