全文获取类型
收费全文 | 12801篇 |
免费 | 891篇 |
国内免费 | 558篇 |
专业分类
耳鼻咽喉 | 151篇 |
儿科学 | 347篇 |
妇产科学 | 269篇 |
基础医学 | 2016篇 |
口腔科学 | 356篇 |
临床医学 | 763篇 |
内科学 | 2007篇 |
皮肤病学 | 167篇 |
神经病学 | 663篇 |
特种医学 | 464篇 |
外国民族医学 | 6篇 |
外科学 | 911篇 |
综合类 | 1821篇 |
现状与发展 | 4篇 |
预防医学 | 485篇 |
眼科学 | 363篇 |
药学 | 1940篇 |
6篇 | |
中国医学 | 494篇 |
肿瘤学 | 1017篇 |
出版年
2024年 | 38篇 |
2023年 | 148篇 |
2022年 | 316篇 |
2021年 | 384篇 |
2020年 | 358篇 |
2019年 | 358篇 |
2018年 | 343篇 |
2017年 | 332篇 |
2016年 | 358篇 |
2015年 | 414篇 |
2014年 | 742篇 |
2013年 | 863篇 |
2012年 | 724篇 |
2011年 | 853篇 |
2010年 | 638篇 |
2009年 | 686篇 |
2008年 | 744篇 |
2007年 | 664篇 |
2006年 | 604篇 |
2005年 | 583篇 |
2004年 | 490篇 |
2003年 | 452篇 |
2002年 | 386篇 |
2001年 | 339篇 |
2000年 | 267篇 |
1999年 | 272篇 |
1998年 | 260篇 |
1997年 | 202篇 |
1996年 | 204篇 |
1995年 | 162篇 |
1994年 | 120篇 |
1993年 | 144篇 |
1992年 | 92篇 |
1991年 | 78篇 |
1990年 | 67篇 |
1989年 | 57篇 |
1988年 | 44篇 |
1987年 | 48篇 |
1986年 | 43篇 |
1985年 | 59篇 |
1984年 | 78篇 |
1983年 | 44篇 |
1982年 | 45篇 |
1981年 | 29篇 |
1980年 | 29篇 |
1979年 | 29篇 |
1978年 | 19篇 |
1977年 | 18篇 |
1976年 | 10篇 |
1974年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
T. Tsuji P. Shrestha K. Yamada H. Takagi F. Shinozaki K. Sasaki K. Maeda M. Mori 《Virchows Archiv : an international journal of pathology》1992,420(5):377-383
Summary Proliferating cell nuclear antigen (PCNA) is a nuclear protein synthesized in the late G1 and S phase of the cell cycle and immunohistochemical detection of the protein represents a useful marker for the proliferating fraction of cells in tissue specimens. A series of malignant and pre-malignant lesions of the oral cavity and skin were evaluated by the streptavidin biotin immunoperoxidase method for detection of this protein. Monoclonal anti-PCNA antibody (PC 10) labelled proliferating cells in all cases with varying intensity of nuclear staining. In squamous cell carcinoma (n=48), PCNA positivity correlated with the differentiation and atypia of the tumour cells; however, in poorly differentiated tumours, the relationship between PCNA expression and proliferation was lost. Basal cell carcinoma showed an increased growth fraction in tiny epithelial nests (mean 43.8, SD 6.0,n=20) than in neoplastic basal cells (mean 30.1, SD 6.9,n=8). The growth fractions were significantly higher in the pre-malignant lesions (leukoplakia, mean 22.3, SD 7.7,n=14; Bowen's disease, mean 45.2, SD 11.7,n=12; senile keratosis, mean 41.2, SD 7.0,n=12) than in the normal mucosa (mean 9.8, SD 4.9,n=10), suggesting that cellular growth fractions correlate with the degree of dysplasia in pre-malignant lesions. 相似文献
112.
