全文获取类型
收费全文 | 9365篇 |
免费 | 1187篇 |
国内免费 | 70篇 |
专业分类
耳鼻咽喉 | 119篇 |
儿科学 | 343篇 |
妇产科学 | 183篇 |
基础医学 | 1241篇 |
口腔科学 | 250篇 |
临床医学 | 1021篇 |
内科学 | 2494篇 |
皮肤病学 | 225篇 |
神经病学 | 589篇 |
特种医学 | 521篇 |
外科学 | 886篇 |
综合类 | 344篇 |
一般理论 | 4篇 |
预防医学 | 960篇 |
眼科学 | 116篇 |
药学 | 846篇 |
中国医学 | 12篇 |
肿瘤学 | 468篇 |
出版年
2021年 | 114篇 |
2020年 | 89篇 |
2019年 | 137篇 |
2018年 | 144篇 |
2017年 | 129篇 |
2016年 | 154篇 |
2015年 | 178篇 |
2014年 | 222篇 |
2013年 | 284篇 |
2012年 | 370篇 |
2011年 | 439篇 |
2010年 | 237篇 |
2009年 | 233篇 |
2008年 | 325篇 |
2007年 | 392篇 |
2006年 | 401篇 |
2005年 | 414篇 |
2004年 | 356篇 |
2003年 | 324篇 |
2002年 | 319篇 |
2001年 | 326篇 |
2000年 | 303篇 |
1999年 | 259篇 |
1998年 | 172篇 |
1997年 | 146篇 |
1996年 | 143篇 |
1995年 | 164篇 |
1994年 | 121篇 |
1993年 | 134篇 |
1992年 | 210篇 |
1991年 | 216篇 |
1990年 | 192篇 |
1989年 | 220篇 |
1988年 | 209篇 |
1987年 | 202篇 |
1986年 | 204篇 |
1985年 | 192篇 |
1984年 | 153篇 |
1983年 | 108篇 |
1982年 | 107篇 |
1981年 | 100篇 |
1980年 | 93篇 |
1979年 | 133篇 |
1978年 | 85篇 |
1977年 | 89篇 |
1976年 | 81篇 |
1975年 | 79篇 |
1974年 | 83篇 |
1973年 | 90篇 |
1971年 | 66篇 |
排序方式: 共有10000条查询结果,搜索用时 30 毫秒
71.
72.
Fundus-first laparoscopic cholecystectomy 总被引:1,自引:1,他引:0
I. G. Martin S. P. L. Dexter J. Marton J. Gibson J. Asker A. Firullo M. J. McMahon 《Surgical endoscopy》1995,9(2):203-206
Removal of the gallbladder with commencement of dissection at the fundus is well recognized as a safe technique during difficult open cholecystectomy because it minimizes the risks of damage to the structures in or around Calot's triangle. We report here the routine employment of liver retractors and fundus-first dissection during laparoscopic cholecystectomy (LC) as an alternative to techniques previously described.Retraction of the liver and fundus-first dissection was used in 53 patients who underwent laparoscopic cholecytectomy. There were 16 male and 37 female patients. Seven were operations performed during an acute admission and 20 had moderate or severe adhesions involving the gallbladder. Thirteen patients had a preexisting abdominal incision.The procedure was successful in 52 patients (98%), but in one patient it was converted to open operation because of dense adhesions. Median duration of operation was 90 min (range 35–240 min). There was no mortality and two complications (persistent right upper quadrant pain for 2 weeks after operation and bile leakage from the gallbladder bed).The facility to retract the liver and carry out a fundus-first dissection extends techniques developed for open surgery into the laparoscopic arena. It offers the surgeon the safety and versatility during laparoscopic cholecystectomy that it confers during conventional open surgery.Presented at the annual meeting of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES), Nashville, Tennessee, USA, 18–19 April 1994 相似文献
73.
74.
75.
OBJECTIVE: The present study sought to examine use prevalence and factors associated with use of analgesic and psychotropic medications in community-dwelling older people with chronic non-malignant pain. METHOD: The study group comprised 193 community-dwelling older people with daily chronic non-malignant pain who were selected from a random sample of 1,000 older people in Melbourne. RESULTS: The use prevalence for the study group was 63% for analgesics and 39% for psychotropic medications, which is higher than the general older population without chronic pain (p < 0.00001). More women with chronic pain used analgesics, while psycho-social factors such as problems with sleeping and living at home alone were found to be associated with an increased use of psychotropic medications. CONCLUSION: A high proportion of community-dwelling older people with chronic non-malignant pain use analgesic and psychotropic medications. IMPLICATIONS: These findings provide the basis for further investigation into the level and appropriateness of analgesic and psychotropic medication use by older people with chronic pain. 相似文献
76.
77.
K A Leonard M I Nelen L T Anderson S L Gibson R Hilf M R Detty 《Journal of medicinal chemistry》1999,42(19):3942-3952
Cationic chalcogenopyrylium dyes 2-4 were synthesized in six steps from 4-(dimethylamino)phenylethyne (7), have absorption maxima in methanol of 594, 631, and 672 nm, respectively, and generate singlet oxygen with quantum yields [Phi((1)O(2))] of 0.020, 0.064, and 0.037, respectively. Dyes 2-4 are hydrolytically more stable than other chalcogenopyrylium dyes evaluated previously as sensitizers for photodynamic therapy. At 10 microM final concentration, all dyes 2-4 inhibited cytochrome c oxidase during irradiation of tumor mitochondrial suspensions treated with 10 microM dye. The degree of enzyme inhibition was abated in a reduced oxygen environment and in the presence of imidazole, a singlet oxygen trap. Superoxide dismutase, at a final concentration of 30 U, did not alter the photosensitized inhibition of mitochondrial cytochrome c oxidase by dyes 2-4. These data suggest that singlet oxygen may play a major role in the photosensitized inhibition of mitochondrial cytochrome c oxidase. Irradiation of R3230AC rat mammary adenocarcinoma cells in the presence of dyes 2-4 caused a significant loss in cell viability with thiopyrylium dye 2 displaying the greatest phototoxicity. Initial acute toxicity studies in vivo demonstrate that, at 10 mg/kg, none of the three dyes displayed overt toxicity. 相似文献
78.
79.
V W Jiang R E Gibson W J Rzeszotarski W C Eckelman R C Reba 《Journal of nuclear medicine》1978,19(8):918-924
Four new beta-adrenoceptor blocking agents carrying tyramine as the amino moiety were synthesized and the distribution of their I-125-tagged derivatives evaluated in rats. This distribution was compared with the distribution of various agonists and antagonists labeled with H-3 and C-14, and with the in vitro binding affinity of the new derivatives. A radioiodinated derivative of a cardioselective blocker, alprenolol, showed poor blood clearance and no cardiac selectivity. A derivative of another cardioselective blocker, practolol, showed a promising heart-to-blood ratio (ca. 19) and cardioselectivity with a heart-to-lung ratio of ca. 2. Two additional practolol analogs showed no improvement over the practolol derivative; because of the increased lipophilicity of these derivatives, blood clearance and cardioselectivity were diminished. An inverse correlation is suggested between the dissociation constant for the beta adrenoceptor in the lung and the heart-to-blood and heart-to-lung values. We conclude that polarity plays an important role in the blood clearance and cardioselectivity of these beta-adrenoceptor derivatives. 相似文献
80.