全文获取类型
收费全文 | 7666篇 |
免费 | 297篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 93篇 |
儿科学 | 311篇 |
妇产科学 | 74篇 |
基础医学 | 1096篇 |
口腔科学 | 86篇 |
临床医学 | 497篇 |
内科学 | 1722篇 |
皮肤病学 | 126篇 |
神经病学 | 631篇 |
特种医学 | 241篇 |
外科学 | 1198篇 |
综合类 | 21篇 |
一般理论 | 1篇 |
预防医学 | 185篇 |
眼科学 | 112篇 |
药学 | 632篇 |
中国医学 | 25篇 |
肿瘤学 | 956篇 |
出版年
2023年 | 43篇 |
2022年 | 89篇 |
2021年 | 146篇 |
2020年 | 104篇 |
2019年 | 110篇 |
2018年 | 147篇 |
2017年 | 146篇 |
2016年 | 141篇 |
2015年 | 145篇 |
2014年 | 206篇 |
2013年 | 242篇 |
2012年 | 403篇 |
2011年 | 509篇 |
2010年 | 313篇 |
2009年 | 284篇 |
2008年 | 445篇 |
2007年 | 464篇 |
2006年 | 479篇 |
2005年 | 523篇 |
2004年 | 520篇 |
2003年 | 507篇 |
2002年 | 429篇 |
2001年 | 99篇 |
2000年 | 94篇 |
1999年 | 101篇 |
1998年 | 122篇 |
1997年 | 95篇 |
1996年 | 80篇 |
1995年 | 86篇 |
1994年 | 70篇 |
1993年 | 80篇 |
1992年 | 78篇 |
1991年 | 54篇 |
1990年 | 65篇 |
1989年 | 78篇 |
1988年 | 76篇 |
1987年 | 44篇 |
1986年 | 36篇 |
1985年 | 42篇 |
1984年 | 44篇 |
1983年 | 37篇 |
1982年 | 30篇 |
1981年 | 23篇 |
1980年 | 15篇 |
1979年 | 25篇 |
1978年 | 28篇 |
1977年 | 15篇 |
1976年 | 14篇 |
1975年 | 10篇 |
1969年 | 11篇 |
排序方式: 共有8007条查询结果,搜索用时 15 毫秒
11.
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
12.
Hiroaki Yuasa Koji Kawanishi Jun Watanabe 《The Journal of pharmacy and pharmacology》1995,47(7):576-580
The effects of ageing on the oral (gastrointestinal) absorption of d -xylose were investigated by analysing the gastrointestinal disposition after oral administration to young (9 weeks) and old (53 weeks) rats. A linear model assuming first-order gastric emptying followed by first-order intestinal absorption was fitted to remaining fraction vs time profiles for the stomach and small intestine to estimate the gastric emptying rate constant (kg) and the intestinal absorption rate constant (ka). In young and old rats, kg values were 0·087 ± 0·008 and 0·070 ± 0·007 min?1, respectively, and ka values were 0·020 ± 0·002 and 0·018 ± 0·002 min?1 suggesting an insignificant effect on ageing on the rate of oral absorption. The average intestinal lumen volume (Vav) was unchanged with ageing, and so was the apparent intestinal membrane permeability clearance (CLapp) as the product of ka and Vav. However, the small intestinal transit time (Tsi) was suggested to be twice that in older rats (171 min) than in young rats (78 min) by the analysis of gastrointestinal disposition of inulin, a non-absorbable marker. It was also shown that our preceding finding of an increase in the fraction absorbed of D-xylose with ageing can be solely ascribable to the delay in intestinal transit. Thus, among various determinants of oral absorption, only Tsi was found to be altered with ageing. The CLa,app and ka of passively absorbed drugs such as D-xylose may be generally unchanged, and the fraction absorbed may increase with ageing by the delay in intestinal transit. 相似文献
13.
