全文获取类型
收费全文 | 5865篇 |
免费 | 329篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 303篇 |
儿科学 | 68篇 |
妇产科学 | 65篇 |
基础医学 | 929篇 |
口腔科学 | 116篇 |
临床医学 | 325篇 |
内科学 | 1378篇 |
皮肤病学 | 70篇 |
神经病学 | 531篇 |
特种医学 | 185篇 |
外科学 | 767篇 |
综合类 | 60篇 |
预防医学 | 208篇 |
眼科学 | 52篇 |
药学 | 585篇 |
中国医学 | 17篇 |
肿瘤学 | 571篇 |
出版年
2023年 | 27篇 |
2022年 | 69篇 |
2021年 | 114篇 |
2020年 | 66篇 |
2019年 | 82篇 |
2018年 | 95篇 |
2017年 | 79篇 |
2016年 | 97篇 |
2015年 | 80篇 |
2014年 | 136篇 |
2013年 | 157篇 |
2012年 | 238篇 |
2011年 | 321篇 |
2010年 | 149篇 |
2009年 | 134篇 |
2008年 | 248篇 |
2007年 | 269篇 |
2006年 | 242篇 |
2005年 | 290篇 |
2004年 | 304篇 |
2003年 | 256篇 |
2002年 | 235篇 |
2001年 | 242篇 |
2000年 | 239篇 |
1999年 | 206篇 |
1998年 | 71篇 |
1997年 | 73篇 |
1996年 | 73篇 |
1995年 | 53篇 |
1994年 | 62篇 |
1993年 | 52篇 |
1992年 | 158篇 |
1991年 | 146篇 |
1990年 | 140篇 |
1989年 | 120篇 |
1988年 | 118篇 |
1987年 | 114篇 |
1986年 | 113篇 |
1985年 | 96篇 |
1984年 | 68篇 |
1983年 | 54篇 |
1982年 | 33篇 |
1981年 | 24篇 |
1980年 | 22篇 |
1979年 | 39篇 |
1978年 | 26篇 |
1977年 | 27篇 |
1974年 | 23篇 |
1973年 | 19篇 |
1971年 | 20篇 |
排序方式: 共有6230条查询结果,搜索用时 15 毫秒
31.
Association of the insertion/deletion polymorphism of the angiotensin I-converting enzyme gene in patients of migraine with aura 总被引:2,自引:0,他引:2
Kowa H Fusayasu E Ijiri T Ishizaki K Yasui K Nakaso K Kusumi M Takeshima T Nakashima K 《Neuroscience letters》2005,374(2):129-131
Recently, several angiotensin I-converting enzyme (ACE) inhibitors and an angiotensin II receptor blocker were demonstrated to have a clinically important prophylactic effect in migraine. ACE is one of the key enzymes in the rennin-angiotensin-aldosterone system, which modulates vascular tension and blood pressure. In humans, serum ACE levels are strongly genetically determined. Individuals who were homozygous for the deletion (D) allele showed increased ACE activity levels. To investigate the role of ACE polymorphism in headache, we analyzed the ACE insertion (I)/deletion (D) genotypes of 54 patients suffering from migraine with aura (MwA), 122 from migraine without aura, 78 from tension-type headache (TH), and 248 non-headache healthy controls. The ACE D allele were significantly more frequent in the MwA than controls (p<0.01). The incidence of the D/D genotype in MwA (25.9%) was significantly higher than that in controls (12.5%; p<0.01; odds ratio=5.26, 95% confidence interval: 1.69-16.34, adjusted for age and gender). No differences in the remaining groups were found. Our results support the conclusion that the D allele and the D/D genotype in the ACE gene is a genetic risk factor for Japanese MwA. There seems to be a possible relationship between ACE activity and the pathogenesis of migraine. 相似文献
32.
33.
Alipov G Nakayama T Ito M Kawai K Naito S Nakashima M Niino D Sekine I 《Histopathology》2005,47(2):202-208
AIMS: The high incidence of clinically diagnosed prostatic cancer is exceeded by the frequency of tumours detected at autopsy. The Ets-1 proto-oncogene is expressed by a variety of malignant and normal tissues. Therefore, in this study, expression of Ets-1 protein was investigated in 'latent' prostatic cancer detected at autopsy, compared with benign prostatic hyperplasia, normal prostatic tissues and clinical prostatic cancer. METHODS AND RESULTS: Using immunohistochemistry, we analysed Ets-1 expression in 95 prostatic specimens including 19 cases of latent prostatic carcinoma (LPC) and 55 cases of clinical prostatic carcinoma (CPC), 11 cases of benign prostatic hyperplasia (BPH) and 10 cases of normal prostate (NP). Differences in the incidence of LPC and CPC suggest different courses for the biological progression of prostatic cancer. There was a significant difference in the degree of Ets-1 expression in CPC and LPC (P < 0.05). Ets-1 was not expressed in BPH and NP, but in malignant cases (57 of 74; 77.0%) commonly demonstrated immunoreactivity in the tumour cells. In our study the expression of Ets-1 between benign and malignant, and well, moderately and poorly differentiated adenocarcinomas of prostatic cancer showed significant differences. The presence of Ets-1 mRNA was confirmed by in-situ hybridization in human prostatic tissues. CONCLUSION: Our results suggest that Ets-1 might play an important role in carcinogenesis and/or the progression of human prostatic carcinomas. 相似文献
34.
Enhanced expression of type I interferon and toll-like receptor-3 in primary biliary cirrhosis 总被引:6,自引:0,他引:6
Takii Y Nakamura M Ito M Yokoyama T Komori A Shimizu-Yoshida Y Nakao R Kusumoto K Nagaoka S Yano K Abiru S Ueki T Matsumoto T Daikoku M Taniguchi K Fujioka H Migita K Yatsuhashi H Nakashima M Harada M Ishibashi H 《Laboratory investigation; a journal of technical methods and pathology》2005,85(7):908-920
35.
