全文获取类型
收费全文 | 29243篇 |
免费 | 1551篇 |
国内免费 | 146篇 |
专业分类
耳鼻咽喉 | 373篇 |
儿科学 | 659篇 |
妇产科学 | 579篇 |
基础医学 | 3813篇 |
口腔科学 | 719篇 |
临床医学 | 2320篇 |
内科学 | 7722篇 |
皮肤病学 | 339篇 |
神经病学 | 2467篇 |
特种医学 | 778篇 |
外科学 | 4483篇 |
综合类 | 157篇 |
一般理论 | 11篇 |
预防医学 | 1286篇 |
眼科学 | 389篇 |
药学 | 1951篇 |
中国医学 | 51篇 |
肿瘤学 | 2843篇 |
出版年
2023年 | 160篇 |
2022年 | 259篇 |
2021年 | 589篇 |
2020年 | 334篇 |
2019年 | 415篇 |
2018年 | 554篇 |
2017年 | 408篇 |
2016年 | 509篇 |
2015年 | 528篇 |
2014年 | 744篇 |
2013年 | 962篇 |
2012年 | 1417篇 |
2011年 | 1533篇 |
2010年 | 834篇 |
2009年 | 763篇 |
2008年 | 1414篇 |
2007年 | 1484篇 |
2006年 | 1395篇 |
2005年 | 1378篇 |
2004年 | 1354篇 |
2003年 | 1263篇 |
2002年 | 1299篇 |
2001年 | 926篇 |
2000年 | 948篇 |
1999年 | 837篇 |
1998年 | 360篇 |
1997年 | 272篇 |
1996年 | 254篇 |
1995年 | 219篇 |
1994年 | 195篇 |
1993年 | 164篇 |
1992年 | 618篇 |
1991年 | 645篇 |
1990年 | 551篇 |
1989年 | 554篇 |
1988年 | 537篇 |
1987年 | 516篇 |
1986年 | 436篇 |
1985年 | 440篇 |
1984年 | 328篇 |
1983年 | 252篇 |
1979年 | 240篇 |
1978年 | 141篇 |
1977年 | 146篇 |
1974年 | 132篇 |
1973年 | 122篇 |
1972年 | 141篇 |
1971年 | 129篇 |
1969年 | 140篇 |
1967年 | 130篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
Masahiko Saito 《SANGYO EISEIGAKU ZASSHI》2003,45(4):139-143
Although occult urinary blood in health examinations is common in healthy employees, in the majority with occult urinary blood usually no further examination or treatment is necessary, but occult urinary blood could be an early symptom in urinary tract malignancy. In this study the data on health examinations of male employees with occult urinary blood were analyzed from 1999 to 2002 and strategies for them were discussed. The subjects were male employees working in a steel company, 1,135 ('99), 1,077 ('00), 994 ('01) and 945 ('02). The positive ratios of occult urinary blood were 8.6% in '99, 7.6% in '00, 7.8% in '01, 8.3% in '02, respectively. Multiple logistic regression analysis showed that age and urinary protein were significant factors associated positively with occult urinary blood. In general, a man who had urinary tract malignancy would have macroscopic hematuria in the course of the disease. Therefore, in people with recurrent occult urinary blood the risk of urinary malignancy is considered to be rare. The follow-up protocol was set up for employees with occult urinary blood. For four years 6 employees were referred to specialists (5 to a urologist and 1 to a nephrologist). No significant disease, including urinary tract malignancy, was detected. 相似文献
82.
Y Shiokawa M Nobunaga T Saito T Sakita T Miwa K Nakamura A Gunji K Aoki 《Ryūmachi》1991,31(5):554-571
83.
