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   112341篇
  免费   42340篇
  国内免费   445篇
耳鼻咽喉   2256篇
儿科学   4577篇
妇产科学   1088篇
基础医学   21536篇
口腔科学   5777篇
临床医学   15343篇
内科学   29273篇
皮肤病学   8681篇
神经病学   15809篇
特种医学   4463篇
外科学   18086篇
综合类   183篇
现状与发展   3篇
一般理论   31篇
预防医学   5511篇
眼科学   1936篇
药学   8858篇
中国医学   1438篇
肿瘤学   10277篇
  2024年   36篇
  2023年   311篇
  2022年   1028篇
  2021年   2754篇
  2020年   5634篇
  2019年   11542篇
  2018年   11036篇
  2017年   12086篇
  2016年   13203篇
  2015年   13625篇
  2014年   13740篇
  2013年   14491篇
  2012年   7733篇
  2011年   7382篇
  2010年   10756篇
  2009年   6802篇
  2008年   4317篇
  2007年   2880篇
  2006年   2539篇
  2005年   2269篇
  2004年   1920篇
  2003年   1740篇
  2002年   1646篇
  2001年   1248篇
  2000年   1149篇
  1999年   605篇
  1998年   203篇
  1997年   188篇
  1996年   133篇
  1995年   107篇
  1994年   107篇
  1993年   92篇
  1992年   137篇
  1991年   160篇
  1990年   137篇
  1989年   116篇
  1988年   109篇
  1987年   91篇
  1986年   89篇
  1985年   76篇
  1984年   52篇
  1983年   42篇
  1979年   58篇
  1978年   39篇
  1975年   57篇
  1974年   34篇
  1972年   41篇
  1971年   56篇
  1970年   35篇
  1968年   33篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
3-Monochloro-1,2-propanediol (MCPD) is a well-known by-product of acid-hydrolyzed soy sauce during its manufacturing process. MCPD has been reported genotoxic in vitro, and reproductive toxicity and carcinogenicity in rats. To evaluate the immunomodulatory effect of MCPD on murine splenocyte and macrophage in vitro, we investigated splenocyte blastogenesis by concanavalin A (Con A), anti-CD3, and lipopolyssacharide (LPS), the production of cytokines from splenocyte, and the activity of mouse peritoneal macrophages. There was a significant decrease in lymphocyte blastogenesis to Con A or anti-CD3 at subtoxic dose of MCPD. A significant decrease in splenocyte blastogenesis to LPS was also observed. The production level of interferon (IFN)-gamma on splenocyte culture with Con A was significantly reduced at the higher concentration than 1.0mM of MCPD. The levels of interleukin (IL)-4 and IL-10 were also decreased at high concentrations of MCPD. There was a significant decrease in production of nitric oxide (NO) by peritoneal macrophages treated with MCPD. MCPD also inhibits tumor necrosis factor (TNF)-alpha production of stimulated macrophages. These results indicate that MCPD might be able to reduce the functionality of lymphocytes and peritoneal macrophages in vitro.  相似文献   
92.
Fetal thrombosis of the dural sinus is an extremely rare congenital cerebrovascular condition that is potentially fatal. We report a case of dural sinus thrombosis diagnosed by prenatal ultrasonography and fetal magnetic resonance imaging (MRI) in the second trimester. The thrombosis showed partial resolution during pregnancy and resolved spontaneously after birth without neurological complications. This is the first report of spontaneous postnatal resolution, and may provide helpful information on the natural history and prenatal counseling of fetal thrombosis of the dural sinus.  相似文献   
93.
This study examined the relationship between psychological sense of community, social‐support networks, and care‐giver stress and satisfaction among firefighters. No significant gender differences were obtained, but zero‐order correlates demonstrated significant relationships among all four variables. In examining the mediating effects of social‐support satisfaction, partial mediation for psychological sense of community on care‐giver satisfaction was determined, as well as full mediation for psychological sense of community on care‐giver stress. Therefore, firefighters who are satisfied with the support they receive may experience less stress with their care giving than those who experience low levels of support satisfaction. Future studies should assess these relationships more extensively in other areas of civic responsibility among public‐service employees to delineate effective support avenues. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 121–126, 2004.  相似文献   
94.
A 3.5‐year‐old intact male American Pit Bull was presented because of urinary incontinence and dysuria. Constipation, followed by diarrhoea, ocular disturbances and finally regurgitation developed over the next 4 years. Autonomic dysfunction was evidenced by clinical presentation, as well as positive ophthalmic pilocarpine test and subnormal Schirmer tear test. Diagnosis, however, was established through histopathological and immunohistochemical examination. Lesions attributable to inflammatory degenerative neuropathy of the autonomic ganglia, which represents one of the various types of human autonomic failure, were detected.  相似文献   
95.