Kazuto Nagata Yasuhiro Nakamura Yoshiaki Hosokawa Teruyuki Nakashima Naoki Nagasue Katsuichi Kabashima Shikoh Hidaka 《Pathology international》1981,31(4):695-699
An autopsy case of pulmonary candidiasis occurring in a neonatal girl was reported. The mycological examination of the lung taken at autopsy revealed only Candida albicans and followed by the elucidation under the microscopic sections prepared with special stains; periodic acid-Schiff and methenamine silver, in the lung, stomach, umbilical cord, and amnion. The presence of Candida vaginitis in her mother supported the concept that Candida albicans was the etiological agent of the pulmonary candidiasis. 相似文献
36.
Immunosuppressive activity induced by nitric oxide in culture supernatant of activated rat alveolar macrophages. 下载免费PDF全文
Alveolar macrophages (AM) from normal rats had immunosuppressive activity to mitogen-induced proliferative responses of splenic lymphocytes. We studied the mechanism and the implication of the nitric oxide synthetase pathway in AM-mediated suppression of concanavalin A (Con A)-induced lymphocyte proliferation. The culture supernatant from AM cultures alone did not have immunosuppressive activity to Con A-induced proliferative responses of non-adherent spleen cells (n-ad SC), but the culture supernatant from co-culture of AM and autologous n-ad SC had this activity. Con A-pulsed AM also liberated the immunosuppressive factor. When AM and autologous n-ad SC were cultured separately under the condition that medium could freely communicate, the culture supernatant did not suppress the Con A-induced proliferative response of n-ad SC. This indicated that the immunosuppressive factor was liberated when AM was activated by cell-to-cell contact with n-ad SC. Further, we examined the immunosuppressive activity of the culture supernatant of co-culture of AM and autologous n-ad SC to Con A-induced responses of allogeneic n-ad SC and xenogeneic murine n-ad SC, and allogeneic mixed leucocyte reaction, and found that this culture supernatant could suppress all these proliferative responses. Nitrate (NO2-) synthesis was markedly augmented in the culture supernatants of Con A-pulsed AM and co-culture of AM and n-ad SC. NG-monomethyl-L-arginine (MMA), a specific competitive inhibitor of the nitric oxide synthetase pathway (NOSP), extinguished both NO2- synthesis by AM and AM-mediated immunosuppressive activity. These data suggest that NOSP was important in AM-mediated suppression of Con A-induced lymphocyte proliferation. 相似文献
37.
Inflammation Research - 相似文献
38.
Evaluation of a Membrane Filter Assay System, Ortho HCV Ab Quik Pack, for Detection of Anti-Hepatitis C Virus Antibody 下载免费PDF全文
Takanari Kodama Satoshi Ichiyama Kumiko Sato Toshi Nada Nobuo Nakashima 《Journal of clinical microbiology》1998,36(5):1439-1440
A simple membrane immunoassay assay system, Quik Pack, for the detection of hepatitis C virus antibody was compared with two enzyme-linked immunosorbent assays (ELISAs) in a study of 600 serum samples. Quik Pack exhibited excellent sensitivity and specificity: 96.0 and 99.7%, respectively, versus the ELISA-2 and 99.7 and 99.4%, respectively, versus the ELISA-3. 相似文献
39.
Yanagisawa M Nakashima K Ochiai W Takizawa T Setoguchi T Uemura A Takizawa M Nobuhisa I Taga T 《Neuroscience research》2005,53(2):176-182
Mammalian cells that have been committed to a certain cell lineage cannot be directed to other lineages. However, some astrocytes in the mammalian brains have been reported to represent plasticity to redirect to other cell lineages. We found that mouse hippocampal astrocytes cultured in aggregate forms of "astrosphere", redirected to MAP2-positive immature neurons. In astrospheres, basic HLH factors positively regulating neuronal differentiation were up-regulated and Id3 inhibiting basic HLH factors was down-regulated. Ectopic Id3 induction repressed redirection of astrocytes to a neuronal lineage, suggesting that astrosphere formation induced plasticity of astrocytes by changing the gene expression patterns. 相似文献
40.
Campsmith ML Nakashima AK Jones JL 《Journal of acquired immune deficiency syndromes (1999)》2000,25(2):192-198
OBJECTIVE: To describe the prevalence of crack cocaine use in an HIV-infected population and to examine the association between crack use after HIV diagnosis and high-risk sexual behaviors for heterosexual men, heterosexual women, and men who have sex with men (MSM). METHODS: Analysis of cross-sectional interviews conducted from January 1995 through December 1998 with HIV infected adults in 12 states. RESULTS: Of 10,415 persons with HIV or AIDS, 66.6% never used crack, 10.7% used crack before HIV diagnosis but not after, and 22.7% used crack after diagnosis. High-risk sexual behaviors were more prevalent among those who had ever used crack and were most prevalent among those who used crack after diagnosis. In multivariable analyses, crack use after diagnosis was associated with having multiple sex partners and trading sex for drugs/money in all three groups: heterosexual men, heterosexual women, and MSM. For heterosexual women and MSM, crack use after diagnosis was associated with unprotected sex with a main partner, and among heterosexual men and MSM, with unprotected sex with casual partners. CONCLUSIONS: Crack use after HIV diagnosis was associated with high-risk sexual behaviors. Treatment programs to assist people in quitting crack are needed to help reduce the risk of HIV transmission from this population. 相似文献