Chihaya Maesawa Gen Tamura Yasushi Suzuki Kaoru Ishida Kazuyoshi Saito Ryoichi Satodate 《Cancer science》1992,83(12):1253-1256
For the rapid and sensitive detection of p53 gene mutations in esophageal endoscopic biopsy specimens, we combined cell sorting with the polymerase chain reaction and single-strand conformation polymorphism (PCR-SSCP) analysis. Mutations in exons 5–8 of the p53 gene were investigated by FCR-SSCF analysis using 103 sorted nuclei obtained from each endoscopic biopsy specimen of 16 patients with esophageal cancer. DNAs extracted from their respective surgical specimens were investigated by a conventional method of PCR-SSCP analysis. Mutations in the biopsy specimens were detected in 6 of the 12 aneuploid tumors but in none of the 4 diploid tumors. After tumor cell enrichment by cell sorting, one mutation in exon 8 became apparent, which could not be detected from the surgical specimen by a conventional method of PCR-SSCP analysis. This method should improve the sensitivity of detecting p53 gene mutations, and provides additional information concerning the DNA ploidy pattern in the tumors. 相似文献
84.
85.
Seishiro Hirano Takako Asami Naomi Kodama Kazuo T. Suzuki 《Archives of toxicology》1994,68(7):444-449
In a preceding study, we reported that the numbers of macrophages and polymorphonuclear leukocytes (PMN) were increased in
bronchoalveolar lavage fluid (BALF) following the intratracheal instillation of nickel sulfate (NiSO4) in rats. In the present study, BALF chemotactic activities for both macrophages and PMN were measured to investigate if
the increases of these inflammatory cells in BALF depend on increases in chemotactic activities in epithelial lining fluid
(ELF) of the lung. Both the number of PMN and the PMN chemotactic activity peaked at 2 days post-instillation and they were
significantly correlated. However, the PMN chemotactic activity was inversely correlated with concentration of leukotriene
B4 (LTB4), a well-known chemotaxin. Although PMN were not observed in control BALF, LTB4 concentration in the control ELF (ca. 5×10–7 M) was estimated to have a potential to attract PMN chemotactically through a membrane in in vitro migration assay. These
results suggest that the presence of LTB4 in ELF itself does not trigger transpulmonary PMN infiltration. The rat BALF were fractionated by high performance liquid
chromatography (HPLC), and PMN chemotactic activity of each fraction was measured. The elution profiles of PMN chemotactic
activity showed that there were at least two different chemotaxins in BALF obtained from the NiSO4-exposed rats. Macrophage chemotactic activity in BALF also peaked at 2 days post-instillation. However, the number of macrophages
was not significantly correlated with the chemotactic activity for macrophage in BALF. The HPLC study showed that the macrophage
chemotactic substance in the BALF obtained from NiSO4-exposed rats was different from complement fragment (C5a) and its MW was estimated to be 10 – 12 kD.
Received: 1 December 1993/Accepted: 16 March 1994 相似文献
86.
87.
给大鼠经气管分别注入4、16、64mg石英粉尘生理盐水混悬液。在染尘后第7,15和30天解剖动物,测定血浆中Cu、Zn,Mn、Mo、Si、Rb和Sr等7种微量元素的含量。实验结果表明,随着染尘剂量的增加,血浆中铜的含量明显增高,呈正相关,相关系数为0.999。而血浆锌的含量随着染尘剂量的增加而明显的降低,呈负相关,相关系数为-0.998。血浆中Mo、Mn、Si、Rb和Sr含量与对照组比无明显差异。 相似文献
88.
