全文获取类型
收费全文 | 11396篇 |
免费 | 563篇 |
国内免费 | 64篇 |
专业分类
耳鼻咽喉 | 160篇 |
儿科学 | 269篇 |
妇产科学 | 151篇 |
基础医学 | 1415篇 |
口腔科学 | 258篇 |
临床医学 | 678篇 |
内科学 | 2990篇 |
皮肤病学 | 361篇 |
神经病学 | 778篇 |
特种医学 | 613篇 |
外科学 | 2029篇 |
综合类 | 47篇 |
一般理论 | 1篇 |
预防医学 | 273篇 |
眼科学 | 160篇 |
药学 | 604篇 |
中国医学 | 18篇 |
肿瘤学 | 1218篇 |
出版年
2023年 | 73篇 |
2022年 | 160篇 |
2021年 | 310篇 |
2020年 | 127篇 |
2019年 | 214篇 |
2018年 | 278篇 |
2017年 | 220篇 |
2016年 | 249篇 |
2015年 | 253篇 |
2014年 | 346篇 |
2013年 | 428篇 |
2012年 | 710篇 |
2011年 | 704篇 |
2010年 | 388篇 |
2009年 | 309篇 |
2008年 | 562篇 |
2007年 | 639篇 |
2006年 | 613篇 |
2005年 | 685篇 |
2004年 | 578篇 |
2003年 | 613篇 |
2002年 | 580篇 |
2001年 | 216篇 |
2000年 | 214篇 |
1999年 | 249篇 |
1998年 | 150篇 |
1997年 | 103篇 |
1996年 | 115篇 |
1995年 | 122篇 |
1994年 | 74篇 |
1993年 | 95篇 |
1992年 | 165篇 |
1991年 | 177篇 |
1990年 | 166篇 |
1989年 | 133篇 |
1988年 | 140篇 |
1987年 | 100篇 |
1986年 | 84篇 |
1985年 | 113篇 |
1984年 | 87篇 |
1983年 | 50篇 |
1982年 | 29篇 |
1981年 | 40篇 |
1980年 | 26篇 |
1979年 | 48篇 |
1978年 | 32篇 |
1977年 | 33篇 |
1975年 | 22篇 |
1973年 | 30篇 |
1972年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 188 毫秒
31.
Y Katayama T Umekawa Y Ishikawa M Kodama M Takada Y Katoh K Kataoka K Kohri M Iguchi T Kurita 《Nihon Hinyōkika Gakkai zasshi. The japanese journal of urology》1990,81(1):89-95
Bone mineral contents of calcium urolithiasis patients (105 males and 52 females) were measured by the microdensitometry (MD) method, and the patients were divided into the MD normal group and the MD abnormal group. The patients were also divided into the group (21 males and 3 females) treated with thiazides for 1 year or more and the nontreated group to examine various factors in blood and urine. [Nontreated group] The rate of MD abnormality was higher in younger males. The rate tended to increase with age in females. Alkaline phosphatase values were significantly higher in MD abnormal group males than in MD normal group males. Urinary calcium excretion and PTH values were significantly higher in MD abnormal group females than in MD normal group females. Comparison of hypercalciuria and normocalciuria revealed no significant difference between the MD normal rate and the MD abnormal rate. Comparison of single of stone formers and recurrent stone formers also revealed no significant difference between the MD normal rate and the MD abnormal rate. [Treated group] PTH and alkaline phosphatase values were significantly higher in the treated group than in the nontreated group. Alkaline phosphatase values were significantly higher in the MD abnormal group. From the viewpoint of stone recurrence prevention, the monitoring of bones where the majority of calcium in the body is present is considered important besides behavior of calcium in blood and urine. 相似文献
32.
K. Kohri T. Umekawa Y. Ishikawa Y. Katayama M. Kodama M. Takada Y. Katoh K. Kataoka M. Iguchi T. Kurita 《International urology and nephrology》1990,22(1):13-23
Factors relating alterations in plasma and urine composition to recurrence of urinary stones during drug therapy were investigated
by using a multiple regression analysis technique. These factors were influenced not only by the efficacy of the drugs but
also by other factors (plasma or urinary constituents and overall health of the patients, etc.). In order to study the effect
of drug therapy or other treatment on the alteration of plasma and urine constituents, multiple regression analysis is more
appropriate than Student's pairedt-test which has been used by some workers. These two analytical methods yield different results even if used on the same data. 相似文献
33.
