全文获取类型
收费全文 | 11555篇 |
免费 | 651篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 88篇 |
儿科学 | 176篇 |
妇产科学 | 176篇 |
基础医学 | 1467篇 |
口腔科学 | 456篇 |
临床医学 | 786篇 |
内科学 | 2755篇 |
皮肤病学 | 355篇 |
神经病学 | 838篇 |
特种医学 | 444篇 |
外科学 | 1802篇 |
综合类 | 63篇 |
预防医学 | 493篇 |
眼科学 | 182篇 |
药学 | 1057篇 |
中国医学 | 20篇 |
肿瘤学 | 1096篇 |
出版年
2023年 | 74篇 |
2022年 | 140篇 |
2021年 | 238篇 |
2020年 | 132篇 |
2019年 | 192篇 |
2018年 | 237篇 |
2017年 | 181篇 |
2016年 | 206篇 |
2015年 | 191篇 |
2014年 | 267篇 |
2013年 | 366篇 |
2012年 | 568篇 |
2011年 | 577篇 |
2010年 | 326篇 |
2009年 | 280篇 |
2008年 | 515篇 |
2007年 | 565篇 |
2006年 | 571篇 |
2005年 | 599篇 |
2004年 | 544篇 |
2003年 | 525篇 |
2002年 | 534篇 |
2001年 | 370篇 |
2000年 | 408篇 |
1999年 | 354篇 |
1998年 | 113篇 |
1997年 | 90篇 |
1996年 | 92篇 |
1995年 | 69篇 |
1994年 | 67篇 |
1993年 | 58篇 |
1992年 | 235篇 |
1991年 | 214篇 |
1990年 | 208篇 |
1989年 | 235篇 |
1988年 | 206篇 |
1987年 | 201篇 |
1986年 | 178篇 |
1985年 | 166篇 |
1984年 | 122篇 |
1983年 | 105篇 |
1981年 | 53篇 |
1979年 | 92篇 |
1978年 | 61篇 |
1977年 | 56篇 |
1973年 | 59篇 |
1972年 | 57篇 |
1971年 | 51篇 |
1969年 | 67篇 |
1968年 | 76篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Satoru Miyawaki Ryuichi Yamazaki Takehiko Harada Shigehiko Takanashi Tadashi Nagashima Hiroshi Nakaguchi Ryo Okazaki Kazuhito Yamazaki Yasuo Ishida Akira Matsuno 《Journal of clinical neuroscience》2007,14(5):481-484
Skull metastasis of thyroid carcinoma is rare. The majority of skull metastases of thyroid carcinoma are of the follicular subtype, rather than thyroid papillary carcinoma. In this report, a 55-year-old woman with skull metastasis from thyroid papillary carcinoma is presented. The metastatic lesion of the skull was hypervascular and osteolytic, and the bleeding was profuse during resection. There have been only four reports of skull metastasis from thyroid papillary carcinoma. The mean period from the initial diagnosis of thyroid carcinoma until the detection of skull metastasis is 23.3 years, whereas in this patient, it was about 2 years. Therefore, in the clinical course of thyroid papillary carcinoma, skull metastasis should be considered, and the patient should be meticulously followed up. 相似文献
32.
Four novel mutations in the thiazide-sensitive Na-Cl co-transporter gene in Japanese patients with Gitelman's syndrome. 总被引:3,自引:1,他引:2
Nobuki Maki Atsushi Komatsuda Hideki Wakui Hiroshi Ohtani Akihiko Kigawa Namiko Aiba Keiko Hamai Mutsuhito Motegi Akihiko Yamaguchi Hirokazu Imai Ken-ichi Sawada 《Nephrology, dialysis, transplantation》2004,19(7):1761-1766
BACKGROUND: Gitelman's syndrome (GS) is an autosomal recessive disorder resulting from inactivating mutations in the thiazide-sensitive Na-Cl co-transporter (NCCT) gene. To date, almost 90 mutations have been identified. It is possible that there is a population-specific distribution of mutations. In this study, we analysed mutations in the NCCT gene of seven Japanese patients with GS. METHODS: Peripheral blood mononuclear cells were isolated from patients with GS, their family members and healthy control subjects. A mutation analysis of the NCCT gene was performed completely by direct automated sequencing of polymerase chain reaction-amplified DNA products. In patients with a deletion or splice site mutation, we undertook cDNA sequence analysis. RESULTS: We identified nine mutations. Five of them [c.185C>T (Thr60Met), c.1712C>T (Ala569Val), c.1930C>T (Arg642Cys), c.2552T>A (Leu849His) and c.1932delC] have been reported in Japanese patients, but not in GS patients from other ethnic groups. The remaining four mutations [c.7A>T (Met1Leu), c.1181_1186+20del26, c.1811_1812delAT and IVS16+1G>A] were novel. In cDNA derived from a patient with c.1181_1186+20del26, a deletion of exon 9 and a frameshift at the start of exon 10 were observed. In cDNA derived from patients with IVS16+1G>A, an additional 96 bp insertion between exons 16 and 17 was observed. Six out of seven patients were compound heterozygotes, and the remaining one carried a single heterozygous mutation. CONCLUSIONS: We found four novel mutations in the NCCT gene in seven Japanese patients with GS. Moreover, our study suggests that the distribution of mutations in the NCCT gene in Japanese GS patients potentially differs from that in other populations. 相似文献
33.
