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   7023篇
  免费   419篇
  国内免费   38篇
耳鼻咽喉   79篇
儿科学   249篇
妇产科学   80篇
基础医学   1209篇
口腔科学   107篇
临床医学   529篇
内科学   1646篇
皮肤病学   187篇
神经病学   744篇
特种医学   258篇
外科学   591篇
综合类   50篇
预防医学   388篇
眼科学   160篇
药学   557篇
中国医学   12篇
肿瘤学   634篇
  2024年   4篇
  2023年   72篇
  2022年   119篇
  2021年   162篇
  2020年   93篇
  2019年   145篇
  2018年   182篇
  2017年   147篇
  2016年   150篇
  2015年   129篇
  2014年   224篇
  2013年   304篇
  2012年   480篇
  2011年   477篇
  2010年   272篇
  2009年   299篇
  2008年   458篇
  2007年   529篇
  2006年   469篇
  2005年   500篇
  2004年   501篇
  2003年   464篇
  2002年   473篇
  2001年   59篇
  2000年   34篇
  1999年   59篇
  1998年   89篇
  1997年   80篇
  1996年   70篇
  1995年   61篇
  1994年   39篇
  1993年   61篇
  1992年   46篇
  1991年   36篇
  1990年   28篇
  1989年   23篇
  1988年   18篇
  1987年   14篇
  1986年   7篇
  1985年   8篇
  1984年   13篇
  1983年   12篇
  1982年   13篇
  1981年   7篇
  1980年   13篇
  1979年   7篇
  1978年   3篇
  1977年   4篇
  1975年   4篇
  1973年   5篇
排序方式: 共有7480条查询结果,搜索用时 15 毫秒
81.
We report a malformed female infant withde novo interstitial deletion of 4q[46,XX,del(4)(q27q28.2)]. The MN blood type analysis of the family members showed that the patient had an intact blood group-MN locus. The locus of the gene responsible for the MN antigen activity is confined to a 4q28.2–4q31.1 segment on the basis of the result of this patient and the previous mapping data.  相似文献   
82.
To evaluate the therapeutic potential of FX0685, a new triazole antifungal agent, for the treatment of opportunistic fungal infections, particularly systemic candidiasis and aspergillosis, in vitro and in vivo studies were performed using fluconazole (FLC), itraconazole (ITC) and/or amphotericin B (AMB) as reference drugs. A preliminary in vitro study showed that the antifungal activity of FX0685 against FLC-susceptible Candida albicans, several non-C. albicans Candida species and Cryptococcus neoformans was superior to that of FLC and comparable or superior to those of ITC and AMB, while the anti-Aspergillus fumigatus activity of FX0685 was to varying degrees lower than that of ITC. FX0685 appeared to be comparable to FLC and ITC in the treatment of murine systemic C. albicans and pulmonary A. fumigatus infection, respectively. The biological property of FX0685 was characterized by its potent in vitro and in vivo activity against FLC-resistant C. albicans. Part of this unique property was explained by the finding that it retained potent inhibitory activity against those CYP51 molecules in which amino acid substitutions confer a phenotype of resistance to FLC and some other azole derivatives. All of these results lead to the possibility that FX0685 may be a potential antifungal drug candidate for the treatment of various clinical forms of systemic candidiasis, including those caused by FLC-resistant C. albicans, as well as for the treatment of pulmonary aspergillosis.  相似文献   
83.
84.
85.
CA19-9 widely used as a tumor marker of the pancreas and a bile duct. There are a number of reports which describes the measured value discrepancies between RIA and non-RIA kits. RIA results also have shown lack of the linearity over 70 U/ml when the samples are diluted. The pH condition at assay reaction for RIA had been suggested as the major reason, it has been denied by the results from the same pH condition at assay reaction used by COBAS CORE CA19-9 EIA II. On the other hand, the lack of RIA antibody titer is indicated for the discordant results by changing the sample volume to reagent volume ratio in the reaction. Our further investigation also indicates that the specific Lewis blood type, i.e. Le (a-b+), shows the linearity issues by RIA. The discrepancies are not caused by the reaction pH, but the amount of the antibody used in the RIA kit is closely associated. Considering the CA19-9 antibody nature used in RIA kit, which covers broad molecular range, users need to pay more attention to setting up each laboratory's measuring range.  相似文献   
86.
