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   673篇
  免费   35篇
  国内免费   2篇
耳鼻咽喉   5篇
儿科学   44篇
妇产科学   14篇
基础医学   76篇
口腔科学   16篇
临床医学   38篇
内科学   144篇
皮肤病学   19篇
神经病学   53篇
特种医学   14篇
外科学   124篇
综合类   5篇
一般理论   1篇
预防医学   58篇
眼科学   29篇
药学   39篇
肿瘤学   31篇
  2023年   7篇
  2022年   19篇
  2021年   29篇
  2020年   15篇
  2019年   25篇
  2018年   20篇
  2017年   17篇
  2016年   19篇
  2015年   21篇
  2014年   36篇
  2013年   27篇
  2012年   39篇
  2011年   50篇
  2010年   23篇
  2009年   20篇
  2008年   29篇
  2007年   43篇
  2006年   34篇
  2005年   36篇
  2004年   32篇
  2003年   24篇
  2002年   37篇
  2001年   19篇
  2000年   16篇
  1999年   12篇
  1998年   1篇
  1997年   4篇
  1996年   5篇
  1995年   3篇
  1993年   4篇
  1992年   6篇
  1991年   7篇
  1990年   6篇
  1989年   1篇
  1988年   1篇
  1987年   5篇
  1986年   9篇
  1985年   2篇
  1984年   1篇
  1982年   1篇
  1978年   1篇
  1975年   1篇
  1974年   3篇
排序方式: 共有710条查询结果,搜索用时 31 毫秒
1.
Journal of Digital Imaging - Vertebral Compression Fracture (VCF) occurs when the vertebral body partially collapses under the action of compressive forces. Non-traumatic VCFs can be secondary to...  相似文献   
2.
Colorectal cancer is one of the best studied of all malignant diseases interms of genetics and/or molecular prognostic factors. These factors, and relationships with prognosis, may have important implications especially in the design of surgical and adjuvant chemo-radiotherapy options. However, the true prognostic significance of all known factors has yet to be realised. We have reviewed the literature with specific focus on the role of molecular markers involved in prognosis and the prediction of response to adjuvant treatment.  相似文献   
3.
A child with sickle cell anaemia developed a hepatic abscess, which was managed successfully by percutaneous drainage under ultrasound control. A history of attacks of pain dissimilar to usual vaso-occlusive crises should be treated with suspicion and investigated appropriately.  相似文献   
4.
1. Administration of bradykinin caused dose-dependent vasoconstriction in rat isolated perfused mesenteric arteries precontracted with noradrenaline. 2. The vasoconstrictor response was not mediated by BK1-bradykinin receptors. 3. Inhibition of cyclo-oxygenase with indomethacin, aspirin or meclofenamate abolished the vasoconstrictor effect of bradykinin, showing that a member of the arachidonic acid cascade may be involved. 4. Inhibitors of thromboxane synthesis (imidazole and UK 38485) did not affect or only reduced the bradykinin-induced vasoconstriction. 5. The endoperoxide H2/thromboxane A2 receptor antagonist SQ 29548 significantly reduced the vasoconstrictor effect of bradykinin, but did not affect the vasoconstrictor response to noradrenaline, adrenaline, vasopressin, 5-hydroxytryptamine or prostaglandins. 6. The eicosanoid(s) that mediate bradykinin-induced vasoconstriction appear to be synthesized outside the arterial endothelium. 7. The data suggest that the vasoconstrictor effect of bradykinin in the rat isolated mesenteric artery is mediated by vasoconstrictor arachidonic acid metabolites including the cyclic endoperoxides and/or the thromboxanes.  相似文献   
5.