Kazue Shimmoto Shinichiro Ushigome Takashi Nikaido YaSUShi Kikuchi Naoaki Kobayashi Yohji Yamazaki 《Pediatric hematology and oncology》1991,8(2):147-157
A case is reported of Wilms' tumor associated with multiple pulmonary metastases histologically showing maturation of the tumor cells at 9 years after the resection of the primary tumor and intensive therapy. A huge tumor of a 22-month-old patient's right kidney was resected. The tumor was diagnosed as Wilms' tumor of mesenchymal type (stage 1), which consisted of predominantly immature mesenchymal tissue including rhabdomyoblasts, smooth muscle and fibrous tissue, and few blastemal and epithelial components. Intensive preoperative and postoperative chemotherapy with actinomycin D and vincristine and postoperative irradiation therapy totaling 16 Gy were carried out. The patient was regularly followed up uneventfully until 9 years after the surgery. On routine chest x ray at the age of 10 years 11 months, multiple pulmonary nodules were found. The excised nodules from the bilateral lungs disclosed similar histology, exclusively composed of dense collagen bundles and fibrocytes intermingled with mature striated muscle bundles. No immature tumor components were detected. The possible effect of intensive therapy in this maturation was stressed, although spontaneous benign differentiation of tumor cells cannot be excluded. 相似文献
34.
Blood pressure and heart rate changes were recorded on supine or prone head-up tilt and on carotid artery occlusion in normal and streptozotocin diabetic rats (65 mg/kg). In general supine tilt induced a larger blood pressure fall, slower blood pressure recovery from the fall and larger heart rate fall than prone tilt, both in normal and diabetic rats. Heart rate recovery from the fall was slightly larger in prone than in supine tilt in normal rats. The blood pressure fall and heart rate fall accompanying the tilt were statistically larger in diabetic than in normal rats. Furthermore, blood pressure recovery from the fall was statistically more rapid and larger in normal than in diabetic rats. The exaggerated blood pressure fall with the tilt of diabetic rats might correspond to postural hypotension. Blood pressure rise and heart rate rise with carotid artery occlusion were smaller in diabetic than in normal rats. Blood pressure changes with cervical sympathetic or vagus stimulation were almost the same in normal and diabetic rats. However, in diabetic rats such cervical autonomic nerve stimulation produced larger heart rate changes than in normal rats. 相似文献
35.
K Takayasu Y Muramatsu N Moriyama S Yamazaki T Takayama S Hirohashi Y Shimamura A Takahashi 《Journal of computer assisted tomography》1992,16(2):212-215
To differentiate focal nodular hyperplasia (FNH) from other hepatic tumors, especially hepatocellular carcinoma, we evaluated the hemodynamics of histologically proved FNH in three patients, two by arterial angio-CT and one by microangiography of the resected specimen. These studies demonstrated the centrifugal blood supply of FNH (early filling of central tumor vessels radiating to periphery, and lobulated tumor stains with central low density area in the late phase), which could not be demonstrated by dynamic CT or hepatic angiography. Arterial angio-CT is useful as a further study, when differential diagnosis of FNH is uncertain by other imaging techniques. 相似文献
36.
