全文获取类型
收费全文 | 17274篇 |
免费 | 1083篇 |
国内免费 | 162篇 |
专业分类
耳鼻咽喉 | 207篇 |
儿科学 | 362篇 |
妇产科学 | 171篇 |
基础医学 | 2179篇 |
口腔科学 | 258篇 |
临床医学 | 1329篇 |
内科学 | 4838篇 |
皮肤病学 | 327篇 |
神经病学 | 1139篇 |
特种医学 | 707篇 |
外科学 | 2421篇 |
综合类 | 215篇 |
一般理论 | 21篇 |
预防医学 | 1177篇 |
眼科学 | 377篇 |
药学 | 1046篇 |
中国医学 | 61篇 |
肿瘤学 | 1684篇 |
出版年
2023年 | 98篇 |
2022年 | 220篇 |
2021年 | 367篇 |
2020年 | 251篇 |
2019年 | 364篇 |
2018年 | 403篇 |
2017年 | 370篇 |
2016年 | 432篇 |
2015年 | 480篇 |
2014年 | 599篇 |
2013年 | 725篇 |
2012年 | 1216篇 |
2011年 | 1153篇 |
2010年 | 714篇 |
2009年 | 563篇 |
2008年 | 1094篇 |
2007年 | 1212篇 |
2006年 | 1091篇 |
2005年 | 1126篇 |
2004年 | 984篇 |
2003年 | 1065篇 |
2002年 | 995篇 |
2001年 | 232篇 |
2000年 | 204篇 |
1999年 | 222篇 |
1998年 | 205篇 |
1997年 | 201篇 |
1996年 | 164篇 |
1995年 | 151篇 |
1994年 | 114篇 |
1993年 | 97篇 |
1992年 | 132篇 |
1991年 | 110篇 |
1990年 | 99篇 |
1989年 | 107篇 |
1988年 | 82篇 |
1987年 | 72篇 |
1986年 | 74篇 |
1985年 | 74篇 |
1984年 | 53篇 |
1983年 | 59篇 |
1982年 | 41篇 |
1981年 | 41篇 |
1980年 | 37篇 |
1979年 | 38篇 |
1978年 | 34篇 |
1977年 | 54篇 |
1976年 | 30篇 |
1974年 | 29篇 |
1973年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
Heather A McKay Harri Siev?nen Moira A Petit Kerry J MacKelvie Ken M Forkheim Ken P Whittall Bruce B Forster Heather Macdonald 《Journal of clinical densitometry》2004,7(2):161-168
Conventional density measures by dual-energy X-ray absorptiometry (DXA) are confounded by increases in bone size and do not assess bone geometry. We assessed precision of magnetic resonance imaging (MRI) and used MRI, DXA, and hip structure analysis (HSA) to assess 7-mo changes in bone structure at the femoral neck in 18 prepubertal girls. At baseline, girls were 10.4 (0.5) yr, 144.0 (8.2) cm, and 35.2 (7.0) kg, on average. Total bone and cortical cross-sectional area (ToA and CoA) were calculated from high-resolution T1-weighted MRI oblique axial images of the femoral neck. We used proximal femur DXA scans (Hologic QDR-4500) and the HSA program to estimate bone cross-sectional area (CSA), and calculate section modulus. MRI precision was determined by scanning 10 volunteers (13-46 yr old) three times with and without repositioning. Precision (CVrms) was 2% for ToA and 7% for CoA. Significant correlations were observed between FN area and MRI-derived ToA (r = 0.57, p = 0.013) and CoA (r = 0.47, p = 0.050). There were significant positive changes over 7 mo by both methods. In conclusion, MRI provides useful information on femoral neck bone area in children. The reproducibility of cortical dimensions at the femoral neck needs improvement through technical modifications and appropriate analysis software. 相似文献
63.
Papillo-Choledochectomy in the Operative Management of Mucosal Neoplasms of the Periampullary Region
Kogoro Kasahara Ken Saito Yasuo Kondo Toshihiko Yasuda Yoshikazu Yasuda Masatoshi Nakada Hideo Nagai Kyotaro Kanazawa 《HPB surgery》1993,6(3):211-217
Two patients with mucosal cancer of the periampullary region were treated with papillocholedochectomy,
which entails removal of the papilla of Vater and the whole length of the common bile duct. The neoplasm is dissected out through the plane between the duodenal circular and longitudinal muscles, deep to the sphincter of Oddi and the fibromuscular layer of the bile duct. Pathological examination showed that cancer was confined to the mucosal layer without stromal invasion, and that the operation achieved radical cure. For mucosal cancer, papillo-choledochectomy is
an alternative to pancreatoduodenectomy, provided that repeated frozen-section studies confirm the
completeness of excision. 相似文献
64.
65.
Koichi Akamatsu Soichiro Miyauchi Kenji Ohshima Shunji Okita Yoshifumi Yasuhara Hiroshi Mogami Yasuyuki Ohta Ken Hamamoto 《Cancer chemotherapy and pharmacology》1989,23(Z1):S59-S64
Transcatheter arterial embolization (TAE) with the concurrent use of caerulein was assessed for the purpose of preventing gallbladder complications often seen after TAE of hepatic carcinoma. Ninety-six cases with primary hepatic carcinoma, who had undergone TAE in the right hepatic arterial region over the past 4 years, were divided into three groups: 22 cases for which embolization was possible on a selective basis by passing the catheter to the peripheral side beyond the bifurcated region of the cystic artery; 40 cases who had undergone TAE in which caerulein was not administered, from the central side of the bifurcated region of the cystic artery; and 34 cases given 20 g caerulein 15–30 min before TAE. A comparison was made using the abdominal pain, pyrexia, rate of leukocytosis and the US findings of the gallbladder as the indices of the gallbladder complications. As a result, it become evident that it was possible to prevent or alleviate gallbladder complications if caerulein were administered before TAE in cases where the embolizing substances were infused in the right hepatic artery from the central side of the bifurcated region of the cystic artery. It was conclusively shown that the gallbladder blood flow decreases if the organ is contracted by caerulein, which in turn causes a decrease in the inflow of the embolizing substances whereby complications are alleviated. 相似文献
66.