Leukocyte arylsulphatase A (AS-A) was shown to be significantly high in newly-diagnosed breast cancer patients. Previous reports imply a connection between serum interleukin-6 (IL-6) and breast cancer, possibly through a modulation of enzymes involved in estrogen synthesis. Abnormal distribution of heparan sulphate proteoglycans (HSPGs) in malignant breast epithelial cells suggests that they play a key role in the regulation of cell growth. Estradiol is believed to be effective in modulating glycosaminoglycans (GAGs) and their depolymerizing enzymes. Therefore, in this study, attempts were made to evaluate the activity of leukocyte arylsulphatase A, serum interleukin-6, urinary GAGs and heparan sulphate (HS) in response to tamoxifen (TAM) therapy in mastectomised breast cancer patients. Thirty-four patients (aged 30-82 years) were administered TAM (20 mg twice daily). Blood and urine samples of each patient were collected three times (at the beginning, and in third and sixth month of TAM therapy), and biochemical parameters were measured. There was no difference between baseline leukocyte AS-A activity and that measured after three months. At the end of six months, enzyme activity was significantly higher than the former values (p=0.022), but within the reference intervals reported in the literature. Although this increase might imply a normalization, the duration of TAM therapy is not long enough to make a decision about either regression or aggravation of the disease. TAM did not have any effect on serum IL-6, urinary HS and GAG levels which may be due to insensitivity of these variables to TAM during the short period of therapy. Both urinary GAG and HS levels measured at sixth month exhibited a positive correlation with the baseline level of leukocyte AS-A (p=0.005 and 0.009, respectively), suggesting that positive responses to the drug might be seen in patients with low AS-A activity.  相似文献   
6.
HIV cross-sectional studies were conducted among high-risk populations in 9 countries of South America. Enzyme-linked immunosorbent assay screening and Western blot confirmatory testing were performed, and env heteroduplex mobility assay genotyping and DNA sequencing were performed on a subset of HIV-positive subjects. HIV prevalences were highest among men who have sex with men (MSM; 2.0%-27.8%) and were found to be associated with multiple partners, noninjection drug use (non-IDU), and sexually transmitted infections (STIs). By comparison, much lower prevalences were noted among female commercial sex workers (FCSWs; 0%-6.3%) and were associated mainly with a prior IDU and STI history. Env subtype B predominated among MSM throughout the region (more than 90% of strains), whereas env subtype F predominated among FCSWs in Argentina and male commercial sex workers in Uruguay (more than 50% of strains). A renewed effort in controlling STIs, especially among MSM groups, could significantly lessen the impact of the HIV epidemic in South America.  相似文献   
7.
Alveolar epithelial cells (AECs) may influence neighboring fibroblasts by the elaboration of prostaglandin E(2) (PGE(2)). This prostanoid can be synthesized via "constitutive" cyclooxygenase (COX)-1 and "inducible" COX-2 enzyme isoforms. We compared AECs isolated from wild-type (WT), COX-1 knockout (KO), and COX-2 KO mice to determine the contribution of COX isoforms to AEC PGE(2) synthesis and capacity for suppression of fibroblast proliferation in co-cultures. WT AECs constitutively expressed both COX-1 and COX-2 isoforms by immunoblot analysis. COX-1 KO cells and WT cells comparably augmented PGE(2) synthesis following incubation with lipopolysaccharide or interleukin-1, whereas COX-2 KO cells were unable to do so. Surprisingly, however, constitutive generation of PGE(2) was also dramatically reduced only in COX-2 KO cells. When co-cultured with WT murine lung fibroblasts, AECs from WT and COX-1 KO animals suppressed serum-induced fibroblast proliferation, whereas COX-2-deficient AECs caused a modest enhancement in fibroblast proliferation. These results indicate that PGE(2) synthetic capacity in AECs is predominantly COX-2-dependent under both basal and stimulated conditions. They also demonstrate conclusively that AECs can modulate fibroblast function by the elaboration of suppressive prostanoids. These alterations in AEC phenotype likely contribute to the propensity for pulmonary fibrosis observed in COX-2-deficient mice.  相似文献   
8.
