全文获取类型
收费全文 | 43778篇 |
免费 | 2293篇 |
国内免费 | 172篇 |
专业分类
耳鼻咽喉 | 544篇 |
儿科学 | 791篇 |
妇产科学 | 524篇 |
基础医学 | 5741篇 |
口腔科学 | 2075篇 |
临床医学 | 3221篇 |
内科学 | 9642篇 |
皮肤病学 | 925篇 |
神经病学 | 4066篇 |
特种医学 | 2096篇 |
外国民族医学 | 2篇 |
外科学 | 6631篇 |
综合类 | 199篇 |
一般理论 | 7篇 |
预防医学 | 1656篇 |
眼科学 | 947篇 |
药学 | 2813篇 |
中国医学 | 125篇 |
肿瘤学 | 4238篇 |
出版年
2023年 | 225篇 |
2022年 | 258篇 |
2021年 | 868篇 |
2020年 | 513篇 |
2019年 | 659篇 |
2018年 | 855篇 |
2017年 | 656篇 |
2016年 | 811篇 |
2015年 | 870篇 |
2014年 | 1141篇 |
2013年 | 1366篇 |
2012年 | 2288篇 |
2011年 | 2376篇 |
2010年 | 1428篇 |
2009年 | 1202篇 |
2008年 | 2005篇 |
2007年 | 2289篇 |
2006年 | 2118篇 |
2005年 | 1929篇 |
2004年 | 1935篇 |
2003年 | 1754篇 |
2002年 | 1742篇 |
2001年 | 1378篇 |
2000年 | 1469篇 |
1999年 | 1331篇 |
1998年 | 509篇 |
1997年 | 414篇 |
1996年 | 386篇 |
1995年 | 316篇 |
1994年 | 322篇 |
1993年 | 298篇 |
1992年 | 1016篇 |
1991年 | 867篇 |
1990年 | 831篇 |
1989年 | 832篇 |
1988年 | 792篇 |
1987年 | 785篇 |
1986年 | 699篇 |
1985年 | 642篇 |
1984年 | 451篇 |
1983年 | 362篇 |
1979年 | 317篇 |
1978年 | 213篇 |
1977年 | 188篇 |
1974年 | 203篇 |
1973年 | 172篇 |
1972年 | 173篇 |
1971年 | 190篇 |
1970年 | 162篇 |
1969年 | 184篇 |
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
91.
Naoko Masuzawa Mitsuo Kishimoto Yoshiki Takahashi 《International journal of gynecological pathology》2003,22(3):285-288
A 57-year-old female presented with an abnormal Pap smear. Colposcopic examination of the cervix revealed white mucosa with erosion and several areas of black pigmentation. After a colposcopically directed biopsy and loop conization, radical hysterectomy and bilateral salpingo-oophorectomy with pelvic and paraaortic lymphadenectomy were performed. Pathological examination disclosed an invasive squamous cell carcinoma admixed with many dendritic melanocytes. Melanin granules were present within the melanocytes and tumor cells. Although similar tumors have been reported in other sites, this is the first report to our knowledge of a pigmented squamous cell carcinoma of the uterine cervix. 相似文献
92.
Naoya Katsuragi Yutsuki Nakajima Yuji Shiraishi Masahiro Hashizume Nobumasa Takahashi 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2005,53(8):440-442
We describe a case of a large bronchial fistula and empyema after right upper lobectomy that was treated successfully with
open window thoracostomy followed by a latissimus dorsi myocutaneous flap and limited thoracoplasty. A latissimus dorsi myocutaneous
flap can provide immediate airtight closure of a large bronchial fistula, allowing lavage and curettage of the empyema cavity
to reduce the chance of postoperative infection. An important aspect of this technique is that the deepithelialized skin side
rather than muscle is sutured to an opening of the bronchus. As compared with other techniques, a latissimus dorsi myocutaneous
flap is superior in that it requires a single incision and does not require an intraop-erative change of position. In addition,
the technique causes little dysfunction of the chest and shoulder and preserves the vascular supply to ensure the viability
of the flap even if it was divided in a previous operation. 相似文献
93.
