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   23946篇
  免费   1176篇
  国内免费   122篇
耳鼻咽喉   326篇
儿科学   365篇
妇产科学   498篇
基础医学   3020篇
口腔科学   672篇
临床医学   1767篇
内科学   6481篇
皮肤病学   262篇
神经病学   1823篇
特种医学   746篇
外科学   4134篇
综合类   103篇
一般理论   1篇
预防医学   737篇
眼科学   351篇
药学   1611篇
中国医学   45篇
肿瘤学   2302篇
  2022年   172篇
  2021年   402篇
  2020年   229篇
  2019年   260篇
  2018年   390篇
  2017年   301篇
  2016年   360篇
  2015年   375篇
  2014年   529篇
  2013年   656篇
  2012年   1015篇
  2011年   1120篇
  2010年   610篇
  2009年   545篇
  2008年   1060篇
  2007年   1146篇
  2006年   1074篇
  2005年   1014篇
  2004年   1032篇
  2003年   1006篇
  2002年   1059篇
  2001年   901篇
  2000年   932篇
  1999年   802篇
  1998年   295篇
  1997年   221篇
  1996年   208篇
  1995年   185篇
  1994年   164篇
  1993年   144篇
  1992年   602篇
  1991年   629篇
  1990年   534篇
  1989年   545篇
  1988年   525篇
  1987年   503篇
  1986年   430篇
  1985年   433篇
  1984年   318篇
  1983年   241篇
  1979年   233篇
  1978年   137篇
  1977年   138篇
  1974年   129篇
  1973年   123篇
  1972年   137篇
  1971年   127篇
  1970年   115篇
  1969年   137篇
  1967年   131篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The distribution of glucose-6-phosphate dehydrogenase (G6PD) activity has been studied by a copper ferrocyanide method in the adrenal cortex cells of a rat. The site of the G6PDH activity was close to the ribosome between the round mitochondria of zonas fasciculata and reticularis.  相似文献   
102.
103.
The risk of cerebral infarction (CI) in an individual is dependent on the interplay between genetic risk factors and environmental influences. Binding of thromboxane A2 (TXA2) to its receptor (TP) modulates thrombosis/hemostasis and plays a significant role in the pathogenesis of CI. The aim of the present study was to investigate the relationship between human TP gene single nucleotide polymorphisms (SNPs) and haplotypes and CI in a Japanese population. A genetic association study was performed in 194 CI patients and 365 non-CI subjects by specifically characterizing 6 SNPs in the human TP gene (rs2271875, rs768963, rs2238634, rs11085026, rs4523 and rs4806942). Analysis demonstrated that there were significant differences in the overall distribution of genotypes and dominant or recessive models of rs2271875 and rs768963 between the CI and the non-CI groups. Multiple logistic regression analysis revealed that the C allele of rs768963 was significantly associated with CI (p = 0.029), even after adjusting for confounding factors (odds ratio: 2.41). Further, the C-T-C haplotype of rs768963-rs2238634-rs4806942 was significantly more frequent in the CI group (23.0%) than in the non-CI group (17.7%). These results suggest that specific SNPs and haplotypes may have utility as genetic markers for the risk of CI and that TP or a neighboring gene is associated with the increased susceptibility to CI.  相似文献   
104.
Progressive multifocal leukoencephalopathy (PML) is caused by opportunistic infection of JC virus which belongs to Papovavirus, and presents with progressive demyelinating lesion in the central nervous system. PML was originally reported as a rare complication of hematologic disorders, but later greatly increased in number in association with acquired immunodeficeincy syndrome (AIDS). Original neuropathological features of PML consist of demyelination lacking inflammatory reaction or necrosis, accompanying oligodendroglial nuclear inclusions in the periphery of demyelination. The lesion is preferentially localized to gray-white junction of the cerebral hemisphere and manifests as characteristic demyelinating lesion, called scallopping. Detection of JC virus is essential for the final diagnosis of PML and is achieved via immunohistochemical detection of JC virus with antibodies raised against their components, ultrastructural demonstration of virions characteristic of JC virus, or detection with in-situ hybridization of the genome of JC virus. JC virus can replicate only in oligodendroglial cells, but astrocytes are frequently infected by the virus. The resume of immunological function through therapeutic intervention develops new pathology in PML, exhibiting severe inflammatory reaction with edema and necrosis. This new pathological feature is called immune reconstruction syndrome and clinically presents with severe progression in symptoms of the central nervous system. Nevertheless, treatment of PML is directed for the elimination of the viruses by host immune system. The modification of the above immune reconstruction syndrome is essential for successful outcome of such therapeutic trial.  相似文献   
105.
106.
