全文获取类型
收费全文 | 16823篇 |
免费 | 1394篇 |
国内免费 | 315篇 |
专业分类
耳鼻咽喉 | 162篇 |
儿科学 | 445篇 |
妇产科学 | 436篇 |
基础医学 | 1917篇 |
口腔科学 | 417篇 |
临床医学 | 1684篇 |
内科学 | 3277篇 |
皮肤病学 | 203篇 |
神经病学 | 1130篇 |
特种医学 | 735篇 |
外国民族医学 | 1篇 |
外科学 | 2591篇 |
综合类 | 766篇 |
现状与发展 | 2篇 |
一般理论 | 16篇 |
预防医学 | 1418篇 |
眼科学 | 374篇 |
药学 | 1371篇 |
1篇 | |
中国医学 | 280篇 |
肿瘤学 | 1306篇 |
出版年
2023年 | 174篇 |
2022年 | 275篇 |
2021年 | 509篇 |
2020年 | 406篇 |
2019年 | 457篇 |
2018年 | 490篇 |
2017年 | 424篇 |
2016年 | 511篇 |
2015年 | 520篇 |
2014年 | 695篇 |
2013年 | 841篇 |
2012年 | 1250篇 |
2011年 | 1372篇 |
2010年 | 792篇 |
2009年 | 733篇 |
2008年 | 1024篇 |
2007年 | 1048篇 |
2006年 | 973篇 |
2005年 | 926篇 |
2004年 | 771篇 |
2003年 | 698篇 |
2002年 | 691篇 |
2001年 | 357篇 |
2000年 | 295篇 |
1999年 | 249篇 |
1998年 | 152篇 |
1997年 | 102篇 |
1996年 | 95篇 |
1995年 | 80篇 |
1994年 | 71篇 |
1993年 | 71篇 |
1992年 | 137篇 |
1991年 | 117篇 |
1990年 | 109篇 |
1989年 | 105篇 |
1988年 | 98篇 |
1987年 | 120篇 |
1986年 | 108篇 |
1985年 | 93篇 |
1984年 | 64篇 |
1983年 | 53篇 |
1982年 | 38篇 |
1981年 | 37篇 |
1980年 | 29篇 |
1979年 | 56篇 |
1978年 | 41篇 |
1977年 | 34篇 |
1975年 | 24篇 |
1974年 | 29篇 |
1970年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Keita AD Dembélé M Kané M Fongoro S Traoré M Sacko M Diallo S Sidibe S Traoré HA Doumbo O Traoré I 《Bulletin de la Societe de pathologie exotique (1990)》2001,94(4):335-338
Urinary bilharziasis is a parasitic infection responsible for vesical, urethral and renal lesions. The authors demonstrate the importance of ambulatory echography on a large scale and describe various echographic lesions. Vesical attacks occurred in 27% of the wall irregularity, 44% of the masses and polyps. Pyelic and urethral abnormalities occurred in 16.6% and 29.9% of cases respectively at the baseline in 1991. These prevalence rates decreased after seven years, in 1998. The authors discuss the utility of chemotherapy with praziquantel and the necessity of a periodical mass treatment in the areas with high bilharziasis endemicity in Mali. 相似文献
32.
Tang NL Hui J Law LK Lam YY Chan KY Yeung WL Chan AY Cheung KL Fok TF 《Human mutation》2000,16(5):446
Glutaric acidemia type I is caused by mutations of the glutaryl-CoA dehydrogenase (GCDH) gene resulting in loss of GCDH enzyme activity. Patients present with progressive dystonia and lesions in basal ganglia. Dietary treatment, when instituted from the early neonatal period, markedly reduces dystonia and morbidity. Early diagnosis and prenatal diagnosis will be facilitated by knowledge of locally prevalent GCDH mutations. Several common GCDH mutations have been found in different ethnic groups. GCDH mutations were studied in 5 Chinese glutaric acidemia type I families. We detected two novel recurrent mutations (A219T and IVS10-2A>C) which were found in two unrelated families. An asymptomatic carrier of IVS10-2A>C was also found on screening of 120 individuals. Other mutations were identified, including two other novel (R386G & IVS3+1G>A) and two known mutations (G178R & R355H). Fibroblasts from patients carrying the novel mutations were confirmed to be deficient for GCDH activity. This is the first report of GCDH mutations describing recurrent mutations in Chinese patients. The carrier rate of IVS10-2A>C may be particularly high in Chinese. 相似文献
33.
