全文获取类型
收费全文 | 13878篇 |
免费 | 746篇 |
国内免费 | 111篇 |
专业分类
耳鼻咽喉 | 239篇 |
儿科学 | 297篇 |
妇产科学 | 352篇 |
基础医学 | 2017篇 |
口腔科学 | 517篇 |
临床医学 | 942篇 |
内科学 | 3293篇 |
皮肤病学 | 395篇 |
神经病学 | 1111篇 |
特种医学 | 391篇 |
外科学 | 2148篇 |
综合类 | 52篇 |
预防医学 | 706篇 |
眼科学 | 218篇 |
药学 | 859篇 |
中国医学 | 53篇 |
肿瘤学 | 1145篇 |
出版年
2023年 | 82篇 |
2022年 | 209篇 |
2021年 | 353篇 |
2020年 | 202篇 |
2019年 | 308篇 |
2018年 | 363篇 |
2017年 | 286篇 |
2016年 | 343篇 |
2015年 | 410篇 |
2014年 | 553篇 |
2013年 | 625篇 |
2012年 | 1000篇 |
2011年 | 1119篇 |
2010年 | 657篇 |
2009年 | 512篇 |
2008年 | 880篇 |
2007年 | 976篇 |
2006年 | 940篇 |
2005年 | 872篇 |
2004年 | 829篇 |
2003年 | 789篇 |
2002年 | 742篇 |
2001年 | 156篇 |
2000年 | 135篇 |
1999年 | 162篇 |
1998年 | 171篇 |
1997年 | 112篇 |
1996年 | 91篇 |
1995年 | 90篇 |
1994年 | 84篇 |
1993年 | 69篇 |
1992年 | 68篇 |
1991年 | 72篇 |
1990年 | 59篇 |
1989年 | 64篇 |
1988年 | 37篇 |
1987年 | 35篇 |
1986年 | 24篇 |
1985年 | 27篇 |
1984年 | 26篇 |
1983年 | 16篇 |
1982年 | 28篇 |
1981年 | 18篇 |
1980年 | 25篇 |
1979年 | 22篇 |
1978年 | 14篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1974年 | 9篇 |
1973年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
This instrument has been constructed with the purpose of quantifying the severity of depressive states, i.e. to identify the depressive patient and to measure the response to treatment with an antidepressant. Type of instrument: Ordinal rating scale, 11 items, 5 grades. Eleven variables are assessed: Activity (motor); Activity (verbal); Retardation (intellectual); Anxiety (psychic); Suicidal impulses; Lowered mood; Self-depreciation and guilt feelings; Emotional retardation; Sleep disturbances; Tiredness and pain; Work and interests. Tests were done to verify concurrent validity with the Hamilton Depression Scale (HDS); some data on inter-observer reliability are given. 相似文献
32.
We examined the correlates of self-reported lifetime use of alcohol, marijuana, amphetamines, and cocaine within a sample of almost 7,000 high school sophomores in Arizona and Utah. Correlates of drug use (including parental attachment, religious attachment, educational attachment, conventional values, and drug-using friends) showed very similar patterns by gender, with some interesting differences by location. Drug-using friends are by far the best predictor of drug use for both males and females in Arizona and Utah. 相似文献
33.
34.
Toshiyuki Matsui Sumio Tsuda Hiroaki Matake Keisuke Ikeda Tsuneyoshi Yao 《Digestive endoscopy》2004,16(Z1):S27-S30
Background: Gastrointestinal strictures are the most often and serious complication in Crohn's disease. Because of the frequent postoperative recurrence in Crohn's disease, endoscopic therapy of gastrointestinal stricture is one of the best therapeutic options. Method: The present study sets out the results from a prospective study of endoscopic dilation therapy on 48 Crohn's disease patients with severe gastrointestinal stenoses. All patients who could not undergo endoscopic balloon dilation therapy (EBD) were operated on. Results: Long‐term success was attained in 32 of the 48 patients; cumulative avoidance of surgery after EBD was 86% at one year and 71% at three. Second, the most hazardous factor was recurrent inflammation causing restenosis. Patients who had strictures with oral luminal dilatation and patients with frequent recurrence had a tendency to be operated on. As a complication, perforation occurred in two cases (3.3%). Conclusions: EBD therapy for Crohn's stricture in the gastrointestinal tract is recommended before surgical intervention. 相似文献
35.
36.
