全文获取类型
收费全文 | 8006篇 |
免费 | 438篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 122篇 |
妇产科学 | 87篇 |
基础医学 | 885篇 |
口腔科学 | 285篇 |
临床医学 | 447篇 |
内科学 | 1925篇 |
皮肤病学 | 106篇 |
神经病学 | 965篇 |
特种医学 | 363篇 |
外科学 | 1509篇 |
综合类 | 18篇 |
预防医学 | 267篇 |
眼科学 | 98篇 |
药学 | 531篇 |
中国医学 | 11篇 |
肿瘤学 | 790篇 |
出版年
2023年 | 64篇 |
2022年 | 88篇 |
2021年 | 149篇 |
2020年 | 96篇 |
2019年 | 116篇 |
2018年 | 160篇 |
2017年 | 118篇 |
2016年 | 154篇 |
2015年 | 141篇 |
2014年 | 184篇 |
2013年 | 214篇 |
2012年 | 385篇 |
2011年 | 404篇 |
2010年 | 243篇 |
2009年 | 191篇 |
2008年 | 335篇 |
2007年 | 410篇 |
2006年 | 372篇 |
2005年 | 361篇 |
2004年 | 320篇 |
2003年 | 309篇 |
2002年 | 327篇 |
2001年 | 325篇 |
2000年 | 305篇 |
1999年 | 298篇 |
1998年 | 92篇 |
1997年 | 81篇 |
1996年 | 73篇 |
1995年 | 63篇 |
1994年 | 57篇 |
1993年 | 47篇 |
1992年 | 186篇 |
1991年 | 182篇 |
1990年 | 156篇 |
1989年 | 164篇 |
1988年 | 149篇 |
1987年 | 149篇 |
1986年 | 161篇 |
1985年 | 128篇 |
1984年 | 74篇 |
1983年 | 78篇 |
1979年 | 60篇 |
1978年 | 42篇 |
1977年 | 41篇 |
1974年 | 34篇 |
1973年 | 37篇 |
1971年 | 27篇 |
1970年 | 35篇 |
1969年 | 35篇 |
1968年 | 27篇 |
排序方式: 共有8473条查询结果,搜索用时 15 毫秒
91.
92.
Between 1981 and 1996, the authors performed reconstructions with vascularized free flaps in four patients with congenital arteriovenous malformations of the hand. This series included one man and three women, whose ages at the time of surgery ranged from 20 to 57 years, with an average of 41 years. All were categorized as fast-flow type B malformations. The locations of the arteriovenous malformations were the thumb only, thumb to palm, index to palm, and thumb and index to palm. In all cases, free vascularized flaps (two dorsalis pedis, one wrap-around, and one peroneal) were utilized to replace the resected abnormal skin lesions. Follow-up ranged from 1 year to 18 years and 9 months, with an average of 7 years. All flaps survived with no complications, and all patients were relieved of their preoperative symptoms. One patient unfortunately committed suicide for unknown reasons. The authors recommend that complete resection be carried out whenever possible. When skin is involved, repair should be carried out with a free flap. Based on the good results achieved in the case followed-up for over 18 years, vascularized free flaps proved very useful for the treatment of arteriovenous malformations. 相似文献
93.
Guo RJ; Wang Y; Kaneko E; Wang DY; Arai H; Hanai H; Takenoshita S; Hagiwara K; Harris CC; Sugimura H 《Carcinogenesis》1998,19(9):1539-1544
Mutations in the transforming growth factor beta type II receptor
(TGFbetaRII) gene have been detected in several human cancer types
exhibiting microsatellite instability. Using intron primers previously
reported for examination of the entire coding region of the TGFbetaRII
gene, 29 sporadic gastric cancers were screened with non-radioactive single
strand conformation polymorphism and subsequent DNA sequencing analysis.