Hemorrhagic disseminated intravascular coagulation (DIC) associated with the presence of underlying advanced or metastatic tumors are often difficult to control by conventional methods. We report the use of recombinant activated factor VII (rFVIIa) in patients with cancer and bleeding secondary to DIC. A total of 18 patients with cancer met pre-defined criteria for DIC. All patients had failed to respond to transfusion with blood products and treatment of the underlying malignancy prior to the introduction of rFVIIa. The median laboratory data at the time of treatment with rFVIIa were as follows: hemoglobin, 7.7 g/dl; platelets, 54 x 10(9)/l; prothrombin time, 21 s; activated partial thromboplastin time, 41 s fibrinogen, 83 mg/dl; D-dimer, 17 microg/ml; and antithrombin, 32%. The dose of rFVIIa was 90 microg/kg and the median number of doses administered was 5 (range, 3-10). Serial measurements of coagulation parameters were obtained at frequent intervals during treatment with rFVIIa. Of the 18 patients, 15 responded with cessation of bleeding and improvement in coagulation data. The prothrombin time and activated partial thromboplastin time normalized in all responding patients within 24 h of treatment. The median fibrinogen was 214 mg/dl while the median D-dimer was 6 microg/dl at 48 h following the administration of rFVIIa. No thromboembolic complications were observed following rFVIIa. Our data provide evidence that rFVIIa can be used successfully to control the hemorrhagic episodes associated with DIC. Although this type of treatment appears to be safe, close monitoring of the patients is warranted.  相似文献   
96.
Childhood psoriasis is a disease with manifold clinical presentations which can make the correct diagnosis sometimes difficult. In a female infant, slightly itching, erythematous papules and plaques with discrete scaling spread over large parts of the integument starting from age three months. Histological examination supported the diagnosis of exanthematous infantile psoriasis. Topical treatment with dithranol in petrolatum led to slow clearance of the skin lesions.  相似文献   
97.
The etiology of epidermolysis bullosa acquisita (EBA) is unknown. EBA may be associated with other autoim‐mune systemic diseases; it also has been described in connection with different malignant tumors, showing complete remission after successful treatment of the tumor.In such cases, EBA may be regarded as a paraneo‐plastic dermatosis. We detected a highly differentiated neuroendocrine pancreatic cancer in a 78‐year‐old woman with EBA. Even thought her tumor was completely removed and the patient has been disease‐free for over seven years, a complete regression of her autoimmune bullous dermatosis could not be induced. By using intravenous immunoglobulins in combination with mycophenolate mofetil, further blister formation could be ameliorated.  相似文献   
98.
AIMS: The glutamate decarboxylase gene (GAD2) encodes GAD65, an enzyme catalysing the production of the gamma-aminobutyric acid (GABA) which interacts with neuropeptide Y to stimulate food intake. It has been suggested that in pancreatic islets, GABA serves as a functional regulator of pancreatic hormone release. Conflicting results have been reported concerning the potential impact of GAD2 variation on estimates of energy metabolism. The aim of this study was to elucidate potential associations between the GAD2-243A-->G polymorphism and levels of body mass index (BMI) and estimates of glycaemia. METHODS: Using high-throughput chip-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, the GAD2-243A-->G (rs2236418) polymorphism was genotyped in a population-based sample (Inter99) of 5857 middle-aged, unrelated Danish White subjects. RESULTS: The G-allele was associated with modestly lower BMI (P = 0.01). In a case-control study of obesity, the G-allele frequency in 2582 participants with BMI < 25 kg/m2 was 19.5% (18.4-20.6) compared with 17.1% (15.5-18.8) in 968 participants having BMI > or = 30 kg/m2 (P = 0.03), odds ratio 0.9 (0.7-1.0). Of the 5857 subjects, GG carriers had lower fasting plasma glucose levels (mmol/l) [AA (n = 3859) 5.6 +/- 0.8; AG (n = 1792) 5.5 +/- 0.8; GG (n = 206) 5.5 +/- 0.8, P = 0.008] and lower 30-min oral glucose tolerance test (OGTT)-related plasma glucose levels (AA 8.7 +/- 1.9; AG 8.6 +/- 1.9; GG 8.6 +/- 2.0, P = 0.04), adjusted for sex, age and BMI. Analysing subjects who were both normoglycaemic and glucose tolerant (n = 4431) GG carriers still had lower fasting plasma glucose concentrations: AA (n = 2895) 5.3 +/- 0.4; AG (n = 1383) 5.3 +/- 0.4; GG (n = 153) 5.2 +/- 0.4 (P = 9.10(-5)). CONCLUSION: The present study suggests that the GAD2-243A-->G polymorphism in a population of middle-aged White people associates with a modest reduction in BMI and fasting and OGTT-related plasma glucose levels.  相似文献   
99.
100.
We consider the problem of detection of modifier genes that lead to variations in a disease‐related continuous variable (DRCV), such as the age of onset or a measure of disease severity, in a strategy of candidate genes. We propose a novel method, the ordered transmission disequilibrium test (OTDT), to test for a relation between the clinical heterogeneity expressed by a DRCV and marker genotypes of a candidate gene. The OTDT applies to trio families with one patients and his parents, all three genotyped at a bi‐allelic marker M. The OTDT aims to find a critical value of the DRCV which separates the sample of families in two subsamples in which the transmission rates are significantly different. We investigate the power of the method by simulations under various genetic models and covariate distributions and compare it with a linear regression analysis. Genet. Epidemiol. 2008. ©2008 Wiley‐Liss, Inc.  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