全文获取类型
收费全文 | 6127篇 |
免费 | 295篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 72篇 |
妇产科学 | 69篇 |
基础医学 | 857篇 |
口腔科学 | 153篇 |
临床医学 | 419篇 |
内科学 | 1422篇 |
皮肤病学 | 129篇 |
神经病学 | 586篇 |
特种医学 | 156篇 |
外科学 | 1028篇 |
综合类 | 32篇 |
一般理论 | 5篇 |
预防医学 | 280篇 |
眼科学 | 107篇 |
药学 | 438篇 |
中国医学 | 21篇 |
肿瘤学 | 648篇 |
出版年
2023年 | 49篇 |
2022年 | 82篇 |
2021年 | 161篇 |
2020年 | 73篇 |
2019年 | 96篇 |
2018年 | 115篇 |
2017年 | 95篇 |
2016年 | 120篇 |
2015年 | 123篇 |
2014年 | 154篇 |
2013年 | 207篇 |
2012年 | 303篇 |
2011年 | 315篇 |
2010年 | 187篇 |
2009年 | 154篇 |
2008年 | 277篇 |
2007年 | 295篇 |
2006年 | 307篇 |
2005年 | 287篇 |
2004年 | 280篇 |
2003年 | 296篇 |
2002年 | 294篇 |
2001年 | 239篇 |
2000年 | 220篇 |
1999年 | 208篇 |
1998年 | 79篇 |
1997年 | 48篇 |
1996年 | 56篇 |
1995年 | 37篇 |
1994年 | 30篇 |
1993年 | 38篇 |
1992年 | 114篇 |
1991年 | 125篇 |
1990年 | 97篇 |
1989年 | 116篇 |
1988年 | 87篇 |
1987年 | 89篇 |
1986年 | 56篇 |
1985年 | 57篇 |
1984年 | 51篇 |
1983年 | 52篇 |
1979年 | 32篇 |
1978年 | 25篇 |
1977年 | 23篇 |
1976年 | 24篇 |
1975年 | 20篇 |
1973年 | 29篇 |
1972年 | 29篇 |
1971年 | 28篇 |
1969年 | 21篇 |
排序方式: 共有6455条查询结果,搜索用时 31 毫秒
81.
82.
Uchibori E Kitano E Tsuji T Kitamura H 《Rinsho byori. The Japanese journal of clinical pathology》2002,50(8):815-819
It is generally accepted that levels of serum whole complement activity (CH50) reflect the activities of complement (C) components of the classical C pathway (CP), since CH50 is assayed by use of sensitized sheep erythrocytes (EA). However, the alternative C pathway (AP) is considered to be also activated simultaneously in the process of activation of serum CP by EA. Thus, serum CH50 levels may possibly reflect not only CP but also AP activation in CH50 assay. We studied on the influence of AP activation during CH50 assay on CH50 levels, by comparison of CH50 levels in serum samples before and after treatment of factor D depletion. Polystyrene beads carrying polyanion, poly (2-acrylamide 2-methylpropane sulfonate) (PAMPS-beads), on the surface were prepared and used for preparation for factor D-depleted serum. After treatment of pooled normal human serum (NHS) with PAMPS-beads (2.5 mg/ml of serum), serum ACH50 level decreased to be undetectable, indicating that AP activation is prohibited in PAMPS-beads-treated serum. When isolated factor D was added to this PAMPS-beads-treated serum, ACH50 level recovered to that of before treatment. Immunoblot analysis revealed that factor D band observed in NHS disappeared completely after PAMPS-beads treatment. From these results, it is clear that factor-D deficient serum is prepared by PAMPS-beads treatment. Besides, since serum CH50 level was not decreased by PAMPS-beads treatment, it may be concluded that CH50 level is not affected by AP activation during CH50 assay. 相似文献
83.