Melaine de Almeida Lawall Marcelo Macedo Crivelini 《Journal of applied oral science : revista FOB》2006,14(4):276-280
Leukoplakias are oral lesions that may have many clinical and histological aspects and they are usually associated with malignancy when dysplastic alterations are shown. However, these transformations may occur in non-dysplastic lesions that show harmless clinical aspect. For this reason, the proposal was to study the p53 and PCNA immunohistochemical expression in non-dysplastic leukoplakias, trying to correlate the results only with the epithelial keratinization degree. For this, 24 leukoplakias degrees I, II and III of Grinspan were used, all of them located in oral mucosa. Most of the leukoplakias showed p53 and PCNA expression in their different keratinization degrees. The p53 marking was confined to the basal and parabasal layers, while the PCNA marking occurred in practically all epithelial layers. The expression pattern of these markers was histologically and statistically similar between the lesions with these keratinization variations. It was evident that non-dysplastic epithelium of leukoplakias showed submicroscopical signs of alterations that lead to malignant transformation, and that the keratinization degree did not correlate to a greater risk of this event. 相似文献
94.
95.
Andr ia Kist Fernandes Felipe Mallmann Ana Maria Pasquali Steinhorst Fernando Lopes Nogueira Eduardo Mü ller vila Dumitriu Zunino Saucedo Francisco Juchem Machado Marcelo Greg rio Raymundi S rgio Saldanha Menna Barreto Paulo de Tarso Roth Dalcin 《The Journal of asthma》2003,40(6):683-690
Asthma patients that depend on emergency department (ED) services are generally considered to have extremely poor disease control and prognosis. It is important to identify characteristics related to poor disease control and frequent visits to the ED to apply appropriate clinical management. This study comprised a cross-sectional survey of consecutive patients with asthma exacerbation (age ≥12 years) presenting at the adult ED of a large, tertiary care, university-affiliated hospital over a 2-month period. The frequent visitors (FV) were defined by ≥3 visits to the ED in the preceding year, and the occasional visitors (OV) by ≤2 visits. Eighty-six patients (61 females and 25 males) were included in the study (mean age 38 ± 18 years). Of these patients, 51.2% were FV and 48.8% were OV. Sixty-nine percent had annual income lower than A$3000 and 66.3% had ≤8 years of the formal education. Only 18.6% had used inhaled corticosteroids, 79.1% identified the asthma attack severity, 70.9% increased or initiated inhaled β-agonist, 20.9% increased or initiated steroid therapy, and 55.8% had an asthma action plan for attack. The number of hospital admissions in past year (OR 4.3, P = .02), use of home nebulizer (OR 3.6, P = .05) and the lack of a written asthma action plan (OR 3.3, P = .03) were independently associated with frequent visits to the ED. We conclude that a substantial proportion of the patients that visit the ED are FV. These patients are more likely to have hospital admission in the past year, to use a home nebulizer, and to lack a written asthma action plan. They should be considered the most important target for asthma education. 相似文献
96.
p53 mutations in non-small cell lung cancer in Japan: association between mutations and smoking. 总被引:20,自引:0,他引:20
H Suzuki T Takahashi T Kuroishi M Suyama Y Ariyoshi T Takahashi R Ueda 《Cancer research》1992,52(3):734-736
The p53 gene has been implicated as a tumor suppressor gene involved in the pathogenesis of lung cancer. Our previous study revealed that the p53 gene is frequently mutated with a distinct nucleotide substitution pattern in small cell lung cancer specimens in Japanese patients. In this study, we examined 30 primary, resected non-small cell lung cancer samples in Japanese patients using complementary DNA-polymerase chain reaction and sequencing. Mutations changing the p53 coding sequence were found in 14 of 30 tumor samples (47%), while G:C to T:A transversions which are uncommon in other cancers such as colon cancer were the most frequently observed mutations, in agreement with an earlier report on non-small cell lung cancer in American patients. Furthermore, the present study shows for the first time that in univariate and multivariate analyses, the presence of p53 mutations is closely associated with lifetime cigarette consumption. 相似文献
97.
98.
