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   1289篇
  免费   30篇
  国内免费   7篇
耳鼻咽喉   72篇
儿科学   66篇
妇产科学   55篇
基础医学   151篇
口腔科学   16篇
临床医学   68篇
内科学   303篇
皮肤病学   18篇
神经病学   150篇
特种医学   10篇
外科学   72篇
综合类   6篇
预防医学   77篇
眼科学   46篇
药学   151篇
中国医学   3篇
肿瘤学   62篇
  2023年   3篇
  2022年   7篇
  2021年   21篇
  2020年   6篇
  2019年   13篇
  2018年   12篇
  2017年   9篇
  2016年   18篇
  2015年   27篇
  2014年   21篇
  2013年   39篇
  2012年   73篇
  2011年   87篇
  2010年   33篇
  2009年   35篇
  2008年   86篇
  2007年   114篇
  2006年   141篇
  2005年   127篇
  2004年   110篇
  2003年   98篇
  2002年   124篇
  2001年   8篇
  2000年   5篇
  1999年   4篇
  1998年   8篇
  1997年   7篇
  1996年   5篇
  1994年   2篇
  1993年   3篇
  1992年   8篇
  1991年   8篇
  1990年   5篇
  1989年   7篇
  1988年   3篇
  1987年   4篇
  1985年   2篇
  1984年   5篇
  1983年   2篇
  1982年   2篇
  1980年   2篇
  1979年   3篇
  1978年   5篇
  1977年   2篇
  1976年   4篇
  1975年   2篇
  1974年   3篇
  1973年   3篇
  1972年   2篇
  1971年   4篇
排序方式: 共有1326条查询结果,搜索用时 31 毫秒
51.
Addison-Biermer's anaemia is an autoimmune disease. It may coexist with other auto-aggressive diseases, precede them or join the other existing autoimmune diseases. It most often accompanies the Hashimoto disease but also may coexist polyglandular autoimmune syndrome (PGA). Three types of PGA are distinguished: PGA1--Blizzard's Syndrome, PGA2--Schmidt's Syndrome, and PGA3. The latter, unlike the remaining ones, is characterized by normal function of adrenal glands. Addison-Biermer's anaemia occurrence may be often difficult to diagnose as coexisting illnesses might ouflage its clinical symptoms. The aim of this paper was to analyse patients with different types of PGA with coexisting Addison-Biermer's anaemia. Group of 24 individuals was analysed: 2 women with PGA1, 10 patients with PGA2, 10 patients with PGA3. In 2 remaining ones PGA was not confirmed. Addison-Biermer's anaemia occurred in 7 patients (2 with PGA2 and 5 with PGA3 syndrome). Decreased concentration of vitamin B12 was diagnosed in 3 individuals among 24 examined patients (1 with type 3 and 2 with type 2), as well in 2 patients with unconfirmed PGA. Addison-Biermer's anaemia was not observed in patients with PGA1. We observed that megaloblastic anaemia occurred characteristic schedule depending on appearance of autoimmune diseases: in PGA2--many years after other immunopathies were found, in PGA3--as first auto-aggressive disease. Our analysis suggests the necessity of detailed check-ups on patients with Addison-Biermer's anaemia, as with time they may develop other diseases, especially hypothyroidism and/or PGA failure. On the contrary, in individuals with thyroid gland diseases and PGA syndromes further checkups should be megaloblastic anaemia-sensitive. In both cases it is important to consider substitutive treatment. The possibility of family coexisting both pernicious anaemia and autoimmune endocrinopathies needs diagnostics of members of the patient's family.  相似文献   
52.
Mycologic investigations were carried out in subjects suffering from upper respiratory tract ailments. The material for assessment was collected from various ontocenoses. Species of fungal strains were determined by means of the morphological and biochemical analyses. Special attention was paid to the frequency of fungi occurring in multiple foci of the same system. In patients presented with ailments of the upper respiratory tract the presence of fungi, predominantly species of Candida genus was detected in different ontocenoses. In 1/4 of cases the fungi were found in 2 or 3 foci, which can induce systemic transmission, interfere with treatment and result in recurrent infections.  相似文献   
53.