Atsuko Iwasa Yoshinao Oda Shuichi Kurihara Yoshihiro Ohishi Masafumi Yasunaga Izumi Nishimura Emi Takagi Hiroaki Kobayashi Norio Wake Masazumi Tsuneyoshi 《Pathology international》2008,58(12):757-764
Ovarian mature cystic teratomas (MCT) uncommonly undergo malignant transformation to squamous cell carcinoma (SCC). While alterations in the p53 tumor suppressor gene and protein have been shown, few studies have analyzed other molecular changes leading to this malignant conversion. The purpose of the present study was to investigate 21 samples of SCC arising in MCT for altered expression in known p53‐ and p16/Rb‐dependent cell cycle regulatory proteins, and the association between their expression and cellular proliferation and histological features. Overexpression of the p53 protein was observed in 14 SCC (67%), while four (19%) had point mutations in the p53 gene. Reduced expression of the p16 protein was observed in 18 SCC (86%), while p16 gene alterations (hypermethylation (29%) and point mutation (33%)) were found in 11 (52%). Furthermore, a statistically significant correlation was observed between p53 and Rb overexpression (P = 0.0010), and the overexpression of both p53 and Rb was respectively significantly correlated with increased cellular proliferation. The results indicate that alterations in both the p53 and p16‐Rb pathways are associated with SCC arising in MCT. 相似文献
84.
Tatsuo Yamazaki Shigeki Tomita Kazuhito Ichikawa Yuko Ono Fujiyuki Inaba Ichio Fukasawa Yasuo Imai Johji Imura Hirokazu Fukui Takahiro Fujimori Noriyuki Inaba 《Pathobiology》2006,73(4):176-182
OBJECTIVES: We investigated the relationship between P16-immunostaining patterns and clinicopathological factors in early uterine cervix cancers and assessed whether P16-immunostaining patterns predict the prognosis of the patients with early uterine cervix cancers. METHODS: Twenty-nine early squamous cell carcinoma (SCC) specimens of the uterus were examined using immunohistochemistry for P16 expression. The P16-immunostaining pattern was classified into two groups: the homogeneous type and the heterogeneous type. P16-immunostaining patterns were evaluated in different parts of the carcinoma in situ (CIS): the center of the tumor and the front interface of the infiltrating tumor. RESULTS: All specimens were of the homogeneous type in CIS. The P16-immunostaining pattern was significantly of the heterogeneous type in the front interface of the infiltrating tumor with lymphatic invasion, vascular invasion, lymph node metastasis, and recurrence. Regarding the P16-immunostaining patterns in the front interface of the infiltrating tumor, the patients with the heterogeneous type showed a significantly worse prognosis than the patients with the homogeneous type. CONCLUSIONS: The prognosis of patients with early uterine cervical SCC may be predicted by evaluating the P16-immunostaining pattern in the front interface of the infiltrating tumor. 相似文献
85.
Terada Y Imoto I Nagai H Suwa K Momoi M Tajiri T Onda M Inazawa J Emi M 《American journal of medical genetics》2001,103(2):176-180
We performed molecular analysis of a germline interstitial deletion of chromosome 4 [del(4)(q21.22q23)], which had been observed in a male infant manifesting early-onset hepatoblastoma (HBL). The chromosomal anomaly in this child was associated with a unique congenital syndrome including HBL, atrial septal defect, ventricular septal defect, patent ductus arteriosus, mental retardation, and seizures. However, the patient did not exhibit a megalencephaly typical of 4q21-22 deletions. His HBL was associated with an increasing serum alpha-fetoprotein level and rapid growth. To define the chromosomal deletion at the molecular level in this child, we analyzed his lymphoblasts with fluorescence in situ hybridization, using as probes a panel of BAC/PAC genomic clones containing STS markers covering the 4q12-27 region. The analysis revealed that the affected chromosome had an 8-cM deletion within 4q21-q22, flanked by markers D4S2964 and D4S2966. This microdeletion overlaps with the commonly deleted region at 4q21-q22 that was recently defined in adult hepatocellular carcinomas. 相似文献
86.
87.
Tatsuo Michiue Akimasa Fukui Akira Yukita Kenji Sakurai Hiroki Danno Akira Kikuchi Makoto Asashima 《Developmental dynamics》2004,230(1):79-90
Wnt signaling pathways are involved during various stages in the development of many species. In Xenopus, the accumulation of beta-catenin on the dorsal side of embryo is required for induction of the organizer, while the head structure formation requires inhibition of Wnt signaling. Here, we report a role for xIdax, a negative regulator of Wnt signaling. XIdax is expressed in neural tissues at the neurula stage, and in the restricted region of the tadpole brain. Ectopic expression of xIdax inhibits the target gene expression, suggesting that xIdax can inhibit canonical Wnt signaling. To examine the function of xIdax, a morpholino oligo for xIdax (xIdaxMO) was designed. An injection into an animal pole cell caused a loss of forebrain. The anterior neural marker expression is decreased in xIdaxMO-injected embryo, suggesting that xIdax is required for anterior neural development. Moreover, a negative regulator that acts downstream of xIdax rescued this defect. We propose that Idax functions are dependent on the canonical Wnt pathway and are crucial for the anterior neural development. 相似文献
88.