In vivo MRI of cancer cell fate at the single-cell level in a mouse model of breast cancer metastasis to the brain. 总被引:7,自引:0,他引:7
Chris Heyn John A Ronald Soha S Ramadan Jonatan A Snir Andrea M Barry Lisa T MacKenzie David J Mikulis Diane Palmieri Julie L Bronder Patricia S Steeg Toshiyuki Yoneda Ian C MacDonald Ann F Chambers Brian K Rutt Paula J Foster 《Magnetic resonance in medicine》2006,56(5):1001-1010
Metastasis (the spread of cancer from a primary tumor to secondary organs) is responsible for most cancer deaths. The ability to follow the fate of a population of tumor cells over time in an experimental animal would provide a powerful new way to monitor the metastatic process. Here we describe a magnetic resonance imaging (MRI) technique that permits the tracking of breast cancer cells in a mouse model of brain metastasis at the single-cell level. Cancer cells that were injected into the left ventricle of the mouse heart and then delivered to the brain were detectable on MR images. This allowed the visualization of the initial delivery and distribution of cells, as well as the growth of tumors from a subset of these cells within the whole intact brain volume. The ability to follow the metastatic process from the single-cell stage through metastatic growth, and to quantify and monitor the presence of solitary undivided cells will facilitate progress in understanding the mechanisms of brain metastasis and tumor dormancy, and the development of therapeutics to treat this disease. 相似文献
37.
Kawashima Yoshiaki Cui Fude Takeuchi Hirofumi Niwa Toshiyuki Hino Tomoaki Kiuchi Katsumi 《Pharmaceutical research》1995,12(7):1040-1044
Purpose. Poorly compressible crystals of acebutolol hydrochloride were agglomerated by the spherical crystallization technique with a two-solvent system to improve the compressibility for direct tabletting. The mechanism of improvements in static compression behaviors and tablettabilities of the spherically agglomerated crystals were investigated.
Methods. The improvement of static compression behaviors of the agglomerated crystals was determined by measuring the stress relaxations and elastic recoveries of compressed powder of original and agglomerated crystals. The improved tablettability of agglomerated crystals was evaluated by the pressure transmission ratio upon compression, the ejection pressure for releasing the tablet from the die and the tablet strength, i.e., tensile strength required for breaking.
Results. The higher relaxation pressure and the lower elastic recovery of the agglomerated crystals than of the original crystals were found. The pressure transmission ratio data showed that the friction pressures of the two crystals were similar during the compression period. The ejection pressure of the agglomerated crystals was lower than that of the original crystals. The tensile strength of the tablet of agglomerated crystals was greater than that of the original crystals.
Conclusions. The compressibility and tablettability of the spherically agglomerated crystals prepared by the spherical crystallization technique were much improved due to their increased plastic property and reduced adhesive property compared to the original crystals. 相似文献
38.
BACKGROUND/AIMS: Hepatocytes (HEP) have been the major target for structural quantification in the liver, but an estimation of their total number (N), their percentage in relation to the global number of liver cells and the evaluation of the percentage of binucleated hepatocytes (BnHEPs) have never been performed with modern design-based stereological techniques. The establishment of sound technical guidelines and baseline quantitative data in non-pathological conditions are relevant to properly evaluate HEP hyperplasia and BnHEP responses. METHODS: In this study, we combined immunocytochemistry with sound design-based stereology for estimating the N of HEP and the N of non-hepatocytic cells (NHCs). For obtaining systematic uniform random sections (30 microm thick), a smooth fractionator sampling scheme was applied to the liver of five male Wistar rats (3 month old). Those sections were immunostained with polyclonal antibodies against carcinoembryonic antigen. Because biliary canaliculi were then marked, an unequivocal counting of mononucleated hepatocytes (MnHEP) and BnHEP was allowed. RESULTS: The N of HEP was estimated to be 1.93 x 10(9), with a coefficient of error (CE) of 0.02, corresponding to 129 x 10(6) HEP/g of liver. BnHEP represented 26% of total HEP number. The N of NHC was estimated as 1.31 x 10(9) (CE=0.02). CONCLUSION: The strategy here presented provides a reliable method for accessing the N of HEP (distinguishing MnHEP from BnHEP) in situations in which these parameters are relevant, namely for evaluating the magnitude of an hyperplastic liver response from its very early onset. 相似文献
39.
Taking occlusal photographs can be challenging; they are by far the most difficult images to obtain. Achieving an ideal photograph of every arch may not always be possible. In patients with limited range of motion of the mandible, an oversized or hyperactive tongue, an excessive gag reflex, or reduced flexibility of lips and checks, the goal of an ideal occlusal photograph may not be achieved. Nevertheless, patience, practice, and attention to detail can often provide a satisfactory result. 相似文献
40.
Hiroshi Yano Masahiro Murakami Yoshiaki Nakano Takeshi Tono Tadashi Ohnishi Takashi Iwazawa Yutaka Kimura Toshiyuki Kanoh Takushi Monden 《Digestive endoscopy》2004,16(4):343-346
We performed laparoscopic appendectomy and drainage to treat panperitonitis due to perforated appendicitis that occurred in a 28‐year‐old woman. We believe this is an appropriate procedure to treat perforated appendicitis because it is safe and minimally invasive, and faster recovery can be expected than after conventional open appendectomy. 相似文献