F. Ide K. Mishima H. Yamada I. Saito A. Tanaka K. Kusama 《Journal of oral pathology & medicine》2007,36(8):505-510
BACKGROUND: Nevic corpuscle (NC), a stacked lamellar structure reminiscent of Meissner corpuscle, is frequently observed in dermal melanocytic nevi. Although the heading 'neurotized' is classically used for these nevi, the exact neural nature of NC has been a topic of considerable debate. Neurotized nevi have received little attention in the dental literature, and there was no information on NC in oral melanocytic nevi. METHODS: Six cases of oral intramucosal nevi with a significant number of NC (two completely and four partially neurotized nevi) were examined immunohistochemically and ultrastructurally. RESULTS: NC was composed of closely piled laminar cells devoid of visible melanin. NC and associated spindle nevus cells were immunopositive for S-100 protein but negative for HMB-45, myelin basic protein and epithelial membrane antigen. Within NC, no reactivity for neurofilament protein, protein gene product 9.5 or peripherin was evident. Numerous CD34-positive dendritic cells were located between nevus cells and often encircled NC. Ultrastructurally, NC consisted of concentrically layered elongated cells with a slender lamellated cytoplasm rich in thin filaments and pinocytotic vesicles. Their cytoplasmic processes were focally covered by external basal lamina and continuous to spindle nevus cells. Occasional NC cells contained a few melanosomes. There was no interposed axon in NC. CONCLUSIONS: Despite the close resemblance to Meissner corpuscle, NC showed no axonal supply. NC cells lacked terminal Schwannian differentiation and appeared to be modified melanocytes with some perineurial ultrastructural characteristics. The presence of CD34-positive cells, presumably corresponding to endoneurial fibroblasts, further supports an organizational relationship of NC and peripheral nerve sheath elements. 相似文献
89.
M Ishii O Abe H Okura N Okazaki T Kawai Y Saito N Sawabu Y Takamizawa T Takeuchi H Niitani 《Gan to kagaku ryoho. Cancer & chemotherapy》1987,14(8):2548-2555
The CA-50 enzyme immunoassay kit (EIA kit) that has been developed with the use of C-50 monoclonal antibody prepared by L. Lindholm et al. was evaluated for diagnosis of human cancer. The levels of CA-50 in the sera were determined using this kit supplied from Mitsui Pharmaceuticals, Inc. Co. in 759 healthy donors, 728 patients with benign disease and 1,263 untreated patients with cancer. A CA-50 concentration of 40 U/ml of serum was used as the cut-off value. Patients with pancreatic cancer and patients with bile duct cancer had high positive incidence of 75% and 68%, respectively, compared with a low positive incidence of under 40% in patients with other cancers. On the other hand, positive rates in patients with benign disease were as low as 13%. Comparison of the serum levels of CA-50 with CA19-9 in the same samples did not exhibit complete positive correlation in patients with pancreatic cancer, patients with bile duct cancer and patients with liver cancer. These findings indicated that C-50 antibody reacted with two epitopes of CA19-9 and sialosyllactotetraose. From the above results, the usefulness of CA-50 as a tumor marker for pancreatic cancer and bile duct cancer was recognized with this EIA kit. 相似文献
90.
Katsuyoshi Hori Maroh Suzuki Shigeru Tanda Sachiko Saito Mika Shinozaki Qiu-Hang Zhang 《Cancer science》1991,82(11):1309-1316
To elucidate the significance of angiotensin II (AID-induced hypertension chemotherapy, changes of tissue blood flow both in normal subcutis and in tumors (AH109A, LY80) were measured with the hydrogen gas clearance method. A newly-developed anesthetic machine was used to keep the animals' condition constant. Tissue blood flow in normal subcutis and tumors always fluctuated with time under normotension. The nature and the rate of fluctuation in tumor Wood flow were almost identical in two different types of tumors. However, the fluctuation of blood flow in tumor and that in normal subcutis were almost always inversely related when blood flows in these different tissues were measured simultaneously, i.e., when tissue blood flow in normal subcutis decreased, tumor blood flow increased, and vice versa. The findings supported the idea that the connection mode between the tumor vascular bed and normal vascular bed is a parallel circuit. Vascular resistance in the normal vascular bed under All-induced hypertension seemed to be greater than that under normotension, because the All-increased tumor blood flow always exceeded the maximum tumor blood flow under normotension. Due to the fluctuations of tumor blood flow, no-flow or low-flow areas, resistant to delivery of anti-cancer drugs, moved sporadically within the tumor under the normotensive condition. However, good conditions for drug delivery to tumor tissue were induced by All-induced hypertension. 相似文献