We have shown previously that activin A increases the number of immunoreactive follicle-stimulating hormone (FSH) cells. To further investigate the action of activin A, we examined its effects on anterior pituitary cells fractionated by centrifugal elutriation. Before activin A treatment, FSH cells were widely distributed among various fractions; a higher proportion of FSH cells was found in larger cell fractions (fractions 5-9), and a lower proportion in smaller cell fractions (fractions 2-4). After culture of the cells in each fraction with activin A (10 ng/ml) for 72 h, the number of FSH cells in fraction 4 only was significantly (P less than 0.05) higher by 225% than that in cells cultured without activin A. The amount of FSH secreted into the medium was minimal or undetectable in fractions 1-4. However, FSH secretion tended to be, or was significantly (P less than 0.01 in fraction 9), stimulated by activin A in fractions 5-9, in which the numbers of FSH cells were not significantly affected. These results suggest a dual mode of action of activin A on FSH: activin A increases the number of FSH cells in a specific type(s) of middle-sized cell fraction, and stimulates FSH secretion at least from larger cells without affecting the number of FSH cells. 相似文献
34.
35.
Akihiro Hosaka M.D. Tetsuro Miyata M.D. Hiroshi Shigematsu M.D. Jun-o Deguchi M.D. Hideo Kimura M.D. Hirokazu Nagawa M.D. Osamu Sato M.D. Takehiko Sakimoto M.D. Tomoyuki Mochizuki M.D. 《Journal of gastrointestinal surgery》2006,10(4):583-585
The vascular type of Ehlers-Danlos syndrome is a genetic disorder of connective tissue and is frequently associated with catastrophic
arterial complications. Its surgical treatment is extremely difficult because of the fragility of vessels. This article describes
three patients with vascular type of Ehlers-Danlos syndrome who developed mesenteric hemorrhage due to spontaneous arterial
rupture. The clinical and molecular characteristics of the disease are briefly reviewed. 相似文献
36.
37.
Kei-ichi Katayama Masaki Ueno Hirofumi Yamauchi Hiroyuki Nakayama Kunio Doi 《Experimental and toxicologic pathology》2002,54(3):193-196
Ethylnitrosourea (ENU) is a simple alkylating agent. It induces gene mutations in fetal primordial germ cells (PGCs), and a high incidence of congenital malformations is also found in the offspring of male mice treated with ENU at the embryonic stage. It is also reported that decreases in the fertility rate and weights of the testis and ovary were found in the offspring from dams treated with ENU. In this study, we analyzed the occurrence of apoptotic cell death and the expression of p53 protein which is thought to play an important role in the DNA damage-induced apoptosis after administration of ENU to pregnant rats on day 13 of gestation to obtain a clue for clarifying the toxic effect of ENU on PGCs. Apoptotic cells increased in PGCs in fetal gonads from 3 h after treatment. The number of apoptotic PGCs peaked at 6 h and gradually decreased towards 24 h after treatment. On the other hand, p53-positive PGCs increased from I h after treatment, prior to the induction of apoptosis. The number of p53-positive PGCs peaked at 3 h and returned to the control level at 24 h after treatment. These results suggest that ENU induces apoptosis in rat fetal PGCs immediately after its administration to dams and excess cell death by apoptosis may have a close relation to the later occurrence of decreases in the fertility rate and gonadal weight. Moreover, a possible involvement of p53 is suggested in the ENU-induced apoptosis in PGCs. 相似文献
38.
