全文获取类型
收费全文 | 186301篇 |
免费 | 1749篇 |
国内免费 | 87篇 |
专业分类
耳鼻咽喉 | 1230篇 |
儿科学 | 6872篇 |
妇产科学 | 3094篇 |
基础医学 | 17763篇 |
口腔科学 | 1817篇 |
临床医学 | 13073篇 |
内科学 | 33997篇 |
皮肤病学 | 1080篇 |
神经病学 | 17115篇 |
特种医学 | 9458篇 |
外科学 | 30617篇 |
综合类 | 2352篇 |
一般理论 | 1篇 |
预防医学 | 18340篇 |
眼科学 | 2866篇 |
药学 | 10146篇 |
中国医学 | 643篇 |
肿瘤学 | 17673篇 |
出版年
2023年 | 139篇 |
2022年 | 281篇 |
2021年 | 511篇 |
2020年 | 263篇 |
2019年 | 351篇 |
2018年 | 22254篇 |
2017年 | 17651篇 |
2016年 | 19814篇 |
2015年 | 1282篇 |
2014年 | 1301篇 |
2013年 | 1268篇 |
2012年 | 7797篇 |
2011年 | 21794篇 |
2010年 | 19214篇 |
2009年 | 11870篇 |
2008年 | 20067篇 |
2007年 | 22280篇 |
2006年 | 1131篇 |
2005年 | 2700篇 |
2004年 | 3833篇 |
2003年 | 4703篇 |
2002年 | 2858篇 |
2001年 | 479篇 |
2000年 | 609篇 |
1999年 | 348篇 |
1998年 | 279篇 |
1997年 | 279篇 |
1996年 | 147篇 |
1995年 | 139篇 |
1994年 | 135篇 |
1993年 | 98篇 |
1992年 | 175篇 |
1991年 | 209篇 |
1990年 | 222篇 |
1989年 | 189篇 |
1988年 | 132篇 |
1987年 | 106篇 |
1986年 | 98篇 |
1985年 | 102篇 |
1984年 | 80篇 |
1983年 | 69篇 |
1982年 | 45篇 |
1980年 | 56篇 |
1979年 | 51篇 |
1974年 | 43篇 |
1970年 | 38篇 |
1969年 | 41篇 |
1938年 | 60篇 |
1932年 | 56篇 |
1930年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Yuichiro Nakai MD DMSc Takeshi Maeda MD Junko Nishio MD DMSc Daisuke Tachibana MD Motoharu Imanaka MD DMSc Sachio Ogita MD DMSc 《The Australian & New Zealand journal of obstetrics & gynaecology》1998,38(4):469-471
EDITORIAL COMMENT: We accepted this case for publication to remind readers that although uterine rupture during labour in a primigravida is extremely uncommon it does occur, or at any rate nulliparas can develop abdominal pain and shock in labour with a haemoperitoneum resulting from a tear in a vein in the lower posterior uterine wall. When one sees the hugely dilated uterine and ovarian venous plexuses at Caesarean section it is easy to believe that bleeding from such a vessel during labour could be prodigious. This case suggests that a dilated vein with blood flow derangements may be the cause. Nonetheless, as the authors warn us, the necessary response is not a precise diagnosis, but rapid laparotomy. See also Editorial Comment to Chin MMS, Harvey JA, Duffy BL. Uterine rupture during labour in a primigravida. Aust NZ J Obstet Gynaecol 1996; 36: 210. 相似文献
32.
A new method for protecting intestinal anastomoses in patients at high risk of anastomotic dehiscence or fistula formation is described herein. This method involves raising a seromuscular flap on a pedicle from the stump of the intestine to be anastomosed. The anastomosis is performed, then covered with the seromuscular flap. 相似文献
33.
CYP2E1 and ALDH2 Genotypes and Alcohol Dependence in Japanese 总被引:2,自引:0,他引:2
Kazuhiko Iwahashi Yoshinori Matsuo Hiroshi Suwaki Kazuhiko Nakamura Yoshiyuki Ichikawa 《Alcoholism, clinical and experimental research》1995,19(3):564-566
The genotypes of the CYP2E1 and ALDH2 loci of alcoholic (alcohol dependence) and nonalcoholic (healthy) Japanese were investigated to examine the relationship between the polymorphism of CYP2E1 (C1 /C2 ) and ALDH2 ( ALDH2*1/ALDH2*2 ), and the susceptibility to alcoholism. There was no significant difference in C2 gene frequency between alcoholics (0.19) and nonalcoholics (controls) (0.20), whereas there was a significant difference in ALDH2 allele frequency, suggesting that, in Japanese, the C2 genotype of CYP2E1 may have nothing to do with the risk of developing alcohol dependence. However, the ALDH2*1 allele may influence drinking behavior and the development of alcohol dependence. Furthermore, racial interethnic differences in the frequency of the mutated allele of the CYP2E1 gene (CJ were found, like the ALDH2 gene. Japanese healthy controls showed a significantly higher frequency of the C2 allele than did Swedish healthy controls (0.05; reported by Persson et al., FEBS Lett. 319:207-211,1993). 相似文献
34.