BACKGROUND: Studies of immigrants represent an useful tool to determine the relative relevance of environmental vs genetic factors in causing the reported rapid increase of the prevalence of sensitization and allergic diseases. METHODS: A total of 152 Albanian migrants to Southern Italy responded to a questionnaire based on the European Community Respiratory Health Survey (ECRHS) and 139 of them underwent skin prick test, and 61 serological assays for total IgE and IgG antibodies against Toxoplasma gondii (TG), herpes simplex virus 1 (HSV-1), hepatitis A virus (HAV) and Helicobacter pylori (HP). RESULTS: Reported asthma was rare (2/152; 1.3%) and reported nasal allergies rather frequent (24/152; 15.8%). Sensitization to common inhalant allergens occurred in 27/139 (19.4%) subjects. The frequency of skin sensitization to pollen (P = 0.003) and that of hay fever (P = 0.004) increased with the time spent in Apulia. All the 61 sera had antibodies against HAV, 59/61 (96.7%) against HSV-1, 48/61 (78.7%) against HP and 34/61 (55.7%) against TG. The prevalence of skin sensitization and hay fever symptoms were correlated to the duration of residence in Southern Italy. CONCLUSIONS: Data presented indicate that Albanian migrants to Italy, in spite of the low prevalence of allergic diseases and sensitization in their country of origin, manifest with time an increasing prevalence of sensitization to local allergens and nasal symptoms after immigration to Italy. This would suggest a permanent role of allergen exposure and lifestyle factors in influencing the appearance of sensitization and symptoms of allergic diseases.  相似文献   
9.
Breast fat necrosis (BFN) is usually a benign inflammatory response to breast trauma. However, an extremely rare cause of fat necrosis is calciphylaxis, a calcification of small- and medium-sized arteries causing thrombosis and ischemia. It is classified into (A) uremic (B) nonuremic-induced calciphylaxis. Calciphylaxis has been reported to be encountered in different parts of the body. However, to the best of our knowledge there is only one case in the English literature of BFN 2ry to warfarin-induced calciphylaxis. We report a 65-year-old female, known case of atrial fibrillation on warfarin, presented with a left breast mass of 4-month duration. The mass was painful and progressively enlarging. Examination of the left breast showed 7 × 4 cm mass, spanning from 10-2 o'clock, free from surrounding structures, with preserved overlying skin. However, the mass was not visualized on mammogram. Ultrasound showed a left breast lobulated hypoechoic mass containing a hyperechoic component. Biopsy showed fat necrosis. After 1 month, she presented with ulceration of the overlying skin. After wide local excision, histopathology demonstrated a calciphylaxis-induced fat necrosis. Considering the patient's background, the diagnosis was BFN secondary to warfarin-induced calciphylaxis. Hence, the warfarin was shifted to Rivaroxaban, 6 months follow-up showed no evidence of recurrence. In conclusion, the rarity of nonuremic calciphylaxis is reflected on the delay of diagnosis in some of the reported cases and the lack of grading system used to guide the management of such difficult wounds. However, keeping a high index of suspicion is important whenever such wounds are encountered with presence of risk factors other than end-stage kidney disease.  相似文献   
10.
Age and Outcome After Severe Head Injury   总被引:5,自引:0,他引:5  
The authors analyzed the relationship between patient age and the final outcome in a series of 810 patients aged 14 years or older who were consecutively admitted between 1987 and 1996 after suffering a severe closed head injury. The most relevant clinico-radiological variables were prospectively collected in a Data Bank. Stratified and logistic regression analyses were performed in order to assess the influence of age on adverse outcome and the interaction between patient age and other prognostic indicators. Our results reaffirm that the adverse outcome rate increases steadily with age in severe head injured patients and that age effect on outcome is independent of other prognostic variables. The odds of having an adverse outcome increases significantly over 35 years of age being 10 times higher in patients older than 65 years as compared to those aged 15-25 years (reference age group). The adverse influence of an advanced age on the final outcome has not yet been satisfactorily explained but an older brain may have an impaired ability to recover after a pathological insult as compared to a younger one.  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