Mutations of the TGFbetaRII gene were detected in three out of 29 tumors
(10%). Two cases showed deletions in a polyadenine tract in both alleles
and was positively associated with replication error. One case had an
insertion of GA dinucleotide sequence in one allele. Mutations of the
TGFbetaRII gene were restricted to exon 3 and other coding regions were not
affected. Loss of heterozygosity was detected by analyzing a polymorphic
site in intron 2. Three out of nine (33%) informative cases, which were all
of intestinal type and advanced cases, showed loss of heterozygosity but
neither TGFbetaRII mutation nor replication error was found in these cases.
Immunoreactivity of TGFbetaRII in tumor tissues was reduced to a different
extent in the gastric cancer with genetically abnormal transforming growth
factor. Although the numbers studied are small, homozygous (A)10 deletion
or loss of heterozygosity of TGFbetaRII is involved in tumorigenesis and
progression of at least some part of sporadic gastric cancer.
相似文献
94.
Hiroshi Arai Takaaki Beppu Tukasa Wada Yuuki Yoshida Yoshitaka Kubo Michiyasu Suzuki Akira Ogawa 《Brain tumor pathology》1998,15(1):37-40
We investigated factors of the early recurrence and malignant transformation of histologically benign meningiomas using immunohistochemistry
for MIB-1 positive indices (PI) and p53 protein expression, a flow cytometric DNA analysis, and the examination of numerical
chromosomal aberrations detected by fluorescence in situ hybridization using an α-satellite DNA probe and abcr gene locus-specific probe. Twenty-six meningiomas of 23 patients were classified into two groups: the 3 patients in whom
a recurrence was defined within two years after initial surgery and who showed histologically malignant features were classified
as the early recurrent group, and the other 20 patients in whom recurrence did not develop during the same period were classified
as the nonrecurrent group. DNA aneuploidy was observed in 40% of the nonrecurrent patients and in 67% of the early recurrent
patients. Loss of chromosome 22 was the most common numerical aberration, but the aberrations characteristic of early recurrent
meningiomas were not detected. The MIB-1 PI values of the early recurrent meningiomas were higher than those of nonrecurrent
meningiomas, suggesting that MIB-1 PI is very important for biological and histopathological analyses and prediction of the
future recurrence of meningiomas. 相似文献
95.
We describe the technical benefits of the dual-access technique for venous stenting in high-grade stenosis. Stents were implanted
successfully with this technique in all patients, although the preceding transfemoral interventions had failed. The dual-access
technique is useful to facilitate the intervention when the stenoses are too severe to place the stent through just a single
access point.
Received: 21 October 1998; Revised: 23 February 1999; Accepted: 3 May 1999 相似文献
96.
Arai H Ishiguro K Ohno H Moriyama M Itoh N Okamura N Matsui T Morikawa Y Horikawa E Kohno H Sasaki H Imahori K 《Experimental neurology》2000,166(1):201-203
Cerebrospinal fluid (CSF) tau protein phosphorylated at both Thr231 and Ser235 sites (CSF/phospho-tau(231-235)) and total tau (CSF/total-tau) were quantified by sandwich ELISA in 20 patients with mild cognitive impairment (MCI) who eventually developed AD on follow-up as well as seven memory complainers with no objective memory loss. 13/20 (65%) of the MCI patients had high CSF/total-tau and detectable levels of CSF/phospho-tau(231-235), whereas these markers were low and under a detectable level in all of the memory complainers. Although either a total-tau, phospho-tau measurement or a combination of these can help in predicting if MCI will develop AD, our results suggest that the pathogenic steps of AD may be at the stage that finally leads to an accumulation of abnormally phosphorylated tau and neuron death, at least in some brain areas, when MCI patients present with the earliest detectable clinical symptoms of dementia. 相似文献
97.