Irwin L. Flink 《Brain structure & function》2002,205(3):235-244
35.
H S Ozaki K Iwahashi M Tsubaki Y Fukui Y Ichikawa Y Takeuchi 《Journal of neuroscience research》1991,28(4):518-524
The presence of cytochrome P-45011 beta in rat brain was studied by immunohistochemistry using polyclonal rabbit antibodies raised against purified bovine adrenocortical P-45011 beta, which is involved in the steroid 11 beta-hydroxylation and glucocorticoid formation. The results showed that cytochrome P-45011 beta immunoreactivity is selectively localized to the tracts of myelinated fibers throughout the brain. The specificity of immunohistochemical stainings with P-45011 beta antibodies was established by control tests including nonimmune rabbit immunoglobulin Gs and P-45011 beta antibodies absorbed with purified antigen. Western immunoblots of homogenates from different brain areas with P-45011 beta antibodies, together with biochemical enzymatic assays for cytochrome P-45011 beta monooxygenase activity in these homogenates, confirmed the selective localization of this enzyme observed with immunohistochemistry. Cytochrome P-45011 beta and 11 beta-hydroxylase activity were detected in a homogenate from the cortical white matter (brain area rich in myelinated fibers) as in that from the rat adrenal, but were not detectable in a homogenate from the cerebral cortex (brain area poor in myelinated fibers). Furthermore, quantitation of the P-45011 beta bands on the immunoblots by the areal density revealed that the cortical white matter contains approximately 1.4 pmol of cytochrome P-45011 beta/mg of tissue protein, the value of which was about one sixth of the corresponding value estimated in the rat adrenal. This relatively high content of cytochrome P-45011 beta was also reflected in a relatively high level of 11 beta-hydroxylase activity measured in a homogenate of this brain area by biochemical enzymatic assays using [4-14C]-11-deoxycorticosterone.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
36.
37.
38.
39.
Paul Hochstein Ulrich Glatzel Thomas Schmickal Andreas Wentzensen 《Trauma und Berufskrankheit》2002,4(2):s110-s114
The treatment of deep cartilage defects in load-bearing joints is a problem that still has no satisfactory solution. Full-thickness defects of the articular cartilage rarely heal spontaneously, usually leaving damage that can lead to early arthrosis. Techniques currently available for the treatment of chondral defects include abrasion, drilling, micro-fracturing, transplantation of tissue autografts and allografts, and cell transplantation. Osteochondral autograft transplantation is currently the only surgical cartilage repair technique known to lead to the formation of genuine hyaline articular cartilage and its retention at least in the medium term. The Draenert method, in which a water-cooled diamond bone-cutting system is used, is an effective procedure for resurfacing the joints affected by localised cartilaginous defects, even when there is also severe bone loss. Donor-side morbidity can be kept to a minimum by filling the defect caused by harvesting with a press-fit cylinder of cancellous bone covered with periosteum for protection. 相似文献
40.
Annemieke Smit-van Oosten Winston W. Bakker Harry van Goor 《Transplant international》2002,15(12):602-609
Ischemic injury plays an important role in chronic renal transplant failure (CRTF). Down-regulation of ecto-adenosine triphosphatase (ATPase) in combination with up-regulation of ecto-5'-nucleotidase is a hallmark of ischemic injury. We studied the expression of renal ecto-5'-nucleotidase and ecto-ATPase in experimental renal transplantation. Fisher 344-to-Lewis allografted rats were either treated with an angiotensin-converting enzyme inhibitor (ACEi) or left untreated. Lewis-to-Lewis syngrafted rats served as controls. Untreated allografted rats developed proteinuria, glomerulosclerosis, and mild intimal hyperplasia. ACEi completely prevented focal and segmental glomerulosclerosis (FGS) and proteinuria, but significantly enhanced intimal hyperplasia. Untreated allografted rats revealed marked vascular ecto-5'-nucleotidase activity, which increased with ACEi. Vascular ecto-5'-nucleotidase activity was absent in syngrafted animals. Ecto-5'-nucleotidase activity correlated well with intimal hyperplasia. Glomerular ecto-ATPase expression was significantly reduced in untreated allografted rats compared to syngrafted rats and correlated well with the extent of FGS. ACEi prevented reduction in glomerular ecto-ATPase. We found de-novo expression of ecto-5'-nucleotidase at sites of renal intimal hyperplasia. Glomerular ecto-ATPase expression was markedly reduced in allografted rats and was prevented by ACEi. These enzyme expression patterns suggest local ischemic damage in experimental CRTF. 相似文献