We present the case of a 36-year-old female with severe heart failure which developed 20 years after irradiation due to Hodgkin's disease.  相似文献   
54.
BACKGROUND: Apoptosis is a therapeutic target for the elimination of cancer cells. As elevations in ceramide levels induce apoptosis, there is much excitement about the use of agents that elevate ceramide levels as novel chemotherapeutic agents. Ceramidases are enzymes involved in degradation of ceramide and inhibition of ceramidase has been proposed as a mechanism to increase ceramide levels. This study provides the first insight into the effect of B13, an inhibitor of acid ceramidase, on human prostate cancer cell lines and xenografts. METHODS: Cell death was evaluated by the trypan blue assay; apoptosis by the Apo2.7 apoptosis assay; and glutathione levels by HPLC. Tumors were irradiated with a dose of 5 Gy of X-rays (250 kVp, 15 mA, 2 Gy/min) and tumor volume was measured during the course of the experiment. At the conclusion of the experiment, tumor weight was determined and the tumors were evaluated histologically. RESULTS: B13 is an inducer of cell death, by apoptosis, in cultured prostate cancer cells. LNCaP and PC3 cells have different responsiveness to the enantiomers of B13. In LNCaP cells, the R enantiomer of B13 (10 microM) was significantly more effective than the S enantiomer at inducing cell death as determined by the trypan blue assay, culminating in approximately 90% cell death at 48 hr. In contrast, the same concentration of B13S induced <20% cell death at 48 hr. In PC3 cells, the S enantiomer was a more effective inducer of cell death, culminating in approximately 30% cell death, relative to 14% for B13R in this model. Evaluation of induction of apoptosis by the Apo2.7 mitochondrial assay confirmed that this induction of cell death was by apoptosis. Concurrent with induction of apoptosis, glutathione levels drop in response to B13. Specifically, B13R caused a significant drop in glutathione levels in LNCaP cells, culminating in a reduction to 40% control values at 48 hr. In PC3 cells, in contrast, the drop in glutathione levels was more dramatic, culminating in a drop to 12% control values in response to B13S at 48 hr. The effects of B13R, however, were not significantly different from control values. In in vivo studies using a model of xenografted androgen-insensitive prostate cancer, B13 sensitized the tumors to the effects of radiation, resulting in a significant reduction in tumor volume and weight after treatment with the combination of B13 and radiation. Microscopic evaluation of the tumors indicated that apoptosis was the primary mechanism of this effect. CONCLUSIONS: Targeting ceramide pathways may be a novel treatment strategy for hormone refractory prostate cancer.  相似文献   
55.
A case report of big lateral branchial cyst growing for 25 years is described. The diagnosis was based on ultrasonography with aspiration biopsy, computed tomography and histopathological findings. Successful surgical treatment was performed. Rarity of big size and long duration of the disease is emphasized.  相似文献   
56.
PURPOSE: The aim of this study was to compare the size and echotexture of the liver in psoriatic and healthy children. METHODS: In 70 psoriatic and 43 healthy children, longitudinal sonograms of the liver were obtained along standardized section planes defined by the anterior axillary line, medioclavicular line, and midline. The livers' size and echotexture were examined and compared between the study groups. RESULTS: The measurements of the liver along the 3 section planes were not significantly different between psoriatic and healthy children. Parenchymal liver echogenicity in psoriatic children was neither decreased nor increased. CONCLUSIONS: No abnormality in size or echotexture of the liver was found in the psoriatic children.  相似文献   
57.
The authors investigated the effect of pravastatin and fluvastatin on paraoxonase 1 (PON1) activity in plasma, liver, heart, and kidney, as well as on plasma platelet activating factor acetylhydrolase (PAF-AH) in the rat. The animals received pravastatin at doses of 4 and 40 mg/kg/d or fluvastatin at doses of 2 or 20 mg/kg/d for 3 weeks. Fluvastatin (20 mg/kg/d) reduced plasma PON1 activity toward paraoxon and phenyl acetate by 23.6% and 17.4%, respectively. The lower dose of this drug as well as both doses of pravastatin had no effect on plasma PON1. PON1 activity toward paraoxon in the liver of rats treated with 20 mg/kg/d fluvastatin was 27.5% lower than in the control group, and the activity toward phenyl acetate was reduced by 25.4% and 35.9% in rats receiving 2 and 20 mg/kg/d of this drug, respectively. Fluvastatin at 2 and 20 mg/kg/d also decreased cardiac PON1 by 31.3% and 27.3%, respectively. Both statins reduced PON1 activity in the renal cortex and medulla. Statins had no effect on plasma PAF-AH. It is concluded that fluvastatin reduces PON1 activity more efficiently than does pravastatin. Reducing effect on PON1 may negatively modulate atheroprotective potential of statins and may contribute to differences in antiatherosclerotic properties of different drugs in this group.  相似文献   
58.