Rawe VY Olmedo SB Nodar FN Ponzio R Sutovsky P 《Human reproduction (Oxford, England)》2003,18(3):576-582
BACKGROUND: The assembly of nuclear pore complexes (NPC) and their cytoplasmic stacks, annulate lamellae (AL), promote normal nucleocytoplasmic trafficking and accompany pronuclear development within the mammalian zygote. Previous studies showed that a percentage of human oocytes fertilized in vitro failed to develop normal pronuclei and cleave within 40-48 h post insemination. We hypothesized that an aberrant recruitment of NPC proteins, nucleoporins and/or NPC preassembled into AL, might accompany human fertilization arrest. METHODS AND RESULTS: We explored NPC and AL assembly in unfertilized human oocytes, and fertilized and arrested zygotes by immunofluorescence with an NPC- and AL-specific antibody, mAb 414, and by transmission electron microscopy. Major NPC or AL assembly was not observed in the unfertilized human oocytes. Once fertilization took place, the formation of AL was observed throughout the cytoplasm and near the developing pronuclei with NPC. On the contrary, NPC assembly was disrupted in the arrested zygotes, whereas AL were clustered into large sheaths. This was accompanied by the lack of NPC incorporation into the nuclear envelopes. CONCLUSIONS: We conclude that the aberrant assembly of NPC and AL coincides with early developmental failure in humans. 相似文献
113.
Elisabet Costa Silvia Canudas Ivan Garcia-Bassets Silvia Pérez Irene Fernández Ernest Giralt Fernando Azorín M. Lluïsa Espinás 《Chromosome research》2006,14(5):515-526
SAP18 is a highly conserved protein that was proposed to be involved in multiple cellular processes from autophagy to gene
regulation and mRNA processing. In this paper we show that, in Drosophila, dSAP18 is a predominantly nuclear protein that associates to both chromosomes and the nuclear matrix. dSAP18 becomes nuclear
early during development, at the onset of cellularization, and remains so all through embryo development. dSAP18 is also nuclear
in salivary glands, ovaries and cultured S2 cells. Here we also show that dSAP18 forms a complex with the Drosophila homolog of pinin (dPnn), a protein factor involved in mRNA splicing. dSAP18-dPnn interaction was confirmed in vivo, through co-immunoprecipitation experiments, as well as in vitro, through GST pull-down assays. These results are discussed in the context of the possible functions played by SAP18. 相似文献
114.
大白鼠外侧隔核的传入性神经纤维联系—HRP、荧光素法研究 总被引:2,自引:0,他引:2
本文应用HRP和荧光素标记法对大白鼠外侧隔核的传入性神经纤维联系进行了研究。实验结果表明,外侧隔核的传入神经纤维来源于端脑海马的CA_(1-4)区、杏仁皮质核、内嗅区皮质、斜角带核、视前内侧核、视前外侧核;丘脑的室周核和带旁核;底丘脑的Forel's H_2区和未定带;下丘脑的前核、外侧核、后核以及乳头体上核;中脑的腹侧被盖区。 相似文献
115.
Martina C. Cornel Anthonie J. van Essen Leo P. ten Kate 《American journal of medical genetics. Part A》1992,42(3):387-392
After the birth of a child with a congenital anomaly, parents have many questions about cause, prognosis, and recurrence risk. An important means of transmitting such information is referral to a genetic clinic. We were interested in knowing what determines whether or not parents are referred for genetic counseling. Data from the local registration of congenital anomalies in the northeastern Netherlands (birth years 1981–1986; 1,217 children/fetuses) and data of the local genetic clinic were compared. The parents of 204 cases (16.8%) had been referred for genetic counseling. Of the couples referred, 76% were referred within one year after birth, usually by a pediatrician (48%). Parents of children with a single anomaly, recognized syndrome, or multiple anomalies not recognized as a syndrome were referred in 5%, 43%, and 26% of cases, respectively. Parents of liveborn children who died were referred in 38% of cases, parents of liveborn/still-alive and stillborn children in 13% and 22%, respectively. Previous affected sibs and absence of previous livebirths increased the likelihood of referral. 相似文献
116.
Seigo Maeo Yoichi Ajioka Hidenobu Watanabe Masaaki Kobayashi Michio Kobayashi 《Pathology international》1995,45(5):359-365
Well-differentiated colorectal adenocarcinomas are subclassified into carcinoma with high-grade atypia (CAH) and carcinoma with low-grade atypia (CAL) based on their cellular atypia. It is proposed that CAH and CAL are different in histologic prognostic factors and that the former should be regarded as carcinoma with high-grade malignancy and the latter as low-grade malignancy. In this study, the differences in cell-proliferative activity between CAH and CAL were examined using a monoclonal antibody to the proliferating cell nuclear antigen (PCNA). The PCNA index and mitotic index of 27 early colorectal carcinomas (9 CAL, 5 CAH, and 13 carcinomas with mixed low- and highgrade atypia) was evaluated in relation to their depth of invasion. In intra-mucosal lesions, both indices were higher in CAH (78%, 0.89%) than in CAL (68%, 0.47%; P <0.01). In lesions invading into the submucosa, the PCNA and mitotic indices were also higher in CAH (7596, 0.65%) than in CAL (35%, 0.19%; P <0.01). A significant correlation was observed between the PCNA index and the mitotic index in the mucosal lesions (P<0.05). These results indicate that CAH has a higher proliferative activity than CAL, and support the current authors' proposal that CAH is a high-grade malignancy and CAL a low-grade malignancy. 相似文献
117.
