全文获取类型
收费全文 | 181851篇 |
免费 | 1296篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 1259篇 |
儿科学 | 6737篇 |
妇产科学 | 3060篇 |
基础医学 | 17408篇 |
口腔科学 | 1709篇 |
临床医学 | 12737篇 |
内科学 | 32475篇 |
皮肤病学 | 719篇 |
神经病学 | 16923篇 |
特种医学 | 9178篇 |
外科学 | 29747篇 |
综合类 | 2335篇 |
预防医学 | 18211篇 |
眼科学 | 3003篇 |
药学 | 10109篇 |
中国医学 | 632篇 |
肿瘤学 | 16938篇 |
出版年
2022年 | 80篇 |
2021年 | 131篇 |
2020年 | 76篇 |
2019年 | 106篇 |
2018年 | 22011篇 |
2017年 | 17413篇 |
2016年 | 19603篇 |
2015年 | 1006篇 |
2014年 | 927篇 |
2013年 | 914篇 |
2012年 | 7165篇 |
2011年 | 21215篇 |
2010年 | 18953篇 |
2009年 | 11611篇 |
2008年 | 19708篇 |
2007年 | 21903篇 |
2006年 | 781篇 |
2005年 | 2439篇 |
2004年 | 3652篇 |
2003年 | 4623篇 |
2002年 | 2771篇 |
2001年 | 569篇 |
2000年 | 705篇 |
1999年 | 416篇 |
1998年 | 296篇 |
1997年 | 274篇 |
1996年 | 161篇 |
1995年 | 159篇 |
1994年 | 150篇 |
1993年 | 114篇 |
1992年 | 244篇 |
1991年 | 256篇 |
1990年 | 295篇 |
1989年 | 241篇 |
1988年 | 217篇 |
1987年 | 194篇 |
1986年 | 153篇 |
1985年 | 139篇 |
1984年 | 114篇 |
1983年 | 95篇 |
1982年 | 68篇 |
1980年 | 73篇 |
1979年 | 77篇 |
1978年 | 65篇 |
1974年 | 54篇 |
1970年 | 62篇 |
1969年 | 54篇 |
1968年 | 62篇 |
1938年 | 60篇 |
1932年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Irwin L. Flink 《Brain structure & function》2002,205(3):235-244
32.
33.
34.
35.
Mitsumasa Iwata Shunji Izuta Motoshi Suzuki Kiyohide Kojima Yoshihito Furuhashi Yutaka Tomoda Shonen Yoshida 《Cancer science》1991,82(4):433-439
We examined the mechanisms of the inhibition of DNA synthesis by a new platinum compound, (-)-( R )-2-aminomethylpyrrolidine(1,1-cyclobutane-dicarboxylato)-2-platinum(II) monohydrate (DWA-2114R), a derivative of the antitumor drug cis- diamminedichloroplatinum(II) (CDDP), using prokaryotic and eukaryotic DNA polymerases. Preincubating activated DNA with CDDP or DWA-2114R reduced its template activity for prokaryotic and eukaryotic DNA polymerases in a dose-dependent manner. DWA2114R required six times greater drug concentration and two times longer incubation time to show the same decrease of the template activity compared to CDDP. Treatment of primed pUC118 ssDNA templates with the two drugs followed by second-strand synthesis by prokaryotic and eukaryotic DNA polymerases revealed that DWA2114R bound to DNA in a similar manner to CDDP and these adducts blocked DNA elongation by DNA polymerases of eukaryotes as well as of prokaryotes. With these two drugs, the elongations by E. coli DNA polymerase I (Klenow fragment), T7 DNA polymerase and calf thymus DNA polymerase α were strongly arrested at guanine-guanine sequences (GG). Stop bands were also observed at adenine-guanine sequences (AG) guanine-adenine-guanine sequences (GAG) and mono-guanine sequence (G). Calf testis DNA polymerase β was also arrested efficiently at AG, GAG and G, but much more weakly at GG. This pattern was common to DWA2114R and CDDP. 相似文献
36.
Effects of N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl)acetamide (DM-9384) on learning and memory in rats 总被引:1,自引:0,他引:1
Effects of N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide (DM-9384) on learning and memory were studied using four different experimental rat models. In electroconvulsive shock- or scopolamine-induced amnesia in the step-through passive avoidance task, DM-9384 improved both types of amnesia when administered before the training trial. Aniracetam also showed similar but somewhat weaker effects. Furthermore, in the scopolamine amnesia model, an improvement was confirmed with arecoline. The dose-response curves for these compounds were bell-shaped. In the shuttle box active avoidance task, DM-9384 administered daily 1 hr before each training session facilitated the acquisition process of the avoidance response. In addition, the experiment of light-dark discrimination task with positive reinforcement showed that this compound administered daily after each session slightly accelerated the acquisition process of the correct response. These results suggest an ability of DM-9384 to enhance cognitive functions. 相似文献
37.
38.
Joe Matsumoto Tetsufumi Kojima Tetsuya Shimizu Shuji Kitashiro Kazuya Konishi Yoshiyuki Matsumura You Kawarada Hitoshi Ikeda Takashi Yoshiki 《Annals of thoracic and cardiovascular surgery》2002,8(3):151-153
In lung cancer patients, hypercalcemia is a fairly common metabolic problem associated with malignancy. However, the occurrence of hypercalcemia in lung cancer patients means an ominous prognostic sign. As hypercalcemia often causes early death, quick diagnosis and treatment for hypercalcemia are required. A 69-year-old woman was admitted to our hospital with anorexia caused by hypercalcemia. On admission, serum level of PTH was elevated and PTHrP was normal. From the results of CT findings and transbronchial lung biopsy, the cause of the hypercalcemia was determined as lung cancer incidentally complicated with primary hyperparathyroidism. First, serum calcium level was returned to normal through hydration with saline and bisphosphonates. Next, left hemithyroidectomy for primary hyperparathyroidism was performed. Histologically, the tumor was diagnosed as parathyroid adenoma. Fifteen days later, left lower lobectomy for primary lung cancer was performed under a video-assisted thoracoscopic approach. Histologically, the tumor was diagnosed as a moderately differentiated adenocarcinoma. Four years and three months after the operation, the patient is alive and well with no sign of recurrence. When a lung cancer patient is complicated with hypercalcemia, we need to consider that primary hyperparathyroidism is a possible cause of the hypercalcemia. 相似文献
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