Seishi Inoue Tadayasu Shono Mieko Shono Masayuki Azuma Toshiaki Hirabayashi Oshi Inagaki Hidetaro Mori Yoshikazu Fujita 《Journal of bone and mineral metabolism》1990,8(3):19-23
A case of polycythemia vera complicated by chronic renal failure under maintenance hemodialysis requiring parathyroidectory
(PTH) for secondary hyperparathyroidism (2° HPT) is reported.
A 62 year old female presented with 75000 white blood cells (WBC)/μl, 703×104 red blood cells (RBC)/μl, 23×104 platelets (PLT)/μl, hyperuricemia and hypertension in 1970 and the diagnosis of polycythemia vera was made. Hemodialysis
was started in October 1974 for chronic renal failure. Blood cells in peripheral blood rapidly decreased in number after the
beginning of dialysis, reaching the level of 10000∼20000 WBC/μl, and 150∼250×104RBC/μl. In August 1988, marked bone resorption in X-ray picture and high serum alkaline phosphatase and parathyroid hormone
(PTH) noted along with 17400 WBC/μl, 370×104RBC/μl and 35.9×104PLT/μl.
After subtotal PTX removing 3.21g parathyroid gland, serum PTH rapidly fell. At 3 months after PTX, WBC rose to 23600/μl,
RBC 372×104/μl and PLT 94.0×104/μl. At 6 months, WBC was to 31000/μl, RBC 429×104/μl and PLT 78.0×104/μl, suggesting an inhibitory action of PTH on not only RBC, but also WBC and PLT. 相似文献
14.
We studied choline acetyltransferase (CAT) activity in a rat model of brachial plexus injury. In experiment 1, we found that the CAT activity was remarkably high in the anterior roots and low in the posterior roots. In experiment 2, nerve root segments were extracted and examined for CAT activity in the root avulsion group (group A) and the plexus severance group (group B). CAT activity decreased day by day in group A, reaching about 1/20 of the normal 5 days postoperatively. By contrast, in group B activity decreased only slightly, and even at 90 days postoperatively was about 6,000 cpm (one-half normal level). As a result, CAT activity enabled us to distinghish postganglionic from preganglionic injury of the cervical roots. Furthermore, it was a useful adjunct for minimizing nerve loss in intercostal nerve transfer, distinguishing motor and sensory branches of the intercostal nerve, and evaluating the motor nerve activity. © 1995 Wiley-Liss, Inc. 相似文献
15.
Association of Vascular Endothelial Growth Factor Expression with Tumor Angiogenesis and with Early Relapse in Primary Breast Cancer 总被引:10,自引:0,他引:10
Masakazu Toi Seigo Hoshina Toshiaki Takayanagi Takeshi Tominaga 《Cancer science》1994,85(10):1045-1049
Angiogenesis is an independent prognostic indicator in breast cancer. In this report, the relationship between expression of vascular endothclial growth factor (VEGF; a selective mitogen for endothelial cells) and the microvessel density was examined in 103 primary breast cancers. The expression of VEGF was evaluated by immunocytochemical staining using anti-VEGF antibody. The microvessel density, which was determined by immunostaining for factor VIII antigen, in VEGF-rich tumors was clearly higher than that in VEGF-poor tumors ( P <0.01). There was a good correlation between VEGF expression and the increment of microvessel density. Furthermore, postoperative survey demonstrated that the relapse-free survival rate of VEGF-rich tumors was significantly worse than that of VEGF-poor tumors. It was suggested that the expression of VEGF is closely associated with the promotion of angiogenesis and with early relapse in primary breast cancer. 相似文献
16.
Seietsu Nyui Hiroyuki Osanai Hideji Masuoka Shigeri Ohba Toshiaki Ebata Yukinari Yoshida Hideki Hoshi Yoshifumi Shinohara 《Surgery today》1997,27(4):349-352
Primary extranodal malignant lymphoma frequently occurs in the gastrointestinal tract; however, it is rarely encountered in the rectum. We report herein the case of an 85-year-old man who underwent abdominoperineal resection for primary malignant lymphoma of the rectum, and 1 year later, developed hematemesis caused by gastric metastasis. To our knowledge this is the first case report of such distant metastasis developing from malignant lymphoma of the rectum. 相似文献
17.