T Yamazaki 《Kansenshōgaku zasshi. The Journal of the Japanese Association for Infectious Diseases》1992,66(5):632-636
A strain of Chlamydia pneumoniae (C. pneumoniae) which had been isolated from a Japanese child (AC-43) was examined morphologically and serologically using micro-immunofluorescent (micro-IF) test. Inclusions of AC-43 were stained by an indirect immunofluorescent method using C. pneumoniae specific monoclonal antibody. They were dense round inclusions which had been reported as a characteristic figure for C. pneumoniae. An elementary body (EB) of AC-43 was pear-shaped by electron micrograph, which was the same as previous reports for C. pneumoniae. We produced monoclonal antibodies using purified EB of AC-43 as antigen. Culture fluids of these clones reacted with C. pneumoniae antigens, but did not react with C. trachomatis or C. psittaci antigens by micro-IF tests. There was no difference in morphological and serological findings among standard strains and Japanese isolate of C. pneumoniae. 相似文献
37.
Purification and characterization of human immunodeficiency virus type 1 nef gene product expressed by a recombinant baculovirus 总被引:5,自引:0,他引:5
Y Matsuura M Maekawa S Hattori N Ikegami A Hayashi S Yamazaki C Morita Y Takebe 《Virology》1991,184(2):580-586
We have constructed the recombinant baculovirus which expresses the human immunodeficiency virus type 1 negative factor (nef) gene. Spodoptera frugiperda cells infected with the recombinant virus produced a 27-kDa protein which reacted with rabbit antisera raised against a carboxy-terminal synthetic peptide of the Nef protein by immunoblot analysis. Labeling experiment showed that the recombinant Nef protein was myristoylated. The recombinant Nef protein was purified to near homogeneity by DEAE-Sephacel, phenyl-Sepharose 4B, blue-Sepharose, and Sephadex G-150 column chromatography. No detectable GTP binding activity was observed in the purified recombinant Nef product. 相似文献
38.
H Yamazaki Y Oda Y Funae S Imaoka Y Inui F P Guengerich T Shimada 《Carcinogenesis》1992,13(6):979-985
The possible roles of cytochrome P450 (P450) enzymes in the metabolic activation of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) by rat liver microsomes have been examined in a system containing the bacterial tester strain Salmonella typhimurium NM2009, a newly developed strain showing high O-acetyltransfer activities. The DNA-damaging activity could be determined by measuring expression of the umu gene in a plasmid containing the fused umuC-lacZ gene construct in the bacteria. The following lines of evidence support the view that both NDMA and NDEA are principally oxidized to reactive products by P450 2E1 in rat liver microsomes. First, NDMA and NDEA were activated by rat liver microsomes in a protein- and substrate-dependent manner and the former chemical was more active than the latter; both activities were induced in rats treated with P450 2E1 inducers such as ethanol, acetone and isoniazid and by starvation. Second, activation of NDMA and NDEA were both inhibited significantly by antibodies raised against rat P450 2E1 and by P450 2E1 inhibitors such as diethyldithiocarbamate and 4-methylpyrazole in rat liver microsomes. Finally, in reconstituted monooxygenase systems containing purified rat P450 enzymes, P450 2E1 gave the highest rates of the activation of both NDMA and NDEA; the addition of rabbit cytochrome b5 to the system caused about a 1.5-fold increase in both reactions. In separate experiments we also found that N-nitrosomethylacethoxymethylamine, a compound that reacts with DNA after ester cleavage, is more genotoxic in S.typhimurium NM2009 than in S.typhimurium NM2000, a strain that is defective in O-acetyltransferase activity. Part of the pathway involved in the activation of nitrosamines is suggested to be acetylation of alkyldiazohydroxides formed by P450 or acetylesterase, because the genotoxic activity of N-nitrosomethylacethoxymethylamine in S.typhimurium NM2009 could be inhibited by the O-acetyltransferase inhibitor pentachlorophenol. These results indicate that NDMA and NDEA are oxidized to gentoxoic products by rat liver microsomes and that a P450 2E1 enzyme plays a major role in the activation of these two potent carcinogens. The activation pathway of N-nitrosodialkylamines through acetylation by O-acetyltransferase has been proposed. This simple bacterial system for measuring genotoxicity should facilitate studies on the activation of N-nitroso alkylamines. 相似文献
39.
Changes in water intake after hepatic vagotomy were examined in the body weights of 3 different rats (about 100, 200 and 280 g). The vagotomy reduced water intake only in the 100-g rats. 相似文献
40.