Role of bacterial adherence and the mucus barrier on bacterial translocation: effects of protein malnutrition and endotoxin in rats. 总被引:7,自引:0,他引:7
下载免费PDF全文
![点击此处可从《Annals of surgery》网站下载免费的PDF全文](/ch/ext_images/free.gif)
OBJECTIVE: The purpose of the study was to investigate the potential relations between mucosal bacterial adherence, intestinal mucus and mucin content, and bacterial translocation. SUMMARY BACKGROUND DATA: The attachment of bacteria to mucosal surfaces is the initial event in the pathogenesis of most bacterial infections that originate at mucosal surfaces, such as the gut. The intestinal mucus layer appears to function as a defensive barrier limiting micro-organisms present in the intestinal lumen from colonizing enterocytes. Consequently, studies focusing on the biology of bacterial adherence to the intestinal mucosa likely are to be important in clarifying the pathogenesis of gut origin sepsis. METHODS: To explore the relations between intestinal bacterial adherence, mucus bacterial binding, and bacterial translocation, two models were used. One (protein malnutrition) in which profound alterations in intestinal morphology occurs in the absence of significant translocation and one (endotoxin challenge) in which bacterial translocation occurs and intestinal morphology is relatively normal. RESULTS: Protein malnutrition was not associated with bacterial translocation and measurement of enteroadherent, mucosally associated bacterial population levels documented that the total number of gram-negative enteric bacilli adherent to the ileum and cecum was less in the protein-malnourished rats than in the normally nourished animals (p < 0.01). Furthermore, there was an inverse relation between the duration of protein malnutrition and bacterial adherence to the intestinal mucosa (r = 0.62, p < 0.002). In contrast, after endotoxin challenge, the level of enteroadherent bacteria was increased and bacterial translocation was observed. The binding of Escherichia coli to immobilized ileal mucus in vitro was decreased significantly in protein-malnourished rats, whereas E. coli binding to insoluble ileal mucus was increased in the rats receiving endotoxin. CONCLUSIONS: This study indicates that the adherence of bacteria to the intestinal mucosal surface is an important factor in bacterial translocation, that intestinal mucus modulates bacterial adherence, and that increased levels of mucosally associated bacteria are associated with a loss intestinal barrier function to bacteria. 相似文献
39.
Noriaki Tsubota Masahiro Myoshimura Akihiro Murotani Yoshifumi Miyamoto Yasumi Matoba 《Surgery today》1994,24(11):978-981
The results of 101 consecutive bronchoplasties performed between 1979 and 1993, including 8 cases of pneumonectomy, 88 cases of lobectomy, 3 cases of segmentectomy, and 2 cases of bronchial resection, are herein reported. Squamous cell carcinoma was the most common disease (59%) followed by adenocarcinoma (30%) and other diseases (11%). Anastomosis was satisfactory in 96 cases. Among the five stenosed cases, local recurrence was found in two cases, and there were three benign strictures. Two of the three benign strictures were treated with bouginage. The pulmonary artery was concomitantly reconstructed in seven cases with satisfactory results. Preoperative chemoradiotherapy was performed in 15 advanced cases and was followed by acceptable surgical results. The 5-year survival rate, according to the post-operative staging of the 86 patients without induction therapy, was 86% in stage I (19 patients), 49% in stage II (21 patients), and 27% in stage IIIA (40 patients). The overall survival rate was 46% at 5 years. There were two indications for this procedure i.e., a positive resection margin in 59 cases and positive hilar nodes in 42 cases. Better survival was noted in patients with squamous cell carcinoma, stage I, and surgery was thus selected for a positive resection margin, and not for a positive node. 相似文献
40.
Akihiro Hagiwara Masashi Sano Emiko Asakawa Hikaru Tanaka Ryohei Hasegawa Nobuyuki Ito 《Cancer science》1992,83(9):949-954
The modifying potential of two nephrotoxic agents, harman and norharman, on N-ethyl-N-hydroxyethylnitrosamine (EHEN)-induced renal and hepatic carcinogenesis was investigated in male F344/DuCrj rats. Animals were given 0.1% EHEN in their drinking water for the first 2 weeks as an initiator. Subsequently, starting 3 weeks from the commencement, they were fed diet containing these compounds at concentrations of 1000, S00 or 0 ppm until week 26, and then killed for light microscopic examination. The mean numbers of renal tubular cell hyperplasias/cm2 and those of tumors/cm2 in rats given harman and norharman at 1000 ppm after initiation, but not at 500 ppm, were significantly increased as compared to the control values. However, neither compound modified liver carcinogenesis. It is concluded that harman and norharman show enhancing effects on rat kidney carcinogenesis, when ingested at dose levels which cause renal tubular damage. 相似文献