A case of clear cell chondrosarcoma in a Chinese patient is described. The clear cells showed strongly positive S-100 protein immunoreactivity. Ultrastructurally 2 types of chondroid cells were demonstrated. One type appeared more primitive with abundant electron-lucent cytoplasm and sparse organelles. The other type of cell was more differentiated with presence of microvilli and numerous dilated cisternae of endoplasmic reticulum. Previous ultrastructural studies on these lesions were reviewed and compared with the present findings. 相似文献
34.
35.
36.
Effects of the ion-channel blocker quinine on human sperm volume, kinematics and mucus penetration, and the involvement of potassium channels 总被引:5,自引:0,他引:5
Sperm defects in the infertile c-ros knockout mouse model have recently highlighted the importance of volume regulation in sperm function. In this study, washed human spermatozoa were shown to change size and shape, as detected by flow cytometry and light microscopy, in response to the ion-channel blocker quinine (minimum effective doses at 20 and 125 micromol/l respectively). The increase in sperm volume was accompanied by reduced straight-line velocity (VSL) and linearity (LIN) of the swim-path but increased lateral head displacement and curvilinear velocity, while percentage motility was unaffected. Spermatozoa in semen and in artificial cervical mucus were similarly affected at 0.2 and 0.5 mmol/l quinine, resulting in marked reduction of mucus penetration and migration. The effects of quinine on sperm volume and kinematics were reduced or abolished by the K(+)-ionophores valinomycin (1 and 5 micromol/l) and gramicidin (0.5 and 1 micromol/l). In Ca(2+)-free medium; however, the quinine effects largely persisted. The K(+)-channel blocker, 4-aminopyridine (1 and 4 mmol/l), mimicked the quinine effects in the reduction of VSL and LIN, while the K(+)-channel blocker, tetraethylammonium chloride (TEA, 2.5-10 mmol/l), did not affect kinematics. The K(+)-channel (Kv1.3)-specific inhibitor, margatoxin, and the Ca(2+)-dependent K(+)-channel blocker, charybdotoxin, also had no effects. This study suggests that volume regulation in human spermatozoa and the linear trajectory of their motion may rely on quinine-sensitive and TEA-insensitive, largely calcium-independent, potassium channels, and possibly volume-sensitive organic anion channels. These channels could be targets for contraception. 相似文献
37.
Wong N Hui AB Fan B Lo KW Pang E Leung SF Huang DP Johnson PJ 《Cancer Genetics and Cytogenetics》2003,140(2):124-132
Nasopharyngeal carcinoma (NPC) cell lines and xenografts represent valuable models for functional and therapeutic studies on this common malignancy in Southeast Asia. The karyotypic information in most NPC cell lines and xenografts, however, remains largely unclear to date. We have characterized the chromosomal aberrations in six commonly used human NPC cell lines and xenografts using the molecular cytogenetic technique of comparative genomic hybridization (CGH). Genomic imbalances identified in cell lines were further correlated with structural abnormalities indicated from spectral karyotyping (SKY) analysis. CGH revealed consistent overrepresentations of 8q (six out of six cases) with a smallest overlapping region identified on 8q21.1q22. Other common gains included 7p (4/6 cases), 7q (4/6 cases), 12q (4/6), and 20q (4/6 cases), where minimal overlapping regions were suggested on 7p15p14, 7q11.2q21, and 12q22q24.1. Common losses were detected on 3p12p21 (4/6 cases) and 11q14qter (4/6 cases). Although SKY analysis on cell lines revealed predominantly unbalanced rearrangements, reciprocal translocations that involved chromosome 2 [i.e., t(1;2), t(2;3), and t(2;4)] were suggested. Furthermore, SKY examination illustrated additional breakpoints on a number of apparently balanced chromosomes. These breakpoints included 3p21, 3q26, 5q31, 6p21.1p25, 7p14p22, and 8q22. Our finding of regional gains and losses and breakpoints represents information that may contribute to NPC studies in vitro. 相似文献
38.
