全文获取类型
收费全文 | 14651篇 |
免费 | 608篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 144篇 |
儿科学 | 451篇 |
妇产科学 | 143篇 |
基础医学 | 1942篇 |
口腔科学 | 292篇 |
临床医学 | 983篇 |
内科学 | 3962篇 |
皮肤病学 | 322篇 |
神经病学 | 998篇 |
特种医学 | 520篇 |
外科学 | 2238篇 |
综合类 | 38篇 |
一般理论 | 1篇 |
预防医学 | 470篇 |
眼科学 | 217篇 |
药学 | 1041篇 |
中国医学 | 34篇 |
肿瘤学 | 1534篇 |
出版年
2023年 | 72篇 |
2022年 | 169篇 |
2021年 | 261篇 |
2020年 | 187篇 |
2019年 | 191篇 |
2018年 | 274篇 |
2017年 | 240篇 |
2016年 | 257篇 |
2015年 | 259篇 |
2014年 | 334篇 |
2013年 | 415篇 |
2012年 | 650篇 |
2011年 | 795篇 |
2010年 | 470篇 |
2009年 | 420篇 |
2008年 | 736篇 |
2007年 | 762篇 |
2006年 | 731篇 |
2005年 | 811篇 |
2004年 | 814篇 |
2003年 | 743篇 |
2002年 | 711篇 |
2001年 | 334篇 |
2000年 | 334篇 |
1999年 | 303篇 |
1998年 | 182篇 |
1997年 | 148篇 |
1996年 | 148篇 |
1995年 | 139篇 |
1994年 | 134篇 |
1993年 | 144篇 |
1992年 | 302篇 |
1991年 | 256篇 |
1990年 | 221篇 |
1989年 | 286篇 |
1988年 | 251篇 |
1987年 | 234篇 |
1986年 | 235篇 |
1985年 | 206篇 |
1984年 | 152篇 |
1983年 | 112篇 |
1982年 | 71篇 |
1981年 | 57篇 |
1980年 | 48篇 |
1979年 | 92篇 |
1978年 | 71篇 |
1977年 | 57篇 |
1971年 | 47篇 |
1969年 | 48篇 |
1968年 | 47篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Noriko Kimura Mika Watanabe Tsuneo Ookuma Wakako Miura Takao Noshiro Yukio Miura Hiroshi Nagura 《Endocrine pathology》1994,5(3):178-182
Pheochromocytoma usually shows prominent nuclear atypia, but the presence of such atypical cells is known to be an unreliable
predictor of malignancy. DNA ploidy of pheochromocytomas has been analyzed by flow cytometry or photospectrometry on paraffinem-bedded
tissue, but the results were controversial. We performed DNA analysis on cytology specimens of 11 pheochromocytomas using
an image analysis system. All tumors had a mixed pattern of a large population of diploid cells and a small population of
polyploid cells. DNA content correlated with nuclear size, and larger cells had more DNA content. Such larger tumor cells
had polyploid nuclei, such as 4 C, 8 C, 16 C, and 32 C, in both malignant and benign pheochromocytomas. The larger polyploid
nuclei may result from difficulty of duplication at the mitotic phase of the cell cycle. 相似文献
62.
Tadashi Yasuda Hirokazu Imai Yasushi Nakamoto Akira B. Miura Shiegki Inomata 《Virchows Archiv : an international journal of pathology》1992,421(4):297-303
Summary The pathogenesis of the nodular lesion in diabetic glomerulosclerosis is described in association with fibrils. Thirteen diabetic patients with glomerular nodular lesions and 9 diabetics without the nodules were examined by electron microscopy using periodic acid-thio-carbohydrazide-silver proteinate staining. In cases of nodular glomerulosclerosis, abundant fibrillar structures mixed with electron-dense material were detected within the nodule and the mesangial matrix. They were also occasionally observed along the subendothelial space of the glomerular capillary walls. On the cross-section, these fibrils, including the lucent periphery, were 34 nm wide. Immunohistologically, collagen V and collagen VI were detected in nodular lesions. In contrast, in cases of the diffuse type of glomerulosclerosis, the widened mesangium was composed of dense material, which resembled the original mesangial matrix. The above fibrils were not detected in the mesangium. These findings suggest that the accumulation of the peculiar fibrils in the glomerular mesangium is a major pathogenic factor in the formation of Kimmelstiel-Wilson nodules. 相似文献
63.
Kazuya Yamagata Toshiaki Hanafusa Hirumn Nakajima Masaharu Sada Hiroshi Amemiya Koji Tomita Jun-Ichiro Miyagawa Tamlo Noguchi Takebiko Tanaka Norio Kono Seiichiro Tarui 《Tissue antigens》1991,38(1):107-110
ABSTRACT: Human leukocyte antigen (HLA) genes are candidates for susceptibility genes in insulin-dependent diabetes mellitus (IDDM). Recently, the association of DR and DQ with IDDM has been reported, but the role of HLA-DP genes remains uncertain. To address the question, we analyzed the DPB1 gene of 20 Japanese IDDM patients and 30 control subjects using a combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis (PCR-RFLP method). DPB1*0501 was the most frequent allele both in Japanese patients and control subjects. There was no appreciable association between IDDM and the DPB1 allele in Japanese. The absence of association between IDDM and DP, in spite of the known association between this disease and both DR and DQ, suggests that the HLA locus (loci) telomeric to DP encodes susceptibility to IDDM. 相似文献
64.