Kitajima T Kanbayashi T Saito Y Takahashi Y Ogawa Y Sugiyama T Kaneko Y Aizawa R Shimizu T 《Neuroscience letters》2004,355(1-2):77-80
It is known that benzodiazepines have a hypotensive effect, but the mechanism has not been well elucidated yet. To clarify whether this effect is due to central or peripheral mechanism, we administered 5 mg of diazepam or saline intravenously to healthy volunteers and assessed the change in blood pressure, heart rate, muscle sympathetic nerve activity and heart rate variability. After diazepam administration, systolic and mean blood pressure decreased significantly. Muscle sympathetic nerve activity was also significantly reduced but heart rate did not change, whereas the variables of spectral analysis of heart rate variability did not show significant change. We concluded that the hypotensive effect of diazepam in human is mainly due to the central mechanism. 相似文献
67.
Wakabayashi Y Watanabe H Inoue J Takeda N Sakata J Mishima Y Hitomi J Yamamoto T Utsuyama M Niwa O Aizawa S Kominami R 《Nature immunology》2003,4(6):533-539
The gene Bcl11b, which encodes zinc finger proteins, and its paralog, Bcl11a, are associated with immune-system malignancies. We have generated Bcl11b-deficient mice that show a block at the CD4-CD8- double-negative stage of thymocyte development without any impairment in cells of B- or gammadelta T cell lineages. The Bcl11b-/- thymocytes showed unsuccessful recombination of V(beta) to D(beta) and lacked the pre-T cell receptor (TCR) complex on the cell surface, owing to the absence of Tcrb mRNA expression. In addition, we saw profound apoptosis in the thymus of neonatal Bcl11b-/- mice. These results suggest that Bcl11b is a key regulator of both differentiation and survival during thymocyte development. 相似文献
68.
Tadao Fukushima Yoji Nagashima Yukio Nakatani Nobuko Nakarnura Kiyoshi Fukasawa Yoshiaki Satomi Ken Yu Yohei Miyagi Ichiro Aoki Kazuaki Misugi 《Pathology international》1994,44(5):401-406
Chromophobe renal cell carcinoma (RCC) is a recently established subtype of RCC, which has rarely been reported in Japan. In this communication, the authors report two Japanese cases of chromophobe RCC together with the immunohistochemical findings. The tumors were composed of sheets and cribriform glands formed by tumor cells with cloudy and reticular cytoplasm. Ultrastructurally, the cytoplasm was filled with numerous microvesicles. The tumor cells were positive for cytokeratin, epithelial membrane antigen, and Tamm-Horsfall protein. Occasionally, LeuM1-positive cells were also noted. Vimentin was negative, unlike the usual RCC. Reactivity for peanut agglutinin was more frequent than that to Lotus tetragonolobus agglutinin. The results of this study suggest that the tumor cellq possessed phenotypes similar to the distal nephron rather than to the proximal tubular cells. 相似文献
69.
W. Ken Busfield Ian M. G. Cowie M. A. Sattar Mondal 《Macromolecular chemistry and physics.》1979,180(7):1775-1786
Two series of block copolymers have been synthesized comprising of soft polytrifluoroacetaldehyde (polyacetal) segments and of hard 4,4′-methylenedi(phenyl isocyanate)/cis-cyclohexane-1,4-diol polyurethane segments. The series-A copolymers in which the soft segments were directly bound to the hard segments had significantly lower thermal stability than the series-B copolymers in which the soft segments were linked to the hard segments by sebacic ester units. In both series the thermal stability decreased with increasing soft segment content. The series-A copolymers exhibited two thermal transitions both characteristic of Tg's and separated by about 60 K. In contrast the series-B copolymers exhibited two characteristic Tg's separated by 200–250 K, depending on composition, together with an additional endothermic transition at about ambient temperature. All transitions for both series decreased with increasing soft segment content. The observations have been compared with those of other polyether and polyester based polyurethanes. 相似文献
70.
Ken SAITO Hideo SHIMIZU Takeshi YOKOYAMA Katsuya KAWATA Takanori MATSUMURA Yasuhiko MORIOKA 《Pathology international》1983,33(2):249-256
Four cases of Ischemic enterocolitis without arterio–occlusive lesion were described. Three cases were associated with sigmoid colon carcinomas. Ischemic lesions developed anal to the carcinomas in two cases, and oral to sigmoidostomy to relieve intestinal obstruction by carcinoma in one case. One other case was associated with inguinal hernia. Grossly, ischemic lesions involved relatively short intestinal segments, and the ischemic colonic lesions were not related to teniae coli. Extensive veno–occlusive lesions were discovered in a case of ischemic stricture of the ileum, which had been incarcerated in the right inguinal hernia. Reversible mechanical occlusion of the intestinal vessels caused by transient or recurrent intestinal strangulation is the most probable cause of these ischemic lesions., ACTA PATHOL. JPN. 33: 249–256, 1983. 相似文献