Satoda T Hiyama S Karukaya E Hayashida K Uchida T 《Kaibogaku zasshi. Journal of anatomy》2003,78(3):95-101
It is difficult to teach students about the embryological transformation of the branchial arteries. In mammals, six pairs of branchial arteries develop, but all are not present at the same embryological stage. The first, second, fifth and a part of right sixth branchial artery disappear early in embryological development. The remaining third, fourth and sixth branchial arteries mainly constitute the arterial system of the breast. The aorta and pulmonary trunk are derived from the truncus arteriosus. Because of the complexity of this developmental process, we have devised a user-friendly model in order to assist with educational presentations. In this model, the shrinkage of a vessel has been represented by inserting a wire inside of the hose representing the artery. Degenerated or disappearing parts of the vessel are removable by using hooks and Velcro tape. Branchial arteries, truncus arteriosus, aortic sac and dorsal arteries are represented by different colors. The descent of the heart is represented by the relational change between larynx and heart. Additionally we represented the vagus nerve and recurrent laryngeal nerve by using strings. The right vagus nerve can move dorsally and the left ventrally by rotating the digestive tract. The right recurrent laryngeal nerve can move superiorly to hook around the right subclavian artery, and left recurrent laryngeal nerve can hook around the ductus arteriosus formed by the left sixth branchial artery. 相似文献
89.
Analysis of the detailed genomic structure of human N-cadherin revealed that the 16-exon gene is more than 72 kb in length
and that it consists of a mosaic of exons. Five repeated cadherin domains, a transmembrane domain, and a cytoplasmic domain
are encoded by exons 4 to 13, 13 and 14, and 14 to 16, respectively. A search for molecular variants in the entire coding
region in 96 Japanese individuals resulted in the identification of eight sequence polymorphisms including three CCT- or GCC-type
trinucleotide repeat polymorphisms adjacent to the initiation codon and five other novel single-nucleoticle polymorphisms
(SNPs) in the coding region. Three of the five SNPs accompanied an amino acid substitution: Ala118Thr, Ala826Thr, and Asn845Ser.
Knowlege of the fine gene structure and eight novel polymorphisms will be useful for the genetic study of the role of N-cadherin
in diseases involving cell adhesion in the brain and in cardiomyocytes.
Received: January 23, 2002 / Accepted: March 12, 2002 相似文献
90.
We used a recombinant retrovirus as one of the potential vectors for human gene therapy to transfer a drug sensitivity gene into human lung cancer cells. The gene encoding the thymidine kinase (TK) of herpes simplex virus type 1 (HSV1) was used as the drug sensitivity gene. The antiherpes drugs acyclovir (ACV) and ganciclovir (GCV) were chosen to test the HSV1-TK activity transferred into the human lung cancer cell lines. The rationale for this approach was that ACV and GCV are nucleoside analogs specifically converted by HSV1-TK to a toxic form capable of inhibiting DNA synthesis or disrupting cellular DNA replication. The results obtained from our experiments demonstrate that the retroviral vector-mediated HSV1-TK gene transfer leads to ACV- and GCV-dependent cytotoxicity in human lung cancer cell lines, including both small-cell carcinoma and nonsmall-cell carcinoma. Although the gene transfer of HSV1-TK gene into tumor cells would be one model for gene therapy to control lung cancer, further investigations are necessary for the proper choice of the therapeutic gene and vector targeting such as tumor cell specific delivery of the gene or tumor cell specific expression of the transduced gene.Abbreviations
ACV
Acyclovir
-
GCV
Ganciclovir
-
HSV1
Herpes simplex virus type 1
-
LTR
Long terminal repeat
-
TK
Thymidine kinase 相似文献