Age-hardening mechanisms and related ordering behaviors of the experimental (AuCu)1−xZnx alloys with x0.2 were investigated for dental applications. The addition of Zn to equiatomic AuCu greatly increased the age-hardening rate and delayed overaging. It was suggested that the quenched-in excess vacancies were greatly related to the age-hardening rate in the AuCu–Zn pseudobinary alloys. In these alloys, the hardness became maximum during the very initial stage of ordering, and with the development of ordered phase, the hardness began to decrease. Transmission electron microscopy revealed that the age-hardening of AuCu–Zn pseudobinary alloys is caused by lattice distortion that occurred during the very early stage of atomic ordering. The addition of Zn to AuCu effectively increased the density of antiphase boundaries per unit volume of the AuCu II superstructure. This is suggested to be the main cause for the retardation of the overaging in the alloys containing Zn of 5 at% or more. This pronounced effect of Zn addition to AuCu alloy on its age-hardening characteristics may be advantageous for obtaining stable mechanical properties of dental casting gold alloys. 相似文献
65.
66.
Salt-dependent hemagglutination with bluetongue virus 总被引:1,自引:0,他引:1
Summary Hemagglutination (HA) titers of bluetongue virus (BTV) were increased by higher sodium chloride molarity diluent. HA inhibiting antibodies to BTV hemagglutination proved to be type specific.With 1 Figure 相似文献
67.
BACKGROUND: Chymase is a chymotrypsin-like serine protease primarily stored in mast cells. Infection with helminth parasites is known to increase the level of mast cell chymase in the jejunum and serum in mice. The aim of the present study is to elucidate the role of chymase in helminth infection. METHODS: Chymase inhibitor SUN-C8257 was administered to mice infected with the nematode Nippostrongylus brasiliensis, and the number of eosinophils in the blood, serum IgE levels and fecal egg counts were determined. RESULTS: Administration of SUN-C8257 significantly inhibited blood eosinophilia in BALB/c mice infected with N. brasiliensis. The effect of SUN-C8257 was specific for eosinophils, in that it affected neither the number of total leukocytes nor serum IgE levels. SUN-C8257 did not alter the fecal egg counts in this model, showing that SUN-C8257 has no effect on infectivity and expulsion of the nematode. N. brasiliensis infection induced eosinophilia in mast cell-deficient mice (W/W(v)) as well as their littermates (+/+), and SUN-C8257 inhibited the eosinophilia in +/+ mice but not in W/W(v) mice. These results suggest that the eosinophil number may be regulated by different mechanisms in W/W(v) and +/+ mice, and that the effect of SUN-C8257 on nematode-induced eosinophilia is probably due to chymase inhibition. CONCLUSIONS: Chymase released by activated mast cells may play a role in helminth-induced eosinophilia. 相似文献
68.
Kiyonori Miura Hideaki Masuzaki Tadayuki Ishimaru Norio Niikawa Y. Jinno 《Journal of human genetics》1998,43(4):283-284
We found a HhaI/BstUI polymorphism in the 3′ untranslated region of a novel gene which was localized to 11p15.5. This region is one of prominent
imprinting domains and contains multiple imprinted genes, such as H19, IGF2 , KVLQT1, and p57
KIP2
, which suggests that regional factors might contribute to the imprinting.
This polymorphism will be useful in the allelic analysis of expression and methylation of the novel gene.
Received: July 24, 1998 / Accepted: July 29, 1998 相似文献
69.
Primates are able to track a moving target with their eyes, even when the target is seen against a stationary textured background. In this situation, the tracking eye movement induces motion of the background images on the retina (reafference) that competes with the motion of the target's retinal image, potentially disrupting the tracking of the target. Previous work on humans reported that brief perturbations of the background in the opposite direction to pursuit were much less disruptive than perturbations in the same direction as pursuit. Furthermore, if the background moved together with the pursuit target--so as to effectively eliminate the reafference--then the effects of a subsequent background perturbation showed less dependence on direction. This suggested that the direction selectivity to background perturbations during pursuit against a stationary background was due, at least in part, to the prior motion of the background secondary to the pursuit. We now report similar findings in monkeys, and in addition, have investigated the effect of moving the background while the animal was fixating a stationary target. In this situation, the ocular tracking responses to subsequent brief perturbations of the moving background were weaker when the perturbations were in the same direction as the prior background motion than when in the opposite direction. This suggests that the selective insensitivity to the reafferent visual input associated with pursuit across a stationary background is, at least in part, independent of pursuit per se and attributable to a progressive reduction in the sensitivity to sustained background motion. 相似文献
70.
Preemptive analgesia by zaltoprofen that inhibits bradykinin action and cyclooxygenase in a post-operative pain model 总被引:2,自引:0,他引:2
The post-operative pain state results from a barrage of primary afferent inputs exposed to products of tissue damage such as bradykinin and prostaglandins and the central sensitization by the continuing inputs. This provides the rationale for preemptive analgesia, whereby the blockade of primary afferent inputs prior to injury may result in a reduction of post-operative pain. 2-(10,11-dihydro-10-oxo-dibenzo[b,f]thiepin-2-yl) propionic acid (zaltoprofen) is a unique compound that inhibits cyclooxygenase (COX) and exhibits anti-bradykinin activity. The present study evaluated the preemptive analgesic effect of zaltoprofen in a post-operative pain model produced by plantar incision. When orally, but no intrathecally, administered 30 min prior to incision, zaltoprofen significantly increased the withdrawal threshold 2 h and 1-3 days after incision at 10 mg/kg. While the bradykinin B1 antagonist des-Arg10-HOE-140, the selective COX-1 inhibitor SC-560, and the selective COX-2 inhibitor celecoxib did not affect post-operative pain, the B2 antagonist HOE-140 dose-dependently relieved the post-operative pain at 2-200 microg/kg with a time course similar to that of zaltoprofen. The B2 receptor mRNA was expressed in the hindpaw and the expression did not change before and 24 h after surgery. These results suggest that zaltoprofen produces the preemptive analgesic effect peripherally by blocking the B2 pathway. 相似文献