端粒酶转录酶及其调节相关蛋白与增殖细胞核抗原在卵巢上皮性肿瘤中的表达及临床意义 总被引:2,自引:1,他引:2
目的 探讨端粒酶转录酶 (hTERT)及端粒酶调节相关蛋白 (TRAP)与增殖细胞核抗原(PCNA)在卵巢上皮性肿瘤中的表达和临床意义。方法 收集 10 6例卵巢上皮性肿瘤 (恶性 5 4例 ,交界性 33例 ,良性 19例 )的临床资料 ,行hTERT、TRAP和PCNA 3种抗体的免疫组织化学标记链霉素卵白素生物素 (LSAB)法染色。对 87例恶性和交界性患者进行了随访 ,4 5例获结果 ,随访时间为 2~6 0个月。结果 hTERT蛋白的表达在良性 (4/ 19)和交界性 (90 9% ,30 / 33)以及良性和恶性(94 4 % ,5 1/ 5 4 )间的差异均有显著性 (P均 <0 0 0 1) ,TRAP蛋白的表达在良性 (4/ 15 )和恶性(77 8% ,2 8/ 36 )间的差异有显著性 (P <0 0 0 1) ;hTERT和TRAP蛋白的表达在卵巢癌Ⅰ、Ⅱ期和Ⅲ、Ⅳ期两组病例中的差异均无显著性 (P >0 0 5 ,P >0 3)。PCNA的表达在良性 (6 9± 5 9) %和交界性 (2 6 4± 17 8) %、良性和恶性 (5 1 8± 2 2 1) %以及交界性和恶性间的差异均有显著性 (P <0 0 1,P <0 0 0 1,P <0 0 5 )。 33例交界性患者全部存活 ,5 4例恶性患者中 35例 (6 4 8% )有转移 (包括 5例淋巴结转移 ) ,4例 (7 4 % )死亡。结论 hTERT和TRAP蛋白的表达与卵巢上皮性肿瘤的良恶性有关 ,但与其临床分期无关 ;hTERT和TRAP蛋白的表达相似 相似文献
118.
The enzyme for the synthesis of epinephrine, phenylethanolamine-N-methyltransferase, has been localized, by an indirect immunofluorescent staining method, to a subpopulation of amacrine cells in the rat retina. The immunoreactive cells are located primarily in the inner nuclear layer and send a single process to the inner plexiform layer. Most of the immunoreactivity is found in the center of the inner plexiform layer. A small percentage of immunoreactive cell bodies were found in the inner plexiform layer and occasionally cells were observed in the ganglion cell layer. These epinephrine-containing amacrine cells are morphologically distinct from the dopamine-containing amacrine cells previously described by formaldehyde fluorescence and we speculate from reports in the literature that epinephrine-containing amacrine cells may play a role in modulating the activity of dopamine-containing amacrine cells. 相似文献
119.
120.
AIMS: Studies are disclosing that Epstein-Barr virus (EBV) is involved in the aetiology of various neoplasms including undifferentiated carcinomas of the aerodigestive tract. The aetiology of intrahepatic cholangiocarcinoma (ICC), a malignant neoplasm arising from intrahepatic biliary epithelia, has yet to be fully evaluated. To date, two cases of EBV-related ICC have been reported, and they presented foci of lymphoepitheliomatous undifferentiated carcinoma components. METHODS AND RESULTS: To determine whether EBV is commonly involved in the developments of ICC, we performed in-situ hybridization and immunohistochemistry for EBV in 215 cases of ICC in Japan, using a probe against EBV-coded nuclear RNA (EBER) and a specific antibody against latent membrane protein-1 (LMP-1), respectively. We did not detect EBV-infected carcinoma cells in any of the ICC cases examined. No lymphoepitheliomatous undifferentiated carcinoma components were found either. CONCLUSION: The results suggest that EBV infection is unlikely to be involved in the pathogenesis of ICC. 相似文献