OBJECTIVE: The risk of stroke caused by dislodgment of loose atheromatous plaque or mural emboli is increased by cross-clamping of the aorta. Some patients undergo descending thoracic aortic aneurysm repair with proximal aortic cross-clamping between the left common carotid artery and the left subclavian artery. The objective of this study was to determine the influence of proximal aortic cross-clamping in arteriosclerotic aneurysm or dissecting aneurysm repair. METHODS: Between May 1984 and May 2003, 81 patients underwent elective surgery for distal arch or descending aortic aneurysm repair with proximal aortic cross-clamping between the left common carotid artery and the left subclavian artery. To evaluate the influence of the proximal aortic cross-clamping, patients were divided into two groups: patients who had undergone arteriosclerotic aneurysm repair (group I, n=25) and patients who had undergone dissecting aneurysm repair (group II, n=56). RESULTS: Eight (9.9%) of the 81 patients had a stroke. Six strokes occurred in operations for arteriosclerotic aneurysm repair group I and two strokes occurred in operations for dissecting aneurysm repair group II (24 vs 3.6%; p=0.009). In-hospital mortality rates were 12% in group I and 8.9% in group II (p=0.70). Major postoperative complications included renal failure requiring hemodialysis (in 4.2% of the patients in group I and in 8.3% of the patients in group II, p=0.99) and pulmonary complication (in 20% of the patients in group I and in 16% of the patients in group II, p=0.67). CONCLUSION: Cross-clamping between head vessels should be avoided if at all possible when operating on patients who have arteriosclerotic descending thoracic aneurysms.  相似文献   
107.
Purpose  To describe three cases of mirror foot and to develop a new classification of the mirror feet with an emphasis on their treatment. Methods  Surgical treatment was performed on three patients with mirror foot. Mirror feet in the English literature were surveyed and cases found in PubMed as well as our three cases were classified according to a new classification that was an analogy of the mirror hand classification proposed by Al-Qattan et al. (J Hand Surg Br 23:534–536, 1998). Results  All three cases obtained satisfactory outcome after the treatment. In addition to these cases, 28 mirror feet were well described in the English literature, among which only seven cases have been documented for their treatment. All of the cases could be assigned to one of the categories of the proposed classification. Conclusion  Mirror foot is a very rare congenital deformity of the foot. We successfully treated three novel cases of mirror feet. A classification of the mirror feet proposed in this article was useful in order to understand its nature and obtain a guideline for its treatment.  相似文献   
108.
Five cases of retrograde thrombosis of former feeding arteries after removal of an arteriovenous malformation (AVM) are reported. The clinical features of these patients were studied and compared to those of 71 patients without this complication. The following characteristics were found to correlate with retrograde thrombosis: 1) advancing age of the patient; 2) large AVM size; and 3) markedly dilated and elongated feeders. It is suggested that the slow flow in the former feeding arteries that was observed immediately after AVM removal and pathological changes in these vessels due to long-standing hemodynamic stresses contributed to the development of retrograde thrombosis. Neurological manifestations related to retrograde thrombosis were noted in three of the five cases. Although infrequent, this complication should be considered as a serious possibility following removal of an AVM.  相似文献   
109.
A case of thrombasthenia (Glanzmann) associated with an intracerebral cavernous angioma in a 32-year-old woman is reported. Since her childhood, the patient had experienced a tendency to develop purpura following minor trauma. But she had not had major bleeding even during pregnancy and delivery. On April 4, 1987, she presented generalized convulsion. A high density mass in the right temporal lobe was demonstrated with CT scan. Carotid angiogram was normal except that the right anterior choroidal artery was stretched. Inhomogeneous signal intensities in T1- and T2-weighted MRI images were seen in the tumor locus. The clinical diagnosis was cavernous angioma which was complicated with intracerebral hemorrhage. The patient had a disorder of platelet function without thrombocytopenia. Her bleeding time was markedly prolonged. Because of this, we did not try surgical excision at first. During the 13-month observation period, however, intracerebral bleeding occurred 5 times. We decided to operate on the patient using fresh blood and platelet transfusion. The postoperative course was uneventful and pathological diagnosis confirmed cavernous angioma. We would like to emphasize possible pitfalls in treating cases of intracerebral angioma with thrombasthenia.  相似文献   
110.
The thymoma-prone rat of the BUF/Mna strain is a useful model for human thymoma. In this strain thymoma development is regulated by a single autosomal susceptible gene, Tsr-1. At pre-thymoma age, BUF/Mna rats have extremely large thyrauses, when compared to those of other strains of rats. Genetic studies in crosses between BUF/Mna rats with large thymuses and WKY/NCrj rats with small thymuses suggested the presence of a major autosomal gene, Ten-1 , which contributes to thymus enlargement in a backcross population. Linkage studies between Ten-1 and microsatellite markers in backcross rats of (WKY/NCrj×BUF/Mna)Fl×BUF/Mna have led to the localization of Ten-1 in chromosome 1. This result may provide an approach to clone Tsr-1 , which could be allelic to Ten-1.  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