During development in the chick embryo, luteinizing hormone-releasing hormone (LHRH) neurons migrate along the olfactory nerve from the olfactory epithelium to the forebrain. At embryonic day 5.5 (E5.5) to E6.0, the majority of LHRH neurons begin to enter the medial forebrain and then course dorsocaudally along the forebrain substance just beneath the pia matter in association with the somatostatin (SST)-positive fibers, which branch medially from the SST-positive olfactory nerve. By E6.5, the neurons and SST-positive medial branch of the olfactory nerve have proceeded toward the septal area. Intense immunoreactivity for the polysialylated form of neural cell adhesion molecule (PSA-NCAM) on both the LHRH neurons and the SST-positive fibers during this period suggests that this less adhesive form of NCAM is involved in the migratory process. This possibility was examined by using a polysialic acid (PSA)-specific endoneuraminidase. PSA removal did not alter the behavior or appearance of the SST-positive olfactory fibers within the migration pathway. However, it induced a significant deviation of migrating LHRH neurons from the regular path in the forebrain. The effect of PSA removal is more likely to involve changes in the interaction of the migrating neurons with a subset of the SST-positive olfactory fibers and/or other elements in the forebrain rather than an alteration in the pattern of their axonal substrate. On the basis of these results, it is suggested that PSA contributes to the specific pattern of LHRH neuronal migration in the forebrain by limiting interaction of these LHRH neurons with their surrounding environment. 相似文献
98.
Fast gradient-echo sequences that use an echo-train readout are becoming more widely used, particularly for imaging the heart. An important issue for these sequences involves determining the optimal duration for the echo-train readout. In normal volunteer scans and theoretically the echo-train readout duration was varied from 2.4 to 32.8 msec. Myocardial signal-to-noise ratio (SNR), myocardium-tag signal difference-to-noise ratio (SDNR), flow artifact-to-noise ratio (FNR), and geometric distortion were measured and/or calculated. Our results showed that to obtain high SNR, SDNR, and data acquisition efficiency while minimizing FNR and geometric distortion, the readout duration should be 10-15 msec at 1.5 T. 相似文献
99.
Subcortical meningioma, which has been reported as meningioma without dural attachment, a cerebral subcortical lesion, is extremely rare. Very few findings of radiological examination of subcortical meningioma have been described. Pre-operative differentiation of this lesion is generally difficult. We characterize the peritum oural oedema adjacent to the meningioma in this region, and we suggest that radiological findings of peritum oural oedema contribute to differential diagnosis of subcortical meningiomas. 相似文献
100.
Shinozuka N Koyama I Arai T Numajiri Y Watanabe T Nagashima N Matsumoto T Ohata M Anzai H Omoto R 《American journal of surgery》2000,179(1):42-45
BACKGROUND: Homologous blood transfusion (HBT) has the risk of an immunosuppressive effect and may adversely affect the prognosis of patients with carcinomas. Autologous blood transfusion (ABT) has not yet become a standard procedure in gastroenteric cancer surgery. We investigated the usefulness and problems of ABT combined with the use of recombinant human erythropoietin (rh-EPO). METHODS: An evaluation of autologous blood transfusion (ABT) combined with recombinant human erythropoietin (rh-EPO) treatment was conducted in 46 patients with hepatocellular carcinoma undergoing hepatectomy. Preoperative autologous blood donation (ABD) was accomplished for 25 of the 46 patients. The preoperative changes in hemoglobin and hematocrit in relation to route of administration of erythropoietin were studied. In addition, intraoperative blood requirements and the postoperative complications for patients who predonated were compared with those of patients who underwent surgery without autologous predonation. RESULTS: The proportion of patients not requiring additional homologous blood transfusions (HBT) during operation was significantly higher in the ABD group than in the non-ABD group (88% versus 38%). The incidence of postoperative complications was significantly higher in patients receiving HBT than in nontransfused patients and in those receiving ABT. CONCLUSIONS: Preoperative autologous blood donation in combination with rh-EPO therapy markedly reduced the requirement for homologous blood transfusion during surgery in patients with hepatocellular carcinoma having hepatectomy. 相似文献