Heparin-induced thrombocytopenia(HIT) due to immunological mechanisms is known as an important adverse reaction to heparin treatment, and heparin treatment should be applied while keeping in mind the risk of onset of HIT 5-14 days after the initiation of heparin. The presence of HIT had not been fully recognized in clinical practice in Japan despite the management of HIT being well confirmed in Western countries. Recognition of HIT has increased since argatroban, a direct thrombin inhibitor, obtained the approval of the FDA for prevention and treatment of HIT. Although the incidence of HIT in Japan has not yet been clarified, there is some evidence that HIT is encountered in critically ill patients undergoing heparin anticoagulation. Clinical diagnosis of HIT is performed by means of thrombocytopenia of a drop of 50% or 100 x 10(30/microl for 5 -14 days after starting heparin treatment. Confirmatory laboratory tests examine whether the patients have antibodies against heparin/PF4 complexes or not. Two assay tests for detecting heparin/PF4 complex antibodies are available in Japan. As a functional test, the heparin-induced platelet aggregation method is easily performed and the result is obtained in a short time. The result of the test has, however, been misleading due to the selection of donors. Low platelet activity of the donors on the addition of heparin induces a negative response in spite of positive antibodies in the sample. Before testing samples, it is important to check heparin reactivity of the donor's platelets. Enzyme immunoassay detecting the antibodies is available as a commercial kit. Sensitivity obtained by enzyme immunoassay is very high and often introduces false-positives. Careful attention to interpretation of the result is required. Treatment of HIT should be started at the time of recognition of thrombocytopenia while antibody testing for HIT is performed. As an alternative anticoagulant to heparin, argatroban should immediately be applied to avoid complication of thrombosis. Thrombocytopenia and hypercoagulability quickly recover to the preheparin level by the appropriate use of argatroban.  相似文献   
87.
Citrin is a mitochondrial aspartate glutamate carrier primarily expressed in the liver, heart, and kidney. We found that adult-onset type II citrullinemia is caused by mutations in the SLC25A13 gene that encodes for citrin. In this report, we describe the frequency of SLC25A13 mutations, the roles of citrin as a member of the urea cycle and as a member of the malate-aspartate shuttle, the relationship between its functions and symptoms of citrin deficiency, and therapeutic issues.  相似文献   
88.
Summary We have examined the nonparallel changes in tampanic membrane temperatures (T ty) from the two ears in response to various changes in body and head positions. Upon assuming a lateral recumbent position, the T ty on the lower side increased while that on the upper side decreased. Pressure application over a wide area of the lateral chest only caused inconsistent and obscure asymmetric changes in T ty. A lateral flexion of the head with the subject sitting upright and a rotation of the head to the side in a supine position induced an increase in the T ty on the lower side compared to that on the upper side. The temperature and blood flow of the forehead often decreased on the lower side and increased on the upper side, although such responses were not always concomitant with the asymmetric changes in T ty. A dorsal flexion of the head with the subject in a reclining position caused a slight increase in the T ty, whereas raising the head upright induced a slight decrease in them. Two additional experiments were carried out with single photon emission computed tomography using 99mTc-hexamethylpropyleneamine oxime as tracer, and a slight, relative decrease in counts was noted in the right hemisphere during rotation of the head to the right. These results would strongly suggest that unilateral increases and decreases in T ty could have been caused by one-sided decreases and increases, respectively, in blood flow to the brain and/or the tympanic membrane, induced by a vasomotor reflex involving vestibular stimulation.  相似文献   
89.
We have studied three children with de novo terminal deletion of the long arm of chromosome 1 (46,XX,del(1)(q43)). They all have minor anomalies and neurological signs (severe psychomotor developmental delay, generalized hypotonia, and seizures) that have been described previously. In addition, all of these three patients have autistic-like behavior. They avoid eye contact, show no interest in people, express little emotion, and repeat stereotypic movements such as head nodding and purposeless finger manipulation. They also spend excessive time in making unusual sounds consisting of a high-pitched shrill cry with little intonation in infancy and a harsh, strained, and glottal stridency in later life. They make no labial, lingual, or nasal sounds. We suggest that these observations may be unique clinical manifestations of certain terminal 1q deletions.  相似文献   
90.
A case of adrenal pheochromocytoma Is reported characterized by polygonal basophilic granular cells of benign type, plump eosinophilic granular cells of transitional type, and spindle-shaped cells of malignant type. In the primary tumor the neoplastic cells of each type revealed a distinctive topographical distribution. All gradations between the latter two varieties of cells were found, especially in the vicinity of the transitional cell area. Multiple metastases were present in the liver and lungs, where only anaplastic spindle-shaped cells could be found. Ultrastructurally, the benign cells contained predominantly large, rather light, secretory granules with a coarsely granulated core. In the malignant cells, the number, size, and intensity of granules varied considerably from cell to cell or even within a single cell. In general, the malignant cells had a higher frequency of smaller granules with electron-dense homogeneous cores. Moderate amounts of noradrenalin but not significant dopamine or adrenalin could be demonstrated from a metastatic nodule In liver. We postulate that this adrenal medullary pheochromocytoma was benign originally and underwent malignant transformation shortly before the patient's death. This is based upon the patient's clinical features and the peculiar structures of the primary tumor.  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