Takashi Ishimori Satoru Nakano Masahiro Kagawa Koiku Yokoe Tarou Togami Hirofumi Asakura Toshiaki Kusuhara Motoomi Ohkawa Syeigo Nagao Yuichi Yamashita Satoshi Sugiura 《Magnetic resonance in medical sciences》2003,2(3):145-149
Three-dimensional fast asymmetric spin echo (3D FASE) cisternography provides high spatial resolution and excellent contrast as a water image acquisition technique. It is also useful for the evaluation of various anatomical regions. This study investigated the usefulness and limitations of virtual endoscopic images obtained by 3D FASE MR cisternography in the preoperative evaluation of patients with neurovascular compression. The study included 12 patients with neurovascular compression: 10 with hemifacial spasm and two with trigeminal neuralgia. The diagnosis was surgically confirmed in all patients. The virtual endoscopic images obtained were judged to be of acceptable quality for interpretation in all cases. The areas of compression identified in preoperative diagnosis with virtual endoscopic images showed good agreement with those observed from surgery, except in one case in which the common trunk of the anterior inferior cerebellar artery and posterior inferior cerebellar artery (AICA-PICA) bifurcated near the root exit zone of the facial nerve. The veins are displayed in some cases but not in others. The main advantage of generating virtual endoscopic images is that such images can be used for surgical simulation, allowing the neurosurgeon to perform surgical procedures with greater confidence. 相似文献
18.
Light microscopy of GTP-binding protein (Go) immunoreactivity within the retina of different vertebrates 总被引:2,自引:0,他引:2
Toshio Terashima Toshiaki Katada Eikichi Okada Michio Ui Yoshiro Inoue 《Brain research》1987,436(2):384-389
To examine species differences in the distribution pattern of guanosine triphosphate (GTP)-binding protein (Go) within the vertebrate retina, paraffin-embedded retinae from a number of vertebrate species, including the goldfish, frog, turtle, chicken, monkey, and human, were immunohistochemically stained with affinity-purified antibody against the alpha-subunit of Go. Go-immunoreactive products were found to be located in the neuropil, but not in the cell bodies of neurons, in the retina of all these species. However, some species differences were observed. In the frog, monkey and human, the inner plexiform layer (IPL) was homogeneously stained with this antibody, but in the goldfish, turtle and chicken, the IPL was heterogeneously stained. In the frog, chicken, turtle and human, the outer plexiform layer (OPL) was densely stained with this antibody, but in the goldfish and monkey, the OPL was rather faintly immunoreactive to the antibody. In the goldfish, monkey and human, the outer nuclear layer (ONL) was not immunoreactive to the Go-antibody, whereas in the frog, turtle and chicken, the ONL was immunoreactive to it. The implications of these species differences in Go localization in the vertebrate retina are discussed. 相似文献
19.
20.
Koibuchi Yukio; Iino Yuichi; Joshita Takashi; Yokoe Takao; Shinkai Hiroko; Kawashima Kenji; Kobayash Junya; Tanaka Sunao; Oyama Tetsunari; Hikino Toshiaki; Morishita Yasuo 《Japanese journal of clinical oncology》1995,25(6):273-277
A 66-year-old woman time of 10 days. One month after radicalmastectomy, there was local recurrence, followed by multiplepulmonary metastases, and the patient died of respiratory failure5 months after surgery. The gray-white-colored tumor measured13x12x;10 cm, and its border was well defined. The tumor wascomposed of diffusely growing round or polygonal cells withvesicular nuclei, prominent nucleoli, and ample cytoplasm containingeosinophilic inclusions. Lymph node involvement was widespread.Both vimentin and keratin were clearly demonstrated by immunohistochemicalstaining. Ultrastructural studies revealed that the MRT cellscontained cytoplasmic whorls of intermediate filaments. 相似文献