A Nishikawa F Furukawa M Mitsui T Enami T Kawanishi T Hasegawa M Takahashi 《Carcinogenesis》1992,13(7):1155-1158
The effects of calcium chloride on glandular stomach carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and sodium chloride were investigated in male outbred Wistar rats. Animals were given MNNG solution (100 p.p.m.) as drinking water and simultaneously fed a diet supplemented with 5% sodium chloride for 8 weeks. Matched negative controls received neither MNNG nor sodium chloride. Rats were then fed basal diet and given calcium chloride solution (1 or 0.2%) or tap water for the following 52 weeks. The incidences and multiplicities of preneoplastic hyperplasias in the glandular stomachs of rats given MNNG/sodium chloride followed by 1 and 0.2% calcium chloride were significantly lower than those in rats given MNNG/sodium chloride alone. The inhibitory effects of calcium were exerted in a dose-dependent manner. Calcium treatment also showed a tendency to inhibit the development of gastric adenocarcinomas although this was not statistically significant. Rats without carcinogen treatment had neither carcinomas nor preneoplastic hyperplasias in the glandular stomach. Calcium intake also significantly reduced the levels of malondialdehyde, a measure of lipid peroxidation, in the gastric mucosa and urine, the former in a dose-dependent manner. Thus, calcium chloride exerted inhibitory effects when given during the post-initiation phase of two-stage glandular stomach carcinogenesis in rats. 相似文献
99.
Epirubicin is equivalent to adriamycin in vitro against many cancer cells but more effective against gastric cancer cells. 总被引:1,自引:0,他引:1
We compared the cytotoxic effects of two anthracycline derivatives, epirubicin (EPI) and adriamycin (ADM), against human tumor cells in vitro. Various tumor specimens, obtained at surgery, included 57 liver, 19 lung, 16 gastric, 10 colorectal and 7 breast cancer specimens. These tumor cells were exposed to the same concentration of EPI or ADM for 3 days. The chemosensitivity of each tumor cell type to each drug was then assayed using the in vitro succinate dehydrogenase inhibition (SDI) test. Sensitivity to the treatment was defined as a 50% or greater reduction in the succinate dehydrogenase (SD) activity of the tumor cells, relative to that of the control (untreated) cells. Each cell type, except for gastric cancer cells, was equally sensitive to EPI and ADM. Gastric cancer cells were more sensitive to EPI than to ADM (P less than 0.05). The rate of coincidence, the sum of the co-sensitive and co-resistant rates of all the tumors, was quite high (90.8%). Thus, these findings indicate that EPI and ADM are equally cytotoxic to each tumor cell type, but EPI is more cytotoxic than ADM to gastric cancer cells. Since EPI is reported to be less cardiotoxic than ADM, EPI may replace ADM in cancer chemotherapy. 相似文献
100.
A Nishikawa F Furukawa T Imazawa H Yoshimura K Mitsumori M Takahashi 《Carcinogenesis》1992,13(8):1379-1382
The modulating effects of caffeine, nicotine, ethanol and sodium selenite on development of N-nitrosobis(2-oxopropyl)-amine (BOP)-initiated pancreatic tumors were investigated. Female Syrian golden hamsters were given s.c. injections of BOP (10 mg/kg body weight) or saline alone once a week for 3 weeks and then administered 2000 p.p.m. caffeine, 25 p.p.m. nicotine, 20% ethanol or 4 p.p.m. sodium selenite in their drinking water for the next 37 weeks. Control animals were given tap water alone after BOP initiation. Only the BOP-treated groups developed pancreatic adenocarcinomas and dysplasias. The multiplicity of pancreatic carcinomas was significantly higher (P less than 0.05) in animals receiving caffeine than in the controls. In addition, caffeine treatment slightly increased the incidence of carcinomas. Nicotine and ethanol also showed tendencies to enhance pancreatic carcinogenesis, although there were statistically no significant differences regarding lesion development. In contrast, sodium selenite administration was associated with a tendency for a decrease in the number of carcinomas and dysplasias. Thus, among these chemicals of obvious significance to human life-style, caffeine enhanced the development of pancreatic tumors when administered during the post-initiation phase in this hamster model. 相似文献