Radiation proctitis is a frequent acute complication encountered with pelvic irradiation. This study was aimed at establishing the optimal radiation dose for radiation-induced proctitis in rats. Female Wistar rats were used. The rectal specimens were examined morphologically at 5th and 10th day following 10-30 Gy irradiation in single fraction. With increasing dose, mucosal damage became worse, and there was a prominent reaction after > or =15 Gy. We selected 17.5 Gy as an optimal dose for radiation proctitis and examined specimens at day 1-14 and at week 4, 6, 8, and 12 after 17.5 Gy. The rectal mucosa revealed characteristic histological changes with time. An edema in lamina propria started as early as 1-2 days after irradiation and progressed into acute inflammation. On day 7 and 8, regeneration was observed with or without ulcer. Four weeks later, all regeneration processes have been completed with end result of either fibrosis or normal appearing mucosa. This study showed that the radiation injury of the rectum in rat develops in dose-dependent manner as it has reported in previous studies and suggested that 17.5 Gy in single fraction is the optimum dose to evaluate the protective effect of various medications for radiation proctitis in face of the clinical situation. 相似文献
39.
Gong X Yeung ES 《Journal of chromatography. B, Biomedical sciences and applications》2000,741(1):15-21
Current high-throughput approaches to the analysis of PCR products are based primarily on electrophoretic separation and laser-excited fluorescence detection. We show that capillary array electrophoresis can be applied to HIV-1 diagnosis and D1S80 VNTR genetic typing based simply on UV absorption detection. The additive contribution of each base pair to the total absorption signal provides adequate detection sensitivity for analyzing most PCR products. Not only is the use of specialized and potentially toxic fluorescent labels eliminated, but also the complexity and cost of the instrumentation are greatly reduced. 相似文献
40.
Follicular fluid renin concentration and IVF outcome 总被引:1,自引:0,他引:1
C M Cornwallis S L Skinner P L Nayudu A Lopata R L Thatcher S P Yeung J A Whitworth 《Human reproduction (Oxford, England)》1990,5(4):413-417
Total renin protein concentration (TRC) was measured in stored follicular fluid (FF) samples from 42 women. Samples were selected according to their origin from follicles either without recovered ova ('empty', n = 38) or fertilized but with failed implantation ('failed', n = 36) or successful deliveries ('deliveries', n = 71). Ratios of number of embryos transferred to number of infants delivered were 2:1, 3:1 or 4:2 but 1:1 was not available. Non-parametric testing was applied to FF-TRC, volume and outcome. TRC was significantly higher in the delivery than the failed (P = 0.001) or empty (P = 0.002) categories. Assuming that the range of renin in failed follicles can identify the sub-population of unsuccessful follicles in the delivery category, then elevated FF-TRC was clearly associated with successful outcome. For individual women, the odds of infant delivery increased 17-fold as a function of average FF-TRC between 10,000 and 25,000 microIU/ml. For failed and delivery but not empty follicles, higher renin levels occurred in the smaller follicles, consistent with a burst of renin synthesis associated with the presence of an oocyte. The results suggest that FF-TRC relates to ovum viability with ovarian hyperstimulation and may have predictive use in IVF programmes. 相似文献