7-{2-Hydroxy-3-[4-(2-phenoxyethyl)-piperazinyl-1-yl]-propyl}-1,3-di-methyl-3,7-dihydro-1H-purine-2,6-dione dihydrochloride (2), and several of its 8-alkylamino substituted derivatives (11-17) were synthesized and tested for electrocardiographic, antiarrhythmic and hypotensive activity. Also their alpha(1)- and alpha(2)-adrenoreceptor affinities were determined. It was found that compound 2, and its analogue 15 with 8-(2-morpholin-4-yl-ethylamino) substituent displayed a strong prophylactic antiarrhythmic activity in experimentally induced arrhythmia (LD50/ED50 = 54.9 and 55.0, respectively). The hypotensive activity was observed for 8-benzylamino (11) or 8-(pyridin-2-yl-methylamino) (12) analogues. All the new derivatives (11-17) and 2 showed a weak affinity for alpha1-(Ki = 0.225-1.400 microM) and alpha2-(Ki = 0.152-4.299 microM) receptors.  相似文献   
59.
Atrophy of the cerebral cortex in Huntington's disease is regionally heterogeneous and progressive, involving the entire cerebral mantle in terminal stages. Here, two areas (9 and 46) of the dorsolateral prefrontal cortex were analyzed in 11 late-stage (grades 3 or 4) Huntington's diseased patients and 8 normal control subjects. We used a 3-dimensional cell counting method to assess laminar cell density, number, and width. Reductions in overall cortical thickness in areas 9 (26%) and 46 (23%) were comparable. Area 9 exhibited loss of projection neurons in layers III (16%), V (31%), and VI (37%); these same layers were also reduced in width (25%, 34%, and 46%, respectively). In area 46, reductions in cortical width in layers II (18%) and VI (35%) were not accompanied by neuronal loss. Glial density was increased in deeper layers, reaching significance in layer VI (68%) of area 9 and in layer V (75%) of area 46; glial number was not altered. Thus, area 46 exhibited marked cortical thinning without apparent neuronal degeneration, whereas in area 9 neuronal loss was pronounced, consistent with an advanced phase of cortical pathology. Prominent involvement of corticothalamic neurons is discussed in the context of striatal loop circuitry and a possible pathologic cascade of cortical degeneration.  相似文献   
60.
BACKGROUND: Peridural fibrosis developing after lumbar discectomy may be responsible for as much as 20% of all Failed Back Surgery Syndrome. A variety of biological and non-biological materials have been used as a barrier to invasion of fibrous tissue into the vertebral canal. AIM: The purpose of this study was to evaluate the use of expanded polytetrafluoroethylene (ePTFE) surgical membrane (Gore-Tex membrane) to inhibit peridural fibrosis and reduce FBSS symptoms after lumbar discectomy. MATERIAL AND METHODS: In a prospective study we compared postoperative results in 20 patients who had an ePTFE membrane implanted during lumbar discectomy with the results in 20 patients in whom no material was implanted. The outcomes were evaluated using a questionnaire on activities of daily living according to the Low Back Outcome Score, pain grading scale -- Visual Analog Scale, assessment of Lasegue sign and MRI 18-24 months after the operation for all patients. RESULTS: The authors found no evident positive clinical and radiological effects of using ePTFE surgical membrane during lumbar discectomy. CONCLUSIONS: 1. It is impossible to prove that ePTFE membrane used during lumbar discectomy essentially prevents postoperative peridural scar formation. 2. The use of ePTFE membrane does not improve the outcome of the surgical treatment of lumbar disc herniation.  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